Introduction

Mitral valve disease are treated with mitral valve replacement when the valve is not repairable. The importance of preserving the subvalvular apparatus has been demonstrated in experimental and clinical studies, and consensus exists around attempting to preserve the native chordal apparatus [1,2]. In this frame, whether the preservation of the subvalvular apparatus should involve both the anterior and posterior leaflets’ versus the posterior leaflet’s alone remains a matter of scientific debate. Regardless, the spared subvalvular apparatus should neither interfere with the implanted valve nor cause a substrate for left ventricular outflow tract obstruction [3]. We present a case of severe, bio prosthetic mitral valve stenosis whose etiology was related to the preserved native anterior mitral valve leaflet.

Case Report

A 65-year-old male was admitted to our hospital with worsening shortness of breath. Their medical history included mitral valve replacement with a 29 mm Carpenter Edwards pericardial prosthesis and concomitant coronary artery bypass graft to the right coronary artery 15 years before. Additionally, the patient had a history of ST elevation myocardial infarction with percutaneous coronary intervention to the left anterior descending and circumflex coronary arteries 3 years before.  The  patient  was now hospitalized with acute hypoxic respiratory failure and evidence of pulmonary edema. Echocardiography showed severe mitral stenosis with peak and mean gradients of 17 and 12 mmHg, respectively. The mitral valve area was 1.22 cm2. Transesophageal echocardiography revealed that only one of the three commissures opened during diastole (Figure 1). Left ventricular ejection fraction was 35%. A redo median sternotomy was performed and after establishment of cardiopulmonary bypass, the left atrium  was accessed through the interatrial groove. Upon inspection of the malfunctioning prosthesis, we found that both the anterior and posterior leaflets had been left in situ during the prior surgery.  Therefore, large portions of the native anterior mitral valve leaflet were wrapped around two of the commissural posts (Figure 2). The encircling of the commissural posts by the native anterior mitral leaflet was deemed responsible for the inadequate opening of the two commissures. The fusion of the commissure posts with the native mitral valve leaflet and the preserved subvalvular apparatus made explanation technically challenging. After explanation was completed, a 29 mm Edwards Mitris Resilia valve was successfully implanted. The patient had a prolonged postoperative stay due to delayed respiratory recovery and postoperative delirium. The patient was discharged home 17 days after surgery and remains asymptomatic at latest follow-up.