Relation of Residual Mitral Regurgitation Despite Elevated Mitral Gradients to Risk of Heart Failure Hospitalization After MitraClip Repair

Abstract

Achieving minimal residual mitral regurgitation (MR) after percutaneous MitraClip repair is limited by iatrogenic mitral stenosis. It is unknown whether allowing moderately elevated postprocedural mean mitral gradients (MMGs) to achieve < moderate residual MR is preferable to moderate residual regurgitation. Patients with less-than-moderate residual MR but a MMG of ≥5 mm Hg (Group 1) were compared with patients with moderate residual MR (Group 2). The primary end point was heart failure hospitalization. Secondary end points included mortality, subsequent mitral valve surgery, and MR at 1 year. Seventy-eight patients were included in the study. Group 1 included 48 patients (median MMG 6, interquartile range 5-6 mm Hg). Group 2 included 30 patients (median MMG 3.5, interquartile range 2-5 mm Hg). Age, baseline MR severity, and type of MR were not different between groups. Freedom from heart failure hospitalization at 1 year was 91.2 ± 4.2% in Group 1 versus 70.8 ± 8.7% in Group 2 (p = 0.021). Achieved differences in MR reduction between groups persisted at 1 year (p = 0.007). Survival was not different (p = 0.402), and subsequent mitral valve surgery occurred in 4 of 48 (8%) and in 4 of 30 patients (13%) in Group 1 and Group 2, respectively (p = 0.476). By multivariate Cox regression analysis, less-than-moderate residual MR, despite moderately elevated mitral gradients, was associated with a hazard ratio of 0.21 (95% confidence interval 0.04 to 0.96) for subsequent heart failure hospitalization (p = 0.044). In conclusion, patients with less-than-moderate residual MR despite a MMG of ≥5 had a 79% reduction in hazard for subsequent heart failure hospitalization compared with patients with moderate residual MR.