Impact of thrombocytopenia on bleeding and cardiovascular outcomes in patients undergoing percutaneous coronary intervention with dual-antiplatelet therapy

BACKGROUND: Patients with thrombocytopenia undergoing percutaneous coronary intervention (PCI) are at an elevated risk of bleeding and adverse cardiovascular events due to dual-antiplatelet therapy (DAPT). Limited data exist on the safety of DAPT in this subset of patients. METHODS: This single-centre prospective cohort study was conducted at SMS Medical College, Jaipur, India, over 12 months (March 2024-March 2025). A total of 368 patients with baseline (pre-PCI) thrombocytopenia who underwent elective or emergency PCI while on DAPT were enrolled. DAPT comprised aspirin plus a P2Y12 inhibitor: clopidogrel in 317 patients (86.1%), ticagrelor in 48 (13.0%), and prasugrel in 3 (0.8%), with the choice based on clinician discretion; the distribution did not differ significantly across thrombocytopenia grades (p = 0.204). DAPT was generally maintained for 6-12 months per institutional protocol, without a standardized de-escalation strategy. Thrombocytopenia was classified based on pre-procedural platelet counts as mild (100,000-150,000/mm³; n = 237, 64.4%), moderate (50,000-100,000/mm³; n = 104, 28.2%), or severe (30,000-50,000/mm³; n = 27, 7.3%). The primary outcomes were major adverse cardiovascular events (MACE), defined as a composite of total death, myocardial infarction (MI), coronary revascularization, stroke, and hospitalization due to heart failure; and bleeding events assessed using Bleeding Academic Research Consortium (BARC) criteria. Secondary outcomes included in-hospital mortality, stent thrombosis, target vessel revascularization, and post-PCI MI. Follow-up was conducted at 1, 2, and 6 months post-PCI. Multivariate logistic regression was used to adjust for confounders across three sequential models (demographics; clinical variables; procedural outcomes). RESULTS: Severe thrombocytopenia independently predicted higher risks for MACE (HR: 2.30, CI: 1.89-2.81) and bleeding (HR: 2.88, CI: 2.37-3.49) across all models. Mild thrombocytopenia showed no significant risk after adjustment for confounders. Patients with moderate thrombocytopenia demonstrated consistent risks for both outcomes. Smoking and history of PCI/MI significantly correlated with thrombocytopenia severity (p < 0.01). CONCLUSION: Moderate and severe thrombocytopenia are independently associated with increased risks of bleeding and cardiovascular events in patients on DAPT post-PCI. These observational findings support the incorporation of thrombocytopenia severity into existing risk stratification frameworks; however, as this study did not evaluate alternative management strategies, prospective randomized trials are needed to determine whether modified antiplatelet regimens can improve outcomes in this high-risk population.