Type A aortic dissection in patients with bicuspid aortic valves: clinical and pathological comparison with tricuspid aortic valves.

Objective: Bicuspid aortic valve (BAV) is associated with a higher risk of type A aortic dissection (AD) compared with tricuspid aortic valve (TAV). We sought to study differences between patients with BAV and TAV with AD.

Design And Setting: Observational descriptive analysis of clinical, imaging and pathological characteristics of all patients with confirmed BAV and AD from 1980-2010, compared with a consecutive TAV group with AD.

Results: Of 47 patients with BAV (mean age 58 ± 14, 77% male), 31 (66%) had acute AD, 16 (34%) had chronic AD, 40 (85%) had typical BAV, 32 (68%) had hypertension and 11 (23%) had previous aortic coarctation repair. Of 53 patients with TAV (mean age 66 ± 13 (p=0.007), 76% male), 34 (66%) had acute AD (p=1.0) and 46 (87%) had hypertension (p=0.03). More patients with BAV had known aortic dilatation prior to AD (49% versus 17%, p=0.001). Presentation symptoms were identical between groups (p=NS). Maximal ascending aortic diameter at AD was higher in patients with BAV (66 ± 15 mm vs 56 ± 11 mm, p=0.0004). Previous aortic valve replacement (AVR) was more common in BAV (23% vs 6%, p=0.02). Of 11 patients with BAV with previous isolated AVR, 7 had ≥ moderate ascending aorta dilatation at the time of surgery. Patients with BAV had increased aortic jet velocity (28% vs 10%) and more severe aortic stenosis (19% vs 0%) at presentation (p=0.04 and 0.002, respectively). In acute AD, aortic medial degeneration affected 75% of BAV specimens and 41% TAV specimens (p=0.01) while aortic atherosclerosis was more frequent in TAV (56% vs 26%, p=0.02).

Conclusions: Compared with patients with TAV, patients with BAV with type A AD are younger, have less hypertension, more valve stenosis and previous AVR, higher maximal aortic dimension, worse aortic medial degeneration, high prevalence of aortic coarctation, and 1 out of 2 have known aortic dilatation prior to AD. Implementation of current guidelines could have theoretically prevented AD in several patients with BAV.