Does Ascending Aorta Size Affect Norwood Outcomes in Hypoplastic Left Heart With Aortic Atresia?

Long-term impact of anatomic subtype in hypoplastic left heart syndrome after Fontan completion

BACKGROUND

Aortic atresia (AA)/mitral stenosis (MS) is a well-known risk factor for survival after Norwood; however, the effect of anatomical subtypes in those who survive surgical palliation is unknown.

METHODS

We performed a retrospective single-center study of patients with classic hypoplastic left heart syndrome (HLHS) who underwent Fontan at our center between August 1989 and July 2017. Clinical outcomes, as well as ventricular and atrioventricular-valve (AVV) function, were determined for each patient, and the effects of HLHS subtype were estimated using multivariable statistical analyses.

RESULTS

We included 418 patients with HLHS (AA/mitral atresia [MA] 153, AA/MS 100, aortic stenosis [AS]/MS 154, and AS/MA 11). The median follow-up period was 8.6 (interquartile range, 2.9-15.8) years. Overall transplant-free survival, cumulative incidence of AVV failure, and ventricular failure, which were defined by moderate dysfunction or greater or the necessity of surgical interventions, were 70.1%, 35.9%, and 17.9% at 20 years, respectively. Of the 3 major subtypes, AA/MS was associated with lower survival rate (AA/MA 74.6% vs AS/MS 79.1% vs AA/MS 56.1% at 17 years, P = .04). The subanalysis between AA/MA and AA/MS revealed AA/MS tended to have a greater rate of ventricular failure without a significant difference of AVV failure (AA/MA 11.2% vs AA/MS 26.2% at 17 years, P = .053).

CONCLUSIONS

The survival risk of the anatomic subtype AA/MS persisted long term after Fontan completion and was likely due to a greater rate of single ventricle rather than AVV failure. These findings suggest that the abnormal pressure overload condition of the hypoplastic left ventricle created by AA/MS has a detrimental effect on single right ventricle function.

Hypoplastic Left Heart Syndrome with Mitral Stenosis and Aortic Atresia-Echocardiographic Findings and Early Outcomes

BACKGROUND

Mitral stenosis/aortic atresia (MS/AA) has been reported as a high-risk variant of hypoplastic left heart syndrome (HLHS), potentially related to ventriculocoronary connections (VCCs) or endocardial fibroelastosis (EFE) and myocardial hypoperfusion. We aimed to identify echocardiographic and clinical factors associated with early death or transplant in this group.

METHODS

Patients with HLHS MS/AA treated at our center between 2000 and 2020 were included. Pre-stage I palliation echocardiograms were reviewed. Certain imaging factors, such as determination of VCC, EFE, and measurement of tricuspid annular plane systolic excursion were measured from retrospective review of preoperative images; others were derived from clinical reports. Groups were compared according to primary outcome of death or transplant prior to stage II palliation.

RESULTS

Of 141 patients included, 39 (27.7%) experienced a primary outcome. Ventriculocoronary connections were identified in 103 (73.0%) patients and EFE in 95 (67.4%) patients. Among imaging variables, smaller ascending aorta size (median, 2.2 [interquartile range (IQR) 1.7-2.8] vs 2.6 [2.2-3.4] mm, P = .01) was associated with primary outcome. There was similar frequency of VCC (74.4% vs 72.5%, P = .83), EFE (59.0% vs 72.5%, P = .19), moderate or greater tricuspid regurgitation (5.1% vs 5.9%, P = 1.00), and similar right ventricular systolic function (indexed tricuspid annular plane systolic excursion 32.5 ± 7.3 vs 31.4 ± 7.2 mm/m2, P = .47) in the primary outcome group compared to other patients. Clinical factors associated with primary outcome included lower birth weight (mean, 2.8 ± SD 0.8 vs 3.3 ± 0.5 kg, P = .0003), gestational age <37 weeks (31.6% vs 4.9%, P < .0001), longer cardiopulmonary bypass time (median, 112 [IQR, 93-162] vs 82 [71-119] minutes, P = .001), longer intensive care unit length of stay (median, 19 [IQR, 10-30] vs 10 [7-15] days, P = .001), and extracorporeal membrane oxygenation following stage I palliation (43.6% vs 8.8%, P < .0001). Presence of VCCs and EFE was not associated with death or transplant after controlling for birth weight and era of stage I palliation.

CONCLUSIONS

In one of the largest reported single-center cohorts of HLHS MS/AA, there were few pre-stage I palliation imaging characteristics associated with primary outcome. Imaging findings evaluated in this study, including the presence of VCC and/or EFE as determined using highly sensitive echocardiogram criteria, should not preclude intervention, although impact on long-term outcomes requires further evaluation.

Short-Term Outcomes, Functional Status, and Risk Factors for Requiring Extracorporeal Life Support After Norwood Operation: A Single-Center Retrospective Study

Patients requiring extracorporeal life support (ECLS) post-Norwood operation constitute an extremely high-risk group. We retrospectively described short-term outcomes, functional status, and assessed risk factors for requiring ECLS post-Norwood operation between January 2010 and December 2020 in a high-volume center. During the study period, 269 patients underwent a Norwood procedure of which 65 (24%) required ECLS. Of the 65 patients, 27 (41.5%) survived to hospital discharge. Mean functional status scale (FSS) score at discharge increased from 6.0 on admission to 8.48 (p < 0.0001). This change was primary in feeding (p < 0.0001) and respiratory domains (p = 0.017). Seven survivors (26%) developed new morbidity, and two (7%) developed unfavorable functional outcomes. In the regression analysis, we showed that patients with moderate-severe univentricular dysfunction on pre-Norwood transthoracic echocardiogram (odds ratio [OR] = 6.97), modified Blalock Taussig Thomas (m-BTT) shunt as source of pulmonary blood flow (OR = 2.65), moderate-severe atrioventricular valve regurgitation on transesophageal echocardiogram (OR = 8.50), longer cardiopulmonary bypass time (OR = 1.16), longer circulatory arrest time (OR = 1.20), and delayed sternal closure (OR = 3.86), had higher odds of requiring ECLS (p < 0.05). Careful identification of these risk factors is imperative to improve the care of this high-risk cohort and improve overall outcomes.

Hypoplastic Left Heart Syndrome With Low Birth Weight or Prematurity: What Is the Optimal Approach?

BACKGROUND

Hypoplastic left heart syndrome with low birth weight or prematurity comprises a high-risk population with no optimal treatment pathway. Using the Pediatric Health Information System, we compared management approaches across the United States.

METHODS

We analyzed neonates (≤30 days) with birth weight <2500 grams or gestational age <36 weeks between 2012 and 2021. Four strategies were identified: Norwood procedure, ductus arteriosus stent + pulmonary artery banding, pulmonary artery banding + prostaglandin infusion, or comfort care. Outcomes included hospital survival, discharge disposition, staged palliation completion, and 1-year transplant-free survival.

RESULTS

Of 383 infants identified, 36.4% (n = 134) received comfort care, 43.9% (n = 165) Norwood, 12.4% (n = 49) ductal stent + pulmonary artery bands, and 8.8% (n = 34) pulmonary artery bands + prostaglandins. Neonates receiving comfort care had the lowest gestational age (35 weeks; interquartile range [IQR], 31.5-37 weeks) and birth weight (2.0 kg; IQR, 1.5-2.3 kg); 24.6% (33 of 134) had chromosomal anomalies. Infants undergoing primary Norwood had the highest birth weight (2.4 kg; IQR, 2.2-2.5 kg) and gestational age (37 weeks; IQR, 35-38 weeks). Glenn palliation was performed in 66.1% (109 of 165) compared with ductal stent + pulmonary artery band in 18.4% (9 of 49) and pulmonary artery band + prostaglandins in 35.3% (12 of 34). Only 11.3% (6 of 53) born <2 kg survived to 1 year, all after Norwood. Primary Norwood yielded higher hospital and 1-year transplant-free survival than hybrid strategies.

CONCLUSIONS

Comfort care is routinely provided, particularly for infants with low birth weight, gestational age, or chromosomal anomalies. Primary Norwood offered the lowest hospital and 1-year mortality and highest palliation completion rates; birth weight was the most important factor determining 1-year survival.

High-Risk Anatomic Subsets in Hypoplastic Left Heart Syndrome

Despite overall improvements in outcomes for patients with hypoplastic left heart syndrome, there remain anatomic features that can place these patients at higher risk throughout their treatment course. These include severe preoperative obstruction to pulmonary venous return, restrictive atrial septum, coronary fistulae, severe tricuspid regurgitation, smaller ascending aorta diameter (especially if <2 mm), and poor ventricular function. The risk of traditional staged palliation has led to the development of alternative strategies for such patients. To further improve the outcomes, we must continue to diligently examine and study anatomic details in HLHS patients.

Outcomes Following Norwood Procedures: Analysis of a "Small Volume" Program

BACKGROUND

Institutional survival following Norwood procedures is traditionally correlated with a center's surgical volume. Multiple single and multi-institutional studies conducted at large-volume centers have recently demonstrated improved survival following Norwood procedures. We report both short- and long-term outcomes at a single, small-volume institution and comment on factors potentially influencing outcomes at this institution.

METHODS

All patients undergoing Norwood procedures from January 1, 2005, to January 1, 2020, at our institution were included in this study. Kaplan-Meier survival and Cox regression risk factor analyses were performed in addition to first interstage risk factor scoring to compare observed versus expected survival.

RESULTS

The cohort included 113 patients. Kaplan-Meier freedom from death or transplant was 88%, 80%, and 76% at 1, 5, and 10 years, respectively. Freedom from death following hospital discharge after Norwood procedures was 94%, 87%, and 83% at 1, 5, and 10 years, respectively. The presence of genetic syndromes was a significant risk factor for mortality. First interstage observed-to-expected mortality following discharge was 0.57 (P = .04). Postoperative length of stay was comparable to that reported for the period 2015 to 2018 in the Society of Thoracic Surgeons Database.

CONCLUSIONS

Survival outcomes at this single, small-volume institution were similar to those reported by large-volume centers and multi-institutional collaborative studies. These results may be related to structural and functional features that have been demonstrated to influence outcomes in other studies. These factors are achievable by small-volume programs with sufficient resource allocation.

Patch augmentation of small ascending aorta during stage I procedure reduces the risk of morbidity and mortality

OBJECTIVES

Hypoplastic left heart syndrome (HLHS) with aortic atresia (AA) patients are prone to coronary insufficiency due to a small ascending aorta. Prophylactic patch augmentation of the small ascending aorta during the stage I procedure (S1P) may reduce the risk of coronary insufficiency as marked by ventricular dysfunction, need for extracorporeal membrane oxygenator (ECMO) support or mortality.

METHODS

Retrospective analysis of patients with HLHS with AA who underwent an S1P was completed. Baseline ascending aorta size, right ventricular (RV) function and outcome variables of transplant-free survival, ECMO support after the stage 1 operation and RV function at the time of the bidirectional Glenn and latest follow-up were collected.

RESULTS

Between January 2010 and April 2020, 11 patients underwent prophylactic ascending aorta augmentation at the time of the S1P as a planned portion of the procedure. A total of 125 patients underwent S1P during this period as a comparison. Overall survival was 100% for the augmented group and 74% for the control group (P = 0.66). A composite end point of transplant-free survival, no post-S1P ECMO and less than moderate RV dysfunction was created. At the time of BDG, this composite end point was 100% for the augmented group and 61.8% for the control group (P = 0.008) and at most recent follow-up was 100% for the augmented group and 59.3% for control (P = 0.007). Eight patients required a rescue procedure for the clinical evidence of coronary insufficiency following S1P that included ascending aorta patch augmentation or stent placement. When comparing these rescue versus prophylactic ascending aortic augmentations, there were also differences in the composite outcome 100% for augmented and 60% for rescue (P = 0.009) and at the time of most recent follow-up 100% for augmented and 50% for rescue (P = 0.029).

CONCLUSIONS

Prophylactic patch augmentation of the ascending aorta in HLHS patients with AA may reduce the risk of mortality, ECMO and reduced RV function. Patients not initially undergoing augmentation but then requiring a rescue procedure have particularly poor outcomes. Patch augmentation for smaller ascending aortic diameters should be considered and further clinical experience may help delineate aorta diameter threshold for augmentation.

Hypoplastic left heart syndrome with anomalous origin of right pulmonary artery

Classic hypoplastic left heart syndrome is a rare but fatal congenital heart disease associated with variable underdevelopment of the left side of the heart. Complex forms of hypoplastic left heart syndrome have been reported to coexist with anomalous pulmonary venous drainage, transposition of the great arteries, or pulmonary valve dysplasia. We report a case of hypoplastic left heart syndrome with anomalous origin of the right pulmonary artery from the ascending aorta a rare association not reported in the literature. Preoperative comprehensive echocardiography is essential for diagnosis and accurate recognition of such rare anatomic variations.