Challenging BMI: Fat Mass Indices for Improved Postoperative Risk Prediction in CABG Patients

ABSTRACT Background This study investigated the effect of preoperative fat mass index (FMI), fat-free mass index (FFMI), fat mass ratio (FMR) and fat-free mass ratio (FFMR) on postoperative morbidity and mortality in coronary artery bypass grafting (CABG) patients. Methods 120 patients were included in this prospective study. The patients’ FMI, FFMI, FMR and FFMR were evaluated preoperatively along with other clinically significant data. The postoperative morbidities were recorded. Receiver operating characteristic (ROC) Curve analyses were made to determine threshold values of FMR, FFMR, and FMI for wound dehiscence. The multivariate logistic regression analysis was made to assess the independent risk factors for infection site leakage. Results ROC analysis yielded threshold values of FMR 0.26, FFMR 0.73, FMI 7.46. FMI, FMR, and FFMR were associated with parameters including BMI, diabetes and wound dehiscence (80.7% sensitivity and 87.3% specificity (AUC=0.600, 95% CI: 0.789-0.919, p<0.001)). FMR> 0.26 and FFMR<0.73 were associated with high pulmonary embolism risk. Patients with FFMI (men:18.7-21 kg/m2 women 14.9-17.2 kg/m2) had significantly less postoperative atrial fibrillation and wound dehiscence. Patients with FMR>0.26 FMI>7.46 are at a 3-38 fold increased risk of wound dehiscence, irrespective of their BMI. Fat mass measurements were not associated with mortality. Conclusion Our study demonstrates that preoperative fat mass measurements can effectively predict postoperative morbidity in CABG patients. Fat mass measurements are valuable for risk prediction especially in the non-obese patients.

Publikationsverlauf

Eingereicht: 25. Mai 2025

Angenommen nach Revision: 23. Dezember 2025

Accepted Manuscript online:
26. Dezember 2025