Is subvalvular repair worthwhile in severe ischemic mitral regurgitation? Subanalysis of the Papillary Muscle Approximation trial.

OBJECTIVE: The symmetry of mitral valve tethering and regional left ventricle wall dysfunction are reported to play a fundamental role in the outcomes and long-term durability of surgical repair in ischemic mitral regurgitation (IMR). We recently demonstrated in a randomized clinical trial (the Papillary Muscle Approximation trial) the superiority of papillary muscle approximation (PMA) in combination with standard restrictive annuloplasty (RA) in severe IMR over annuloplasty alone in terms of adverse left ventricular remodeling and mitral regurgitation (MR) recurrence. This approach, however, failed to produce a survival advantage and was still plagued by a high incidence of reoperation. We therefore performed a subanalysis of the PMA trial on the basis of preoperative parameters to elucidate the value of subvalvular surgery in certain subcategories of patients with the aim of creating a decisional algorithm on the best operative strategy.

METHODS: We performed a subanalysis of PMA trial, evaluating 96 patients with severe IMR and eligible for myocardial revascularization randomized to PMA + RA (n = 48) versus RA alone (n = 48) in association with coronary artery bypass grafting. Endpoints included left ventricular remodeling, MR recurrence, overall mortality, reoperation, and a composite cardiac endpoint (cardiac death, stroke, reintervention, hospitalization for heart failure, or New York Heart Association class worsening). Stratification variables were preoperative symmetry of mitral valve tethering and regional wall motion abnormality.

RESULTS: PMA improved ventricular remodeling and recurrence of MR in both preoperative symmetric and asymmetric tethering and in case of inferior wall dyskinesia but did not produce an additional benefit in anterolateral wall dysfunction.

CONCLUSIONS: Preoperative symmetric and asymmetric tethering and isolated inferior wall dyskinesia are an indication for subvalvular apparatus surgery in IMR.