Left Ventricular Outflow Tract Obstruction after Mechanical Mitral Valve Replacement

Fathia Mghaieth Zghal; Manel Ben Halima; Bassem Rekik; Ali Bonkano; Abdeljelil Farhati; Sana Ouali; Selim Boudiche; Mohamed Sami Mourali

Fathia Mghaieth Zghal Rabta University Hospital of Tunis, Tunisia and University of Tunis El Manar, Faculty of Medicine, Tunis, Tunisia.
Manel Ben Halima Rabta University Hospital of Tunis, Tunisia and University of Tunis El Manar, Faculty of Medicine, Tunis, Tunisia.
Bassem Rekik Rabta University Hospital of Tunis, Tunisia and University of Tunis El Manar, Faculty of Medicine, Tunis, Tunisia.
Ali Bonkano Rabta University Hospital of Tunis, Tunisia.
Abdeljelil Farhati Rabta University Hospital of Tunis, Tunisia.
Sana Ouali Rabta University Hospital of Tunis, Tunisia and University of Tunis El Manar, Faculty of Medicine, Tunis, Tunisia.
Selim Boudiche Rabta University Hospital of Tunis, Tunisia and University of Tunis El Manar, Faculty of Medicine, Tunis, Tunisia.
Mohamed Sami Mourali Rabta University Hospital of Tunis, Tunisia and University of Tunis El Manar, Faculty of Medicine, Tunis, Tunisia.

Keywords: Heart valve prosthesis, left ventricular outflow obstruction, post-operative complication, cardiac surgery

Abstract

Background: Left ventricular outflow tract (LVOT) obstruction is a serious complication that can occur after various mitral-valves, surgical or percutaneous, interventions.

It was rarely described in mechanical mitral valve replacements.

Aim: To analyze a case of late LVOT obstruction after a mitral valve replacement by a low-profile mechanical prosthesis in the light of a review of the literature.

Case Presentation: A 48-year old woman, with a history of rheumatic mitral valve disease and mechanical mitral replacement by a hemi-disc valve 18 years ago, presented for a recent dyspnea. Echocardiography showed a narrowing of the LVOT, with anterior position of the mitral prosthesis, aorto-mitral annular angulation, septal thickening and remnant native sub-valvular tissue attached to the septum in the LVOT region. This resulted in LVOT obstruction with a peak gradient of 75 mmHg. The heart team opted for a redo surgery, but the surgical decision was refused by the patient.

Discussion: LVOT obstruction after mitral valve replacement was mainly related to preserved native mitral valve tissue, but we highlighted that other causes can contribute to it like septal thickening and anterior prosthetic position. Aorto-mitral annular angulation that was identified as a risk factor of LVOT obstruction after trans-catheter mitral valve replacements, should be, probably, also took into account and assessed pre-operatively in patients undergoing surgical mitral replacements.

Conclusion: LVOT obstruction can occur after mechanical mitral replacements event with low profile prosthesis. In patients with identified risk factors preservation mitral anterior leaflet should be avoided, and preservation of other native mitral tissue should be discussed.