The Effect of Blood Pressure on Hematoma Formation with Perioperative Lovenox in Excisional Body Contouring Surgery

Jordan P. Farkas, M.D., Jeffrey M. Kenkel, M.D., Daniel A. Hatef, M.D., Gabrielle Davis, B.S., Tuan Truong, B.S., Rod J. Rohrich, M.D, Spencer A. Brown, PhD

Dallas, Texas

INTRODUCTION: The use of low molecular weight heparin (LMWH) is considered by some to be the standard in thrombo-embolic prevention in massive weight loss and excisional body contouring patients.(1) The risk of pulmonary embolus may be small (0.1%- 0.3%) but can potentially be fatal .(2) The prevention of venous thrombo-embolism has become a very popular topic across all surgical specialties. Studies have demonstrated LMWH’s ability to decrease the risk of thrombo-embolism, but with the potential to increase bleeding intra- and post operatively. This may lead to significant hematoma formation or post operative blood transfusion.(3-6)

In abdominoplasty patients, hematoma development has been reported in the literature between anywhere from 1-10%.(1,7-12) Hematoma formation in surgical wounds has a negative effect on wound healing, recovery time, hospital stay, and overall morbidity. With the sizeable increase of massive weight loss patients and excisional body contouring surgery, thrombo-embolism has become a popular topic amongst plastic surgeons. The optimal timing, dosage, and duration of LMWH in this patient population has yet to be determined and is currently being explored.

With the increased awareness and prophylaxis against post operative thrombo-embolism at our institution, we underwent a retrospective chart review of peri-operative blood pressures and their relationship to hematomas in patients undergoing body contouring being treated with enoxaparin.

METHODS: Three hundred and sixty consecutive excisional body contouring patients’ charts from two senior surgeons (JMK, RJR) at our institution were reviewed. We then further compared separate groups of patients: ten of which experienced a hematoma after excisional body contouring surgery with perioperative Lovenox; and ten similar patients with respect to sex, surgery type, massive weight loss status, and Lovenox administration, who did not have a hematoma. Pre- and post-operative blood pressures were recorded, as were blood pressures during the last two hours of surgery. Mean arterial pressures were calculated for all time points, and mean intraoperative MAP was statistically compared to pre- and post-operative MAP, for the two groups. The mean intra-operative blood pressures were an average of the blood pressures taken over the last two hours of the case at which time hemostasis and closure were being obtained.

RESULTS: The mean pre-operative MAP for each group was the same (97.5 mmHg vs. 95.8 mmHg; p = 0.61). The mean MAP for the last two hours of each case was significantly lower in the hematoma group (66.7 mmHg vs. 82.4 mmHg; p < 0.0001), and a higher mean post-operative MAP reached significance in the hematoma group (96.3 mmHg vs. 88.5 mmHg; p = 0.05). Both the difference between intra- and pre-op blood pressure (30.7 mmHg vs. 13.4 mmHg; p < 0.0001), and between intra- and post-op blood pressure (29.6 mmHg vs. 7.0 mmHg; p < 0.0001) were increased in the hematoma group versus the non-hematoma group.

Hematoma Rate with Lovenox Use

Hematoma (yes) / Hematoma (no) / Total
Lovenox / 10 (7.3%) / 127 (92.7%) / 137 (38.3%)
No- Lovenox / 1 (0.5%) / 220 (99.6%) / 221 (61.7%)
Total / 11 (3.1%) / 347 (96.9%) / 358*

Fisher’s Exact Test indicates a significantly higher (p<0.001) occurrence of Hematoma among those subjects receiving Lovenox .

* two charts were excluded from the review

Mean Intra-Operative Mean Arterial Pressure

N / Mean / Standard Deviation / p-value
Patients with Hematoma / 10 / 66.7 / 6.85 / < 0.0001
Complication-Free Patients / 10 / 82.4 / 5.24

t-Test comparison of means indicates significantly lower intraoperative MAP for patients who had hematoma

CONCLUSION: Many patients undergoing excisional body contouring surgery are at high risk for VTE and may need perioperative chemoprophylaxis. Our data supports that the anaesthesia induced hypotension may in fact be helpful for intra-operative hemostasis but may lead to the development of postoperative hematomas through blood pressure swings in patients undergoing body contouring with chemoprophylaxis. Maintaining a normotensive intraoperative blood pressure and vigilance in recognizing and treating post-operative hypertension, may reduce the hematoma rate seen with perioperative LMWH administration.

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