Posterior Mitral Valve Hypoplasia: Three Clinical Cases and a Review of the Literature

Background: Posterior mitral leaflet hypoplasia is a rare condition, generally diagnosed in children. This paper presents three adult cases of posterior leaflet hypoplasia and comprehensively reviews the existing literature. Methods and Results: All patients presented with severe mitral regurgitation necessitating hospitalization. Transthoracic and transesophageal echocardiography were performed to determine the underlying etiology, revealing pronounced posterior mitral leaflet hypoplasia. Each case was evaluated by a multidisciplinary heart team. Surgical mitral valve intervention was feasible in two patients. In one high-risk patient, percutaneous treatment options for MR were explored but ultimately deemed unsuitable due to the anatomical characteristics of the valve. The patient was consequently managed conservatively with medical therapy. Conclusions: These cases demonstrate that posterior mitral leaflet hypoplasia may constitute an underrecognized cause of severe primary mitral regurgitation in adults. The management of such cases can be particularly challenging due to the atypical valvular morphology.