Increased risk of minor bleeding and antiplatelet therapy cessation in patients with acute coronary syndromes and low on-aspirin platelet reactivity. A prospective cohort study

Bleeding negatively affects prognosis and adherence to antiplatelet therapy after acute coronary syndromes (ACSs). The potential association of on-aspirin platelet reactivity and bleeding is not established. We sought to determine whether low on-aspirin platelet reactivity (LAPR) is associated with bleeding events and antiplatelet therapy compliance in patients with ACSs receiving coronary stenting. On-aspirin platelet reactivity was measured by the VerifyNow™ Aspirin assay (Accumetrics Inc., San Diego, CA, USA) in 531 patients with ACS. Cut-offs for LAPR were calculated by receiver-operating characteristic curve (ROC) analysis. Bleeding was reported according to Bleeding Academic Research Consortium (BARC) definition. The endpoints were minor bleeding (BARC types 1 or 2), major bleeding (BARC types 3 or 5) and antiplatelet therapy cessation during 6-months follow-up. By ROC analysis the VerifyNow™ Aspirin assay was able to distinguish between patients with and without minor bleeding (area under the curve [AUC] 0.66, 95 % confidence interval [CI] 0.62–0.70, P < 0.0001) whereas major bleeding could not be predicted by the assay (AUC 0.54, 95 % CI 0.49–0.58, P = 0.473). By logistic regression, LAPR was associated with increased risk of minor bleeding (odds ratio [OR] 4.32, 95 % CI 2.78–6.71, P < 0.0001) but not major bleeding (OR 2.05, 95 % CI 0.83–5.06, P = 0.117). Antiplatelet therapy discontinuation was more frequent in patients with LAPR as compared to those with no LAPR (21.6 vs. 9.1 %, P = 0.0008). In conclusion, early point-of-care on-aspirin platelet reactivity testing in ACS may identify patients with increased risk of minor bleeding events and subsequent discontinuation of antiplatelet therapy. The possible impact of LAPR on major bleeding needs to be determined in larger trials.