Extent and determinants of dynamic mitral regurgitation unmasked by handgrip exercise in patients with primary mitral regurgitation

Abstract

Abstract Background Bicycle exercise is the exercise modality of choice to unmask the dynamic nature of mitral regurgitation (MR). Handgrip exercise may serve as alternative exercise intervention, as it can be performed physically accomplished by the majority of patients. Until now, there are only scarce data on the prevalence and magnitude of dynamic MR during handgrip exercise. Purpose To assess extent and predictors of exercise-induced dynamic MR during handgrip exercise in patients with primary MR. Methods We prospectively included patients with primary MR and at least mild severity that underwent echocardiography at rest and during three minutes of handgrip exercise according to a standardized protocol. Results The final patient cohort included 166 patients. Mean age was 72±12 years, 57% were female and 53% had atrial fibrillation. At rest, MR severity was graded as mild in 57% of patients, moderate MR in 27% and severe in 16%. Handgrip exercise led to an increase in at least one grade in MR severity in 31 patients (19%), while 15 patients (9%) experienced a decrease of MR severity (Fig. 1B). Twenty patients (14%) of those with non-severe MR at rest, developed severe MR during handgrip exercise (Fig. 1B). According to a pre-defined cutoff of increase in effective orifice regurgitant area (EROA) >10 mm2 during exercise, 19% of patients revealed a marked exercise-induced increase in MR, irrespective of the severity of MR at rest. Patients with marked exercise-induced increases in MR severity (EROA >10 mm2) had elevated left- (53±22ml/m2 vs. 44±19ml/m2; p=0.036), and right atrial volumes (43±19ml/m2 vs. 34±18ml/m2; p=0.014), more often pathology of the anterior mitral leaflet (e.g. prolapse; flail leaflet) (65% vs. 33%; p<0.001), and increased mitral annulus diameter (38±5mm vs. 36±4mm; p=0.003). The exercise-induced changes in EROA correlated with changes in estimated systolic pulmonary pressure from rest to exercise (r=0.438 (0.287 to 0.568); p<0.001) (Fig. 1C). Conclusion(s) In patients with primary MR, handgrip echocardiography unmasks marked exercise-induced increases of MR severity in every fifth patient independent of the severity at rest. A relevant number of patients with non-severe MR at rest developed severe MR during exercise. Dynamic MR is associated with bi-atrial dilatation, increased mitral annulus diameter, and pathology of the anterior mitral valve leaflet. Moreover, changes in MR severity during handgrip exercise correlate with changes in pulmonary pressures. Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): This work was supported by the Forschungskommission of the Medical Faculty of the Heinrich Heine University Düsseldorf Maximilian Spieker for a Clinician Scientist Track.