Left Ventricular Outflow Tract Obstruction after Mechanical Mitral Valve Replacement

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.