Delayed versus immediate stenting for the treatment of ST-elevation acute myocardial infarction with a high thrombus burden.

OBJECTIVES: High thrombus burden (HTB) is an independent predictor of no flow or low reflow during a primary percutaneous coronary intervention. This study aimed to compare immediate versus delayed stenting in ST-elevation myocardial infarction (STEMI) patients with HTB. METHODS: In this retrospective, nonrandomized study, a total of 103 consecutive STEMI patients with HTB (thrombus burden score, TBS≥3) were assigned to immediate stenting (IS group, n=50) or delayed stenting (DS group, n=53), a decision that was made at the discretion of the operators. The IS group received stent placement immediately, whereas the DS group was given enhanced antithrombotic therapies and deferred for stenting at least 7 days later. Thrombolysis in myocardial infarction (TIMI) flow score (TIMIs) and myocardial blush grade (MBG) were assessed angiographically and the left ventricular ejection fraction (LVEF) was measured echocardiographically. The major adverse cardiac event (MACE) was the composite of cardiac death, reinfarction, target vessel revascularization, heart failure, and major bleeding. RESULTS: The DS group had better immediate MBG (P<0.001), higher LVEF at 6 months (P=0.044), and lower MACE rate at 1 year (log-rank P=0.008). Multiple logistic regression identified immediate stenting (odds ratio 7.4, 95% confidence interval 2.1-26.6; P=0.002) and high TBS (odds ratio 2.6, 95% confidence interval 1.1-6.5, P=0.034) as the independent predictors of poor myocardial perfusion. Delayed stenting benefited the male patients, those who were of a younger age, and those who had a larger infarction-related artery, higher TBS, or lower TIMIs in terms of MBG or MACE. Delayed stenting avoided stent implantation of the infarct-related artery in 12/53 (22.6%) patients particularly in the younger patients. CONCLUSION: For STEMI patients with HTB who have undergone initial thrombectomy, delayed stenting is safe and feasible, and may be associated with better immediate myocardial perfusion, more LV function recovery, and less occurrence of MACE at the 1-year follow-up.