Abstract 16916: Shortening of Pressure Half Time During Exercise as a Predictor for Exercise Capacity in Patients With Bileaflet Mitral Valve Replacement

Abstract

Introduction: In patients with mechanical mitral valve replacement (MVR), effective orifice area is fixed during dynamic exercise. Therefore, pressure half time (PHT) change during exercise might be mainly influence by exercise-induced left ventricular end-diastolic pressure raise. Hypothesis: We hypothesized that shortening of PHT during supine bicycle exercise would predict exercise capacity in patients with bileaflet mechanical MVR. Methods: Patients with isolated bileaflet MVR (n = 40) prospectively underwent symptom-limited supine bicycle exercise testing with Doppler echocardiography. Heart rate (HR), peak and mean transprosthetic gradient, PHT, and systolic pulmonary artery pressure (SPAP) were assessed at different stages of exercise. Changes in PHT during 25W and 50W exercise (ΔPHT-25W and ΔPHT-50W, respectively) were measured. Changes in HR during 25W and 50W exercise (ΔHR-25W and ΔHR-50W, respectively) were calculated. Results: There were significant negative correlations between exercise duration and ΔPHT-25W (r = -0.345, p = 0.032) or ΔPHT-50W (r = -0.369, p = 0.027) ( Figure A and B ). Exercise duration demonstrated independent significant correlation with both ΔPHT-25W (p = 0.018) and ΔPHT-50W (p = 0.006), even after adjusting for age, sex, and ΔHR-25W/50W, respectively. Conclusion: Degree of PHT shortening during 25W and 50W exercise predicted exercise capacity in patients with bileaflet mechanical MVR. More shortened PHT during exercise was associated with low exercise capacity, which might be associated with diastolic dysfunction resulted from exercise-induced left ventricular end-diastolic pressure raise.