Deferred Versus Immediate Stenting in ST-Segment Elevation Myocardial Infarction with High Thrombus Burden: A Retrospective Observational Cohort Study

Abstract

Objectives: To compare the angiographic, functional, and clinical outcomes of deferred versus immediate stenting strategies in patients presenting with ST-segment elevation myocardial infarction (STEMI) and high thrombus burden undergoing primary percutaneous coronary intervention (PCI). Methodology: This retrospective observational cohort study was conducted at the Department of Cardiology, Lady Reading Hospital, Peshawar, Pakistan, between January 2022 and December 2024. A total of 450 adult STEMI patients with angiographically confirmed high thrombus burden (TIMI thrombus grade ≥3) undergoing primary PCI were included. Patients were categorized into immediate stenting (n=218) and deferred stenting (n=232) groups. Deferred stenting involved initial reperfusion followed by delayed stent implantation after 24–72 hours of intensive antithrombotic therapy. The primary endpoint was the occurrence of no-reflow/slow-reflow phenomenon. Secondary outcomes included final TIMI flow grade 3 achievement, major adverse cardiac events (MACE) at 30 days and 6 months. Results: Deferred stenting was associated with a significantly lower incidence of no-reflow/slow-reflow compared with immediate stenting (5.2% vs. 28.9%, p<0.001). Final TIMI flow grade 3 achievement was significantly higher in the deferred group (94.8% vs. 71.1%, p<0.001). Patients undergoing deferred stenting demonstrated superior left ventricular systolic function (LVF) recovery both at discharge (49.7±5.6% vs. 44.2±7.1%, p<0.001) and at 6-month follow-up (55.3±5.3% vs. 50.2±5.6%, p<0.001). While 30-day MACE rates were not significantly different between groups (9.1% vs. 12.4%, p=0.252), the deferred stenting group showed significantly lower MACE rates at 6 months (10.8% vs. 20.2%, p=0.006). Conclusion: In STEMI patients with high thrombus burden, deferred stenting was associated with improved myocardial perfusion, better recovery of LVF, and lower mid-term adverse cardiovascular events compared with immediate stenting, without significant increase in bleeding or procedural complications. Deferred stenting may therefore represent a beneficial strategy in carefully selected high-risk patients undergoing primary PCI.