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

## TL;DR

This paper reports three rare adult cases of posterior mitral valve hypoplasia and highlights the challenges in diagnosing and treating this condition.

## Contribution

The study presents previously underreported adult cases of posterior mitral leaflet hypoplasia and discusses management challenges.

## Key findings

- Three adult patients presented with severe mitral regurgitation due to posterior leaflet hypoplasia.
- Surgical intervention was possible in two cases, but percutaneous treatment was unsuitable in one due to valve anatomy.
- The condition may be underrecognized as a cause of primary mitral regurgitation in adults.

## Abstract

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.