The benefit of anticoagulation for prevention of stroke in patients with atrial fibrillation has been well established. However, the benefit is always to be weighed against the risk, in this case, primarily bleeding. Among the many potential reasons not to anticoagulate, other factors that predispose to bleeding are often brought up. My question is about one such condition — thrombocytopenia (low platelets).
In a patient with atrial fibrillation who otherwise meets criteria for anticoagulation,1 what level of thrombocytopenia2 is considered a relative contraindication to anticoagulation?
1. Of course, not all "meets criteria" are the same. For the sake of the question, let't discuss the sort of "middle risk" group (nonvalvular afib, CHA2DS2-VASc = 2-3). Let us also assume no prior bleeding history.
2. Using whatever units you would like, but as far as I know normal people talk about count per mm3 = mL, with a normal range 150k-400k.