The effect of extended post-discharge chemical thromboprophylaxis on venous thromboembolism rates after bariatric surgery: a prospective comparison trial.

BACKGROUND: The effect of extended post-discharge thromboprophylaxis (ETP) on venous thromboembolism (VTE) rates following bariatric surgery (BS) is unknown.

METHODS: 308 consecutive patients who underwent BS between 2003 and 2007 and who had > 1 month of follow-up were included. In-hospital-only VTE prophylaxis (group A), or extended 10-day ETP (group B) was used in 132 and 176 patients, respectively. All patients underwent bilateral lower extremity venous Doppler studies (BLEVDS) prior to discharge. Primary endpoint was the incidence of VTE within 30 days postoperatively. VTE was defined as a clinically evident deep vein thrombosis or pulmonary embolism documented by positive BLEVDS, or computed chest tomography. The primary safety endpoint was bleeding associated with > or = 2 g/dL decrease in hemoglobin compared with baseline, transfusion or reoperation.

RESULTS: The incidence of VTE was 1.9% (6/308); 66.6% (4/6) of cases occurred after cessation of thromboprophylaxis. There were no deaths in either group. With the exception of percentage open surgical approach (A: 3% versus B: 0%, p = 0.03), percentage conversions (A: 0 versus B: 3.8%, p = 0.01), and hospital stay (A: 3 versus B: 2.2 days, p < 0.0001), the two groups were comparable in relation to age, sex, body mass index, percentage revision surgery, operative time, and history of VTE. VTE rate was significantly higher in group A (A: 4.5% versus B: 0%, p = 0.006). Although morbidity was higher in group A (A: 12.1% versus B: 1.1%, p < 0.0001), no VTE event occurred in patients who had other complications. The incidence of significant bleeding was lower in group B (A: 5.3% versus B: 0.56%, p = 0.02).

CONCLUSIONS: ETP is safe and effective in reducing the incidence of VTE as compared with in-hospital thromboprophylaxis only.