Abnormal Longitudinal Growth of the Aorta in Children with Familial Bicuspid Aortic Valve.

Bicuspid aortic valve (BAV) is the most common type of congenital heart defect (CHD) and is associated with clinically significant cardiovascular complications including valve calcification and ascending aortopathy (AscAo), predominantly occurring in adulthood. While a limited number of genetic etiologies for BAV have been defined, family members of affected individuals display BAV along with other left-sided CHD. This has led to guidelines from the American Heart Association and American College of Cardiology that recommend echocardiographic screening of first-degree relatives of affected adults. While potentially beneficial in adults, the yield of such screening in children is unknown. The purpose of this study was to investigate a cohort of children with familial BAV to determine the frequency of development of AscAo, and to identify risk factors that contribute to abnormal aortic growth. Echocardiograms over a 10-year follow-up period were reviewed on 26 patients with familial BAV [22 male, 4 female; 22 with isolated BAV, 6 with BAV and aortic coarctation (CoA)]. All had a family history of CHD and were recruited from 2005 to 2010 as part of a genetics research study. Four aortic segments (annulus, root, sinotubular junction, ascending aorta) on parasternal long-axis echocardiographic images were measured by a single observer. The mean age at first echocardiogram was 7.1 ± 5.5 and that was 13.8 ± 6.2 years at the last echocardiogram. Only patients with > 2 echocardiograms in the 10-year period were included. Z score measurements of the aorta were plotted over time and based on these the cohort was divided into two groups: Group 1 (abnormal)-Z score for any segment > 2 or a change in Z score > 2 over follow-up; Group 2 (normal)-Z score < 2 throughout follow-up and change in Z score < 2. Nineteen out of 26 children displayed abnormal aortic growth or dilation of the aorta. BAV with right/left cusp fusion was more frequent in Group 1 (15/18) versus Group 2 (3/7) (p < 0.05). There were no significant differences in gender, aortic valve dysfunction, presence of CoA, family history, cardiac function, presence of left ventricular hypertrophy, or medication use between the 2 groups. In our longitudinal study of children with familial BAV, the majority display evidence of abnormal growth of the ascending aorta during the follow-up period consistent with AscAo and support the extension of current adult guidelines to the pediatric population. While we find that right/left cusp fusion is a risk factor for abnormal aortic growth, additional studies are needed to identify other factors to better select children who require serial screening.

Improving Situational Awareness to Decrease Emergency ICU Transfers for Hospitalized Pediatric Cardiology Patients.

Introduction: Failure to recognize and mitigate critical patient deterioration remains a source of serious preventable harm to hospitalized pediatric cardiac patients. Emergency transfers (ETs) occur 10-20 times more often than code events outside the intensive care unit (ICU) and are associated with morbidity and mortality. This quality improvement project aimed to increase days between ETs and code events on an acute care cardiology unit (ACCU) from a baseline median of 17 and 32 days to ≥70 and 90 days within 12 months. Methods: Institutional leaders, cardiology-trained physicians and nurses, and trainees convened, utilizing the Institution for Healthcare Improvement model to achieve the project aims. Interventions implemented focused on improving situational awareness (SA), including a "Must Call List," evening rounds, a visual management board, and daily huddles. Outcome measures included calendar days between ETs and code events in the ACCU. Process measures tracked the utilization of interventions, and cardiac ICU length of stay was a balancing measure. Statistical process control chart methodology was utilized to analyze the impact of interventions. Results: Within the study period, we observed a centerline shift in primary outcome measures with an increase from 17 to 56 days between ETs and 32 to 62 days between code events in the ACCU, with sustained improvement. Intervention utilization ranged from 87% to 100%, and there was no observed special cause variation in our balancing measure. Conclusions: Interventions focused on improving SA in a particularly vulnerable patient population led to sustained improvement with reduced ETs and code events outside the ICU.

Utilization of Whole Exome Sequencing to Identify Causative Mutations in Familial Congenital Heart Disease.

BACKGROUND: Congenital heart disease (CHD) is the most common type of birth defect with family- and population-based studies supporting a strong genetic cause for CHD. The goal of this study was to determine whether a whole exome sequencing (WES) approach could identify pathogenic-segregating variants in multiplex CHD families. METHODS AND RESULTS: WES was performed on 9 kindreds with familial CHD, 4 with atrial septal defects, 2 with patent ductus arteriosus, 2 with tetralogy of Fallot, and 1 with pulmonary valve dysplasia. Rare variants (<1% minor allele frequency) that segregated with disease were identified by WES, and variants in 69 CHD candidate genes were further analyzed. These selected variants were subjected to in silico analysis to predict pathogenicity and resulted in the discovery of likely pathogenic mutations in 3 of 9 (33%) families. A GATA4 mutation in the transactivation domain, p.G115W, was identified in familial atrial septal defects and demonstrated decreased transactivation ability in vitro. A p.I263V mutation in TLL1 was identified in an atrial septal defects kindred and is predicted to affect the enzymatic functionality of TLL1. A disease-segregating splice donor site mutation in MYH11 (c.4599+1delG) was identified in familial patent ductus arteriosus and found to disrupt normal splicing of MYH11 mRNA in the affected individual. CONCLUSIONS: Our findings demonstrate the clinical utility of WES to identify causative mutations in familial CHD and demonstrate the successful use of a CHD candidate gene list to allow for a more streamlined approach enabling rapid prioritization and identification of likely pathogenic variants from large WES data sets. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov; Unique Identifier: NCT0112048.

Is Aortic Valve Leaflet Morphology Predictive of Outcome in Pediatric Aortic Valve Stenosis?

BACKGROUND: Initial palliative treatment of congenital aortic valve stenosis consists of either surgical commissurotomy or transcatheter balloon valvuloplasty. The basis for selection of primary approach usually is ill defined. It was hypothesized that aortic valve characteristics may be helpful in directing choice of intervention. This study assesses the impact of valve morphology on time to reintervention after catheter- or surgical-based therapy. METHODS: A retrospective review of preprocedural echocardiographic aortic outflow characteristics was compared with outcomes of primary surgical or balloon valve interventions. Characteristics studied included (1) annular dimension; (2) leaflet number; (3) leaflet excursion; and (4) degree of leaflet coaptation. Patients included those <20 years with a primary diagnosis of aortic stenosis (AS) and no other hemodynamically significant lesions at our institutions from 2000 to 2011. A total of 102 patients were included, 31 classified as having critical and 71 as having noncritical aortic stenosis. Of the patients, 79 were male, and 50 underwent primary catheter intervention. Echo parameters were compared with procedural outcome as defined by death or need for reintervention. Receiver operator curves were utilized to determine the point within each morphologic feature where the greatest difference occurred. This was utilized as the distinguishing point within each the morphologic group. Analysis was conducted separately for critical and noncritical aortic stenosis. RESULTS: Kaplan-Meier analysis demonstrated no significant difference in time to reintervention or death whether initial palliation consisted of surgical commissurotomy or balloon valvuloplasty with respect to any of the morphologic characteristics studied. CONCLUSION: Patients with AS do equally well with surgical commissurotomy or balloon valvuloplasty as initial palliation. This holds true for those with either critical or noncritical aortic stenosis. Valve morphology did not help in selection of initial palliative strategy. Current technologies should enable an improved selection of initial palliative approach through thoughtful, randomized trials.

Should repair of partial atrioventricular septal defect be delayed until later in childhood?

Surgical repair of partial atrioventricular septal defects (AVSD) has been successful for more than 60 years. However, recent data from the Pediatric Heart Network show that 31% of patients have moderate or severe left atrioventricular valve regurgitation (LAVVR) at follow-up. Previously, our institution found that only 9% of patients had more than moderate LAVVR at the last follow-up. Our objective was to determine the long-term outcomes after repair of partial AVSD in the current era. We reviewed all patients with partial AVSD who had primary biventricular repair from January 1995 to June 2011 at our institution. The Kaplan-Meier method was used to estimate the survival free of an event, and factors were evaluated for an association with each outcome using the log-rank test. All 105 patients with partial AVSD who had surgery during this period were evaluated. The median age at surgery was 7.9 years. The overall survival rate at 1 year was 97%. Median follow-up was 5.3 years (interquartile range 1.7 to 11.1). At 3 years, the survival rate free from reoperation was 89%. Thirteen patients required reoperations with the most common reason being LAVVR. A total of 10 patients developed more than moderate LAVVR with a cumulative incidence of 8% by 2 years. The discrepancy with the Pediatric Heart Network data may be due to the later age of operation for patients in our cohort suggesting that elective repair of partial AVSD should be deferred until children are somewhat older (ages 5 to 8 years). Neither patient age (p = 0.11) nor severity of preoperative LAVVR (p = 0.16) were identified as statistically significant risk factors. In conclusion, there is less morbidity and mortality after surgical repair for partial AVSD.