Use of Pre-operative Global Longitudinal Strain to Predict Post-operative Left Ventricular Dysfunction in Mitral Regurgitation Surgery

Overview

Primary mitral regurgitation (MR) is the second most frequent valve disease requiring surgery and it is important to identify patients whose outcome could be improved with surgery by considering the risks and benefits. The current guidelines recommend surgery in patients with symptomatic severe mitral regurgitation or in asymptomatic patients who develop early signs of left ventricular (LV) dysfunction as a result of the MR. However, it remains difficult to determine optimal timing for surgery with the current guidelines. Early-stage LV dysfunction with normal LVEF predicts post-operative LV decompensation and poor prognosis and longitudinal myocardial function is suitable for detection of minor myocardial damage in patients with MR. Thus, inestigators want to study the value of LV global longitudinal strain (GLS) to predict postoperative LV dysfunction in patients with chronic severe MR and preserved pre-operative LVEF. The principal aim is to prove that the optimal timing for surgery, in asymptomatic chronic severe primary MR with preserved LVEF, is before GLS alteration, and that investigators should not wait for LV dilatation of dysfunction.

Primary mitral regurgitation (MR) is the second most frequent valve disease requiring surgery. In these patients, mitral repair is associated with excellent outcomes in terms of post-operative left ventricular (LV) function, and long-term survival when performed before the onset of severe symptoms, LV dysfunction or dilatation, pulmonary hypertension, and atrial fibrillation. Thus, it is important to identify patients whose outcome could be improved with surgery by considering the risks and benefits. The current guidelines recommend surgery in patients with symptomatic severe mitral regurgitation or in asymptomatic patients who develop early signs of left ventricular (LV) dysfunction as a result of the MR. LV dysfunction has been defined as LV ejection fraction (EF) 30% to 60% and/or LV end-systolic dimension (ESD) up to 45 mm. However, it remains difficult to determine optimal timing for surgery with the current guidelines. LVEF and LVESD, parameters proposed in the guideline, are difficult to interpret due to the influence of hemodynamic parameters of MR. In asymptomatic patients who consider undergoing surgery, LVESD is rarely more than 45 mm. In addition, LVEF in patients with severe MR often remains normal or higher, and subclinical LV dysfunction might be masked due to MR lowering of LV afterload. Early-stage LV dysfunction with normal LVEF predicts post-operative LV decompensation and poor prognosis. Therefore, it is a great challenge to identify potential LV dysfunction at an early stage and to perform surgery to prevent the development of irreversible LV dysfunction in patients with chronic severe MR. Longitudinal myocardial function has been considered more sensitive than radial function and is therefore suitable for detection of minor myocardial damage in patients with MR. A 2017 study proved that pre-operative GLS ≤ -18.4% can predict a preserved post-operative LVEF \>50%. Therefore, invetsigators want to study the value of LV global longitudinal strain (GLS) to predict postoperative LV dysfunction in patients with chronic severe MR and preserved pre-operative LVEF. The principal aim is to prove that the optimal timing for surgery, in asymptomatic chronic severe primary MR with preserved LVEF, is before GLS alteration, and that investigators should not wait for LV dilatation of dysfunction. Thus, investigators will recruit patients before surgery, measuring GLS during pre-operative conventional echography, and follow-up patients at 8 days, 1 month and 6 months to determine whether LVEF is preserved or not.