Endocardial Fibroelastosis Resection: When it Works and When it Does Not.

Endocardial fibroelastosis (EFE) is a thickening of the endocardial layer by accumulation of collagen and elastic fibers. Endothelial to mesenchymal transformation is proposed to be the underlying mechanism of formation. Although EFE can occur in both right and left ventricles, this article will focus on management of left ventricular EFE. Through its fibrous, nonelastic manifestation EFE restricts the myocardium leading to diastolic and systolic ventricular dysfunction and prevents ventricular growth in neonates and infants. The presence of EFE may be a marker for underlying myocardial fibrosis as well. The extent of EFE within the left ventricular cavity can be variable ranging from patchy to confluent distribution. Similarly the depth of penetration and degree of infiltration into myocardium can be variable. The management of EFE is controversial, although resection of EFE has been reported as part of the staged ventricular recruitment therapy. Following resection, EFE recurs and infiltrates the myocardium after primary resection. Herein we review the current experience with EFE resection.

Perioperative and Long-Term Outcomes in Patients Undergoing Synchronous Carotid Endarterectomy and Coronary Artery Bypass Grafting: A Single-Center Experience.

INTRODUCTION: Patients requiring coronary artery bypass grafting (CABG) and carotid endarterectomy (CEA) can be managed with staged (CEA before CABG), reverse staged (CABG before CEA) or synchronous treatment. This single-center retrospective study evaluated the outcomes in patients undergoing planned synchronous CEA and CABG. METHODS: Between 2000 and 2020 a total of 185 patients with symptomatic triple-vessel or left main coronary artery disease associated with 70-99% asymptomatic or 50-99% symptomatic uni- or bilateral internal carotid artery (ICA) stenosis underwent synchronous CEA and CABG at our institution. Study endpoints were defined as mortality, stroke and myocardial infarction at 30 days. Additionally, the composite endpoint of these events was investigated. RESULTS: At 30 days, mortality, stroke and myocardial infarction rates were 5.9%, 8.1% (permanent [unresolved deficit at discharge] 5.4%) and 3.8%, respectively, and the composite endpoint was reached in 13.0% of patients. Patients suffering from a stroke more frequently had a contralateral 70-99% ICA stenosis (60.0% vs. 17.3%; p < 0.001), peripheral artery disease (73.3% vs. 38.9%; p = 0.013) and prolonged cardiopulmonary bypass time (mean 119 ± 62 min vs. 84 ± 29 min; p = 0.012). Multivariate logistic regression analysis revealed the duration of cardiopulmonary bypass (odds ratio [OR] 1.024; 95% confidence interval [CI] 1.002-1.046; p = 0.034), a history of type 2 diabetes mellitus (OR 5.097; 95% CI 1.161-22.367; p = 0.031) and peripheral artery disease (OR 5.814; 95% CI 1.231-27.457; p = 0.026) as independent risk factors for reaching the composite endpoint. CONCLUSION: Patients undergoing synchronous CEA and CABG face an elevated risk of perioperative cardiovascular events, particularly an increased stroke risk in patients with symptomatic and bilateral ICA stenosis. Graphical Abstract available for this article.

The anatomic repair of recurrent aortic arch obstruction in children and adolescents.

Objective: Surgery for recurrent aortic arch obstruction is highly challenging and publications are rare. The aim of this retrospective, single-center study was to evaluate mortality, complications, and reintervention rate after an anatomic repair. Methods: Between 1999 and 2022, in total 946 operations on the aortic arch were performed at the Children's Heart Center Linz. In 39 cases, the indication was a recurrent or residual aortic arch obstruction or coarctation in a patient aged 18 years or younger. This is our study cohort. The aorta was reconstructed by a direct anastomosis/autograft in 20 patients, patch in 17 patients, and interposition graft in 2 adolescents. In 32 procedures, cardiopulmonary bypass with whole body perfusion was employed, in 4, antegrade cerebral perfusion was employed, in 2, a left heart bypass was employed, and in 1 no cardiopulmonary bypass was used. Results: Median (Q1, Q3) age at operation was 253 days (100, 2198 days), weight 7.5 kg (4.5, 17.8 kg). Median cardiopulmonary bypass time was 177 minutes (115, 219 minutes), crossclamp time 73 minutes (49, 102 minutes). Three infants died during the hospital stay: 1 with Williams syndrome, 1 with hypoplastic left heart syndrome, and 1 with heterotaxia. There was no death due to an arch complication. The main complications were 1 neurologic injury after postoperative resuscitation (Williams syndrome) and 1 permanent recurrent laryngeal nerve paralysis. During the follow-up period of median 8.1 years (2.6, 12 years) 1 re-reintervention on the aortic arch was necessary. Conclusions: Sophisticated reoperations on the aortic arch could be performed safely. In children, the growth potential of all segments of the aorta could be sustainably preserved by avoiding interposition or extra-anatomic bypass grafts.

Outcome after extracorporeal membrane oxygenation therapy in Norwood patients before the bidirectional Glenn operation.

OBJECTIVES: Patients after the Norwood procedure are prone to postoperative instability. Extracorporeal membrane oxygenation (ECMO) can help to overcome short-term organ failure. This retrospective single-centre study examines ECMO weaning, hospital discharge and long-term survival after ECMO therapy between Norwood and bidirectional Glenn palliation as well as risk factors for mortality. METHODS: In our institution, over 450 Norwood procedures have been performed. Since the introduction of ECMO therapy, 306 Norwood operations took place between 2007 and 2022, involving ECMO in 59 cases before bidirectional Glenn. In 48.3% of cases, ECMO was initiated intraoperatively post-Norwood. Patient outcomes were tracked and mortality risk factors were analysed using uni- and multivariable testing. RESULTS: ECMO therapy after Norwood (median duration: 5 days; range 0-17 days) saw 31.0% installed under CPR. Weaning was achieved in 46 children (78.0%), with 55.9% discharged home after a median of 45 (36-66) days. Late death occurred in 3 patients after 27, 234 and 1541 days. Currently, 30 children are in a median 4.8 year (3.4-7.7) follow-up. At the time of inquiry, 1 patient awaits bidirectional Glenn, 6 are at stage II palliation, Fontan was completed in 22 and 1 was lost to follow-up post-Norwood. Risk factor analysis revealed dialysis (P < 0.001), cerebral lesions (P = 0.026), longer ECMO duration (P = 0.002), cardiac indication and lower body weight (P = 0.038) as mortality-increasing factors. The 10-year mortality probability after ECMO therapy was 48.5% (95% CI 36.5-62.9%). CONCLUSIONS: ECMO therapy in critically ill patients after the Norwood operation may significantly improve survival of a patient cohort otherwise forfeited and give the opportunity for successful future-stage operations.

The right age for the en-bloc rotation of the outflow tracts: a single-centre experience.

OBJECTIVES: The en-bloc rotation of the outflow tracts (EBR) enables an anatomic correction of transposition of the great arteries with ventricular septal defect and left ventricular outflow tract obstruction. The anatomical condition or previous palliative procedures may allow choosing an elective date for the anatomic correction. The aim of this study was to evaluate the optimal age for performing the EBR based on the largest series published so far. METHODS: At the Children's Heart Center Linz, the EBR was performed in 33 patients between 2003 and 2021. Median age at operation was 74 [interquartile range (IQR) 17-627] days. Twelve patients were newborns (≤28 days), 9 older than 369 days. These 2 groups were compared to the remaining patients each regarding peri- and postoperative data, complications, reinterventions and mortality. The median follow-up period was 5.4 (IQR 0.99-11.74) years. RESULTS: In-hospital mortality was 6.1%. All-cause mortality was lower in patients younger than 369 days at the time of EBR (4.2% vs 44.4% in patients >369 days old, P = 0.013). In newborns, intensive care unit stay (median 18.5 days vs 8 days, P = 0.008) and in-hospital stay (median 29.5 days vs 15 days, P = 0.026) were significantly longer, the risk for postoperative AV block was higher (33.3 vs 0%, P = 0.012) than in patients who had been corrected anatomically after the neonatal period. CONCLUSIONS: The results of this study suggest the deferral of the EBR to the post-newborn period. A significantly higher mortality rate in patients of older age at operation seems to recommend the anatomic correction during the first year of life.

A Neonatal Heterotopic Rat Heart Transplantation Model for the Study of Endothelial-to-Mesenchymal Transition.

Endocardial fibroelastosis (EFE), defined by subendocardial tissue accumulation, has major impacts on the development of the left ventricle (LV) and precludes patients with congenital critical aortic stenosis and hypoplastic left heart syndrome (HLHS) from curative anatomical biventricular surgical repair. Surgical resection is currently the only available therapeutic option, but EFE often recurs, sometimes with an even more infiltrative growth pattern into the adjacent myocardium. To better understand the underlying mechanisms of EFE and to explore therapeutic strategies, an animal model suitable for preclinical testing was developed. The animal model takes into consideration that EFE is a disease of the immature heart and is associated with flow disturbances, as supported by clinical observations. Thus, the heterotopic heart transplantation of neonatal rat donor hearts is the basis for this model. A neonatal rat heart is transplanted into an adolescent rat's abdomen and connected to the recipient's infrarenal aorta and inferior vena cava. While perfusion of the coronary arteries preserves the viability of the donor heart, flow stagnation within the LV induces EFE growth in the very immature heart. The underlying mechanism of EFE formation is the transition of endocardial endothelial cells to mesenchymal cells (EndMT), which is a well-described mechanism of early embryonic development of the valves and septa but also the leading cause of fibrosis in heart failure. EFE formation can be macroscopically observed within days after transplantation. Transabdominal echocardiography is used to monitor the graft viability, contractility, and the patency of the anastomoses. Following euthanasia, the EFE tissue is harvested, and it shows the same histopathological characteristics as human EFE tissue from HLHS patients. This in vivo model allows for studying the mechanisms of EFE development in the heart and testing treatment options to prevent this pathological tissue formation and provides the opportunity for a more generalized examination of EndMT-induced fibrosis.

Long-term follow-up after simultaneous arterial switch operation and aortic arch repair.

OBJECTIVES: Taussig-Bing anomaly (TBA) and transposition of the great arteries (TGA) with hypoplastic or interrupted aortic arch (AA) are rare anomalies. Various operative techniques and a high incidence of reinterventions are described. The aim of this retrospective single-centre study was to evaluate operative data, mortality and reintervention rate with special regard to the AA. METHODS: At the Children's Heart Center Linz, 50 patients with the above-mentioned diagnosis have been corrected by a simultaneous repair between 2001 and 2022. Thirty-seven children had TBA, 13 had TGA and 5 of them had an interrupted AA. The median age at operation was 7 [interquartile range (IQR) 5-9] days, weight 3.38 (IQR 2.9-3.8) kg and follow-up 9.3 (IQR 3.1-14.5) years. The AA reconstruction was performed without patch material in 49 cases. RESULTS: There was 1 in-hospital mortality in a TBA patient and 1 late mortality (7 years later, neuroblastoma). 14/49 patients needed at least 1 reoperation (28.6%, all TBA) and 3 further patients had catheter reintervention or radiofrequency ablation only (6.1%, 2 TBA). Seventy-five percent of these procedures affected the right heart/pulmonary arteries; there was 1 re-coarctation repair. CONCLUSIONS: The simultaneous correction of TBA and TGA with AA obstruction or interruption is a safe operation with very low mortality. The AA reconstruction with minimized use of patch material resulted in a low restenosis rate.

Surgical and interventional rescue strategies for Fontan failure.

OBJECTIVES: Fontan patients are at lifelong risk for developing complications, which may result in Fontan failure. Survival rates after heart transplantation (HTX) are still unsatisfying in these patients. Long-term survival of extracardiac Fontan patients in the modern era was investigated. The objective of this study was to investigate if surgical and interventional procedures in patients with protein-losing enteropathy (PLE) and/or plastic bronchitis (PB) and a failing Fontan circulation can postpone or avoid HTX. METHODS: Retrospective data collection of all children who underwent a Fontan procedure between January 1999 and July 2021 at our centre was performed. Patients were surveyed regarding the occurrence of PLE or PB and their outcome was reported descriptively. HTX-free survival of patients who underwent a rescue procedure due to PLE/PB was evaluated. RESULTS: Three hundred and seventy [94.1% (95% confidence interval, 91.4-96.3)] Fontan patients were free of HTX or death at last follow-up after a median follow-up time of 6.7 years. PB/PLE was diagnosed in 34 patients during the observation period. A rescue procedure was undertaken in 16 pts. at a median time of 6.5 months (range: 1 day to 9.4 years) since the initial diagnosis of PLE/PB. In these patients, HTX-free survival was 75% (95% confidence interval, 47.6-92.7) at a median follow-up time of 4.0 years after the procedure. Range: 3.5 months to 13.9 years. CONCLUSIONS: Extracardiac Fontan patients in the modern era expect reasonable HTX-free survival rates. Surgical and/or interventional rescue strategies for Fontan failure can postpone HTX for a sustained period of time.

Outcome of patients with tetralogy of Fallot with pulmonary atresia.

Objective: Tetralogy of Fallot patients with pulmonary atresia (TOFPA) have a largely varying source of pulmonary perfusion with often hypoplastic and even absent central pulmonary arteries. A retrospective single center study was undertaken to assess outcome of these patients regarding type of surgical procedures, long-term mortality, achievement of VSD closure and analysis of postoperative interventions. Methods: 76 consecutive patients with TOFPA operated between 01.01.2003 and 31.12.2019 are included in this single center study. Patients with ductus dependent pulmonary circulation underwent primary single stage full correction including VSD closure and right ventricular to pulmonary conduit implantation (RVPAC) or transanular patch reconstruction. Children with hypoplastic pulmonary arteries and MAPCAs without double supply were predominantly treated by unifocalization and RVPAC implantation. The follow up period ranges between 0 and 16,5 years. Results: 31 patients (41%) underwent single stage full correction at a median age of 12 days, 15 patients could be treated by a transanular patch. 30 days mortality rate in this group was 6%. In the remaining 45 patients the VSD could not be closed during their first surgery which was performed at a median age of 89 days. A VSD closure was achieved later in 64% of these patients after median 178 days. 30 days mortality rate after the first surgery was 13% in this group. The estimated 10-year-survival rate after the first surgery is 80,5% ± 4,7% showing no significant difference between the groups with and without MAPCAs (p > 0,999). Median intervention-free interval (surgery and transcatheter intervention) after VSD closure was 1,7 ± 0,5 years [95% CI: 0,7-2,8 years]. Conclusions: A VSD closure could be achieved in 79% of the total cohort. In patients without MAPCAs this was possible at a significant earlier age (p < 0,01). Although patients without MAPCAs predominantly underwent single stage full correction at newborn age, the overall mortality rate and the interval until reintervention after VSD closure did not show significant differences between the two groups with and without MAPCAs. The high rate of proven genetic abnormalities (40%) with non-cardiac malformations did also pay its tribute to impaired life expectancy.

Aortic arch reconstruction in the Norwood procedure using a curved polytetrafluorethylene patch.

OBJECTIVES: The aortic arch enlargement in the Norwood procedure is classically carried out using a curved homograft patch on the inner curvature of the neoaortic arch. The study investigates the outcome of a newly used artificial patch from a vascular prosthesis as an alternative to a homograft patch. METHODS: Since April 2007, we used curved polytetrafluorethylene (PTFE) patches cut out of a prosthesis as an alternative to homograft patches for the aortic arch reconstruction. The decision for either patch material was made due to anatomic reasons, preferring PTFE patches in larger aortas. In this study, 224 Norwood patients, operated between April 2007 and April 2018, were analysed. A total of 104 patients received a PTFE patch (group PTFE), and 120 patients got a pulmonary homograft patch (group homograft). A single-centre retrospective analysis was carried out concerning postoperative course and long-term follow-up regarding aortic arch interventions and reoperations and comparing the 2 material groups. RESULTS: There were no material associated operative or postoperative complications. In-hospital mortality was 13% in group PTFE. Six children died late during follow-up (6%). One aortic isthmus dilatation (1%) was carried out 12 months after the Norwood procedure in this group, no arch reoperation was necessary during the complete follow-up. CONCLUSIONS: The curved PTFE patch showed good qualities in operative technical demands and excellent long-term results. In selected cases of hypoplastic left heart syndrome, it can be well used as alternative to the pulmonary homograft.

Valve sparing neoaortic root replacement following a Norwood type reconstruction of the aorta.

A neoaortic aneurysm after a Norwood type reconstruction of the aorta can develop due to systemic pressure on the former pulmonary artery wall. A complex valve sparing procedure can preserve native valves and avoid a valve replacement with requirement for anticoagulation. This type of operation was carried out in 3 patients, 2 of them after a Fontan palliation, 1 after a Norwood-Rastelli repair. The reconstruction was done using Dacron prostheses for the replacement of the dilated wall, similar to a Yacoub modification in 2 cases and to a David's modification in 1 patient. The postoperative course was uneventful and postoperative valve function was good in all cases.

En Block Rotation of the Outflow Tracts: Intermediate Follow-up After 15 Years of Experience.

BACKGROUND: The en bloc rotation of the outflow tracts is a surgical option for anatomic repair of transposition of the great arteries, ventricular septal defect, and left ventricular outflow tract obstruction with preserved growth potential in all tubular structures and the option for keeping the native pulmonary valve. The aim of this study was to analyze our 15-year experience with this operation. METHODS: A retrospective single-center study including 27 consecutive patients, who underwent the en bloc rotation between 2003 and 2019, was performed. Median age at operation was 103 days (interquartile range [IQR], 17-117 days), and median body weight was 5.2 kg (IQR, 3.66-8.4 kg). Six patients had undergone 1 to 4 previous operations. In 18 patients (66.7%), the pulmonary valve could be preserved, and in 9 patients (33.3%) a transannular patch was performed. Median follow-up was 5.7 years (IQR, 1.6-9.0 years). RESULTS: One patient died of chronic left ventricular failure during the hospital stay. Two more died after discharge: 1 of aspiration after a cerebral hemorrhage and 1 of sudden death. Five other patients required reoperations or had reinterventions: 1 ventricular septal defect closure, 1 aortic valve repair, 1 patch plasty, 2 dilatations of supravalvular pulmonary stenosis, and 1 stent into a left pulmonary artery. During the follow-up period, no gradient in the left ventricular outflow tract was found, and postoperative growth of the pulmonary valve was shown. CONCLUSIONS: The en bloc rotation allows an anatomic correction of the complex transposition with growth potential in all tubular structures. Reoperations or reinterventions on the pulmonary valve or on the left ventricular outflow tract have not been necessary to date.

Surgical therapy of infective endocarditis following interventional or surgical pulmonary valve replacement.

OBJECTIVES: Percutaneous pulmonary valve prostheses and right ventricle-to-pulmonary artery conduits are at risk for infective endocarditis (IE). In children and adults with a congenital heart disease, a pulmonary valve implant is frequently necessary. Prosthetic valve endocarditis is a conservatively barely manageable, serious life-threatening condition. We investigated the results of surgical pulmonary valve replacements in patients with IE. METHODS: A total of 20 patients with congenital heart disease with the definite diagnosis of IE between March 2013 and July 2020 were included in this single institutional, retrospective review. Infected conduits were 11 Melody, 5 Contegra, 3 homografts and 1 Matrix P Plus. All of the infected prosthetic material was removed from the right ventricular outflow tract up to the pulmonary bifurcation. Pulmonary homografts were implanted after pulmonary root resection as right ventricle-to-pulmonary artery conduits. RESULTS: All patients survived and were discharged infection-free. The mean time from the conduit implant to the operation for IE was 4.9 years [95% confidence interval (CI), 3.0-6.9]. The median intensive care unit stay was 3.0 days (95% CI, 2.0-4.7), and the median hospital time was 25.0 days (95% CI, 19.2-42.0). Median follow-up time was 204.5 days (range 30 days to 5 years) without death or recurrent endocarditis. CONCLUSIONS: The surgical treatment of IE of percutaneous pulmonary valve prostheses and right ventricle-to-pulmonary artery conduits is a safe and effective therapeutic concept. Early surgical referral of patients with suspicion of IE should be pursued to avoid sequelae such as right ventricular failure, septic emboli, intracardiac expansion and antibiotic resistance.

The Ross-Konno procedure in neonates and infants less than 3 months of age.

OBJECTIVES: Patients with severe left ventricular outflow tract obstruction often suffer from impaired left ventricular function, endocardial fibroelastosis and borderline-sized structures. The early Ross-Konno operation can offer complete repair due to outflow tract stenosis and enable the functional recovery and growth of small structures. METHODS: Between 2008 and March 2017, 44 early Ross-Konno procedures were performed at our centre. Thirty-five patients were neonates, and 9 were infants less than 3 months of age. A retrospective single-centre investigation was carried out analysing early and late deaths, postoperative complications and reoperations during the follow-up period. Potential prognostic influence factors as previous fetal intervention, associated lesions as presence of a VSD or hypoplastic aortic arch or severe endocardial fibroelastosis were examined. RESULTS: The in-hospital mortality rate was 7% (3 of 44), and the late mortality rate was 2%. There were no deaths in the group with ventricular septal defects (9 cases), and there was 1 death in the group with critical aortic stenosis without arch repair (1 of 24; 4%). The most deaths occurred in patients with critical aortic stenosis and aortic arch repair (3 of 11; 27%) (P = 0.012). Fifteen patients with foetal intervention had a mid-term survival rate of 87%. Reoperations were necessary in 19 of 40 surviving patients during a mean follow-up period of 5.9 years. CONCLUSIONS: The early Ross-Konno procedure can enable biventricular repair even in borderline left ventricles with good long-term outcome. Thus far, there were no reoperations at the level of the autograft or the left ventricular outflow tract in our cohort. The highest operative risk was observed in patients with critical aortic stenosis and aortic arch hypoplasia.

Unplanned cardiac reoperations and interventions during long-term follow-up after the Norwood procedure†.

OBJECTIVES: Patients with hypoplastic left heart syndrome or related malformations are predominantly treated with a 3-stage palliation. Anatomic or physiologic problems can lead to unplanned additional surgical or catheter interventions during single ventricle palliation. Changes in operative technique may have an impact on the reoperation rate. METHODS: Between 1997 and 2014, 317 Norwood procedures were performed at our centre. A retrospective single centre investigation was carried out concerning incidence, timing, indication and type of unplanned interstage cardiac reoperations and catheter interventions during follow-up of Norwood patients. Patients were followed from birth until the end of 2015. Cardiac procedures taking place at the time of the bidirectional Glenn or Fontan procedure or heart transplantation were not included. RESULTS: Sixty-five of the Norwood patients (20.5%) had at least one additional surgical cardiac procedure. Nine patients (2.8%) needed open procedures prior to the Norwood operations, 11.0% had procedures in the interstage I, 3.5% in the interstage II and 9.1% of the Fontan patients had cardiac reoperations afterwards. Main indications for unplanned surgery were insufficient pulmonary perfusion and tricuspid regurgitation. Eighty-one patients (25.6%) had at least one interstage catheter intervention during follow-up mainly addressing stenosis of the pulmonary arteries, aortic arch stenosis or aortopulmonary collaterals. CONCLUSIONS: The number of unplanned reoperations and interventions during staged palliation is remarkably high showing surgical peaks in the interstage I and after the Fontan procedure and an interventional peak in the interstage II. Thorough early information of the parents about possibly anticipated additional procedures is necessary.