THE USE OF EXPECTED VALUE AS AN AID TO DECISIONS REGARDING ANTICOAGULATION IN PATIENTS WITH ATRIAL-FIBRILLATION

Background. The method described provides a rational means for determi ning whether to institute chronic anticoagulation to prevent stroke in patients with chronic atrial fibrillation under a variety of clinical circumstances. Summary of Comment: The concept of expected value is u sed in conjunction with data from clinical studies to define the net v alue of anticoagulation to the patient. A full year of anticoagulation is warranted in patients with recent stroke or transient ischemic att ack thought to be due to cardiogenic embolism who feel that stroke is a very serious event with nearly as much disvalue as death. If stroke has a lesser degree of negative value to the patient, or it is uncerta in whether the stroke was in a large-vessel distribution, or it is unc ertain whether a large-vessel distribution stroke was due to cardiogen ic embolism, 6 months or less of anticoagulation may be warranted. Ind efinite anticoagulation is justifiable in most patients with chronic a trial fibrillation without a history of stroke or transient ischemic a ttack but may be contraindicated in certain patients at extremely low risk for embolism and in patients who place a low value on stroke rela tive to death and who have a modest increase in risk for fatal hemorrh age. Conclusions: The method described provides a means readily usable by clinicians to make anticoagulation decisions in patients with chro nic atrial fibrillation that will address risk-benefit tradeoffs with somewhat greater precision than current approaches.