Validation of the Caprini risk assessment model in plastic and reconstructive surgery patients

Abstract

Background: The Venous Thromboembolism Prevention Study (VTEPS) Network is a consortium of 5 tertiary referral centers established to examine venous thromboembolism (VTE) in plastic surgery patients. We report our midterm analyses of the study's control group to evaluate the incidence of VTE in patients who receive no chemoprophylaxis, and validate the Caprini Risk Assessment Model (RAM) in plastic surgery patients.

Study design: Medical record review was performed at VTEPS centers for all eligible plastic surgery patients between March 2006 and June 2009. Inclusion criteria were Caprini score ≥3, surgery under general anesthesia, and postoperative hospital admission. Patients who received chemoprophylaxis were excluded. Dependent variables included symptomatic deep vein thrombosis (DVT) or pulmonary embolism (PE) within the first 60 postoperative days and time to DVT or PE.

Results: We identified 1,126 historic control patients. The overall VTE incidence was 1.69%. Approximately 1 in 9 (11.3%) patients with Caprini score >8 had a VTE event. Patients with Caprini score >8 were significantly more likely to develop VTE when compared with patients with Caprini score of 3 to 4 (odds ratio [OR] 20.9, p < 0.001), 5 to 6 (OR 9.9, p < 0.001), or 7 to 8 (OR 4.6, p = 0.015). Among patients with Caprini score 7 to 8 or Caprini score >8, VTE risk was not limited to the immediate postoperative period (postoperative days 1-14). In these high-risk patients, more than 50% of VTE events were diagnosed in the late (days 15-60) postoperative period.

Conclusions: The Caprini RAM effectively risk-stratifies plastic and reconstructive surgery patients for VTE risk. Among patients with Caprini score >8, 11.3% have a postoperative VTE when chemoprophylaxis is not provided. In higher risk patients, there was no evidence that VTE risk is limited to the immediate postoperative period.

Figure 1

The Caprini Risk Assessment Model. (Adapted from: Caprini JA. Thrombosis risk assessment as a guide to quality patient care. Dis Mon 2005;51:70–78 with permission.)

Figure 2

Histogram of Caprini score in plastic and reconstructive surgery patients (n=1,126).

Figure 3

Rates of VTE in the first 60 post-operative days by stratified Caprini score (n=1,126).

Figure 4

Survival analysis examining time to VTE by stratified Caprini score (n=1,087).