Wednesday, September 29, 2010

combination of Aspirin,Plavix & Warfarin - how bad or how good?

I am sure you had come across those patients who had been on aspirin & warfarin ..or...plavix & warfarin...or rarely all three (either intentionally or by mistake!!). Well...a patient with CAD might benefit more from a antiplatelet...but may need warfarin for A.fib ....will he benefit from both? A recent article from Arch of Int Medicine tried to address these issues by calculating the risk of bleeding associated with each combination.
Lets look at the risk of stoke with A fib at 1 the numbers from the above study would make more sense.

Risk of stroke with A fib - commonly assessed with CHADS2 score
CHADS score of 0,1,2,3,4,5 & 6 carries a 1 year stroke risk of ..roughly 2%,3%, 4%, 6%, 8%, 12% & 18% respectively.So we usually start treatment to prevent this thromboembolic risk by starting them on either antiplatelets or warfarin. This question about warfarin or no warfarin always pops up when we see a patient with A fib.

Now lets see the numbers from the above study where they looked at a cohort of 82,000 patients discharged with a diagnosis of Atrial fibrillation. During a follow up period of 3 years ..11%(13,000 pts) had a fatal or non-fatal bleeding.Having warfarin as the standard ..the hazard ratio for the above end point is as follows
For Aspirin alone - 0.93
for plavix alone - 1.06
for aspirin + plavix - 1.66
for aspirin + warfarin - 1.83
for plavix + warfarin - 3.08
for aspirin +plavix+warfarin - 3.70

Clearly this was something that was expected ..based on previous studies. The crude incidence rate of bleeding was 13% for plavix +warfarin, and 15% for triple therapy. So having these numbers a better idea for making a risk-benefit decision !! ...So ..whoever your pt is....aspirin+plavix+warfarin seems to be a bad combination!