New insights into bicuspid aortic valve disease: the elongated anterior mitral leaflet.

OBJECTIVES The bicuspid aortic valve (BAV) is associated with various cardiovascular malformations, most predominantly with dilatation of the aortic root and ascending aorta. After sporadic observations of various BAV-associated mitral valve pathologies, we sought to systematically examine the mitral valve morphology in patients with a BAV. METHODS Forty-four operated patients with a BAV (type I L/R) and 40 operated patients with a tricuspid aortic valve (TAV) as well as 20 healthy subjects (Normal) were examined by means of transthoracic echocardiography. In all patients, the primary operative indication was aortic valve pathology (stenosis/regurgitation), and no patients with degenerative mitral valve pathology were included. RESULTS In patients with a BAV, the anterior mitral leaflet (AML) was significantly elongated in comparison with patients with a TAV and Normal subjects (33.2 ± 6.6 vs 27.7 ± 3.2 vs 27.0 ± 1.9 mm; P < 0.001). Regression analysis revealed that patients with a BAV had significantly elongated AML (P < 0.001) even after correcting for the mitral annulus (MA) diameter and somatometric characteristics (weight, height, body surface area, age). Furthermore, patients with a BAV and concomitant aortic valve insufficiency had significantly elongated AML in comparison with the other groups (35.2 ± 7.6 vs 28.4 ± 3.7 mm; P < 0.001). This difference persisted even after correcting for MA diameter and somatometric differences (P < 0.001). AML heights >32 mm in patients undergoing aortic root/valve procedures were highly predictive of the presence of a BAV [specificity: 90%, positive predictive value: 82%, area under curve: 0.80 (95% CI: 0.71-0.88)]. CONCLUSIONS We provide evidence that the cardiovascular alterations observed in the BAV are not limited to the aortic valve or ascending aorta but also involve the AML, and seem to be more pronounced in patients with a BAV with concomitant, clinically significant aortic regurgitation.