Working Toward Defining Frailty in Breast Surgery: A Multi-institution Cohort Study Identifying Risk Factors of Free Flap Failure Following Autologous Breast Reconstruction.

[BACKGROUND] The integration of frailty assessments into preoperative evaluation protocols is essential for enhancing surgical procedure safety. As autologous breast reconstruction (ABR) increases in popularity, it is critical to stratify risk in patients with significant comorbidities with an ABR-specific frailty model. The aim of this study was to identify comorbidities associated with patients for unilateral or bilateral ABR flap failure, to develop a frailty index with a multi-institutional database.

[METHODS] The TriNetX database was queried for patients who underwent free flap breast reconstruction (CPT code 19364) between 2016 and 2024 across 89 healthcare institutions. Patients who experienced unilateral or bilateral flap failure (ICD-10 T86.821) were identified; preoperative comorbidities that occurred at a significantly different frequency were detected. Subsequently, univariate and multivariable logistic regression analyses were used to identify independent risk factors of free flap failure. Odds ratios were converted into relative risk ratios and probabilities using the baseline frequency of flap failure without any comorbidity.

[RESULTS] A total of 10,291 patients who underwent either unilateral or bilateral primary free flap ABR were identified. A total of 120 (1.17%) patients experienced partial or total flap failure. Comorbidities of interest were seen among infectious, oncologic, hematologic, cardiovascular, gastrointestinal, and dermatologic systems. Significant risk factors on multivariable logistic regression included history of anemia (OR, 2.87), breast abscess (OR, 2.98), chronic obstructive pulmonary disease (OR, 3.08), hypertension (OR, 1.69), and body mass index ≥30 (OR, 2.37) (P < 0.05 for all). The baseline frequency of flap failure without any comorbidity was 0.73%. The presence of one or more risk factors increased the probability of 1-week flap failure anywhere from 1.23% (hypertension alone) to 43.69% (all five comorbidities).

[CONCLUSIONS] Select preoperative comorbidities were identified as patient-specific risk factors for postoperative flap failure. A future direction may also include identifying complications specific to certain flap techniques and within partial and total flap failures, as well as prospectively tracking data per flap, rather than per patient through the TriNetX database.