Comparisons of aortic remodelling and outcomes after endovascular repair of acute and chronic complicated Type B aortic dissections

Comparisons of aortic remodelling and outcomes after endovascular repair of acute and chronic... Abstract OBJECTIVES Patients with acute (ACTBAD) or chronic complicated Type B aortic dissection (CCTBAD) undergoing thoracic endovascular aortic repair (TEVAR) remain at high risk for late aorta-related events. Few data exist on the comparison of aortic remodelling and outcomes after TEVAR between both groups. METHODS Forty-nine patients of TEVAR for CCTBAD (n = 26) and ACTBAD (n = 23) were retrospectively reviewed at our centre. RESULTS The overall 30-day mortality was 4%. Cumulative freedom from all-cause mortality (ACTBAD: 77.6%, CCTBAD: 68.8%; P = 0.76), aneurysmal-related mortality (ACTBAD: 88.2%, CCTBAD: 95.0%; P = 0.63) and the 3-year reintervention rate (ACTBAD: 92.3%, CCTBAD: 95.6%; P = 0.94) were the same in both groups. Aortic remodelling was significant (P < 0.001) above the coeliac level after TEVAR. Thirty-five (75.5%) patients still experienced false lumen flow in the abdominal aorta below the coeliac artery (ACTBAD: 16, CCTBAD: 19, P = 0.10). No difference was found in aortic remodelling between the ACTBAD and CCTBAD groups, and the length of endograft coverage had no impact on the aortic remodelling. CONCLUSIONS The early and 3-year follow-up in our study showed that endovascular repair for both ACTBAD and CCTBAD was safe and effective. Aortic remodelling was favourable above the coeliac artery after TEVAR, and no difference was found between ACTBAD and CCTBAD. The length of endograft coverage had no impact on aortic remodelling. The low rate of false lumen thrombosis in the abdominal aorta warranted continuous imaging surveillance. Aortic remodelling, Aortic dissection, Aortic aneurysm, Endovascular repair, False lumen thrombosis INTRODUCTION The optimal management of Type B aortic dissection (TBAD) remains among the most challenging ongoing investigational issues in thoracic aortic surgery. In uncomplicated cases, a conservative approach with close surveillance seems to be justified if complications develop [1]. In an acute or chronic complicated TBAD, urgent aortic repair is usually required, and thoracic endovascular aneurysm repair (TEVAR) has become the treatment modality of choice since the last decade [2–5]. One of the fundamental concerns between acute complicated TBAD (ACTBAD) and chronic complicated TBAD (CCTBAD) is the fragility of the intimal flap and adventitia that may cause entry tear and subsequent capacity for aortic remodelling after TEVAR [1, 6–10]. Despite the current satisfactory and consistent outcomes, few publications are available that include comparisons of aortic remodelling in the form of false lumen (FL) regression and true lumen (TL) expansion or the reintervention rate for late aortic events between patients having undergone TEVAR for ACTBAD and CCTBAD. The aim of this study was to evaluate 30-day and mid-term outcomes and examine aortic remodelling in thoracic and abdominal aorta in patients having undergone TEVAR for ACTBAD and CCTBAD in our institution. METHODS The research was approved by the institutional review board of the National Taiwan University Hospital Ethics Committee (No. 201403080RIND) as a retrospective cohort study. All the subjects were well informed and gave signed consent. All the clinical procedures and methods were in compliance with the relevant guidelines and regulations. Acute and chronic cases were defined by an elapsed period of less or more than 2 weeks from the onset of symptoms [10–12]. Patients with both acute and chronic complicated TBAD who received TEVAR were included, but patients with connective tissue diseases, atypical aortic dissection such as penetrated aortic ulcer, residual Type A aortic dissection (n = 6) and trauma were excluded. Cerebrospinal fluid drains were inserted depending on a history of previous aortic surgery, the need for left subclavian artery (LSCA) coverage and the anticipated long length of aortic coverage. Endovascular grafts were oversized by 10–15% of the proximally healthy aortic landing zone diameter. Tapered devices or the overlapping tapered technique with additional pieces were selectively used in patients with smaller distal aortic landing zones. To achieve adequate landing and avoid Type 1 endoleak, adjunctive procedures other than stent grafting such as arch vessel debranching were done in some patients as needed [13–17]. Technical success was defined as successful proximal entry tear coverage without conversion to open repair or any Type I endoleak. Follow-up imaging protocols Computerized tomography (CT) was the preferred imaging modality for all patients. CT images were obtained before, at 1 month, 12 months and annually after TEVAR. The maximum diameter of TL and FL in the short axis view (Fig. 1) were accessed at 6 levels: A: the proximal thoracic aorta 2 cm below the LSCA ostium, B: the mid-thoracic aorta at the level of the left inferior pulmonary vein, C: the distal thoracic aorta 2 cm above the diaphragm, D: the coeliac artery, E: the lowest renal arteries, F: the infrarenal aorta at the middle of aortic bifurcation and lowest renal artery using the TeraRecon System (TeraRecon Inc., San Mateo, CA, USA). The procedure details (Table 2) and extent of FL thrombosis (Table 3) were also classified [18, 19]. The changes in TL and FL diameters (TL expansion and FL regression) at the 6 levels between preoperative, 1 month and 12 months were of interest and were checked using a CT scan. The mid-term outcomes included freedom from all-cause and aneurysm-related mortality, and the reintervention rate was analysed. Figure 1: View largeDownload slide Images were obtained at the level of (A) the proximal thoracic aorta 2 cm below the left subclavian artery ostium; (B) the mid-thoracic aorta at the level of the left inferior pulmonary vein; (C) the distal thoracic aorta 2 cm above the diaphragm; (D) the coeliac artery; (E) the lowest renal arteries; (F) the infrarenal aorta at the middle of aortic bifurcation and lowest renal artery. F: FL diameter; T: TL diameter. Figure 1: View largeDownload slide Images were obtained at the level of (A) the proximal thoracic aorta 2 cm below the left subclavian artery ostium; (B) the mid-thoracic aorta at the level of the left inferior pulmonary vein; (C) the distal thoracic aorta 2 cm above the diaphragm; (D) the coeliac artery; (E) the lowest renal arteries; (F) the infrarenal aorta at the middle of aortic bifurcation and lowest renal artery. F: FL diameter; T: TL diameter. Statistical analysis Demographic and periprocedural characteristics were shown as numbers with percentages or as means ± standard deviations. The categorical and continuous variables between the ACTBAD and CTBAD groups were compared by using the Pearson χ2 test and unpaired t-test, respectively. The changes in TL and FL diameters at the 3 time points and the 6 levels of the aorta on CT imaging were presented as means ± standard errors and analysed using the mixed-effects model for longitudinal data. Repeated assessment of each measure was modelled by factors (TL versus FL diameter; ACTBAD versus CCTBAD, aortic coverage above versus below T6 level), time and interaction of factor and time for 6 different positions (a, b, c, d, e and f). A covariance structure was selected first for each model. The justification of covariance structure including 5 different types (unstructured, compound symmetry, variance components, autogressive1, Huynh–Feldt) was compared based on the Akaike information criterion and Schwartz’s Bayesian criterion. Smaller values indicated a better fit. Survival comparisons between the acute and chronic groups were made using the Kaplan–Meier method and the log-rank test. P-values <0.05 were considered statistically significant. All statistical analyses were performed using SAS System Version 9.2 (SAS Institute Inc., Cary, NC, USA). RESULTS Between June 2008 and November 2014, 83 patients with TBAD underwent TEVAR in our institution. The study cohort comprised 49 patients (ACTBAD: 26, CCTBAD: 23) out of 83 patients after exclusion of the patients with connective tissue diseases (n = 4), atypical aortic dissection such as penetrated aortic ulcer (n = 12), residual Type A aortic dissection (n = 6) and trauma (n = 12) (Table 1). Table 1: Demographics and comorbidities in patients undergoing TEVAR for ACTBAD and CCTBAD   Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Total population   Age (years), mean ± SD  62.3 ± 11.1  61.0 ± 14.0  63.9 ± 7.9     Male, n (%)  40 (81.6)  20 (76.9)  20 (87.0)  0.37   Onset, mean ± SD    6.0 ± 4.3  597.9 ± 334.1    Comorbidities, n (%)   Hypertension  42 (85.7)  24 (92.3)  18 (78.2)  0.75   Smoking  12 (24.5)  6 (23.0)  6 (26.0)  0.63   COPD  6 (12.2)  3 (11.5)  3 (13.0)  0.71   CKD  15 (30.6)  8 (30.7)  7 (30.4)  0.82   CAD  9 (18.4)  5 (19.2)  4 (17.3)  0.90   PAOD  3 (6.1)  2 (7.7)  1 (4.3)  0.77   CVA  5 (10.2)  3 (11.5)  2 (8.6)  0.91   DM  5 (10.2)  3 (11.5)  2 (8.6)  0.86  Medication, n (%)   Antiplatelet  16 (32.7)  10 (38.4)  6 (26.0)  0.36   Anticoagulant  9 (18.4)  4 (15.3)  5 (21.7)  0.58   Statin  9 (18.4)  4 (15.3)  5 (21.7)  0.58  Indications for surgery, n (%)   Aneurysmal rupture  20 (40.8)  20 (76.9)  0     Malperfusion  4 (8.2)  4 (15.4)  0     Persistent back pain  1 (2)  1 (3.8)  0     Refractory hypertension  1 (2)  1 (3.8)  0     Large aneurysm (>6 cm)  20 (40.8)  0  20 (87)     Rapid growth  3 (6.1)  0  3 (13)      Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Total population   Age (years), mean ± SD  62.3 ± 11.1  61.0 ± 14.0  63.9 ± 7.9     Male, n (%)  40 (81.6)  20 (76.9)  20 (87.0)  0.37   Onset, mean ± SD    6.0 ± 4.3  597.9 ± 334.1    Comorbidities, n (%)   Hypertension  42 (85.7)  24 (92.3)  18 (78.2)  0.75   Smoking  12 (24.5)  6 (23.0)  6 (26.0)  0.63   COPD  6 (12.2)  3 (11.5)  3 (13.0)  0.71   CKD  15 (30.6)  8 (30.7)  7 (30.4)  0.82   CAD  9 (18.4)  5 (19.2)  4 (17.3)  0.90   PAOD  3 (6.1)  2 (7.7)  1 (4.3)  0.77   CVA  5 (10.2)  3 (11.5)  2 (8.6)  0.91   DM  5 (10.2)  3 (11.5)  2 (8.6)  0.86  Medication, n (%)   Antiplatelet  16 (32.7)  10 (38.4)  6 (26.0)  0.36   Anticoagulant  9 (18.4)  4 (15.3)  5 (21.7)  0.58   Statin  9 (18.4)  4 (15.3)  5 (21.7)  0.58  Indications for surgery, n (%)   Aneurysmal rupture  20 (40.8)  20 (76.9)  0     Malperfusion  4 (8.2)  4 (15.4)  0     Persistent back pain  1 (2)  1 (3.8)  0     Refractory hypertension  1 (2)  1 (3.8)  0     Large aneurysm (>6 cm)  20 (40.8)  0  20 (87)     Rapid growth  3 (6.1)  0  3 (13)    ACTBAD: acute complicated Type B aortic dissection; CAD: coronary artery disease; CCTBAD: chronic complicated Type B aortic dissection; CKD: chronic kidney disease, (Cr >2.0 mg/dl); COPD: chronic obstructive pulmonary disease; CVA: cerebral vascular accident; DM: diabetes mellitus; PAOD: peripheral artery occlusive disorder; SD: standard deviation; TEVAR: thoracic endovascular aortic repair. Table 1: Demographics and comorbidities in patients undergoing TEVAR for ACTBAD and CCTBAD   Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Total population   Age (years), mean ± SD  62.3 ± 11.1  61.0 ± 14.0  63.9 ± 7.9     Male, n (%)  40 (81.6)  20 (76.9)  20 (87.0)  0.37   Onset, mean ± SD    6.0 ± 4.3  597.9 ± 334.1    Comorbidities, n (%)   Hypertension  42 (85.7)  24 (92.3)  18 (78.2)  0.75   Smoking  12 (24.5)  6 (23.0)  6 (26.0)  0.63   COPD  6 (12.2)  3 (11.5)  3 (13.0)  0.71   CKD  15 (30.6)  8 (30.7)  7 (30.4)  0.82   CAD  9 (18.4)  5 (19.2)  4 (17.3)  0.90   PAOD  3 (6.1)  2 (7.7)  1 (4.3)  0.77   CVA  5 (10.2)  3 (11.5)  2 (8.6)  0.91   DM  5 (10.2)  3 (11.5)  2 (8.6)  0.86  Medication, n (%)   Antiplatelet  16 (32.7)  10 (38.4)  6 (26.0)  0.36   Anticoagulant  9 (18.4)  4 (15.3)  5 (21.7)  0.58   Statin  9 (18.4)  4 (15.3)  5 (21.7)  0.58  Indications for surgery, n (%)   Aneurysmal rupture  20 (40.8)  20 (76.9)  0     Malperfusion  4 (8.2)  4 (15.4)  0     Persistent back pain  1 (2)  1 (3.8)  0     Refractory hypertension  1 (2)  1 (3.8)  0     Large aneurysm (>6 cm)  20 (40.8)  0  20 (87)     Rapid growth  3 (6.1)  0  3 (13)      Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Total population   Age (years), mean ± SD  62.3 ± 11.1  61.0 ± 14.0  63.9 ± 7.9     Male, n (%)  40 (81.6)  20 (76.9)  20 (87.0)  0.37   Onset, mean ± SD    6.0 ± 4.3  597.9 ± 334.1    Comorbidities, n (%)   Hypertension  42 (85.7)  24 (92.3)  18 (78.2)  0.75   Smoking  12 (24.5)  6 (23.0)  6 (26.0)  0.63   COPD  6 (12.2)  3 (11.5)  3 (13.0)  0.71   CKD  15 (30.6)  8 (30.7)  7 (30.4)  0.82   CAD  9 (18.4)  5 (19.2)  4 (17.3)  0.90   PAOD  3 (6.1)  2 (7.7)  1 (4.3)  0.77   CVA  5 (10.2)  3 (11.5)  2 (8.6)  0.91   DM  5 (10.2)  3 (11.5)  2 (8.6)  0.86  Medication, n (%)   Antiplatelet  16 (32.7)  10 (38.4)  6 (26.0)  0.36   Anticoagulant  9 (18.4)  4 (15.3)  5 (21.7)  0.58   Statin  9 (18.4)  4 (15.3)  5 (21.7)  0.58  Indications for surgery, n (%)   Aneurysmal rupture  20 (40.8)  20 (76.9)  0     Malperfusion  4 (8.2)  4 (15.4)  0     Persistent back pain  1 (2)  1 (3.8)  0     Refractory hypertension  1 (2)  1 (3.8)  0     Large aneurysm (>6 cm)  20 (40.8)  0  20 (87)     Rapid growth  3 (6.1)  0  3 (13)    ACTBAD: acute complicated Type B aortic dissection; CAD: coronary artery disease; CCTBAD: chronic complicated Type B aortic dissection; CKD: chronic kidney disease, (Cr >2.0 mg/dl); COPD: chronic obstructive pulmonary disease; CVA: cerebral vascular accident; DM: diabetes mellitus; PAOD: peripheral artery occlusive disorder; SD: standard deviation; TEVAR: thoracic endovascular aortic repair. The patient’s mean age was 62.3 ± 11.1 years. Forty (81.6%) patients were male, and 42 (85.7%) patients had a history of hypertension. The interval of TEVAR for ACTBAD and CCTBAD were 6.0 ± 4.3 and 597.9 ± 334.1 days, respectively. The indications for TEVAR in 26 patients with ACTBAD were aneurysmal rupture in 20 (76.9%) patients, visceral or lower extremities malperfusion in 4 (15.4%) patients, persistent back pain in 1 (3.8%) patient and refractory hypertension in 1 (3.8%) patient. Of the 23 patients with CCTBAD, 21 (91.3%) patients had aneurysmal degeneration with an aortic diameter of more than 6 cm, and 2 (8.7%) patients had rapid aneurysmal growth (aneurysm expansion of aneurysm more than 0.5 cm within 0.5 year). All patients received TEVAR under general anaesthesia except 1 patient with a ruptured ACTBAD who received emergency TEVAR by percutaneous puncture under local anaesthesia. Spinal drainage was performed in 2 patients with ACTBAD and 1 patient with CCTBAD. The mean proximal endovascular graft diameter was similar in both the acute and chronic settings (38.2 ± 3.2 vs 36.7 ± 3.9 mm, P = 0.15). However, the distal endovascular graft diameter was significantly smaller in CCTBAD (35.7 ± 3.6 vs 33.5 ± 4.3 mm, P = 0.048). The percentage of tapered stent grafts did not differ between the 2 groups. The mean contrast usage, procedure and fluoroscopic time were the same in both groups. The planned site of the proximal endovascular graft necessitated additional procedures in 34 (69.4%) patients (ACTBAD: 14, CCTBAD: 20). LSCA revascularization was more frequently performed by a left carotid–subclavian bypass in CCTBAD and by chimney grafts in ACTBAD (34.7% vs 7.7%, P = 0.024). The LSCA was totally covered in 4 (8.2%) patients (ACTBAD: 2, CCTBAD: 2). The number of patients with proximal landing zones in Zone 0 were 2 in CCTBAD, 8 in Zone 1 (ACTBAD: 3, CCTBAD: 5), 28 in Zone 2 (ACTBAD: 15, CCTBAD: 13) and 11 in Zones 3 and 4 (ACTBAD: 8, CCTBAD: 3). Thirty-six (73.5%, ACTBAD: 21, CCTBAD: 15, P = 0.23) patients had aortic coverage above the T6 level and 13 (26.5%, ACTBAD: 5, CCTBAD: 8, P = 0.88) patients down to the coeliac level (Table 2). Additional procedure details are listed in Table 2. Table 2: Procedure data for ACTBAD and CCTBAD   Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Stent graft   Proximal (mm), mean ± SD  37.5 ± 3.53  38.2 ± 3.2  36.7 ± 3.9  0.15   Distal (mm), mean ± SD  34.67 ± 3.93  35.7 ± 3.6  33.5 ± 4.3  0.048   Tapered, n (%)  17 (34.7)  11 (42.3)  6 (26.1)  0.24  Associated procedures, n (%)   Left C-S bypass  10 (20.4)  2 (7.7)  8 (34.7)  0.024   VA transposition  1 (2)  0  1 (4.3)  0.33   C-C-S bypass  6 (12.2)  2 (7.7)  4 (17.7)  0.32   Left SCA chimney  13 (26.5)  10 (38.5)  3 (13.0)  0.041   Left CCA chimney  2 (4.1)  0  2 (8.7)  0.16   Supra-aortic debranching  1 (2)  0  1 (4.3)  0.33   Elephant trunk  1 (2)  0  1 (4.3)  0.33  Procedure details   General anaesthesia, n (%)  48 (98)  25 (96.1)  23 (100)  0.33   CSF drainage, n (%)  3 (6)  2 (7.7)  1 (4.3)  0.63   Left SCA coverage, n (%)  4 (8.1)  2 (7.7)  2 (8.7)  0.90   Percutaneous, n (%)  1 (2)  1 (3.8)  0  0.33   Operation time (min), mean ± SD  272.5 ± 155.6  260.2 ± 128.9  286.4 ± 185.8  0.55   Contrast medium (ml), mean ± SD  265.7 ± 174.83  276.9 ± 229.8  253.0 ± 112.7  0.61   Fluoroscopic time (min), mean ± SD  20.6 ± 14.3  22.1 ± 17.3  18.9 ± 10.9  0.39  Stent graft type, n (%)        0.64   TAG  22 (44.9)  10 (38.4)  12 (52.1)     Zenith  14 (28.6)  9 (34.6)  5 (21.7)     Talent  2 (4)  1 (3.8)  1 (4.3)     Valiant  10 (20.4)  6 (23.0)  4 (17.3)     Relay  1 (2)  0  1 (4.3)    Length of aortic coveragea, n (%)        0.22   Type A  36 (73.5)  21 (80.7)  15 (65.2)     Type B  13 (26.5)  5 (19.3)  8 (34.8)    Proximal landing zone, n (%)        0.31   0  2 (4)  0  2 (8.7)     1  8 (16.3)  3 (11.5)  5 (21.7)     2  28 (57.1)  15 (57.7)  13 (56.5)     3  7 (14.3)  5 (19.2)  2 (8.7)     4  4 (8.1)  3 (11.5)  1 (4.3)      Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Stent graft   Proximal (mm), mean ± SD  37.5 ± 3.53  38.2 ± 3.2  36.7 ± 3.9  0.15   Distal (mm), mean ± SD  34.67 ± 3.93  35.7 ± 3.6  33.5 ± 4.3  0.048   Tapered, n (%)  17 (34.7)  11 (42.3)  6 (26.1)  0.24  Associated procedures, n (%)   Left C-S bypass  10 (20.4)  2 (7.7)  8 (34.7)  0.024   VA transposition  1 (2)  0  1 (4.3)  0.33   C-C-S bypass  6 (12.2)  2 (7.7)  4 (17.7)  0.32   Left SCA chimney  13 (26.5)  10 (38.5)  3 (13.0)  0.041   Left CCA chimney  2 (4.1)  0  2 (8.7)  0.16   Supra-aortic debranching  1 (2)  0  1 (4.3)  0.33   Elephant trunk  1 (2)  0  1 (4.3)  0.33  Procedure details   General anaesthesia, n (%)  48 (98)  25 (96.1)  23 (100)  0.33   CSF drainage, n (%)  3 (6)  2 (7.7)  1 (4.3)  0.63   Left SCA coverage, n (%)  4 (8.1)  2 (7.7)  2 (8.7)  0.90   Percutaneous, n (%)  1 (2)  1 (3.8)  0  0.33   Operation time (min), mean ± SD  272.5 ± 155.6  260.2 ± 128.9  286.4 ± 185.8  0.55   Contrast medium (ml), mean ± SD  265.7 ± 174.83  276.9 ± 229.8  253.0 ± 112.7  0.61   Fluoroscopic time (min), mean ± SD  20.6 ± 14.3  22.1 ± 17.3  18.9 ± 10.9  0.39  Stent graft type, n (%)        0.64   TAG  22 (44.9)  10 (38.4)  12 (52.1)     Zenith  14 (28.6)  9 (34.6)  5 (21.7)     Talent  2 (4)  1 (3.8)  1 (4.3)     Valiant  10 (20.4)  6 (23.0)  4 (17.3)     Relay  1 (2)  0  1 (4.3)    Length of aortic coveragea, n (%)        0.22   Type A  36 (73.5)  21 (80.7)  15 (65.2)     Type B  13 (26.5)  5 (19.3)  8 (34.8)    Proximal landing zone, n (%)        0.31   0  2 (4)  0  2 (8.7)     1  8 (16.3)  3 (11.5)  5 (21.7)     2  28 (57.1)  15 (57.7)  13 (56.5)     3  7 (14.3)  5 (19.2)  2 (8.7)     4  4 (8.1)  3 (11.5)  1 (4.3)    a Length of aortic coverage: Type A: LSCA to T6, Type B: LSCA to coeliac axis. ACTBAD: acute complicated Type B aortic dissection; CCA: common carotid artery; CCTBAD: chronic complicated Type B aortic dissection; C-C-S: carotid-carotid-subclavian; C-S: carotid-subclavian; CSF: cerebrospinal fluid; LSCA: left subclavian artery; SCA: subclavian artery; SD: standard deviation; VA: vertebral artery. Table 2: Procedure data for ACTBAD and CCTBAD   Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Stent graft   Proximal (mm), mean ± SD  37.5 ± 3.53  38.2 ± 3.2  36.7 ± 3.9  0.15   Distal (mm), mean ± SD  34.67 ± 3.93  35.7 ± 3.6  33.5 ± 4.3  0.048   Tapered, n (%)  17 (34.7)  11 (42.3)  6 (26.1)  0.24  Associated procedures, n (%)   Left C-S bypass  10 (20.4)  2 (7.7)  8 (34.7)  0.024   VA transposition  1 (2)  0  1 (4.3)  0.33   C-C-S bypass  6 (12.2)  2 (7.7)  4 (17.7)  0.32   Left SCA chimney  13 (26.5)  10 (38.5)  3 (13.0)  0.041   Left CCA chimney  2 (4.1)  0  2 (8.7)  0.16   Supra-aortic debranching  1 (2)  0  1 (4.3)  0.33   Elephant trunk  1 (2)  0  1 (4.3)  0.33  Procedure details   General anaesthesia, n (%)  48 (98)  25 (96.1)  23 (100)  0.33   CSF drainage, n (%)  3 (6)  2 (7.7)  1 (4.3)  0.63   Left SCA coverage, n (%)  4 (8.1)  2 (7.7)  2 (8.7)  0.90   Percutaneous, n (%)  1 (2)  1 (3.8)  0  0.33   Operation time (min), mean ± SD  272.5 ± 155.6  260.2 ± 128.9  286.4 ± 185.8  0.55   Contrast medium (ml), mean ± SD  265.7 ± 174.83  276.9 ± 229.8  253.0 ± 112.7  0.61   Fluoroscopic time (min), mean ± SD  20.6 ± 14.3  22.1 ± 17.3  18.9 ± 10.9  0.39  Stent graft type, n (%)        0.64   TAG  22 (44.9)  10 (38.4)  12 (52.1)     Zenith  14 (28.6)  9 (34.6)  5 (21.7)     Talent  2 (4)  1 (3.8)  1 (4.3)     Valiant  10 (20.4)  6 (23.0)  4 (17.3)     Relay  1 (2)  0  1 (4.3)    Length of aortic coveragea, n (%)        0.22   Type A  36 (73.5)  21 (80.7)  15 (65.2)     Type B  13 (26.5)  5 (19.3)  8 (34.8)    Proximal landing zone, n (%)        0.31   0  2 (4)  0  2 (8.7)     1  8 (16.3)  3 (11.5)  5 (21.7)     2  28 (57.1)  15 (57.7)  13 (56.5)     3  7 (14.3)  5 (19.2)  2 (8.7)     4  4 (8.1)  3 (11.5)  1 (4.3)      Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Stent graft   Proximal (mm), mean ± SD  37.5 ± 3.53  38.2 ± 3.2  36.7 ± 3.9  0.15   Distal (mm), mean ± SD  34.67 ± 3.93  35.7 ± 3.6  33.5 ± 4.3  0.048   Tapered, n (%)  17 (34.7)  11 (42.3)  6 (26.1)  0.24  Associated procedures, n (%)   Left C-S bypass  10 (20.4)  2 (7.7)  8 (34.7)  0.024   VA transposition  1 (2)  0  1 (4.3)  0.33   C-C-S bypass  6 (12.2)  2 (7.7)  4 (17.7)  0.32   Left SCA chimney  13 (26.5)  10 (38.5)  3 (13.0)  0.041   Left CCA chimney  2 (4.1)  0  2 (8.7)  0.16   Supra-aortic debranching  1 (2)  0  1 (4.3)  0.33   Elephant trunk  1 (2)  0  1 (4.3)  0.33  Procedure details   General anaesthesia, n (%)  48 (98)  25 (96.1)  23 (100)  0.33   CSF drainage, n (%)  3 (6)  2 (7.7)  1 (4.3)  0.63   Left SCA coverage, n (%)  4 (8.1)  2 (7.7)  2 (8.7)  0.90   Percutaneous, n (%)  1 (2)  1 (3.8)  0  0.33   Operation time (min), mean ± SD  272.5 ± 155.6  260.2 ± 128.9  286.4 ± 185.8  0.55   Contrast medium (ml), mean ± SD  265.7 ± 174.83  276.9 ± 229.8  253.0 ± 112.7  0.61   Fluoroscopic time (min), mean ± SD  20.6 ± 14.3  22.1 ± 17.3  18.9 ± 10.9  0.39  Stent graft type, n (%)        0.64   TAG  22 (44.9)  10 (38.4)  12 (52.1)     Zenith  14 (28.6)  9 (34.6)  5 (21.7)     Talent  2 (4)  1 (3.8)  1 (4.3)     Valiant  10 (20.4)  6 (23.0)  4 (17.3)     Relay  1 (2)  0  1 (4.3)    Length of aortic coveragea, n (%)        0.22   Type A  36 (73.5)  21 (80.7)  15 (65.2)     Type B  13 (26.5)  5 (19.3)  8 (34.8)    Proximal landing zone, n (%)        0.31   0  2 (4)  0  2 (8.7)     1  8 (16.3)  3 (11.5)  5 (21.7)     2  28 (57.1)  15 (57.7)  13 (56.5)     3  7 (14.3)  5 (19.2)  2 (8.7)     4  4 (8.1)  3 (11.5)  1 (4.3)    a Length of aortic coverage: Type A: LSCA to T6, Type B: LSCA to coeliac axis. ACTBAD: acute complicated Type B aortic dissection; CCA: common carotid artery; CCTBAD: chronic complicated Type B aortic dissection; C-C-S: carotid-carotid-subclavian; C-S: carotid-subclavian; CSF: cerebrospinal fluid; LSCA: left subclavian artery; SCA: subclavian artery; SD: standard deviation; VA: vertebral artery. Thirty-day morbidity and mortality TEVAR was successful in all 49 patients. There were 2 deaths within 30 days in the acute group (7.7%) and none in the chronic group. In the acute group, 1 patient died of persistent bleeding even after a salvage TEVAR was performed for acute aortic rupture and the other from a delayed retrograde Type A dissection 1 week after the TEVAR procedure with a proximal bare metal stent graft. There was no stroke in either group. However, 2 patients developed paraplegia, 1 in each group. Temporary haemodialysis was required in 2 cases (4.0%). Other procedure-related complications included myocardial infarction (6.0%), pneumonia (4.0%) and vascular access bleeding (4.0%). There was no difference in 30-day mortality and complications between the acute and chronic groups (Table 3). Table 3: Surgical results and complications   Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Technical success, n (%)  49 (100)  26 (100)  23 (100)  0.99  30-Day mortality, n (%)  2 (4)  2 (7.7)  0  0.16  Procedure-related complication, n (%)   Paraplegia  2 (4)  1 (3.8)  1 (4.3)  0.93   CVA  0  0  0     MI  3 (6)  2 (7.7)  1 (4.3)  0.63   Pneumonia  2 (4)  1 (3.8)  1 (4.3)  0.93   Renal insufficiency  7 (14.3)  4 (15.4)  3 (13)  0.81    Without H/D  5  3  2      Temporary H/D  2  1  1      Long term H/D  0  0  0     Distal limb ischaemia  0  0  0  –   Vascular access bleeding  2 (4)  1 (3.8)  1 (4.3)  0.93  Device-related complications, n (%)   Proximal SINE  2 (4)  2 (7.7)  0  0.16    Immediate  1  1  0  0.33    Delayed  1  1  0  0.33   Distal SINE  1 (2)  1 (4.1)  0 (0)  0.33    Immediate  0  0  0      Delayed  1  1    0.33  Endoleak, n (%)        0.91   Type I  2 (4.0)  1 (3.8)  1 (4.3)     Type II (Non-LSCA)  3 (6)  2 (7.7)  1 (4.3)     Type II (LSCA)  2 (4)  1 (3.8)  1 (4.3)     Type III  0  0  0     Type IV  0  0  0    Extent of FL thrombosisa, n (%)        0.12   0  7 (14.9%)  1 (4.2%)  6 (26.0%)     I  11 (23.4%)  7 (29.1%)  4 (15.3%)     II  17 (36.1%)  8 (33.3%)  9 (39.1%)     III  12 (25.5%)  8 (33.3%)  4 (17.3%)      Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Technical success, n (%)  49 (100)  26 (100)  23 (100)  0.99  30-Day mortality, n (%)  2 (4)  2 (7.7)  0  0.16  Procedure-related complication, n (%)   Paraplegia  2 (4)  1 (3.8)  1 (4.3)  0.93   CVA  0  0  0     MI  3 (6)  2 (7.7)  1 (4.3)  0.63   Pneumonia  2 (4)  1 (3.8)  1 (4.3)  0.93   Renal insufficiency  7 (14.3)  4 (15.4)  3 (13)  0.81    Without H/D  5  3  2      Temporary H/D  2  1  1      Long term H/D  0  0  0     Distal limb ischaemia  0  0  0  –   Vascular access bleeding  2 (4)  1 (3.8)  1 (4.3)  0.93  Device-related complications, n (%)   Proximal SINE  2 (4)  2 (7.7)  0  0.16    Immediate  1  1  0  0.33    Delayed  1  1  0  0.33   Distal SINE  1 (2)  1 (4.1)  0 (0)  0.33    Immediate  0  0  0      Delayed  1  1    0.33  Endoleak, n (%)        0.91   Type I  2 (4.0)  1 (3.8)  1 (4.3)     Type II (Non-LSCA)  3 (6)  2 (7.7)  1 (4.3)     Type II (LSCA)  2 (4)  1 (3.8)  1 (4.3)     Type III  0  0  0     Type IV  0  0  0    Extent of FL thrombosisa, n (%)        0.12   0  7 (14.9%)  1 (4.2%)  6 (26.0%)     I  11 (23.4%)  7 (29.1%)  4 (15.3%)     II  17 (36.1%)  8 (33.3%)  9 (39.1%)     III  12 (25.5%)  8 (33.3%)  4 (17.3%)    a 0: some retrograde FL perfusion along stent graft; I: FL thrombosis along the stent graft; II: FL thrombosis to the coeliac artery; III: complete FL thrombosis. The false lumen thrombosis was analysed for 47 patients because 2 in-hospital death were excluded. ACTBAD: acute complicated Type B aortic dissection; CCTBAD: chronic complicated Type B aortic dissection; FL: false lumen; H/D: haemodialysis; LSCA: left subclavian artery; MI: myocardial infarction; SINE: stent graft-induced new entry. Table 3: Surgical results and complications   Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Technical success, n (%)  49 (100)  26 (100)  23 (100)  0.99  30-Day mortality, n (%)  2 (4)  2 (7.7)  0  0.16  Procedure-related complication, n (%)   Paraplegia  2 (4)  1 (3.8)  1 (4.3)  0.93   CVA  0  0  0     MI  3 (6)  2 (7.7)  1 (4.3)  0.63   Pneumonia  2 (4)  1 (3.8)  1 (4.3)  0.93   Renal insufficiency  7 (14.3)  4 (15.4)  3 (13)  0.81    Without H/D  5  3  2      Temporary H/D  2  1  1      Long term H/D  0  0  0     Distal limb ischaemia  0  0  0  –   Vascular access bleeding  2 (4)  1 (3.8)  1 (4.3)  0.93  Device-related complications, n (%)   Proximal SINE  2 (4)  2 (7.7)  0  0.16    Immediate  1  1  0  0.33    Delayed  1  1  0  0.33   Distal SINE  1 (2)  1 (4.1)  0 (0)  0.33    Immediate  0  0  0      Delayed  1  1    0.33  Endoleak, n (%)        0.91   Type I  2 (4.0)  1 (3.8)  1 (4.3)     Type II (Non-LSCA)  3 (6)  2 (7.7)  1 (4.3)     Type II (LSCA)  2 (4)  1 (3.8)  1 (4.3)     Type III  0  0  0     Type IV  0  0  0    Extent of FL thrombosisa, n (%)        0.12   0  7 (14.9%)  1 (4.2%)  6 (26.0%)     I  11 (23.4%)  7 (29.1%)  4 (15.3%)     II  17 (36.1%)  8 (33.3%)  9 (39.1%)     III  12 (25.5%)  8 (33.3%)  4 (17.3%)      Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Technical success, n (%)  49 (100)  26 (100)  23 (100)  0.99  30-Day mortality, n (%)  2 (4)  2 (7.7)  0  0.16  Procedure-related complication, n (%)   Paraplegia  2 (4)  1 (3.8)  1 (4.3)  0.93   CVA  0  0  0     MI  3 (6)  2 (7.7)  1 (4.3)  0.63   Pneumonia  2 (4)  1 (3.8)  1 (4.3)  0.93   Renal insufficiency  7 (14.3)  4 (15.4)  3 (13)  0.81    Without H/D  5  3  2      Temporary H/D  2  1  1      Long term H/D  0  0  0     Distal limb ischaemia  0  0  0  –   Vascular access bleeding  2 (4)  1 (3.8)  1 (4.3)  0.93  Device-related complications, n (%)   Proximal SINE  2 (4)  2 (7.7)  0  0.16    Immediate  1  1  0  0.33    Delayed  1  1  0  0.33   Distal SINE  1 (2)  1 (4.1)  0 (0)  0.33    Immediate  0  0  0      Delayed  1  1    0.33  Endoleak, n (%)        0.91   Type I  2 (4.0)  1 (3.8)  1 (4.3)     Type II (Non-LSCA)  3 (6)  2 (7.7)  1 (4.3)     Type II (LSCA)  2 (4)  1 (3.8)  1 (4.3)     Type III  0  0  0     Type IV  0  0  0    Extent of FL thrombosisa, n (%)        0.12   0  7 (14.9%)  1 (4.2%)  6 (26.0%)     I  11 (23.4%)  7 (29.1%)  4 (15.3%)     II  17 (36.1%)  8 (33.3%)  9 (39.1%)     III  12 (25.5%)  8 (33.3%)  4 (17.3%)    a 0: some retrograde FL perfusion along stent graft; I: FL thrombosis along the stent graft; II: FL thrombosis to the coeliac artery; III: complete FL thrombosis. The false lumen thrombosis was analysed for 47 patients because 2 in-hospital death were excluded. ACTBAD: acute complicated Type B aortic dissection; CCTBAD: chronic complicated Type B aortic dissection; FL: false lumen; H/D: haemodialysis; LSCA: left subclavian artery; MI: myocardial infarction; SINE: stent graft-induced new entry. Follow-up outcome The mean follow-up period was 27.5 ± 19.1 months in ACTBAD and 22.3 ± 10.9 months in CCTBAD, respectively. Six patients succumbed during the follow-up period (3 in each group). There was no difference in the cumulative freedom from all-cause mortality (ACTBAD: 77.6%, CCTBAD: 68.8%, P = 0.76) and aneurysmal-related mortality (ACTBAD: 88.2%, CCTBAD: 95.0%, P = 0.64) (Fig. 2A and B) between the 2 groups. One patient with ACTBAD died of an aorto-oesophageal fistula due to a late prosthetic infection 20 months after TEVAR. The other 2 died of terminal pancreatic cancer and a large cerebral infarction 22 and 28 months into the follow-up period, respectively. In the chronic group, 1 patient died of aortic rupture 1 month after discharge due to ongoing retrograde perfusion from the distal intimal tear in the non-stented aorta. The remaining 2 patients died of multiple organ failure after 32 and 36 months of follow-up. The cumulative freedom from reintervention rate of both groups were similar during the follow-up (ACTBAD: 92.3%, CCTBAD: 95.6%, P = 0.94) (Fig. 2C). Three patients required reintervention (ACTBAD: 2, CCTBAD: 1). In the acute setting, 1 patient required a secondary procedure for continued proximal aneurysmal enlargement due to a late Type I endovascular leak after 48 months of follow-up, and the other developed a distal stent graft-induced new entry (SINE) requiring an additional distal endograft extension 50 months after TEVAR. In the chronic cohort, 1 patient required a hybrid procedure with a retrograde visceral bypass and a thoracoabdominal stent graft due to persistent aneurysm formation in the abdominal aorta 21 months after TEVAR. During the follow-up, 5 patients who had persistent Type II endoleak required no intervention. No chimney graft (LSCA chimney: 13; LCCA chimney: 2) occlusion was detected. Figure 2: View largeDownload slide Actuarial (Kaplan–Meier) freedom from all-cause mortality (A), aneurysmal-related mortality (B) and reintervention (C). The numbers above the x-axis are the number of patients at risk. The P-value is calculated by the log-rank test. Figure 2: View largeDownload slide Actuarial (Kaplan–Meier) freedom from all-cause mortality (A), aneurysmal-related mortality (B) and reintervention (C). The numbers above the x-axis are the number of patients at risk. The P-value is calculated by the log-rank test. Aortic remodelling The extent of FL thrombosis after TEVAR was evaluated based on the latest CT scan of each patient, except for the 2 patients who died within 30 days after surgery in the acute group (Table 3). Overall, 12 (25.5%) patients experienced complete FL thrombosis along the whole aorta (ACTBAD: 8, CCTBAD: 4, P = 0.28). Seven (14.9%) patients continued to have some FL retrograde flow through a distal fenestration along the endovascular graft (ACTBAD: 1, CCTBAD: 6, P = 0.036). In summary, 35 (75.5%) patients still experienced FL flow in the abdominal aorta below the coeliac artery (ACTBAD: 16, CCTBAD: 19, P = 0.10). To check for any significant diameter changes of the TL and FL at the 6 aortic levels after endograft surgery, the cases were pooled and investigated together to determine the effects of acute versus chronic and the level of distal stent graft deployment on aortic remodelling. Significant increase in the TL diameter and decrease in the FL diameter at levels A, B and C (P < 0.001) were noted during the follow-up in both groups (Fig. 3). Following TEVAR, there was no significant difference in the TL expansion or the FL regression at 6 levels between the ACTBAD and CCTBAD groups (Fig. 4). When patients were stratified by the extent of the thoracic aortic coverage, no difference was found between ACTBAD and CCTBAD (Fig. 5). Figure 3: View largeDownload slide Periodic changes in true lumen and false lumen diameters for all complicated Type B aortic dissection at 6 aortic levels (A–F) recorded before (0), 1 month (1) and 1 year after TEVAR (2). The bars stand for mean ± standard error. The P-value indicates whether the time effect is significant for each lumen. TEVAR: thoracic endovascular aortic repair. Figure 3: View largeDownload slide Periodic changes in true lumen and false lumen diameters for all complicated Type B aortic dissection at 6 aortic levels (A–F) recorded before (0), 1 month (1) and 1 year after TEVAR (2). The bars stand for mean ± standard error. The P-value indicates whether the time effect is significant for each lumen. TEVAR: thoracic endovascular aortic repair. Figure 4: View largeDownload slide Periodic changes in true lumen (left panel) and false lumen (right panel) diameters at 6 aortic levels (A–F) between ACCTBAD and CCTBAD recorded before (0), 1 month (1) and 1 year after TEVAR (2). The bars stand for mean ± standard error. The P-value indicates whether the interaction effect between group (chronic and acute) and time is significant for each aortic level. ACTBAD: acute complicated Type B aortic dissection; CCTBAD: chronic complicated Type B aortic dissection; TEVAR: thoracic endovascular aortic repair. Figure 4: View largeDownload slide Periodic changes in true lumen (left panel) and false lumen (right panel) diameters at 6 aortic levels (A–F) between ACCTBAD and CCTBAD recorded before (0), 1 month (1) and 1 year after TEVAR (2). The bars stand for mean ± standard error. The P-value indicates whether the interaction effect between group (chronic and acute) and time is significant for each aortic level. ACTBAD: acute complicated Type B aortic dissection; CCTBAD: chronic complicated Type B aortic dissection; TEVAR: thoracic endovascular aortic repair. Figure 5: View largeDownload slide Periodic changes in true lumen (left panel) and false lumen (right panel) diameters at 6 aortic levels (A–F) between aortic coverage above and below T6 level recorded before (0), 1 month (1) and 1 year after TEVAR (2). The bars stand for mean ± standard error. The P-value indicates whether the interaction effect between group (above T6 and below T6) and time is significant for each aortic level. Figure 5: View largeDownload slide Periodic changes in true lumen (left panel) and false lumen (right panel) diameters at 6 aortic levels (A–F) between aortic coverage above and below T6 level recorded before (0), 1 month (1) and 1 year after TEVAR (2). The bars stand for mean ± standard error. The P-value indicates whether the interaction effect between group (above T6 and below T6) and time is significant for each aortic level. DISCUSSION Without early diagnosis and proper treatment, complicated TBAD is a cardiovascular event of high mortality [1, 20]. With the development and technical refinement of endovascular stent grafts, TEVAR has improved the outcome compared to the medical therapy and open surgical repair [9, 20]. Higher major complications and 30-day mortality have been reported in patients with ACTBAD undergoing TEVAR compared to patients with CCTBAD [21]. In our study, the 30-day mortality rates were 7.7% in patients with ACTBAD and 0% in those with CCTBAD, which was comparable with previous reports. However, no difference was found in major complication rates between ACTBAD and CCTBAD. Retrograde Type A dissection was a recognized complication of TEVAR and more frequently occurred in patients with acute disease. One of the deaths with ACTBAD in our study was attributed to the late onset of retrograde Type A dissection. However, the aetiology remained undefined and could have been related to the proximal bare metal stent, aggressive aortic ballooning or oversized stent graft [12]. The neurological complications, including stroke and paraplegia, were low in our study. This could be attributed to the high percentage of LSCA revascularization and short endograft aortic coverage. Ten patients in our study required more proximal landing (Zone 0: 2; Zone 1: 8) to achieve adequate exclusion. No stroke or retrograde Type A dissection occurred in any of these patients. Adjunctive procedures such as the chimney procedure or arch vessel debranching might not necessarily increase the complication rate for TBAD. At the 3-year follow-up, some studies showed a significantly poorer cumulative survival for patients with CCTBAD [22, 23]. However, no difference was found in all-cause mortality (P = 0.7612) and aneurysmal-related mortality (P = 0.64) between the ACTBAD and CCTBAD groups in our study. The reintervention rate during follow-up was also low for both groups (ACTBAD: 7.7%, CCTBAD: 4.3%). It was required in 1 case of proximal and 2 cases of distal aortic aneurysmal events. Oversizing of the stent graft has been reported to be the main risk for proximal or distal SINE [3]. Distal SINE might cause persistent FL perfusion and continuous aneurysmal expansion. In our protocol, we chose the stent graft with a diameter 10–15% larger than the diameter of the intended proximal landing area, and the stent was not intentionally tapered. The incidence of distal SINE in our study was 4.0%, which was similar to that reported in the literature and much lower than that with a stainless-steel-based stent graft [3, 13]. In this study, we did not appreciate the importance of downsizing the stent graft to prevent distal SINE [13]. This complication could be avoided by careful manipulation of the graft without excessive ballooning with current devices. The aim of TEVAR in aortic dissection was to cover the primary entry tear, stabilize the septum and re-establish perfusion to hypoperfused organs [21]. However, heterogeneous descriptions for aortic remodelling including the TL and FL diameters, areas and volumes after TEVAR have been measured. The maximum short axis diameter of both the TL and FL on axial CT images were measured in this study because the absolute diameter or diameter change was still the criterion for intervention in current practice. Aortic remodelling above the coeliac trunk artery was significant (P < 0.001). However, this was not the case below the coeliac trunk and reflected the concerns of TEVAR for TBAD. Coverage of a proximal primary tear alone did not promote distal aortic remodelling because the uncovered distal fenestration led to persistent flow and pressurization of the distal abdominal aorta. There was no significant difference between aortic remodelling in either ACTBAD or CCTBAD at any of the 6 levels. Despite the thickened intimal flap, thoracic aortic remodelling in CCTBAD was still favoured as an acute setting [14, 18]. In most studies, the FL thrombosis rate was similar in patients with ACTBAD and CCTBAD, ranging from 55% to 80%, and the FL thrombosis rate was usually greater at the level of the thoracic stent graft and lower below the diaphragm level [12, 15]. In our study, there were only 12 (25.5%) patients experiencing total FL thrombosis (ACTBAD: 8, CCTBAD: 4, P = 0.23), and 37 (75.5%) patients still experienced patent FL flow in the abdominal aorta. We did not observe any significant difference in FL thrombosis in the abdominal aorta between these 2 groups. However, the rate of persistent proximal FL perfusion along the thoracic stent graft was significantly higher in the CCTBAD group (P = 0.036). Despite the presence of FL flow, some investigators have suggested that TEVAR could still promote perigraft thrombosis. Only 1 patient with CCTBAD required reintervention in the distal abdominal aorta 21 months after TEVAR. However, longer follow-up for the detection of aneurysmal progression in the abdominal aortic segment is still warranted. The other unresolved issue related to TEVAR was the extent of endovascular graft coverage [2, 12]. Extensive coverage could decrease potential retrograde FL flow from downstream fenestration. However, the concern about extensive paving is justified due to the potential compromise of the critical blood supply to the spinal cord. In our study, we did not observe any significant difference in aortic remodelling when stratified by the extent of thoracic aortic coverage. Despite the relatively low rate of paraplegia in our study, we still preferred to cover only half of the length of the thoracic aorta to the extent necessary to relieve the malperfusion, restore the TL flow and prevent the spring-back effect [1]. Nevertheless, in patients presenting with aortic rupture, complete coverage of the entire thoracic aorta was usually required. Limitations The present investigation was conducted as a retrospective intention-to-treat analysis from a single centre. Half of our patients had not been followed up for more than 24 months, including the CT scan follow-up after 1 year. This follow-up period was relatively short for the evaluation of aneurysmal degeneration in the non-stented part of the abdominal aorta, and therefore it was not possible to fully examine the risk of reintervention. Further study with longer follow-up is required to define the association between TEVAR techniques and aortic remodelling, especially related to the abdominal aorta after TEVAR. CONCLUSIONS The early and 3-year follow-up in our study showed that endovascular repair for both ACTBAD and CCTBAD was safe and effective. Aortic remodelling was favourable above the coeliac artery after TEVAR, and no difference was found between ACTBAD and CCTBAD. The length of endograft coverage had no impact on the aortic remodelling. Low rate of FL thrombosis in the abdominal aorta warrants continuous imaging surveillance. Conflict of interest: none declared. REFERENCES 1 Fattori R, Cao P, De Rango P, Czerny M, Evangelista A, Nienaber C et al.   Interdisciplinary expert consensus document on management of type B aortic dissection. J Am Coll Cardiol  2013; 61: 1661– 78. Google Scholar CrossRef Search ADS PubMed  2 Lee M, Lee DY, Kim MD, Lee MS, Won JY, Park SI et al.   Outcomes of endovascular management for complicated chronic type B aortic dissection: effect of the extent of stent graft coverage and anatomic properties of aortic dissection. J Vasc Interv Radiol  2013; 24: 1451– 60. Google Scholar CrossRef Search ADS PubMed  3 Dong ZH, Fu WG, Wang YQ, Guo DQ, Xu X, Ji Y et al.   Retrograde type A aortic dissection after endovascular stent graft placement for treatment of type B dissection. Circulation  2009; 119: 735– 41. Google Scholar CrossRef Search ADS PubMed  4 Chemelli-Steingruber IE, Chemelli A, Strasak A, Hugl B, Hiemetzberger R, Czermak BV. Evaluation of volumetric measurements in patients with acute type B aortic dissection–thoracic endovascular aortic repair (TEVAR) vs conservative. J Vasc Surg  2009; 49: 20– 8. Google Scholar CrossRef Search ADS PubMed  5 Chemelli-Steingruber IE, Chemelli A, Strasak A, Hugl B, Hiemetzberger R, Jaschke W et al.   Endovascular repair or medical treatment of acute type B aortic dissection? A comparison. Eur J Radiol  2010; 73: 175– 80. Google Scholar CrossRef Search ADS PubMed  6 Tsai TT, Fattori R, Trimarchi S, Isselbacher E, Myrmel T, Evangelista A et al.   Long-term survival in patients presenting with type B acute aortic dissection: insights from the International Registry of Acute Aortic Dissection. Circulation  2006; 114: 2226– 31. Google Scholar CrossRef Search ADS PubMed  7 Garbade J, Jenniches M, Borger MA, Barten MJ, Scheinert D, Gutberlet M et al.   Outcome of patients suffering from acute type B aortic dissection: a retrospective single-centre analysis of 135 consecutive patients. Eur J Cardiothorac Surg  2010; 38: 285– 92. Google Scholar CrossRef Search ADS PubMed  8 Fattori R, Tsai TT, Myrmel T, Evangelista A, Cooper JV, Trimarchi S et al.   Complicated acute type B dissection: is surgery still the best option?: a report from the International Registry of Acute Aortic Dissection. JACC Cardiovasc Interv  2008; 1: 395– 402. Google Scholar CrossRef Search ADS PubMed  9 Estrera AL, Miller CC, Goodrick J, Porat EE, Achouh PE, Dhareshwar J et al.   Update on outcomes of acute type B aortic dissection. Ann Thorac Surg  2007; 83: S842– 50. Google Scholar CrossRef Search ADS PubMed  10 Erbel R, Alfonso F, Boileau C, Dirsch O, Eber B, Haverich A et al.   Providentia, diagnosis and management of aortic dissection. Eur Heart J  2001; 22: 1642– 81. Google Scholar CrossRef Search ADS PubMed  11 Swee W, Dake MD. Endovascular management of thoracic dissections. Circulation  2008; 117: 1460– 73. Google Scholar CrossRef Search ADS PubMed  12 Sayer D, Bratby M, Brooks M, Loftus I, Morgan R, Thompson M. Aortic morphology following endovascular repair of acute and chronic type B aortic dissection: implications for management. Eur J Vasc Endovasc Surg  2008; 36: 522– 9. Google Scholar CrossRef Search ADS PubMed  13 Yang CP, Hsu CP, Chen WY, Chen IM, Weng CF, Chen CK et al.   Aortic remodeling after endovascular repair with stainless steel-based stent graft in acute and chronic type B aortic dissection. J Vasc Surg  2012; 55: 1600– 10. Google Scholar CrossRef Search ADS PubMed  14 Sigman MM, Palmer OP, Ham SW, Cunningham M, Weaver FA. Aortic morphologic findings after thoracic endovascular aortic repair for type B aortic dissection. JAMA Surg  2014; 149: 977– 83. Google Scholar CrossRef Search ADS PubMed  15 Parsa CJ, Schroder JN, Daneshmand MA, McCann RL, Hughes GC. Midterm results for endovascular repair of complicated acute and chronic type B aortic dissection. Ann Thorac Surg  2010; 89: 97. Google Scholar CrossRef Search ADS PubMed  16 Criado FJ, Clark NS, Barnatan MF. Stent graft repair in the aortic arch and descending thoracic aorta: a 4-year experience. J Vasc Surg  2002; 36: 1121– 28. Google Scholar CrossRef Search ADS PubMed  17 Conrad MF, Crawford RS, Kwolek CJ, Brewster DC, Brady TJ, Cambria RP. Aortic remodeling after endovascular repair of acute complicated type B aortic dissection. J Vasc Surg  2009; 50: 510– 17. Google Scholar CrossRef Search ADS PubMed  18 Kusagawa H, Shimono T, Ishida M, Suzuki T, Yasuda F, Yuasa U et al.   Changes in false lumen after transluminal stent-graft placement in aortic dissections: six years’ experience. Circulation  2005; 111: 2951– 57. Google Scholar CrossRef Search ADS PubMed  19 Gorlitzer M, Weiss G, Meinhart J, Waldenberger F, Thalmann M, Folkmann S et al.   Fate of the false lumen after combined surgical and endovascular repair treating Stanford type A aortic dissections. Ann Thorac Surg  2010; 89: 794– 99. Google Scholar CrossRef Search ADS PubMed  20 Fattori R, Montgomery D, Lovato L, Kische S, Di Eusanio M, Ince H et al.   Survival after endovascular therapy in patients with type B aortic dissection: a report from the International Registry of Acute Aortic Dissection (IRAD). JACC Cardiovasc Interv  2013; 6: 876– 82. Google Scholar CrossRef Search ADS PubMed  21 Eggebrecht H, Nienaber CA, Neuhauser M, Baumgart D, Kische S, Schmermund A et al.   Endovascular stent-graft placement in aortic dissection: a meta-analysis. Eur Hear J  2006; 27: 489– 98. Google Scholar CrossRef Search ADS   22 Bozinovski J, Coselli JS. Outcomes and survival in surgical treatment of descending thoracic aorta with acute dissection. Ann Thorac Surg  2008; 85: 965– 5. Google Scholar CrossRef Search ADS PubMed  23 Zoli S, Etz CD, Roder F, Mueller CS, Brenner RM, Bodian CA et al.   Long-term survival after open repair of chronic distal aortic dissection. Ann Thorac Surg  2010; 89: 1458– 66. Google Scholar CrossRef Search ADS PubMed  © The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Interactive CardioVascular and Thoracic Surgery Oxford University Press

Comparisons of aortic remodelling and outcomes after endovascular repair of acute and chronic complicated Type B aortic dissections

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Oxford University Press
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© The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
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1569-9293
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Abstract

Abstract OBJECTIVES Patients with acute (ACTBAD) or chronic complicated Type B aortic dissection (CCTBAD) undergoing thoracic endovascular aortic repair (TEVAR) remain at high risk for late aorta-related events. Few data exist on the comparison of aortic remodelling and outcomes after TEVAR between both groups. METHODS Forty-nine patients of TEVAR for CCTBAD (n = 26) and ACTBAD (n = 23) were retrospectively reviewed at our centre. RESULTS The overall 30-day mortality was 4%. Cumulative freedom from all-cause mortality (ACTBAD: 77.6%, CCTBAD: 68.8%; P = 0.76), aneurysmal-related mortality (ACTBAD: 88.2%, CCTBAD: 95.0%; P = 0.63) and the 3-year reintervention rate (ACTBAD: 92.3%, CCTBAD: 95.6%; P = 0.94) were the same in both groups. Aortic remodelling was significant (P < 0.001) above the coeliac level after TEVAR. Thirty-five (75.5%) patients still experienced false lumen flow in the abdominal aorta below the coeliac artery (ACTBAD: 16, CCTBAD: 19, P = 0.10). No difference was found in aortic remodelling between the ACTBAD and CCTBAD groups, and the length of endograft coverage had no impact on the aortic remodelling. CONCLUSIONS The early and 3-year follow-up in our study showed that endovascular repair for both ACTBAD and CCTBAD was safe and effective. Aortic remodelling was favourable above the coeliac artery after TEVAR, and no difference was found between ACTBAD and CCTBAD. The length of endograft coverage had no impact on aortic remodelling. The low rate of false lumen thrombosis in the abdominal aorta warranted continuous imaging surveillance. Aortic remodelling, Aortic dissection, Aortic aneurysm, Endovascular repair, False lumen thrombosis INTRODUCTION The optimal management of Type B aortic dissection (TBAD) remains among the most challenging ongoing investigational issues in thoracic aortic surgery. In uncomplicated cases, a conservative approach with close surveillance seems to be justified if complications develop [1]. In an acute or chronic complicated TBAD, urgent aortic repair is usually required, and thoracic endovascular aneurysm repair (TEVAR) has become the treatment modality of choice since the last decade [2–5]. One of the fundamental concerns between acute complicated TBAD (ACTBAD) and chronic complicated TBAD (CCTBAD) is the fragility of the intimal flap and adventitia that may cause entry tear and subsequent capacity for aortic remodelling after TEVAR [1, 6–10]. Despite the current satisfactory and consistent outcomes, few publications are available that include comparisons of aortic remodelling in the form of false lumen (FL) regression and true lumen (TL) expansion or the reintervention rate for late aortic events between patients having undergone TEVAR for ACTBAD and CCTBAD. The aim of this study was to evaluate 30-day and mid-term outcomes and examine aortic remodelling in thoracic and abdominal aorta in patients having undergone TEVAR for ACTBAD and CCTBAD in our institution. METHODS The research was approved by the institutional review board of the National Taiwan University Hospital Ethics Committee (No. 201403080RIND) as a retrospective cohort study. All the subjects were well informed and gave signed consent. All the clinical procedures and methods were in compliance with the relevant guidelines and regulations. Acute and chronic cases were defined by an elapsed period of less or more than 2 weeks from the onset of symptoms [10–12]. Patients with both acute and chronic complicated TBAD who received TEVAR were included, but patients with connective tissue diseases, atypical aortic dissection such as penetrated aortic ulcer, residual Type A aortic dissection (n = 6) and trauma were excluded. Cerebrospinal fluid drains were inserted depending on a history of previous aortic surgery, the need for left subclavian artery (LSCA) coverage and the anticipated long length of aortic coverage. Endovascular grafts were oversized by 10–15% of the proximally healthy aortic landing zone diameter. Tapered devices or the overlapping tapered technique with additional pieces were selectively used in patients with smaller distal aortic landing zones. To achieve adequate landing and avoid Type 1 endoleak, adjunctive procedures other than stent grafting such as arch vessel debranching were done in some patients as needed [13–17]. Technical success was defined as successful proximal entry tear coverage without conversion to open repair or any Type I endoleak. Follow-up imaging protocols Computerized tomography (CT) was the preferred imaging modality for all patients. CT images were obtained before, at 1 month, 12 months and annually after TEVAR. The maximum diameter of TL and FL in the short axis view (Fig. 1) were accessed at 6 levels: A: the proximal thoracic aorta 2 cm below the LSCA ostium, B: the mid-thoracic aorta at the level of the left inferior pulmonary vein, C: the distal thoracic aorta 2 cm above the diaphragm, D: the coeliac artery, E: the lowest renal arteries, F: the infrarenal aorta at the middle of aortic bifurcation and lowest renal artery using the TeraRecon System (TeraRecon Inc., San Mateo, CA, USA). The procedure details (Table 2) and extent of FL thrombosis (Table 3) were also classified [18, 19]. The changes in TL and FL diameters (TL expansion and FL regression) at the 6 levels between preoperative, 1 month and 12 months were of interest and were checked using a CT scan. The mid-term outcomes included freedom from all-cause and aneurysm-related mortality, and the reintervention rate was analysed. Figure 1: View largeDownload slide Images were obtained at the level of (A) the proximal thoracic aorta 2 cm below the left subclavian artery ostium; (B) the mid-thoracic aorta at the level of the left inferior pulmonary vein; (C) the distal thoracic aorta 2 cm above the diaphragm; (D) the coeliac artery; (E) the lowest renal arteries; (F) the infrarenal aorta at the middle of aortic bifurcation and lowest renal artery. F: FL diameter; T: TL diameter. Figure 1: View largeDownload slide Images were obtained at the level of (A) the proximal thoracic aorta 2 cm below the left subclavian artery ostium; (B) the mid-thoracic aorta at the level of the left inferior pulmonary vein; (C) the distal thoracic aorta 2 cm above the diaphragm; (D) the coeliac artery; (E) the lowest renal arteries; (F) the infrarenal aorta at the middle of aortic bifurcation and lowest renal artery. F: FL diameter; T: TL diameter. Statistical analysis Demographic and periprocedural characteristics were shown as numbers with percentages or as means ± standard deviations. The categorical and continuous variables between the ACTBAD and CTBAD groups were compared by using the Pearson χ2 test and unpaired t-test, respectively. The changes in TL and FL diameters at the 3 time points and the 6 levels of the aorta on CT imaging were presented as means ± standard errors and analysed using the mixed-effects model for longitudinal data. Repeated assessment of each measure was modelled by factors (TL versus FL diameter; ACTBAD versus CCTBAD, aortic coverage above versus below T6 level), time and interaction of factor and time for 6 different positions (a, b, c, d, e and f). A covariance structure was selected first for each model. The justification of covariance structure including 5 different types (unstructured, compound symmetry, variance components, autogressive1, Huynh–Feldt) was compared based on the Akaike information criterion and Schwartz’s Bayesian criterion. Smaller values indicated a better fit. Survival comparisons between the acute and chronic groups were made using the Kaplan–Meier method and the log-rank test. P-values <0.05 were considered statistically significant. All statistical analyses were performed using SAS System Version 9.2 (SAS Institute Inc., Cary, NC, USA). RESULTS Between June 2008 and November 2014, 83 patients with TBAD underwent TEVAR in our institution. The study cohort comprised 49 patients (ACTBAD: 26, CCTBAD: 23) out of 83 patients after exclusion of the patients with connective tissue diseases (n = 4), atypical aortic dissection such as penetrated aortic ulcer (n = 12), residual Type A aortic dissection (n = 6) and trauma (n = 12) (Table 1). Table 1: Demographics and comorbidities in patients undergoing TEVAR for ACTBAD and CCTBAD   Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Total population   Age (years), mean ± SD  62.3 ± 11.1  61.0 ± 14.0  63.9 ± 7.9     Male, n (%)  40 (81.6)  20 (76.9)  20 (87.0)  0.37   Onset, mean ± SD    6.0 ± 4.3  597.9 ± 334.1    Comorbidities, n (%)   Hypertension  42 (85.7)  24 (92.3)  18 (78.2)  0.75   Smoking  12 (24.5)  6 (23.0)  6 (26.0)  0.63   COPD  6 (12.2)  3 (11.5)  3 (13.0)  0.71   CKD  15 (30.6)  8 (30.7)  7 (30.4)  0.82   CAD  9 (18.4)  5 (19.2)  4 (17.3)  0.90   PAOD  3 (6.1)  2 (7.7)  1 (4.3)  0.77   CVA  5 (10.2)  3 (11.5)  2 (8.6)  0.91   DM  5 (10.2)  3 (11.5)  2 (8.6)  0.86  Medication, n (%)   Antiplatelet  16 (32.7)  10 (38.4)  6 (26.0)  0.36   Anticoagulant  9 (18.4)  4 (15.3)  5 (21.7)  0.58   Statin  9 (18.4)  4 (15.3)  5 (21.7)  0.58  Indications for surgery, n (%)   Aneurysmal rupture  20 (40.8)  20 (76.9)  0     Malperfusion  4 (8.2)  4 (15.4)  0     Persistent back pain  1 (2)  1 (3.8)  0     Refractory hypertension  1 (2)  1 (3.8)  0     Large aneurysm (>6 cm)  20 (40.8)  0  20 (87)     Rapid growth  3 (6.1)  0  3 (13)      Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Total population   Age (years), mean ± SD  62.3 ± 11.1  61.0 ± 14.0  63.9 ± 7.9     Male, n (%)  40 (81.6)  20 (76.9)  20 (87.0)  0.37   Onset, mean ± SD    6.0 ± 4.3  597.9 ± 334.1    Comorbidities, n (%)   Hypertension  42 (85.7)  24 (92.3)  18 (78.2)  0.75   Smoking  12 (24.5)  6 (23.0)  6 (26.0)  0.63   COPD  6 (12.2)  3 (11.5)  3 (13.0)  0.71   CKD  15 (30.6)  8 (30.7)  7 (30.4)  0.82   CAD  9 (18.4)  5 (19.2)  4 (17.3)  0.90   PAOD  3 (6.1)  2 (7.7)  1 (4.3)  0.77   CVA  5 (10.2)  3 (11.5)  2 (8.6)  0.91   DM  5 (10.2)  3 (11.5)  2 (8.6)  0.86  Medication, n (%)   Antiplatelet  16 (32.7)  10 (38.4)  6 (26.0)  0.36   Anticoagulant  9 (18.4)  4 (15.3)  5 (21.7)  0.58   Statin  9 (18.4)  4 (15.3)  5 (21.7)  0.58  Indications for surgery, n (%)   Aneurysmal rupture  20 (40.8)  20 (76.9)  0     Malperfusion  4 (8.2)  4 (15.4)  0     Persistent back pain  1 (2)  1 (3.8)  0     Refractory hypertension  1 (2)  1 (3.8)  0     Large aneurysm (>6 cm)  20 (40.8)  0  20 (87)     Rapid growth  3 (6.1)  0  3 (13)    ACTBAD: acute complicated Type B aortic dissection; CAD: coronary artery disease; CCTBAD: chronic complicated Type B aortic dissection; CKD: chronic kidney disease, (Cr >2.0 mg/dl); COPD: chronic obstructive pulmonary disease; CVA: cerebral vascular accident; DM: diabetes mellitus; PAOD: peripheral artery occlusive disorder; SD: standard deviation; TEVAR: thoracic endovascular aortic repair. Table 1: Demographics and comorbidities in patients undergoing TEVAR for ACTBAD and CCTBAD   Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Total population   Age (years), mean ± SD  62.3 ± 11.1  61.0 ± 14.0  63.9 ± 7.9     Male, n (%)  40 (81.6)  20 (76.9)  20 (87.0)  0.37   Onset, mean ± SD    6.0 ± 4.3  597.9 ± 334.1    Comorbidities, n (%)   Hypertension  42 (85.7)  24 (92.3)  18 (78.2)  0.75   Smoking  12 (24.5)  6 (23.0)  6 (26.0)  0.63   COPD  6 (12.2)  3 (11.5)  3 (13.0)  0.71   CKD  15 (30.6)  8 (30.7)  7 (30.4)  0.82   CAD  9 (18.4)  5 (19.2)  4 (17.3)  0.90   PAOD  3 (6.1)  2 (7.7)  1 (4.3)  0.77   CVA  5 (10.2)  3 (11.5)  2 (8.6)  0.91   DM  5 (10.2)  3 (11.5)  2 (8.6)  0.86  Medication, n (%)   Antiplatelet  16 (32.7)  10 (38.4)  6 (26.0)  0.36   Anticoagulant  9 (18.4)  4 (15.3)  5 (21.7)  0.58   Statin  9 (18.4)  4 (15.3)  5 (21.7)  0.58  Indications for surgery, n (%)   Aneurysmal rupture  20 (40.8)  20 (76.9)  0     Malperfusion  4 (8.2)  4 (15.4)  0     Persistent back pain  1 (2)  1 (3.8)  0     Refractory hypertension  1 (2)  1 (3.8)  0     Large aneurysm (>6 cm)  20 (40.8)  0  20 (87)     Rapid growth  3 (6.1)  0  3 (13)      Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Total population   Age (years), mean ± SD  62.3 ± 11.1  61.0 ± 14.0  63.9 ± 7.9     Male, n (%)  40 (81.6)  20 (76.9)  20 (87.0)  0.37   Onset, mean ± SD    6.0 ± 4.3  597.9 ± 334.1    Comorbidities, n (%)   Hypertension  42 (85.7)  24 (92.3)  18 (78.2)  0.75   Smoking  12 (24.5)  6 (23.0)  6 (26.0)  0.63   COPD  6 (12.2)  3 (11.5)  3 (13.0)  0.71   CKD  15 (30.6)  8 (30.7)  7 (30.4)  0.82   CAD  9 (18.4)  5 (19.2)  4 (17.3)  0.90   PAOD  3 (6.1)  2 (7.7)  1 (4.3)  0.77   CVA  5 (10.2)  3 (11.5)  2 (8.6)  0.91   DM  5 (10.2)  3 (11.5)  2 (8.6)  0.86  Medication, n (%)   Antiplatelet  16 (32.7)  10 (38.4)  6 (26.0)  0.36   Anticoagulant  9 (18.4)  4 (15.3)  5 (21.7)  0.58   Statin  9 (18.4)  4 (15.3)  5 (21.7)  0.58  Indications for surgery, n (%)   Aneurysmal rupture  20 (40.8)  20 (76.9)  0     Malperfusion  4 (8.2)  4 (15.4)  0     Persistent back pain  1 (2)  1 (3.8)  0     Refractory hypertension  1 (2)  1 (3.8)  0     Large aneurysm (>6 cm)  20 (40.8)  0  20 (87)     Rapid growth  3 (6.1)  0  3 (13)    ACTBAD: acute complicated Type B aortic dissection; CAD: coronary artery disease; CCTBAD: chronic complicated Type B aortic dissection; CKD: chronic kidney disease, (Cr >2.0 mg/dl); COPD: chronic obstructive pulmonary disease; CVA: cerebral vascular accident; DM: diabetes mellitus; PAOD: peripheral artery occlusive disorder; SD: standard deviation; TEVAR: thoracic endovascular aortic repair. The patient’s mean age was 62.3 ± 11.1 years. Forty (81.6%) patients were male, and 42 (85.7%) patients had a history of hypertension. The interval of TEVAR for ACTBAD and CCTBAD were 6.0 ± 4.3 and 597.9 ± 334.1 days, respectively. The indications for TEVAR in 26 patients with ACTBAD were aneurysmal rupture in 20 (76.9%) patients, visceral or lower extremities malperfusion in 4 (15.4%) patients, persistent back pain in 1 (3.8%) patient and refractory hypertension in 1 (3.8%) patient. Of the 23 patients with CCTBAD, 21 (91.3%) patients had aneurysmal degeneration with an aortic diameter of more than 6 cm, and 2 (8.7%) patients had rapid aneurysmal growth (aneurysm expansion of aneurysm more than 0.5 cm within 0.5 year). All patients received TEVAR under general anaesthesia except 1 patient with a ruptured ACTBAD who received emergency TEVAR by percutaneous puncture under local anaesthesia. Spinal drainage was performed in 2 patients with ACTBAD and 1 patient with CCTBAD. The mean proximal endovascular graft diameter was similar in both the acute and chronic settings (38.2 ± 3.2 vs 36.7 ± 3.9 mm, P = 0.15). However, the distal endovascular graft diameter was significantly smaller in CCTBAD (35.7 ± 3.6 vs 33.5 ± 4.3 mm, P = 0.048). The percentage of tapered stent grafts did not differ between the 2 groups. The mean contrast usage, procedure and fluoroscopic time were the same in both groups. The planned site of the proximal endovascular graft necessitated additional procedures in 34 (69.4%) patients (ACTBAD: 14, CCTBAD: 20). LSCA revascularization was more frequently performed by a left carotid–subclavian bypass in CCTBAD and by chimney grafts in ACTBAD (34.7% vs 7.7%, P = 0.024). The LSCA was totally covered in 4 (8.2%) patients (ACTBAD: 2, CCTBAD: 2). The number of patients with proximal landing zones in Zone 0 were 2 in CCTBAD, 8 in Zone 1 (ACTBAD: 3, CCTBAD: 5), 28 in Zone 2 (ACTBAD: 15, CCTBAD: 13) and 11 in Zones 3 and 4 (ACTBAD: 8, CCTBAD: 3). Thirty-six (73.5%, ACTBAD: 21, CCTBAD: 15, P = 0.23) patients had aortic coverage above the T6 level and 13 (26.5%, ACTBAD: 5, CCTBAD: 8, P = 0.88) patients down to the coeliac level (Table 2). Additional procedure details are listed in Table 2. Table 2: Procedure data for ACTBAD and CCTBAD   Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Stent graft   Proximal (mm), mean ± SD  37.5 ± 3.53  38.2 ± 3.2  36.7 ± 3.9  0.15   Distal (mm), mean ± SD  34.67 ± 3.93  35.7 ± 3.6  33.5 ± 4.3  0.048   Tapered, n (%)  17 (34.7)  11 (42.3)  6 (26.1)  0.24  Associated procedures, n (%)   Left C-S bypass  10 (20.4)  2 (7.7)  8 (34.7)  0.024   VA transposition  1 (2)  0  1 (4.3)  0.33   C-C-S bypass  6 (12.2)  2 (7.7)  4 (17.7)  0.32   Left SCA chimney  13 (26.5)  10 (38.5)  3 (13.0)  0.041   Left CCA chimney  2 (4.1)  0  2 (8.7)  0.16   Supra-aortic debranching  1 (2)  0  1 (4.3)  0.33   Elephant trunk  1 (2)  0  1 (4.3)  0.33  Procedure details   General anaesthesia, n (%)  48 (98)  25 (96.1)  23 (100)  0.33   CSF drainage, n (%)  3 (6)  2 (7.7)  1 (4.3)  0.63   Left SCA coverage, n (%)  4 (8.1)  2 (7.7)  2 (8.7)  0.90   Percutaneous, n (%)  1 (2)  1 (3.8)  0  0.33   Operation time (min), mean ± SD  272.5 ± 155.6  260.2 ± 128.9  286.4 ± 185.8  0.55   Contrast medium (ml), mean ± SD  265.7 ± 174.83  276.9 ± 229.8  253.0 ± 112.7  0.61   Fluoroscopic time (min), mean ± SD  20.6 ± 14.3  22.1 ± 17.3  18.9 ± 10.9  0.39  Stent graft type, n (%)        0.64   TAG  22 (44.9)  10 (38.4)  12 (52.1)     Zenith  14 (28.6)  9 (34.6)  5 (21.7)     Talent  2 (4)  1 (3.8)  1 (4.3)     Valiant  10 (20.4)  6 (23.0)  4 (17.3)     Relay  1 (2)  0  1 (4.3)    Length of aortic coveragea, n (%)        0.22   Type A  36 (73.5)  21 (80.7)  15 (65.2)     Type B  13 (26.5)  5 (19.3)  8 (34.8)    Proximal landing zone, n (%)        0.31   0  2 (4)  0  2 (8.7)     1  8 (16.3)  3 (11.5)  5 (21.7)     2  28 (57.1)  15 (57.7)  13 (56.5)     3  7 (14.3)  5 (19.2)  2 (8.7)     4  4 (8.1)  3 (11.5)  1 (4.3)      Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Stent graft   Proximal (mm), mean ± SD  37.5 ± 3.53  38.2 ± 3.2  36.7 ± 3.9  0.15   Distal (mm), mean ± SD  34.67 ± 3.93  35.7 ± 3.6  33.5 ± 4.3  0.048   Tapered, n (%)  17 (34.7)  11 (42.3)  6 (26.1)  0.24  Associated procedures, n (%)   Left C-S bypass  10 (20.4)  2 (7.7)  8 (34.7)  0.024   VA transposition  1 (2)  0  1 (4.3)  0.33   C-C-S bypass  6 (12.2)  2 (7.7)  4 (17.7)  0.32   Left SCA chimney  13 (26.5)  10 (38.5)  3 (13.0)  0.041   Left CCA chimney  2 (4.1)  0  2 (8.7)  0.16   Supra-aortic debranching  1 (2)  0  1 (4.3)  0.33   Elephant trunk  1 (2)  0  1 (4.3)  0.33  Procedure details   General anaesthesia, n (%)  48 (98)  25 (96.1)  23 (100)  0.33   CSF drainage, n (%)  3 (6)  2 (7.7)  1 (4.3)  0.63   Left SCA coverage, n (%)  4 (8.1)  2 (7.7)  2 (8.7)  0.90   Percutaneous, n (%)  1 (2)  1 (3.8)  0  0.33   Operation time (min), mean ± SD  272.5 ± 155.6  260.2 ± 128.9  286.4 ± 185.8  0.55   Contrast medium (ml), mean ± SD  265.7 ± 174.83  276.9 ± 229.8  253.0 ± 112.7  0.61   Fluoroscopic time (min), mean ± SD  20.6 ± 14.3  22.1 ± 17.3  18.9 ± 10.9  0.39  Stent graft type, n (%)        0.64   TAG  22 (44.9)  10 (38.4)  12 (52.1)     Zenith  14 (28.6)  9 (34.6)  5 (21.7)     Talent  2 (4)  1 (3.8)  1 (4.3)     Valiant  10 (20.4)  6 (23.0)  4 (17.3)     Relay  1 (2)  0  1 (4.3)    Length of aortic coveragea, n (%)        0.22   Type A  36 (73.5)  21 (80.7)  15 (65.2)     Type B  13 (26.5)  5 (19.3)  8 (34.8)    Proximal landing zone, n (%)        0.31   0  2 (4)  0  2 (8.7)     1  8 (16.3)  3 (11.5)  5 (21.7)     2  28 (57.1)  15 (57.7)  13 (56.5)     3  7 (14.3)  5 (19.2)  2 (8.7)     4  4 (8.1)  3 (11.5)  1 (4.3)    a Length of aortic coverage: Type A: LSCA to T6, Type B: LSCA to coeliac axis. ACTBAD: acute complicated Type B aortic dissection; CCA: common carotid artery; CCTBAD: chronic complicated Type B aortic dissection; C-C-S: carotid-carotid-subclavian; C-S: carotid-subclavian; CSF: cerebrospinal fluid; LSCA: left subclavian artery; SCA: subclavian artery; SD: standard deviation; VA: vertebral artery. Table 2: Procedure data for ACTBAD and CCTBAD   Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Stent graft   Proximal (mm), mean ± SD  37.5 ± 3.53  38.2 ± 3.2  36.7 ± 3.9  0.15   Distal (mm), mean ± SD  34.67 ± 3.93  35.7 ± 3.6  33.5 ± 4.3  0.048   Tapered, n (%)  17 (34.7)  11 (42.3)  6 (26.1)  0.24  Associated procedures, n (%)   Left C-S bypass  10 (20.4)  2 (7.7)  8 (34.7)  0.024   VA transposition  1 (2)  0  1 (4.3)  0.33   C-C-S bypass  6 (12.2)  2 (7.7)  4 (17.7)  0.32   Left SCA chimney  13 (26.5)  10 (38.5)  3 (13.0)  0.041   Left CCA chimney  2 (4.1)  0  2 (8.7)  0.16   Supra-aortic debranching  1 (2)  0  1 (4.3)  0.33   Elephant trunk  1 (2)  0  1 (4.3)  0.33  Procedure details   General anaesthesia, n (%)  48 (98)  25 (96.1)  23 (100)  0.33   CSF drainage, n (%)  3 (6)  2 (7.7)  1 (4.3)  0.63   Left SCA coverage, n (%)  4 (8.1)  2 (7.7)  2 (8.7)  0.90   Percutaneous, n (%)  1 (2)  1 (3.8)  0  0.33   Operation time (min), mean ± SD  272.5 ± 155.6  260.2 ± 128.9  286.4 ± 185.8  0.55   Contrast medium (ml), mean ± SD  265.7 ± 174.83  276.9 ± 229.8  253.0 ± 112.7  0.61   Fluoroscopic time (min), mean ± SD  20.6 ± 14.3  22.1 ± 17.3  18.9 ± 10.9  0.39  Stent graft type, n (%)        0.64   TAG  22 (44.9)  10 (38.4)  12 (52.1)     Zenith  14 (28.6)  9 (34.6)  5 (21.7)     Talent  2 (4)  1 (3.8)  1 (4.3)     Valiant  10 (20.4)  6 (23.0)  4 (17.3)     Relay  1 (2)  0  1 (4.3)    Length of aortic coveragea, n (%)        0.22   Type A  36 (73.5)  21 (80.7)  15 (65.2)     Type B  13 (26.5)  5 (19.3)  8 (34.8)    Proximal landing zone, n (%)        0.31   0  2 (4)  0  2 (8.7)     1  8 (16.3)  3 (11.5)  5 (21.7)     2  28 (57.1)  15 (57.7)  13 (56.5)     3  7 (14.3)  5 (19.2)  2 (8.7)     4  4 (8.1)  3 (11.5)  1 (4.3)      Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Stent graft   Proximal (mm), mean ± SD  37.5 ± 3.53  38.2 ± 3.2  36.7 ± 3.9  0.15   Distal (mm), mean ± SD  34.67 ± 3.93  35.7 ± 3.6  33.5 ± 4.3  0.048   Tapered, n (%)  17 (34.7)  11 (42.3)  6 (26.1)  0.24  Associated procedures, n (%)   Left C-S bypass  10 (20.4)  2 (7.7)  8 (34.7)  0.024   VA transposition  1 (2)  0  1 (4.3)  0.33   C-C-S bypass  6 (12.2)  2 (7.7)  4 (17.7)  0.32   Left SCA chimney  13 (26.5)  10 (38.5)  3 (13.0)  0.041   Left CCA chimney  2 (4.1)  0  2 (8.7)  0.16   Supra-aortic debranching  1 (2)  0  1 (4.3)  0.33   Elephant trunk  1 (2)  0  1 (4.3)  0.33  Procedure details   General anaesthesia, n (%)  48 (98)  25 (96.1)  23 (100)  0.33   CSF drainage, n (%)  3 (6)  2 (7.7)  1 (4.3)  0.63   Left SCA coverage, n (%)  4 (8.1)  2 (7.7)  2 (8.7)  0.90   Percutaneous, n (%)  1 (2)  1 (3.8)  0  0.33   Operation time (min), mean ± SD  272.5 ± 155.6  260.2 ± 128.9  286.4 ± 185.8  0.55   Contrast medium (ml), mean ± SD  265.7 ± 174.83  276.9 ± 229.8  253.0 ± 112.7  0.61   Fluoroscopic time (min), mean ± SD  20.6 ± 14.3  22.1 ± 17.3  18.9 ± 10.9  0.39  Stent graft type, n (%)        0.64   TAG  22 (44.9)  10 (38.4)  12 (52.1)     Zenith  14 (28.6)  9 (34.6)  5 (21.7)     Talent  2 (4)  1 (3.8)  1 (4.3)     Valiant  10 (20.4)  6 (23.0)  4 (17.3)     Relay  1 (2)  0  1 (4.3)    Length of aortic coveragea, n (%)        0.22   Type A  36 (73.5)  21 (80.7)  15 (65.2)     Type B  13 (26.5)  5 (19.3)  8 (34.8)    Proximal landing zone, n (%)        0.31   0  2 (4)  0  2 (8.7)     1  8 (16.3)  3 (11.5)  5 (21.7)     2  28 (57.1)  15 (57.7)  13 (56.5)     3  7 (14.3)  5 (19.2)  2 (8.7)     4  4 (8.1)  3 (11.5)  1 (4.3)    a Length of aortic coverage: Type A: LSCA to T6, Type B: LSCA to coeliac axis. ACTBAD: acute complicated Type B aortic dissection; CCA: common carotid artery; CCTBAD: chronic complicated Type B aortic dissection; C-C-S: carotid-carotid-subclavian; C-S: carotid-subclavian; CSF: cerebrospinal fluid; LSCA: left subclavian artery; SCA: subclavian artery; SD: standard deviation; VA: vertebral artery. Thirty-day morbidity and mortality TEVAR was successful in all 49 patients. There were 2 deaths within 30 days in the acute group (7.7%) and none in the chronic group. In the acute group, 1 patient died of persistent bleeding even after a salvage TEVAR was performed for acute aortic rupture and the other from a delayed retrograde Type A dissection 1 week after the TEVAR procedure with a proximal bare metal stent graft. There was no stroke in either group. However, 2 patients developed paraplegia, 1 in each group. Temporary haemodialysis was required in 2 cases (4.0%). Other procedure-related complications included myocardial infarction (6.0%), pneumonia (4.0%) and vascular access bleeding (4.0%). There was no difference in 30-day mortality and complications between the acute and chronic groups (Table 3). Table 3: Surgical results and complications   Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Technical success, n (%)  49 (100)  26 (100)  23 (100)  0.99  30-Day mortality, n (%)  2 (4)  2 (7.7)  0  0.16  Procedure-related complication, n (%)   Paraplegia  2 (4)  1 (3.8)  1 (4.3)  0.93   CVA  0  0  0     MI  3 (6)  2 (7.7)  1 (4.3)  0.63   Pneumonia  2 (4)  1 (3.8)  1 (4.3)  0.93   Renal insufficiency  7 (14.3)  4 (15.4)  3 (13)  0.81    Without H/D  5  3  2      Temporary H/D  2  1  1      Long term H/D  0  0  0     Distal limb ischaemia  0  0  0  –   Vascular access bleeding  2 (4)  1 (3.8)  1 (4.3)  0.93  Device-related complications, n (%)   Proximal SINE  2 (4)  2 (7.7)  0  0.16    Immediate  1  1  0  0.33    Delayed  1  1  0  0.33   Distal SINE  1 (2)  1 (4.1)  0 (0)  0.33    Immediate  0  0  0      Delayed  1  1    0.33  Endoleak, n (%)        0.91   Type I  2 (4.0)  1 (3.8)  1 (4.3)     Type II (Non-LSCA)  3 (6)  2 (7.7)  1 (4.3)     Type II (LSCA)  2 (4)  1 (3.8)  1 (4.3)     Type III  0  0  0     Type IV  0  0  0    Extent of FL thrombosisa, n (%)        0.12   0  7 (14.9%)  1 (4.2%)  6 (26.0%)     I  11 (23.4%)  7 (29.1%)  4 (15.3%)     II  17 (36.1%)  8 (33.3%)  9 (39.1%)     III  12 (25.5%)  8 (33.3%)  4 (17.3%)      Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Technical success, n (%)  49 (100)  26 (100)  23 (100)  0.99  30-Day mortality, n (%)  2 (4)  2 (7.7)  0  0.16  Procedure-related complication, n (%)   Paraplegia  2 (4)  1 (3.8)  1 (4.3)  0.93   CVA  0  0  0     MI  3 (6)  2 (7.7)  1 (4.3)  0.63   Pneumonia  2 (4)  1 (3.8)  1 (4.3)  0.93   Renal insufficiency  7 (14.3)  4 (15.4)  3 (13)  0.81    Without H/D  5  3  2      Temporary H/D  2  1  1      Long term H/D  0  0  0     Distal limb ischaemia  0  0  0  –   Vascular access bleeding  2 (4)  1 (3.8)  1 (4.3)  0.93  Device-related complications, n (%)   Proximal SINE  2 (4)  2 (7.7)  0  0.16    Immediate  1  1  0  0.33    Delayed  1  1  0  0.33   Distal SINE  1 (2)  1 (4.1)  0 (0)  0.33    Immediate  0  0  0      Delayed  1  1    0.33  Endoleak, n (%)        0.91   Type I  2 (4.0)  1 (3.8)  1 (4.3)     Type II (Non-LSCA)  3 (6)  2 (7.7)  1 (4.3)     Type II (LSCA)  2 (4)  1 (3.8)  1 (4.3)     Type III  0  0  0     Type IV  0  0  0    Extent of FL thrombosisa, n (%)        0.12   0  7 (14.9%)  1 (4.2%)  6 (26.0%)     I  11 (23.4%)  7 (29.1%)  4 (15.3%)     II  17 (36.1%)  8 (33.3%)  9 (39.1%)     III  12 (25.5%)  8 (33.3%)  4 (17.3%)    a 0: some retrograde FL perfusion along stent graft; I: FL thrombosis along the stent graft; II: FL thrombosis to the coeliac artery; III: complete FL thrombosis. The false lumen thrombosis was analysed for 47 patients because 2 in-hospital death were excluded. ACTBAD: acute complicated Type B aortic dissection; CCTBAD: chronic complicated Type B aortic dissection; FL: false lumen; H/D: haemodialysis; LSCA: left subclavian artery; MI: myocardial infarction; SINE: stent graft-induced new entry. Table 3: Surgical results and complications   Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Technical success, n (%)  49 (100)  26 (100)  23 (100)  0.99  30-Day mortality, n (%)  2 (4)  2 (7.7)  0  0.16  Procedure-related complication, n (%)   Paraplegia  2 (4)  1 (3.8)  1 (4.3)  0.93   CVA  0  0  0     MI  3 (6)  2 (7.7)  1 (4.3)  0.63   Pneumonia  2 (4)  1 (3.8)  1 (4.3)  0.93   Renal insufficiency  7 (14.3)  4 (15.4)  3 (13)  0.81    Without H/D  5  3  2      Temporary H/D  2  1  1      Long term H/D  0  0  0     Distal limb ischaemia  0  0  0  –   Vascular access bleeding  2 (4)  1 (3.8)  1 (4.3)  0.93  Device-related complications, n (%)   Proximal SINE  2 (4)  2 (7.7)  0  0.16    Immediate  1  1  0  0.33    Delayed  1  1  0  0.33   Distal SINE  1 (2)  1 (4.1)  0 (0)  0.33    Immediate  0  0  0      Delayed  1  1    0.33  Endoleak, n (%)        0.91   Type I  2 (4.0)  1 (3.8)  1 (4.3)     Type II (Non-LSCA)  3 (6)  2 (7.7)  1 (4.3)     Type II (LSCA)  2 (4)  1 (3.8)  1 (4.3)     Type III  0  0  0     Type IV  0  0  0    Extent of FL thrombosisa, n (%)        0.12   0  7 (14.9%)  1 (4.2%)  6 (26.0%)     I  11 (23.4%)  7 (29.1%)  4 (15.3%)     II  17 (36.1%)  8 (33.3%)  9 (39.1%)     III  12 (25.5%)  8 (33.3%)  4 (17.3%)      Total (49)  ACTBAD (26)  CCTBAD (23)  P-value  Technical success, n (%)  49 (100)  26 (100)  23 (100)  0.99  30-Day mortality, n (%)  2 (4)  2 (7.7)  0  0.16  Procedure-related complication, n (%)   Paraplegia  2 (4)  1 (3.8)  1 (4.3)  0.93   CVA  0  0  0     MI  3 (6)  2 (7.7)  1 (4.3)  0.63   Pneumonia  2 (4)  1 (3.8)  1 (4.3)  0.93   Renal insufficiency  7 (14.3)  4 (15.4)  3 (13)  0.81    Without H/D  5  3  2      Temporary H/D  2  1  1      Long term H/D  0  0  0     Distal limb ischaemia  0  0  0  –   Vascular access bleeding  2 (4)  1 (3.8)  1 (4.3)  0.93  Device-related complications, n (%)   Proximal SINE  2 (4)  2 (7.7)  0  0.16    Immediate  1  1  0  0.33    Delayed  1  1  0  0.33   Distal SINE  1 (2)  1 (4.1)  0 (0)  0.33    Immediate  0  0  0      Delayed  1  1    0.33  Endoleak, n (%)        0.91   Type I  2 (4.0)  1 (3.8)  1 (4.3)     Type II (Non-LSCA)  3 (6)  2 (7.7)  1 (4.3)     Type II (LSCA)  2 (4)  1 (3.8)  1 (4.3)     Type III  0  0  0     Type IV  0  0  0    Extent of FL thrombosisa, n (%)        0.12   0  7 (14.9%)  1 (4.2%)  6 (26.0%)     I  11 (23.4%)  7 (29.1%)  4 (15.3%)     II  17 (36.1%)  8 (33.3%)  9 (39.1%)     III  12 (25.5%)  8 (33.3%)  4 (17.3%)    a 0: some retrograde FL perfusion along stent graft; I: FL thrombosis along the stent graft; II: FL thrombosis to the coeliac artery; III: complete FL thrombosis. The false lumen thrombosis was analysed for 47 patients because 2 in-hospital death were excluded. ACTBAD: acute complicated Type B aortic dissection; CCTBAD: chronic complicated Type B aortic dissection; FL: false lumen; H/D: haemodialysis; LSCA: left subclavian artery; MI: myocardial infarction; SINE: stent graft-induced new entry. Follow-up outcome The mean follow-up period was 27.5 ± 19.1 months in ACTBAD and 22.3 ± 10.9 months in CCTBAD, respectively. Six patients succumbed during the follow-up period (3 in each group). There was no difference in the cumulative freedom from all-cause mortality (ACTBAD: 77.6%, CCTBAD: 68.8%, P = 0.76) and aneurysmal-related mortality (ACTBAD: 88.2%, CCTBAD: 95.0%, P = 0.64) (Fig. 2A and B) between the 2 groups. One patient with ACTBAD died of an aorto-oesophageal fistula due to a late prosthetic infection 20 months after TEVAR. The other 2 died of terminal pancreatic cancer and a large cerebral infarction 22 and 28 months into the follow-up period, respectively. In the chronic group, 1 patient died of aortic rupture 1 month after discharge due to ongoing retrograde perfusion from the distal intimal tear in the non-stented aorta. The remaining 2 patients died of multiple organ failure after 32 and 36 months of follow-up. The cumulative freedom from reintervention rate of both groups were similar during the follow-up (ACTBAD: 92.3%, CCTBAD: 95.6%, P = 0.94) (Fig. 2C). Three patients required reintervention (ACTBAD: 2, CCTBAD: 1). In the acute setting, 1 patient required a secondary procedure for continued proximal aneurysmal enlargement due to a late Type I endovascular leak after 48 months of follow-up, and the other developed a distal stent graft-induced new entry (SINE) requiring an additional distal endograft extension 50 months after TEVAR. In the chronic cohort, 1 patient required a hybrid procedure with a retrograde visceral bypass and a thoracoabdominal stent graft due to persistent aneurysm formation in the abdominal aorta 21 months after TEVAR. During the follow-up, 5 patients who had persistent Type II endoleak required no intervention. No chimney graft (LSCA chimney: 13; LCCA chimney: 2) occlusion was detected. Figure 2: View largeDownload slide Actuarial (Kaplan–Meier) freedom from all-cause mortality (A), aneurysmal-related mortality (B) and reintervention (C). The numbers above the x-axis are the number of patients at risk. The P-value is calculated by the log-rank test. Figure 2: View largeDownload slide Actuarial (Kaplan–Meier) freedom from all-cause mortality (A), aneurysmal-related mortality (B) and reintervention (C). The numbers above the x-axis are the number of patients at risk. The P-value is calculated by the log-rank test. Aortic remodelling The extent of FL thrombosis after TEVAR was evaluated based on the latest CT scan of each patient, except for the 2 patients who died within 30 days after surgery in the acute group (Table 3). Overall, 12 (25.5%) patients experienced complete FL thrombosis along the whole aorta (ACTBAD: 8, CCTBAD: 4, P = 0.28). Seven (14.9%) patients continued to have some FL retrograde flow through a distal fenestration along the endovascular graft (ACTBAD: 1, CCTBAD: 6, P = 0.036). In summary, 35 (75.5%) patients still experienced FL flow in the abdominal aorta below the coeliac artery (ACTBAD: 16, CCTBAD: 19, P = 0.10). To check for any significant diameter changes of the TL and FL at the 6 aortic levels after endograft surgery, the cases were pooled and investigated together to determine the effects of acute versus chronic and the level of distal stent graft deployment on aortic remodelling. Significant increase in the TL diameter and decrease in the FL diameter at levels A, B and C (P < 0.001) were noted during the follow-up in both groups (Fig. 3). Following TEVAR, there was no significant difference in the TL expansion or the FL regression at 6 levels between the ACTBAD and CCTBAD groups (Fig. 4). When patients were stratified by the extent of the thoracic aortic coverage, no difference was found between ACTBAD and CCTBAD (Fig. 5). Figure 3: View largeDownload slide Periodic changes in true lumen and false lumen diameters for all complicated Type B aortic dissection at 6 aortic levels (A–F) recorded before (0), 1 month (1) and 1 year after TEVAR (2). The bars stand for mean ± standard error. The P-value indicates whether the time effect is significant for each lumen. TEVAR: thoracic endovascular aortic repair. Figure 3: View largeDownload slide Periodic changes in true lumen and false lumen diameters for all complicated Type B aortic dissection at 6 aortic levels (A–F) recorded before (0), 1 month (1) and 1 year after TEVAR (2). The bars stand for mean ± standard error. The P-value indicates whether the time effect is significant for each lumen. TEVAR: thoracic endovascular aortic repair. Figure 4: View largeDownload slide Periodic changes in true lumen (left panel) and false lumen (right panel) diameters at 6 aortic levels (A–F) between ACCTBAD and CCTBAD recorded before (0), 1 month (1) and 1 year after TEVAR (2). The bars stand for mean ± standard error. The P-value indicates whether the interaction effect between group (chronic and acute) and time is significant for each aortic level. ACTBAD: acute complicated Type B aortic dissection; CCTBAD: chronic complicated Type B aortic dissection; TEVAR: thoracic endovascular aortic repair. Figure 4: View largeDownload slide Periodic changes in true lumen (left panel) and false lumen (right panel) diameters at 6 aortic levels (A–F) between ACCTBAD and CCTBAD recorded before (0), 1 month (1) and 1 year after TEVAR (2). The bars stand for mean ± standard error. The P-value indicates whether the interaction effect between group (chronic and acute) and time is significant for each aortic level. ACTBAD: acute complicated Type B aortic dissection; CCTBAD: chronic complicated Type B aortic dissection; TEVAR: thoracic endovascular aortic repair. Figure 5: View largeDownload slide Periodic changes in true lumen (left panel) and false lumen (right panel) diameters at 6 aortic levels (A–F) between aortic coverage above and below T6 level recorded before (0), 1 month (1) and 1 year after TEVAR (2). The bars stand for mean ± standard error. The P-value indicates whether the interaction effect between group (above T6 and below T6) and time is significant for each aortic level. Figure 5: View largeDownload slide Periodic changes in true lumen (left panel) and false lumen (right panel) diameters at 6 aortic levels (A–F) between aortic coverage above and below T6 level recorded before (0), 1 month (1) and 1 year after TEVAR (2). The bars stand for mean ± standard error. The P-value indicates whether the interaction effect between group (above T6 and below T6) and time is significant for each aortic level. DISCUSSION Without early diagnosis and proper treatment, complicated TBAD is a cardiovascular event of high mortality [1, 20]. With the development and technical refinement of endovascular stent grafts, TEVAR has improved the outcome compared to the medical therapy and open surgical repair [9, 20]. Higher major complications and 30-day mortality have been reported in patients with ACTBAD undergoing TEVAR compared to patients with CCTBAD [21]. In our study, the 30-day mortality rates were 7.7% in patients with ACTBAD and 0% in those with CCTBAD, which was comparable with previous reports. However, no difference was found in major complication rates between ACTBAD and CCTBAD. Retrograde Type A dissection was a recognized complication of TEVAR and more frequently occurred in patients with acute disease. One of the deaths with ACTBAD in our study was attributed to the late onset of retrograde Type A dissection. However, the aetiology remained undefined and could have been related to the proximal bare metal stent, aggressive aortic ballooning or oversized stent graft [12]. The neurological complications, including stroke and paraplegia, were low in our study. This could be attributed to the high percentage of LSCA revascularization and short endograft aortic coverage. Ten patients in our study required more proximal landing (Zone 0: 2; Zone 1: 8) to achieve adequate exclusion. No stroke or retrograde Type A dissection occurred in any of these patients. Adjunctive procedures such as the chimney procedure or arch vessel debranching might not necessarily increase the complication rate for TBAD. At the 3-year follow-up, some studies showed a significantly poorer cumulative survival for patients with CCTBAD [22, 23]. However, no difference was found in all-cause mortality (P = 0.7612) and aneurysmal-related mortality (P = 0.64) between the ACTBAD and CCTBAD groups in our study. The reintervention rate during follow-up was also low for both groups (ACTBAD: 7.7%, CCTBAD: 4.3%). It was required in 1 case of proximal and 2 cases of distal aortic aneurysmal events. Oversizing of the stent graft has been reported to be the main risk for proximal or distal SINE [3]. Distal SINE might cause persistent FL perfusion and continuous aneurysmal expansion. In our protocol, we chose the stent graft with a diameter 10–15% larger than the diameter of the intended proximal landing area, and the stent was not intentionally tapered. The incidence of distal SINE in our study was 4.0%, which was similar to that reported in the literature and much lower than that with a stainless-steel-based stent graft [3, 13]. In this study, we did not appreciate the importance of downsizing the stent graft to prevent distal SINE [13]. This complication could be avoided by careful manipulation of the graft without excessive ballooning with current devices. The aim of TEVAR in aortic dissection was to cover the primary entry tear, stabilize the septum and re-establish perfusion to hypoperfused organs [21]. However, heterogeneous descriptions for aortic remodelling including the TL and FL diameters, areas and volumes after TEVAR have been measured. The maximum short axis diameter of both the TL and FL on axial CT images were measured in this study because the absolute diameter or diameter change was still the criterion for intervention in current practice. Aortic remodelling above the coeliac trunk artery was significant (P < 0.001). However, this was not the case below the coeliac trunk and reflected the concerns of TEVAR for TBAD. Coverage of a proximal primary tear alone did not promote distal aortic remodelling because the uncovered distal fenestration led to persistent flow and pressurization of the distal abdominal aorta. There was no significant difference between aortic remodelling in either ACTBAD or CCTBAD at any of the 6 levels. Despite the thickened intimal flap, thoracic aortic remodelling in CCTBAD was still favoured as an acute setting [14, 18]. In most studies, the FL thrombosis rate was similar in patients with ACTBAD and CCTBAD, ranging from 55% to 80%, and the FL thrombosis rate was usually greater at the level of the thoracic stent graft and lower below the diaphragm level [12, 15]. In our study, there were only 12 (25.5%) patients experiencing total FL thrombosis (ACTBAD: 8, CCTBAD: 4, P = 0.23), and 37 (75.5%) patients still experienced patent FL flow in the abdominal aorta. We did not observe any significant difference in FL thrombosis in the abdominal aorta between these 2 groups. However, the rate of persistent proximal FL perfusion along the thoracic stent graft was significantly higher in the CCTBAD group (P = 0.036). Despite the presence of FL flow, some investigators have suggested that TEVAR could still promote perigraft thrombosis. Only 1 patient with CCTBAD required reintervention in the distal abdominal aorta 21 months after TEVAR. However, longer follow-up for the detection of aneurysmal progression in the abdominal aortic segment is still warranted. The other unresolved issue related to TEVAR was the extent of endovascular graft coverage [2, 12]. Extensive coverage could decrease potential retrograde FL flow from downstream fenestration. However, the concern about extensive paving is justified due to the potential compromise of the critical blood supply to the spinal cord. In our study, we did not observe any significant difference in aortic remodelling when stratified by the extent of thoracic aortic coverage. Despite the relatively low rate of paraplegia in our study, we still preferred to cover only half of the length of the thoracic aorta to the extent necessary to relieve the malperfusion, restore the TL flow and prevent the spring-back effect [1]. Nevertheless, in patients presenting with aortic rupture, complete coverage of the entire thoracic aorta was usually required. Limitations The present investigation was conducted as a retrospective intention-to-treat analysis from a single centre. Half of our patients had not been followed up for more than 24 months, including the CT scan follow-up after 1 year. This follow-up period was relatively short for the evaluation of aneurysmal degeneration in the non-stented part of the abdominal aorta, and therefore it was not possible to fully examine the risk of reintervention. Further study with longer follow-up is required to define the association between TEVAR techniques and aortic remodelling, especially related to the abdominal aorta after TEVAR. CONCLUSIONS The early and 3-year follow-up in our study showed that endovascular repair for both ACTBAD and CCTBAD was safe and effective. Aortic remodelling was favourable above the coeliac artery after TEVAR, and no difference was found between ACTBAD and CCTBAD. The length of endograft coverage had no impact on the aortic remodelling. Low rate of FL thrombosis in the abdominal aorta warrants continuous imaging surveillance. Conflict of interest: none declared. REFERENCES 1 Fattori R, Cao P, De Rango P, Czerny M, Evangelista A, Nienaber C et al.   Interdisciplinary expert consensus document on management of type B aortic dissection. J Am Coll Cardiol  2013; 61: 1661– 78. Google Scholar CrossRef Search ADS PubMed  2 Lee M, Lee DY, Kim MD, Lee MS, Won JY, Park SI et al.   Outcomes of endovascular management for complicated chronic type B aortic dissection: effect of the extent of stent graft coverage and anatomic properties of aortic dissection. J Vasc Interv Radiol  2013; 24: 1451– 60. Google Scholar CrossRef Search ADS PubMed  3 Dong ZH, Fu WG, Wang YQ, Guo DQ, Xu X, Ji Y et al.   Retrograde type A aortic dissection after endovascular stent graft placement for treatment of type B dissection. Circulation  2009; 119: 735– 41. Google Scholar CrossRef Search ADS PubMed  4 Chemelli-Steingruber IE, Chemelli A, Strasak A, Hugl B, Hiemetzberger R, Czermak BV. Evaluation of volumetric measurements in patients with acute type B aortic dissection–thoracic endovascular aortic repair (TEVAR) vs conservative. J Vasc Surg  2009; 49: 20– 8. Google Scholar CrossRef Search ADS PubMed  5 Chemelli-Steingruber IE, Chemelli A, Strasak A, Hugl B, Hiemetzberger R, Jaschke W et al.   Endovascular repair or medical treatment of acute type B aortic dissection? A comparison. Eur J Radiol  2010; 73: 175– 80. Google Scholar CrossRef Search ADS PubMed  6 Tsai TT, Fattori R, Trimarchi S, Isselbacher E, Myrmel T, Evangelista A et al.   Long-term survival in patients presenting with type B acute aortic dissection: insights from the International Registry of Acute Aortic Dissection. Circulation  2006; 114: 2226– 31. Google Scholar CrossRef Search ADS PubMed  7 Garbade J, Jenniches M, Borger MA, Barten MJ, Scheinert D, Gutberlet M et al.   Outcome of patients suffering from acute type B aortic dissection: a retrospective single-centre analysis of 135 consecutive patients. Eur J Cardiothorac Surg  2010; 38: 285– 92. Google Scholar CrossRef Search ADS PubMed  8 Fattori R, Tsai TT, Myrmel T, Evangelista A, Cooper JV, Trimarchi S et al.   Complicated acute type B dissection: is surgery still the best option?: a report from the International Registry of Acute Aortic Dissection. JACC Cardiovasc Interv  2008; 1: 395– 402. Google Scholar CrossRef Search ADS PubMed  9 Estrera AL, Miller CC, Goodrick J, Porat EE, Achouh PE, Dhareshwar J et al.   Update on outcomes of acute type B aortic dissection. Ann Thorac Surg  2007; 83: S842– 50. Google Scholar CrossRef Search ADS PubMed  10 Erbel R, Alfonso F, Boileau C, Dirsch O, Eber B, Haverich A et al.   Providentia, diagnosis and management of aortic dissection. Eur Heart J  2001; 22: 1642– 81. Google Scholar CrossRef Search ADS PubMed  11 Swee W, Dake MD. Endovascular management of thoracic dissections. Circulation  2008; 117: 1460– 73. Google Scholar CrossRef Search ADS PubMed  12 Sayer D, Bratby M, Brooks M, Loftus I, Morgan R, Thompson M. Aortic morphology following endovascular repair of acute and chronic type B aortic dissection: implications for management. Eur J Vasc Endovasc Surg  2008; 36: 522– 9. Google Scholar CrossRef Search ADS PubMed  13 Yang CP, Hsu CP, Chen WY, Chen IM, Weng CF, Chen CK et al.   Aortic remodeling after endovascular repair with stainless steel-based stent graft in acute and chronic type B aortic dissection. J Vasc Surg  2012; 55: 1600– 10. Google Scholar CrossRef Search ADS PubMed  14 Sigman MM, Palmer OP, Ham SW, Cunningham M, Weaver FA. Aortic morphologic findings after thoracic endovascular aortic repair for type B aortic dissection. JAMA Surg  2014; 149: 977– 83. Google Scholar CrossRef Search ADS PubMed  15 Parsa CJ, Schroder JN, Daneshmand MA, McCann RL, Hughes GC. Midterm results for endovascular repair of complicated acute and chronic type B aortic dissection. Ann Thorac Surg  2010; 89: 97. Google Scholar CrossRef Search ADS PubMed  16 Criado FJ, Clark NS, Barnatan MF. Stent graft repair in the aortic arch and descending thoracic aorta: a 4-year experience. J Vasc Surg  2002; 36: 1121– 28. Google Scholar CrossRef Search ADS PubMed  17 Conrad MF, Crawford RS, Kwolek CJ, Brewster DC, Brady TJ, Cambria RP. Aortic remodeling after endovascular repair of acute complicated type B aortic dissection. J Vasc Surg  2009; 50: 510– 17. Google Scholar CrossRef Search ADS PubMed  18 Kusagawa H, Shimono T, Ishida M, Suzuki T, Yasuda F, Yuasa U et al.   Changes in false lumen after transluminal stent-graft placement in aortic dissections: six years’ experience. Circulation  2005; 111: 2951– 57. Google Scholar CrossRef Search ADS PubMed  19 Gorlitzer M, Weiss G, Meinhart J, Waldenberger F, Thalmann M, Folkmann S et al.   Fate of the false lumen after combined surgical and endovascular repair treating Stanford type A aortic dissections. Ann Thorac Surg  2010; 89: 794– 99. Google Scholar CrossRef Search ADS PubMed  20 Fattori R, Montgomery D, Lovato L, Kische S, Di Eusanio M, Ince H et al.   Survival after endovascular therapy in patients with type B aortic dissection: a report from the International Registry of Acute Aortic Dissection (IRAD). JACC Cardiovasc Interv  2013; 6: 876– 82. Google Scholar CrossRef Search ADS PubMed  21 Eggebrecht H, Nienaber CA, Neuhauser M, Baumgart D, Kische S, Schmermund A et al.   Endovascular stent-graft placement in aortic dissection: a meta-analysis. Eur Hear J  2006; 27: 489– 98. Google Scholar CrossRef Search ADS   22 Bozinovski J, Coselli JS. Outcomes and survival in surgical treatment of descending thoracic aorta with acute dissection. Ann Thorac Surg  2008; 85: 965– 5. Google Scholar CrossRef Search ADS PubMed  23 Zoli S, Etz CD, Roder F, Mueller CS, Brenner RM, Bodian CA et al.   Long-term survival after open repair of chronic distal aortic dissection. Ann Thorac Surg  2010; 89: 1458– 66. Google Scholar CrossRef Search ADS PubMed  © The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices)

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Interactive CardioVascular and Thoracic SurgeryOxford University Press

Published: May 22, 2018

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