Application of hybrid Stage I palliation for patients with two ventricular cavities and hypoplastic left heart structures

Application of hybrid Stage I palliation for patients with two ventricular cavities and... Abstract OBJECTIVES To assess the feasibility of hybrid Stage I palliation consisting of bilateral pulmonary artery bandings and ductal stenting for patients with 2 ventricular cavities and hypoplastic left heart structures. METHODS Eleven consecutive patients who underwent hybrid Stage I palliation between 2010 and 2017 were enrolled. The diagnoses were interrupted aortic arch/coarctation of the aorta, ventricular septal defect and significant left ventricular (LV) outflow tract obstruction in 5 patients, critical aortic stenosis and reduced LV contraction in 3 patients and hypoplastic left heart complex in 3 patients. RESULTS The median age at definitive surgery was 12 months (range 6–22 months). During the mean follow-up period of 24 months (range 9–83 months) following the definitive surgery, there was 1 death. Two patients with interrupted aortic arch/coarctation of the aorta did not undergo the Yasui operation but underwent arch repair and ventricular septal defect closure after the growth of the aortic valve and LV outflow tract. For 2 of the 3 patients with critical aortic stenosis, biventricular repair was performed. Of the 3 patients with hypoplastic left heart complex, 2 patients showed growth of the mitral valve and left ventricle following LV rehabilitation by balloon pulmonary artery dilatation or surgical debanding of the banded pulmonary arteries and subsequently underwent biventricular repair, which resulted in 1 death. CONCLUSIONS Hybrid Stage I palliation would be a safe and beneficial treatment for patients with 2 ventricles, as a bridge to decide whether and how to achieve a biventricular repair and whether it should be preceded by a preliminary LV rehabilitation. Hybrid Stage 1 palliation, Biventricular repair, Left ventricular rehabilitation, Hypoplastic left heart INTRODUCTION In addition to revealing late clinical features of the Fontan circulation, the importance of biventricular repair (BVR) is increasing. Although technically complex BVR for neonates with hypoplastic left heart structures may be possible [1–4], the decision for an appropriate procedure is not easy, because the evaluation of size and function of left heart structures is sometimes inaccurate during the early neonatal period. In addition, the growth potential of borderline-sized left heart structures usually cannot be confirmed soon after birth. It is also unclear whether subsequent rehabilitation promotes their growth sufficiently to obtain biventricular circulation [5, 6]. Hybrid Stage I palliation (HS1P), consisting of bilateral pulmonary artery bandings and ductal stenting with or without balloon atrial septectomy or intra-atrial stenting, was developed as an alternative to the Norwood procedure for high-risk patients with hypoplastic left heart syndrome [7]. Since 2010, we have used this strategy for patients with 2 ventricular cavities to determine the necessity for BVR, to determine BVR procedures or to facilitate BVR following a preliminary left ventricular (LV) rehabilitation. In this study, we reviewed our institutional experience with HS1P for patients with 2 ventricular cavities and hypoplastic left heart structures. MATERIALS AND METHODS Patients The National Cerebral and Cardiovascular Center Institutional Review Board approved this retrospective study and waived the need for obtaining patient consent. Since 2010, 11 patients with 2 ventricular cavities and hypoplastic left heart structures underwent HS1P (Table 1). The main diagnoses were interrupted aortic arch/coarctation of the aorta complex (n = 5) with LV outflow tract obstruction (n= 4) or respiratory failure (n= 1), critical aortic stenosis with reduced LV function (n = 3) and hypoplastic left heart complex (n = 3). The median gestational age and birthweight were 38 weeks (range 34–40 weeks) and 2.7 kg (range 1.4–3.1 kg), respectively. Of the 11 patients, 1 (9.1%) patient was a preterm delivery. There were 5 low-birthweight infants (45.4%). A chromosomal abnormality was detected in 4 (36.4%) patients; of these patients, 2 patients had 22q11.2 deletion syndrome, 1 patient had 5p deletion syndrome and 1 had partial trisomy 8. Table 1: Patient characteristics Number of patients (n) 11 Male: female (n) 7:4 Diagnosis (n)  IAA/CoA complex with LVOTO 5  HLHC 3  cAS with reduced LV contraction 3 Gestational age (weeks), median (range) 38 (34–40)  <37 weeks (n) 1 Birthweight (kg), median (range) 2.6 (1.4–3.1)  <2.5 kg (n) 5 Body surface area at birth (m2), median (range) 0.18 (0.12–0.2) Chromosomal abnormality (n) 4 Age at bPAB (days), median (range) 7 (3–50) Age at DS (days), median (range) 24 (5–78) Number of patients (n) 11 Male: female (n) 7:4 Diagnosis (n)  IAA/CoA complex with LVOTO 5  HLHC 3  cAS with reduced LV contraction 3 Gestational age (weeks), median (range) 38 (34–40)  <37 weeks (n) 1 Birthweight (kg), median (range) 2.6 (1.4–3.1)  <2.5 kg (n) 5 Body surface area at birth (m2), median (range) 0.18 (0.12–0.2) Chromosomal abnormality (n) 4 Age at bPAB (days), median (range) 7 (3–50) Age at DS (days), median (range) 24 (5–78) bPAB: bilateral pulmonary artery bandings; cAS: critical aortic stenosis; CoA: coarctation of aorta; DS: ductal stenting; HLHC: hypoplastic left heart complex; IAA: interrupted aortic arch; LV: left ventricle; LVOTO: left ventricular outflow tract obstruction. Table 1: Patient characteristics Number of patients (n) 11 Male: female (n) 7:4 Diagnosis (n)  IAA/CoA complex with LVOTO 5  HLHC 3  cAS with reduced LV contraction 3 Gestational age (weeks), median (range) 38 (34–40)  <37 weeks (n) 1 Birthweight (kg), median (range) 2.6 (1.4–3.1)  <2.5 kg (n) 5 Body surface area at birth (m2), median (range) 0.18 (0.12–0.2) Chromosomal abnormality (n) 4 Age at bPAB (days), median (range) 7 (3–50) Age at DS (days), median (range) 24 (5–78) Number of patients (n) 11 Male: female (n) 7:4 Diagnosis (n)  IAA/CoA complex with LVOTO 5  HLHC 3  cAS with reduced LV contraction 3 Gestational age (weeks), median (range) 38 (34–40)  <37 weeks (n) 1 Birthweight (kg), median (range) 2.6 (1.4–3.1)  <2.5 kg (n) 5 Body surface area at birth (m2), median (range) 0.18 (0.12–0.2) Chromosomal abnormality (n) 4 Age at bPAB (days), median (range) 7 (3–50) Age at DS (days), median (range) 24 (5–78) bPAB: bilateral pulmonary artery bandings; cAS: critical aortic stenosis; CoA: coarctation of aorta; DS: ductal stenting; HLHC: hypoplastic left heart complex; IAA: interrupted aortic arch; LV: left ventricle; LVOTO: left ventricular outflow tract obstruction. Procedure of hybrid stage I palliation Because of the lack of a hybrid operating theatre and the interventional cardiologist’s preference, HS1P was not performed as a single procedure. Bilateral pulmonary artery bandings were performed following ductal stenting in all patients, except 1 patient who developed ductal shock prior to his arrival via median full sternotomy, at a median age of 7 days (range 3–50 days). After careful dissection, the branch pulmonary arteries were banded to reduce their inner diameter to <1.5 mm, confirmed by intraoperative direct 2D echocardiography. For patients with hypoplastic left heart complex, banding tape was fixed with absorbable sutures to facilitate later dilation of the banded site by percutaneous balloon pulmonary artery dilation. At 1.5 mm from the inside fixation with an absorbable suture, an additional fixation was placed with a non-absorbable suture to prevent excessive dilatation. Ductal stenting was performed with PALMAZ® GENESIS™ on OPTA™ Pro (Cordis, Cardinal Health Inc., Fremont, CA, USA) at the median age of 27 days (range 5–78 days) and was approached via the femoral vein. The size of the implanted stent was 6 mm in 6 patients and 8 mm in 5 patients; the length of the stent was 15 mm in 4 patients, 18 mm in 6 patients and 24 mm in 1 patient. No patient required redilatation of the implanted stent, but additional stent implantation was needed in 1 patient for in-stent stenosis. Indication of hybrid Stage I palliation and institutional criteria for biventricular repair and its procedures Patients with interrupted aortic arch/coarctation of the aorta complex should have 2 balanced ventricles; therefore, the aim of HS1P was to provide alternative BVR procedures. Selection of the BVR procedure was based on the size of the aortic valve diameter and LV outflow tract diameter in systole, estimated by a parasternal long-axis view of transthoracic 2D echocardiography. When the z-value of the aortic valve diameter was less than −3, the Yasui operation was selected. If the z-value of the aortic valve diameter was greater than −3, but the LV outflow tract diameter was less than −3, LV outflow tract myectomy and the closure of ventricular septal defect (VSD) were selected. For patients with critical aortic stenosis and reduced LV function associated with endocardial fibroelastosis, HS1P and subsequent balloon aortic valvotomy were performed to confirm the recovery of both LV systolic and diastolic function, as previously reported [8]. For patients with hypoplastic left heart complex, subsequent LV rehabilitation following HS1P by balloon pulmonary artery dilatation at banded sites or surgical debanding was performed to gradually increase the LV volume preload. Notably, the term ‘LV rehabilitation’ is different from its original meaning, as previously reported [9]. HS1P with subsequent LV rehabilitation indicated for patients with z-values of LV end-diastolic diameter greater than −5, and z-values of mitral valve diameter greater than −4, was estimated with the apical 4-chamber view of 2D transthoracic echocardiography. During rehabilitation, small atrial communication (∼3 mm) was maintained by balloon atrial septostomy. After LV rehabilitation, BVR was indicated, if the z-value of LV end-diastolic diameter was above 0. Management of ductal stent and bilateral pulmonary artery during definitive surgery During definitive surgery, ductal stenting was completely removed under hypothermic (18°C) lower body circulatory arrest with selective cerebral perfusion. After removal of the banding tapes, branch pulmonary arteries were dilated from inside with a Hegar dilator in 4 patients, augmented by an autopericardial patch in 5 patients or expanded polytetrafluoroethylene in 1 patient. Selection of the repair method mainly depended on the time between HS1P and definitive surgery. Study method This study was a retrospective, single-institutional study. From electronic clinical records, operative records, echocardiography and cardiac catheterization reports and outpatient clinical records, the following variables were evaluated: (i) overall outcomes, (ii) individual clinical courses after HS1P based on main diagnoses and (iii) complications following definitive surgeries. Data were analysed using JMP® 11 (SAS Institute Inc., Cary, NC, USA). During the study period, heart transplantation or LV assist device implantation were not indicated for patients with post-cardiotomy heart failure in Japan. RESULTS Overall outcomes All patients underwent definitive surgery, except 1 patient with hypoplastic left heart complex, and the median follow-up period from definitive surgery was 22 months (range 4–45 months). The median age, body weight and body surface area at definitive surgery were 12 months (range 6–34 months), 6.0 kg (range 5.2–11.4 kg) and 0.31 m2 (range 0.28–0.51 m2), respectively (Table 2). The median duration between HS1P and definitive surgery was 11.6 months (range 4.8–21.6 months). The actual survival rate at 3 years following the definitive surgery was 90%. There was 1 in-hospital mortality, and no late mortalities. Table 2: Late complications following definitive surgeries (n = 9) Variables n (%) Complications  LVOTO required reoperation 0  Recurrent CoA 0  Bronchial stenosis 0  Pacemaker implantation 0 Surgical intervention  CRT implantation 1 (11)  MVR + re-RVOTR 1 (11)  Re-RVOTR 1 (11) Catheter intervention  PTA for branch pulmonary artery 4 (44)  Ablation for atrial tachyarrhythmia 1 (11) Variables n (%) Complications  LVOTO required reoperation 0  Recurrent CoA 0  Bronchial stenosis 0  Pacemaker implantation 0 Surgical intervention  CRT implantation 1 (11)  MVR + re-RVOTR 1 (11)  Re-RVOTR 1 (11) Catheter intervention  PTA for branch pulmonary artery 4 (44)  Ablation for atrial tachyarrhythmia 1 (11) CoA: coarctation of aorta; CRT: cardiac resynchronization therapy; LVOTO: left ventricular outflow tract obstruction; MVR: mitral valve replacement; PTA: percutaneous transluminal angioplasty; RVOTR: right ventricular outflow tract obstruction. Table 2: Late complications following definitive surgeries (n = 9) Variables n (%) Complications  LVOTO required reoperation 0  Recurrent CoA 0  Bronchial stenosis 0  Pacemaker implantation 0 Surgical intervention  CRT implantation 1 (11)  MVR + re-RVOTR 1 (11)  Re-RVOTR 1 (11) Catheter intervention  PTA for branch pulmonary artery 4 (44)  Ablation for atrial tachyarrhythmia 1 (11) Variables n (%) Complications  LVOTO required reoperation 0  Recurrent CoA 0  Bronchial stenosis 0  Pacemaker implantation 0 Surgical intervention  CRT implantation 1 (11)  MVR + re-RVOTR 1 (11)  Re-RVOTR 1 (11) Catheter intervention  PTA for branch pulmonary artery 4 (44)  Ablation for atrial tachyarrhythmia 1 (11) CoA: coarctation of aorta; CRT: cardiac resynchronization therapy; LVOTO: left ventricular outflow tract obstruction; MVR: mitral valve replacement; PTA: percutaneous transluminal angioplasty; RVOTR: right ventricular outflow tract obstruction. Individual clinical courses by main diagnosis Interrupted aortic arch/coarctation of the aorta complex One patient who was not premature but experienced respiratory failure soon after birth (later diagnosed as congenital central hypoventilation syndrome) was free from LV outflow tract obstruction before and after HS1P and underwent arch repair and VSD closure as the definitive surgery (Fig. 1A). Of the remaining 4 patients with LV outflow tract obstruction, growth of the LV outflow tract and aortic valve was confirmed in 2 patients (Fig. 2), 1 patient underwent arch repair and VSD closure, and 1 patient underwent arch repair, VSD closure and LV outflow tract myectomy. Figure 1: View largeDownload slide Individual clinical courses following hybrid Stage 1 palliation by main diagnosis. (A) IAA or CoA complex, (B) cAS and (C) HLHC. AVP: aortic valve plasty; BAS: balloon atrial septostomy; BDG: bidirectional Glenn; BVR: biventricular repair; cAS: critical aortic stenosis; CoA: coarctation of aorta; HLHC: hypoplastic left heart complex; IAA: interrupted aortic arch; MVP: mitral valve plasty; OAC: open aortic commissurotomy; PA: pulmonary artery; PTAV: percutaneous transluminal aortic valvotomy; PTBD: percutaneous balloon dilation at the banded site; SAS: subaortic stenosis; SV: single ventricle; VSD: ventricular septal defect. Figure 1: View largeDownload slide Individual clinical courses following hybrid Stage 1 palliation by main diagnosis. (A) IAA or CoA complex, (B) cAS and (C) HLHC. AVP: aortic valve plasty; BAS: balloon atrial septostomy; BDG: bidirectional Glenn; BVR: biventricular repair; cAS: critical aortic stenosis; CoA: coarctation of aorta; HLHC: hypoplastic left heart complex; IAA: interrupted aortic arch; MVP: mitral valve plasty; OAC: open aortic commissurotomy; PA: pulmonary artery; PTAV: percutaneous transluminal aortic valvotomy; PTBD: percutaneous balloon dilation at the banded site; SAS: subaortic stenosis; SV: single ventricle; VSD: ventricular septal defect. Figure 2: View largeDownload slide Changes of AVD and LVOTD in patients with interrupted aortic arch or coarctation of the aorta and VSD after hybrid Stage 1 palliation. AVD: aortic valve diameter; LVOTD: left ventricular outflow tract diameter; VSD: ventricular septal defect. Figure 2: View largeDownload slide Changes of AVD and LVOTD in patients with interrupted aortic arch or coarctation of the aorta and VSD after hybrid Stage 1 palliation. AVD: aortic valve diameter; LVOTD: left ventricular outflow tract diameter; VSD: ventricular septal defect. Definitive surgery was performed at the median weight of 6 kg (5.5–7.2 kg) and the median age of 17 months (5–20 months), and no patient showed significant lower body cyanosis prior to the operation. However, 1 patient who awaited definitive surgery until 20 months developed left bronchial stenosis due to compression by the ductal stent. Instead of direct anastomosis, the aortic arch of the patient was reconstructed with interposition of glutaraldehyde-treated autopericardial roll during the definitive surgery, and relief of left bronchial stenosis was confirmed 1 month later by computed tomography. Critical aortic stenosis with reduced left ventricular function As mentioned earlier, the clinical courses of 2 of the 3 patients has already been described in our previous report [8]. For the third patient, who was born with a body weight of 1.8 kg and associated with aortic arch obstruction, LV systolic function smoothly recovered following HS1P and subsequent balloon aortic valvotomy, and thus a Ross operation was scheduled (Fig. 1B). However, a further careful estimation of the aortic valve detected a still fused commissure, and nodule-like thickness of the leaflets restricted their mobility; so BVR, which consisted of aortic arch reconstruction, aortic valve commissurotomy and leaflet slicing, was successfully performed at 10 months. At the time of BVR, the development of secondary left pulmonary vein stenosis was also relieved with a primary sutureless technique. At the last follow-up, the pressure gradient across the aortic valve was 19 mmHg, and regurgitation was trivial. Hypoplastic left heart complex One of the 3 patients developed significant pulmonary hypertension and severe hypoxia during the first balloon pulmonary artery dilatation (Fig. 1C). Then, balloon atrial septostomy was concomitantly performed, which meant BVR was no longer indicated. A Norwood operation concomitant with bidirectional Glenn anastomosis was scheduled. Two patients showed sufficient growth of the LV end-diastolic diameter (Fig. 3). Chronological changes of the LV end-diastolic diameter, mitral valve diameter and pulmonary vascular resistance of the first patient are shown in Fig. 4. At the age of 12 months, arch repair, VSD closure and papillary muscle splitting for the parachute-like mitral valve were successfully performed. The second patient was complicated by high LV end-diastolic pressure and high pulmonary vascular resistance during the LV rehabilitation. BVR was performed at the age of 6 months (Fig. 5). This was followed by a redo surgery consisting of mitral valve replacement for iatrogenic significant regurgitation and relief of previously underestimated valvular and supravalvular aortic stenosis 1.5 months later. However, low cardiac output syndrome and pulmonary hypertension continued after that. Although single ventricular conversion was attempted at 4 months after the BVR, low cardiac output syndrome and cyanosis became critical. Figure 3: View largeDownload slide Changes of LVEDD and MVD in patients with hypoplastic left heart complex after hybrid Stage 1 palliation. BVR: biventricular repair; LVEDD: left ventricular end-diastolic diameter; MVD: mitral valve diameter; SV: single ventricle; SVR: single ventricle repair. Figure 3: View largeDownload slide Changes of LVEDD and MVD in patients with hypoplastic left heart complex after hybrid Stage 1 palliation. BVR: biventricular repair; LVEDD: left ventricular end-diastolic diameter; MVD: mitral valve diameter; SV: single ventricle; SVR: single ventricle repair. Figure 4: View largeDownload slide Apical 4-chamber view (A) before and (B) after HS1P and (C) chronological changes of z-values of MVD and LVEDD and PVR in 1 patient in the hypoplastic left heart complex group. BVR: biventricular repair; HS1P: hybrid Stage I palliation; LV: left ventricle; LVEDD: left ventricular end-diastolic diameter; MVD: mitral valve diameter; PTBD: percutaneous balloon dilation at the banded site; PVR: pulmonary vascular resistance; RV: right ventricle. Figure 4: View largeDownload slide Apical 4-chamber view (A) before and (B) after HS1P and (C) chronological changes of z-values of MVD and LVEDD and PVR in 1 patient in the hypoplastic left heart complex group. BVR: biventricular repair; HS1P: hybrid Stage I palliation; LV: left ventricle; LVEDD: left ventricular end-diastolic diameter; MVD: mitral valve diameter; PTBD: percutaneous balloon dilation at the banded site; PVR: pulmonary vascular resistance; RV: right ventricle. Figure 5: View largeDownload slide Apical 4-chamber view and parasternal short-axis view (A) before and (B) after HS1P and (C) chronological changes of z-values of MVD and LVEDD PVR and LVEDP after HS1P in 2 patients in the hypoplastic left heart complex group. BVR: biventricular repair; HS1P: hybrid Stage I palliation; LV: left ventricle; LVEDD: left ventricular end-diastolic diameter; LVEDP: left ventricular end-diastolic pressure; MVD: mitral valve diameter; PVR: pulmonary vascular resistance; PTBD: percutaneous balloon dilation at banded site; RV: right ventricle. Figure 5: View largeDownload slide Apical 4-chamber view and parasternal short-axis view (A) before and (B) after HS1P and (C) chronological changes of z-values of MVD and LVEDD PVR and LVEDP after HS1P in 2 patients in the hypoplastic left heart complex group. BVR: biventricular repair; HS1P: hybrid Stage I palliation; LV: left ventricle; LVEDD: left ventricular end-diastolic diameter; LVEDP: left ventricular end-diastolic pressure; MVD: mitral valve diameter; PVR: pulmonary vascular resistance; PTBD: percutaneous balloon dilation at banded site; RV: right ventricle. Late complications after definitive surgeries Recurrent LV outflow tract obstruction, aortic arch obstruction, bronchial stenosis or pacemaker implantation were not observed during the entire follow-up period (Table 2). The rate of freedom from reoperation at 3 years after definitive surgeries was 75%. A total of 3 surgical interventions were required in 2 patients (Table 2). Patients with critical aortic stenosis who had undergone a Ross–Konno operation developed heart failure due to ventricular dys-synchrony originating from complete left bundle branch block; hence, cardiac resynchronization therapy had been introduced since 1 year after discharge. After that, mitral regurgitation progressed, and mitral valve replacement and redo right ventricle-to-pulmonary artery conduit replacement were concomitantly performed 3 years later. The other patient who had undergone the Yasui operation required a redo right ventricle-to-pulmonary artery conduit replacement. As for the catheter-based interventions, balloon pulmonary artery dilatation was performed for postoperative branch pulmonary stenosis in 4 of the 9 (44%) patients. One patient with hypoplastic left heart complex who had undergone BVR developed atrial tachycardia, and so catheter ablation was repeated. DISCUSSION This study reviewed mid-term clinical outcomes of HS1P for patients with hypoplastic left heart structures and 2 ventricular cavities. HS1P contributed to the appropriate selection of BVR procedure, choice of candidate for BVR and growth of left heart structures sufficient to go on to BVR, but resulted in 1 in-hospital mortality for a patient who underwent BVR following LV rehabilitation. There are several surgical options to enlarge hypoplastic aortic valves and LV outflow tracts, such as the surgical aortic valvuloplasty, Ross–Konno ventriculoplasty or Yasui operation (Norwood/Rastelli procedure) if VSD exists [10]. However, these surgeries are technically complex, especially during the neonatal period, and so reoperation is inevitable. For patients with interrupted aortic arch or coarctation of the aorta complex, growth of the aortic valve after bilateral pulmonary artery banding with keeping prostaglandin E1 administration had been previously reported [11]. It showed that 1-month interval was believed to be sufficient to decide the type of definitive surgical procedure. Also, recovery of the LV function could be confirmed within 1 year after balloon aortic valvotomy [12]. Based on these findings, we may decide on the definitive surgery so late that several complications, such as bronchial stenosis and pulmonary veins obstruction, occurred during the inter-stage period. Moreover, reconstruction of banded branch pulmonary arteries is difficult long after bilateral pulmonary artery bandings. Now, we believe that less than 6 months after HS1P is the suitable timing to perform definitive surgery. On the contrary, effective options to enlarge LV inflow and the cavity itself are scarce [9]; therefore, the process of LV rehabilitation is never too long if sufficient growth is obtained. Indeed, responses to the LV rehabilitation and clinical outcomes were quite different in our 3 study cohorts. As mentioned earlier, the second patient could not tolerate BVR; nevertheless growth of the left ventricle seemed to be sufficient to proceed. Although insufficient surgical relief of both LV inflow and outflow obstructions must have been a serious matter, significant pulmonary hypertension and high left atrial pressure under the presence of tiny atrial communication had been noted just prior to BVR procedure. The previous report showed that 1 of the 2 patients who undergone coarctation repair and immediately developed significant backwards pulmonary hypertension derived from hypoplastic left heart structures could proceed a BVR 3 months after a palliative Van Praagh shunt [13] combined with bilateral pulmonary artery bandings [14]. From this, we realize that BVR should have been postponed until the normalization of elevated ventricular end-diastolic pressure was confirmed, otherwise BVR would have not been indicated when significant backwards pulmonary hypertension remained. A previous report already showed that the application of HS1P allowed 36 of 40 patients with hypoplastic left heart complex to achieve BVR [15] ‘without’ subsequent LV rehabilitation, but all cohorts had relatively large-sized mitral valve prior to HS1P (z-value of more than −2.97), and its growth was statistically significant but limited (before HS1P vs at BVR, P = 0.05). The other report showed that growth of the hypoplastic mitral valve (but z-value of more than −3.7) was normalized after the relief of left-sided obstructive lesions [16]. From these findings and our experiences, LV rehabilitation may be recommended for patients with z-values greater than −4 for the mitral valve diameter and a LV end-diastolic diameter greater than −5. However, further accumulation of experiences is mandatory to reveal suitable candidates who should undergo HS1P and LV rehabilitation, instead of neonatal single-ventricle palliation. Limitations This study is not a comparative study between the HS1P and the neonatal primary repair, and the number of patients is limited. So far, this is not an overview investigation but a series of case reports. Further accumulation of experiences is required, and randomization should be conducted to reveal the superiority of the presented surgical strategy. CONCLUSIONS In summary, HS1P would be a safe and beneficial palliation as a bridge to a decision for the indication of BVR in patients with 2 ventricular cavities and hypoplastic left heart structures, to a decision regarding BVR procedure or to a bridge to BVR following subsequent LV rehabilitation. Further accumulation of experiences is mandatory to reveal suitable candidates to undergo HS1P and LV rehabilitation, instead of neonatal single-ventricle palliation. Conflict of interest: none declared. REFERENCES 1 Tchervenkov CI , Tahta SA , Jutras LC , Belan MJ. Biventricular repair in neonates with hypoplastic left heart complex . Ann Thorac Surg 1998 ; 66 : 1350 – 7 . Google Scholar CrossRef Search ADS PubMed 2 Hoashi T , Bove EL , Devaney EJ , Hirsch JC , Ohye RG. Intermediate-term clinical outcomes of primary biventricular repair for left ventricular outflow tract obstruction and ventricular septal defect . J Thorac Cardiovasc Surg 2011 ; 141 : 200 – 6 . Google Scholar CrossRef Search ADS PubMed 3 Serraf A , Piot JD , Bonnet N , Lacour-Gayet F , Touchot A , Bruniaux J et al. . Biventricular repair approach in ducto-dependent neonates with hypoplastic but morphologically normal left ventricle . J Am Coll Cardiol 1999 ; 33 : 827 – 34 . Google Scholar CrossRef Search ADS PubMed 4 Tani LY , Minich LL , Pagotto LT , Shaddy RE , McGough EC , Hawkins JA. Left heart hypoplasia and neonatal aortic arch obstruction: is the Rhodes left ventricular adequacy score applicable? J Thorac Cardiovasc Surg 1999 ; 118 : 81 – 6 . 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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

Application of hybrid Stage I palliation for patients with two ventricular cavities and hypoplastic left heart structures

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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 To assess the feasibility of hybrid Stage I palliation consisting of bilateral pulmonary artery bandings and ductal stenting for patients with 2 ventricular cavities and hypoplastic left heart structures. METHODS Eleven consecutive patients who underwent hybrid Stage I palliation between 2010 and 2017 were enrolled. The diagnoses were interrupted aortic arch/coarctation of the aorta, ventricular septal defect and significant left ventricular (LV) outflow tract obstruction in 5 patients, critical aortic stenosis and reduced LV contraction in 3 patients and hypoplastic left heart complex in 3 patients. RESULTS The median age at definitive surgery was 12 months (range 6–22 months). During the mean follow-up period of 24 months (range 9–83 months) following the definitive surgery, there was 1 death. Two patients with interrupted aortic arch/coarctation of the aorta did not undergo the Yasui operation but underwent arch repair and ventricular septal defect closure after the growth of the aortic valve and LV outflow tract. For 2 of the 3 patients with critical aortic stenosis, biventricular repair was performed. Of the 3 patients with hypoplastic left heart complex, 2 patients showed growth of the mitral valve and left ventricle following LV rehabilitation by balloon pulmonary artery dilatation or surgical debanding of the banded pulmonary arteries and subsequently underwent biventricular repair, which resulted in 1 death. CONCLUSIONS Hybrid Stage I palliation would be a safe and beneficial treatment for patients with 2 ventricles, as a bridge to decide whether and how to achieve a biventricular repair and whether it should be preceded by a preliminary LV rehabilitation. Hybrid Stage 1 palliation, Biventricular repair, Left ventricular rehabilitation, Hypoplastic left heart INTRODUCTION In addition to revealing late clinical features of the Fontan circulation, the importance of biventricular repair (BVR) is increasing. Although technically complex BVR for neonates with hypoplastic left heart structures may be possible [1–4], the decision for an appropriate procedure is not easy, because the evaluation of size and function of left heart structures is sometimes inaccurate during the early neonatal period. In addition, the growth potential of borderline-sized left heart structures usually cannot be confirmed soon after birth. It is also unclear whether subsequent rehabilitation promotes their growth sufficiently to obtain biventricular circulation [5, 6]. Hybrid Stage I palliation (HS1P), consisting of bilateral pulmonary artery bandings and ductal stenting with or without balloon atrial septectomy or intra-atrial stenting, was developed as an alternative to the Norwood procedure for high-risk patients with hypoplastic left heart syndrome [7]. Since 2010, we have used this strategy for patients with 2 ventricular cavities to determine the necessity for BVR, to determine BVR procedures or to facilitate BVR following a preliminary left ventricular (LV) rehabilitation. In this study, we reviewed our institutional experience with HS1P for patients with 2 ventricular cavities and hypoplastic left heart structures. MATERIALS AND METHODS Patients The National Cerebral and Cardiovascular Center Institutional Review Board approved this retrospective study and waived the need for obtaining patient consent. Since 2010, 11 patients with 2 ventricular cavities and hypoplastic left heart structures underwent HS1P (Table 1). The main diagnoses were interrupted aortic arch/coarctation of the aorta complex (n = 5) with LV outflow tract obstruction (n= 4) or respiratory failure (n= 1), critical aortic stenosis with reduced LV function (n = 3) and hypoplastic left heart complex (n = 3). The median gestational age and birthweight were 38 weeks (range 34–40 weeks) and 2.7 kg (range 1.4–3.1 kg), respectively. Of the 11 patients, 1 (9.1%) patient was a preterm delivery. There were 5 low-birthweight infants (45.4%). A chromosomal abnormality was detected in 4 (36.4%) patients; of these patients, 2 patients had 22q11.2 deletion syndrome, 1 patient had 5p deletion syndrome and 1 had partial trisomy 8. Table 1: Patient characteristics Number of patients (n) 11 Male: female (n) 7:4 Diagnosis (n)  IAA/CoA complex with LVOTO 5  HLHC 3  cAS with reduced LV contraction 3 Gestational age (weeks), median (range) 38 (34–40)  <37 weeks (n) 1 Birthweight (kg), median (range) 2.6 (1.4–3.1)  <2.5 kg (n) 5 Body surface area at birth (m2), median (range) 0.18 (0.12–0.2) Chromosomal abnormality (n) 4 Age at bPAB (days), median (range) 7 (3–50) Age at DS (days), median (range) 24 (5–78) Number of patients (n) 11 Male: female (n) 7:4 Diagnosis (n)  IAA/CoA complex with LVOTO 5  HLHC 3  cAS with reduced LV contraction 3 Gestational age (weeks), median (range) 38 (34–40)  <37 weeks (n) 1 Birthweight (kg), median (range) 2.6 (1.4–3.1)  <2.5 kg (n) 5 Body surface area at birth (m2), median (range) 0.18 (0.12–0.2) Chromosomal abnormality (n) 4 Age at bPAB (days), median (range) 7 (3–50) Age at DS (days), median (range) 24 (5–78) bPAB: bilateral pulmonary artery bandings; cAS: critical aortic stenosis; CoA: coarctation of aorta; DS: ductal stenting; HLHC: hypoplastic left heart complex; IAA: interrupted aortic arch; LV: left ventricle; LVOTO: left ventricular outflow tract obstruction. Table 1: Patient characteristics Number of patients (n) 11 Male: female (n) 7:4 Diagnosis (n)  IAA/CoA complex with LVOTO 5  HLHC 3  cAS with reduced LV contraction 3 Gestational age (weeks), median (range) 38 (34–40)  <37 weeks (n) 1 Birthweight (kg), median (range) 2.6 (1.4–3.1)  <2.5 kg (n) 5 Body surface area at birth (m2), median (range) 0.18 (0.12–0.2) Chromosomal abnormality (n) 4 Age at bPAB (days), median (range) 7 (3–50) Age at DS (days), median (range) 24 (5–78) Number of patients (n) 11 Male: female (n) 7:4 Diagnosis (n)  IAA/CoA complex with LVOTO 5  HLHC 3  cAS with reduced LV contraction 3 Gestational age (weeks), median (range) 38 (34–40)  <37 weeks (n) 1 Birthweight (kg), median (range) 2.6 (1.4–3.1)  <2.5 kg (n) 5 Body surface area at birth (m2), median (range) 0.18 (0.12–0.2) Chromosomal abnormality (n) 4 Age at bPAB (days), median (range) 7 (3–50) Age at DS (days), median (range) 24 (5–78) bPAB: bilateral pulmonary artery bandings; cAS: critical aortic stenosis; CoA: coarctation of aorta; DS: ductal stenting; HLHC: hypoplastic left heart complex; IAA: interrupted aortic arch; LV: left ventricle; LVOTO: left ventricular outflow tract obstruction. Procedure of hybrid stage I palliation Because of the lack of a hybrid operating theatre and the interventional cardiologist’s preference, HS1P was not performed as a single procedure. Bilateral pulmonary artery bandings were performed following ductal stenting in all patients, except 1 patient who developed ductal shock prior to his arrival via median full sternotomy, at a median age of 7 days (range 3–50 days). After careful dissection, the branch pulmonary arteries were banded to reduce their inner diameter to <1.5 mm, confirmed by intraoperative direct 2D echocardiography. For patients with hypoplastic left heart complex, banding tape was fixed with absorbable sutures to facilitate later dilation of the banded site by percutaneous balloon pulmonary artery dilation. At 1.5 mm from the inside fixation with an absorbable suture, an additional fixation was placed with a non-absorbable suture to prevent excessive dilatation. Ductal stenting was performed with PALMAZ® GENESIS™ on OPTA™ Pro (Cordis, Cardinal Health Inc., Fremont, CA, USA) at the median age of 27 days (range 5–78 days) and was approached via the femoral vein. The size of the implanted stent was 6 mm in 6 patients and 8 mm in 5 patients; the length of the stent was 15 mm in 4 patients, 18 mm in 6 patients and 24 mm in 1 patient. No patient required redilatation of the implanted stent, but additional stent implantation was needed in 1 patient for in-stent stenosis. Indication of hybrid Stage I palliation and institutional criteria for biventricular repair and its procedures Patients with interrupted aortic arch/coarctation of the aorta complex should have 2 balanced ventricles; therefore, the aim of HS1P was to provide alternative BVR procedures. Selection of the BVR procedure was based on the size of the aortic valve diameter and LV outflow tract diameter in systole, estimated by a parasternal long-axis view of transthoracic 2D echocardiography. When the z-value of the aortic valve diameter was less than −3, the Yasui operation was selected. If the z-value of the aortic valve diameter was greater than −3, but the LV outflow tract diameter was less than −3, LV outflow tract myectomy and the closure of ventricular septal defect (VSD) were selected. For patients with critical aortic stenosis and reduced LV function associated with endocardial fibroelastosis, HS1P and subsequent balloon aortic valvotomy were performed to confirm the recovery of both LV systolic and diastolic function, as previously reported [8]. For patients with hypoplastic left heart complex, subsequent LV rehabilitation following HS1P by balloon pulmonary artery dilatation at banded sites or surgical debanding was performed to gradually increase the LV volume preload. Notably, the term ‘LV rehabilitation’ is different from its original meaning, as previously reported [9]. HS1P with subsequent LV rehabilitation indicated for patients with z-values of LV end-diastolic diameter greater than −5, and z-values of mitral valve diameter greater than −4, was estimated with the apical 4-chamber view of 2D transthoracic echocardiography. During rehabilitation, small atrial communication (∼3 mm) was maintained by balloon atrial septostomy. After LV rehabilitation, BVR was indicated, if the z-value of LV end-diastolic diameter was above 0. Management of ductal stent and bilateral pulmonary artery during definitive surgery During definitive surgery, ductal stenting was completely removed under hypothermic (18°C) lower body circulatory arrest with selective cerebral perfusion. After removal of the banding tapes, branch pulmonary arteries were dilated from inside with a Hegar dilator in 4 patients, augmented by an autopericardial patch in 5 patients or expanded polytetrafluoroethylene in 1 patient. Selection of the repair method mainly depended on the time between HS1P and definitive surgery. Study method This study was a retrospective, single-institutional study. From electronic clinical records, operative records, echocardiography and cardiac catheterization reports and outpatient clinical records, the following variables were evaluated: (i) overall outcomes, (ii) individual clinical courses after HS1P based on main diagnoses and (iii) complications following definitive surgeries. Data were analysed using JMP® 11 (SAS Institute Inc., Cary, NC, USA). During the study period, heart transplantation or LV assist device implantation were not indicated for patients with post-cardiotomy heart failure in Japan. RESULTS Overall outcomes All patients underwent definitive surgery, except 1 patient with hypoplastic left heart complex, and the median follow-up period from definitive surgery was 22 months (range 4–45 months). The median age, body weight and body surface area at definitive surgery were 12 months (range 6–34 months), 6.0 kg (range 5.2–11.4 kg) and 0.31 m2 (range 0.28–0.51 m2), respectively (Table 2). The median duration between HS1P and definitive surgery was 11.6 months (range 4.8–21.6 months). The actual survival rate at 3 years following the definitive surgery was 90%. There was 1 in-hospital mortality, and no late mortalities. Table 2: Late complications following definitive surgeries (n = 9) Variables n (%) Complications  LVOTO required reoperation 0  Recurrent CoA 0  Bronchial stenosis 0  Pacemaker implantation 0 Surgical intervention  CRT implantation 1 (11)  MVR + re-RVOTR 1 (11)  Re-RVOTR 1 (11) Catheter intervention  PTA for branch pulmonary artery 4 (44)  Ablation for atrial tachyarrhythmia 1 (11) Variables n (%) Complications  LVOTO required reoperation 0  Recurrent CoA 0  Bronchial stenosis 0  Pacemaker implantation 0 Surgical intervention  CRT implantation 1 (11)  MVR + re-RVOTR 1 (11)  Re-RVOTR 1 (11) Catheter intervention  PTA for branch pulmonary artery 4 (44)  Ablation for atrial tachyarrhythmia 1 (11) CoA: coarctation of aorta; CRT: cardiac resynchronization therapy; LVOTO: left ventricular outflow tract obstruction; MVR: mitral valve replacement; PTA: percutaneous transluminal angioplasty; RVOTR: right ventricular outflow tract obstruction. Table 2: Late complications following definitive surgeries (n = 9) Variables n (%) Complications  LVOTO required reoperation 0  Recurrent CoA 0  Bronchial stenosis 0  Pacemaker implantation 0 Surgical intervention  CRT implantation 1 (11)  MVR + re-RVOTR 1 (11)  Re-RVOTR 1 (11) Catheter intervention  PTA for branch pulmonary artery 4 (44)  Ablation for atrial tachyarrhythmia 1 (11) Variables n (%) Complications  LVOTO required reoperation 0  Recurrent CoA 0  Bronchial stenosis 0  Pacemaker implantation 0 Surgical intervention  CRT implantation 1 (11)  MVR + re-RVOTR 1 (11)  Re-RVOTR 1 (11) Catheter intervention  PTA for branch pulmonary artery 4 (44)  Ablation for atrial tachyarrhythmia 1 (11) CoA: coarctation of aorta; CRT: cardiac resynchronization therapy; LVOTO: left ventricular outflow tract obstruction; MVR: mitral valve replacement; PTA: percutaneous transluminal angioplasty; RVOTR: right ventricular outflow tract obstruction. Individual clinical courses by main diagnosis Interrupted aortic arch/coarctation of the aorta complex One patient who was not premature but experienced respiratory failure soon after birth (later diagnosed as congenital central hypoventilation syndrome) was free from LV outflow tract obstruction before and after HS1P and underwent arch repair and VSD closure as the definitive surgery (Fig. 1A). Of the remaining 4 patients with LV outflow tract obstruction, growth of the LV outflow tract and aortic valve was confirmed in 2 patients (Fig. 2), 1 patient underwent arch repair and VSD closure, and 1 patient underwent arch repair, VSD closure and LV outflow tract myectomy. Figure 1: View largeDownload slide Individual clinical courses following hybrid Stage 1 palliation by main diagnosis. (A) IAA or CoA complex, (B) cAS and (C) HLHC. AVP: aortic valve plasty; BAS: balloon atrial septostomy; BDG: bidirectional Glenn; BVR: biventricular repair; cAS: critical aortic stenosis; CoA: coarctation of aorta; HLHC: hypoplastic left heart complex; IAA: interrupted aortic arch; MVP: mitral valve plasty; OAC: open aortic commissurotomy; PA: pulmonary artery; PTAV: percutaneous transluminal aortic valvotomy; PTBD: percutaneous balloon dilation at the banded site; SAS: subaortic stenosis; SV: single ventricle; VSD: ventricular septal defect. Figure 1: View largeDownload slide Individual clinical courses following hybrid Stage 1 palliation by main diagnosis. (A) IAA or CoA complex, (B) cAS and (C) HLHC. AVP: aortic valve plasty; BAS: balloon atrial septostomy; BDG: bidirectional Glenn; BVR: biventricular repair; cAS: critical aortic stenosis; CoA: coarctation of aorta; HLHC: hypoplastic left heart complex; IAA: interrupted aortic arch; MVP: mitral valve plasty; OAC: open aortic commissurotomy; PA: pulmonary artery; PTAV: percutaneous transluminal aortic valvotomy; PTBD: percutaneous balloon dilation at the banded site; SAS: subaortic stenosis; SV: single ventricle; VSD: ventricular septal defect. Figure 2: View largeDownload slide Changes of AVD and LVOTD in patients with interrupted aortic arch or coarctation of the aorta and VSD after hybrid Stage 1 palliation. AVD: aortic valve diameter; LVOTD: left ventricular outflow tract diameter; VSD: ventricular septal defect. Figure 2: View largeDownload slide Changes of AVD and LVOTD in patients with interrupted aortic arch or coarctation of the aorta and VSD after hybrid Stage 1 palliation. AVD: aortic valve diameter; LVOTD: left ventricular outflow tract diameter; VSD: ventricular septal defect. Definitive surgery was performed at the median weight of 6 kg (5.5–7.2 kg) and the median age of 17 months (5–20 months), and no patient showed significant lower body cyanosis prior to the operation. However, 1 patient who awaited definitive surgery until 20 months developed left bronchial stenosis due to compression by the ductal stent. Instead of direct anastomosis, the aortic arch of the patient was reconstructed with interposition of glutaraldehyde-treated autopericardial roll during the definitive surgery, and relief of left bronchial stenosis was confirmed 1 month later by computed tomography. Critical aortic stenosis with reduced left ventricular function As mentioned earlier, the clinical courses of 2 of the 3 patients has already been described in our previous report [8]. For the third patient, who was born with a body weight of 1.8 kg and associated with aortic arch obstruction, LV systolic function smoothly recovered following HS1P and subsequent balloon aortic valvotomy, and thus a Ross operation was scheduled (Fig. 1B). However, a further careful estimation of the aortic valve detected a still fused commissure, and nodule-like thickness of the leaflets restricted their mobility; so BVR, which consisted of aortic arch reconstruction, aortic valve commissurotomy and leaflet slicing, was successfully performed at 10 months. At the time of BVR, the development of secondary left pulmonary vein stenosis was also relieved with a primary sutureless technique. At the last follow-up, the pressure gradient across the aortic valve was 19 mmHg, and regurgitation was trivial. Hypoplastic left heart complex One of the 3 patients developed significant pulmonary hypertension and severe hypoxia during the first balloon pulmonary artery dilatation (Fig. 1C). Then, balloon atrial septostomy was concomitantly performed, which meant BVR was no longer indicated. A Norwood operation concomitant with bidirectional Glenn anastomosis was scheduled. Two patients showed sufficient growth of the LV end-diastolic diameter (Fig. 3). Chronological changes of the LV end-diastolic diameter, mitral valve diameter and pulmonary vascular resistance of the first patient are shown in Fig. 4. At the age of 12 months, arch repair, VSD closure and papillary muscle splitting for the parachute-like mitral valve were successfully performed. The second patient was complicated by high LV end-diastolic pressure and high pulmonary vascular resistance during the LV rehabilitation. BVR was performed at the age of 6 months (Fig. 5). This was followed by a redo surgery consisting of mitral valve replacement for iatrogenic significant regurgitation and relief of previously underestimated valvular and supravalvular aortic stenosis 1.5 months later. However, low cardiac output syndrome and pulmonary hypertension continued after that. Although single ventricular conversion was attempted at 4 months after the BVR, low cardiac output syndrome and cyanosis became critical. Figure 3: View largeDownload slide Changes of LVEDD and MVD in patients with hypoplastic left heart complex after hybrid Stage 1 palliation. BVR: biventricular repair; LVEDD: left ventricular end-diastolic diameter; MVD: mitral valve diameter; SV: single ventricle; SVR: single ventricle repair. Figure 3: View largeDownload slide Changes of LVEDD and MVD in patients with hypoplastic left heart complex after hybrid Stage 1 palliation. BVR: biventricular repair; LVEDD: left ventricular end-diastolic diameter; MVD: mitral valve diameter; SV: single ventricle; SVR: single ventricle repair. Figure 4: View largeDownload slide Apical 4-chamber view (A) before and (B) after HS1P and (C) chronological changes of z-values of MVD and LVEDD and PVR in 1 patient in the hypoplastic left heart complex group. BVR: biventricular repair; HS1P: hybrid Stage I palliation; LV: left ventricle; LVEDD: left ventricular end-diastolic diameter; MVD: mitral valve diameter; PTBD: percutaneous balloon dilation at the banded site; PVR: pulmonary vascular resistance; RV: right ventricle. Figure 4: View largeDownload slide Apical 4-chamber view (A) before and (B) after HS1P and (C) chronological changes of z-values of MVD and LVEDD and PVR in 1 patient in the hypoplastic left heart complex group. BVR: biventricular repair; HS1P: hybrid Stage I palliation; LV: left ventricle; LVEDD: left ventricular end-diastolic diameter; MVD: mitral valve diameter; PTBD: percutaneous balloon dilation at the banded site; PVR: pulmonary vascular resistance; RV: right ventricle. Figure 5: View largeDownload slide Apical 4-chamber view and parasternal short-axis view (A) before and (B) after HS1P and (C) chronological changes of z-values of MVD and LVEDD PVR and LVEDP after HS1P in 2 patients in the hypoplastic left heart complex group. BVR: biventricular repair; HS1P: hybrid Stage I palliation; LV: left ventricle; LVEDD: left ventricular end-diastolic diameter; LVEDP: left ventricular end-diastolic pressure; MVD: mitral valve diameter; PVR: pulmonary vascular resistance; PTBD: percutaneous balloon dilation at banded site; RV: right ventricle. Figure 5: View largeDownload slide Apical 4-chamber view and parasternal short-axis view (A) before and (B) after HS1P and (C) chronological changes of z-values of MVD and LVEDD PVR and LVEDP after HS1P in 2 patients in the hypoplastic left heart complex group. BVR: biventricular repair; HS1P: hybrid Stage I palliation; LV: left ventricle; LVEDD: left ventricular end-diastolic diameter; LVEDP: left ventricular end-diastolic pressure; MVD: mitral valve diameter; PVR: pulmonary vascular resistance; PTBD: percutaneous balloon dilation at banded site; RV: right ventricle. Late complications after definitive surgeries Recurrent LV outflow tract obstruction, aortic arch obstruction, bronchial stenosis or pacemaker implantation were not observed during the entire follow-up period (Table 2). The rate of freedom from reoperation at 3 years after definitive surgeries was 75%. A total of 3 surgical interventions were required in 2 patients (Table 2). Patients with critical aortic stenosis who had undergone a Ross–Konno operation developed heart failure due to ventricular dys-synchrony originating from complete left bundle branch block; hence, cardiac resynchronization therapy had been introduced since 1 year after discharge. After that, mitral regurgitation progressed, and mitral valve replacement and redo right ventricle-to-pulmonary artery conduit replacement were concomitantly performed 3 years later. The other patient who had undergone the Yasui operation required a redo right ventricle-to-pulmonary artery conduit replacement. As for the catheter-based interventions, balloon pulmonary artery dilatation was performed for postoperative branch pulmonary stenosis in 4 of the 9 (44%) patients. One patient with hypoplastic left heart complex who had undergone BVR developed atrial tachycardia, and so catheter ablation was repeated. DISCUSSION This study reviewed mid-term clinical outcomes of HS1P for patients with hypoplastic left heart structures and 2 ventricular cavities. HS1P contributed to the appropriate selection of BVR procedure, choice of candidate for BVR and growth of left heart structures sufficient to go on to BVR, but resulted in 1 in-hospital mortality for a patient who underwent BVR following LV rehabilitation. There are several surgical options to enlarge hypoplastic aortic valves and LV outflow tracts, such as the surgical aortic valvuloplasty, Ross–Konno ventriculoplasty or Yasui operation (Norwood/Rastelli procedure) if VSD exists [10]. However, these surgeries are technically complex, especially during the neonatal period, and so reoperation is inevitable. For patients with interrupted aortic arch or coarctation of the aorta complex, growth of the aortic valve after bilateral pulmonary artery banding with keeping prostaglandin E1 administration had been previously reported [11]. It showed that 1-month interval was believed to be sufficient to decide the type of definitive surgical procedure. Also, recovery of the LV function could be confirmed within 1 year after balloon aortic valvotomy [12]. Based on these findings, we may decide on the definitive surgery so late that several complications, such as bronchial stenosis and pulmonary veins obstruction, occurred during the inter-stage period. Moreover, reconstruction of banded branch pulmonary arteries is difficult long after bilateral pulmonary artery bandings. Now, we believe that less than 6 months after HS1P is the suitable timing to perform definitive surgery. On the contrary, effective options to enlarge LV inflow and the cavity itself are scarce [9]; therefore, the process of LV rehabilitation is never too long if sufficient growth is obtained. Indeed, responses to the LV rehabilitation and clinical outcomes were quite different in our 3 study cohorts. As mentioned earlier, the second patient could not tolerate BVR; nevertheless growth of the left ventricle seemed to be sufficient to proceed. Although insufficient surgical relief of both LV inflow and outflow obstructions must have been a serious matter, significant pulmonary hypertension and high left atrial pressure under the presence of tiny atrial communication had been noted just prior to BVR procedure. The previous report showed that 1 of the 2 patients who undergone coarctation repair and immediately developed significant backwards pulmonary hypertension derived from hypoplastic left heart structures could proceed a BVR 3 months after a palliative Van Praagh shunt [13] combined with bilateral pulmonary artery bandings [14]. From this, we realize that BVR should have been postponed until the normalization of elevated ventricular end-diastolic pressure was confirmed, otherwise BVR would have not been indicated when significant backwards pulmonary hypertension remained. A previous report already showed that the application of HS1P allowed 36 of 40 patients with hypoplastic left heart complex to achieve BVR [15] ‘without’ subsequent LV rehabilitation, but all cohorts had relatively large-sized mitral valve prior to HS1P (z-value of more than −2.97), and its growth was statistically significant but limited (before HS1P vs at BVR, P = 0.05). The other report showed that growth of the hypoplastic mitral valve (but z-value of more than −3.7) was normalized after the relief of left-sided obstructive lesions [16]. From these findings and our experiences, LV rehabilitation may be recommended for patients with z-values greater than −4 for the mitral valve diameter and a LV end-diastolic diameter greater than −5. However, further accumulation of experiences is mandatory to reveal suitable candidates who should undergo HS1P and LV rehabilitation, instead of neonatal single-ventricle palliation. Limitations This study is not a comparative study between the HS1P and the neonatal primary repair, and the number of patients is limited. So far, this is not an overview investigation but a series of case reports. Further accumulation of experiences is required, and randomization should be conducted to reveal the superiority of the presented surgical strategy. CONCLUSIONS In summary, HS1P would be a safe and beneficial palliation as a bridge to a decision for the indication of BVR in patients with 2 ventricular cavities and hypoplastic left heart structures, to a decision regarding BVR procedure or to a bridge to BVR following subsequent LV rehabilitation. Further accumulation of experiences is mandatory to reveal suitable candidates to undergo HS1P and LV rehabilitation, instead of neonatal single-ventricle palliation. Conflict of interest: none declared. REFERENCES 1 Tchervenkov CI , Tahta SA , Jutras LC , Belan MJ. Biventricular repair in neonates with hypoplastic left heart complex . Ann Thorac Surg 1998 ; 66 : 1350 – 7 . Google Scholar CrossRef Search ADS PubMed 2 Hoashi T , Bove EL , Devaney EJ , Hirsch JC , Ohye RG. Intermediate-term clinical outcomes of primary biventricular repair for left ventricular outflow tract obstruction and ventricular septal defect . J Thorac Cardiovasc Surg 2011 ; 141 : 200 – 6 . Google Scholar CrossRef Search ADS PubMed 3 Serraf A , Piot JD , Bonnet N , Lacour-Gayet F , Touchot A , Bruniaux J et al. . Biventricular repair approach in ducto-dependent neonates with hypoplastic but morphologically normal left ventricle . J Am Coll Cardiol 1999 ; 33 : 827 – 34 . Google Scholar CrossRef Search ADS PubMed 4 Tani LY , Minich LL , Pagotto LT , Shaddy RE , McGough EC , Hawkins JA. Left heart hypoplasia and neonatal aortic arch obstruction: is the Rhodes left ventricular adequacy score applicable? J Thorac Cardiovasc Surg 1999 ; 118 : 81 – 6 . Google Scholar CrossRef Search ADS PubMed 5 Ahmad F , Mangano R , Shore S , Polimenakos A. Critically underdeveloped left heart morphology associated with prematurity and low birth weight: conditional staged rehabilitation towards biventricular repair and time-related growth of left heart structures . Pediatr Cardiol 2017 ; 38 : 1519 – 21 . Google Scholar CrossRef Search ADS PubMed 6 Brown SC , Boshoff D , Eyskens B , Gewillig M. Hybrid approach as bridge to biventricular repair in a neonate with critical aortic stenosis and borderline left ventricle . Eur J Cardiothorac Surg 2009 ; 35 : 1080 – 2 . Google Scholar CrossRef Search ADS PubMed 7 Gibbs JL , Wren C , Watterson KG , Hunter S , Hamilton L. Stenting of the arterial duct combined with banding of the pulmonary arteries and atrial septectomy or septostomy: a new approach to palliation for the hypoplastic left heart syndrome . Br Heart J 1993 ; 69 : 551 – 5 . Google Scholar CrossRef Search ADS PubMed 8 Misumi Y , Hoashi T , Kagisaki K , Yazaki S , Kitano M , Kurosaki K et al. . The importance of hybrid stage 1 palliation for neonates with critical aortic stenosis and reduced left ventricular function . Pediatr Cardiol 2015 ; 36 : 726 – 31 . Google Scholar CrossRef Search ADS PubMed 9 Emani SM , Bacha EA , McElhinney DB , Marx GR , Tworetzky W , Pigula FA et al. . Primary left ventricular rehabilitation is effective in maintaining two-ventricle physiology in the borderline left heart . J Thorac Cardiovasc Surg 2009 ; 138 : 1276 – 82 . Google Scholar CrossRef Search ADS PubMed 10 Hickey EJ , Yeh T Jr , Jacobs JP , Caldarone CA , Tchervenkov CI , McCrindle BW et al. . Ross and Yasui operations for complex biventricular repair in infants with critical left ventricular outflow tract obstruction . Eur J Cardiothorac Surg 2010 ; 37 : 279 – 88 . 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Interact CardioVasc Thorac Surg 2016 ; 23 : 929 – 32 . Google Scholar CrossRef Search ADS PubMed 15 Yerebakan C , Murray J , Valeske K , Thul J , Elmontaser H , Mueller M et al. . Long-term results of biventricular repair after initial Giessen hybrid approach for hypoplastic left heart variants . J Thorac Cardiovasc Surg 2015 ; 149 : 1112 – 20 . Google Scholar CrossRef Search ADS PubMed 16 Avitabile CM , Mercer-Rosa L , Ravishankar C , Rome JJ , Gaynor JW , Spray TL et al. . Experience with biventricular intervention for neonates with mitral valve abnormalities in the setting of critical left-side heart obstruction . Ann Thorac Surg 2015 ; 99 : 877 – 83 . 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: Jan 24, 2018

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