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BACKGROUND: Venous thromboembolic events (VTE) are a significant cause of postoperative morbidity and a focus of patient safety initiatives. The Caprini Risk assessment model has been validated for plastic surgery patients. Despite giving appropriate prophylaxis, based on this model, we observed a high incidence of VTE in patients undergoing microsurgical breast reconstruction. To explore factors contributing to this incidence and to improve postoperative outcomes, we compared underserved patients undergoing microsurgical breast reconstruction who sustained postoperative VTEs to those who did not.
METHODS: A retrospective review of all patients that underwent microsurgical free flap breast reconstruction at Montefiore Medical center from January 2009-January 2015 was conducted. All patients had preoperative subcutaneous heparin administered prior to induction of anesthesia and postoperative chemoprophylaxis per Caprini risk assessment model. Patients were divided into two cohorts; those sustaining postoperative VTE and those who did not. Patients were compared based on demographics, comorbidities, operative time, preoperative heparin administration, estimated intraoperative blood loss, need for transfusion, volume of transfusion, and discharge on postoperative aspirin. RESULTS: A total of 133 patients underwent microsurgical breast reconstruction during the study period. Nine patients (7.3%) had postoperative VTE and there was one (0.8%) death. The average postoperative day for patient presentation was 14.7 days (range: 0-44 days). When comparing patients who had VTE to control patients, there was no difference in age, BMI, type of flap, radiation/chemotherapy status, length of stay, or average OR time. Several factors were associated with the development of VTE: Race, average transfusion volume, and lack of discharge on aspirin. Patients having VTE were more likely to be Hispanic (33.3% (n=3) versus 8.0% (n=33)(p=0.011)), have an increased mean transfusion volume (455.5±367.8 mL versus 139.51± 221.7 (p=0.03)), and being discharged without aspirin (77.8%(n=7) and 58.1% (n=72) (p=0.003)). Absolute need for transfusion trended towards significance (66% (n=6) versus 32.3% (n=40) (p=0.064)) and while estimated blood loss was not significantly different between the cohorts is likely secondary to inaccuracy of estimation of intraoperative blood loss.
CONCLUSIONS: Patients sustaining postoperative venous thromboembolic events after microsurgical breast reconstruction are more likely to have increased volume of blood transfusions and lack of discharge on postoperative aspirin. Benefits of preoperative subcutaneous heparin, may be negated by the increased risk for bleeding and secondary activation of coagulation cascade.