164 Degenerative Mitral Regurgitation Severity Changes During Exercise Echocardiography

IntroductionRecent studies revealed that mitral regurgitation (MR) severity may change during exercise in patients with functional MR. Significant exercise-induced increases in MR is associated with poor outcome. By contrast, changes in MR severity during exercise remain undetermined in patients with degenerative MR.Method and resultsResting and symptom-limited semi-supine bicycle exercise Doppler-echocardiography were performed in 66 consecutive patients (61±15 yrs and 55% of male) with moderate to severe degenerative MR. MR severity was evaluated, at rest and during exercise using effective regurgitant orifice (ERO) calculated with the PISA (EROP) and the quantitative Doppler (EROD) methods. Systolic pulmonary arterial pressure (PAP) was derived from the peak regurgitant tricuspid pressure gradient. At rest, EROD was greater than EROP (52±16mm2 vs. 31±17mm2, p<0.01) and were well correlated (r=0.65, p=0.004). During exercise, EROP and EROD increase in 71%, 54% and 54% of patients, respectively and there were good correlations between exercise EROP and EROD (r=0.73, p<0.01). Systolic PAP also increased during exercise (from 29±9 to 52±16mmHg, p<0.01) and changes in PAP during test were correlated with changes in EROP and EROD (r=0.33, p=0.04 and r=0.44, p=0.004). Moreover, patients with exercise peak PAP>60mmHg had higher exercise EROP (33±21mm2 vs. 45±22mm2, p=0.04) and EROD (49±20 vs. 69±27mm2, p=0.005) and higher exercise-induced change in in EROD (-2.7±17 vs. 12±18 mm2, p=0.006). After adjustment for age, sex and resting PAP, exercise-induced changes in EROD remained associated with changes in PAP (β=0.22, p=0.033)ConclusionAs in functional MR, degenerative MR can be dynamic and increases during exercise in >50% of patients. Changes in MR severity are associated with exerciseinduced changes in systolic PAP, suggesting a potential impact on outcome. Further studies are needed to determine whether exercise-induced increase in MR has prognostic importance