Incidence of Aortic Complications in Patients With Bicuspid Aortic Valves
What is the incidence of aortic complications in patients with bicuspid aortic valve (BAV), in a community cohort and in the general population?
The investigators conducted a comprehensive assessment of aortic complications of patients with BAV living in a population-based setting in Olmsted County, MN. They analyzed long-term follow-up of a cohort of all Olmsted County residents diagnosed with definite BAV by echocardiography from 1980 to 1999, and searched for aortic complications of patients whose bicuspid valves had gone undiagnosed. The last year of follow-up was 2008-2009. The main outcome measures were thoracic aortic dissection, ascending aortic aneurysm, and aortic surgery.
The cohort included 416 consecutive patients with definite BAV diagnosed by echocardiography, mean (standard deviation) follow-up of 16 (7) years (6,530 patient-years). Aortic dissection occurred in 2 of 416 patients; incidence of 3.1 (95% confidence interval [CI], 0.5-9.5) cases per 10,000 patient-years, age-adjusted relative-risk 8.4 (95% CI, 2.1-33.5; p = 0.003) compared with the county’s general population. Aortic dissection incidences for patients 50 years or older at baseline and bearers of aortic aneurysms at baseline were 17.4 (95% CI, 2.9-53.6) and 44.9 (95% CI, 7.5-138.5) cases per 10,000 patient-years, respectively. Comprehensive search for aortic dissections in undiagnosed bicuspid valves revealed two additional patients, allowing estimation of aortic dissection incidence in bicuspid valve patients irrespective of diagnosis status (1.5; 95% CI, 0.4-3.8 cases per 10,000 patient-years), which was similar to the diagnosed cohort. Of 384 patients without baseline aneurysms, 49 developed aneurysms at follow-up, incidence of 84.9 (95% CI, 63.3-110.9) cases per 10,000 patient-years and an age-adjusted relative risk 86.2 (95% CI, 65.1-114; p < 0.001 compared with the general population). The 25-year rate of aortic surgery was 25% (95% CI, 17.2%-32.8%).
The authors concluded that in the population of patients with BAV, the incidence of aortic dissection over a mean of 16 years of follow-up was low, but significantly higher than in the general population.
This study suggests that patients with BAV develop a clinical aortopathy that affects clinical outcome. The risk of aortic dissection in this cohort with BAV was approximately 8 times higher than in the general population, but despite this high relative risk, the absolute incidence of aortic dissection remains very low. The dissection incidence was higher in patients older than 50 years and higher in those with baseline aortic aneurysms, highlighting the importance of close monitoring and implementation of current guidelines in these subgroups. Future research should focus on elucidating biological pathways of BAV aortopathy amenable to medical treatment, as well as identifying novel markers for refining risk prediction of aortic dissection in these patients.
Keywords: Outcome Assessment (Health Care), Incidence, Risk, Follow-Up Studies, Heart Valve Diseases, Confidence Intervals, Transduction, Genetic, Mitral Valve, Echocardiography
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