Papillary Muscle Approximation vs. Restrictive Annuloplasty for Severe Ischemic MR
What is the benefit of papillary muscle surgery on long-term clinical outcomes of patients with ischemic mitral regurgitation (MR)?
Ninety-six patients with severe ischemic MR were randomized to either undersizing restrictive mitral annuloplasty (RA) or papillary muscle approximation with undersizing restrictive mitral annuloplasty (PMA), associated with complete surgical myocardial revascularization. The primary endpoint was change in left ventricular end-diastolic diameter (LVEDD) after 5 years, measured as the absolute difference from baseline, evaluated by paired Student t-tests. Secondary endpoints included changes in echocardiographic parameters, overall mortality, the composite cardiac endpoint (major adverse cardiac and cerebrovascular events [MACCE]), and quality of life (QOL) during the 5-year follow-up.
At 5 years, mean LVEDD was 56.5 ± 5.7 mm with PMA versus 60.6 ± 4.6 mm with RA (mean change from baseline -5.8 ± 4.1 mm and -0.2 ± 2.3 mm, respectively; p < 0.001). Ejection fraction was 44.1 ± 6% in the PMA versus 39.9 ± 3.9% in the RA group (mean change from baseline 8.8 ± 5.9% and 2.5 ± 4.3%, respectively; p < 0.001). There was no statistically significant difference in mortality at 5 years, but freedom from MACCE favored PMA in the last year of follow-up. PMA significantly reduced tenting height, tenting area, and interpapillary distance soon after surgery and long-term and significantly lowered moderate-to-severe MR recurrence. No differences were found in QOL measures.
The authors concluded that compared with RA only, papillary muscle approximation with undersizing RA exerted a long-term beneficial effect on left ventricular remodeling and more effectively restored the mitral valve geometric configuration in ischemic MR.
This randomized study reports the superiority of papillary muscle approximation with undersizing RA over standard annuloplasty alone in terms of ventricular geometry, remodeling, and function in ischemic MR. However, this benefit did not produce a significant survival advantage. Additional studies are indicated to directly compare a complete repair strategy, including both PMA and RA versus chordal-sparing mitral replacement to define optimal strategy for patients with severe ischemic MR. The data presented here will help guide the decision-making process for the surgical strategy in ischemic MR and patient expectations for surgery in these patients.
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