The contribution of exercise echocardiography in primary asymptomatic mitral regurgitation (MR) remains debated. The aim of this study was to gain evidence regarding its usefulness in this setting and to investigate the prognostic value of peak exercise systolic pulmonary artery pressure (SPAP).
One hundred seventy-seven patients (mean age, 56 ± 13 years; 69% men) with moderate to severe (grade 3+) or severe (grade 4+) degenerative MR and preserved left ventricular ejection fraction, in sinus rhythm, referred for clinically indicated exercise echocardiography were identified. The end point, MR-related events, was a composite of all-cause death or occurrence of symptoms, heart failure, atrial fibrillation, left ventricular ejection fraction < 60%, left ventricular end-systolic diameter ≥ 45 mm, or resting SPAP > 50 mm Hg.
At rest, effective regurgitant orifice area was 48 ± 16 mm ² , regurgitant volume 74 ± 26 mL, and SPAP 32 ± 7 mm Hg, and MR was severe in 138 patients (78%). Peak exercise SPAP was 55 ± 10 mm Hg. Positive results on exercise testing motivated surgery in 26 patients, 11 underwent prophylactic surgery, 10 were lost to follow-up, and 130 were included in the outcome analysis. During a follow-up period of 19 ± 7 months, 31 MR-related events (24%) were reported. Peak exercise SPAP was predictive of outcomes in univariate analysis (P = .01) and after adjustment for age, gender, MR severity, and resting SPAP (P < .05). Peak exercise SPAP ≥ 50 mm Hg was associated with worse event-free survival (hazard ratio, 5.24; 95% CI, 1.77-15.53; P = .003), but not the threshold of ≥60 mm Hg proposed in previous guidelines (hazard ratio, 1.70; 95% CI, 0.71-4.03; P = .24).
The present findings support the use of exercise echocardiography for risk stratification in patients with asymptomatic primary MR and suggest a lower peak exercise SPAP threshold (50 mm Hg) than previously recommended to define the timing of intervention. Prospective studies are needed to confirm these findings.