164 Degenerative Mitral Regurgitation Severity Changes During Exercise Echocardiography

Abstract

Recent 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. Resting 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 (ERO P ) and the quantitative Doppler (ERO D ) methods. Systolic pulmonary arterial pressure (PAP) was derived from the peak regurgitant tricuspid pressure gradient. At rest, ERO D was greater than ERO P (52±16mm 2 vs. 31±17mm 2 , p<0.01) and were well correlated (r=0.65, p=0.004). During exercise, ERO P and ERO D increase in 71%, 54% and 54% of patients, respectively and there were good correlations between exercise ERO P and ERO D (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 ERO P and ERO D (r=0.33, p=0.04 and r=0.44, p=0.004). Moreover, patients with exercise peak PAP>60mmHg had higher exercise ERO P (33±21mm 2 vs. 45±22mm 2 , p=0.04) and ERO D (49±20 vs. 69±27mm 2 , p=0.005) and higher exercise-induced change in in ERO D (-2.7±17 vs. 12±18 mm 2 , p=0.006). After adjustment for age, sex and resting PAP, exercise-induced changes in ERO D remained associated with changes in PAP (β=0.22, p=0.033) As 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.