Asymptomatic patients at high risk for deep venous thrombosis who receive inadequate prophylaxis should be screened

Background, Patients after stroke and major orthopedic surgery have increas ed factors for developing deep vein thrombosis. We sought to determine the implications of screening highrisk patients to detect proximal deep vein th rombosis. Methods, We used decision analysis to determine the implications of screeni ng vs not screening asymptomatic high risk patients with duplex ultrasonogr aphy to detect proximal deep venous thrombosis. The outcomes were bleeding, pulmonary embolism, death, and number of patients with true-positive, fals e-positive, and false-negative tests. Results. Screening with ultrasonography, all asymptomatic patients who rece ive appropriate prophylaxis, prevalence 5%, would result in the treatment o f 3.1% patients with proximal deep vein thrombosis (true positives); 2.9% w ithout proximal deep vein thrombosis (false positives) and in the lack of d iagnosis in 1.9% patients (false negatives). At a prevalence of 20%, no pro phylaxis, screening would result in the treatment of 12.4% patients with pr oximal deep vein thrombosis (true positives), 2.4% without proximal deep ve in thrombosis (false positives), and in the lack of diagnosis in 7.6% of pa tients (false negatives). Conclusions, Screening high-risk patients who receive prophylaxis is not wa rranted. Patients who receive no prophylaxis should be screened with ultras onography.