Preoperative left atrial volume index is associated with postoperative outcomes in mitral valve repair for chronic mitral regurgitation

Objective: To assess determinants of left atrial reverse remodeling after mitral valve repair and to evaluate the impact of preoperative left atrial volume on postoperative outcomes. Methods: We reviewed the records of 720 patients who underwent mitral valve repair from September 2008 to July 2015 and had preoperative measurement of left atrial volume index. We analyzed the association of preoperative left atrial volume index on early and late outcomes, and determined which baseline characteristics are associated with left atrial reverse remodeling, as measured by changes in left atrial volume index in 512 patients who had at least 1 postoperative measurement. Results: The median (interquartile range) preoperative left atrial volume index was 54.0 (44.0-66.0) mL/m(2). Preoperative left atrial volume index, age, body mass index, and atrial fibrillation were independently associated with the degree of left atrial reverse remodeling over the follow-up period. Reverse remodeling was greatest in patients with higher baseline left atrial volume index (P < .001), but less reverse remodeling was observed in patients with advanced age (P < .001), preoperative atrial fibrillation (P < .001), and extreme values of body mass index (P = .004), although these effects were moderately attenuated when limiting the analysis to 6-month follow-up. Secondary analysis demonstrated marginally significant effects of preoperative left atrial volume index on risks of early postoperative atrial fibrillation (P = .030) and late mortality (P = .077) after adjusting for age and sex. Conclusions: In patients with degenerative mitral valve regurgitation who had mitral valve repair, preoperative left atrial volume index was associated with extent of left atrial reverse remodeling, risk of early postoperative atrial fibrillation, and late mortality. The majority of reverse remodeling occurs within the first month after operation and is greatest in younger patients.