Summary

The purpose of this study was to evaluate whether the determinationof pretest probability using a simple clinical model and the SimpliREDD-dimer could be used to improve the management of hospitalized patientswith suspected deep-vein thrombosis. Consecutive hospitalizedpatients with suspected deep-vein thrombosis, had their pretest probabilitydetermined using a clinical model and had a SimpliRED D-dimerassay. Patients at low pretest probability underwent a single ultrasoundtest. A negative ultrasound excluded the diagnosis of deepveinthrombosis whereas a positive ultrasound was confirmed by venography.Patients at moderate pretest probability with a positive ultrasoundwere treated for deep-vein thrombosis whereas patients with an initialnegative ultrasound underwent a single follow-up ultrasound one weeklater. Patients at high pretest probability with a positive ultrasound weretreated whereas those with negative ultrasound underwent venography.All patients were followed for three months for the development of venousthromboembolic complications. Overall, 28% (42/150), and 10%(5/50), 21% (14/71) and 76% (22/29) of the low, moderate and highpretest probability patients, respectively, had deep vein thrombosis.Two of 111 (1.8%; 95% CI = 0.02% to 6.4%) patients considered tohave deep vein thrombosis excluded had events during three-month follow-up. Overall 13 of 150 (8.7%) required venography and serial testingwas limited to 58 of 150 (38.7%) patients. The negative predictivevalue of the SimpliRED D-dimer in patients with low pretest probabilitywas 96.2%, which is not statistically different from the negative predictivevalue of a negative ultrasound result in low pretest probabilitypatients (97.8%). Management of hospitalized patients with suspecteddeep-vein thrombosis based on clinical probability and ultrasound ofthe proximal deep veins is safe and feasible.