Original Paper

Randomized Assessment of a Warfarin Nomogram for Initial Oral Anticoagulation after Venous Thromboembolic Disease
M.J. Kovacs^b, M. Cruickshank^b, P.S. Wells^c, H. Kim^a,b, I. Chin-Yee^a,b, B. Morrow^a, E. Boyle^a, J. Kovacs<sup>a

a</sup>Department of Hematology, London Health Sciences Centre, and
^bDepartment of Medicine, University of Western Ontario, London, Ont., and
^cDepartment of Medicine, University of Ottawa, Ottawa, Ont., Canada

Address of Corresponding Author

Haemostasis 1998;28:62-69 (DOI: 10.1159/000022414)

  Key Words

• Warfarin
• Venous thromboembolism
• Treatment
• Nomogram

  Abstract

Standard treatment for venous thromboembolism is parenteral heparin followed by warfarin. In this study we assess whether a standardized method of ordering warfarin reduces the duration of hospitalization. Consecutive patients were randomized to receive warfarin managed by attending physicians or by a nomogram. Patients were stratified according to primary or secondary venous thromboembolism. Prothrombin times were measured daily and heparin was given for a minimum of 5 days and stopped when the International Normalized Ratio was >1.9. Patients were followed for 3 months. There were 111 patients, 80 with primary and 31 with secondary venous thromboembolism. Overall there were no differences between the two warfarin groups with respect to length of admission. Given the prolonged duration of admission in many patients with secondary venous thromboembolism, a subset analysis was conducted on the 80 patients with primary venous thromboembolism. Patients in the standard group stayed significantly longer than patients in the nomogram group (6.0 vs. 5.6 days, p = 0.02). The warfarin nomogram as tested is safe and leads to a significantly shorter length of stay for patients with primary venous thromboembolism as compared to standard practice.

  Author Contacts

Dr. Michael J. Kovacs, Rm. 2760, Phase 1
London Health Sciences Centre, 800 Commissioners Rd. E.
London, ON N6A 4G5 (Canada)
Tel. +1 519 685 8475, Fax +1 519 685 8477
E-Mail michael.kovacs@lhsc.on.ca

  Article Information

Received: Received: October 16, 1998
Accepted: October 28, 1998
Number of Print Pages : 8
Number of Figures : 1, Number of Tables : 4, Number of References : 15