Hybrid Palliation: Outcomes After the Comprehensive Stage 2 Procedure

Hybrid Interventions in Congenital Heart Disease

Hybrid interventions in congenital heart disease (CHD) embody the inherent collaboration between congenital interventional cardiology and cardiothoracic surgery. Hybrid approaches to complex and common lesions provide the opportunity to circumvent the limitations of patient size, vascular access, severity of illness, and anatomy that would otherwise be prohibitive to surgical and percutaneous techniques alone. This review describes several important hybrid approaches to interventions in CHD.

Utility of the NEONATE Score at an Institution that Routinely Performs the Hybrid Procedure for Hypoplastic Left Heart Syndrome

NEONATE score > 17 has been proposed as a risk factor for interstage mortality/cardiac transplant (IM/T) for patients with single ventricle physiology. Hybrid procedure is assigned 6 points, the highest possible score for that surgical variable. Most centers reserve the hybrid procedure for high-risk patients. Goal of this study was to evaluate the NEONATE score at a center that routinely performs the hybrid procedure. Retrospective chart review of patients undergoing the hybrid procedure was performed (2008-2021). Demographics and variables used for the NEONATE score were collected. Maximization of Youden's J Statistic used to determine cohort-specific optimal threshold for patients undergoing comprehensive Stage II procedure (H-CSII) versus those with IM/T (H-IM/T). Total of 120 patients met inclusion criteria (H-CSII = 105, H-IM/T = 15). Gestational age was median 39 weeks (IQR 38, 39) and birth weight was 3.18 kg (2.91, 3.57). No patient was discharged with opiates or required post-operative extracorporeal circulatory support. Optimal threshold, as selected by maximizing Youden's J Statistic, was 22. Score > 22 had a positive predictive value of 0.33 (95% CI 0.12-0.62), negative predictive values of 0.90 (95% CI 0.83-0.95), and accuracy of 0.83 (95% CI 0.75-0.90) for IM/T. At a center that routinely performs the hybrid procedure, value of > 22 had the highest accuracy. This suggests that the hybrid procedure is not necessarily intrinsically a risk-factor for IM/T, but rather patient selection for the hybrid procedure may play a larger role at centers that do not routinely perform this procedure.

Long-term outcomes of hypoplastic left heart syndrome with analysis of the Norwood procedure in infants following bilateral pulmonary artery banding

Objective

To investigate the early and long-term outcomes of the deferred Norwood procedure by bilateral pulmonary artery banding (BPAB) versus the neonatal Norwood procedure.

Methods

This retrospective study examined 46 patients with hypoplastic left heart syndrome and its variants undergoing the Norwood procedure for single ventricle physiology between 2004 and 2022 at 3 institutions. The patients were divided into 2 groups: neonatal Norwood procedure (group N; n = 23) and staged Norwood procedure in infants following BPAB (group I; n = 23). Preoperative risk factors, surgical results, survival rates, Fontan candidacy, and long-term complications were compared.

Results

Early survival rates after the Norwood procedure were 91.3% (21 of 23) in both groups. Late survival rates after the Norwood procedure were similar at the 10-year follow-up (group N, 76.3%; group I, 68.7%; P = .63). Fontan completion rates also were comparable in the 2 groups (group N, 77.8%; group I, 85.7%; P = .67). Group N showed a higher median pulmonary artery (PA) index before bidirectional cavopulmonary connection (group N, 177 [interquartile range (IQR), 147-243] mm2/m2; group I, 152 [IQR, 146-163] mm2/m2; P = .03); this trend continued until 5 years after Fontan completion (P = .01). Group N also had a lower rate of freedom from protein-losing enteropathy (PLE) at 9.0 years after the Fontan operation (90.0% vs 52.5% for group I; P = .04), although the incidences of other Fontan-associated events were not significantly different.

Conclusions

Fontan candidacy and survival rates were similar regardless of the timing of the Norwood procedure. Early performance of the Norwood procedure may lead to lower rates of late Fontan-associated events, such as PLE.

Norwood operation versus comprehensive stage II after bilateral pulmonary artery banding palliation for infants with critical left heart obstruction

OBJECTIVE

To determine patient characteristics and outcomes after Norwood versus comprehensive stage II (COMPSII) for infants with critical left heart obstruction who had prior hybrid palliation (bilateral pulmonary artery banding ± ductal stent).

METHODS

From 23 Congenital Heart Surgeons' Society institutions (2005-2020), 138 infants underwent hybrid palliation followed by either Norwood (n = 73, 53%) or COMPSII (n = 65). Baseline characteristics were compared between Norwood and COMPSII groups. Parametric hazard model with competing risk methodology was used to determine risk and factors associated with outcomes of Fontan, transplantation, or death.

RESULTS

Infants who underwent Norwood versus COMPSII had a higher prevalence of prematurity (26% vs 14%, P = .08), lower birth weight (median 2.8 vs 3.2 kg, P < .01) and less frequent ductal stenting (37% vs 99%; P < .01). Norwood was performed at a median age of 44 days and median weight of 3.5 kg, versus COMPSII at 162 days and 6.0 kg (both P < .01). Median follow-up was 6.5 years. At 5 years after Norwood and COMPSII, respectively; 50% versus 68% had Fontan (P = .16), 3% versus 5% had transplantation (P = .70), 40% versus 15% died (P = .10), and 7% versus 11% are alive without transition, respectively. For factors associated with either mortality or Fontan, only preoperative mechanical ventilation occurred more frequently in the Norwood group.

CONCLUSIONS

Higher prevalence of prematurity, lower birth weight, and other patient-related characteristics in the Norwood versus COMPSII groups may influence differences in outcomes that were not statistically significant for this limited risk-adjusted cohort. The clinical decision regarding Norwood versus COMPSII after initial hybrid palliation remains challenging.

Initial Counseling Prior to Palliation for Hypoplastic Left Heart Syndrome: 2021 vs 2011

We sought to examine current practices and changes in practice regarding initial counseling for families of patients with hypoplastic left heart syndrome (HLHS) given the evolution of options and outcomes over time. Counseling (Norwood with Blalock-Taussig-Thomas shunt (NW-BTT), NW with right ventricle to pulmonary artery conduit (NW-RVPA), hybrid palliation, heart transplantation, or non-intervention/hospice (NI)) for patients with HLHS were queried via questionnaire of pediatric care professionals in 2021 and compared to identical questionnaire from 2011. Of 322 respondents in 2021 (39% female), 299 respondents were cardiologists (92.9%), 17cardiothoracic surgeons (5.3%), and 6 were nurse practitioners (1.9%). Respondents were largely from North America (96.9%). In 2021, NW-RVPA procedure was the preferred palliation for standard risk HLHS patient (61%) and was preferred across all US regions (p < 0.001). NI was offered as an option by 71.4% of respondents for standard risk patients and was the predominant strategy for patients with end-organ dysfunction, chromosomal abnormality, and prematurity (52%, 44%, and 45%, respectively). The hybrid procedure was preferred for low birth-weight infants (51%). In comparison to the identical 2011 questionnaire (n = 200), the NW-RVPA was endorsed more in 2021 (61% vs 52%, p = 0.04). For low birth-weight infants, hybrid procedure was more recommended than in 2011 (51% vs 21%, p < 0.001). The NW-RVPA operation is the most recommended strategy throughout the US for infants with HLHS. The hybrid procedure for low birth-weight infants is increasingly recommended. NI continues to be offered even in standard risk patients with HLHS.

Incidence of and Risk Factors for Aortic Arch Interventions After the Comprehensive Stage II Procedure for Hypoplastic Left Heart Syndrome

Minimal data exist about the incidence and risk factors for arch intervention after comprehensive stage II (CSII). Goal of this study was to document incidence of arch interventions after CSII and determine if any differences existed between those who underwent an arch intervention (aiCSII) versus those did not have an intervention. Single-center retrospective chart review of all hypoplastic left heart syndrome patients who underwent a CSII between 6/1/2005 and 2/1/2020 was performed. Univariate analysis was conducted in addition to principal components analysis (PCA). One hundred patients were evaluated. Sixteen patients underwent 24 arch interventions. Age at initial arch reintervention was 1.3 ± 1.2 years (median 1.0 years, range 0.5-2.2 years). Univariate analysis showed that the aiCSII group were more likely to be female, to have had a retrograde arch intervention post-hybrid procedure, and to be younger at time of CSII. On echocardiograms, aiCSII group had significantly higher pre-CSII patent ductus arteriosus velocities, arch velocities on their 1st post-operative and discharge study post-CSII, and arch velocities pre-Fontan. Gradients were higher in the aiCSII via pre-Fontan catheterization. With PCA, echocardiographic and catheterization data remained significantly associated with aiCSII versus those who did not undergo an arch intervention (OR = 4.5 (1.9, 19.8), p = 0.008). Incidence of arch intervention post-CSII was 16%. Echocardiographic arch velocities during the CSII hospitalization were the strongest predictors for subsequent aortic arch interventions. Further studies are needed to determine any modifiable variables that may reduce the incidence of arch interventions.

Incidence and impact of acute kidney injury in patients with hypoplastic left heart syndrome following the hybrid stage 1 palliation

OBJECTIVE

Acute kidney injury leads to worse outcomes following paediatric cardiac surgery. There is a lack of literature focusing on acute kidney injury after the Hybrid stage 1 palliation for single ventricle physiology. Patients undergoing the Hybrid Stage 1, as a primary option, may have a lower incidence of kidney injury than previously reported. When present, kidney injury may increase the risk of post-operative morbidity and mortality.

METHODS

A retrospective, single centre review was conducted in patients with hypoplastic left heart syndrome who underwent Hybrid Stage 1 from 2008 to 2018. Acute kidney injury was defined as a dichotomous yes (meeting any injury criteria) or no (no injury) utilising two different criteria utilised in paediatrics. The impact of kidney injury on perioperative characteristics and 30-day mortality was analysed.

RESULTS

The incidence of acute kidney injury is 13.4-20.7%, with a severe injury rate of 2.4%. Patients without a prenatal diagnosis of hypoplastic left heart syndrome have a higher incidence of kidney injury than those prenatally diagnosed, (40% versus 14.5%, p = 0.024). Patients with acute kidney injury have a significantly higher incidence of 30-day mortality, 27.3%, compared to without, 5.6% (p = 0.047).

DISCUSSION

The incidence of severe acute kidney injury after the Hybrid Stage 1 palliation is low. A prenatal diagnosis may be associated with a lower incidence of kidney injury following the Hybrid Stage 1. Though uncommon, severe acute kidney injury following Hybrid Stage 1 may be associated with higher 30-day mortality.

Biventricular Conversion in the Borderline Hypoplastic Heart

PURPOSE OF REVIEW

The development of biventricular repair and conversion pathways for patients with borderline hypoplastic heart disease represents an area of recent inquiry and innovation. This review summarizes emerging techniques and novel treatment algorithms for borderline hypoplastic heart disease with a focus on surgical advances within the last 10 years.

RECENT FINDINGS

Many patients with borderline hypoplastic heart disease are amenable to primary biventricular repair, or biventricular conversion following single-ventricle palliation coupled with ventricular rehabilitation strategies. New insights into the potential for growth and recovery of borderline ventricles have been uncovered. However, questions remain regarding optimal patient selection and the long-term outcomes of select patient groups treated with single-ventricle palliation versus biventricular repair/conversion or transplantation. Efforts to direct a greater proportion of borderline hypoplastic heart patients towards a biventricular circulation are accelerating and represent important avenues for progress and future research in the field of congenital heart disease.

Evolution of care pathways for babies with hypoplastic left heart syndrome: integrating mechanistic and clinical process investigation, standardization, and collaborative study

Since initial descriptions of staged palliation for hypoplastic left heart syndrome (HLHS) in the 1980’s, much has been learned about the pathophysiology of the single ventricle circulation. New therapies that leverage systems biology and clinical derivatives have been developed. While in-hospital mortality and morbidity for babies with HLHS have continued to improve, there remains a long (and daresay winding) road ahead to achieve ideal outcomes. Important variation in even these abbreviated in-hospital metrics persists among institutions and currently utilized prediction models explain only a small amount of this variation. Moreover, long-term survival and neurodevelopmental health for patients with HLHS are infrequently reported and remain suboptimal despite improved in-hospital outcomes. This focused review will describe the evolution of national outcomes for HLHS over time and the potential factors motivating improved time-related mortality. Emerging modifiable risk-factors that hold promise in terms of moving the needle for long-term success, including social determinants of health and the delineation of genetic profiles, will be discussed. Specifically, this review will integrate contemporary data based on the first murine HLHS models that suggest a genetically elicited modular phenotype with environmental factors known to impact the initial durability of surgical therapies. A comprehensive approach to the management of HLHS, which leverages both proactive transplantation and hybrid palliation, in addition to traditional Norwood palliation, will be emphasized to extend and match management to the complete spectrum of patient risk-profiles. Finally, we will explore the critical role that national collaboratives and quality reporting initiatives have played in improving outcomes and shifting the focus to more meaningful long-term survival and neurodevelopment.

Systolic/diastolic ratio correlates with end diastolic pressures in pediatric patients with single right ventricles

BACKGROUND

Increased ventricular end-diastolic pressure (VEDP) is a known risk factor for morbidity and mortality in patients with single right ventricle (RV) physiology. Previous studies have shown mixed results correlating echocardiographic measurements with catheter-derived VEDP in this population. Goal of this study was to evaluate if echocardiographic systolic/diastolic ratio (S/D) correlated with VEDP.

METHODS

Patients with single RV physiology who underwent simultaneous echocardiography and catheterization were evaluated. Systolic and diastolic durations were measured using tricuspid inflow durations from Doppler analysis to calculate the S/D ratio. VEDP was obtained from the catheterization report.

RESULTS

Twenty-seven studies were performed on patients with single RV physiology. Median age at time of catheterization was 11.4 months (range, 0-132 months). Mean VEDP was 9.9 ± 4.5 mm Hg. S/D ratio was 1.8 ± 0.5. S/D ratio significantly correlated with VEDP (r = 0.63, P < .01). Optimum value of S/D ratio for discriminating between patients with high (>10 mm Hg) vs low EDP was found to be 1.9. High S/D ratio had an area under the curve of 0.82 (0.65, 1.0), with 75% sensitivity and 89% specificity for predicting elevated VEDP.

CONCLUSION

In patients with single RV physiology, S/D significantly correlated with VEDP. S/D ratio is a simple technique that may be useful in both estimating and discriminating between high and low VEDP in this complex patient population.