Previously aspirin and clopidogrel were found to having an increase risk of mortality in patients on haemodialysis. However warfarin is known to have a survival advantage in patients with
atrial fibrillation as the drug prevents clot formation in the poorly contracting left atrium of the heart. Any reduction in clot formation results in a reduction in the chance of a clot passsing from the heart into the brain resulting in an ischemic stroke. The present
study looked at warfarin use in an area where it has been established to be beneficial in other patient groups. However in this study of 1671 haemodialysis patients with atrial fibrillation warfarin was found to increase the risk of stroke in a dose dependent manner. In other words the risk of a stroke was highest in patients on the highest dose of warfarin. The study incidentally did not demonstrate an increased risk of stroke due to ASA and clopidogrel this time around. However
aspirin and clopidogrel are not as effective as warfarin in the normal population for the prevention of stroke and have a mixed track record in the prevention of even access related clotting. The study did note that patients who had blood tests done regularly at the centre where they are dialysed to monitor the effectiveness of warfarin and appropirately adjust the dosage of the drug had the lower risk for stroke compared to the unattended use of warfarin.
This finding is to be expected as many drugs and substances interact with warfarin making it very difficult to maintain a smooth level of the drug within the body.
I suspect that warfarin use in a highly monitored setting may have some use in patients with atrial fibrillation and further studies designed to tease out this relationship will likely show that benefit.
No comments:
Post a Comment