The effects of interventional mitral valve repair using the MitraClip System on the results of pulmonary function testing, pulmonary pressure and diffusing capacity of the lung

Abstract

Background: The study analyzes changes in lung function, pulmonary pressure and diffusing capacity of the lung in patients with mitral valve regurgitation (MR) treated by MitraClip implantation.

Methods: A total of 43 patients (19 women and 24 men with an average age of 78.0 +/- 6.6 years) who were able to perform pulmonary function testing including diffusing capacity of the lung for carbon monoxide (DLCO), vital capacity (VC), total lung capacity (TLC), residual volume (RV) and forced expiratory volume in 1 s (FEV1) before and 6 weeks after MitraClip implantation participated in this study. Furthermore, clinical and echocardiographic parameters including systolic pulmonary artery pressure (sPAP), left ventricular ejection fraction (LVEF) and left atrial diameter (LAD) measurements were recorded in all patients.

Results: The procedure was performed successfully in all 43 patients leading to a reduction of MR in 97.7% of cases. One patient died on day 4 after the intervention most likely due to pulmonary artery embolism. Six weeks after the implantation 79.1% of patients showed a MR of at most mild to moderate. Furthermore, we could demonstrate a significant reduction of systolic pulmonary artery pressure during follow-up (from 48.8 +/- 11.4 mmHg to 42.9 +/- 9.0 mmHg (t(41) = - 2.6, p = 0.01). However, no changes in LVEF were detected. Comparing pre and post implant lung function tests, no significant alterations were seen for VC, TLC, DLCO and FEV1. Though, in a subgroup of patients with moderate to severe preexisting deterioration of DLCO at the baseline (max. 50%) the MitraClip procedure resulted in a significant improvement in DLCO (37.8% +/- 9.0 to 41.6% +/- 10.0, p < 0.001).

Conclusions: Treatment of MR with the MitraClip system successfully reduces MR severity in the vast majority of patients. Consecutively, a reduction in pulmonary pressure could be observed, however no changes in LVEF were obvious. Lung function tests remained unaltered during follow-up. However, in a subgroup of patients with severe preexisting deterioration of DLCO the MitraClip procedure resulted in a significant improvement in DLCO.