Comparison of Immediate With Delayed Stenting Using the Minimalist Immediate Mechanical Intervention Approach in Acute ST-Segment–Elevation Myocardial Infarction

Abstract

Background-Delayed stent implantation after restoration of normal epicardial flow by a minimalist immediate mechanical intervention aims to decrease the rate of distal embolization and impaired myocardial reperfusion after percutaneous coronary intervention. We sought to confirm whether a delayed stenting (DS) approach (24-48 hours) improves myocardial reperfusion, versus immediate stenting, in patients with acute ST-segment-elevation myocardial infarction undergoing primary percutaneous coronary intervention. Methods and Results-In the prospective, randomized, open-label minimalist immediate mechanical intervention (MIMI)trial, patients (n=140) with ST-segment-elevation myocardial infarction ≤12 hours were randomized to immediate stenting (n=73) or DS (n=67) after Thrombolysis In Myocardial Infarction 3 flow restoration by thrombus aspiration. Patients in the DS group underwent a second coronary arteriography for stent implantation a median of 36 hours (interquartile range 29-46) after randomization. The primary end point was microvascular obstruction (% left ventricular mass) on cardiac magnetic resonance imaging performed 5 days (interquartile range 4-6) after the first procedure. There was a nonsignificant trend toward lower microvascular obstruction in the immediate stenting group compared with DS group (1.88% versus 3.96%; P=0.051), which became significant after adjustment for the area at risk (P=0.049). Median infarct weight, left ventricular ejection fraction, and infarct size did not differ between groups. No difference in 6-month outcomes was apparent for the rate of major cardiovascular and cerebral events. Conclusions-The

2018 ESC/EACTS Guidelines on myocardial revascularization

“…Delaying stenting in primary PCI has been investigated as an option to reduce microvascular obstruction (MVO) and preserve microcirculatory function in two small trials with conflicting results. 219,220 More recently, in the larger deferred vs. conventional stent implantation in patients with STEMI [The Third DANish Study of Optimal Acute Treatment of Patients with ST-segment Elevation Myocardial Infarction: DEFERred stent implantation in connection with primary PCI (DANAMI 3-DEFER)] trial in 1215 STEMI patients, there was no effect on the primary clinical outcome (composite of death, non-fatal MI, or ischaemia-driven revascularization of non-IRA lesions) over a median follow-up of 42 months. 221 Routine deferred stenting was associated with a higher risk of TVR.…”

Deferred Versus Immediate Stenting in Patients With ST‐Segment Elevation Myocardial Infarction: A Systematic Review and Meta‐Analysis

“…Several subsequent observational studies have suggested that deferred stenting was associated with higher rates of procedural success, higher 6‐month left ventricular ejection fraction (LVEF), and lower rates of adverse events compared with immediate stenting . Recently, findings from new randomized controlled trials (RCTs) were available, showing some inconsistent results with previous observational studies . To provide a clearer understanding of this important issue, we performed a meta‐analysis of deferred vs immediate stenting in patients with acute STEMI.…”

Cardiovascular Diagnosis and Therapy (CDT) Editorial: the Minimalist Immediate Mechanical Intervention study

“…However, since stent implantation may cause intraprocedural thrombotic complications (IPTEs), including distal embolization of thrombus leading to microvascular obstruction (MVO) and no-reflow (2,3) some clinicians have questioned whether immediate stent implantation is mandated in all patients, or instead, whether stent implantation could be deferred for a limited period to enable the beneficial effects of restored blood flow and medical therapy. With this in mind, a number of clinical investigations of deferred stenting (DS) strategies have been assessed (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). This was the focus of the Minimalist Immediate Mechanical Intervention (MIMI) trial (14).…”

“…These are associated with a larger infarct size and an adverse prognosis (21). The hypothesis underpinning a DS approach is the potential to reduce coronary thrombus burden after initial stabilization of infarct related lesion and preserve microvascular function, therefore reducing the likelihood of slow and no reflow and MVO (14)(15)(16).…”

“…In a recent issue of Circulation Cardiovascular Interventions the MIMI investigators reported their experience in a randomised trial of immediate stenting versus DS in 160 patients (n=140 randomised in 16 hospitals) presenting within 12 hours of STEMI (14). They tested the hypothesis that DS improves myocardial perfusion compared to immediate stenting in the setting of primary PCI for acute STEMI.…”