Thousands of patients who develop heart failure are routinely treated with the blood thinner, warfarin. This drug, while effective, also needs to be monitored and has a tendency to cause bleeding, which often results in hospitalization. (1)
It has been well known for many years that patients with congestive heart failure are at an increased risk for stroke and death. The chief cause of these complications are blood clots, which frequently migrate to the brain.
Warfarin and aspirin are frequently prescribed to these patients with heart failure. However, until a large randomized study, the WARCEF trial, was performed, no one had ever compared aspirin to warfarin in patients with heart failure.
Now the WARCEF trial shows that patients with heart failure, whose heart rate is regular, do not benefit from warfarin. The patients selected also had reduced ability for their hearts to pump out blood from the left side, called reduced left ventricular ejection fraction (LVEF).
In the WARCEF study, 2305 patients from several countries were either administered aspirin or warfarin, and followed for an average of three and a half years. (2)
The results of the study were presented by Shunichi Homma, MD, Margaret Milliken Hatch professor of medicine at Columbia University in New York City, at the International Stroke Conference in Feb 2012.
The end result was that warfarin was no better than aspirin in most patients with heart failure and reduced LVEF. Although warfarin did slightly decrease the risk of stroke, it was also associated with a much higher bleeding rate.
The conclusions of this large study now provide physicians with some direction as to which patients’ needs warfarin or aspirin
However, it should be noted that there are some patients with heart failure who many benefit from warfarin. These patients include those who also have abnormal heart rhythm (atrial fibrillation), history of thromboembolism or formation of blood clots in the left ventricle.
Based on the WARCEF study, future evaluation of use of blood thinners in patients with heart failure will focus on the underlying problems. If atrial fibrillation or a history of blood clots is not present, aspirin should be considered. "The choice between warfarin and aspirin should be individualized."
1. Chimowitz MI et al. Comparison of warfarin and aspirin for symptomatic intracranial arterial stenosis. N Engl J Med. 2005 Mar 31;352(13):1305-16.
2. Homma S et al. Warfarin and Aspirin in Patients with Heart Failure and Sinus Rhythm. N Engl J Med. 2012 May 2. [Epub ahead of print]
Reviewed May 7, 2012
by Michele Blacksberg RN
Edited by Jody Smith