Prevalence, mechanisms, and prognostic impact of dynamic mitral regurgitation assessed by isometric handgrip exercise.

Abstract

The extent of mitral regurgitation (MR) may vary depending on the haemodynamic situation; thus, exercise testing plays an important role in assessing the haemodynamic relevance of MR. We aim to assess prevalence, mechanisms, and prognostic impact of exercise-induced changes in MR in patients with degenerative MR (DegMR) and functional MR (FMR). We enrolled 367 patients with at least mild MR who underwent standardized echocardiography at rest and during handgrip exercise. Handgrip exercise led to an increase in MR by one grade or more in 19% of DegMR and 28% of FMR patients. In FMR, patients with exercise-induced increases in MR, handgrip exercise led to a reduction in left ventricular stroke volume index, being maintained in DegMR patients. Exercise-induced changes in systolic pulmonary artery pressure were linked to changes in effective regurgitant orifice area (DegMR: r = 0.456; P < 0.001; FMR: r = 0.326; P < 0.001). Thus, 26% of patients with DegMR and FMR developed pulmonary hypertension during exercise. In both cohorts, a significant proportion of patients with non-severe MR at rest and exercise-induced severe MR underwent mitral valve surgery/intervention during follow-up. In FMR patients (but not in DegMR patients), early mitral valve surgery/intervention was independently associated with lower event rates during follow-up [0.177 (0.027-0.643); P = 0.025]. Handgrip exercise echocardiography provides important information regarding the dynamic nature of MR, exercise-induced changes in left ventricular function, and pulmonary circulation with subsequent consequences for further therapeutic decision making. Thus, it should be considered as a diagnostic tool in symptomatic patients with non-severe MR at rest.