Aortic Valve Plasty for Coexistence of Discrete Subvalvular Aortic Stenosis and Quadricuspid Aortic Valve: A Case Report

Subvalvular aortic stenosis typically manifests at a young age and rarely presents in adulthood. It may cause left ventricular outflow tract stenosis, which requires surgical treatment in severe cases. The coexistence of discrete subvalvular aortic stenosis and quadricuspid aortic valve is a highly unusual finding. We present a case of a patient with coexisting discrete subvalvular aortic stenosis and quadricuspid aortic valve, who underwent aortic valve plasty and subvalvular aortic stenotomy. A 63-year-old woman with a history of shortness of breath on exertion was referred to our hospital after being diagnosed with discrete subvalvular aortic stenosis and quadricuspid aortic valve at another hospital. Echocardiography revealed membranous tissue below the aortic valve and a quadricuspid aortic valve. Dobutamine stress echocardiography showed a mean pressure gradient of 75 mmHg and Vmax of 5.9 m/s in the subaortic membranous area. The subaortic valve membranous structures were first resected during surgery to release the subaortic stenosis. The aortic valve had four cusps with an accessory cusp between the right and left coronary cusps. Next, the right coronary cusp was sutured to the accessory cusp and converted to a single valve. Intraoperative transesophageal echocardiography showed trivial aortic regurgitation. The intraoperatively resected subvalvular tissue contained fibrous connective tissue with fibrous thickening and mucinous degeneration. At one-year postoperative follow-up, there is no subvalvular aortic stenosis and aortic regurgitation recurrence, and the patient is doing well. Long-term outcomes of aortic valvuloplasty for quadricuspid aortic valves are not well-characterized in the literature. Owing to the high relapse rate of subvalvular aortic stenosis, rigorous follow-up with echocardiography every six to twelve months is essential to evaluate the long-term success of aortic valve plasty.