Assessing proportionate and disproportionate functional mitral regurgitation with individualized thresholds

Area of Science:

• Cardiology
• Echocardiography
• Heart Failure

Background:

• Functional mitral regurgitation (FMR) is common in heart failure with reduced ejection fraction.
• Assessing FMR proportionality has been challenging due to a lack of standardized methods and prognostic data.
• Existing guidelines have limitations in accurately stratifying risk based on FMR severity.

Purpose of the Study:

• To evaluate the prognostic value of an individualized method for assessing FMR proportionality.
• To determine if this individualized approach offers superior risk stratification compared to current guidelines.
• To investigate the association between disproportionate FMR and all-cause mortality.

Main Methods:

• Retrospective analysis of 572 patients with at least mild FMR and LVEF <50% on medical therapy.
• Utilized a novel equation to determine individualized theoretical FMR thresholds.
• Categorized patients into non-severe, proportionate, and disproportionate FMR groups.
• Assessed all-cause mortality as the primary endpoint over a median follow-up of 3.8 years.

Main Results:

• Disproportionate FMR was independently associated with increased all-cause mortality (aHR: 1.785, P=0.001).
• The FMR proportionality concept demonstrated superior discriminative power (C-statistic 0.639) compared to American (0.583) and European (0.584) guidelines.
• Incorporating FMR proportionality improved risk stratification by reclassifying patients into distinct risk subsets.

Conclusions:

• Disproportionate FMR is a significant independent predictor of mortality in patients with heart failure and reduced ejection fraction.
• An individualized method for assessing FMR proportionality enhances prognostic accuracy.
• This approach offers a valuable tool for refining risk stratification beyond current guideline recommendations.