Incidence of venous thromboembolism after cardiovascular surgery.

Background: Among venous thromboembolism, pulmonary thromboembolism (PTE) is one of the most serious postoperative complications. Deep venous thrombosis (DVT) is the main cause. Considering the unknown prevalence of DVT and PTE in the postoperative period of cardiovascular surgery in Japan, we investigated the incidence in consecutive patients who underwent cardiovascular surgery.

Methods: A total of 225 patients who underwent cardiovascular surgery at four hospitals consented to participate in the study. We assessed DVT using lower extremity venous ultrasound preoperatively and postoperatively. Seven patients with preexisting DVT were excluded. Postoperative antithrombotic therapy was administered at the discretion of the attending physician at each institution. The postoperative intermittent pneumatic compression therapy followed the standard prophylaxis protocol at each institution. Patients were grouped into DVT and non-DVT cohorts for comparison. Continuous variables were expressed as means ± standard deviations and compared by the t-test.

Results: The analysis of lower extremity venous ultrasound images indicated that DVT developed in 16 of the 218 study patients (DVT, 7.3%). No patient had PTE. Procedure-related data revealed significantly higher total blood transfusion (DVT group: 61.2 ± 49.9 IU vs. non-DVT group: 27.7 ± 30.2 IU:  = 0.018, effect size = 1.048) in the DVT group. The multivariate logistic regression predictor of DVT based on preoperative, intraoperative, and postoperative factors was blood transfusion ( = 0.005, 95% confidence interval 1.010-1.059, odds ratio 1.034).

Conclusions: The incidence of postoperatively developed DVT was 7.3% in this study.