Abstract
CASE SUMMARY: Quadricuspid aortic valve is a rare congenital malformation with prevalence of <0.05%, often manifesting in mid- to late adulthood with aortic regurgitation (AR). We present a case of a 60-year-old man with chronic severe AR due to phenotype F quadricuspid aortic valve and mild to moderate functional mitral regurgitation. Cardiac catheterization revealed multivessel coronary artery disease. The patient underwent successful surgical aortic valve replacement with a bioprosthesis and 2-vessel coronary artery bypass graft surgery. Echocardiography at 1-month follow-up showed improved left ventricular volumes, normal aortic bioprosthesis, and trivial mitral regurgitation. This case highlights the role of echocardiography in diagnosing quadricuspid aortic valve and guiding management. TAKE-HOME MESSAGES: Quadricuspid aortic valve is a rare cause of AR that can be readily diagnosed on echocardiography. Surgical aortic valve replacement is an effective treatment for severe symptomatic AR due to quadricuspid aortic valve.