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Simplified frozen elephant trunk technique for combined open and endovascular treatment of extensive aortic diseases

Simplified frozen elephant trunk technique for combined open and endovascular treatment of... Abstract View largeDownload slide View largeDownload slide OBJECTIVES This study aims to analyse the impact of a simplified frozen elephant trunk (FET) technique on early outcome. METHODS Between October 2010 and August 2018, 92 consecutive patients (mean age 64.4 ± 12.2 years) underwent FET surgery. Underlying pathologies were thoracic aneurysm in 35 patients, acute aortic dissection in 25 patients and chronic dissection in 32 patients. Thirty patients underwent a simplified FET technique with deployment of the stent graft in arch zone 2 with an extra-anatomic bypass to the distal left subclavian artery using the third branch of the Thoraflex™ Hybrid Plexus prosthesis via a supraclavicular access during reperfusion. These patients were compared to 62 patients who received the conventional FET procedure, in which a distal anastomosis is performed in arch zone 3. RESULTS Circulatory arrest (41.7 ± 10.5 vs 76.5 ± 33.0 min; P < 0.001) and antegrade cerebral perfusion times (60.9 ± 13.5 vs 92.1 ± 33.1 min; P < 0.001) were significantly reduced in zone 2 vs zone 3 patients, respectively. The 30-day mortality rate was 3.3% (n = 1) in zone 2 patients vs 17.7% (n = 11) in zone 3 patients (P = 0.75). Stent deployment in zone 2 was associated with significantly reduced rates of postoperative stroke [zone 2: n = 0 (0.0%); zone 3: n = 11 (17.7%), P = 0.046] and recurrent nerve palsy [zone 2: n = 1 (3.3%); zone 3: n = 14 (22.6%), P = 0.020). CONCLUSIONS Simplifying the FET procedure leads to reduced circulatory arrest and cerebral perfusion times and improves early outcome. Aortic aneurysm, Type A aortic dissection, Aortic arch replacement, Frozen elephant trunk, Subclavian artery, Endovascular procedures INTRODUCTION The frozen elephant trunk (FET) procedure is a treatment for patients with extensive thoracic aortic disease involving the arch and descending aorta. Owing to the complex surgical technique, early outcome remains unsatisfactory with mortality rates ranging from 6.4% to 15.8%, despite modern cerebral perfusion strategies [1]. Traditionally, the distal anastomosis in FET surgery is performed in the aortic arch zone 3. The main issues using this technique are the challenging distal aortic and supra-aortic vessel anastomoses. Tsagakis et al. [2] described a surgical strategy where the distal anastomosis is moved to zone 2 or further proximal, thus reducing the surgical trauma during FET procedures. However, this requires time-consuming rerouting strategies for the sacrificed left subclavian artery (LSA) by performing an aortic-subclavian or a carotid-subclavian bypass. In this study, we present a simplified surgical technique, in which the distal hybrid graft anastomosis in aortic arch zone 2 and a distal LSA anastomosis using the third branch of the Terumo Aortic Thoraflex™ Hybrid Plexus prosthesis (Terumo Aortic, Inchinnan, Scotland, UK) via an additional left supraclavicular access are performed. We compare procedural data and early outcome of this simplified technique with those of the traditional approach. MATERIALS AND METHODS Patients From October 2010 to August 2018, 92 consecutive patients underwent replacement of the thoracic aorta using the FET technique at our centre. In 30 of the 92 patients, the distal anastomosis was performed in aortic arch zone 2, whereas 62 patients received the conventional FET procedure performing the distal anastomosis in aortic arch zone 3. The mean age of all patients was 64.4 ± 12.2 years, with 58.7% of patients being men. Mean EuroSCORE II was 12.2 ± 12.4. Arterial hypertension was the most prevalent comorbidity in 89.1% of patients. Underlying pathologies were extensive aortic aneurysms with involvement of the entire thoracic or thoraco-abdominal aorta in 38.0% of patients, chronic type A or B dissections in 34.8% of patients and acute type A dissections in 27.2% of patients. Sixteen patients suffered from a connective tissue disorder. Twenty-three of the 92 patients underwent FET as a redo procedure and 6 patients sustained an acute aortic rupture and were treated in a bailout situation. The baseline characteristics of both study groups are shown in Table 1. Table 1: Patient characteristics Baseline characteristics Zone 2 (n = 30) Zone 3 (n = 62) P-value Age (years), mean ± SD 64.2 ± 13.2 64.5 ± 11.8 0.908 Male gender, n (%) 16 (53.3) 38 (61.3) 0.467 Arterial hypertension, n (%) 27 (90.0) 55 (88.7) 1.000 Genetic aortic syndrome, n (%) 6 (20.0) 10 (16.1) 0.646 EuroSCORE II, mean ± SD 7.6 ± 3.4 14.4 ± 14.4 <0.001 Pathologies, n (%)  Extensive thoracic aneurysm 15 (50.0) 20 (32.3) 0.100  Acute type A dissection 2 (6.7) 23 (37.1) 0.002  Chronic type A/B dissection 13 (43.3) 19 (30.6) 0.231 Acute aortic rupture, n (%) 0 (0.0) 6 (9.7) 0.172 Emergency procedures (<24 h), n (%) 2 (6.7) 21 (33.9) 0.005 Redo surgery, n (%) 10 (33.3) 13 (21.0) 0.199 Baseline characteristics Zone 2 (n = 30) Zone 3 (n = 62) P-value Age (years), mean ± SD 64.2 ± 13.2 64.5 ± 11.8 0.908 Male gender, n (%) 16 (53.3) 38 (61.3) 0.467 Arterial hypertension, n (%) 27 (90.0) 55 (88.7) 1.000 Genetic aortic syndrome, n (%) 6 (20.0) 10 (16.1) 0.646 EuroSCORE II, mean ± SD 7.6 ± 3.4 14.4 ± 14.4 <0.001 Pathologies, n (%)  Extensive thoracic aneurysm 15 (50.0) 20 (32.3) 0.100  Acute type A dissection 2 (6.7) 23 (37.1) 0.002  Chronic type A/B dissection 13 (43.3) 19 (30.6) 0.231 Acute aortic rupture, n (%) 0 (0.0) 6 (9.7) 0.172 Emergency procedures (<24 h), n (%) 2 (6.7) 21 (33.9) 0.005 Redo surgery, n (%) 10 (33.3) 13 (21.0) 0.199 SD: standard deviation. Statistically significant values are in bold (P < 0.05). Table 1: Patient characteristics Baseline characteristics Zone 2 (n = 30) Zone 3 (n = 62) P-value Age (years), mean ± SD 64.2 ± 13.2 64.5 ± 11.8 0.908 Male gender, n (%) 16 (53.3) 38 (61.3) 0.467 Arterial hypertension, n (%) 27 (90.0) 55 (88.7) 1.000 Genetic aortic syndrome, n (%) 6 (20.0) 10 (16.1) 0.646 EuroSCORE II, mean ± SD 7.6 ± 3.4 14.4 ± 14.4 <0.001 Pathologies, n (%)  Extensive thoracic aneurysm 15 (50.0) 20 (32.3) 0.100  Acute type A dissection 2 (6.7) 23 (37.1) 0.002  Chronic type A/B dissection 13 (43.3) 19 (30.6) 0.231 Acute aortic rupture, n (%) 0 (0.0) 6 (9.7) 0.172 Emergency procedures (<24 h), n (%) 2 (6.7) 21 (33.9) 0.005 Redo surgery, n (%) 10 (33.3) 13 (21.0) 0.199 Baseline characteristics Zone 2 (n = 30) Zone 3 (n = 62) P-value Age (years), mean ± SD 64.2 ± 13.2 64.5 ± 11.8 0.908 Male gender, n (%) 16 (53.3) 38 (61.3) 0.467 Arterial hypertension, n (%) 27 (90.0) 55 (88.7) 1.000 Genetic aortic syndrome, n (%) 6 (20.0) 10 (16.1) 0.646 EuroSCORE II, mean ± SD 7.6 ± 3.4 14.4 ± 14.4 <0.001 Pathologies, n (%)  Extensive thoracic aneurysm 15 (50.0) 20 (32.3) 0.100  Acute type A dissection 2 (6.7) 23 (37.1) 0.002  Chronic type A/B dissection 13 (43.3) 19 (30.6) 0.231 Acute aortic rupture, n (%) 0 (0.0) 6 (9.7) 0.172 Emergency procedures (<24 h), n (%) 2 (6.7) 21 (33.9) 0.005 Redo surgery, n (%) 10 (33.3) 13 (21.0) 0.199 SD: standard deviation. Statistically significant values are in bold (P < 0.05). Patient data were prospectively collected using our dedicated institutional aortic database. Clinical and follow-up characteristics were retrospectively analysed. Surgical techniques All operations were performed via a median sternotomy. Conventional frozen elephant trunk technique: distal anastomosis in aortic arch zone 3 Sixty-two patients of the 92 patients received the conventional FET procedure, in which the distal anastomosis is performed in aortic arch zone 3. For cardiopulmonary bypass (CPB), cannulation of the subclavian artery (n = 13), innominate artery (n = 20), femoral artery (n = 1) or direct cannulation of the ascending aorta/arch using the Seldinger’s technique (n = 28) was performed. Venous drainage was obtained by cannulation of the right atrium. In redo operations, the right femoral vein was cannulated percutaneously using the Seldinger’s technique and advanced towards the superior vena cava under transoesophageal echocardiography guidance. The left ventricle was vented via the right superior pulmonary vein. Antegrade and retrograde blood cardioplegia was used in all patients for myocardial protection. Cerebral protection was performed in all patients using moderate hypothermic circulatory arrest (HCA) between 24 and 26°C and bilateral selective antegrade cerebral perfusion (SACP). Arterial blood pressure was measured in the right radial and femoral artery. Near infrared spectroscopy was used to monitor cerebral perfusion by measuring oxygen saturation. Continuous carbon dioxide insufflation was used in all patients. In right subclavian or innominate artery cannulation, the brachiocephalic trunk was proximally clamped and right-sided unilateral SACP was started after the intended temperature had been reached. The ascending aorta and proximal aortic arch were transected, and a cerebral perfusion catheter was inserted into the left common carotid artery to provide bilateral SACP. In case of direct cannulation of the ascending aorta/arch, 2 catheters were inserted into the innominate and left carotid artery for bilateral SACP. The perfusion catheters were secured using tourniquets to prevent migration and embolization of tissue debris. The cerebral flow rate was set to 10–15 ml/kg/min with a mean pressure of 50–70 mmHg. The aortic arch was resected distally from the LSA origin. A strong aortic stump of the proximal descending aorta was created to facilitate the distal anastomosis. In acute and chronic dissection, the false lumen was occluded using interrupted U-stitches with pledgets to avoid a purse-string effect. The compacted stent section of the prosthesis was smoothly inserted into the descending aorta after proper bending of the distal stent part to fit distal aortic anatomy, thereby avoiding distal aortic perforation or mobilization of any thrombus that may have formed. In chronic dissections or patients with a kinked or tortuous aorta, a guidewire was inserted into the true lumen guided by echocardiography. The delivery system was removed and the self-expanding FET stent deployed. In all cases, the distal graft anastomosis with the proximal descending aortic stump was performed using a 3–0 polypropylene running suture. A large piece of Teflon felt was used on the outside of the aorta. BioGlue (CryoLife Inc., Kennesaw, GA, USA) was applied after performing the distal anastomosis during circulatory arrest. In 11 patients, the Jotec E-vita open plus hybrid prosthesis (Jotec, Hechingen, Germany) and in 51 patients, the Terumo Aortic Thoraflex Hybrid Plexus prosthesis was used. The supra-aortic vessels were reimplanted on the aortic arch graft using the classical island technique in all 11 patients with the E-vita open prosthesis and in the initial 8 patients who had the Thoraflex Hybrid prosthesis implanted. The reason for using the island technique was due to the fact that all implanting surgeons were accustomed and trained to perform this technique. In the following 43 patients, we changed to the branched technique. In these cases, all 3 head vessels were transected and replaced using the 3 branches of the Thoraflex Hybrid prosthesis (branched technique). Finally, total aortic arch and ascending replacement was completed by the proximal anastomosis to the ascending aortic stump or an aortic root graft, depending on the proximal aortic procedure. Additional proximal aortic and concomitant procedures are summarized in Table 2. Subsequently, the heart was deaired and the aortic clamp removed. Table 2: Surgical technique and additional procedures Arch zone 2 (n = 30), n (%) Arch zone 3 (n = 62), n (%) P-value FET hybrid prosthesis 0.014  Jotec E-vita open plus hybrid 0 (0.0) 11 (17.7)  Thoraflex™ Hybrid Plexus 30 (100.0) 51 (82.3) Supra-aortic vessels 0.001  Island technique 0 (0.0) 19 (30.6)  Branched technique 30 (100.0) 43 (69.4) Ascending procedures  Supracoronary replacement 24 (80.0) 42 (67.7) 0.221  Bentall procedure 4 (13.3) 13 (21.0) 0.376  David procedure 2 (6.7) 6 (9.7) 1.000 Additional CABG 2 (6.7) 5 (8.1) 1.000 Additional TVR 0 (0.0) 1 (1.6) 1.000 Arch zone 2 (n = 30), n (%) Arch zone 3 (n = 62), n (%) P-value FET hybrid prosthesis 0.014  Jotec E-vita open plus hybrid 0 (0.0) 11 (17.7)  Thoraflex™ Hybrid Plexus 30 (100.0) 51 (82.3) Supra-aortic vessels 0.001  Island technique 0 (0.0) 19 (30.6)  Branched technique 30 (100.0) 43 (69.4) Ascending procedures  Supracoronary replacement 24 (80.0) 42 (67.7) 0.221  Bentall procedure 4 (13.3) 13 (21.0) 0.376  David procedure 2 (6.7) 6 (9.7) 1.000 Additional CABG 2 (6.7) 5 (8.1) 1.000 Additional TVR 0 (0.0) 1 (1.6) 1.000 CABG: coronary artery bypass grafting; FET: frozen elephant trunk; TVR: tricuspid valve repair. Statistically significant values are in bold (P < 0.05). Table 2: Surgical technique and additional procedures Arch zone 2 (n = 30), n (%) Arch zone 3 (n = 62), n (%) P-value FET hybrid prosthesis 0.014  Jotec E-vita open plus hybrid 0 (0.0) 11 (17.7)  Thoraflex™ Hybrid Plexus 30 (100.0) 51 (82.3) Supra-aortic vessels 0.001  Island technique 0 (0.0) 19 (30.6)  Branched technique 30 (100.0) 43 (69.4) Ascending procedures  Supracoronary replacement 24 (80.0) 42 (67.7) 0.221  Bentall procedure 4 (13.3) 13 (21.0) 0.376  David procedure 2 (6.7) 6 (9.7) 1.000 Additional CABG 2 (6.7) 5 (8.1) 1.000 Additional TVR 0 (0.0) 1 (1.6) 1.000 Arch zone 2 (n = 30), n (%) Arch zone 3 (n = 62), n (%) P-value FET hybrid prosthesis 0.014  Jotec E-vita open plus hybrid 0 (0.0) 11 (17.7)  Thoraflex™ Hybrid Plexus 30 (100.0) 51 (82.3) Supra-aortic vessels 0.001  Island technique 0 (0.0) 19 (30.6)  Branched technique 30 (100.0) 43 (69.4) Ascending procedures  Supracoronary replacement 24 (80.0) 42 (67.7) 0.221  Bentall procedure 4 (13.3) 13 (21.0) 0.376  David procedure 2 (6.7) 6 (9.7) 1.000 Additional CABG 2 (6.7) 5 (8.1) 1.000 Additional TVR 0 (0.0) 1 (1.6) 1.000 CABG: coronary artery bypass grafting; FET: frozen elephant trunk; TVR: tricuspid valve repair. Statistically significant values are in bold (P < 0.05). Simplified frozen elephant trunk technique: distal anastomosis in aortic arch zone 2 Using the simplified FET technique, the LSA was exposed via a left-sided supraclavicular approach (Fig. 1A). An 8-mm Dacron graft (Gelweave™ prosthesis, Terumo Aortic) was sutured to the anterior side of the LSA in a T-graft fashion (LSA T-graft) with slight downwards angulation of the prosthesis to avoid kinking of the graft (Fig. 2A). The graft was cannulated using a 22-Fr arterial inflow cannula for full body perfusion and blood supply to the left arm (Fig. 1B). Venous drainage was obtained by cannulation of the right atrium. Figure 1: View largeDownload slide The simplified frozen elephant trunk technique (schematic illustration). (A) Exposure of the LSA via a left-sided supraclavicular approach. (B) An 8-mm Dacron graft is sutured to the LSA (LSA T-graft) and cannulated using a 22-Fr arterial cannula. (C) The first and second branches of the TH prosthesis are anastomosed to the innominate and left common carotid artery. (D) During reperfusion, the Dacron prosthesis to the LSA is shortened and anastomosed to the third branch of the TH prosthesis in an end-to-end fashion. ECC: extracorporeal circulation; LSA: left subclavian artery; TH: Thoraflex™ Hybrid. Figure 1: View largeDownload slide The simplified frozen elephant trunk technique (schematic illustration). (A) Exposure of the LSA via a left-sided supraclavicular approach. (B) An 8-mm Dacron graft is sutured to the LSA (LSA T-graft) and cannulated using a 22-Fr arterial cannula. (C) The first and second branches of the TH prosthesis are anastomosed to the innominate and left common carotid artery. (D) During reperfusion, the Dacron prosthesis to the LSA is shortened and anastomosed to the third branch of the TH prosthesis in an end-to-end fashion. ECC: extracorporeal circulation; LSA: left subclavian artery; TH: Thoraflex™ Hybrid. Figure 2: View largeDownload slide Intraoperative images. (A) Anastomosis of an 8-mm Dacron prosthesis with the LSA (LSA T-graft). (B) LSA T-graft (cannulated with a 22-Fr. arterial cannula) and third branch of the Thoraflex™ Hybrid prosthesis. (C) The third branch is pulled below the clavicle and anastomosed with the LSA T-graft. (D) Thoraflex Hybrid prosthesis in situ after finishing all anastomoses. LSA: left subclavian artery. Figure 2: View largeDownload slide Intraoperative images. (A) Anastomosis of an 8-mm Dacron prosthesis with the LSA (LSA T-graft). (B) LSA T-graft (cannulated with a 22-Fr. arterial cannula) and third branch of the Thoraflex™ Hybrid prosthesis. (C) The third branch is pulled below the clavicle and anastomosed with the LSA T-graft. (D) Thoraflex Hybrid prosthesis in situ after finishing all anastomoses. LSA: left subclavian artery. During moderate HCA and SACP, the aortic arch was transected between the left common carotid artery and the LSA. The origin of the LSA was ligated twice using 2/0 ethibond sutures. The compacted stent section of the Thoraflex Hybrid prosthesis was inserted into the distal arch and deployed in the descending aorta with overstenting the origin of the LSA. The distal graft anastomosis was performed in zone 2 using the sewing collar of the Thoraflex Hybrid prosthesis. After completion of the distal anastomosis, the perfusion side branch of the prosthesis was cannulated and CPB restarted to provide early antegrade lower body perfusion. Subsequently, the Thoraflex Hybrid prosthesis and the 3 side branches were deaired, clamped and the distal anastomosis was checked for bleeding under full pressure. Thereafter, the second and first branches of the prosthesis were anastomosed to the left common carotid and innominate artery using 5.0 and 4.0 Prolene running sutures, respectively, while slow rewarming of the patient was initiated. The proximal end of the hybrid graft was finally anastomosed either to the ascending aorta or an aortic root graft, if indicated (Fig. 1C). After deairing, the aortic clamp was removed and myocardial perfusion started. During reperfusion and rewarming on the beating heart, a retroclavicular tunnel between the left supraclavicular incision and the upper thoracic aperture was created by blunt dissection. The third side branch of the prosthesis was pulled upwards below the left sternoclavicular joint to the left supraclavicular incision. To complete the procedure, the LSA T-graft previously used for arterial inflow, was shortened and anastomosed to the third branch of the Thoraflex Hybrid prosthesis in an end-to-end fashion (Figs 1D and 2C). A postoperative computed tomography (CT) scan is shown in Fig. 3. Figure 3: View largeDownload slide Postoperative computed tomography scan. (A) Ventral view. Heart and supra-aortic head vessels after frozen elephant trunk surgery. (B) Zoomed ventral view. The IA and the LCA were transected and replaced using the first and second branches of the Thoraflex™ Hybrid prosthesis. The third branch of the prosthesis was anastomosed in an end-to-end fashion to the Dacron graft, which was sutured to the LSA as T-graft. (C) Zoomed left cranial view for better visualization of the supra-aortic vessels and ligated LSA’s origin. IA: innominate artery; LCA: left common carotid artery; LSA: left subclavian artery. Figure 3: View largeDownload slide Postoperative computed tomography scan. (A) Ventral view. Heart and supra-aortic head vessels after frozen elephant trunk surgery. (B) Zoomed ventral view. The IA and the LCA were transected and replaced using the first and second branches of the Thoraflex™ Hybrid prosthesis. The third branch of the prosthesis was anastomosed in an end-to-end fashion to the Dacron graft, which was sutured to the LSA as T-graft. (C) Zoomed left cranial view for better visualization of the supra-aortic vessels and ligated LSA’s origin. IA: innominate artery; LCA: left common carotid artery; LSA: left subclavian artery. Stent graft sizing and length Stent graft sizing of the hybrid prosthesis was made according to the preoperative CT scan with 10% oversizing in thoracic aneurysms based on the diameter of the descending aorta to prevent the occurrence of type Ib endoleaks. In acute aortic dissections and patients with connective tissue disorders, we measured the total diameter of the aorta and no oversizing was performed. In chronic dissections, the stent graft sizing was performed according to the dimensions of the true lumen measured in the CT scan and by intraoperative sizing. In the first 11 patients, the E-vita open prosthesis with a stent length of 150 mm was used. Since April 2013, the Thoraflex Hybrid prostheses were implanted. Initially, we used the 100 mm stent length in most of the patients to avoid a distal landing zone lower than T10. In zone 2 placement, however, we used the 150 mm stent length due to the fact that the placement of the stent graft is at least 3–5 cm higher. Statistical analysis Baseline categorical variables were summarized by frequencies and percentages. These were compared between study groups using the Fisher’s exact test. Continuous variables were described by mean ± standard deviation and compared between study groups using the 2-sided Student’s t-test. As this is a non-randomized study, baseline differences between groups in relevant prognostic factors can occur, which can bias the observed intervention effect. Therefore, we reported treatment effects adjusted for factors, which differ between groups according to Hickey et al. [3]. Continuous outcomes, e.g. intraoperative data on timings, were analysed in a multivariable linear model and adjusted differences and confidence intervals (CIs) were reported. Binary outcomes, e.g. 30-day mortality and postoperative complications were analysed using multivariable logistic regression models applying Firth’s correction to the likelihood to account for the small sample size and the limited number of events. Adjusted odds ratios (ORs), 95% CIs and P-values were reported from these models. The level of significance for all analyses was set at alpha = 0.05. Because this was an exploratory study, no adjustment for multiple testing was performed [4]. Statistical analyses were performed using IBM SPSS Version 24.0.0.0 and the logistf-package in R 3-4.4. RESULTS In 30 of the 92 FET cases, the distal anastomosis of the stent graft was performed in the aortic arch zone 2. Zone 2 cases differ from zone 3 cases at baseline in terms of EuroSCORE II and the incidence of acute type A dissections. Therefore, these factors were used as confounders. In zone 2 cases, the circulatory arrest time (adjusted delta = −27.8 min, 95% CI −40.1 to −15.4; P < 0.001) and the cerebral perfusion time (adjusted delta = −27.5 min, 95% CI −40.8 to −14.2; P < 0.001) were significantly reduced when compared to cases with stent deployment in aortic arch zone 3 (Table 3). The stent deployment in zone 2 was associated with significantly reduced rates of postoperative stroke [zone 2: n = 0 (0.0%); zone 3 n = 11 (17.7%), adjusted OR = 0.11, 95% CI 0.00–0.97; P = 0.046] and recurrent nerve palsy [zone 2: n = 2 (3.3%); zone 3: n = 14 (22.6%), adjusted OR = 0.17, 95% CI 0.02–0.78; P = 0.020]. Overall, 30-day mortality including other perioperative complications, such as paraplegia, transient ischaemic attack, renal failure and resternotomy for bleeding or tamponade were less frequent in patients with stent deployment in zone 2 as compared to zone 3 patients. However, this data did not reach statistical significance (Table 4). Table 3: Intraoperative data Arch zone 2 (n = 30), mean ± SD Arch zone 3 (n = 62), mean ± SD Difference (95% CI) P-value Extracorporeal circulation time (min) 231.7 ± 59.0 285.2 ± 82.5 −26.2 (−58.5 to 6.0) 0.11 Aortic clamp time (min) 114.4 ± 38.6 152.9 ± 60.4 −20.5 (−43.8 to 2.8) 0.083 Circulatory arrest time (min) 41.7 ± 10.5 76.5 ± 33.0 −27.8 (−40.1 to −15.4) <0.001 Cerebral perfusion time (min) 60.9 ± 13.5 92.1 ± 33.1 −27.5 (−40.8 to −14.2) <0.001 Deepest body temperature (°C) 23.9 ± 1.2 23.8 ± 1.9 −0.2 (−1.0 to 0.7) 0.71 Arch zone 2 (n = 30), mean ± SD Arch zone 3 (n = 62), mean ± SD Difference (95% CI) P-value Extracorporeal circulation time (min) 231.7 ± 59.0 285.2 ± 82.5 −26.2 (−58.5 to 6.0) 0.11 Aortic clamp time (min) 114.4 ± 38.6 152.9 ± 60.4 −20.5 (−43.8 to 2.8) 0.083 Circulatory arrest time (min) 41.7 ± 10.5 76.5 ± 33.0 −27.8 (−40.1 to −15.4) <0.001 Cerebral perfusion time (min) 60.9 ± 13.5 92.1 ± 33.1 −27.5 (−40.8 to −14.2) <0.001 Deepest body temperature (°C) 23.9 ± 1.2 23.8 ± 1.9 −0.2 (−1.0 to 0.7) 0.71 SD is reported as the measure of variability. Statistically significant values are in bold (P < 0.05). CI: confidence interval; SD: standard deviation. Table 3: Intraoperative data Arch zone 2 (n = 30), mean ± SD Arch zone 3 (n = 62), mean ± SD Difference (95% CI) P-value Extracorporeal circulation time (min) 231.7 ± 59.0 285.2 ± 82.5 −26.2 (−58.5 to 6.0) 0.11 Aortic clamp time (min) 114.4 ± 38.6 152.9 ± 60.4 −20.5 (−43.8 to 2.8) 0.083 Circulatory arrest time (min) 41.7 ± 10.5 76.5 ± 33.0 −27.8 (−40.1 to −15.4) <0.001 Cerebral perfusion time (min) 60.9 ± 13.5 92.1 ± 33.1 −27.5 (−40.8 to −14.2) <0.001 Deepest body temperature (°C) 23.9 ± 1.2 23.8 ± 1.9 −0.2 (−1.0 to 0.7) 0.71 Arch zone 2 (n = 30), mean ± SD Arch zone 3 (n = 62), mean ± SD Difference (95% CI) P-value Extracorporeal circulation time (min) 231.7 ± 59.0 285.2 ± 82.5 −26.2 (−58.5 to 6.0) 0.11 Aortic clamp time (min) 114.4 ± 38.6 152.9 ± 60.4 −20.5 (−43.8 to 2.8) 0.083 Circulatory arrest time (min) 41.7 ± 10.5 76.5 ± 33.0 −27.8 (−40.1 to −15.4) <0.001 Cerebral perfusion time (min) 60.9 ± 13.5 92.1 ± 33.1 −27.5 (−40.8 to −14.2) <0.001 Deepest body temperature (°C) 23.9 ± 1.2 23.8 ± 1.9 −0.2 (−1.0 to 0.7) 0.71 SD is reported as the measure of variability. Statistically significant values are in bold (P < 0.05). CI: confidence interval; SD: standard deviation. Table 4: Early mortality and postoperative complications Arch zone 2 (n = 30), n (%) Arch zone 3 (n = 62), n (%) OR (95% CI) P-value Overall 30-day mortality 1 (3.3) 11 (17.7) 0.73 (0.07–4.94) 0.75 Paraplegia 0 (0.0) 1 (1.6) Stroke 0 (0.0) 11 (17.7) 0.11 (0.00–0.97) 0.046 Transient ischaemic attack 0 (0.0) 9 (14.5) 0.12 (0.00–1.12) 0.065 Recurrent nerve palsy 1 (3.3) 14 (22.6) 0.17 (0.02–0.78) 0.020 Renal failure/dialysis 4 (13.3) 11 (17.7) 1.21 (0.30–4.53) 0.78 Resternotomy for bleeding/tamponade 1 (3.3) 11 (17.7) 0.25 (0.03–1.24) 0.094 Arch zone 2 (n = 30), n (%) Arch zone 3 (n = 62), n (%) OR (95% CI) P-value Overall 30-day mortality 1 (3.3) 11 (17.7) 0.73 (0.07–4.94) 0.75 Paraplegia 0 (0.0) 1 (1.6) Stroke 0 (0.0) 11 (17.7) 0.11 (0.00–0.97) 0.046 Transient ischaemic attack 0 (0.0) 9 (14.5) 0.12 (0.00–1.12) 0.065 Recurrent nerve palsy 1 (3.3) 14 (22.6) 0.17 (0.02–0.78) 0.020 Renal failure/dialysis 4 (13.3) 11 (17.7) 1.21 (0.30–4.53) 0.78 Resternotomy for bleeding/tamponade 1 (3.3) 11 (17.7) 0.25 (0.03–1.24) 0.094 CI: confidence interval; OR: odds ratio. Statistically significant values are in bold (P < 0.05). Table 4: Early mortality and postoperative complications Arch zone 2 (n = 30), n (%) Arch zone 3 (n = 62), n (%) OR (95% CI) P-value Overall 30-day mortality 1 (3.3) 11 (17.7) 0.73 (0.07–4.94) 0.75 Paraplegia 0 (0.0) 1 (1.6) Stroke 0 (0.0) 11 (17.7) 0.11 (0.00–0.97) 0.046 Transient ischaemic attack 0 (0.0) 9 (14.5) 0.12 (0.00–1.12) 0.065 Recurrent nerve palsy 1 (3.3) 14 (22.6) 0.17 (0.02–0.78) 0.020 Renal failure/dialysis 4 (13.3) 11 (17.7) 1.21 (0.30–4.53) 0.78 Resternotomy for bleeding/tamponade 1 (3.3) 11 (17.7) 0.25 (0.03–1.24) 0.094 Arch zone 2 (n = 30), n (%) Arch zone 3 (n = 62), n (%) OR (95% CI) P-value Overall 30-day mortality 1 (3.3) 11 (17.7) 0.73 (0.07–4.94) 0.75 Paraplegia 0 (0.0) 1 (1.6) Stroke 0 (0.0) 11 (17.7) 0.11 (0.00–0.97) 0.046 Transient ischaemic attack 0 (0.0) 9 (14.5) 0.12 (0.00–1.12) 0.065 Recurrent nerve palsy 1 (3.3) 14 (22.6) 0.17 (0.02–0.78) 0.020 Renal failure/dialysis 4 (13.3) 11 (17.7) 1.21 (0.30–4.53) 0.78 Resternotomy for bleeding/tamponade 1 (3.3) 11 (17.7) 0.25 (0.03–1.24) 0.094 CI: confidence interval; OR: odds ratio. Statistically significant values are in bold (P < 0.05). Main causes of death were intracranial bleeding or ischaemia [n = 3 (25.0%)] and dissection-associated malperfusion or bleeding [n = 3 (25.0%)]. The single reported case of death in the zone 2 group occurred due to a urosepsis after an initial uneventful perioperative period, which was unrelated to the surgical technique. DISCUSSION The FET technique has become the treatment of choice for extensive thoracic aortic disease involving the arch and descending aorta as a single-stage procedure. The concept has been proven to achieve lasting results down to the stent graft end and to promote remodelling in acute type A aortic dissection [5]. Furthermore, additional endovascular aortic repair or surgical treatment of the downstream aorta is facilitated by providing an easy landing zone. However, the FET technique remains a challenging surgical technique and early results are still suboptimal [6–10]. Thus, several modifications have been proposed to facilitate the FET procedure and to improve early results. Zone 2 stent graft deployment The complexity of the FET procedure can be reduced by proximalization of the stent graft deployment in aortic arch zone 2, which simplifies the distal graft anastomosis. In zone 3 deployment, the LSA anastomosis may be the most challenging anastomosis due to the very deep intrathoracic localization, particularly when dissected or in patients with connective tissue disease [2, 11]. For this reason, we initially preferred to perform the LSA anastomosis during HCA as described by others [12]. By moving the distal stent graft anastomosis into zone 2, the distance within the operative field is much shorter and the anastomosis is technically easier compared to anastomoses in zone 3. Further advantages shown in this study are the significant reduced risk of recurrent nerve injury and shorter circulatory arrest times, and thus shorter spinal ischaemia times. In a multicentre study on early outcomes of patients treated with FET by using the E-vita open stent graft, a distal landing zone lower than T10 was an independent predictor of permanent spinal cord injury [8]. Other groups have also described an association between FET length and spinal cord injury [10, 12, 13]. Although the risk of spinal cord injury may be decreased by proximalization of the distal anastomosis into zone 2, our results showed no statistically significant differences in terms of paraplegia between the 2 groups. However, no patient presented with postoperative paraplegia and only one patient suffered from recurrent nerve injury in the zone 2 group. This patient underwent a redo operation after hemiarch replacement for acute type A dissection with rapid false lumen dilatation and huge aneurysmal formation of the distal anastomotic site. In this study, we could demonstrate significant shorter circulatory arrest and cerebral perfusion times in zone 2 stent graft deployment compared to zone 3 procedures because only the left common carotid and innominate artery have to be anastomosed using the second and first branches of the Thoraflex Hybrid prosthesis. Several studies reported longer circulatory arrest and/or cerebral perfusion times in open arch surgery as independent risk factors for higher rates of neurological injuries and poor outcome [14–16]. Leontyev et al. [8] showed that the duration of SACP >60 min was an independent predictor of early mortality. Reduced cerebral perfusion and circulatory arrest times in the ‘simplified FET’ group with zone 2 stent graft deployment were associated with a significant reduction in stroke rates. However, there are further potential reasons for the lower stroke rate in zone 2, e.g. improved learning curve and surgical experience, patient selection (more elective versus emergency cases) and because manipulation of calcified head vessels was avoided. Thus, we resected the supra-aortic vessels more distally from its origin using the branched technique to avoid cerebral embolization of tissue debris during SACP. Anastomosis of supra-aortic vessels At our centre, we completely altered our technique from an island to a branched graft technique for reimplantation of the supra-aortic vessels. Although an advantage of a branched technique as compared to an island technique has not been demonstrated, potential advantages are the reduction in circulatory arrest and lower body ischaemia time after stent graft deployment by using the antegrade perfusion side branch for arterial cannulation after completion of the distal anastomosis, which has been proven in our study. Furthermore, there is potentially a reduced risk of cerebral emboli by replacing the complete aortic arch and proximal arch vessels in severe atheromatous aneurysms, and avoiding island aneurysms in connective tissue disorders. The branched anastomoses to the innominate and left carotid arteries are usually easy to perform by a running suture technique and are easy to access for haemostasis due to better exposure. However, the LSA anastomosis is technically more challenging due to the deep intrathoracic localization. Pichlmaier et al. [11] recently described a novel Stent-Bridging technique for the anastomoses to the supra-aortic vessels. Here, the anastomoses to the left subclavian and to the left common carotid arteries were performed by only placing 2–4 aligning single sutures, followed by placing a covered stent to bridge the anastomosis. The authors found fewer bleeding complications and optimal alignment of the branches and target vessels. However, the limitation of this type of anastomoses is that it cannot be performed during reperfusion but only in circulatory arrest, as the perfusion arm of the FET-prosthesis is in close relation to the supra-aortic arms, which makes the insertion of the covered stents into the clamped FET-prosthesis impossible. Anastomosis of the left subclavian artery and cannulation technique When Tsagakis et al. [10] first described the proximalization of the distal anastomosis in FET procedures to zone 2 using the Jotec open hybrid prosthesis, they followed 2 different revascularization techniques for the LSA. Depending on the anatomy, they either transected and closed the LSA orifice and reimplanted the LSA into the aortic graft using an end-to-end anastomosis to an 8–12 mm vascular graft, or they performed an extra-anatomical bypass between the aortic graft and the left axillary artery in the left deltopectoral groove, introducing a vascular graft through the 2nd intercostal space. The management of the LSA revascularization at the origin of the vessel during FET procedures is often challenging, especially in patients with severe atherosclerosis and aortic dissection. Using our simplified FET technique, the exposure of the distal LSA via a left-sided supraclavicular approach addresses the complex anatomy of the deep origin of the LSA in the chest. In contrast to most surgeons in Europe who cannulate the right subclavian/axillary artery [17], we perform a cannulation of the distal LSA via this left supraclavicular incision using an 8-mm vascular graft. The graft is used both as arterial inflow for full body perfusion and for the blood supply to the left arm. The supraclavicular incision and the use of the LSA T-graft subsequently allow an easy and tensionless end-to-end anastomosis to the third branch of the Thoraflex prosthesis. Thus, the most difficult and time-consuming anastomosis between the third branch of the Thoraflex prosthesis and the origin of the LSA during HCA and SACP can be avoided. The LSA anastomosis is easily performed during reperfusion and rewarming of the patient, saving a substantial amount of time. Besides anatomic considerations, another further advantage of distal LSA graft anastomosis and cannulation is that even in cases with severe atherosclerotic aortic arch pathology, calcification of the distal LSA is usually absent. This may also explain the lower stroke rates. In the majority of patients who suffer from aortic dissection, the distal part of the LSA is free from dissection. However, if the distal LSA is dissected, we still use LSA cannulation for CPB, but fenestrate the dissection membrane to secure bidirectional perfusion. In these cases, proper arterial inflow and pressure has to be checked after initiation of extracorporeal circulation (ECC). If there are any concerns with arterial inflow, we strongly recommend direct aortic cannulation. Overall, the described simplified FET technique with stent graft deployment in arch zone 2, distal extra-anatomic LSA T-graft using the third branch of the Thoraflex prosthesis during reperfusion and left subclavian cannulation offers several advantages: Firstly, it reduces HCA and SACP times, hence reducing the risk of CVA; secondly early reperfusion is performed directly after stent graft deployment and distal anastomosis; thirdly, it facilitates the distal anastomosis in zone 2 and the distal LSA anastomosis during reperfusion; and finally, perfusion of the left arm and the upper spinal perfusion collateral network during HCA prevents postoperative paraplegia. Limitations The main limitations of our study were its retrospective nature and the small number of patients. In addition, there was a bias in terms of the underlying pathologies in zone 2 and zone 3 patients, which was corrected by multiple adjustment for confounding imbalances. However, the main focus of the study was to demonstrate the technical feasibility and safety of the simplified FET technique for the treatment of extensive thoracic aortic disease and to evaluate the short-term outcomes in terms of mortality and complication rates. For further evaluation, larger patient numbers are necessary to demonstrate statistical significance for the different surgical techniques. Results of zone 2 patients were significantly better compared to those of zone 3 patients. However, it must be taken into consideration that our FET technique was developed, improved and simplified from the experience we gained from the zone 3 cases. CONCLUSION Although the FET procedure remains a major surgery for treatment of extensive thoracic aortic diseases, the complexity and invasiveness of the procedure can be significantly reduced by stent graft deployment in aortic arch zone 2 combined with an extra-anatomic bypass to the distal LSA via a supraclavicular access during reperfusion. Simplifying and standardizing the FET procedure led to shorter HCA and SACP times and was therefore associated with significantly improved early outcomes. This makes the FET procedure safe, reproducible and easier to perform. ACKNOWLEDGEMENTS The authors thank Terumo Aortic for providing the Thoraflex™ Hybrid Plexus prosthesis illustration (Fig. 1). Conflict of interest: Christian Detter is a proctor for Terumo Aortic. All other authors declared no conflict of interest. REFERENCES 1 Ma W-G , Zheng J , Sun L-Z , Salamone G , Elefteriades JA. Open stented grafts for frozen elephant trunk technique: technical aspects and current outcomes . Aorta 2015 ; 3 : 122 – 35 . Google Scholar Crossref Search ADS PubMed 2 Tsagakis K , Dohle DS , Wendt D , Wiese W , Benedik J , Lieder H et al. Left subclavian artery rerouting and selective perfusion management in frozen elephant trunk surgery . Minim Invasive Ther Allied Technol 2015 ; 24 : 311 – 16 . Google Scholar PubMed 3 Hickey GL , Dunning J , Seifert B , Sodeck G , Carr MJ , Burger HU et al. Statistical and data reporting guidelines for the European Journal of Cardio-Thoracic Surgery and the Interactive CardioVascular and Thoracic Surgery . Eur J Cardiothorac Surg 2015 ; 48 : 180 – 93 . Google Scholar Crossref Search ADS PubMed 4 Bender R , Lange S. Adjusting for multiple testing—when and how? J Clin Epidemiol 2001 ; 54 : 343 – 9 . Google Scholar Crossref Search ADS PubMed 5 De Paulis R. Towards a better, complete treatment of aortic arch pathologies . Eur J Cardiothorac Surg 2017 ; 51 : i1 – 3 . Google Scholar Crossref Search ADS PubMed 6 Di Bartolomeo R , Murana G , Di Marco L , Alfonsi J , Gliozzi G , Amodio C et al. Is the frozen elephant trunk frozen? Gen Thorac Cardiovasc Surg 2018 ; 67 : 111 – 17 . Google Scholar Crossref Search ADS PubMed 7 Ius F , Fleissner F , Pichlmaier M , Karck M , Martens A , Haverich A et al. Total aortic arch replacement with the frozen elephant trunk technique: 10-year follow-up single-centre experience . Eur J Cardiothorac Surg 2013 ; 44 : 949 – 57 . Google Scholar Crossref Search ADS PubMed 8 Leontyev S , Tsagakis K , Pacini D , Di Bartolomeo R , Mohr FW , Weiss G et al. Impact of clinical factors and surgical techniques on early outcome of patients treated with frozen elephant trunk technique by using EVITA open stent-graft: results of a multicentre study . Eur J Cardiothorac Surg 2016 ; 49 : 660 – 6 . Google Scholar Crossref Search ADS PubMed 9 Shrestha M , Martens A , Kaufeld T , Beckmann E , Bertele S , Krueger H et al. Single-centre experience with the frozen elephant trunk technique in 251 patients over 15 years . Eur J Cardiothorac Surg 2017 ; 52 : 858 – 66 . Google Scholar Crossref Search ADS PubMed 10 Tsagakis K , Dohle D , Benedik J , Lieder H , Jakob H. Overall Essen’s experience with the E-vita open hybrid stent graft system and evolution of the surgical technique . Ann Cardiothorac Surg 2013 ; 2 : 612 – 20 . Google Scholar PubMed 11 Pichlmaier M , Luehr M , Rutkowski S , Fabry T , Guenther S , Hagl C et al. Aortic arch hybrid repair: Stent-Bridging of the Supra-Aortic Vessel Anastomoses (SAVSTEB) . Ann Thorac Surg 2017 ; 104 : e463 – 5 . Google Scholar Crossref Search ADS PubMed 12 Czerny M , Rylski B , Kari FA , Kreibich M , Morlock J , Scheumann J et al. Technical details making aortic arch replacement a safe procedure using the ThoraflexTM Hybrid prosthesis . Eur J Cardiothorac Surg 2017 ; 51 : i15 – 19 . Google Scholar Crossref Search ADS PubMed 13 Katayama K , Uchida N , Katayama A , Takahashi S , Takasaki T , Kurosaki T et al. Multiple factors predict the risk of spinal cord injury after the frozen elephant trunk technique for extended thoracic aortic disease . Eur J Cardiothor Surg 2015 ; 47 : 616 – 20 . Google Scholar Crossref Search ADS 14 Cefarelli M , Murana G , Surace GG , Castrovinci S , Jafrancesco G , Kelder JC et al. Elective aortic arch repair: factors influencing neurologic outcome in 791 patients . Ann Thorac Surg 2017 ; 104 : 2016 – 23 . Google Scholar Crossref Search ADS PubMed 15 Haldenwang PL , Bechtel M , Moustafine V , Buchwald D , Wippermann J , Wahlers T et al. State of the art in neuroprotection during acute type A aortic dissection repair . Perfusion 2012 ; 27 : 119 – 26 . Google Scholar Crossref Search ADS PubMed 16 Tong G , Zhang B , Zhou X , Tao Y , Yan T , Wang X et al. Bilateral versus unilateral antegrade cerebral perfusion in total arch replacement for type A aortic dissection . J Thorac Cardiovasc Surg 2017 ; 154 : 767 – 75 . Google Scholar Crossref Search ADS PubMed 17 De Paulis R , Czerny M , Weltert L , Bavaria J , Borger MA , Carrel TP et al. Current trends in cannulation and neuroprotection during surgery of the aortic arch in Europe . Eur J Cardiothorac Surg 2015 ; 47 : 917 – 23 . Google Scholar Crossref Search ADS PubMed © The Author(s) 2019. 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/open_access/funder_policies/chorus/standard_publication_model) http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png European Journal of Cardio-Thoracic Surgery Oxford University Press

Simplified frozen elephant trunk technique for combined open and endovascular treatment of extensive aortic diseases

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Oxford University Press
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© The Author(s) 2019. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
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1010-7940
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1873-734X
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10.1093/ejcts/ezz082
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Abstract

Abstract View largeDownload slide View largeDownload slide OBJECTIVES This study aims to analyse the impact of a simplified frozen elephant trunk (FET) technique on early outcome. METHODS Between October 2010 and August 2018, 92 consecutive patients (mean age 64.4 ± 12.2 years) underwent FET surgery. Underlying pathologies were thoracic aneurysm in 35 patients, acute aortic dissection in 25 patients and chronic dissection in 32 patients. Thirty patients underwent a simplified FET technique with deployment of the stent graft in arch zone 2 with an extra-anatomic bypass to the distal left subclavian artery using the third branch of the Thoraflex™ Hybrid Plexus prosthesis via a supraclavicular access during reperfusion. These patients were compared to 62 patients who received the conventional FET procedure, in which a distal anastomosis is performed in arch zone 3. RESULTS Circulatory arrest (41.7 ± 10.5 vs 76.5 ± 33.0 min; P < 0.001) and antegrade cerebral perfusion times (60.9 ± 13.5 vs 92.1 ± 33.1 min; P < 0.001) were significantly reduced in zone 2 vs zone 3 patients, respectively. The 30-day mortality rate was 3.3% (n = 1) in zone 2 patients vs 17.7% (n = 11) in zone 3 patients (P = 0.75). Stent deployment in zone 2 was associated with significantly reduced rates of postoperative stroke [zone 2: n = 0 (0.0%); zone 3: n = 11 (17.7%), P = 0.046] and recurrent nerve palsy [zone 2: n = 1 (3.3%); zone 3: n = 14 (22.6%), P = 0.020). CONCLUSIONS Simplifying the FET procedure leads to reduced circulatory arrest and cerebral perfusion times and improves early outcome. Aortic aneurysm, Type A aortic dissection, Aortic arch replacement, Frozen elephant trunk, Subclavian artery, Endovascular procedures INTRODUCTION The frozen elephant trunk (FET) procedure is a treatment for patients with extensive thoracic aortic disease involving the arch and descending aorta. Owing to the complex surgical technique, early outcome remains unsatisfactory with mortality rates ranging from 6.4% to 15.8%, despite modern cerebral perfusion strategies [1]. Traditionally, the distal anastomosis in FET surgery is performed in the aortic arch zone 3. The main issues using this technique are the challenging distal aortic and supra-aortic vessel anastomoses. Tsagakis et al. [2] described a surgical strategy where the distal anastomosis is moved to zone 2 or further proximal, thus reducing the surgical trauma during FET procedures. However, this requires time-consuming rerouting strategies for the sacrificed left subclavian artery (LSA) by performing an aortic-subclavian or a carotid-subclavian bypass. In this study, we present a simplified surgical technique, in which the distal hybrid graft anastomosis in aortic arch zone 2 and a distal LSA anastomosis using the third branch of the Terumo Aortic Thoraflex™ Hybrid Plexus prosthesis (Terumo Aortic, Inchinnan, Scotland, UK) via an additional left supraclavicular access are performed. We compare procedural data and early outcome of this simplified technique with those of the traditional approach. MATERIALS AND METHODS Patients From October 2010 to August 2018, 92 consecutive patients underwent replacement of the thoracic aorta using the FET technique at our centre. In 30 of the 92 patients, the distal anastomosis was performed in aortic arch zone 2, whereas 62 patients received the conventional FET procedure performing the distal anastomosis in aortic arch zone 3. The mean age of all patients was 64.4 ± 12.2 years, with 58.7% of patients being men. Mean EuroSCORE II was 12.2 ± 12.4. Arterial hypertension was the most prevalent comorbidity in 89.1% of patients. Underlying pathologies were extensive aortic aneurysms with involvement of the entire thoracic or thoraco-abdominal aorta in 38.0% of patients, chronic type A or B dissections in 34.8% of patients and acute type A dissections in 27.2% of patients. Sixteen patients suffered from a connective tissue disorder. Twenty-three of the 92 patients underwent FET as a redo procedure and 6 patients sustained an acute aortic rupture and were treated in a bailout situation. The baseline characteristics of both study groups are shown in Table 1. Table 1: Patient characteristics Baseline characteristics Zone 2 (n = 30) Zone 3 (n = 62) P-value Age (years), mean ± SD 64.2 ± 13.2 64.5 ± 11.8 0.908 Male gender, n (%) 16 (53.3) 38 (61.3) 0.467 Arterial hypertension, n (%) 27 (90.0) 55 (88.7) 1.000 Genetic aortic syndrome, n (%) 6 (20.0) 10 (16.1) 0.646 EuroSCORE II, mean ± SD 7.6 ± 3.4 14.4 ± 14.4 <0.001 Pathologies, n (%)  Extensive thoracic aneurysm 15 (50.0) 20 (32.3) 0.100  Acute type A dissection 2 (6.7) 23 (37.1) 0.002  Chronic type A/B dissection 13 (43.3) 19 (30.6) 0.231 Acute aortic rupture, n (%) 0 (0.0) 6 (9.7) 0.172 Emergency procedures (<24 h), n (%) 2 (6.7) 21 (33.9) 0.005 Redo surgery, n (%) 10 (33.3) 13 (21.0) 0.199 Baseline characteristics Zone 2 (n = 30) Zone 3 (n = 62) P-value Age (years), mean ± SD 64.2 ± 13.2 64.5 ± 11.8 0.908 Male gender, n (%) 16 (53.3) 38 (61.3) 0.467 Arterial hypertension, n (%) 27 (90.0) 55 (88.7) 1.000 Genetic aortic syndrome, n (%) 6 (20.0) 10 (16.1) 0.646 EuroSCORE II, mean ± SD 7.6 ± 3.4 14.4 ± 14.4 <0.001 Pathologies, n (%)  Extensive thoracic aneurysm 15 (50.0) 20 (32.3) 0.100  Acute type A dissection 2 (6.7) 23 (37.1) 0.002  Chronic type A/B dissection 13 (43.3) 19 (30.6) 0.231 Acute aortic rupture, n (%) 0 (0.0) 6 (9.7) 0.172 Emergency procedures (<24 h), n (%) 2 (6.7) 21 (33.9) 0.005 Redo surgery, n (%) 10 (33.3) 13 (21.0) 0.199 SD: standard deviation. Statistically significant values are in bold (P < 0.05). Table 1: Patient characteristics Baseline characteristics Zone 2 (n = 30) Zone 3 (n = 62) P-value Age (years), mean ± SD 64.2 ± 13.2 64.5 ± 11.8 0.908 Male gender, n (%) 16 (53.3) 38 (61.3) 0.467 Arterial hypertension, n (%) 27 (90.0) 55 (88.7) 1.000 Genetic aortic syndrome, n (%) 6 (20.0) 10 (16.1) 0.646 EuroSCORE II, mean ± SD 7.6 ± 3.4 14.4 ± 14.4 <0.001 Pathologies, n (%)  Extensive thoracic aneurysm 15 (50.0) 20 (32.3) 0.100  Acute type A dissection 2 (6.7) 23 (37.1) 0.002  Chronic type A/B dissection 13 (43.3) 19 (30.6) 0.231 Acute aortic rupture, n (%) 0 (0.0) 6 (9.7) 0.172 Emergency procedures (<24 h), n (%) 2 (6.7) 21 (33.9) 0.005 Redo surgery, n (%) 10 (33.3) 13 (21.0) 0.199 Baseline characteristics Zone 2 (n = 30) Zone 3 (n = 62) P-value Age (years), mean ± SD 64.2 ± 13.2 64.5 ± 11.8 0.908 Male gender, n (%) 16 (53.3) 38 (61.3) 0.467 Arterial hypertension, n (%) 27 (90.0) 55 (88.7) 1.000 Genetic aortic syndrome, n (%) 6 (20.0) 10 (16.1) 0.646 EuroSCORE II, mean ± SD 7.6 ± 3.4 14.4 ± 14.4 <0.001 Pathologies, n (%)  Extensive thoracic aneurysm 15 (50.0) 20 (32.3) 0.100  Acute type A dissection 2 (6.7) 23 (37.1) 0.002  Chronic type A/B dissection 13 (43.3) 19 (30.6) 0.231 Acute aortic rupture, n (%) 0 (0.0) 6 (9.7) 0.172 Emergency procedures (<24 h), n (%) 2 (6.7) 21 (33.9) 0.005 Redo surgery, n (%) 10 (33.3) 13 (21.0) 0.199 SD: standard deviation. Statistically significant values are in bold (P < 0.05). Patient data were prospectively collected using our dedicated institutional aortic database. Clinical and follow-up characteristics were retrospectively analysed. Surgical techniques All operations were performed via a median sternotomy. Conventional frozen elephant trunk technique: distal anastomosis in aortic arch zone 3 Sixty-two patients of the 92 patients received the conventional FET procedure, in which the distal anastomosis is performed in aortic arch zone 3. For cardiopulmonary bypass (CPB), cannulation of the subclavian artery (n = 13), innominate artery (n = 20), femoral artery (n = 1) or direct cannulation of the ascending aorta/arch using the Seldinger’s technique (n = 28) was performed. Venous drainage was obtained by cannulation of the right atrium. In redo operations, the right femoral vein was cannulated percutaneously using the Seldinger’s technique and advanced towards the superior vena cava under transoesophageal echocardiography guidance. The left ventricle was vented via the right superior pulmonary vein. Antegrade and retrograde blood cardioplegia was used in all patients for myocardial protection. Cerebral protection was performed in all patients using moderate hypothermic circulatory arrest (HCA) between 24 and 26°C and bilateral selective antegrade cerebral perfusion (SACP). Arterial blood pressure was measured in the right radial and femoral artery. Near infrared spectroscopy was used to monitor cerebral perfusion by measuring oxygen saturation. Continuous carbon dioxide insufflation was used in all patients. In right subclavian or innominate artery cannulation, the brachiocephalic trunk was proximally clamped and right-sided unilateral SACP was started after the intended temperature had been reached. The ascending aorta and proximal aortic arch were transected, and a cerebral perfusion catheter was inserted into the left common carotid artery to provide bilateral SACP. In case of direct cannulation of the ascending aorta/arch, 2 catheters were inserted into the innominate and left carotid artery for bilateral SACP. The perfusion catheters were secured using tourniquets to prevent migration and embolization of tissue debris. The cerebral flow rate was set to 10–15 ml/kg/min with a mean pressure of 50–70 mmHg. The aortic arch was resected distally from the LSA origin. A strong aortic stump of the proximal descending aorta was created to facilitate the distal anastomosis. In acute and chronic dissection, the false lumen was occluded using interrupted U-stitches with pledgets to avoid a purse-string effect. The compacted stent section of the prosthesis was smoothly inserted into the descending aorta after proper bending of the distal stent part to fit distal aortic anatomy, thereby avoiding distal aortic perforation or mobilization of any thrombus that may have formed. In chronic dissections or patients with a kinked or tortuous aorta, a guidewire was inserted into the true lumen guided by echocardiography. The delivery system was removed and the self-expanding FET stent deployed. In all cases, the distal graft anastomosis with the proximal descending aortic stump was performed using a 3–0 polypropylene running suture. A large piece of Teflon felt was used on the outside of the aorta. BioGlue (CryoLife Inc., Kennesaw, GA, USA) was applied after performing the distal anastomosis during circulatory arrest. In 11 patients, the Jotec E-vita open plus hybrid prosthesis (Jotec, Hechingen, Germany) and in 51 patients, the Terumo Aortic Thoraflex Hybrid Plexus prosthesis was used. The supra-aortic vessels were reimplanted on the aortic arch graft using the classical island technique in all 11 patients with the E-vita open prosthesis and in the initial 8 patients who had the Thoraflex Hybrid prosthesis implanted. The reason for using the island technique was due to the fact that all implanting surgeons were accustomed and trained to perform this technique. In the following 43 patients, we changed to the branched technique. In these cases, all 3 head vessels were transected and replaced using the 3 branches of the Thoraflex Hybrid prosthesis (branched technique). Finally, total aortic arch and ascending replacement was completed by the proximal anastomosis to the ascending aortic stump or an aortic root graft, depending on the proximal aortic procedure. Additional proximal aortic and concomitant procedures are summarized in Table 2. Subsequently, the heart was deaired and the aortic clamp removed. Table 2: Surgical technique and additional procedures Arch zone 2 (n = 30), n (%) Arch zone 3 (n = 62), n (%) P-value FET hybrid prosthesis 0.014  Jotec E-vita open plus hybrid 0 (0.0) 11 (17.7)  Thoraflex™ Hybrid Plexus 30 (100.0) 51 (82.3) Supra-aortic vessels 0.001  Island technique 0 (0.0) 19 (30.6)  Branched technique 30 (100.0) 43 (69.4) Ascending procedures  Supracoronary replacement 24 (80.0) 42 (67.7) 0.221  Bentall procedure 4 (13.3) 13 (21.0) 0.376  David procedure 2 (6.7) 6 (9.7) 1.000 Additional CABG 2 (6.7) 5 (8.1) 1.000 Additional TVR 0 (0.0) 1 (1.6) 1.000 Arch zone 2 (n = 30), n (%) Arch zone 3 (n = 62), n (%) P-value FET hybrid prosthesis 0.014  Jotec E-vita open plus hybrid 0 (0.0) 11 (17.7)  Thoraflex™ Hybrid Plexus 30 (100.0) 51 (82.3) Supra-aortic vessels 0.001  Island technique 0 (0.0) 19 (30.6)  Branched technique 30 (100.0) 43 (69.4) Ascending procedures  Supracoronary replacement 24 (80.0) 42 (67.7) 0.221  Bentall procedure 4 (13.3) 13 (21.0) 0.376  David procedure 2 (6.7) 6 (9.7) 1.000 Additional CABG 2 (6.7) 5 (8.1) 1.000 Additional TVR 0 (0.0) 1 (1.6) 1.000 CABG: coronary artery bypass grafting; FET: frozen elephant trunk; TVR: tricuspid valve repair. Statistically significant values are in bold (P < 0.05). Table 2: Surgical technique and additional procedures Arch zone 2 (n = 30), n (%) Arch zone 3 (n = 62), n (%) P-value FET hybrid prosthesis 0.014  Jotec E-vita open plus hybrid 0 (0.0) 11 (17.7)  Thoraflex™ Hybrid Plexus 30 (100.0) 51 (82.3) Supra-aortic vessels 0.001  Island technique 0 (0.0) 19 (30.6)  Branched technique 30 (100.0) 43 (69.4) Ascending procedures  Supracoronary replacement 24 (80.0) 42 (67.7) 0.221  Bentall procedure 4 (13.3) 13 (21.0) 0.376  David procedure 2 (6.7) 6 (9.7) 1.000 Additional CABG 2 (6.7) 5 (8.1) 1.000 Additional TVR 0 (0.0) 1 (1.6) 1.000 Arch zone 2 (n = 30), n (%) Arch zone 3 (n = 62), n (%) P-value FET hybrid prosthesis 0.014  Jotec E-vita open plus hybrid 0 (0.0) 11 (17.7)  Thoraflex™ Hybrid Plexus 30 (100.0) 51 (82.3) Supra-aortic vessels 0.001  Island technique 0 (0.0) 19 (30.6)  Branched technique 30 (100.0) 43 (69.4) Ascending procedures  Supracoronary replacement 24 (80.0) 42 (67.7) 0.221  Bentall procedure 4 (13.3) 13 (21.0) 0.376  David procedure 2 (6.7) 6 (9.7) 1.000 Additional CABG 2 (6.7) 5 (8.1) 1.000 Additional TVR 0 (0.0) 1 (1.6) 1.000 CABG: coronary artery bypass grafting; FET: frozen elephant trunk; TVR: tricuspid valve repair. Statistically significant values are in bold (P < 0.05). Simplified frozen elephant trunk technique: distal anastomosis in aortic arch zone 2 Using the simplified FET technique, the LSA was exposed via a left-sided supraclavicular approach (Fig. 1A). An 8-mm Dacron graft (Gelweave™ prosthesis, Terumo Aortic) was sutured to the anterior side of the LSA in a T-graft fashion (LSA T-graft) with slight downwards angulation of the prosthesis to avoid kinking of the graft (Fig. 2A). The graft was cannulated using a 22-Fr arterial inflow cannula for full body perfusion and blood supply to the left arm (Fig. 1B). Venous drainage was obtained by cannulation of the right atrium. Figure 1: View largeDownload slide The simplified frozen elephant trunk technique (schematic illustration). (A) Exposure of the LSA via a left-sided supraclavicular approach. (B) An 8-mm Dacron graft is sutured to the LSA (LSA T-graft) and cannulated using a 22-Fr arterial cannula. (C) The first and second branches of the TH prosthesis are anastomosed to the innominate and left common carotid artery. (D) During reperfusion, the Dacron prosthesis to the LSA is shortened and anastomosed to the third branch of the TH prosthesis in an end-to-end fashion. ECC: extracorporeal circulation; LSA: left subclavian artery; TH: Thoraflex™ Hybrid. Figure 1: View largeDownload slide The simplified frozen elephant trunk technique (schematic illustration). (A) Exposure of the LSA via a left-sided supraclavicular approach. (B) An 8-mm Dacron graft is sutured to the LSA (LSA T-graft) and cannulated using a 22-Fr arterial cannula. (C) The first and second branches of the TH prosthesis are anastomosed to the innominate and left common carotid artery. (D) During reperfusion, the Dacron prosthesis to the LSA is shortened and anastomosed to the third branch of the TH prosthesis in an end-to-end fashion. ECC: extracorporeal circulation; LSA: left subclavian artery; TH: Thoraflex™ Hybrid. Figure 2: View largeDownload slide Intraoperative images. (A) Anastomosis of an 8-mm Dacron prosthesis with the LSA (LSA T-graft). (B) LSA T-graft (cannulated with a 22-Fr. arterial cannula) and third branch of the Thoraflex™ Hybrid prosthesis. (C) The third branch is pulled below the clavicle and anastomosed with the LSA T-graft. (D) Thoraflex Hybrid prosthesis in situ after finishing all anastomoses. LSA: left subclavian artery. Figure 2: View largeDownload slide Intraoperative images. (A) Anastomosis of an 8-mm Dacron prosthesis with the LSA (LSA T-graft). (B) LSA T-graft (cannulated with a 22-Fr. arterial cannula) and third branch of the Thoraflex™ Hybrid prosthesis. (C) The third branch is pulled below the clavicle and anastomosed with the LSA T-graft. (D) Thoraflex Hybrid prosthesis in situ after finishing all anastomoses. LSA: left subclavian artery. During moderate HCA and SACP, the aortic arch was transected between the left common carotid artery and the LSA. The origin of the LSA was ligated twice using 2/0 ethibond sutures. The compacted stent section of the Thoraflex Hybrid prosthesis was inserted into the distal arch and deployed in the descending aorta with overstenting the origin of the LSA. The distal graft anastomosis was performed in zone 2 using the sewing collar of the Thoraflex Hybrid prosthesis. After completion of the distal anastomosis, the perfusion side branch of the prosthesis was cannulated and CPB restarted to provide early antegrade lower body perfusion. Subsequently, the Thoraflex Hybrid prosthesis and the 3 side branches were deaired, clamped and the distal anastomosis was checked for bleeding under full pressure. Thereafter, the second and first branches of the prosthesis were anastomosed to the left common carotid and innominate artery using 5.0 and 4.0 Prolene running sutures, respectively, while slow rewarming of the patient was initiated. The proximal end of the hybrid graft was finally anastomosed either to the ascending aorta or an aortic root graft, if indicated (Fig. 1C). After deairing, the aortic clamp was removed and myocardial perfusion started. During reperfusion and rewarming on the beating heart, a retroclavicular tunnel between the left supraclavicular incision and the upper thoracic aperture was created by blunt dissection. The third side branch of the prosthesis was pulled upwards below the left sternoclavicular joint to the left supraclavicular incision. To complete the procedure, the LSA T-graft previously used for arterial inflow, was shortened and anastomosed to the third branch of the Thoraflex Hybrid prosthesis in an end-to-end fashion (Figs 1D and 2C). A postoperative computed tomography (CT) scan is shown in Fig. 3. Figure 3: View largeDownload slide Postoperative computed tomography scan. (A) Ventral view. Heart and supra-aortic head vessels after frozen elephant trunk surgery. (B) Zoomed ventral view. The IA and the LCA were transected and replaced using the first and second branches of the Thoraflex™ Hybrid prosthesis. The third branch of the prosthesis was anastomosed in an end-to-end fashion to the Dacron graft, which was sutured to the LSA as T-graft. (C) Zoomed left cranial view for better visualization of the supra-aortic vessels and ligated LSA’s origin. IA: innominate artery; LCA: left common carotid artery; LSA: left subclavian artery. Figure 3: View largeDownload slide Postoperative computed tomography scan. (A) Ventral view. Heart and supra-aortic head vessels after frozen elephant trunk surgery. (B) Zoomed ventral view. The IA and the LCA were transected and replaced using the first and second branches of the Thoraflex™ Hybrid prosthesis. The third branch of the prosthesis was anastomosed in an end-to-end fashion to the Dacron graft, which was sutured to the LSA as T-graft. (C) Zoomed left cranial view for better visualization of the supra-aortic vessels and ligated LSA’s origin. IA: innominate artery; LCA: left common carotid artery; LSA: left subclavian artery. Stent graft sizing and length Stent graft sizing of the hybrid prosthesis was made according to the preoperative CT scan with 10% oversizing in thoracic aneurysms based on the diameter of the descending aorta to prevent the occurrence of type Ib endoleaks. In acute aortic dissections and patients with connective tissue disorders, we measured the total diameter of the aorta and no oversizing was performed. In chronic dissections, the stent graft sizing was performed according to the dimensions of the true lumen measured in the CT scan and by intraoperative sizing. In the first 11 patients, the E-vita open prosthesis with a stent length of 150 mm was used. Since April 2013, the Thoraflex Hybrid prostheses were implanted. Initially, we used the 100 mm stent length in most of the patients to avoid a distal landing zone lower than T10. In zone 2 placement, however, we used the 150 mm stent length due to the fact that the placement of the stent graft is at least 3–5 cm higher. Statistical analysis Baseline categorical variables were summarized by frequencies and percentages. These were compared between study groups using the Fisher’s exact test. Continuous variables were described by mean ± standard deviation and compared between study groups using the 2-sided Student’s t-test. As this is a non-randomized study, baseline differences between groups in relevant prognostic factors can occur, which can bias the observed intervention effect. Therefore, we reported treatment effects adjusted for factors, which differ between groups according to Hickey et al. [3]. Continuous outcomes, e.g. intraoperative data on timings, were analysed in a multivariable linear model and adjusted differences and confidence intervals (CIs) were reported. Binary outcomes, e.g. 30-day mortality and postoperative complications were analysed using multivariable logistic regression models applying Firth’s correction to the likelihood to account for the small sample size and the limited number of events. Adjusted odds ratios (ORs), 95% CIs and P-values were reported from these models. The level of significance for all analyses was set at alpha = 0.05. Because this was an exploratory study, no adjustment for multiple testing was performed [4]. Statistical analyses were performed using IBM SPSS Version 24.0.0.0 and the logistf-package in R 3-4.4. RESULTS In 30 of the 92 FET cases, the distal anastomosis of the stent graft was performed in the aortic arch zone 2. Zone 2 cases differ from zone 3 cases at baseline in terms of EuroSCORE II and the incidence of acute type A dissections. Therefore, these factors were used as confounders. In zone 2 cases, the circulatory arrest time (adjusted delta = −27.8 min, 95% CI −40.1 to −15.4; P < 0.001) and the cerebral perfusion time (adjusted delta = −27.5 min, 95% CI −40.8 to −14.2; P < 0.001) were significantly reduced when compared to cases with stent deployment in aortic arch zone 3 (Table 3). The stent deployment in zone 2 was associated with significantly reduced rates of postoperative stroke [zone 2: n = 0 (0.0%); zone 3 n = 11 (17.7%), adjusted OR = 0.11, 95% CI 0.00–0.97; P = 0.046] and recurrent nerve palsy [zone 2: n = 2 (3.3%); zone 3: n = 14 (22.6%), adjusted OR = 0.17, 95% CI 0.02–0.78; P = 0.020]. Overall, 30-day mortality including other perioperative complications, such as paraplegia, transient ischaemic attack, renal failure and resternotomy for bleeding or tamponade were less frequent in patients with stent deployment in zone 2 as compared to zone 3 patients. However, this data did not reach statistical significance (Table 4). Table 3: Intraoperative data Arch zone 2 (n = 30), mean ± SD Arch zone 3 (n = 62), mean ± SD Difference (95% CI) P-value Extracorporeal circulation time (min) 231.7 ± 59.0 285.2 ± 82.5 −26.2 (−58.5 to 6.0) 0.11 Aortic clamp time (min) 114.4 ± 38.6 152.9 ± 60.4 −20.5 (−43.8 to 2.8) 0.083 Circulatory arrest time (min) 41.7 ± 10.5 76.5 ± 33.0 −27.8 (−40.1 to −15.4) <0.001 Cerebral perfusion time (min) 60.9 ± 13.5 92.1 ± 33.1 −27.5 (−40.8 to −14.2) <0.001 Deepest body temperature (°C) 23.9 ± 1.2 23.8 ± 1.9 −0.2 (−1.0 to 0.7) 0.71 Arch zone 2 (n = 30), mean ± SD Arch zone 3 (n = 62), mean ± SD Difference (95% CI) P-value Extracorporeal circulation time (min) 231.7 ± 59.0 285.2 ± 82.5 −26.2 (−58.5 to 6.0) 0.11 Aortic clamp time (min) 114.4 ± 38.6 152.9 ± 60.4 −20.5 (−43.8 to 2.8) 0.083 Circulatory arrest time (min) 41.7 ± 10.5 76.5 ± 33.0 −27.8 (−40.1 to −15.4) <0.001 Cerebral perfusion time (min) 60.9 ± 13.5 92.1 ± 33.1 −27.5 (−40.8 to −14.2) <0.001 Deepest body temperature (°C) 23.9 ± 1.2 23.8 ± 1.9 −0.2 (−1.0 to 0.7) 0.71 SD is reported as the measure of variability. Statistically significant values are in bold (P < 0.05). CI: confidence interval; SD: standard deviation. Table 3: Intraoperative data Arch zone 2 (n = 30), mean ± SD Arch zone 3 (n = 62), mean ± SD Difference (95% CI) P-value Extracorporeal circulation time (min) 231.7 ± 59.0 285.2 ± 82.5 −26.2 (−58.5 to 6.0) 0.11 Aortic clamp time (min) 114.4 ± 38.6 152.9 ± 60.4 −20.5 (−43.8 to 2.8) 0.083 Circulatory arrest time (min) 41.7 ± 10.5 76.5 ± 33.0 −27.8 (−40.1 to −15.4) <0.001 Cerebral perfusion time (min) 60.9 ± 13.5 92.1 ± 33.1 −27.5 (−40.8 to −14.2) <0.001 Deepest body temperature (°C) 23.9 ± 1.2 23.8 ± 1.9 −0.2 (−1.0 to 0.7) 0.71 Arch zone 2 (n = 30), mean ± SD Arch zone 3 (n = 62), mean ± SD Difference (95% CI) P-value Extracorporeal circulation time (min) 231.7 ± 59.0 285.2 ± 82.5 −26.2 (−58.5 to 6.0) 0.11 Aortic clamp time (min) 114.4 ± 38.6 152.9 ± 60.4 −20.5 (−43.8 to 2.8) 0.083 Circulatory arrest time (min) 41.7 ± 10.5 76.5 ± 33.0 −27.8 (−40.1 to −15.4) <0.001 Cerebral perfusion time (min) 60.9 ± 13.5 92.1 ± 33.1 −27.5 (−40.8 to −14.2) <0.001 Deepest body temperature (°C) 23.9 ± 1.2 23.8 ± 1.9 −0.2 (−1.0 to 0.7) 0.71 SD is reported as the measure of variability. Statistically significant values are in bold (P < 0.05). CI: confidence interval; SD: standard deviation. Table 4: Early mortality and postoperative complications Arch zone 2 (n = 30), n (%) Arch zone 3 (n = 62), n (%) OR (95% CI) P-value Overall 30-day mortality 1 (3.3) 11 (17.7) 0.73 (0.07–4.94) 0.75 Paraplegia 0 (0.0) 1 (1.6) Stroke 0 (0.0) 11 (17.7) 0.11 (0.00–0.97) 0.046 Transient ischaemic attack 0 (0.0) 9 (14.5) 0.12 (0.00–1.12) 0.065 Recurrent nerve palsy 1 (3.3) 14 (22.6) 0.17 (0.02–0.78) 0.020 Renal failure/dialysis 4 (13.3) 11 (17.7) 1.21 (0.30–4.53) 0.78 Resternotomy for bleeding/tamponade 1 (3.3) 11 (17.7) 0.25 (0.03–1.24) 0.094 Arch zone 2 (n = 30), n (%) Arch zone 3 (n = 62), n (%) OR (95% CI) P-value Overall 30-day mortality 1 (3.3) 11 (17.7) 0.73 (0.07–4.94) 0.75 Paraplegia 0 (0.0) 1 (1.6) Stroke 0 (0.0) 11 (17.7) 0.11 (0.00–0.97) 0.046 Transient ischaemic attack 0 (0.0) 9 (14.5) 0.12 (0.00–1.12) 0.065 Recurrent nerve palsy 1 (3.3) 14 (22.6) 0.17 (0.02–0.78) 0.020 Renal failure/dialysis 4 (13.3) 11 (17.7) 1.21 (0.30–4.53) 0.78 Resternotomy for bleeding/tamponade 1 (3.3) 11 (17.7) 0.25 (0.03–1.24) 0.094 CI: confidence interval; OR: odds ratio. Statistically significant values are in bold (P < 0.05). Table 4: Early mortality and postoperative complications Arch zone 2 (n = 30), n (%) Arch zone 3 (n = 62), n (%) OR (95% CI) P-value Overall 30-day mortality 1 (3.3) 11 (17.7) 0.73 (0.07–4.94) 0.75 Paraplegia 0 (0.0) 1 (1.6) Stroke 0 (0.0) 11 (17.7) 0.11 (0.00–0.97) 0.046 Transient ischaemic attack 0 (0.0) 9 (14.5) 0.12 (0.00–1.12) 0.065 Recurrent nerve palsy 1 (3.3) 14 (22.6) 0.17 (0.02–0.78) 0.020 Renal failure/dialysis 4 (13.3) 11 (17.7) 1.21 (0.30–4.53) 0.78 Resternotomy for bleeding/tamponade 1 (3.3) 11 (17.7) 0.25 (0.03–1.24) 0.094 Arch zone 2 (n = 30), n (%) Arch zone 3 (n = 62), n (%) OR (95% CI) P-value Overall 30-day mortality 1 (3.3) 11 (17.7) 0.73 (0.07–4.94) 0.75 Paraplegia 0 (0.0) 1 (1.6) Stroke 0 (0.0) 11 (17.7) 0.11 (0.00–0.97) 0.046 Transient ischaemic attack 0 (0.0) 9 (14.5) 0.12 (0.00–1.12) 0.065 Recurrent nerve palsy 1 (3.3) 14 (22.6) 0.17 (0.02–0.78) 0.020 Renal failure/dialysis 4 (13.3) 11 (17.7) 1.21 (0.30–4.53) 0.78 Resternotomy for bleeding/tamponade 1 (3.3) 11 (17.7) 0.25 (0.03–1.24) 0.094 CI: confidence interval; OR: odds ratio. Statistically significant values are in bold (P < 0.05). Main causes of death were intracranial bleeding or ischaemia [n = 3 (25.0%)] and dissection-associated malperfusion or bleeding [n = 3 (25.0%)]. The single reported case of death in the zone 2 group occurred due to a urosepsis after an initial uneventful perioperative period, which was unrelated to the surgical technique. DISCUSSION The FET technique has become the treatment of choice for extensive thoracic aortic disease involving the arch and descending aorta as a single-stage procedure. The concept has been proven to achieve lasting results down to the stent graft end and to promote remodelling in acute type A aortic dissection [5]. Furthermore, additional endovascular aortic repair or surgical treatment of the downstream aorta is facilitated by providing an easy landing zone. However, the FET technique remains a challenging surgical technique and early results are still suboptimal [6–10]. Thus, several modifications have been proposed to facilitate the FET procedure and to improve early results. Zone 2 stent graft deployment The complexity of the FET procedure can be reduced by proximalization of the stent graft deployment in aortic arch zone 2, which simplifies the distal graft anastomosis. In zone 3 deployment, the LSA anastomosis may be the most challenging anastomosis due to the very deep intrathoracic localization, particularly when dissected or in patients with connective tissue disease [2, 11]. For this reason, we initially preferred to perform the LSA anastomosis during HCA as described by others [12]. By moving the distal stent graft anastomosis into zone 2, the distance within the operative field is much shorter and the anastomosis is technically easier compared to anastomoses in zone 3. Further advantages shown in this study are the significant reduced risk of recurrent nerve injury and shorter circulatory arrest times, and thus shorter spinal ischaemia times. In a multicentre study on early outcomes of patients treated with FET by using the E-vita open stent graft, a distal landing zone lower than T10 was an independent predictor of permanent spinal cord injury [8]. Other groups have also described an association between FET length and spinal cord injury [10, 12, 13]. Although the risk of spinal cord injury may be decreased by proximalization of the distal anastomosis into zone 2, our results showed no statistically significant differences in terms of paraplegia between the 2 groups. However, no patient presented with postoperative paraplegia and only one patient suffered from recurrent nerve injury in the zone 2 group. This patient underwent a redo operation after hemiarch replacement for acute type A dissection with rapid false lumen dilatation and huge aneurysmal formation of the distal anastomotic site. In this study, we could demonstrate significant shorter circulatory arrest and cerebral perfusion times in zone 2 stent graft deployment compared to zone 3 procedures because only the left common carotid and innominate artery have to be anastomosed using the second and first branches of the Thoraflex Hybrid prosthesis. Several studies reported longer circulatory arrest and/or cerebral perfusion times in open arch surgery as independent risk factors for higher rates of neurological injuries and poor outcome [14–16]. Leontyev et al. [8] showed that the duration of SACP >60 min was an independent predictor of early mortality. Reduced cerebral perfusion and circulatory arrest times in the ‘simplified FET’ group with zone 2 stent graft deployment were associated with a significant reduction in stroke rates. However, there are further potential reasons for the lower stroke rate in zone 2, e.g. improved learning curve and surgical experience, patient selection (more elective versus emergency cases) and because manipulation of calcified head vessels was avoided. Thus, we resected the supra-aortic vessels more distally from its origin using the branched technique to avoid cerebral embolization of tissue debris during SACP. Anastomosis of supra-aortic vessels At our centre, we completely altered our technique from an island to a branched graft technique for reimplantation of the supra-aortic vessels. Although an advantage of a branched technique as compared to an island technique has not been demonstrated, potential advantages are the reduction in circulatory arrest and lower body ischaemia time after stent graft deployment by using the antegrade perfusion side branch for arterial cannulation after completion of the distal anastomosis, which has been proven in our study. Furthermore, there is potentially a reduced risk of cerebral emboli by replacing the complete aortic arch and proximal arch vessels in severe atheromatous aneurysms, and avoiding island aneurysms in connective tissue disorders. The branched anastomoses to the innominate and left carotid arteries are usually easy to perform by a running suture technique and are easy to access for haemostasis due to better exposure. However, the LSA anastomosis is technically more challenging due to the deep intrathoracic localization. Pichlmaier et al. [11] recently described a novel Stent-Bridging technique for the anastomoses to the supra-aortic vessels. Here, the anastomoses to the left subclavian and to the left common carotid arteries were performed by only placing 2–4 aligning single sutures, followed by placing a covered stent to bridge the anastomosis. The authors found fewer bleeding complications and optimal alignment of the branches and target vessels. However, the limitation of this type of anastomoses is that it cannot be performed during reperfusion but only in circulatory arrest, as the perfusion arm of the FET-prosthesis is in close relation to the supra-aortic arms, which makes the insertion of the covered stents into the clamped FET-prosthesis impossible. Anastomosis of the left subclavian artery and cannulation technique When Tsagakis et al. [10] first described the proximalization of the distal anastomosis in FET procedures to zone 2 using the Jotec open hybrid prosthesis, they followed 2 different revascularization techniques for the LSA. Depending on the anatomy, they either transected and closed the LSA orifice and reimplanted the LSA into the aortic graft using an end-to-end anastomosis to an 8–12 mm vascular graft, or they performed an extra-anatomical bypass between the aortic graft and the left axillary artery in the left deltopectoral groove, introducing a vascular graft through the 2nd intercostal space. The management of the LSA revascularization at the origin of the vessel during FET procedures is often challenging, especially in patients with severe atherosclerosis and aortic dissection. Using our simplified FET technique, the exposure of the distal LSA via a left-sided supraclavicular approach addresses the complex anatomy of the deep origin of the LSA in the chest. In contrast to most surgeons in Europe who cannulate the right subclavian/axillary artery [17], we perform a cannulation of the distal LSA via this left supraclavicular incision using an 8-mm vascular graft. The graft is used both as arterial inflow for full body perfusion and for the blood supply to the left arm. The supraclavicular incision and the use of the LSA T-graft subsequently allow an easy and tensionless end-to-end anastomosis to the third branch of the Thoraflex prosthesis. Thus, the most difficult and time-consuming anastomosis between the third branch of the Thoraflex prosthesis and the origin of the LSA during HCA and SACP can be avoided. The LSA anastomosis is easily performed during reperfusion and rewarming of the patient, saving a substantial amount of time. Besides anatomic considerations, another further advantage of distal LSA graft anastomosis and cannulation is that even in cases with severe atherosclerotic aortic arch pathology, calcification of the distal LSA is usually absent. This may also explain the lower stroke rates. In the majority of patients who suffer from aortic dissection, the distal part of the LSA is free from dissection. However, if the distal LSA is dissected, we still use LSA cannulation for CPB, but fenestrate the dissection membrane to secure bidirectional perfusion. In these cases, proper arterial inflow and pressure has to be checked after initiation of extracorporeal circulation (ECC). If there are any concerns with arterial inflow, we strongly recommend direct aortic cannulation. Overall, the described simplified FET technique with stent graft deployment in arch zone 2, distal extra-anatomic LSA T-graft using the third branch of the Thoraflex prosthesis during reperfusion and left subclavian cannulation offers several advantages: Firstly, it reduces HCA and SACP times, hence reducing the risk of CVA; secondly early reperfusion is performed directly after stent graft deployment and distal anastomosis; thirdly, it facilitates the distal anastomosis in zone 2 and the distal LSA anastomosis during reperfusion; and finally, perfusion of the left arm and the upper spinal perfusion collateral network during HCA prevents postoperative paraplegia. Limitations The main limitations of our study were its retrospective nature and the small number of patients. In addition, there was a bias in terms of the underlying pathologies in zone 2 and zone 3 patients, which was corrected by multiple adjustment for confounding imbalances. However, the main focus of the study was to demonstrate the technical feasibility and safety of the simplified FET technique for the treatment of extensive thoracic aortic disease and to evaluate the short-term outcomes in terms of mortality and complication rates. For further evaluation, larger patient numbers are necessary to demonstrate statistical significance for the different surgical techniques. Results of zone 2 patients were significantly better compared to those of zone 3 patients. However, it must be taken into consideration that our FET technique was developed, improved and simplified from the experience we gained from the zone 3 cases. CONCLUSION Although the FET procedure remains a major surgery for treatment of extensive thoracic aortic diseases, the complexity and invasiveness of the procedure can be significantly reduced by stent graft deployment in aortic arch zone 2 combined with an extra-anatomic bypass to the distal LSA via a supraclavicular access during reperfusion. Simplifying and standardizing the FET procedure led to shorter HCA and SACP times and was therefore associated with significantly improved early outcomes. This makes the FET procedure safe, reproducible and easier to perform. ACKNOWLEDGEMENTS The authors thank Terumo Aortic for providing the Thoraflex™ Hybrid Plexus prosthesis illustration (Fig. 1). Conflict of interest: Christian Detter is a proctor for Terumo Aortic. All other authors declared no conflict of interest. REFERENCES 1 Ma W-G , Zheng J , Sun L-Z , Salamone G , Elefteriades JA. Open stented grafts for frozen elephant trunk technique: technical aspects and current outcomes . Aorta 2015 ; 3 : 122 – 35 . Google Scholar Crossref Search ADS PubMed 2 Tsagakis K , Dohle DS , Wendt D , Wiese W , Benedik J , Lieder H et al. Left subclavian artery rerouting and selective perfusion management in frozen elephant trunk surgery . Minim Invasive Ther Allied Technol 2015 ; 24 : 311 – 16 . Google Scholar PubMed 3 Hickey GL , Dunning J , Seifert B , Sodeck G , Carr MJ , Burger HU et al. Statistical and data reporting guidelines for the European Journal of Cardio-Thoracic Surgery and the Interactive CardioVascular and Thoracic Surgery . Eur J Cardiothorac Surg 2015 ; 48 : 180 – 93 . Google Scholar Crossref Search ADS PubMed 4 Bender R , Lange S. Adjusting for multiple testing—when and how? J Clin Epidemiol 2001 ; 54 : 343 – 9 . Google Scholar Crossref Search ADS PubMed 5 De Paulis R. Towards a better, complete treatment of aortic arch pathologies . Eur J Cardiothorac Surg 2017 ; 51 : i1 – 3 . Google Scholar Crossref Search ADS PubMed 6 Di Bartolomeo R , Murana G , Di Marco L , Alfonsi J , Gliozzi G , Amodio C et al. Is the frozen elephant trunk frozen? Gen Thorac Cardiovasc Surg 2018 ; 67 : 111 – 17 . Google Scholar Crossref Search ADS PubMed 7 Ius F , Fleissner F , Pichlmaier M , Karck M , Martens A , Haverich A et al. Total aortic arch replacement with the frozen elephant trunk technique: 10-year follow-up single-centre experience . Eur J Cardiothorac Surg 2013 ; 44 : 949 – 57 . Google Scholar Crossref Search ADS PubMed 8 Leontyev S , Tsagakis K , Pacini D , Di Bartolomeo R , Mohr FW , Weiss G et al. Impact of clinical factors and surgical techniques on early outcome of patients treated with frozen elephant trunk technique by using EVITA open stent-graft: results of a multicentre study . Eur J Cardiothorac Surg 2016 ; 49 : 660 – 6 . Google Scholar Crossref Search ADS PubMed 9 Shrestha M , Martens A , Kaufeld T , Beckmann E , Bertele S , Krueger H et al. Single-centre experience with the frozen elephant trunk technique in 251 patients over 15 years . Eur J Cardiothorac Surg 2017 ; 52 : 858 – 66 . Google Scholar Crossref Search ADS PubMed 10 Tsagakis K , Dohle D , Benedik J , Lieder H , Jakob H. Overall Essen’s experience with the E-vita open hybrid stent graft system and evolution of the surgical technique . Ann Cardiothorac Surg 2013 ; 2 : 612 – 20 . Google Scholar PubMed 11 Pichlmaier M , Luehr M , Rutkowski S , Fabry T , Guenther S , Hagl C et al. Aortic arch hybrid repair: Stent-Bridging of the Supra-Aortic Vessel Anastomoses (SAVSTEB) . Ann Thorac Surg 2017 ; 104 : e463 – 5 . Google Scholar Crossref Search ADS PubMed 12 Czerny M , Rylski B , Kari FA , Kreibich M , Morlock J , Scheumann J et al. Technical details making aortic arch replacement a safe procedure using the ThoraflexTM Hybrid prosthesis . Eur J Cardiothorac Surg 2017 ; 51 : i15 – 19 . Google Scholar Crossref Search ADS PubMed 13 Katayama K , Uchida N , Katayama A , Takahashi S , Takasaki T , Kurosaki T et al. Multiple factors predict the risk of spinal cord injury after the frozen elephant trunk technique for extended thoracic aortic disease . Eur J Cardiothor Surg 2015 ; 47 : 616 – 20 . Google Scholar Crossref Search ADS 14 Cefarelli M , Murana G , Surace GG , Castrovinci S , Jafrancesco G , Kelder JC et al. Elective aortic arch repair: factors influencing neurologic outcome in 791 patients . Ann Thorac Surg 2017 ; 104 : 2016 – 23 . Google Scholar Crossref Search ADS PubMed 15 Haldenwang PL , Bechtel M , Moustafine V , Buchwald D , Wippermann J , Wahlers T et al. State of the art in neuroprotection during acute type A aortic dissection repair . Perfusion 2012 ; 27 : 119 – 26 . Google Scholar Crossref Search ADS PubMed 16 Tong G , Zhang B , Zhou X , Tao Y , Yan T , Wang X et al. Bilateral versus unilateral antegrade cerebral perfusion in total arch replacement for type A aortic dissection . J Thorac Cardiovasc Surg 2017 ; 154 : 767 – 75 . Google Scholar Crossref Search ADS PubMed 17 De Paulis R , Czerny M , Weltert L , Bavaria J , Borger MA , Carrel TP et al. Current trends in cannulation and neuroprotection during surgery of the aortic arch in Europe . Eur J Cardiothorac Surg 2015 ; 47 : 917 – 23 . Google Scholar Crossref Search ADS PubMed © The Author(s) 2019. 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/open_access/funder_policies/chorus/standard_publication_model)

Journal

European Journal of Cardio-Thoracic Surgery – Oxford University Press

Published: Apr 8, 2019

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