The acute haemodynamic effect of the MitraClip therapy: afterload mismatch evaluation in functional mitral regurgitation

Abstract

Background: Despite the safety and the efficacy of the MitraClip percutaneous mitral valve repair (MVR) have been assessed in randomized international trials, limited data on the acute hemodynamic impact are available. Afterload mismatch, defined as an impairment of left ventricular function after correction of mitral regurgitation (MR), is a known complication after surgery. The aim of this study is to investigate the incidence and the prognostic role of afterload mismatch in patients undergoing MitraClip therapy. Methods ans results: We retrospectively analyzed 76 consecutive patients, affected by functional MR (fMR) and submitted to MitraClip therapy. 3 patients with post-procedural MR≥3+ were excluded from the analysis. The remaining 73 patients were assigned to two groups according to the occurrence of the afterload mismatch. Afterload mismatch was defined as an acute EF reduction of -28% after MitraClip therapy, compared to the baseline assessment (this value represents the first quartile in the distribution of the change of the EF; baseline LVEF mean value 27±9). Afterload mismatch was observed in 19 pts (26%) in the early postoperative period (LVEF 16±7 in group with afterload mismatch (AM+) vs 28±10 in group without afterload mismatch (AM-); p<0,0001). At univariate analysis preoperative EDD (71 vs 67 mm; P = 0,022) and ESD (57 vs 53 mm; P = 0,042) were significantly higher in AM+ as compared to AM-. AM+ patients experienced an increased incidence of right ventricular dysfunction (68% of pts vs 31% of pts; P= 0,049) and pulmonary hypertension (49 vs 40mmHg; P = 0,0009). No difference in the use of inotropes (84% of pts vs 83% of pts; P= 0,92), in acute renal failure (16% vs 28% of pts; P= 0,29) and in length of stay in intensive care unit (22,4 vs 23,7 hours P= 0,92) was recorded among the two groups. Patients in the AM+ group showed a significant recovery of LVEF (p<0,0001) before hospital discharge, without any significant differences as compared to the AM-group (31% vs 33%, p=0,65). Long term survival was comparable between the two groups (81,2±9,9% vs 75,2±8,7%; P = 0,44). Conclusion: The reduction of MR by MitraClip therapy can be associated with afterload mismatch, especially in patients with preoperative increased left ventricular diastolic and systolic diameters. However afterload mismatch is reversible, without long-term prognostic implications.