A randomized trial of deferred stenting versus immediate stenting to prevent no- or slow-reflow in acute ST-segment elevation myocardial infarction (DEFER-STEMI)

Abstract

Objectives: The aim of this study was to assess whether deferred stenting might reduce no-reflow and salvage myocardium in primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI).

Background: No-reflow is associated with adverse outcomes in STEMI.

Methods: This was a prospective, single-center, randomized, controlled, proof-of-concept trial in reperfused STEMI patients with ≥1 risk factors for no-reflow. Randomization was to deferred stenting with an intention-to-stent 4 to 16 h later or conventional treatment with immediate stenting. The primary outcome was the incidence of no-/slow-reflow (Thrombolysis In Myocardial Infarction ≤2). Cardiac magnetic resonance imaging was performed 2 days and 6 months after myocardial infarction. Myocardial salvage was the final infarct size indexed to the initial area at risk.

Results: Of 411 STEMI patients (March 11, 2012 to November 21, 2012), 101 patients (mean age, 60 years; 69% male) were randomized (52 to the deferred stenting group, 49 to the immediate stenting). The median (interquartile range [IQR]) time to the second procedure in the deferred stenting group was 9 h (IQR: 6 to 12 h). Fewer patients in the deferred stenting group had no-/slow-reflow (14 [29%] vs. 3 [6%]; p = 0.006), no reflow (7 [14%] vs. 1 [2%]; p = 0.052) and intraprocedural thrombotic events (16 [33%] vs. 5 [10%]; p = 0.010). Thrombolysis In Myocardial Infarction coronary flow grades at the end of PCI were higher in the deferred stenting group (p = 0.018). Recurrent STEMI occurred in 2 patients in the deferred stenting group before the second procedure. Myocardial salvage index at 6 months was greater in the deferred stenting group (68 [IQR: 54% to 82%] vs. 56 [IQR: 31% to 72%]; p = 0.031].

Conclusions: In high-risk STEMI patients, deferred stenting in primary PCI reduced no-reflow and increased myocardial salvage. (Deferred Stent Trial in STEMI; NCT01717573).

Keywords: deferred stenting; myocardial infarction; myocardial salvage; no-reflow; primary percutaneous coronary intervention.

Figure 1

Study Flow Diagram MRI = magnetic resonance imaging; PCI = percutaneous coronary intervention; STEMI = ST-segment elevation myocardial infarction.

Figure 2

Two Patients With Acute Anterior STEMI One patient was treated by conventional primary PCI with immediate stenting and the other was treated with initial aspiration thrombectomy and then deferred stenting. Each patient had similar ischemic times (147 min and 163 min), and both were treated with similar antithrombotic therapies including 300 mg aspirin, 600 mg clopidogrel, 5,000 IU heparin, and intravenous tirofiban. (A) Usual care with immediate stenting. The angiogram (left) revealed proximal occlusion of the left anterior descending artery (green arrow, Thrombolysis In Myocardial Infarction [TIMI] grade 0 flow). Primary PCI was complicated by no-reflow (TIMI grade 1 flow). Two days later, cardiac MRI was performed. Cine MRI (middle left) revealed an extensive anteroapical left ventricular wall motion abnormality. Matched diastolic phase images obtained using late gadolinium enhancement imaging (middle right) revealed a transmural infarction with microvascular obstruction (orange arrows). The area at risk revealed by T2-weighted imaging (right) was 42.2% of left ventricular mass, and the acute infarct size revealed by late gadolinium enhancement (middle right) was 39.6%. Microvascular obstruction depicted as the central dark zone within the infarct territory was 8.2% of the left ventricular mass. The left ventricular ejection fraction and end-systolic volume were 43.7% and 52.3 ml/m², respectively. Six-month follow-up MRI revealed that the final infarct size was 32.1% of the left ventricular mass, and therefore myocardial salvage was 10.1%. (B) Deferred PCI. The angiogram (left) revealed a proximal occlusion of the left anterior descending artery (green arrow, TIMI grade 0 flow). Primary PCI in the left anterior descending coronary artery with deferred stent implantation was uncomplicated. Two days later, cardiac MRI was performed. Cine MRI (middle left) revealed an extensive anteroapical left ventricular wall motion abnormality. Despite similar ischemic times in both patients, this patient had minimal evidence of infarction on late gadolinium enhancement imaging (middle right) and no microvascular obstruction. The acute infarct size was 8.4% of the left ventricular mass. The area at risk (right) was similar between cases, at 43.1%, as was the left ventricular ejection fraction and normalized end-systolic volume, measured at 43.5% and 57.1 ml/m², respectively, consistent with stunned but viable myocardium. Six-month follow-up MRI revealed that the final infarct size was 1.7% of the left ventricular mass, and therefore myocardial salvage was 41.4%.