Non-stenting strategy is not inferior to stent implantation in patients with acute ST-segment elevated myocardial infarction and high thrombus burden and intermediate stenotic culprit lesion

Background: According to European Society of Cardiology (ESC) as well as American College of Cardiology/American Heart Association (ACC/AHA) guidelines, primary stenting is recommended for patients with acute ST-segment elevation myocardial infarction (STEMI); however, in-stent thrombosis is a life-threatening early adverse event that could lead to acute myocardial infarction (AMI) or even cardiac death. On the other hand, in-stent restenosis is a late adverse event that could result in recurrent readmission and revascularization. We compared a non-stenting (NS) strategy to a stenting (S) strategy in terms of incidence of major adverse cardiac events (MACEs) for patients with acute STEMI and high thrombus burden.

Methods: We performed a post hoc analysis of our prior multicenter, prospective cohort study (ChiCTR1800019923) among 51 eligible patients with acute STEMI and high thrombus burden. All participants received percutaneous coronary intervention (PCI) with a deferred-stenting strategy (second procedure performed within 48-72 h after primary PCI). Either NS or S strategies were carried out among patients. Primary outcomes were follow-ups of MACEs at 1, 3, 6, and 12 months. Intravenous ultrasound (IVUS) and quantitative flow ratio (QFR) evaluation were performed.

Results: In our post hoc analysis of 51 patients (21 with NS and 30 with S), baseline clinical and interventional characteristics were well matched between the 2 groups, to the exception of culprit lesion length. Incidence of MACEs was not significantly different between the 2 strategies in-hospital (P=0.56) and in follow-ups at 1 (P=0.41), 3 (free of events), 6 (P=0.71), and 12 (P=0.68) months. Culprit lesions of NS tended to be "low-risk" [minimum lumen area (MLA) 4.27±1.02 vs. 3.80±1.32 mm2, P=0.36] and plaque burden (70.79%±6.46% vs. 76.97%±6.76%, P=0.03) when compared with culprit lesions of S in IVUS evaluation. Evaluation of QFR showed more sufficient physiological reperfusion improvement with NS than with S [two-dimensional (2D) QFR: 0.85±0.09 vs. 0.79±0.13, P=0.10 and 3D QFR: 0.86±0.08 vs. 0.78±0.15, P=0.02].

Conclusions: The NS strategy did not increase MACEs in-hospital and at 1, 3, 6, and 12 months. The NS can be a safe option when meeting certain criteria for patients with STEMI and a high thrombus burden.