Incidence of hematoma complication with heparin venous thrombosis prophylaxis after TRAM flap breast reconstruction.

BACKGROUND: Randomized controlled studies provide ample evidence that heparin is effective in reducing the risk of thromboembolic complications. Nevertheless, plastic surgeons are often reluctant to use heparin chemoprophylaxis for fear of postoperative bleeding. The authors investigated whether heparin chemoprophylaxis was associated with postoperative hematoma that required evacuation in patients who underwent transverse rectus abdominis myocutaneous (TRAM) flap breast reconstruction.
METHODS: A multicenter retrospective review of consecutive TRAM flap cases identified 679 patients, 392 in the heparin-treated group and 287 in the control group. The post hoc sample sizes were adequate to detect a 5 percent difference in hematoma rate with 89 percent power at an alpha level of 5 percent (p < 0.05). Outcome measures of reoperative hematoma, deep vein thrombosis, and pulmonary embolism were recorded.
RESULTS: Reoperative hematoma occurred in 0.5 percent of patients in the heparin-treated group and 1.0 percent of patients in the control group; this difference was not statistically significant (p = 0.66). Thromboembolic events were detected at a low rate (0.8 percent in the heparin-treated group versus 1.4 percent in the untreated group; p = 0.46).
CONCLUSIONS: The use of heparin for venous thrombotic prophylaxis did not increase the risk of reoperative hematoma after breast reconstruction with abdominal tissue. The authors propose a risk assessment that balances a statistical hematoma rate of 0.5 to 5 percent (clinically observed rate, 0.5 percent) with use of heparin prophylaxis against a rare (clinically observed rate, 1.4 percent) but morbid occurrence of thromboembolic complications when chemoprophylaxis is omitted.