Association between abdominal fat and mortality in patients undergoing cardiovascular surgery.

Abstract Background Obesity is associated with reduced postoperative mortality in patients undergoing cardiovascular surgery. However, body mass index cannot differentiate abdominal fat composition. This study evaluated the relationships between total abdominal, subcutaneous, and visceral fat composition and postoperative mortality in East Asian patients undergoing cardiovascular surgery. Methods Adult patients who underwent cardiovascular surgery between October 2004 and December 2016 were retrospectively included. Total, subcutaneous and visceral fat areas were measured from cross-sectional computed tomography images. The relationships between each fat composition and mortality were evaluated. Results A total of 3,661 patients were analyzed, and overall mortality was 19.9% (729 died) during the 4.6 year median follow-up period. The risks of all-cause and cardiac-cause mortality decreased as subcutaneous fat composition increased (adjusted hazard ratio [aHR], 0.997; 95% confidence interval [CI], 0.994–1.000 and aHR, 0.994; 95% CI, 0.989–0.999; P = .02 and = .01, respectively). No association was detected between the total and visceral fat area and mortality. Conclusions Reduced abdominal subcutaneous fat, but not the total or visceral fat composition was associated with higher all-cause and cardiac-cause mortality after cardiovascular surgery in East Asian patients, consisting mainly of normal or overweight patients.