Adjunctive Intracoronary Thrombolysis During Primary Percutaneous Coronary Intervention for STEMI

Background: Distal embolization and microvascular obstruction remain important limitations of primary percutaneous coronary intervention (PCI) in ST-segment elevation myocardial infarction (STEMI), contributing to impaired myocardial reperfusion and adverse cardiovascular outcomes. We performed an updated systematic review and meta-analysis of randomized controlled trials evaluating adjunctive intracoronary thrombolysis during primary PCI for STEMI. Methods: A systematic literature search through Scopus, Embase, and the Cochrane Library was performed through May 15, 2026. Randomized controlled trials comparing adjunctive intracoronary thrombolysis versus placebo or conventional PCI in STEMI patients undergoing primary PCI were included. Thrombolytic agents included prourokinase, urokinase, alteplase, and tenecteplase. Outcomes included major adverse cardiovascular events (MACE), myocardial reperfusion parameters, and bleeding complications. Pooled risk ratios (RR) with 95% confidence intervals (CI) were calculated using random-effects models. Prespecified subgroup analyses were performed according to thrombolytic agent. Results: Eleven randomized controlled trials comprising 2,457 patients were included. Adjunctive intracoronary thrombolysis reduced MACE at 3-6 months (RR 0.64, 95% CI 0.45-0.91; p=0.01), with no difference in 30-day MACE (RR 1.00, 95% CI 0.60-1.67; p=0.99). Compared with placebo/conventional PCI, intracoronary thrombolysis improved post-PCI TIMI 3 flow (RR 1.06, 95% CI 1.01-1.12; p=0.02), myocardial blush grade 2-3 (RR 1.23, 95% CI 1.07-1.41; p=0.004), and ST-segment resolution >70% at 60-90 minutes (RR 1.24, 95% CI 1.12-1.38; p<0.0001). The reduction in intermediate-term MACE was driven primarily by prourokinase/urokinase-based strategies (RR 0.53, 95% CI 0.36-0.78). Major bleeding was not increased (RR 1.23, 95% CI 0.55-2.74; p=0.62). Conclusions: Adjunctive intracoronary thrombolysis during primary PCI improved myocardial reperfusion and reduced intermediate-term cardiovascular events without increasing major bleeding. The greatest benefit was observed with prourokinase/urokinase-based strategies. Further randomized studies are needed to identify the optimal thrombolytic agent and define the role of intracoronary thrombolysis in contemporary STEMI reperfusion practice.