Uncommon presentations of type A quadricuspid aortic valve in the Septuagenarian

Background: Quadricuspid aortic valve (QAV) is a rare congenital anomaly characterized by the presence of four cusps instead of the usual three. It is estimated to occur in less than 0.05% of the population, with Type A (four equal-sized leaflets) accounting for roughly 30% of QAV subtypes. Based on limited clinical series, the usual presentation is progressive aortic valve regurgitation (AR) with symptoms occurring in the fourth to sixth decade of life. Severe aortic valve stenosis (AS) and acute AR are very uncommon. Case presentation: We describe two cases of Type A QAV in patients who remained asymptomatic until their seventies with very uncommon presentations: one with severe AS and one with acute, severe AR and flail leaflet. In Case A, a 72-year-old patient with history of moderate AS presents to clinic with progressive exertional dyspnea. During work-up for transcatheter vs. surgical replacement pre-operative computed tomography angiogram (CTA) reveals a quadricuspid aortic valve with severe AS, and the patient undergoes surgical aortic valve replacement. Pre-discharge transthoracic echocardiography (TTE) shows good prosthetic valve function with no gradient or regurgitation. In Case B, a 76-year-old patient is intubated upon arrival to the hospital for acute desaturation, found to have wide open AR on catheterization, and transferred for emergent intervention. Intraoperative TEE reveals QAV with flail leaflet and severe AR. Repair is considered but deferred ultimately due to emergent nature. Post-operative TTE demonstrates good prosthetic valve function with no regurgitation and normal biventricular function. Conclusions: QAV can present as progressive severe AS and acute AR, with symptoms first occurring in the seventh decade of life. The optimal treatment for QAV remains uncertain. Although aortic valve repair or transcatheter option may be feasible in some patients, aortic valve replacement remains a tenable option.