Hypoplastic left heart syndrome and aortic atresia-mitral stenosis variant: role of myocardial protection strategy and impact of ventriculo-coronary connections after stage I palliation

Ventriculocoronary connection with mitral stenosis/aortic stenosis hypoplastic left heart: a case report

Ventriculocoronary connections develop most commonly in children with mitral stenosis/aortic atresia hypoplastic left heart. These connections can lead to myocardial ischaemia and dysfunction. We report a newborn with mitral stenosis/aortic stenosis hypoplastic left heart who endured systemic ventricular injury post-Norwood, secondary to a large ventriculocoronary fistula. He was treated medically and had favourable outcomes following bidirectional Glenn procedure.

Off-label uses of the Amplatzer Piccolo Occluder in children with congenital and acquired heart diseases

Aim: The Amplatzer Piccolo Occluder (APO) is approved for patent ductus arteriosus (PDA) occlusion in infants weighing >700 g but could offer versatility to treat other lesions.Methods: Retrospective review of children in whom APO was utilized for defects other than PDA between January 2022 and June 2023.Results: The APO was used in nine patients; three for ventricular septal defects, four with coronary fistulas, one for a ventricular pseudoaneurysm and one where APO deployed within a fenestration of a previously placed Amplatzer Septal Occluder. All nine patients had successful occlusions without complications.Conclusion: The APO is a versatile device that can be used to treat various small diameter lesions in children besides the PDA for which it is currently approved for.

Patent Ductus Arteriosus Occlusion in Premature Infants

Transcatheter ductal closure has proven to be safe and effective to occlude the patent ductus arteriosus (PDA) in premature infants. We have developed a robust multidisciplinary PDA program. After gaining experience performing transcatheter ductal closure in the cardiac catheterization laboratory, we transitioned to performing the procedure at the patient's bedside in the neonatal intensive care unit using echocardiographic guidance. The bedside approach has the potential to expand this therapy to patients who currently undergo expectant PDA management because of lack of availability of this therapy, and allow for earlier referral, which will reduce time of exposure to this pathologic shunt.

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.

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.

Impact of Left Ventricular Morphology on Adverse Outcomes Following Stage 1 Palliation for Hypoplastic Left Heart Syndrome: 20 Years of National Data From Sweden

Background

Hypoplastic left heart syndrome is associated with significant morbidity and mortality. We aimed to assess the influence of left ventricular morphology and choice of shunt on adverse outcome in patients with hypoplastic left heart syndrome and stage 1 palliation.

Methods and Results

This was a retrospective analysis of patients with hypoplastic left heart syndrome with stage 1 palliation between 1999 and 2018 in Sweden. Patients (n=167) were grouped based on the anatomic subtypes aortic‐mitral atresia, aortic atresia‐mitral stenosis (AA‐MS), and aortic‐mitral stenosis. The left ventricular phenotypes including globular left ventricle (Glob‐LV), miniaturized and slit‐like left ventricle (LV), and the incidence of major adverse events (MAEs) including mortality were assessed. The overall mortality and MAEs were 31% and 41%, respectively. AA‐MS (35%) was associated with both mortality (all other subtypes versus AA‐MS: interstage‐I: hazard ratio [HR], 2.7; P =0.006; overall: HR, 2.2; P =0.005) and MAEs (HR, 2.4; P =0.0009). Glob‐LV (57%), noticed in all patients with AA‐MS, 61% of patients with aortic stenosis‐mitral stenosis, and 19% of patients with aortic atresia‐mitral atresia, was associated with both mortality (all other left ventricular phenotypes versus Glob‐LV: interstage‐I: HR, 4.5; P =0.004; overall: HR, 3.4; P =0.0007) and MAEs (HR, 2.7; P =0.0007). There was no difference in mortality and MAEs between patients with AA‐MS and without AA‐MS with Glob‐LV ( P >0.15). Patients with AA‐MS (35%) or Glob‐LV (38%) palliated with a Blalock‐Taussig shunt had higher overall mortality compared with those palliated with Sano shunts, irrespective of the stage 1 palliation year (AA‐MS: HR, 2.6; P =0.04; Glob‐ LV: HR, 2.1; P =0.03).

Conclusions

Glob‐LV and AA‐MS are independent morphological risk factors for adverse short‐ and long‐ term outcome, especially if a Blalock‐Taussig shunt is used as part of stage 1 palliation. These findings are important for the clinical management of patients with hypoplastic left heart syndrome.

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.

Heart Transplantation of a Preterm Infant With HLHS

A 33-week gestation, 1.75-kg female infant with mitral stenosis/aortic atresia variant of hypoplastic left heart syndrome and severe ventriculo-coronary connections underwent surgical septectomy and bilateral pulmonary artery banding at five weeks of age (2.10 kg). After separation from bypass, she developed hemodynamic instability requiring venoarterial extracorporeal membrane oxygenation support. She was listed for heart transplantation and transplanted after three days of support with an oversized heart (4.7:1 donor-recipient weight ratio).

Ventriculocoronary Fistulas with Hypoplastic Left Heart in a Neonate: Imaging with Cardiac CT

Fistulous communications between the ventricular cavities and the coronary arterial tree can be found in the presence of hypoplasia of the left ventricle, especially when the ventricular septum is intact and mitral stenosis and aortic atresia subtype are present. The cardiac CT provides excellent anatomic information especially in the evaluation of extracardiac vessels and coronary arteries. In this case study, we report a newborn with ventriculocoronary fistulas (VCFs) with the hypoplastic left disease diagnosed with cardiac CT. Transthoracic echocardiography of a term baby showed hypoplastic left heart syndrome (HLHS) with mitral stenosis and aortic atresia. The patient immediately underwent a Sano variation of the Norwood procedure. On the postoperative second day, the clinical status of the patient deteriorated. A prospective electrocardiogram-gated axial technique was performed within a single heartbeat for the patient and large VCFs were detected and a second operation were performed to close the VCFs that failed. On the nineteenth day after the operation, the baby passed away. According to us, cardiac CT can also be performed free-breathing and without anesthesia in the neonatal period for the definition of complex cardiac anatomy with the lower radiation dose from the latest scanners, radiation risk of CT should be weighed against the anesthesia risk of cardiac MRI and intraoperative risk of conventional cardiac angiography. Pre-operative cardiac CT may increase surgical success.

Association of left ventricular size with regional right ventricular mechanics in Hypoplastic Left Heart Syndrome

BACKGROUND

In Hypoplastic Left Heart Syndrome (HLHS), RV dysfunction is associated with poor outcomes. However, the effect of varying LV size on regional RV mechanics and outcome has not been studied.

METHODS

Twenty newborns (0-7 days) with HLHS had pre-stage 1 and pre-stage 2 echocardiograms prospectively protocoled for strain analysis of the apical 4-chamber view. RV longitudinal strain was analyzed, and LV size was classified as diminutive (no visible LV chamber) or moderate size (visible LV chamber). Clinical outcome was reported as alive vs death or transplant (D-TP) at final clinical follow-up (pre-stage 3). Groups were compared with t-test, Fisher's Exact, and ANOVA tests as appropriate.

RESULTS

At pre-stage 1, infants with a diminutive LV (7/20, 35%) vs a moderately hypoplastic LV (13/20, 65%) did not have significantly different global RV strain (-18.4 ± 2.6% vs -18.8 ± 3.2%; p = 0.83). However, basal septal strain was significantly diminished in the moderately hypoplastic LV group vs the diminutive LV group (-4.4 ± 6.0% vs -14.7 ± 3.3%; p < 0.005). There was severely diminished septal strain in nearly all (11/13) of the moderately hypoplastic group. At the pre-stage II echo, global RV strain between groups remained similar (p = 0.76) as did the diminished septal strain in the moderate LV group (p = 0.86). The moderately hypoplastic LV group had worse clinical outcomes (6/13 D-TP vs 0/7 D-TP; p = 0.05).

CONCLUSIONS

In this small HLHS cohort, diminished septal strain leading to asymmetric RV mechanics may be associated with poor outcomes in those with larger LV/septal size.

Outcome of Norwood operation for hypoplastic left heart syndrome

PURPOSE

The Norwood procedure, the first surgical step of staged palliation for hypoplastic left heart syndrome (HLHS), is also applied for other complex single ventricle lesions. This study aimed to evaluate the outcome of the Norwood operation in a single center over 4 years and to identify clinical and anatomic risk factors for overall mortality.

METHODS

A retrospective review of the pediatric cardiovascular surgery database was performed to identify infants with HLHS who underwent NP (Norwood procedure) at our institution between January 2007 and December 2011. Our study population consisted of 85 patients with HLHS.

RESULTS

Early mortality (30 days postoperative period) between January 2007 and December 2011 for Norwood operation was 7 (8.2%) out of 85 patient, and overall mortality was 24 (28.2%).

CONCLUSION

Our single-center experience shows that the Norwood operation can be performed for complex single ventricle lesions with similarly good early outcomes regardless of the underlying anatomy.

Blood Versus Crystalloid Cardioplegia in Pediatric Cardiac Surgery: A Systematic Review and Meta-analysis

The benefit of blood cardioplegia (BCP) compared to crystalloid cardioplegia (CCP) is still debatable. Our aim was to systematically review and synthesize all available evidence on the use of BCP and CCP to assess if any modality provides superior outcomes in pediatric cardiac surgery. A systematic literature search of the PubMed and Cochrane databases was performed with respect to the PRISMA statement (end-of-search date: January 30th, 2017). We extracted data on study design, demographics, cardioplegia regimens, and perioperative outcomes as well as relevant biochemical markers, namely cardiac troponin I (cTnI), lactate, and ATP levels at baseline, after reperfusion and postoperatively at 1, 4, 12, and 24 h as applicable. Data were appropriately pooled using random and mixed effects models. Our systematic review includes 56 studies reporting on a total of 7711 pediatric patients. A meta-analysis of the 10 eligible studies directly comparing BCP (n = 416) to CCP (n = 281) was also performed. There was no significant difference between the two groups with regard to cTnI and Lac at any measured time point, ATP levels after reperfusion, length of intensive care unit stay (WMD: -0.08, 95% CI -1.52 to 1.36), length of hospital stay (WMD: 0.13, 95% CI -0.85 to 1.12), and 30-day mortality (OR 1.11, 95% CI 0.43-2.88). Only cTnI levels at 4 h postoperatively were significantly lower with BCP (WMD: -1.62, 95% CI -2.07 to -1.18). Based on the available data, neither cardioplegia modality seems to be superior in terms of clinical outcomes, ischemia severity, and overall functional recovery.

Cavopulmonary Anastomosis During Same Hospitalization as Stage 1 Norwood/Hybrid Palliative Surgery

BACKGROUND

Limited literature has examined characteristics of infants with hypoplastic left heart syndrome (HLHS) who remain hospitalized during the interstage period. We described their epidemiologic characteristics, in-hospital outcomes, and identified risk factors that predict the need for superior cavopulmonary anastomosis (SCPA) during the same hospitalization.

METHODS

This retrospective multicenter database analysis included infants with HLHS who underwent stage 1 palliation from 2004 through 2013.

RESULTS

Among 5374 infants with HLHS, 314 (5.8%) underwent SCPA during the same hospitalization as stage 1 palliation. They had a higher incidence of baseline comorbidities, complications, and interventions than infants who were discharged. Despite an overall increase in need for SCPA in the same hospitalization across different eras, there was no significant statistical difference in mortality in the two groups in the same era. Septicemia, necrotizing enterocolitis, modified Blalock-Taussig shunt, cardiac catheterization, cardiopulmonary resuscitation, extracorporeal membrane oxygenation, gastrostomy tube, and antiarrhythmic agents were independently associated with increased odds of undergoing SCPA during the same hospitalization. Patients undergoing right ventricle to pulmonary artery shunt were less likely to remain hospitalized until stage 2 palliation. Nonsurvivors in the SCPA group had greater need for interventions and worse intensive care unit outcomes.

CONCLUSIONS

Infants with HLHS who remain hospitalized after stage 1 until their stage 2 palliation differ significantly from infants who were discharged. Several clinical characteristics, comorbidities, and need for interventions are associated with the likelihood for undergoing stage 2 palliation during the same hospitalization. Timely identification and intervention of adjustable causes of heart failure may improve outcomes.

Hybrid Palliation for Ductal-Dependent Systemic Circulation

We reviewed our hybrid palliation experience for 91 neonates, with ductal-dependent systemic circulation, born between August 2007 and October 2015. For analysis, we stratified the 91 patients by a risk factor (RF) score and divided them into three groups: (1) high-risk two-functional ventricles (2V) median RF score of 3 (N = 20); (2) low-risk one-functional ventricle (1V) RF score 0-1 (N = 32); and (3) high-risk 1V RF score ≥2 (N = 39). Midterm survival (median 4 years) by group was: (1) 95 %, (2) 91 %, and (3) 15 %, (p = 0.001). In conclusion, hybrid palliation was associated with excellent midterm results for high-risk 2V and low-risk 1V patients with ductal-dependent systemic circulation. In contrast, high-risk 1V patients had significantly worse outcomes.

Fate of ventricular and valve performance following early bidirectional Glenn procedure after Norwood operation controlled for hypoplastic left heart syndome anatomic subtype

The Norwood operation (NO) with a right ventricle (RV)-to-pulmonary artery (PA) shunt (NRVPA) is reportedly associated with early hemodynamic advantage. Shunt strategy has been implicated in ventricular function. Outcomes after NRVPA compared with classic procedure as part of a strategy involving early bidirectional Glenn (BDG) procedure were analyzed with reference to RV, tricuspid, and neoaortic valve performance. Between January 2005 and December 2010, 128 neonates with hypoplastic left heart syndrome (HLHS) underwent NO. Controlled for aortic/mitral stenosis (AS-MS) subtype, 28 patients underwent NRVPA (group A), and 26 patients had classic procedure (group B). The patients with a non-HLHS single-ventricle anatomy and those who had undergone a hybrid approach for HLHS were excluded from the study. The mean age at NO was 6.8 ± 3.5 days in group A and 6.9 ± 3.6 days in group B. Transthoracic echocardiographic evaluation (TTE) after NO (TTE-1) at the midinterval between NO and BDG (TTE-2), before BDG (TTE-3), before Fontan (TTE-4), and at the last follow-up evaluation (TTE-5) was undertaken. Cardiac catheterization was used to assess hemodynamic parameters before the Glenn and Fontan procedures. The operative, interstage, and pre-Fontan survival rates for AS-MS after NO were respectively 88.1 % (90.3 % in group A vs. 84.7 % in group B; p = 0.08), 82.5 % (82.7 % in group A vs. 81.8 % in group B; p = 0.9), and 80.7 % (79.5 % in group A vs. 81.8 % in group B; p = 0.9). The median follow-up period was 39.6 months (interquartile range 2.7-4.9 months). The RV global function, mid- and longitudinal indexed dimensions, fractionated area change before BDG (TTE-1, TTE-2, TTE-3) and after BDG (TTE-4, TTE-5), and right ventricular end-diastolic pressure did not differ statistically between the groups (p > 0.05). No statistically significant difference in tricuspid or neoaortic intervention was found between the groups (p > 0.05). Controlled for the AS-MS HLHS subtype, shunt strategy showed no midterm survival or hemodynamic (ventricular or valve) impact. At midterm, the follow-up need for neoaortic or tricuspid valve surgical intervention was not affected by shunt selection. The structural ventricular adaptation after reversal of shunt physiology was irrespective of shunt strategy.

Individualized approach in the management of patients with hypoplastic left heart syndrome (HLHS)

Over the past decade new variations on the "classic" first stage palliation (the Norwood/BT shunt) for patients with Hypoplastic Left Heart Syndrome have emerged and been vetted by the medical community. A "one size fits all" approach may not be adequate anymore. In this review, the optimal indications for the various palliative options (Norwood/BT shunt, Norwood/RV-PA conduit, Hybrid Stage I with or without ductal stenting, heart transplantation) are reviewed from a standpoint of the initial anatomy and physiology of the patient, letting it guide clinical management. Current knowledge useful for decision-making is also reviewed as objectively as possible.

Interstage mortality after the Norwood procedure: Results of the multicenter Single Ventricle Reconstruction trial

OBJECTIVE

For infants with single ventricle malformations undergoing staged repair, interstage mortality is reported at 2% to 20%. The Single Ventricle Reconstruction trial randomized subjects with a single morphologic right ventricle undergoing a Norwood procedure to a modified Blalock-Taussig shunt (MBTS) or a right ventricle-to-pulmonary artery shunt (RVPAS). The aim of this analysis was to explore the associations of interstage mortality and shunt type, and demographic, anatomic, and perioperative factors.

METHODS

Participants in the Single Ventricle Reconstruction trial who survived to discharge after the Norwood procedure were included (n = 426). Interstage mortality was defined as death postdischarge after the Norwood procedure and before the stage II procedure. Univariate analysis and multivariable logistic regression were performed adjusting for site.

RESULTS

Overall interstage mortality was 50 of 426 (12%)-13 of 225 (6%) for RVPAS and 37 of 201 (18%) for MBTS (odds ratio [OR] for MBTS, 3.4; P < .001). When moderate to severe postoperative atrioventricular valve regurgitation (AVVR) was present, interstage mortality was similar between shunt types. Interstage mortality was independently associated with gestational age less than 37 weeks (OR, 3.9; P = .008), Hispanic ethnicity (OR, 2.6; P = .04), aortic atresia/mitral atresia (OR, 2.3; P = .03), greater number of post-Norwood complications (OR, 1.2; P = .006), census block poverty level (P = .003), and MBTS in subjects with no or mild postoperative AVVR (OR, 9.7; P < .001).

CONCLUSIONS

Interstage mortality remains high at 12% and is increased with the MBTS compared with the RVPAS if postoperative AVVR is absent or mild. Preterm delivery, anatomic, and socioeconomic factors are also important. Avoiding preterm delivery when possible and close surveillance after Norwood hospitalization for infants with identified risk factors may reduce interstage mortality.