Hemodynamic alterations in the transferred tissue to lower extremities.

A higher incidence of failure has been reported for free flaps transplanted to the lower extremities. However, the physiological background of this phenomenon has not been elucidated. We reviewed the 3-day postoperative hemodynamic data for 103 free flaps, including the in situ venous pressure (N = 103), arterial pressure (N = 53), and surface blood flow (N = 42). The cases were divided into two groups based on the recipient site, i.e., lower extremity (the LE group: N = 29) and the other (non-LE group: N = 74). The venous pressure was significantly higher in the LE group (26.6 +/- 2.2 vs. 14.8 +/- 1.2 mmHg), whereas the arterial pressure immediately after surgery was lower than the non-LE group. The hemodynamic data within the transferred tissues demonstrated significant differences between groups, especially in the early postoperative period. There is a possibility that the high venous pressure may aggravate the poor perfusion in tissues transferred to the lower extremities.