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Exercise Pulmonary Hypertension in Asymptomatic Degenerative Mitral Regurgitation

Background— Current guidelines recommend mitral valve surgery for asymptomatic patients with severe degenerative mitral regurgitation and preserved left ventricular systolic function when exercise pulmonary hypertension (PHT) is present. However, the determinants of exercise PHT have not been evaluated. The aim of this study was to identify the echocardiographic predictors of exercise PHT and the impact on symptoms. Methods and Results— Comprehensive resting and exercise transthoracic echocardiography was performed in 78 consecutive patients (age, 61±13 years; 56% men) with at least moderate degenerative mitral regurgitation (effective regurgitant orifice area =43±20 mm2; regurgitant volume =71±27 mL). Exercise PHT was defined as a systolic pulmonary arterial pressure (SPAP) >60 mm Hg. Exercise PHT was present in 46% patients. In multivariable analysis, exercise effective regurgitant orifice was an independent determinant of exercise SPAP (P<0.0001) and exercise PHT (P=0.002). Resting PHT and exercise PHT were associated with markedly reduced 2-year symptom-free survival (36±14% versus 59±7%, P=0.04; 35±8% versus 75±7%, P<0.0001). After adjustment, although the impact of resting PHT was no longer significant, exercise PHT was identified as an independent predictor of the occurrence of symptoms (hazard ratio=3.4; P=0.002). Receiver-operating characteristics curves revealed that exercise PHT (SPAP >56 mm Hg) was more accurate than resting PHT (SPAP >36 mm Hg) in predicting the occurrence of symptoms during follow-up (P=0.032). Conclusions— Exercise PHT is frequent in patients with asymptomatic degenerative mitral regurgitation. Exercise mitral regurgitation severity is a strong independent predictor of both exercise SPAP and exercise PHT. Exercise PHT is associated with markedly low 2-year symptom-free survival, emphasizing the use of exercise echocardiography. An exercise SPAP >56 mm Hg accurately predicts the occurrence of symptoms.