Beyond Cusp Count: Bicuspid Function in a Quadricuspid Aortic Valve

Quadricuspid aortic valve is a rare congenital anomaly usually associated with regurgitation. A young woman underwent surveillance after cardiovascular magnetic resonance imaging demonstrated four equal cusps in diastole but bicuspid-type systolic opening from fusion of the left and non-coronary cusps. By 2025, eccentric regurgitation was severe on echocardiography and moderate-to-severe on magnetic resonance imaging, with a regurgitant fraction of 31% and mild left ventricular dilatation. Increasing breathlessness and declining peak oxygen uptake prompted multidisciplinary review. Valve replacement with ascending aortic support was recommended, and she was considered suitable for a Ross procedure with personalised external aortic root support.