Deferred versus Immediate Stenting in ST-segment Elevation Myocardial Infarction Patients with High Thrombus Burden: A Randomized Clinical Trial Using Three-dimensional Speckle Tracking Echocardiography

Abstract Objectives: The optimal timing of stent implantation in ST-segment elevation myocardial infarction (STEMI) with high thrombus burden remains uncertain. Immediate stenting carries a risk of distal embolization and no-reflow, whereas deferred stenting may facilitate improved microvascular recovery. This study compared angiographic and echocardiographic outcomes of immediate versus deferred stenting using three-dimensional speckle tracking echocardiography (3D-STE). Materials and Methods: In this randomized clinical trial, 115 STEMI patients with high thrombus burden were allocated to immediate stenting ( n = 60) or deferred stenting after dual antiplatelet therapy plus enoxaparin ( n = 55). Primary endpoints were final thrombolysis in myocardial infarction (TIMI) flow, myocardial blush grade (MBG), and left ventricular ejection fraction (LVEF) by 3D-STE. Secondary endpoints included global strain parameters and major adverse cardiovascular events (MACE) at 6 months. Results: Deferred stenting achieved higher TIMI III flow (76.4% vs. 60.0%, P < 0.001) and MBG 3 (63.6% vs. 41.7%, P = 0.0025). Both groups showed improved LVEF at 6 months, with greater gains in the deferred group (EF change: 14.05% vs. 12.89%, P = 0.043). Favorable but nonsignificant trends were noted in global longitudinal, circumferential, and radial strain. MACE rates were similar between groups (34.5% vs. 41.7%, P = 0.45). Conclusions: Deferred stenting in STEMI patients with high thrombus burden enhanced angiographic reperfusion and improved recovery of left ventricular function without reducing short-term MACE. These findings suggest deferred stenting as a feasible strategy to optimize myocardial reperfusion, warranting larger, long-term trials to evaluate its prognostic impact.