Evaluating risks versus benefits of warfarin therapy

Cardiology Review® Online, Decmber 2005, Volume 22, Issue 12

An 82-year-old man presented for a routine medical evaluation. On examination, his heart rate was 82 beats per minute and irregular; an electrocardiogram showed that he had atrial fibrillation. He had a history of paroxysmal atrial fibrillation, but he had declined warfarin (Coumadin) therapy in the past. Recently, however, he had become increasingly concerned about the possibility of ischemic stroke associated with atrial fibrillation and wanted to discuss the risks and benefits of warfarin.

In addition to atrial fibrillation, the patient had a history of hypertension. He was taking a beta blocking agent and an aspirin daily and had no previous history of stroke or hemorrhagic events. He lived alone and was able to function independently, but had noted some decline in functional status in the past few years. His physician described the benefits of stroke risk reduction with warfarin therapy. Given the patient’s older age, however, the physician was concerned about the risk of warfarin-associated intracranial hemorrhage. Although the physician knew that lower international normalized ratio (INR) intensities are not as effective as INRs of 2.0 to 3.0 for the prevention of ischemic stroke, he felt that perhaps a lower intensity would be safer for the patient in terms of reducing his risk of intracranial hemorrhage.

The patient discussed the risks and benefits of warfarin therapy with his physician. Because of his older age and history of hypertension, his physician believed that his annual risk of ischemic stroke without warfarin was greater than his risk of intracranial hemorrhage while receiving warfarin; therefore, the patient opted to start warfarin therapy. His physician recommended a target INR of 2.5, with a range of 2.0 to 3.0.