Biomarkers of platelet activation and cardiovascular risk in the DAPT trial.

Prolonged use of dual antiplatelet therapy (DAPT) post-percutaneous coronary intervention (PCI) has been shown to reduce the risk of major adverse cardiovascular events (MACE), but with increased bleeding. It remains unknown whether biomarkers of platelet activation may be useful for identifying patients at increased risk of MACE. The DAPT study was a randomized trial of 12 versus 30 months of DAPT in patients who underwent PCI. Serum biomarkers [myeloid-related protein (MRP)-8/14, P-selectin, soluble CD-40 ligand (sCD40L)] were assessed in 1399 patients early post-PCI. On-treatment platelet reactivity index (PRI) using VASP phosphorylation was assessed in 443 patients randomized to continued DAPT at 1 year. MACE was defined as CV death, MI, or ischemic stroke. Multivariable models were adjusted for baseline characteristics, index event, and stent type. A stepwise increase in the risk of MACE was observed with increasing tertiles of both MRP-8/14 and P-selectin (p-trend = 0.04 for both). After multivariable adjustment, the adjusted HR (95% CI) for MACE in patients in the top tertile was 1.94 (1.14-3.30) for MRP-8/14 and 1.62 (0.99-2.64) for P-selectin. In contrast, baseline sCD40L was not associated with CV risk. Among patients randomized to continued DAPT, higher on-treatment platelet reactivity was not significantly associated with risk of MACE (p-trend = 0.32; adj-HR T3 vs. T1 1.54, 95% CI 0.20-12.18) or bleeding (P-trend = 0.17; adj-HR 0.25, 95% CI 0.05-1.21). MRP-8/14 and soluble P-selectin may be useful for identifying patients at increased risk of MACE after PCI. The utility of on-treatment platelet function testing requires further study.Clinical Trial Registration https://www.clinicaltrials.gov . Unique identifier NCT00977938.