Is concomitant surgery for moderate functional mitral regurgitation indicated during aortic valve replacement for aortic stenosis? A systematic review and evidence-based recommendations.

BACKGROUND: Mitral regurgitation (MR) is associated with poor clinical outcomes. Functional MR is often associated with aortic stenosis (AS) and may resolve after aortic valve replacement (AVR). The objective of this study was to derive evidence-based recommendations regarding surgical intervention for moderate functional MR at the time of AVR for AS.
METHODS: An exhaustive literature search strategy including Medline, Embase, the Cochrane library, and meeting abstracts was performed. Studies meeting inclusion criteria were critically appraised and data pooled according to accepted meta-analysis techniques. The primary outcome was change in moderate MR after isolated AVR. Secondary outcomes were the impact of functional MR on survival and identifying factors that predict progression of MR, in patients undergoing isolated AVR for AS.
RESULTS: Thirteen nonrandomized studies including 2113 patients were reviewed. A total of 268 patients had preoperative moderate functional MR and AS. All studies were appraised as poor methodological quality. After isolated AVR a trend toward improvement in MR was observed. Left ventricular dysfunction, left atrial enlargement, and atrial fibrillation were associated with progression of MR after AVR. However, the impact of residual MR on late survival was not consistent.
CONCLUSION: Pooling current evidence provided inconclusive evidence to make clinical practice recommendations for or against routine surgical intervention of moderate MR at the time of AVR for AS. The incidence of this pathology makes further clinical trial studies warranted.