PHYSICIAN-GUIDED TREATMENT COMPARED WITH A HEPARIN PROTOCOL FOR DEEP-VEIN THROMBOSIS

Background: Effective heparin therapy, defined by therapeutic prolonga tion of the activated partial thromboplastin time (APTT), decreases th e risk of recurrent venous thromboembolism. Achieving therapeutic prol ongation of the APTT within 24 hours of the start of heparin therapy h as proved difficult. We hypothesized that a protocol that delivered hi gh initial heparin infusions to patients without identifiable risk for bleeding complications would decrease the time to achieve a therapeut ic anticoagulant effect without increasing the incidence of major blee ding complications. Methods: To test this hypothesis, we studied concu rrent patient cohorts. We defined a therapeutic anticoagulant effect ( APTT > 55 seconds) to be an APTT more than 1.5 times the upper limit o f normal. Twenty patients with acute symptomatic deep vein thrombosis received a 5000-U heparin bolus, followed by 1680 U/h (low risk to ble ed) or 1240 U/h (high risk to bleed), adjusted by protocol-directed re sponse to APTT results. Forty-eight patients with deep vein thrombosis were treated by their physicians. The Kaplan-Meier method was used to examine the proportion of patients who achieved an APTT greater than 55 seconds as a function of time. Results: The two study cohorts did n ot differ with respect to age, weight, or risk factors for venous thro mboembolism. Analysis of Kaplan-Meier curves showed that the heparin p rotocol decreased the time to achieve a therapeutic anticoagulant effe ct (P = .025). Ten (91%) of 11 patients (95% confidence interval, 59% to 100%) without risks to bleed who were treated by the heparin protoc ol and 29 (60%) of 48 patients (95% confidence interval, 45% to 74%) n ot treated by the protocol had an initial therapeutic APTT (P = .006). Conclusion: A protocol that delivers higher initial heparin infusions to patients without identifiable risks for bleeding decreases the tim e needed to achieve therapeutic prolongation of APTT, when compared wi th nonprotocol physician management.