Shaji C. Menon

Early Developmental Outcome in Children With Hypoplastic Left Heart Syndrome and Related Anomalies The Single Ventricle Reconstruction Trial

Background— Survivors of the Norwood procedure may experience neurodevelopmental impairment. Clinical trials to improve outcomes have focused primarily on methods of vital organ support during cardiopulmonary bypass. Methods and Results— In the Single Ventricle Reconstruction trial of the Norwood procedure with modified Blalock-Taussig shunt versus right-ventricle-to-pulmonary-artery shunt, 14-month neurodevelopmental outcome was assessed by use of the Psychomotor Development Index (PDI) and Mental Development Index (MDI) of the Bayley Scales of Infant Development-II. We used multivariable regression to identify risk factors for adverse outcome. Among 373 transplant-free survivors, 321 (86%) returned at age 14.3±1.1 (mean±SD) months. Mean PDI (74±19) and MDI (89±18) scores were lower than normative means (each P<0.001). Neither PDI nor MDI score was associated with type of Norwood shunt. Independent predictors of lower PDI score (R2=26%) were clinical center (P=0.003), birth weight <2.5 kg (P=0.023), longer Norwood hospitalization (P<0.001), and more complications between Norwood procedure discharge and age 12 months (P<0.001). Independent risk factors for lower MDI score (R2=34%) included center (P<0.001), birth weight <2.5 kg (P=0.04), genetic syndrome/anomalies (P=0.04), lower maternal education (P=0.04), longer mechanical ventilation after the Norwood procedure (P<0.001), and more complications after Norwood discharge to age 12 months (P<0.001). We found no significant relationship of PDI or MDI score to perfusion type, other aspects of vital organ support (eg, hematocrit, pH strategy), or cardiac anatomy. Conclusions— Neurodevelopmental impairment in Norwood survivors is more highly associated with innate patient factors and overall morbidity in the first year than with intraoperative management strategies. Improved outcomes are likely to require interventions that occur outside the operating room. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00115934.

Neurodevelopmental Outcomes After Cardiac Surgery in Infancy

BACKGROUND: Neurodevelopmental disability is the most common complication for survivors of surgery for congenital heart disease (CHD). METHODS: We analyzed individual participant data from studies of children evaluated with the Bayley Scales of Infant Development, second edition, after cardiac surgery between 1996 and 2009. The primary outcome was Psychomotor Development Index (PDI), and the secondary outcome was Mental Development Index (MDI). RESULTS: Among 1770 subjects from 22 institutions, assessed at age 14.5 ± 3.7 months, PDIs and MDIs (77.6 ± 18.8 and 88.2 ± 16.7, respectively) were lower than normative means (each P < .001). Later calendar year of birth was associated with an increased proportion of high-risk infants (complexity of CHD and prevalence of genetic/extracardiac anomalies). After adjustment for center and type of CHD, later year of birth was not significantly associated with better PDI or MDI. Risk factors for lower PDI were lower birth weight, white race, and presence of a genetic/extracardiac anomaly (all P ≤ .01). After adjustment for these factors, PDIs improved over time (0.39 points/year, 95% confidence interval 0.01 to 0.78; P = .045). Risk factors for lower MDI were lower birth weight, male gender, less maternal education, and presence of a genetic/extracardiac anomaly (all P < .001). After adjustment for these factors, MDIs improved over time (0.38 points/year, 95% confidence interval 0.05 to 0.71; P = .02). CONCLUSIONS: Early neurodevelopmental outcomes for survivors of cardiac surgery in infancy have improved modestly over time, but only after adjustment for innate patient risk factors. As more high-risk CHD infants undergo cardiac surgery and survive, a growing population will require significant societal resources.

Cardiac troponin T mutation in familial cardiomyopathy with variable remodeling and restrictive physiology

We identified a unique family with autosomal dominant heart disease variably expressed as restrictive cardiomyopathy (RCM), hypertrophic cardiomyopathy (HCM), and dilated cardiomyopathy (DCM), and sought to identify the molecular defect that triggered divergent remodeling pathways. Polymorphic DNA markers for nine sarcomeric genes for DCM and/or HCM were tested for segregation with disease. Linkage to eight genes was excluded, but a cardiac troponin T (TNNT2) marker cosegregated with the disease phenotype. Sequencing of TNNT2 identified a heterozygous missense mutation resulting in an I79N substitution, inherited by all nine affected family members but by none of the six unaffected relatives. Mutation carriers were diagnosed with RCM (n = 2), non‐obstructive HCM (n = 3), DCM (n = 2), mixed cardiomyopathy (n = 1), and mild concentric left ventricular hypertrophy (n = 1). Endomyocardial biopsy in the proband revealed non‐specific fibrosis, myocyte hypertrophy, and no myofibrillar disarray. Restrictive Doppler filling patterns, atrial enlargement, and pulmonary hypertension were observed among family members regardless of cardiomyopathy subtype. Mutation of a sarcomeric protein gene can cause RCM, HCM, and DCM within the same family, underscoring the necessity of comprehensive morphological and physiological cardiac assessment in familial cardiomyopathy screening.

Regional myocardial dysfunction following Norwood with right ventricle to pulmonary artery conduit in patients with hypoplastic left heart syndrome.

BACKGROUND Improved early survival has led many centers to use the right ventricle-to-pulmonary artery (RVPA) conduit instead of the modified Blalock-Taussig shunt for Norwood palliation of hypoplastic left-heart syndrome. However, there is concern regarding the potential deleterious effects of the required right ventriculotomy for placement of the RVPA conduit on global and regional right ventricular (RV) function. The purpose of this study was to investigate global and regional RV wall motion abnormalities after Norwood palliation with RVPA conduit using Velocity Vector Imaging (VVI). METHODS Thirty consecutive patients with hypoplastic left-heart syndrome who underwent stage 2 palliation between January 2007 and December 2009 were identified from the surgical database. VVI was performed on two-dimensional echocardiographic images obtained before second-stage palliation. Peak systolic circumferential and radial velocity, strain, and strain rate were measured from parasternal short-axis and apical four-chamber views. RV ejection fraction was measured using the biplane modified Simpsons rule. Regional RV systolic deformations were compared between different RV segments. VVI measures were also compared with RV systolic function. In a subgroup (n = 14), VVI was repeated on follow-up after stage 2 palliation to evaluate changes in regional and global RV deformation. RESULTS A total of 30 patients (20 males) were studied. The median age at the time of interstage echocardiography was 12 weeks (range, 8-18 weeks). In the short axis, average peak systolic circumferential strain values for the anterior, posterior, septal, and RV free wall segments were 3.79 ± 2.52%, 11.4 ± 5.2%, 13.3 ± 6.5%, and 11.1 ± 5.0%, respectively. From the short-axis view, the anterior RV segment (ventriculotomy site) exhibited significantly reduced circumferential velocity, peak systolic strain, and strain rate (P < .0001). Mean global VVI measurements were correlated with RV ejection fraction. On follow-up after stage 2 palliation, the ventriculotomy region showed persistently reduced velocity, peak systolic strain, and strain rate compared with all other segments. CONCLUSIONS In patients with hypoplastic left-heart syndrome after Norwood palliation with RVPA conduit, RV myocardial deformation was significantly reduced at the ventriculotomy site, which persisted after stage 2 palliation. VVI-derived measures demonstrating impairment of global systolic myocardial deformation were correlated with RV systolic function. Long-term multicenter studies to evaluate the effects of ventriculotomy scar on single systemic right ventricle are required.

Impact of operative and postoperative factors on neurodevelopmental outcomes after cardiac operations

BACKGROUND Neurodevelopmental disability is common after operations for congenital heart defects. We previously showed that patient and preoperative factors, center, and calendar year of birth explained less than 30% of the variance for the Psychomotor Development Index (PDI) and the Mental Development Index (MDI) of the Bayley Scales of Infant Development-Second Edition. Here we investigate how much additional variance in PDI and MDI is contributed by operative variables and postoperative events. METHODS We analyzed neurodevelopmental outcomes after operations with cardiopulmonary bypass at age 9 months or younger between 1996 and 2009. We used linear regression to investigate the effect of operative factors (age, weight, and cardiopulmonary bypass variables) and postoperative events on neurodevelopmental outcomes, adjusting for center, type of congenital heart defect, year of birth, and preoperative factors. RESULTS We analyzed 1,770 children from 22 institutions with neurodevelopmental testing at age 13.3 months (range, 6 to 30 months). Among operative factors, longer total support time was associated with lower PDI and MDI (p < 0.05). When postoperative events were added, use of either extracorporeal membrane oxygenation or ventricular assist device support, and longer postoperative length of stay were associated with lower PDI and MDI (p < 0.05). Longer total support time was not a significant predictor in these models. After adjusting for patient, preoperative, intraoperative, and postoperative factors, measured intraoperative and postoperative factors accounted for 5% of the variances in PDI and MDI. CONCLUSIONS Operative factors may be less important than innate patient and preoperative factors and postoperative events in predicting early neurodevelopmental outcomes after cardiac operations in infants. Neurodevelopmental outcomes improved over calendar time when adjusted for patient and medical variables.

Diastolic Dysfunction and Its Histopathological Correlation in Obstructive Hypertrophic Cardiomyopathy in Children and Adolescents

BACKGROUND Histopathologic hallmarks of hypertrophic cardiomyopathy (HCM) include myocyte hypertrophy and disarray as well as interstitial and endocardial fibrosis. Published correlations between echocardiographic parameters and histopathologic findings are scarce. METHODS All patients aged <20 years (n = 45; 15 female patients; median age, 14 years) with obstructive HCM undergoing septal myectomy at the Mayo Clinic from 2003 to 2007 were identified. A retrospective review of echocardiographic data was performed, and these data were compared with the histologic findings from the myectomy specimens. RESULTS Histopathologic analysis of myectomy specimens revealed significant myocyte hypertrophy (100%), myocyte disarray (98%), interstitial fibrosis (95%), and subendocardial fibrosis (97%). On multivariate regression analysis, there was a significant relationship between the degree of myocyte disarray and echocardiographic markers of left ventricular diastolic dysfunction. CONCLUSION The results of this study suggest that myocyte disarray is a key factor responsible for diastolic dysfunction in pediatric patients with obstructive HCM. These findings provide novel insights into the mechanism of diastolic dysfunction in HCM that warrant further study.

Myocardial strain and strain rate in Kawasaki disease

AIMS We sought to determine whether velocity vector imaging (VVI)-derived left ventricular (LV) myocardial deformation indices could detect subtle myocardial abnormalities in acute Kawasaki disease (KD). METHODS AND RESULTS The study cohort of children with KD was divided by coronary artery dilation (CAD, Z-score >2.5) and/or uncomplicated vs. treatment-resistant (persistent/recrudescent fever) cases and compared with age-matched controls. Peak systolic LV myocardial strain (ε) and strain rate (SR) were obtained using VVI on pre-treatment echocardiograms. Comparisons were made between controls and (i) the entire KD group, (ii) KD group subdivided by CAD, and (iii) KD group subdivided by treatment resistance. The KD group consisted of 32 children (66% male, 24 ± 20 months). Of these, 17 had CAD and 14 had resistant KD. The control group consisted of 22 children (55% male, 20 ± 17 months). Routine echo indices of LV systolic function were normal for both groups. Compared with controls, KD patients had lower global longitudinal ε (-15.29 vs. -12.94, P = 0.04) and SR (-1.12 vs. -0.87, P = 0.003). On subgroup analysis compared with controls, KD patients with CAD (n = 17) had lower longitudinal ε (-15.29 vs. -11.87, P = 0.02) and SR (-1.12 vs. -0.86, P = 0.005). Subdivided by treatment resistance, compared with controls, those with resistant KD had lower longitudinal ε (-15.29 vs. -11.8, P = 0.01) and SR (-1.12 vs. -0.82, P = 0.003). CONCLUSION Despite normal LV systolic function by routine echocardiographic measurements, KD patients have reduced longitudinal LV ε and SR, which may be more sensitive indicators of myocardial inflammation and may provide supportive criteria to avoid delayed diagnosis of KD.

Regional and global myocardial deformation of the fetal right ventricle in hypoplastic left heart syndrome

Quantification of fetal right ventricular (RV) function by 2D‐echocardiography is challenging. Velocity vector imaging (VVI) is an angle independent speckle tracking technique that assesses regional myocardial mechanics. Alteration in the deformation of the fetal RV in hypoplastic left heart syndrome (HLHS) is unknown. This study aimed to evaluate the regional mechanics of the fetal RV in HLHS.

Long-term outcome after atrioventricular valve surgery following modified Fontan operation

OBJECTIVE The objective of this study was to evaluate the early and late results of atrioventricular valve surgery after Fontan operation. BACKGROUND Atrioventricular valve regurgitation is a known perioperative risk factor for Fontan operation. There are limited data on the outcomes of late atrioventricular valve surgery following Fontan operation. METHODS Patients who underwent atrioventricular valve surgery following Fontan procedure were identified from the Mayo Clinic Fontan database. Medical records were reviewed for pre-operative, operative, and post-operative clinical and haemodynamic data. All patients not known to be deceased were sent health status questionnaires. RESULTS A total of 61 patients (28 females) underwent atrioventricular valve surgery following Fontan procedure. The median age at atrioventricular valve surgery was 14 years. The median duration between Fontan and atrioventricular valve surgery was 4.7 years. Median follow-up was 9 years. There were a total of 32 (52%) deaths with 8 (13%) within 30 days of surgery. The 5-, 10-, and 15-year survival rates were 67%, 57%, and 45%, respectively. On follow-up, 44 of 61 (72%) had arrhythmias, 21 of 29 (72%) were symptomatic, and 12 of 61 (20%) developed protein-losing enteropathy. On multivariate analysis, reduced ventricular function and development of protein-losing enteropathy were associated with decreased survival. CONCLUSION Atrioventricular valve surgery after Fontan procedure is associated with substantial late morbidity and mortality. Atrioventricular valve surgery in this cohort of patients portends poor long-term outcome and is associated with a high incidence of protein-losing enteropathy. Reduced ventricular function and development of protein-losing enteropathy were associated with decreased survival.

Hamartomas of mature cardiac myocytes: report of 7 new cases and review of literature

Only 8 cases of hamartomas of mature cardiac myocytes have been reported. The aim of the study was to describe 7 new cases and provide clinicopathologic correlation. Our anatomical pathology database was searched for all cases of cardiac hamartoma, of which 7 represented mature myocyte type. Medical records were reviewed for clinical information, and microscopic slides were evaluated for extent of characteristics. Five males and 2 females ranged in age from 6 months to 74 years (mean, 23 years). There were 11 ventricular hamartomas (8 left free wall, 2 right free wall, 1 septum). Death in 3 infants was unrelated to incidental hamartomas discovered at autopsy. A 10- and 16-year-old were asymptomatic but had abnormal electrocardiogram (ECG) results, which led to detection of cardiac masses by imaging studies. Two adult males had only mild coronary disease angiographically. The 57-year-old, who died suddenly, had a 7-year history of abnormal ECG results. The 74-year-old, who died after aortic surgery, had a 3-year history of chest discomfort. Their hamartomas were identified at autopsy and contributed to sudden death in 1. Microscopically, all hamartomas were involved by myocyte hypertrophy and disarray, without inflammation or calcification. Myocyte vacuolization and venular dilatation occurred only in the pediatric cases, and interstitial adipose tissue only affected 1 adult. In conclusion, hamartomas of mature cardiac myocytes may be detected at any age. They primarily affect males, arise predominantly in the left ventricle, are asymptomatic, may have nonspecific ECG findings, and rarely may be associated with sudden death. Microscopic findings in infants differ from older patients.