Prevalence of Bicuspid Aortic Valve and Associated Aortopathy in Newborns in Copenhagen, Denmark

Importance The prevalence and characteristics of bicuspid aortic valve (BAV) are mainly reported from selected cohorts. BAV is associated with aortopathy, but it is unclear if it represents a fetal developmental defect or is secondary to abnormal valve dynamics. Objective To determine the prevalence of BAV and BAV subtypes and to describe the associated aortopathy in a large, population-based cohort of newborns. Design, Setting, and Participants The Copenhagen Baby Heart Study was a cross-sectional, population-based study open to all newborns born in Copenhagen between April 1, 2016, and October 31, 2018. Newborns with BAV were matched 1:2 to newborns with a tricuspid aortic valve (non-BAV group) on sex, singleton/twin pregnancy, gestational age, weight, and age at time of examination. Exposures Transthoracic echocardiography within 60 days after birth. Main Outcomes and Measures Primary outcome was BAV prevalence and types, ie, number of raphes and spatial orientation of raphes or cusps (no raphes), according to the classification system of Sievers and Schmidtke (classified as type 0, 1, or 2, with numbers indicating the number of raphes). Secondary outcome was valve function and BAV-associated aortopathy, defined as aortic diameter z score of 3 or greater or coarctation. Results In total, 25 556 newborns (51.7% male; mean age, 12 [SD, 8] days) underwent echocardiography. BAV was diagnosed in 196 newborns (prevalence, 0.77% [95% CI, 0.67%-0.88%]), with male-female ratio 2.1:1. BAV was classified as type 0 in 17 newborns (8.7% [95% CI, 5.5%-13.5%]), type 1 in 178 (90.8% [95% CI, 86.0%-94.1%]) (147 [75.0% {95% CI, 68.5%-80.5%}] right-left coronary raphe, 27 [13.8% {95% CI, 9.6%-19.3%}] right coronary-noncoronary raphe, 4 [2.0% {95% CI, 0.8%-5.1%}] left coronary-noncoronary raphe), and type 2 in 1 (0.5% [95% CI, 0.1%-2.8%]). Aortic regurgitation was more prevalent in newborns with BAV (n = 29 [14.7%]) than in those without BAV (1.3%) (absolute % difference, 13.4% [95% CI, 7.8%-18.9%]; P < .001). Newborns with BAV had higher flow velocities across the valve (0.67 [95% CI, 0.65-0.69] m/s vs 0.61 [95% CI, 0.60-0.62] m/s; mean difference, 0.06 m/s [95% CI, 0-0.1]) and larger aortic root and tubular ascending aortic diameters than those without BAV (10.7 [95% CI, 10.7-10.9] mm vs 10.3 [95% CI, 10.2-10.4] mm; mean difference, 0.43 mm [95% CI, 0.2-0.6 mm] and 9.8 [95% CI, 9.6-10.0] mm vs 9.4 [95% CI, 9.3-9.5] mm; mean difference, 0.46 mm [95% CI, 0.30-0.70], respectively) (P < .001 for all). Aortopathy was seen in 65 newborns (33.2%) with BAV (62 with aortic z score >= 3; 3 with coarctation). Conclusions and Relevance Among newborns in Copenhagen, the prevalence of BAV was 0.77%. Aortopathy was common in newborns with BAV, suggesting that it also represents a fetal malformation. Question What is the prevalence of bicuspid aortic valve among newborns and what is the extent of associated disease of the aorta? Findings This cross-sectional study included 25 556 newborns in Denmark between 2016 and 2018 who underwent transthoracic echocardiography. The prevalence of bicuspid aortic valve was 0.77%; of these, aortopathy was present in 33%. Meaning Among newborns in Copenhagen, the prevalence of bicuspid aortic valve was 0.77% and associated aortic disease was common, suggesting that it was a fetal malformation. This population epidemiology study describes the prevalence of bicuspid aortic valve (BAV) and BAV subtypes, and of accompanying enlarged aortic diameter or coarctation, in Danish newborns born in Copenhagen 2016-2018.