Grant: Operating Grant

Mitral regurgitation (MR) is a frequent and serious cardiac disease that is characterized by a leak at the level of the mitral valve. When MR becomes severe, the only efficient treatment is to repair or replace the diseased valve. However, the optimal timing of this open-heart surgery remains uncertain and controversial. The current guidelines for clinical practice recommend waiting for the development of symptoms or cardiac chamber dysfunction to perform surgery, whereas some investigators believe that all patients with severe MR should be operated even if they have no symptoms or signs of cardiac dysfunction. In the current clinical practice, the patients are generally evaluated at rest, which does not necessarily represent the physiological conditions of the patient during his or her daily activities. In this large prospective follow-up study of >400 patients with at least moderate MR, we will perform a comprehensive evaluation of valve and cardiac function not only at rest but also during exercise. We believe that the indices of MR and cardiac function measured during exercise will provide important new information that will help the clinician to better predict the progression rate of the disease and thereby to better select the optimal timing for surgery. We will also determine whether or not patients with abdominal obesity have a more rapid progression of MR and associated cardiac dysfunction. This study is the first of its kind, as it will measure prospectively in a large cohort of patients: 1) MR severity at rest and exercise and its progression over time, 2) the patient's maximum exercise capacity; 3) several hormones produced by the heart muscle; 4) the metabolic abnormalities associated with abdominal obesity; and 5) the occurrence of adverse events (symptoms, deaths, heart failure etc.). The new knowledge generated by this study will contribute to improve the risk evaluation and the therapeutic management of the patients with this disease.