Lynn Mahony

Comparison of shunt types in the Norwood procedure for single-ventricle lesions.

BACKGROUND The Norwood procedure with a modified Blalock-Taussig (MBT) shunt, the first palliative stage for single-ventricle lesions with systemic outflow obstruction, is associated with high mortality. The right ventricle-pulmonary artery (RVPA) shunt may improve coronary flow but requires a ventriculotomy. We compared the two shunts in infants with hypoplastic heart syndrome or related anomalies. METHODS Infants undergoing the Norwood procedure were randomly assigned to the MBT shunt (275 infants) or the RVPA shunt (274 infants) at 15 North American centers. The primary outcome was death or cardiac transplantation 12 months after randomization. Secondary outcomes included unintended cardiovascular interventions and right ventricular size and function at 14 months and transplantation-free survival until the last subject reached 14 months of age. RESULTS Transplantation-free survival 12 months after randomization was higher with the RVPA shunt than with the MBT shunt (74% vs. 64%, P=0.01). However, the RVPA shunt group had more unintended interventions (P=0.003) and complications (P=0.002). Right ventricular size and function at the age of 14 months and the rate of nonfatal serious adverse events at the age of 12 months were similar in the two groups. Data collected over a mean (+/-SD) follow-up period of 32+/-11 months showed a nonsignificant difference in transplantation-free survival between the two groups (P=0.06). On nonproportional-hazards analysis, the size of the treatment effect differed before and after 12 months (P=0.02). CONCLUSIONS In children undergoing the Norwood procedure, transplantation-free survival at 12 months was better with the RVPA shunt than with the MBT shunt. After 12 months, available data showed no significant difference in transplantation-free survival between the two groups. (ClinicalTrials.gov number, NCT00115934.)

Contemporary Outcomes After the Fontan Procedure: A Pediatric Heart Network Multicenter Study

OBJECTIVES We characterized a large cohort of children who had a Fontan procedure, with measures of functional health status, ventricular size and function, exercise capacity, heart rhythm, and brain natriuretic peptide (BNP). BACKGROUND The characteristics of contemporary Fontan survivors are not well described. METHODS We enrolled 546 children (age 6 to 18 years, mean 11.9 years) and compared them within pre-specified anatomic and procedure subgroups. History and outcome measures were obtained within a 3-month period. RESULTS Predominant ventricular morphology was 49% left ventricular (LV), 34% right ventricular (RV), and 19% mixed. Ejection fraction (EF) was normal for 73% of subjects; diastolic function grade was normal for 28%. Child Health Questionnaire mean summary scores were lower than for control subjects; however, over 80% of subjects were in the normal range. Brain natriuretic peptide concentration ranged from <4 to 652 pg/ml (median 13 pg/ml). Mean percent predicted peak O2 consumption was 65% and decreased with age. Ejection fraction and EF Z score were lowest, and semilunar and atrioventricular (AV) valve regurgitation were more prevalent in the RV subgroup. Older age at Fontan was associated with more severe AV valve regurgitation. Most outcomes were not associated with a superior cavopulmonary connection before Fontan. CONCLUSIONS Measures of ventricular systolic function and functional health status, although lower on average in the cohort compared with control subjects, were in the majority of subjects within 2 standard deviations of the mean for control subjects. Right ventricular morphology was associated with poorer ventricular and valvular function. Effective strategies to preserve ventricular and valvular function, particularly for patients with RV morphology, are needed.

Atenolol versus Losartan in Children and Young Adults With Marfan's Syndrome

BACKGROUND Aortic-root dissection is the leading cause of death in Marfans syndrome. Studies suggest that with regard to slowing aortic-root enlargement, losartan may be more effective than beta-blockers, the current standard therapy in most centers. METHODS We conducted a randomized trial comparing losartan with atenolol in children and young adults with Marfans syndrome. The primary outcome was the rate of aortic-root enlargement, expressed as the change in the maximum aortic-root-diameter z score indexed to body-surface area (hereafter, aortic-root z score) over a 3-year period. Secondary outcomes included the rate of change in the absolute diameter of the aortic root; the rate of change in aortic regurgitation; the time to aortic dissection, aortic-root surgery, or death; somatic growth; and the incidence of adverse events. RESULTS From January 2007 through February 2011, a total of 21 clinical centers enrolled 608 participants, 6 months to 25 years of age (mean [±SD] age, 11.5±6.5 years in the atenolol group and 11.0±6.2 years in the losartan group), who had an aortic-root z score greater than 3.0. The baseline-adjusted rate of change in the mean (±SE) aortic-root z score did not differ significantly between the atenolol group and the losartan group (-0.139±0.013 and -0.107±0.013 standard-deviation units per year, respectively; P=0.08). Both slopes were significantly less than zero, indicating a decrease in the aortic-root diameter relative to body-surface area with either treatment. The 3-year rates of aortic-root surgery, aortic dissection, death, and a composite of these events did not differ significantly between the two treatment groups. CONCLUSIONS Among children and young adults with Marfans syndrome who were randomly assigned to losartan or atenolol, we found no significant difference in the rate of aortic-root dilatation between the two treatment groups over a 3-year period. (Funded by the National Heart, Lung, and Blood Institute and others; ClinicalTrials.gov number, NCT00429364.).

Enalapril in Infants With Single Ventricle Results of a Multicenter Randomized Trial

Background— Angiotensin-converting enzyme inhibitor therapy improves clinical outcome and ventricular function in adults with heart failure. Infants with single-ventricle physiology have poor growth and are at risk for abnormalities in ventricular systolic and diastolic function. The ability of angiotensin-converting enzyme inhibitor therapy to preserve ventricular function and improve somatic growth and outcomes in these infants is unknown. Methods and Results— The Pediatric Heart Network conducted a double-blind trial involving 230 infants with single-ventricle physiology randomized to receive enalapril (target dose 0.4 mg · kg−1 · d−1) or placebo who were followed up until 14 months of age. The primary end point was weight-for-age z score at 14 months. The primary analysis was intention to treat. A total of 185 infants completed the study. There were 24 and 21 withdrawals or deaths in the enalapril and placebo groups, respectively (P=0.74). Weight-for-age z score was not different between the enalapril and placebo groups (mean±SE −0.62±0.13 versus −0.42±0.13, P=0.28). There were no significant group differences in height-for-age z score, Ross heart failure class, brain natriuretic peptide concentration, Bayley scores of infant development, or ventricular ejection fraction. The incidence of death or transplantation was 13% and did not differ between groups. Serious adverse events occurred in 88 patients in the enalapril group and 87 in the placebo group. Conclusions— Administration of enalapril to infants with single-ventricle physiology in the first year of life did not improve somatic growth, ventricular function, or heart failure severity. The results of this randomized trial do not support the routine use of enalapril in this population. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00113087.

Enalapril Does Not Enhance Exercise Capacity in Patients After Fontan Procedure

BACKGROUND Angiotensin-converting enzyme inhibitors improve exercise capacity in adults with congestive heart failure by decreasing systemic vascular resistance and improving ventricular diastolic function. Patients who have undergone the Fontan procedure have decreased cardiac output, increased systemic vascular resistance, abnormal diastolic function, and decreased exercise capacity compared with normal people. METHODS AND RESULTS To test the hypothesis that afterload reduction therapy alters hemodynamic variables and augments exercise capacity in patients after a Fontan procedure, we compared the results of graded exercise with maximal effort from 18 subjects (14.5+/-6.2 years of age, 4 to 19 years after Fontan procedure) in a randomized, double-blind, placebo-controlled crossover trial using enalapril (0.2 to 0.3 mg x kg[-1] x d[-1], maximum 15 mg). Each treatment was administered for 10 weeks. Diastolic filling patterns at rest were assessed by Doppler determination of the systemic atrioventricular valve flow velocity at the conclusion of each therapy. No difference was detected in resting heart rate, blood pressure, or cardiac index. Diastolic filling patterns were also similar. Exercise duration was not different (6.4+/-2.6 [enalapril] versus 6.7+/-2.6 minutes [placebo]). The mean percent increase in cardiac index from rest to maximum exercise was slightly but significantly decreased in subjects after 10 weeks of enalapril therapy (102+/-34% [enalapril] versus 125+/-34% [placebo]; P<.02). At maximal exercise, cardiac index (3.5+/-0.9 [enalapril] versus 3.8+/-0.9 L x min[-1] x m2 [placebo]), oxygen consumption (18.3+/-9 [enalapril] versus 20.5+/-7 mL x min[-1] x kg[-1] [placebo]), minute ventilation (57.5+/-17 [enalapril] versus 55.4+/-19 L/min [placebo]), and total work (247+/-181 [enalapril] versus 261+/-197 W [placebo]) were not different. CONCLUSIONS We conclude that enalapril administration for 10 weeks does not alter abnormal systemic vascular resistance, resting cardiac index, diastolic function, or exercise capacity in patients who have undergone a Fontan procedure.

Clinical Outcomes of Palliative Surgery Including a Systemic-to-Pulmonary Artery Shunt in Infants With Cyanotic Congenital Heart Disease Does Aspirin Make a Difference?

Background— Aspirin (ASA) often is used to prevent thrombosis in infants with congenital heart disease after placement of a systemic-to–pulmonary artery shunt, but its effect on outcomes is unknown. Methods and Results— The present multicenter study prospectively collected data on 1-year postoperative rates of death, shunt thrombosis, or hospitalization age <4 months for bidirectional Glenn/hemi-Fontan surgery in 1004 infants. The use and dose of ASA were recorded. Kaplan-Meier event rates were calculated for each event and the composite outcome, and a Cox regression model was constructed for time to event. Model terms were ASA use and type of surgery, with adjustment for age at surgery. Diagnoses were hypoplastic left heart syndrome (n=346), tricuspid atresia (n=103), tetralogy of Fallot (n=127), pulmonary atresia (n=177), heterotaxy syndrome (n=38), and other (n=213). There were 344 shunts placed without cardiopulmonary bypass (closed shunt), 287 shunts with bypass (open shunt), 323 Norwood procedures, and 50 Sano procedures. Overall, 80% of patients received ASA. One-year postoperative events rates were high: 38% for the composite end point, 26% for death, and 12% for shunt thrombosis. After the exclusion of patients with early mortality, patients receiving ASA had a lower risk of shunt thrombosis (hazard ratio, 0.13; P=0.008) and death (closed shunt: hazard ratio, 0.41, P=0.057; open shunt: hazard ratio, 0.10, P<0.001; Norwood: hazard ratio, 0.34, P<0.001; Sano: hazard ratio, 0.68, P=NS) compared with those not receiving ASA. Conclusions— The morbidity and mortality for infants after surgical placement of a systemic-to–pulmonary artery shunt are high. ASA appears to lower the risk of death and shunt thrombosis in the present observational study.

Intermediate-term mortality and cardiac transplantation in infants with single-ventricle lesions: Risk factors and their interaction with shunt type

OBJECTIVE The study objective was to identify factors associated with death and cardiac transplantation in infants undergoing the Norwood procedure and to determine differences in associations that might favor the modified Blalock-Taussig shunt or a right ventricle-to-pulmonary artery shunt. METHODS We used competing risks methodology to analyze death without transplantation, cardiac transplantation, and survival without transplantation. Parametric time-to-event modeling and bootstrapping were used to identify independent predictors. RESULTS Data from 549 subjects (follow-up, 2.7 ± 0.9 years) were analyzed. Mortality risk was characterized by early and constant phases; transplant was characterized by only a constant phase. Early phase factors associated with death included lower socioeconomic status (P = .01), obstructed pulmonary venous return (P < .001), smaller ascending aorta (P = .02), and anatomic subtype. Constant phase factors associated with death included genetic syndrome (P < .001) and lower gestational age (P < .001). The right ventricle-to-pulmonary artery shunt demonstrated better survival in the 51% of subjects who were full term with aortic atresia (P < .001). The modified Blalock-Taussig shunt was better among the 4% of subjects who were preterm with a patent aortic valve (P = .003). Lower pre-Norwood right ventricular fractional area change, pre-Norwood surgery, and anatomy other than hypoplastic left heart syndrome were independently associated with transplantation (all P < .03), but shunt type was not (P = .43). CONCLUSIONS Independent risk factors for intermediate-term mortality include lower socioeconomic status, anatomy, genetic syndrome, and lower gestational age. Term infants with aortic atresia benefited from a right ventricle-to-pulmonary artery shunt, and preterm infants with a patent aortic valve benefited from a modified Blalock-Taussig shunt. Right ventricular function and anatomy, but not shunt type, were associated with transplantation.

Design and rationale of a randomized trial comparing the Blalock-Taussig and right ventricle-pulmonary artery shunts in the Norwood procedure

OBJECTIVE The initial palliative procedure for patients born with hypoplastic left heart syndrome and related single right ventricle anomalies, the Norwood procedure, remains among the highest risk procedures in congenital heart surgery. The classic Norwood procedure provides pulmonary blood flow with a modified Blalock-Taussig shunt. Improved outcomes have been reported in a few small, nonrandomized studies of a modification of the Norwood procedure that uses a right ventricle-pulmonary artery shunt to provide pulmonary blood flow. Other nonrandomized studies have shown no differences between the two techniques. METHODS The Pediatric Heart Network designed a randomized clinical trial to compare outcomes for subjects undergoing a Norwood procedure with either the right ventricle-pulmonary artery or modified Blalock-Taussig shunt. Infants with a diagnosis of single, morphologically right ventricle anomaly who are undergoing a Norwood procedure are eligible for inclusion in this study. The primary outcome is death or cardiac transplant 12 months after random assignment. Secondary outcomes include postoperative morbidity after Norwood and stage II palliation procedures, right ventricular function and pulmonary arterial growth at stage II palliation, and neurodevelopmental outcomes at 14 months old. Incidence of adverse events will also be compared between treatment groups. CONCLUSION This study will make an important contribution to the care of patients with hypoplastic left heart syndrome and related forms of single, morphologically right ventricle. It also establishes a model with which other operative interventions for patients with congenital cardiovascular malformations can be evaluated in the future.

Validation of the Pediatric Cardiac Quality of Life Inventory

OBJECTIVE: The purpose of this multicenter study was to confirm the validity and reliability of the Pediatric Cardiac Quality of Life Inventory (PCQLI). METHODS: Seven centers recruited pediatric patients (8–18 years of age) with heart disease (HD) and their parents to complete the PCQLI and generic health-related quality of life (Pediatric Quality of Life Inventory [PedsQL]) and non–quality of life (Self-Perception Profile for Children [SPPC]/Self-Perception Profile for Adolescents [SPPA] and Youth Self-Report [YSR]/Child Behavior Checklist [CBCL]) tools. PCQLI construct validity was assessed through correlations of PCQLI scores between patients and parents and with severity of congenital HD, medical care utilization, and PedsQL, SPPC/SPPA, and YSR/CBCL scores. PCQLI test-retest reliability was evaluated. RESULTS: The study enrolled 1605 patient-parent pairs. Construct validity was substantiated by the association of lower PCQLI scores with Fontan palliation and increased numbers of cardiac operations, hospital admissions, and physician visits (P < .001); moderate to good correlations between patient and parent PCQLI scores (r = 0.41–0.61; P < .001); and fair to good correlations between PCQLI total scores and PedsQL total (r = 0.70–0.76), SPPC/SPPA global self-worth (r = 0.43–0.46), YSR/CBCL total competency (r = 0.28–0.37), and syndrome and Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition-oriented scale (r = −0.58 to −0.30; P < .001) scores. Test-retest reliability correlations were excellent (r = 0.78–0.90; P < .001). CONCLUSIONS: PCQLI scores are valid and reliable for children and adolescents with congenital and acquired HD and may be useful for future research and clinical management.

BNP Levels Predict Outcome in Pediatric Heart Failure Patients: Post-hoc Analysis of the Pediatric Carvedilol Trial

Background— The ability of serum B-type natriuretic peptide levels (BNP) to predict outcomes in children with heart failure (HF) has not been well demonstrated. This study was designed to determine whether BNP levels predict outcomes in patients with moderate symptomatic HF. Methods and Results— We investigated whether enrollment BNP levels for the Pediatric Carvedilol Trial were associated with baseline characteristics. Freedom from a composite end point of HF hospitalization, death, or transplantation at 9 months was compared using a threshold BNP level identified using receiver operating curve analysis. Median BNP level was 110 pg/mL (interquartile range, 22.4 to 342.0 pg/mL) in 138 subjects. Median age was 3.4 years (interquartile range, 1.1 to 11.0 years). Diagnoses were cardiomyopathy (60%) and congenital heart disease (40%); 73% had a systemic left ventricle. BNP levels correlated moderately with left ventricular ejection fraction ( R =0.39, P 2 years (hazard ratio, 4.45; 95% confidence interval, 1.68 to 12.04; P =0.003) were independently associated with worse outcomes. Conclusions— In children with moderately symptomatic HF, BNP ≥140 pg/mL and age >2 years identified subjects at higher risk for worse outcome. Further validation is needed to determine the BNP levels necessary to stratify risk in other pediatric cohorts.Background—The ability of serum B-type natriuretic peptide levels (BNP) to predict outcomes in children with heart failure (HF) has not been well demonstrated. This study was designed to determine whether BNP levels predict outcomes in patients with moderate symptomatic HF. Methods and Results—We investigated whether enrollment BNP levels for the Pediatric Carvedilol Trial were associated with baseline characteristics. Freedom from a composite end point of HF hospitalization, death, or transplantation at 9 months was compared using a threshold BNP level identified using receiver operating curve analysis. Median BNP level was 110 pg/mL (interquartile range, 22.4 to 342.0 pg/mL) in 138 subjects. Median age was 3.4 years (interquartile range, 1.1 to 11.0 years). Diagnoses were cardiomyopathy (60%) and congenital heart disease (40%); 73% had a systemic left ventricle. BNP levels correlated moderately with left ventricular ejection fraction (R=0.39, P<0.001) but did not differ by HF class, age, diagnosis, sex, ventricular morphology, or left ventricular end-diastolic dimension Z-score (R=0.19). Outcome events included 25 HF hospitalizations, 4 deaths, and 2 transplants. Sensitivity was 71% and specificity 63%, for a BNP cutoff value of 140 pg/mL. BNP ≥140 pg/mL (hazard ratio, 3.7; 95% confidence interval, 1.62 to 8.4; P=0.002) and age >2 years (hazard ratio, 4.45; 95% confidence interval, 1.68 to 12.04; P=0.003) were independently associated with worse outcomes. Conclusions—In children with moderately symptomatic HF, BNP ≥140 pg/mL and age >2 years identified subjects at higher risk for worse outcome. Further validation is needed to determine the BNP levels necessary to stratify risk in other pediatric cohorts.