Contributions of Germline and Somatic Mosaic Genetics to Thoracic Aortic Aneurysms in Nonsyndromic Individuals.

BACKGROUND: Thoracic aortic aneurysm (TAA) is associated with significant morbidity and mortality. Although individuals with family histories of TAA often undergo clinical molecular genetic testing, adults with nonsyndromic TAA are not typically evaluated for genetic causes. We sought to understand the genetic contribution of both germline and somatic mosaic variants in a cohort of adult individuals with nonsyndromic TAA at a single center. METHODS AND RESULTS: One hundred eighty-one consecutive patients <60 years who presented with nonsyndromic TAA at the Massachusetts General Hospital underwent deep (>500×) targeted sequencing across 114 candidate genes associated with TAA and its related functional pathways. Samples from 354 age- and sex-matched individuals without TAA were also sequenced, with a 2:1 matching. We found significant enrichments for germline (odds ratio [OR], 2.44, P=4.6×10-6 [95% CI, 1.67-3.58]) and also somatic mosaic variants (OR, 4.71, P=0.026 [95% CI, 1.20-18.43]) between individuals with and without TAA. Likely genetic causes were present in 24% with nonsyndromic TAA, of which 21% arose from germline variants and 3% from somatic mosaic alleles. The 3 most frequently mutated genes in our cohort were FLNA (encoding Filamin A), NOTCH3 (encoding Notch receptor 3), and FBN1 (encoding Fibrillin-1). There was increased frequency of both missense and loss of function variants in TAA individuals. CONCLUSIONS: Likely contributory dominant acting genetic variants were found in almost one quarter of nonsyndromic adults with TAA. Our findings suggest a more extensive genetic architecture to TAA than expected and that genetic testing may improve the care and clinical management of adults with nonsyndromic TAA.

Prognostic Value of Exercise Stress Echocardiography in Pediatric Cardiac Transplant Recipients.

BACKGROUND: Cardiac allograft vasculopathy (CAV) is a leading cause of long-term morbidity and mortality in pediatric heart transplant (HTx) recipients. Exercise stress echocardiography (ESE) has been shown to be useful in the detection of angiographically confirmed coronary artery disease in children. However, the prognostic utility of ESE for prediction of cardiac events in HTx survivors is unknown. OBJECTIVES: We aim to assess whether an abnormal (positive) ESE is be associated with a higher risk of future cardiovascular (CV) outcomes in pediatric HTx recipients. METHODS: We conducted a retrospective review of CV outcomes in a cohort of 95 pediatric HTx recipients who underwent 188 ESEs over a 10-year period. A composite endpoint for CV events including myocardial infarction, hospitalization for nonrejection heart failure, coronary revascularization, need for repeat transplantation, and death was used. Based on the interpretation of the ESE results, each ESE study was classified for this study as either positive (abnormal) or negative (normal) for ischemia. Results of the coronary angiograms performed near the time of ESE were also assessed and classified for this study as positive (abnormal) or negative (normal) for CAV according to standard HTx criteria for CAV. RESULTS: Fifty-one (27%) ESEs were positive for ischemia. There was a total of 35 CV events in 23 patients. A positive ESE was associated with increased risk of any CV event (hazard ratio = 3.55; 95% CI, 1.52, 8.28), as well as an increased risk of CV death (hazard ratio = 3.19; 95% CI, 1.23, 8.28). Freedom from composite CV outcome at 1, 2, and 3 years following a positive ESE was 89.9% (95% CI = 77.3%, 95.7%), 81.5% (95% CI = 65.9%, 90.5%), and 63.2% (95% CI = 41.9%, 78.5%), respectively. Freedom from composite CV outcome at 1, 2, and 3 years following a negative ESE was 99.3% (94.8, 99.9), 98.4% (93.6, 99.6), and 97.0% (90.6, 99.1), respectively. No patient died within 1 year of a negative ESE. CONCLUSIONS: In this largest study of ESE in pediatric HTx recipients, a positive or abnormal ESE is associated with increased future CV morbidity and mortality. Conversely, a negative ESE can help predict CV event-free survival. Even in the setting of a normal coronary angiogram, our pilot data show that an abnormal ESE may still be clinically important. Use of ESE in follow-up may improve risk stratification and management of pediatric HTx recipients.

Déjà Vu: Recurrent Sudden Cardiac Arrests in a Child With an Anomalous Left Coronary Artery.

Sudden cardiac arrest from anomalous coronary artery from the opposite sinus of Valsalva is rarely observed in children under 10 years of age. We report a 7-week-old infant with a brief resolved unexplained event from left anomalous aortic origin of a coronary artery who underwent unroofing and again developed syncope at 8 years of age. Ischemia was detected by stress echocardiography both times. (Level of Difficulty: Advanced.).