MitraClip improves cardiopulmonary exercise test in patients with systolic heart failure and functional mitral regurgitation

AIMS: The aim of this study is to evaluate changes in cardiopulmonary exercise test (CPET) after percutaneous mitral valve repair (PMVR) with MitraClip in patients with heart failure with reduced ejection fraction who are potentially candidates for heart transplantation or destination left ventricular assist device. METHODS AND RESULTS: Prospective registry of all consecutive patients with heart failure with reduced ejection fraction and functional mitral regurgitation (MR) underwent elective PMVR between October 2015 and March 2018 in our institution. Patients with preserved or mid‐range left ventricular ejection fraction (>40%), advanced age (>75 years old), or severe co‐morbidities (end‐stage organ damage) were not included. Treadmill exercise testing with respiratory gas exchange analysis was carried out in 11 patients (male, 72.7%; median age, 67 years old) within the month prior to the procedure and at 6 month follow‐up. PMVR was successfully performed in all patients. At 6 month follow‐up, PMVR was associated with an improvement in New York Heart Association functional class (P = 0.021) and a reduction in MR severity (P = 0.013) and N‐terminal pro‐brain natriuretic peptide levels (2805 [1878–5022] vs. 1485 [654–3032] pg/mL; P = 0.012). All patients completed pre‐procedural and post‐procedural CPET, and all the studies showed a respiratory exchange ratio ≥1 and were consistent with sufficient exercise effort. Compared with pre‐procedural CPET, patients showed a significant increase in exercise time (295 [110–335] vs. 405 [261–540] s; P = 0.047), VO(2) (9.8 [9.1–13.4] vs. 13.5 [12.1–16.8] mL/kg/min; P = 0.033), ventilatory anaerobic threshold (510 [430–950] vs. 850 [670–1070] mL/kg/min; P = 0.033), peak O(2) pulse (7.2 [4.3–8.6] vs. 8.3 [6.2–11.8] mL/beat; P = 0.033), and workload (5 [3–6] vs. 6 [5–8] metabolic equivalents; P = 0.049). CONCLUSIONS: Percutaneous mitral valve repair with MitraClip was associated with an enhancement in cardiopulmonary performance in patients with systolic heart failure and secondary MR.