A Randomized Trial of Deferred Stenting Versus Immediate Stenting to Prevent No- or Slow Reflow in Acute ST-Elevation Myocardial Infarction (DEFER-STEMI)

Study Questions:

What is the impact of deferred stenting on no-reflow and myocardial salvage in primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI)?


This was a prospective single-center, randomized, controlled, proof-of-concept trial in reperfused STEMI patients with ≥1 risk factor for no-reflow. Randomization was to deferred stenting with an intention-to-stent 4-16 hours later or conventional treatment with immediate stenting. The primary outcome was the incidence of no/slow-reflow (TIMI ≤2). Cardiac magnetic resonance imaging (MRI) was performed 2 days and 6 months post-MI. Myocardial salvage was the final infarct size indexed to the initial area at risk. Odds ratios and 95% confidence intervals for treatment effect outcomes were assessed using exact logistic regression for binary outcomes and ordinal logistic regression for ordinal outcomes.


Of 411 STEMI patients (March 11, 2012 to November 21, 2012), 101 patients (mean age 60 years, 69% male) were randomized (n = 52 deferred group, n = 49 immediate stenting). The median (IQR) time to the second procedure in the deferred group was 9 (6, 12) hours. 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]. TIMI coronary flow grades at the end of PCI were higher in the deferred stenting group (p = 0.018). Recurrent STEMI occurred in two patients in the deferred group before the second procedure. Myocardial salvage index at 6 months was greater in the deferred group [68 (54, 82%) vs. 56 (31, 72%); p = 0.031].


The authors concluded that in high-risk STEMI patients, deferred stenting in primary PCI reduced no-reflow and increased myocardial salvage.


This pilot trial reports that deferred completion of PCI in selected STEMI patients reduced no-reflow, distal embolization, and intraprocedural thrombotic complications compared to conventional treatment with immediate stenting. Final coronary flow grade and myocardial blush grade were also better in the deferred group. The rate of recurrent ischemia in the deferred group was low and, considering the limited sample size, one cannot exclude the possibility that this was due to chance. These results may support the rationale for a large multicenter clinical trial to assess the patient experience, health outcomes, quality of life, and cost-effectiveness of early deferred completion of PCI after reperfusion versus conventional treatment in STEMI patients at risk of no-reflow. Only such a trial can address the true efficacy and safety of deferred stenting in this population.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention

Keywords: Myocardial Infarction, Quality of Life, Risk Factors, Myocardial Reperfusion, Stents, Percutaneous Coronary Intervention

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