The Third DANish Study of Optimal Acute Treatment of Patients with ST-segment Elevation Myocardial Infarction: Ischemic Postconditioning During Primary PCI - DANAMI 3-iPOST

Description:

The goal of the trial was to compare the utility of ischemic postconditioning in patients undergoing primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI).

Contribution to the Literature: The DANAMI 3-iPOST trial suggests that ischemic postconditioning with short bursts of balloon occlusion immediately after establishing perfusion is not superior to conventional primary PCI in patients with STEMI.



Study Design

Patients presenting with STEMI and undergoing primary PCI with Thrombolysis in Myocardial Infarction (TIMI) 0-1 flow in the infarct-related artery were randomized in a 1:1 fashion to ischemic postconditioning (n = 617) or conventional PCI (n = 617). In the postconditioning group, immediately after restoration of coronary flow, an angioplasty balloon was positioned at the culprit lesion or stented segment and inflated 4 times for 30 seconds; each instance of inflation separated by 30 seconds of reflow.

  • Total number of enrollees: 1,214
  • Duration of follow-up: 37.5 months
  • Mean patient age: 62 years
  • Percentage female: 21%
  • Percentage diabetics: 9%

Other salient features/characteristics:

  • Infarct location: anterior (45%), inferior (52%)
  • Median stent number: 1; length: 23 mm
  • Drug-eluting stent use: 93%
  • Multivessel disease: 40%
  • Thrombus aspiration: 58%
  • Glycoprotein inhibitor use: 13%
  • Ticagrelor 40%, prasugrel 44%

Inclusion criteria:

  • STEMI presenting within 12 hours
  • TIMI 0-1 in infarct-related artery

Exclusion criteria:

  • Known intolerance of contrast media, anticoagulant, or dual antiplatelet therapy
  • Unconsciousness or cardiogenic shock
  • Stent thrombosis
  • Indication for acute coronary artery bypass grafting

Principal Findings:

The primary outcome, MACE (all-cause mortality, hospitalization for congestive heart failure [CHF]) for ischemic postconditioning vs. conventional PCI: 10.5% vs. 11.2%, hazard ratio 0.93, 95% confidence interval 0.66-1.30, p = 0.66

Components of the primary outcome:

  • All-cause mortality: 6.2% vs. 8.1%, p = 0.18
  • CHF hospitalization: 4.9% vs. 4.9%, p = 0.96

Secondary outcomes:

  • Recurrent MI: 5.4% vs. 4.7%, p = 0.64
  • Left ventricular ejection fraction (LVEF) at 18 months: 52.7% vs. 50.8%, p < 0.05
  • LVEF >45%: 80% vs. 72%, p = 0.015

Interpretation:

The results of this trial indicate that ischemic postconditioning (with short bursts of balloon occlusion immediately after establishing perfusion) is not superior to conventional primary PCI in patients with STEMI. There have been several smaller trials and one trial (POST) with 700 patients on postconditioning in patients presenting with STEMI with mixed results. This is the largest trial on this topic and demonstrates no difference between the two arms. The clinical utility of ischemic postconditioning during routine primary PCI is thus low. The method of inducing postconditioning has been different between the numerous studies, and the best protocol for this remains unclear. An improvement in LVEF at 18 months with ischemic postconditioning in this trial, but without a reduction in CHF hospitalizations, is puzzling, and can at best be considered hypothesis generating. The reasons behind this will need to be explored in future studies. 

References:

Presented by Dr. Thomas Engstrøm at the American College of Cardiology Annual Scientific Session, Chicago, IL, April 3, 2016.

Clinical Topics: Acute Coronary Syndromes, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Acute Heart Failure, Interventions and ACS

Keywords: Acute Coronary Syndrome, ACC Annual Scientific Session, Angioplasty, Balloon, Balloon Occlusion, Drug-Eluting Stents, Heart Failure, Ischemic Postconditioning, Myocardial Infarction, Percutaneous Coronary Intervention, Stents, Stroke Volume, Thrombosis


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