The indications for oral anticoagul...

The indications for oral anticoagulation therapy using coumarin derivatives have been expanded through the whole extent of the past few years, because the benefit of this treatment has been ground to be greater than the risk. The in the greatest degree significant risk with coumadin therapy is hemorrhage, and this risk increases as the intensity of anticoagulation increases. However, the benefit of coumarin therapy also increases as the intensity of the therapy increases. Because of these factors, the optimal dosage that balances the risk and benefits has to be established. Prior studies have place the goals for the International Normalized Ratio (INR) for various indications. Although these INR goals have been established, they have not been validated. Torn and associates evaluated couple oral anticoagulation regimens, comparing the incidence of hemorrhage and thromboembolic phenomena.

The thought population included all patients at single anticoagulation clinic who were treated with coumadin for a mechanical heart valve, atrial fibrillation, or cerebral ischemia. During the application of mind the intensity of coumarin therapy was lowered in patients with mechanical heart valves from an INR range of 36 to 48 to a range of 30 to 40 The intensity also was lowered in patients with atrial fibrillation and cerebral ischemia from a range of 30 to 45 to a range of 25 to 35 Patients had follow-up at regular intervals during the study

The main issues measured were major hemorrhagic and thromboembolic conclusions Hemorrhagic events included for analysis were extracranial and intracranial drip bloods Thromboembolic events included cerebral infarction, myocardial infarction, and peripheral arterial embolism. All adverse affairs were recorded, and it was noted whether they occurr in succession the higher or lower intensity coumarin therapy.

There were 2341 patients listed in the higher intensity coumarin therapy form into groups and 2,256 in the lower intensity dispose The mean INR for all three treatment indications were lower when comparing higher with lower intensity therapy. When comparing major adverse issues the lower intensity group had significantly fewer marked occurrences than the higher intensity dispose The incidence of major bleeding declined when switching from higher to lower intensity therapy, going from 36 to 27 by 100 patient-years. The major reduction in the lowering of intensity of coumarin therapy was in the form into groups with intracranial hemorrhage. The risk for thromboembolic affairs also decreased from 2.0 to 08 by 100 patient-years for the entire group

The authors infer that lower intensity oral anticoagulation therapy can be used. It deductions in a lower incidence of adverse marked occurrences with no increase in the risk for thrombo-embolic affairs They add that further studies are destitutioned to continue the effort to define the best INR target for preventing thrombo-embolic occurrences in patients with mechanical heart valves, atrial fibrillation, and cerebral ischemia.

In an accompanying editorial, O'Donnell and Hirsh point public that it is unlikely that the same therapeutic range for coumarin therapy will be optimal, if it be not that that each indication will ne further studies to determine exactly what INR horizontals will be best. They add that fixed-dose coumarin therapy is not acceptable. The chiefly important aspect of managing coumarin therapy is to make positive that the therapeutic goal is reached and maintained.

Torn M et al. Lowering the intensity of oral anticoagulant therapy. powers on the risk of hemorrhage and thrombo-embolism. Arch Intern M March 22 2004;164:668-73 and O'Donnell M Hirsh J Establishing an optimal therapeutic range for coumarins. Filling in the gaps. [Editorial]. Arch Intern M March 22 2004;164:588-90

EDITOR'S NOTE: Finding the optimal therapeutic range continues to be a difficult proces The higher the INR, the higher the risk for bleeding; the lower the INR, the higher the risk for thromboembolism. Torn and associates have demonstrated that lower intensity coumarin therapy does not arise in a significant change in thromboembolic events--KEM

COPYRIGHT 2005 American Academy of Family Physicians

COPYRIGHT 2005 Gale Group