The recommended treatment for ST elevation acute myocardial infarction (STEMI) is early PCI, typically stenting. However, stent implantation always involves the risk of intravascular complications, such as stent thrombosis or restenosis.
Sometimes stable flow is restored to the target vessel after initial PCI and we can omit stenting when there is no angiographically significant residual stenosis.
Still, the revascularization of atherosclerotic plaque with non-significant stenosis which appear “vulnerable” mainly due to lipid-rich cores (high risk atherosclerosis) remains of study interest, seeing as stenting has not reduced culprit vessel related events vs. optimal medical treatment (PROSPECT ABSORB 2020).
The DANAMI 3 DEFER is a substudy of the DANAMI-3, which included 1215 STEMI patients randomized to conventional stenting vs. deferred stenting, which showed no benefits for the deferred strategy vs. patients who were randomized to deferred stenting but did not receive a stent.
This study recently published in Eurointervention, is a post hoc analysis of the DANAMI-3-DEFER, which looked at the safety of stenting omission in STEMI by assessing clinical outcomes.
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It included patients treated with thrombectomy/balloon angioplasty (POBA) followed with IIB/IIIA after index intervention, re-assessed at 24/48 hrs. Those presenting ≤30% angiographically stable stenosis, absence of thrombi or dissection, were included in the non-stenting group.
The primary end point was a composite of all-cause mortality, repeat MI, and target vessel revascularization (TVR) at mean 3.4 years.
This post-hoc analysis included 674 patients with different baseline characteristics, with a lower percentage of diabetes and hyperlipidemia among the no-stenting patients; target vessel was often a main coronary artery and there was lower prevalence of multivessel disease.
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84 patients randomized to deferred stenting did not receive a stent (71% POBA, 7% thrombectomy and 21% no intervention). There were no significant differences in composite end point for the unstented patients: it was 14% vs. 16% for the immediate stenting group (HR 0.87, CI 95% 0.48-1.60, p=0.66), with no differences in TVR (HR 0.59, CI 95% 0.14-2.52, p=0.48) or repeat MI.
Conclusions
This post hoc analysis of the DANAMI-3-DEFER showed unstented patients had a very low number of events and did not present significant differences at followup. However, we should bear in mind baseline characteristics were different between the groups. As hypotheses generator, these outcomes speak of the potential safety of stenting omission after STEMI in a highly selected population (branch compromise, less diabetes and multivessel disease) with non-significant residual stenosis and conserved flow, which prevents stent complications such as thrombosis and restenosis.
Therefore, clinical safety call for further randomized study to better assess alternative strategies to stenting in STEMI patients with non-significant stenosis.
Dr. Omar Tupayachi.
Member of the Editorial Board, SOLACI.org
Reference: EuroIntervention. 2022 Mar 16;EIJ-D-21-00950. doi: 10.4244/EIJ-D-21-00950.
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