Association of ticagrelor vs clopidogrel with net adverse clinical events in patients with mild thrombocytopenia undergoing PCI

Abstract Backgrounds Current guidelines recommend aspirin plus ticagrelor as the preferred dual antiplatelet therapy (DAPT) for managing ST-elevation myocardial infarction (STEMI). However, there is a lack of consensus or guidelines to direct clinicians on managing patients with mild thrombocytopenia, defined as a platelet count of 100~150×109/L, undergoing percutaneous coronary intervention (PCI). Purpose This study aims to investigate the association between ticagrelor and clopidogrel with ischemic and hemorrhagic events for patients with mild thrombocytopenia undergoing PCI. Methods A retrospective cohort study of patients with mild thrombocytopenia undergoing PCI who received DAPT consisting of aspirin and a P2Y12 receptor antagonist (includinig clopidogrel or ticagrelor) was conducted using Health and Medical Big Data Super Platform from January 2010 to June 2023. All patients meeting the criteria were included in the analysis, with a follow-up of at least one year. Propensity Score Matching (PSM) was performed to equalize the effects of following characteristics: age, sex, hypertension, diabetes, dyslipidemia, stroke, atrial fibrillation, Killip class, percutaneous coronary intervention (PCI), beta-blockers, statins, calcium channel blockers (CCB), angiotensin-converting enzyme inhibitor or angiotensin receptor blocker (ACEI or ARB), angiotensin receptor-neprilysin inhibitor (ARNI), diuretic, organic nitrates, and oral anticoagulation. The primary endpoint was net adverse clinical events (NACE) at 1 year, composed of ischemic events (recurrent myocardial infarction or ischemic stroke), Bleeding Academic Research Consortium (BARC) classification ≥ 3, and cardiac death. Secondary outcomes included the components of NACE. Results A total of 3647 patients met the inclusion criteria, with 2684 receiving aspirin plus clopidogrel and 963 receiving aspirin plus ticagrelor, matched by a 1:3 ratio using the PSM method. Demographic characteristics were well balanced between the clopidogrel and ticagrelor groups. The 1-year risk of NACE did not significantly differ between ticagrelor and clopidogrel (11.1% vs. 8.4%, p=0.370). Similarly, there was no significant difference in the risk of cardiac death (7.3% vs. 4.2%, p=0.720), recurrent myocardial infarction (9.3% vs. 5.8%, p=0.550), ischemic stroke (8.8% vs. 6.7%, p=0.055), or BARC type ≥ 3 bleeding (7.9% vs. 4.5%, p=0.990). Conclusion In routine clinical practice, among patients with a platelet count of 100~150×109/L undergoing PCI, ticagrelor compared with clopidogrel was not associated with a significant difference in the risk of NACE at 1 year. Further research is warranted to assess whether ticagrelor is more effective than clopidogrel in this setting, considering potential unmeasured confounders.