Active thrombin is a relatively poor inducer of GPVI shedding. (A) sGPVI measured in either recalcified citrated PRP in the absence or presence of 0.2 U/mL enoxaparin that inhibits FXa and thrombin, or citrated PRP treated with 1 U/mL thrombin in the absence or presence of 1 μg/mL rivaroxaban that selectively inhibits FXa. (B) sGPVI was measured in citrated PRP, either untreated or treated with thrombin in the absence or presence of 5 U/mL hirudin or 100μM GM6001.