NHLBI-Sponsored Randomized Trial of Postconditioning During Primary Percutaneous Coronary Intervention for ST-Elevation Myocardial Infarction

Abstract

Rationale: Postconditioning (PostC) at the time of primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) may reduce infarct size and improve myocardial salvage. However, clinical trials have shown inconsistent benefit. Objective: We performed the first NHLBI-sponsored trial of PostC in the United States utilizing strict enrollment criteria to optimize the early benefits of PostC and assess its long-term effects on LV function. Methods and Results: We randomized 122 STEMI patients to PostC (Four, 30-sec. PTCA inflations / deflations) + PCI(n=65) vs. routine PCI (n=57). All subjects had an occluded major epicardial artery (TIMI= 0) with ischemic times between 1 and 6 hours with no evidence of preinfarction angina or collateral blood flow. Cardiac MRI measured at 2 days post-PCI showed no difference between the PostC group and Control in regards to infarct size (22.5 ± 14.5 g vs. 24.0 ± 18.5 g), myocardial salvage index (MSI) (30.3 ± 15.6% vs. 31.5 ± 23.6%) or mean LVEF. MRI at 12-months showed a significant recovery of LVEF in both groups (61.0 ± 11.4% and 61.4± 9.1%; p < 0.01). Subjects randomized to PostC experienced more favorable remodeling over 1 year (LVEDV = 157 ± 34 to 150 ± 38 ml) compared to the Control group (157 ± 40 to 165 ± 45 ml) (p < 0.03) and reduced microvascular obstruction (MVO) (p=0.05) on baseline MRI and significantly less adverse LV remodeling compared to Control subjects with MVO (p < 0.05). No significant adverse events were associated with the PostC protocol and all patients but one (hemorrhagic stroke) survived thru one-year of follow-up. Conclusions: We found no early benefit of PostC on infarct size, MSI and LV function compared to routine PCI. However, PostC was associated with improved LV remodeling at one year of follow-up, especially in subjects with MVO.

Effect of remote ischaemic conditioning on clinical outcomes in patients with acute myocardial infarction (CONDI-2/ERIC-PPCI): a single-blind randomised controlled trial

“…An alternative explanation could be that the primary effect of remote ischaemic conditioning was on post-STEMI left ventricular remodelling rather than acute myocardial infarct size—although this mechanism would contradict experimental animal studies, which have clearly shown a beneficial effect of remote ischaemic conditioning on reducing acute myocardial infarct size. Notably, a clinical study investigating the cardioprotective effects of ischaemic postconditioning in patients with STEMI treated by PPCI showed no effect on myocardial infarct size, but still found reduced severity of adverse left ventricular remodelling at 1 year of follow-up, especially in patients with microvascular obstruction 19 …”

Short‐term safety and long‐term benefits of stent postdilation after primary percutaneous coronary intervention: Results of a cohort study

“…On the other hand, PD is technically similar to the postconditioning process. A recent study by Traverse et al showed that postconditioning was associated with improved left ventricular remodeling at 1 year's follow‐up, especially in subjects with microvascular obstruction . This observation can justify our better outcome in the long‐term follow‐up in the PD group.…”

Ischemic postconditioning reduces infarct size and microvascular obstruction zone in acute ST-elevation myocardial infarction – a randomized study

“…In a recent study Traverse et al observed that postcon had no early beneficial effect on infarct size or left ventricular function compared with routine PCI. However, postconditioning was associated with improved left ventricular remodeling at 1-year follow-up, especially in subjects with the presence of MVO [36].…”