The actual incidence of ascending aorta complications (AACs) in adults with bicuspid aortic valve (BAV) and the role of associated coarctation of the aorta (COA) as an independent risk factor for AACs remain unknown. From the Adult Congenital Heart Disease database at La Paz Hospital, 631 patients in whom a BAV was diagnosed by echocardiography or surgical inspection since December 1989 were identified. These patients were then further subdivided into 2 groups according to the presence of an associated COA. AACs included aortic aneurysms (ascending aorta > or =55 mm) and aortic dissection, rupture, or perforation. Patients with a BAV and COA had a greater prevalence of AACs (8.0%) than those with an isolated BAV (3.7%; p = 0.037). The coexistence of COA was the only significant predictor of AACs (odds ratio 4.7, 95% confidence interval 1.5 to 15; p = 0.01). From the total patient group with a BAV, the clinical and echocardiographic data were reviewed for 341 patients without an AAC at baseline (97 with and 244 without COA) who had undergone serial examinations >1 year apart. The median follow-up was 7 years (interquartile range 3.5 to 10.2; total 2,436 patient-years). A new AAC occurred in 13 patients (0.5/100 patient-years). The incidence of AACs was 1.3/100 patient-years in the COA group versus 0.2/100 patient-years in the non-COA group (hazard ratio 7.5, 95% confidence interval 2.0 to 28, p = 0.002). All acute aortic events (dissection or rupture) at follow-up occurred in patients with a BAV and COA. In conclusion, the long-term incidence of AACs in patients with isolated BAV is low, but patients with BAV and associated COA are at increased risk.