Natural history of asymptomatic patients with normally functioning or minimally dysfunctional bicuspid aortic valve in the community

BACKGROUND - Bicuspid aortic valve is frequent and is reported to cause numerous complications, but the clinical outcome of patients diagnosed with normal or mildly dysfunctional valve is undefined. METHODS AND RESULTS - In 212 asymptomatic community residents from Olmsted County, Minn (age, 32±20 years; 65% male), bicuspid aortic valve was diagnosed between 1980 and 1999 with ejection fraction ≥50% and aortic regurgitation or stenosis, absent or mild. Aortic valve degeneration at diagnosis was scored echocardiographically for calcification, thickening, and mobility reduction (0 to 3 each), with scores ranging from 0 to 9. At diagnosis, ejection fraction was 63±5% and left ventricular diameter was 48±9 mm. Survival 20 years after diagnosis was 90±3%, identical to the general population (P=0.72). Twenty years after diagnosis, heart failure, new cardiac symptoms, and cardiovascular medical events occurred in 7±2%, 26±4%, and 33±5%, respectively. Twenty years after diagnosis, aortic valve surgery, ascending aortic surgery, or any cardiovascular surgery was required in 24±4%, 5±2%, and 27±4% at a younger age than the general population (P<0.0001). No aortic dissection occurred. Thus, cardiovascular medical or surgical events occurred in 42±5% 20 years after diagnosis. Independent predictors of cardiovascular events were age ≥50 years (risk ratio, 3.0; 95% confidence interval, 1.5 to 5.7; P<0.01) and valve degeneration at diagnosis (risk ratio, 2.4; 95% confidence interval, 1.2 to 4.5; P=0.016; >70% events at 20 years). Baseline ascending aorta ≥40 mm independently predicted surgery for aorta dilatation (risk ratio, 10.8; 95% confidence interval, 1.8 to 77.3; P<0.01). CONCLUSIONS - In the community, asymptomatic patients with bicuspid aortic valve and no or minimal hemodynamic abnormality enjoy excellent long-term survival but incur frequent cardiovascular events, particularly with progressive valve dysfunction. Echocardiographic valve degeneration at diagnosis separates higher-risk patients who require regular assessment from lower-risk patients who require only episodic follow-up.