Safety and efficacy of low-dose intracoronary thrombolysis during primary percutaneous coronary intervention in patients with ST elevation myocardial infarction: A meta-analysis of randomized trials

In patients with ST elevation myocardial infarction (STEMI), intracoronary thrombolysis (ICT) may reduce thrombotic burden and microvascular obstruction in the infarct-related artery. We performed a meta-analysis to evaluate the role of adjunctive low-dose ICT during primary percutaneous coronary intervention (PPCI) in improving clinical outcomes and indices of microvascular function. We searched electronic databases (Cochrane, EMBASE, Medline; inception to October 2023) for randomized controlled trials (RCTs) evaluating the effects of adjunctive ICT in STEMI patients undergoing PPCI, compared with placebo or usual care. Study-level data on efficacy and safety outcomes were pooled using a fixed-effect model. The primary outcome was major adverse cardiovascular events (MACE). A total of 8 RCTs were included, comprising a total of 1,208 patients. Compared with placebo or usual care, ICT was associated with a trend towards lower MACE (11.3% vs. 15.1%; odds ratio [OR] 0.73, 95% confidence interval [CI] 0.51 to 1.04). Infarct size (mean difference [MD] -1.98, 95% CI -3.68 to -0.27; p=0.02), ST-segment resolution (MD: 6.06, 95% CI: 0.69 to 11.43; p=0.03) and corrected TIMI frame count (MD: -2.26, 95% CI: -4.03 to -0.48; p=0.01; I2=78%). The odds for major (0.7% vs. 0.7%; OR 0.94, 95% CI 0.24 to 3.7; p=0.93) and minor bleeding (7.7% vs. 4.3%; OR 1.81, 95% CI 0.87 to 3.76; p=0.11) were similar between the two groups. Adjunctive low-dose ICT during PPCI is safe, associated with a trend towards lower MACE, and may improve surrogate markers of microvascular function. These hypothesis-generating findings warrant validation in larger, adequately powered randomized trials.