Study Objective: To determine the efficacy and safety of adjusted subcutaneous calcium heparin compared with continuous intravenous calcium heparin as the initial treatment for acute deep vein thrombosis.
Design: Randomized control trial.
Setting: University-affiliated general hospital.
Patients: Of 111 consecutive patients considered, 103 had acute proximal or calf vein thrombosis confirmed by ascending venography and met all other eligibility criteria.
Interventions: Patients were randomly assigned to receive subcutaneous or intravenous heparin. The subcutaneous regimen consisted of an initial dose of 15 000 U, adjusted thereafter to prolong the activated partial thromboplastin time to 50 to 70 seconds. The continuous intravenous regimen was begun as a bolus injection of 5000 U, followed by an infusion of 1250 U/h, adjusted to maintain the activated partial thromboplastin time at 50 to 70 seconds.
Measurements and Main Results: There was no significant difference in the rate of new pulmonary embolism between the two groups, as defined by new high-probability defect on repeat ventilation-perfusion scintigrams of the lung in 96 (93%) of the patients after 7 to 10 days of treatment. Five of forty-seven patients in the subcutaneous group and 5 of 49 in the intravenous group developed pulmonary embolism (95% confidence interval [CI] for the difference, -13.1% to 12.2%). Similarly, there was no significant difference in the frequency of hemorrhagic complications. Five of fifty-one patients in the subcutaneous group and 5 of 52 in the intravenous group had hemorrhagic complications (95% CI for the difference, -11.2% to 11.6%).
Conclusion: Adjusted subcutaneous calcium heparin may be an effective and safe alternative to continuous intravenous calcium heparin in the initial treatment of acute proximal deep vein thrombosis.