Warfarin and Aspirin drugs in SR and HF

The researchers at the Columbia University Medical center at New York have designed a clinical trial to investigate on the effect of Warfarin and Aspirin on the patients with Sinus rhythm and heart failure. The patients had decreased left ventricular ejection fraction. The Aspirin dose used in this study was 325 mg per day and the target INR or international normalized ratio of warfarin dosage used was between 2.0 to 3.5. The clinical study was conducted among 2305 patients for a period of six years. The primary outcome in this clinical study the endpoint was taken as first event among the composite end points of death or ischemic stroke or intra cerebral hemorrhage. 

The results of this clinical study revealed that warfarin group showed 7.47 events in 100 patient years while in aspirin group 7.93 events were observed in 100 patient years. The hazard ratio of 0.93 was evaluated between aspirin and warfarin groups. No significant risk of the ischemic stroke was observed in both the groups. But, the study conducted at varied timings revealed that the hazard ratio was changing in different time periods. There was decrease in the rate of Ischemic stroke in the warfarin group significantly compared with that of the aspirin group in the follow-up period. The results were observed as 0.72 events among 100 patient years against 1.36 events among 100 patient years. The hazard ratio was also decreased to 0.52. The rate of hemorrhage was evaluated as 1.78 events for 100 patient years in the warfarin group compared to that of 0.87 events in the aspirin group.  The rates of other endpoints like intra cerebral and intracranial hemorrhage were almost same in both the groups calculated as 0.27 events and 0.22 events per 100 patient years in warfarin and aspirin groups respectively.

There was no significant difference in the decrease of the primary outcome among Sinus Rhythm patients with reduced left ventricular ejection fraction between the warfarin and aspirin treatment groups. The risk of Ischemic stroke was decreased in warfarin group while the risk of major hemorrhage was seen increasing in the same group. Hence, the two groups have to be individualized to observe the responses of the mentioned endpoints.