Nuisance and alarming bleeding do not correlate with on-treatment platelet reactivity

We hypothesized that patients with a history of either alarming or nuisance bleeding events, compared to those with no history of bleeding, would have lower levels of on-treatment platelet reactivity (aspirin and a thienopyridine).

In total, 42 patients with no bleeding, 34 with nuisance bleeding, and 14 with alarming bleeding underwent platelet reactivity testing 1 month to 1 year after PCI with light transmission aggregometry (LTA 5 and 20 μM adenosine disphosphate [ADP]), vasodilator stimulated phosphoprotein phosphorylation (VASP) and VerifyNow P2Y12. Clinical and demographic characteristics of the 3 groups were generally similar, except that patients with alarming bleeding were less likely to be Caucasian; only 6 patients (6.7%) were taking prasugrel. There was considerable overlap between no bleeding, nuisance bleeding and alarming bleeding groups with respect to on-treatment platelet reactivity. Furthermore, there was no difference in the median platelet reactivity values for all assays. Prevalence of high on-treatment platelet reactivity did not differ among the 3 groups; 32.6% of patients had high on-treatment platelet reactivity as measured by LTA with 5 μM ADP (P=.91); 40.0% as measured by VASP (P=.35); and 35.6% as measured by VerifyNow P2Y12 (P=.61).

The use of platelet reactivity assays to identify patients on thienopyridine therapy at higher risk of bleeding is an unfounded strategy.