Palliated Hypoplastic Left Heart Syndrome Patients Experience Superior Waitlist and Comparable Post-Heart Transplant Survival to Non-Single Ventricle Congenital Heart Disease Patients

Congenital heart disease (CHD) is a well-established risk factor for inferior waitlist and post-heart transplant survival in children. Differences in outcomes between CHD subgroups are understudied. The present study compared outcomes for palliated hypoplastic left heart syndrome (HLHS) patients to other non-single ventricle CHD (non-SVCHD) and non-CHD patients. United Network for Organ Sharing was used to identify children (age < 18) listed for heart transplant in the United States between 2016 and 2021. CHD sub-diagnoses were only available for United Network for Organ Sharing status 1a after 2015, thereby defining the cohort. Waitlist outcomes were studied using competing-risk time-to-event analysis for transplantation, mortality/decompensation, and alive-on-waitlist. Multivariable Cox proportional hazards regression analyses were used to identify factors associated with inferior post-transplant survival. Patients included: palliated-HLHS (n = 477), non-SVCHD (n = 686), and non-CHD (n = 1261). At listing, Palliated-HLHS patients were older than non-SVCHD (median 2-year [IQR 0-8] vs median 0-year [0-3], respectively) and younger than non-CHD (median 7-year [0-14]) (P < 0.001 vs both), and were more likely to be white (P < 0.01 vs both). Upon time-to-event analysis, rates of waitlist mortality/decompensation rates were greater among non-SVCHD than palliated-HLHS. Post-transplant survival was comparable between palliated-HLHS and non-SVCHD (P = 0.920) but worse compared to non-CHD (P < 0.001). Both palliated-HLHS (HR 2.40 [95% CI 1.68-3.42]) and non-SVSCHD (2.04 [1.39-2.99]) were independently associated with post-transplant mortality. Palliated-HLHS patients with heart failure experience significantly worse post-transplant outcomes than non-CHD but, compared to other CHD patients, experience superior waitlist and comparable post-transplant survival. While a high-risk cohort, HLHS patients can achieve gratifying waitlist and post-transplant survival.

Failures of the Fontan System in Univentricular Hearts and Mortality Risk in Heart Transplantation: A Systematic Review and Meta-Analysis

The Fontan procedure (FP) is the standard surgical treatment for Univentricular heart diseases. Over time, the Fontan system fails, leading to pathologies such as protein-losing enteropathy (PLE), plastic bronchitis (PB), and heart failure (HF). FP should be considered as a transitional step to the final treatment: heart transplantation (HT). This systematic review and meta-analysis aims to establish the risk of death following HT according to the presence of FP complications. There was a total of 691 transplanted patients in the 18 articles, immediate survival 88% (n = 448), survival from 1 to 5 years of 78% (n = 427) and survival from 5.1 to 10 years of 69% (n = 208), >10 years 61% (n = 109). The relative risk (RR) was 1.12 for PLE (95% confidence interval [CI] = 0.89-1.40, p = 0.34), 1.03 for HF (0.7-1.51, p = 0.88), 0.70 for Arrhythmias (0.39-1.24, p = 0.22), 0.46 for PB (0.08-2.72, p = 0.39), and 5.81 for CKD (1.70-19.88, p = 0.005). In patients with two or more failures, the RR was 1.94 (0.99-3.81, p = 0.05). After FP, the risk of death after HT is associated with CKD and with the presence of two or more failures.

Fate of patients with single ventricles who do not undergo the Fontan procedure

BACKGROUND

The Fontan procedure, the last of a series of palliative operations for patients born with single ventricles, is associated with a significant late burden of complications. There are other strategies for patients who are suboptimal candidates for Fontan completion, however the long-term outcomes of these different surgical options have not been clearly elucidated. We performed a systematic literature review to establish the current role of other treatment approaches besides the Fontan procedure.

METHODS

MEDLINE and Embase databases were systematically searched for articles describing the long-term outcomes of patients with single ventricles who have not received the Fontan procedure.

RESULTS

A total of 36 articles met all inclusion criteria. There is a scarcity of contemporary data on the non-Fontan cohort. Historical studies provided a significant contribution.

CONCLUSIONS

Long-term survival in unoperated patients with single ventricles is possible under the rare conditions of having balanced hemodynamics. Up to half of patients may survive on only a systemic-to-pulmonary artery shunt or bidirectional cavopulmonary shunt for over 20 years with reasonable functional status. In patients with a failing single ventricle, the bidirectional cavopulmonary shunt is an excellent bridge to heart transplantation and may provide better post-transplant survival than those with a Fontan circulation. Currently, the Fontan procedure continues to be the best definitive palliation for patients born with single ventricle lesions. However, for those with borderline indications, other strategies should be carefully considered.

Anesthesia for Pediatric Heart Transplantation: Are Patients With a Failing Hemi-Fontan- or Fontan-Physiology Different?

Background. The absolute number of patients presenting with failure of the hemi-Fontan or Fontan circulation for cardiac transplantation (cTx) will continuously rise. We aimed to analyze the intraoperative differences in patients undergoing cTx for a failing hemi-Fontan or Fontan circulation (group A) with those undergoing cTx for cardiomyopathy and congenital heart disease (group B). Methods. Data of patients undergoing cTx during a 10-year period were compared between group A and group B patients. Results. cTx was performed in 83 patients (group A, n = 21; group B, n = 62). Surgical times including median incision-suture time (549 minutes vs 386 minutes, P < .05) and median organ ischemia time (305 minutes vs 233 minutes, P < .05) were longer in group A patients. After weaning off cardiopulmonary bypass a higher median modified Vasoactive Inotropic Score (16 vs 10, P < .05) was necessary in group A patients. During surgery more fresh frozen plasma (44 mL/kg vs 20 mL/kg, P < .05), platelet concentrates (20 mL/kg vs 14 mL/kg, P < .05), and coagulation factor concentrates were given in group A patients. Mortality during the first 90 days after cTx was higher in group A (23.8% vs 6.5%, P < .05). Conclusion. Patients undergoing cTx for a failing hemi-Fontan or Fontan circulation are challenging. They require an intensive vasoactive and inotropic support; furthermore, special attention should be paid to the management of bleeding complications. cTx for this group of patients is associated with higher 90 days mortality.

Hybrid stage 1 palliation as a bridge to cardiac transplantation in patients with high-risk single ventricle physiology

BACKGROUND

The hybrid stage 1 palliation for hypoplastic left heart syndrome (HLHS) was first described in 1993 as a bridge to heart transplant for HLHS. There are limited data on this strategy as primary heart transplantation for HLHS has become less common.

METHODS

This is an observational, single-center study comparing pre- and post-transplant outcomes of patients listed for transplant following hybrid palliation with those following surgical stage 1 palliation.

RESULTS

From 2004 to 2017, 21 patients underwent hybrid palliation as a bridge to heart transplant and 28 patients were listed for transplant following surgical stage 1 palliation or aortic arch repair and pulmonary artery band placement. Premature birth and the presence of genetic or anatomic abnormalities were more common in the hybrid group. Need for extracorporeal membrane oxygenation (ECMO) support and ventricular dysfunction was more common in the surgical group. There was a trend toward shorter waitlist times in the surgical cohort (36 days vs 70 days, P = 0.06). There was no difference in waitlist mortality (19% vs 21%, P = 0.61). Survival at 1 and 5 years post-transplant was similar for the hybrid and surgical cohorts (5-year survival, 80% vs 85%, P = 0.94, respectively). There was no difference in the number of post-transplant interventions.

CONCLUSIONS

Although the hybrid patients represented a higher risk cohort and demonstrated longer wait times, the waitlist and post-transplant mortality was equivalent between the two groups. For high-risk patients, the hybrid palliation as a bridge to transplant appears to be a reasonable strategy.

Orthotopic heart transplantation in children

Heart transplantation is a relatively infrequent but technically demanding procedure in pediatric cardiac surgery. Orthotopic heart transplantation is often offered to older children or adolescents following multiple previous operations, but with advances in intensive care, diagnostics, and management, more infants with complex congenital heart diseases are being listed for transplantation. Primary cardiomyopathies remain the most common indication. Outcomes following cardiothoracic transplantation have improved steadily in recent times. Donor availability has been helped by increasing public awareness and donation after cardiac death, especially of lungs, increasing the number of patients benefiting from heart and/or lung transplantation. While there are still insufficient donors to meet the current needs, effective devices to bridge patients to transplantation are now widely used. Although the many advances have improved the outlook of transplantation, there are still difficulties that have not changed over time. Nevertheless, heart transplantation in children carries a reasonably good survival rate over the entire spectrum of recipient heart conditions. We discuss the salient features of acceptance of an organ and the technical aspects of both simple and complex heart transplantation in children.

The Infant with Aortic Arch Hypoplasia and Small Left Heart Structures: Echocardiographic Indices of Mitral and Aortic Hypoplasia Predicting Successful Biventricular Repair

In infants with aortic arch hypoplasia and small left-sided cardiac structures, successful biventricular repair is dependent on the adequacy of the left-sided structures. Defining accurate thresholds of echocardiographic indices predictive of successful biventricular repair is paramount to achieving optimal outcomes. We sought to identify pre-operative echocardiographic indices of left heart size that predict intervention-free survival in infants with small left heart structures undergoing primary aortic arch repair to establish biventricular circulation (BVC). Infants ≤2 months undergoing aortic arch repair from 1999 to 2010 with aortic and/or mitral valve hypoplasia, (Z-score ≤-2) were included. Pre-operative and follow-up echocardiograms were reviewed. Primary outcome was successful biventricular circulation (BVC), defined as freedom from death, transplant, or single ventricular conversion at 1 year. Need for catheter based or surgical re-intervention (RI), valve annular growth, and significant late aortic or mitral valve obstruction were additional outcomes. Fifty one of 73 subjects (79%) had successful BVC and were free of RI at 1 year. Seven subjects failed BVC; four of those died. The overall 1 year survival for the cohort was 95%. Fifteen subjects underwent a RI but maintained BVC. In univariate analysis, larger transverse aorta (p = 0.006) and aortic valve (p = 0.02) predicted successful BVC without RI. In CART analysis, the combination of mitral valve (MV) to tricuspid valve (TV) ratio ≤0.66 with an aortic valve (AV) annulus Z-score ≤-3 had the greatest power to predict BVC failure (sensitivity 71%, specificity 94%). In those with successful BVC, the combination of both AV and MV Z-score ≤-2.5 increased the odds of RI (OR 3.8; CI 1.3-11.4). Follow-up of non-RI subjects revealed improvement in AV and MV Z-score (median AV annulus changed over time from -2.34 to 0.04 (p < 0.001) and MV changed from -2.88 to -1.41 (p < 0.001), but residual mitral valve stenosis and aortic arch obstruction were present in one-third of subjects. In this cohort of infants requiring initial aortic arch repair with concomitant small left heart structures, successful BVC can be predicted from combined echocardiographic indices. In this complex population, 1 year survival is high, but the need for RI and the presence of residual lesions are common.

Split-graft technique in neonatal heart transplant for aortic atresia

We describe a neonate with aortic atresia and hypoplastic aorta, listed for heart transplant after extracorporeal membrane oxygenation resuscitation and ductal stenting. The donor aorta was detached from the graft, after an isolated arch reconstruction prior to the transplant itself in a routine fashion. To the best of our knowledge, this is the first reported case of neonatal arch reconstruction before transplantation performed with grafts from the same donor in a split-way strategy.

Impact of initial Norwood shunt type on young hypoplastic left heart syndrome patients listed for heart transplant: A multi-institutional study

BACKGROUND

Pulmonary blood flow during Stage 1 (Norwood) palliation for hypoplastic left heart syndrome (HLHS) is achieved via modified Blalock-Taussig shunt (MBT) or right ventricle to pulmonary artery conduit (RVPA). Controversy exists regarding the differential impact of shunt type on outcome among those who require transplantation early in life. In this study we explored waitlist and post-transplant outcomes within this sub-population stratified by shunt type.

METHODS

Eligible patients were enrolled through the Pediatric Heart Transplant Study (PHTS) database. Patients included those listed for heart transplantation at 1 of 35 participating centers, all of whom were <6 years of age and with a diagnosis of HLHS (and variants) status post Stage 1 palliation with MBT or RVPA. Standard risk factors for death were analyzed using multivariable hazards modeling.

RESULTS

Between 2010 and 2013, 190 patients were identified. Compared with the RVPA group (n = 111), the MBT group (n = 79) was less likely to have undergone a Glenn palliation (41% vs 73%, p < 0.001), were younger at listing (median age 1.3 vs 1.8 years, p = 0.05), had lower median weight (7.9 vs 9.4 kg, p = 0.02), and were more likely to be mechanically ventilated at listing (35% vs 22%, p = 0.04). There were no significant differences in median waitlist time (1.7 vs 2.6 months, p = 0.2) or rate of transplantation (61% vs 60%, p = 1.0). Among waitlisted patients, 3-month survival was less for MBT compared with RVPA patients (74% vs 91%, p = 0.02). Patients who had not yet achieved Glenn palliation before listing had lower waitlist 3-month survival (76% vs 90%, p = 0.02). In MBT infants <1 year old, there was a trend toward improved survival in those with Glenn palliation compared to those without (100% vs 68%, p = 0.08). Early post-transplant mortality rates were similar between the RVPA and MBT groups (p = 0.4) with overall survival 84% at 1 year.

CONCLUSIONS

Among HLHS patients, the need for transplant before Glenn palliation is associated with poorer waitlist survival. Waitlist survival is poorer in the MBT group, with this difference driven by pre-Glenn MBT infants. Post-transplant outcomes were unaffected by shunt type.

Analysis of preoperative condition and interstage mortality in Norwood and hybrid procedures for hypoplastic left heart syndrome using the Aristotle scoring system

OBJECTIVE

The 'hybrid procedure', consisting of surgical banding of the pulmonary arteries with intraoperative stenting of the arterial duct, was developed as primary palliation in hypoplastic left heart syndrome (HLHS), avoiding the risks of cardiopulmonary bypass. In many centres, it is reserved for low birth weight, premature or unstable neonates; however, its role in such high risk cases of HLHS has yet to be defined.

METHODS

The preoperative condition of all patients with HLHS who underwent either the hybrid or the Norwood procedure for HLHS between 2005-2011 was analysed retrospectively, using a modified comprehensive Aristotle score. We then compared operative, interstage and 1 year mortalities between the groups after Aristotle adjustment via Cox proportional hazards analyses.

RESULTS

Of 138 patients with HLHS, 27 had hybrid and 111 Norwood procedures. The hybrid group had significantly higher Aristotle scores (mean 4.1 vs 1.8; p<0.001); however, there was no significant difference in mortality at any stage. At 1 year, the overall unadjusted survival among Norwood and hybrid patients was 58.6% and 51.9%, respectively, yielding an Aristotle adjusted hazard ratio for mortality among hybrid patients of 1.09 (95% CI 0.56 to 2.11, p=0.80).

CONCLUSIONS

Applying a hybrid approach to high risk patients with HLHS produces a comparable early and interstage mortality risk to lower risk patients undergoing the Norwood procedure. Prospective studies are needed to establish whether the hybrid procedure is a viable alternative to the Norwood procedure in all HLHS patients in terms of both mortality and long term morbidity.

Hypoplastic left heart syndrome - unresolved issues

Hypoplastic left heart syndrome (HLHS) is one of the most challenging congenital heart defects. At present, it is expected that - at best - 70% of newborns with HLHS will reach adulthood. This review addresses the problems of right ventricular (RV) failure and insufficient growth of pulmonary vasculature in these patients. In order to further improve long-term prognosis translational research to control RV function, growth of pulmonary arteries and progress in chronic circulatory support are clearly needed to provide a further improvement for adults with HLHS.

Anesthetic Considerations in Infants With Hypoplastic Left Heart Syndrome

Hypoplasia of the left ventricle is a congenital cardiac lesion that is almost universally fatal if left untreated. Six decades of improved diagnostic modalities, greater understanding of single ventricle physiology, and earlier surgical and palliative options have given many of these patients an opportunity of surviving well into adulthood. This review will summarize these advances and focus on the anesthetic implications of this challenging disease from diagnosis to beyond the first palliative surgery.