Afterload mismatch after MitraClip insertion for functional mitral regurgitation

Area of Science:

• Cardiology
• Interventional Cardiology
• Cardiac Surgery

Background:

• Afterload mismatch, an acute decline in left ventricular function post-mitral surgery, is a significant concern for patients with low ejection fraction and functional mitral regurgitation (FMR).
• While MitraClip therapy's safety and efficacy are established, its acute hemodynamic effects, particularly concerning afterload mismatch, require further investigation.

Purpose of the Study:

• To determine the incidence and prognostic significance of afterload mismatch in patients with FMR undergoing MitraClip therapy.
• To analyze the acute hemodynamic effects and long-term outcomes associated with afterload mismatch post-MitraClip intervention.

Main Methods:

• A retrospective analysis of 73 patients with FMR treated with MitraClip between October 2008 and December 2012.
• Patients were categorized into two groups: those who developed afterload mismatch (AM+) and those who did not (AM-).
• Preoperative and postoperative echocardiographic parameters, including left ventricular ejection fraction (LVEF), and long-term survival were assessed.

Main Results:

• Afterload mismatch occurred in 26% of patients (19/73) in the early postoperative period.
• The AM+ group exhibited larger preoperative end-diastolic and end-systolic diameters, increased right ventricular dysfunction (68% vs. 31%), and higher pulmonary hypertension (49 ± 10 vs. 40 ± 10 mm Hg).
• LVEF normalized before discharge in both groups, and long-term survival was comparable (p = 0.44). However, a postoperative LVEF <17% was linked to higher long-term mortality (p = 0.048).

Conclusions:

• MitraClip therapy for FMR can induce transient afterload mismatch.
• This hemodynamic complication does not appear to have long-term prognostic implications for survival.
• Close monitoring of LVEF in the early postoperative period is crucial, as critically low levels may predict long-term mortality.