IMPROVE-STEMI: pPCI Plus Low-dose r-SK in STEMI

This is a multicenter, prospective, pragmatic, randomized controlled trial (IMPROVE-STEMI) aiming to evaluate the efficacy and safety of intracoronary low-dose recombinant streptokinase combined with primary percutaneous coronary intervention (pPCI) in patients with acute ST-segment elevation myocardial infarction (STEMI). A total of 3,300 patients will be enrolled, consisting of a core randomized study (300 patients, 1:1 ratio to pPCI + recombinant streptokinase vs. pPCI alone) and an extended observational study (3,000 patients receiving pPCI + recombinant streptokinase). The primary outcome measure is the coronary angiography-derived index of microcirculatory resistance (caIMR) immediately after the procedure. Secondary outcomes include the incidence of major adverse cardiovascular events (MACE) at 1 year, TIMI flow grade, corrected TIMI frame count (CTFC), and myocardial salvage index. The study duration is 24 months after the first patient enrollment, with follow-up visits scheduled at Day 5, Week 4, Week 12, Week 24, and Week 52.