Vasopressor Use in Free Flap Reconstruction: A Multicenter Propensity-Matched Analysis of Outcomes.

BACKGROUND: The use of intraoperative vasopressors during microvascular free flap reconstruction remains controversial due to concerns regarding vasoconstriction and impaired flap perfusion. This study evaluates the association between vasopressor use and postoperative outcomes across a large, multicenter cohort. METHODS: A retrospective cohort study was performed using the TriNetX Collaborative Network. Adult patients undergoing free flap reconstruction were identified and stratified by intraoperative vasopressor exposure. Propensity score matching (1:1) was used to balance baseline characteristics. Outcomes within 90 days included flap-related complications, wound complications, reoperation, and mortality. Subgroup analyses were conducted by flap type and vasopressor agent. RESULTS: A total of 43,157 patients were identified, with 17,970 matched pairs included. Overall vasopressor use was associated with increased risks of infection (RR 1.10, 95% CI 1.05-1.15; p < 0.01) and wound dehiscence (RR 1.09, 95% CI 1.02-1.15; p = 0.01), and decreased rates of debridement (RR 0.84, 95% CI 0.78-0.90; p < 0.01). Phenylephrine demonstrated the most consistent association with adverse wound outcomes, including infection (RR 1.17, 95% CI 1.10-1.24; p < 0.01), dehiscence (RR 1.15, 95% CI 1.06-1.24; p < 0.01), skin graft failure (RR 1.17, 95% CI 1.03-1.33; p = 0.02), and anastomotic revision (RR 1.29, 95% CI 1.02-1.65; p = 0.04). Breast reconstructions showed higher complication rates with vasopressor exposure, extremity reconstructions demonstrated minimal differences, and head and neck reconstructions showed increased infection, skin graft failure, and mortality. No consistent increase in flap failure or reoperation rates was observed. CONCLUSIONS: Intraoperative vasopressor use is associated with modest increases in select postoperative complications, with variability by agent and flap type. Phenylephrine may carry higher risk, while other agents demonstrate more neutral effects. These findings support a selective, context-dependent approach to vasopressor use during free flap reconstruction.