Missed opportunities for prevention of venous thromboembolism: an evaluation of the use of thromboprophylaxis guidelines.

OBJECTIVES: To identify and characterize cases of potentially preventable venous thromboembolism (VTE): cases for which thromboprophylaxis was indicated, according to the American College of Chest Physicians (ACCP) consensus guidelines for VTE prevention, yet was administered inadequately.
DESIGN: A historical cohort study to examine all cases of deep vein thrombosis and pulmonary embolism from 1996 to 1997 at a large teaching hospital. Of these, we determined the proportion that was potentially preventable. We examined the reasons for inadequacy of prophylaxis and the setting in which preventable VTE occurred.
RESULTS: Of 253 objectively diagnosed cases of VTE in 245 patients, 44 cases (17.4%) were considered potentially preventable. This represented two thirds of all VTE cases for which thromboprophylaxis had been indicated (n = 65). Of preventable cases, the most frequent reason for inadequacy of prophylaxis was omission of prophylaxis (47.7%), followed by inadequate duration of prophylaxis (22.7%), and by incorrect type of prophylaxis (20.5%). Surgical and medical indications for thromboprophylaxis that were common among preventable cases included nonorthopedic surgery, admission to hospital for pneumonia, and stroke with lower limb paralysis. Underlying risk factors for VTE that were common among preventable cases included recent immobility, active cancer, and obesity.
CONCLUSIONS: One of six cases of all VTE and two of three cases of VTE for which thromboprophylaxis had been indicated could potentially have been prevented had physicians followed the recommended ACCP guidelines. Inadequacy of prophylaxis was most often caused by omission of prophylaxis. Missed opportunities for prevention occurred most commonly in the settings of nonorthopedic surgery, pneumonia, and stroke.