Beyond BMI: Subcutaneous adipose tissue and smoking history as Predictors of Postoperative Complications in DIEP-flap Breast Reconstruction.

[BACKGROUND] Autologous breast reconstruction improves quality of life after mastectomy but carries a significant risk of postoperative complications. Body Mass Index is commonly used for risk stratification, despite limitations in reflecting body composition and fitness. This prospective study aimed to identify more optimal predictors for complication risk, including cardiopulmonary condition, smoking history, and body fat composition.

[METHODS] In this prospective study, patients undergoing DIEP-flap reconstruction were assessed preoperatively with cardiopulmonary exercise testing and abdominal CT angiography. Subcutaneous adipose tissue, visceral adipose tissue, and intramuscular adipose tissue were measured from CT images. Complications were classified using the Clavien-Dindo system. Predictors of postoperative complications were identified using logistic regression and validated in an independent cohort.

[RESULTS] Postoperative complications occurred in 46% of the 39 enrolled patients, with 33% requiring medical intervention (CD grade ≥ II). Physical fitness, measured using CPET, was not associated with CD≥ II complications. In multivariable analysis, only SAT and smoking history were independent predictors of complications, explaining 56% of the variance. A SAT threshold of 451 cm² for non-smokers and 204 cm² for patients with smoking history was identified, achieving 100% sensitivity and 77% specificity. Validation in an independent cohort confirmed the predictive value of SAT (AUC 0.715).

[CONCLUSION] Physical fitness and BMI were not independent predictors of postoperative complications. SAT and smoking history were stronger predictors and can be easily accessed through routine CT imaging. These findings support the use of SAT as a practical, more accurate risk stratification tool for autologous breast reconstruction candidates.