Increased risk of adverse events in patients with low-on clopidogrel platelet reactivity after percutaneous coronary intervention: A systematic review and meta-analysis.

BACKGROUND: Clinical evidence has been controversial regarding the influence of low platelet reactivity (LPR), ischemic and bleeding outcomes among patients receiving coronary stent implantation. Hence, the present study performed a meta-analysis to systematically evaluate the significance of LPR on adverse cardiovascular events. METHODS: MEDLINE, EMBASE and CENTRAL databases were searched up to November 2020 for relevant studies including patients with acute coronary syndrome undergoing percutaneous coronary intervention. LPR was the exposed arm while the non-LPR group represented the control. The primary outcome of interest was bleeding risk including major and minor bleeding events. Secondary outcomes included all-cause mortality, repeated revascularization, nonfatal myocardial infarction, and stent thrombosis. Study-level outcomes were evaluated in random-effect models. RESULTS: A total of 20 studies with 19,064 patients were included. Pooled analysis showed that LPR was associated with an increased bleeding risk (relative risk [RR] 2.80, 95% confidence interval [CI] 1.95-4.02, p < 0.01). Patients with LPR had a lower risk of non-fatal myocardial infarction (RR 0.59, 95% CI 0.38-0.91, p < 0.05) and of serious vascular events (RR 0.50, 95% CI 0.30-0.84, p < 0.01). CONCLUSIONS: Low platelet reactivity is associated with an increased bleeding risk of patients who underwent coronary stent implantation. The results suggest possible benefits of this marker in risk stratification, with potential improvement in risk prediction. There are potential advantages using combinations with other factors in prediction models, however, they require further study. PROSPERO registration number: CRD42019136393).