Strategy of delayed intervention without stent implantation in myocardial infarction with ST segment elevation caused by massive thrombosis of the infarct-related artery

Aim . TIntroduction. To evaluate in-hospital angiographic and five-year posthospital clinical outcomes of percutaneous intervention strategy without stent implantation with immediate coronary artery stenting technique in STEMI patients with massive coronary thrombosis. Material and methods . The study enrolled 116 patients with primary STEMI myocardial infarction with the signs of massive thrombosis in the lumen of the main epicardial coronary artery with TIMI thrombus grade greater than 3 after antegrade blood flow restoration. In the 1st group of delayed intervention at the primary stage the blood flow was restored by small diameter balloon inflation and/ or manual vacuum thrombus aspiration until stable TIMI grade 3 blood flow was achieved, at control CAG on day 5-6 in 36 people the stent was not implanted due to insignificance of infarct-related coronary artery stenosis (stenosis less than 50% according to QCA). Immediate stent implantation was performed in 78 patients (group 2). The primary endpoint was the incidence of adverse cardiovascular events, including total mortality, recurrent myocardial infarction, repeated revascularization of the infarct-responsive artery. Secondary endpoint: frequency of achieving optimal myocardial perfusion as measured by angiography – TIMI blood flow and Myocardial Blush Grade. Results . The median follow-up period was 47 months. The incidence of the primary end point (MACE) was 15,8% in group 1 and 23,1% in group 2, with no statistically significant difference (p=0,408). Overall mortality (10,5% and 11,7%), the rate of repeat myocardial infarction (2,6% and 5,1%), and the rate of repeat target vessel revascularization (2,6% and 6,4%) were without significant advantage between subgroups. Optimal reperfusion (TIMI-3 and Myocardial Blush Grade 2-3 after primary procedure was achieved in significantly (p=0,02) more patients in group 1 (89%) than in group 2 (69,2%) ST segment resolution ≥70% after intervention was achieved in 87% of cases in group 1 and in 64,1% of cases in group 2 (p=0,011). Conclusion . In STEMI patients with massive coronary thrombosis, the method of delayed percutaneous intervention increases the rate of achieving optimal blood flow and allows avoiding stent implantation in the infarct-related artery in 50% of cases as compared to the method of immediate stenting. Both methods have comparable hospital and five-year clinical risks.