Genetic Testing Guidelines Impact Care in Newborns with Congenital Heart Defects

Objective: To evaluate genetic evaluation practices in newborns with the most common birth defect, congenital heart defects (CHD), we determined the prevalence and the yield of genetic evaluation across time and across patient subtypes, before and after implementation of institutional genetic testing guidelines. Study design: This was a retrospective, cross-sectional study of 664 hospitalized newborns with CHD using multivariate analyses of genetic evaluation practices across time and patient subtypes. Results: Genetic testing guidelines for hospitalized newborns with CHD were implemented in 2014, and subsequently genetic testing increased (40% in 2013 and 75% in 2018, OR 5.02, 95% CI 2.84-8.88, P < .001) as did medical geneticists' involvement (24% in 2013 and 64% in 2018, P < .001). In 2018, there was an increased use of chromosomal microarray (P < .001), gene panels (P = .016), and exome sequencing (P = .001). The testing yield was high (42%) and consistent across years and patient subtypes analyzed. Increased testing prevalence (P < .001) concomitant with consistent testing yield (P = .139) added an estimated 10 additional genetic diagnoses per year, reflecting a 29% increase. Conclusions: In patients with CHD, yield of genetic testing was high. After implementing guidelines, genetic testing increased significantly and shifted to newer sequence-based methods. Increased use of genetic testing identified more patients with clinically important results with potential to impact patient care

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Poster presentatio

Learning to Crawl: Determining the Role of Genetic Abnormalities on Postoperative Outcomes in Congenital Heart Disease

Background Our cardiac center established a systematic approach for inpatient cardiovascular genetics evaluations of infants with congenital heart disease, including routine chromosomal microarray (CMA) testing. This provides a new opportunity to investigate correlation between genetic abnormalities and postoperative course. Methods and Results Infants who underwent congenital heart disease surgery as neonates (aged ≤28 days) from 2015 to 2020 were identified. Cases with trisomy 21 or 18 were excluded. Diagnostic genetic results or CMA with variant of uncertain significance were considered abnormal. We compared postoperative outcomes following initial congenital heart disease surgery in patients found to have genetic abnormality to those who had negative CMA. Among 355 eligible patients, genetics consultations or CMA were completed in 88%. A genetic abnormality was identified in 73 patients (21%), whereas 221 had negative CMA results. Genetic abnormality was associated with prematurity, extracardiac anomaly, and lower weight at surgery. Operative mortality rate was 9.6% in patients with a genetic abnormality versus 4.1% in patients without an identified genetic abnormality (P=0.080). Mortality was similar when genetic evaluations were diagnostic (9.3%) or identified a variant of uncertain significance on CMA (10.0%). Among 14 patients with 22q11.2 deletion, the 2 mortality cases had additional CMA findings. In patients without extracardiac anomaly, genetic abnormality was independently associated with increased mortality (P=0.019). CMA abnormality was not associated with postoperative length of hospitalization, extracorporeal membrane oxygenation, or >7 days to initial extubation. Conclusions Routine genetic evaluations and CMA may help to stratify mortality risk in severe congenital heart disease with syndromic or nonsyndromic presentations

Rapid Genome Sequencing Shows Diagnostic Utility In Infants With Congenital Heart Defects

Congenital heart disease (CHD) is the most common birth defect and a leading cause of infant mortality. CHD often has a genetic etiology and recent studies demonstrate utility in genetic testing. In clinical practice, decisions around genetic testing choices continue to evolve, and the incorporation of rapid genome sequencing (rGS) in CHD has not been well studied. Though smaller studies demonstrate the value of rGS, they also highlight the burden of results interpretation. We analyze genetic testing in CHD at two time-points, in 2018 and 2022-2023, across a change in clinical testing guidelines from chromosome microarray (CMA) to rGS. Analysis of 421 hospitalized infants with CHD demonstrated consistent genetic testing across time. Overall, after incorporation of rGS in 2022-2023, the diagnostic yield was 6.8% higher compared to 2018, and this pattern was consistent across all patient subtypes analyzed. In 2018, CMA was the most common test performed, with diagnostic results for CHD in 14.3%, while in 2022-2023, rGS was the most frequent test performed, with results diagnostic for CHD in 16.9%. Additionally, rGS identified 44% more unique genetic diagnoses than CMA. This is the largest study to highlight the value of rGS in CHD and has important implications for management