Intra-Aortic Balloon Counterpulsation and Infarct Size in Patients With Acute Anterior Myocardial Infarction Without Shock: The CRISP AMI Randomized Trial

OBJECTIVES: Intra-aortic balloon counterpulsation (IABC) is an adjunct to revascularization in patients with cardiogenic shock and reduces infarct size when placed prior to reperfusion in animal models.To determine if routine IABC placement prior to reperfusion in patients with anterior ST-segment elevation myocardial infarction (STEMI) without shock reduces myocardial infarct size.

METHODS: An open, multicenter, randomized controlled trial, the Counterpulsation to Reduce Infarct Size Pre-PCI Acute Myocardial Infarction (CRISP AMI) included 337 patients with acute anterior STEMI but without cardiogenic shock at 30 sites in 9 countries from June 2009 through February 2011.Intervention Initiation of IABC before primary percutaneous coronary intervention (PCI) and continuation for at least 12 hours (IABC plus PCI) vs primary PCI alone.Main Outcome Measures Infarct size expressed as a percentage of left ventricular (LV) mass and measured by cardiac magnetic resonance imaging performed 3 to 5 days after PCI. Secondary end points included all-cause death at 6 months and vascular complications and major bleeding at 30 days. Multiple imputations were performed for missing infarct size data.

RESULTS: The median time from first contact to first coronary device was 77 minutes (interquartile range, 53 to 114 minutes) for the IABC plus PCI group vs 68 minutes (interquartile range, 40 to 100 minutes) for the PCI alone group (P = .04). The mean infarct size was not significantly different between the patients in the IABC plus PCI group and in the PCI alone group (42.1% [95% CI, 38.7% to 45.6%] vs 37.5% [95% CI, 34.3% to 40.8%], respectively; difference of 4.6% [95% CI, -0.2% to 9.4%], P = .06; imputed difference of 4.5% [95% CI, -0.3% to 9.3%], P = .07) and in patients with proximal left anterior descending Thrombolysis in Myocardial Infarction flow scores of 0 or 1 (46.7% [95% CI, 42.8% to 50.6%] vs 42.3% [95% CI, 38.6% to 45.9%], respectively; difference of 4.4% [95% CI, -1.0% to 9.7%], P = .11; imputed difference of 4.8% [95% CI, -0.6% to 10.1%], P = .08). At 30 days, there were no significant differences between the IABC plus PCI group and the PCI alone group for major vascular complications (n = 7 [4.3%; 95% CI, 1.8% to 8.8%] vs n = 2 [1.1%; 95% CI, 0.1% to 4.0%], respectively; P = .09) and major bleeding or transfusions (n = 5 [3.1%; 95% CI, 1.0% to 7.1%] vs n = 3 [1.7%; 95% CI, 0.4% to 4.9%]; P = .49). By 6 months, 3 patients (1.9%; 95% CI, 0.6% to 5.7%) in the IABC plus PCI group and 9 patients (5.2%; 95% CI, 2.7% to 9.7%) in the PCI alone group had died (P = .12).

CONCLUSIONS: Among patients with acute anterior STEMI without shock, IABC plus primary PCI compared with PCI alone did not result in reduced infarct size. Alex Cappa Jersey

PMID: 21878431

Posted in * Journal Club Selections, Invasive Imaging, Magnetic Resonance Imaging and tagged , , , , , , , .

One Comment

  1. Intra-aortic Balloon Counterpulsation and Infarct Size in Patients With Acute Anterior Myocardial Infarction Without Shock

    1. What are the hemodynamic changes that are induce by IABC? and how could these changes benefit stable patients with anterior myocardial infarction? (Hypothetical benefit)
    Intra-aortic balloon contrapulsation mechanically augments coronary blood flow, decreases afterload unloading the LV reducing the myocardial oxygen demand.
    Any patient with an anterior acute coronary syndrome hypothetically should benefit from reducing the LV afterload, improving coronary perfusion and reducing O2 demand.

    2. Is there any evidence ( animal models/humans) that could suggest a benefit of IABC insertion prior PCI for stable patients with an anterior STEMI.
    Prior animal studies by Anchour et all & haendchen et al show decrease LV infarct after LV unloading therapies in a canine model.
    In humans 5 previous randomized trials have assessed the role of IABC in patients with AMI without cardiogenic shock. However, neither these trials nor the CRISP AMI trial were sufficiently powered for the evaluation of clinical out- comes with IABC, with only 21 deaths among 518 patients in the IABC groups and 21 deaths among 536 patients in the control groups across the studies.
    – 0. Flaherty JT, Becker LC, Weiss JL, et al. Results of a randomized prospective trial of intraaortic balloon counterpulsation and intravenous nitroglycerin in-patients with acute myocardial infarction. J Am Coll Cardiol. 1985;6(2):434- 446.
    – Kono T, Morita H, Nishina T, et al. Aortic counterpulsation may improve late patency of the occluded coronary artery in patients with early failure of throm- bolytic therapy. J Am Coll Cardiol. 1996;28(4):876-881. Ohman EM, George BS, White CJ, et al; Randomized IABP Study Group. Use of aortic counterpulsation to improve sustained coronary artery patency during acute myocardial infarction. Circulation. 1994;90(2):792-799.
    – Stone GW,MarsaleseD,BrodieBR,etal;SecondPrimaryAngioplastyinMyo- cardial Infarction (PAMI-II) Trial Investigators. A prospective, randomized evalu- ation of prophylactic intraaortic balloon counterpulsation in high risk patients with acute myocardial infarction treated with primary angioplasty. J Am Coll Cardiol. 1997;29(7):1459-1467.
    – Vijayalakshmi K, Kunadian B, Whittaker VJ, et al. Intra-aortic counterpulsa- tion does not improve coronary flow early after PCI in a high-risk group of patients. J Invasive Cardiol. 2007;19(8):339-346.

    3. What is the aim of the study? 4. What were the end-points defined for the study. What other end-points could have been analyzed?
    To determine if IACP prior PCI (standard of care) reduces infarct size in anterior ACS. The authors also investigate clinical end point such as all cause mortality, repeat reinfarction and heart failure admissions.

    5. How was the randomization done?
    Randomization was done following 24 hour voice response computed generated algorithm that took in account patient characteristics and location.

    6. Do you think the infarct assess by EKG is an optimal screening tool for selecting patients for this trial ?
    It is not the most optimal screening toll but is probable the most practical since it is a fast, cheap, and widely available and will not delay the final therapy initiation

    7. Do you think any other clinical or laboratory markers could be added to electrocardiographic MI size to better identify patient with worst outcomes or that could benefit from IABC ?
    In the future initial levels of BNP, cardiac biomarkers such as troponins & CRP or killip classification could help in the reclassification of this patient into a IABP prior reperfusion vs reperfusion alone

    8. Does this study suggest the need for further research . What changes would you suggest for the methodology?
    Yes, especially in studies power to identify differences in clinical events. Also different window times with shorter reperfusion times > 6 hours before the onset of the symptoms. Also MRI could be performed a month after ACS and compared to the one obtained 3-5 days post reperfusion.

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