Comparison of ascending aortic cohesion between patients with bicuspid aortic valve stenosis and regurgitation

OBJECTIVES: A bicuspid aortic valve (BAV) is commonly associated with aortic wall abnormalities, including dilatation of the ascending aorta and increased potential for aortic dissection. We compared the mechanical properties of the aortic wall of BAV patients with aortic valve stenosis (AS) and regurgitation (AR) using a dissectometer, a device mimicking transverse aortic wall shear stress. METHODS: Between March 2010 and February 2013, 85 consecutive patients with bicuspid aortic valve undergoing open aortic valve replacement at our institution were prospectively enrolled, presenting either with stenosis (Group 1, n = 58) or regurgitation (Group 2, n = 27). Aortic wall cohesion measured by the dissectometer (Parameters P7, P8 and P9), aortic diameters measured by transoesophageal echocardiography (TOE) and thickness of the wall were compared. One patient presenting with the Marfan syndrome was excluded from the study. RESULTS: Patients with aortic regurgitation were significantly younger (48.2 ± 15.8 vs 64.7 ± 10.7, P < 0.001), and had a significantly thicker aortic wall (2.30 ± 0.49 mm vs 2.06 ± 0.35 mm, P = 0.029). Transoesophageal echocardiography diameters (annulus, aortic sinuses and sinotubular junction) were significantly larger in the AR group (27.3 ± 3.6 vs 25.5 ± 2.4, P = 0.008; 41.1 ± 7.7 vs 36.7 ± 8.0, P = 0.011; 37.6 ± 9.7 vs 33.8 ± 9.1, P = 0.049). The ascending aortic diameter did not differ (43.2 ± 10.6 vs 40.3 ± 9.1, P = 0.292). Patients with AR had significantly worse aortic cohesion, as measured by shear stress testing (P7: 97.2 ± 45.0 vs 145.5 ± 84.9, P = 0.015; P8: 2.00 ± 0.65 vs 3.82 ± 1.56, P < 0.001; P9: 2.96 ± 0.82 vs 4.98 ± 1.80, P < 0.001) compared with those with AS. CONCLUSIONS: We observed significantly worse aortic wall cohesion, a thicker aortic wall and a larger aortic root in patients presenting with bicuspid AR compared with patients with AS. These results suggest that bicuspid AR represents a different disease process with possible involvement of the ascending aorta, as demonstrated by dissectometer examination.