Coexistent bicuspid aortic valve and mitral valve prolapse: epidemiology, phenotypic spectrum, and clinical implications

Bicuspid aortic valve (BAV) and mitral valve prolapse (MVP) are common but the prevalence and significance of coexistent conditions are unknown. This study investigated the prevalence, phenotypic expression, and clinical significance of coexistent MVP-BAV.

Retrospective comparison of MVP-BAV and MVP-tricuspid aortic valve (TAV) prevalence including de novo echocardiographic analysis of all MVP-BAV patients between 2005 and 2015 was performed. The community prevalence of MVP-BAV was 2.7% vs. 3.4% for MVP-TAV (P = 0.45). Posterior mitral leaflet (PML)-MVP was the most common phenotype in both BAV and TAV (P = 0.38), but anterior mitral leaflet (AML)-MVP was twice more prevalent in BAV (31% vs. 15%, P < 0.0001). Among 130 subjects with coexistent MVP-BAV (81% men, 51 ± 16 years old), 31 (24%) exhibited AML:PML length ratio ≥3:1, termed large-AML prolapse (LAP-BAV), who had predominant BAV regurgitation when compared with those with non-LAP-BAV (P ≤ 0.001). An extreme phenotype of LAP-BAV with giant-AML prolapse and diminutive PML (GAP-BAV) was identified in 18/130 (14%) subjects. Compared with posterior-MVP-BAV, GAP-BAV patients were younger (42 ± 15 vs. 64 ± 12 years, P < 0.0001), had larger aortic annulus (28 ± 3 vs. 26 ± 2 mm, P = 0.01), and 61% had ≥ moderate BAV regurgitation (vs. 16%, P = 0.0007). Mitral repair occurred in 37/130 (28%) subjects. After median follow-up 5.5 months (4–83), 4/5 (80%) GAP-BAV patients required redo surgery for recurrent mitral regurgitation vs. 2/31 (6%) for non-LAP-BAV (P = 0.001).

The community prevalence of coexistent MVP-BAV is comparable to MVP-TAV and their most common phenotype is posterior-MVP. However, anterior-MVP is twice as prevalent in MVP-BAV. A large-AML phenotype (LAP-BAV) with predominant BAV regurgitation affects 24% of MVP-BAV patients. An extreme phenotype of anterior-MVP (GAP-BAV) affects 14% of BAV patients; characterized by exceptionally large AML, diminutive PML, high mitral and aortic regurgitation prevalence, and high mitral repair failure rate.