Postoperative loss of skeletal muscle mass, complications and quality of life in patients undergoing cardiac surgery

Objective

The objective of this study was to describe postoperative undernutrition in terms of postoperative losses of appendicular skeletal muscle mass (ASMM) with respect to complications, quality of life, readmission, and 1-y mortality after cardiac surgery.

Methods

Patients undergoing cardiac surgery were prospectively followed. ASMM was measured 2 wk before and 2 mo after surgery using dual-energy X-ray absorptiometry. ASMM consists of arm skeletal muscle mass (SMM) and leg SMM. The association between ≥5% of ASMM decrease and postoperative outcome was analyzed using the chi-square test. A similar approach was used to analyze arm SMM and leg SMM decreases separately.

Results

Twenty-nine patients were included (23 male, 34.5% ≥65 y old). Postoperatively, seven patients (24.1%) lost ≥5% ASMM. When analyzed separately, a ≥5% decrease in leg SMM was associated with a decrease in experienced vitality (odds ratio 13.0, 95% confidence interval 1.32-128.11, P = 0.03). In contrast, a ≥5% loss of arm SMM was associated with fewer in-hospital complications (odds ratio 0.20, 95% confidence interval 0.04-0.98, P = 0.04). These patients were characterized by a higher preoperative fat-free mass index (kilograms per meter squared; P = 0.01).

Conclusions

The results suggest that a preoperatively higher fat-free mass index indicates better ability to cope with operative stress, resulting in fewer complications. In addition, postoperative loss of muscle mass was associated with decreased vitality. We advocate further research investigating the effect of preoperative and postoperative nutritional intervention combined with physical exercise programs to increase lean body mass and thereby improve postoperative recovery after cardiac surgery.