Counterpulsation to Reduce Infarct Size Pre-PCI Acute Myocardial Infarction - CRISP AMI
Patients presenting with anterior ST-segment elevation myocardial infarction (STEMI) are at high risk for adverse outcomes, despite undergoing primary percutaneous coronary intervention (PPCI). Intra-aortic balloon pump (IABP) is frequently employed in patients with STEMI who either present or tend towards cardiogenic shock. The current trial sought to study if routine IABP use in patients with anterior STEMI who were not in cardiogenic shock would result in reduced infarct size and improved clinical outcomes.
Routine IABP use in patients with anterior STEMI not in cardiogenic shock would be associated with a reduction in infarct size, as assessed by cardiac magnetic resonance imaging (CMR) 3-5 days following PCI.
- Anterior STEMI
- 2 mm in two contiguous leads or at least 4 mm in the anterior leads
- Planned PPCI within 6 hours
- Adult able to consent
Number of enrollees: 337
Duration of follow-up: 6 months
Mean patient age: 56.6 years (median)
Percentage female: 18%
- Known contraindication to CMR
- Prior thrombolytic therapy for STEMI
- Cardiogenic shock
- Prior MI, coronary artery bypass grafting, or end-stage renal disease
- Contraindications to IABC
- Known severe aortic insufficiency, abdominal aortic aneurysm, or severe peripheral artery disease
- >400 lbs or <4 feet tall
- Infarct size, as determined by CMR at 3-5 days post-PCI
- Vascular complications
- Major bleeding
All patients meeting inclusion criteria were randomized to either IABP use prior to PCI, or standard of care PPCI, with IABP use as “bailout” if necessary.
Unfractionated heparin (79%), glycoprotein IIb/IIIa inhibitor (47%), bivalirudin (16%). On discharge: aspirin (98%), clopidogrel (76%), prasugrel (20%), statins (96%).
A total of 337 patients were randomized, 161 to IABP prior to PCI and 176 to standard PCI. Baseline characteristics were fairly similar between the two arms. A total of 15 patients crossed over from standard PCI to IABP, mainly due to development of sustained hypotension or cardiogenic shock. About 48% of the patients were Caucasian, and 45% Asian. About 19% had a history of diabetes mellitus, 29% hypertension, and 32% were current nicotine users. The median systolic blood pressure/diastolic blood pressure on admission was 131/80 mm Hg, with a median heart rate of 75 bpm. The majority of patients had ≥6 mm ST elevation in the anterior leads. PCI was successfully performed in 94% of the patients, and the left anterior descending artery (LAD) was the target vessel in 97.6% of the patients. A proximal LAD lesion was noted in 63% of the patients. About 65% of the patients had Thrombolysis In Myocardial Infarction (TIMI) 0 flow at baseline, and 94% had TIMI 3 flow at the end of the procedure. The median door-to-first device insertion time was slightly higher in the IABP arm (77 vs. 68 min, p = 0.04). Aspiration thrombectomy was performed in about 35% of the patients. Bare-metal stents were used in 53.4% of patients. IABP was continued for >24 hours in all patients, and the median duration of IABP use was 22.1 hours.
The primary endpoint of mean infarct size on cardiac magnetic resonance was similar between the IABP and standard PCI arms (42.1 vs. 37.5, p = 0.06). Clinical events at 30 days were similar, including all-cause mortality (1.9% vs. 4.0%, p = 0.26), stroke (1.9% vs. 0.6%, p = 0.35), and major bleeding per Global Use of Strategies to Open Coronary Arteries (GUSTO) definition (3.1% vs. 1.7%, p = 0.49); vascular complications were numerically higher in the IABP arm (4.3% vs. 1.1%, p = 0.09). Similarly, at 6 months, clinical outcomes were comparable, including all-cause mortality (1.9% vs. 5.2%, p = 0.12), and death/MI/congestive heart failure (CHF) (6.3% vs. 10.9%, p = 0.15). A significant reduction in the composite endpoint of death/shock/CHF was noted in the IABP arm (5% vs. 12%, p = 0.03).
The results of the current trial indicate that routine IABP use before PCI in patients with anterior STEMI who are not in cardiogenic shock is not associated with a reduction in infarct size or improved clinical outcomes at 6 months, as compared with standard of care PCI, with IABP use reserved as “bailout” for cardiogenic shock/unsuccessful PCI. However, IABP requirement is relatively common in these patients, with a crossover rate of about 8-9% observed in this trial. Further long-term data are awaited. These results are similar to those noted in the BCIS-1 trial in patients undergoing high-risk PCI.
Patel MR, Smalling RW, Thiele H, et al. Intra-aortic balloon counterpulsation and infarct size in patients with acute anterior myocardial infarction without shock: the CRISP AMI randomized trial. JAMA 2011;Aug 29:[Epub ahead of print].
Presented by Dr. Manesh Patel at the European Society of Cardiology Congress, Paris, France, August 2011.
Clinical Topics: Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Prevention, Aortic Surgery, Cardiac Surgery and Heart Failure, Acute Heart Failure, Mechanical Circulatory Support, Interventions and Imaging, Magnetic Resonance Imaging, Hypertension
Keywords: Myocardial Infarction, Nicotine, Stroke, Follow-Up Studies, Standard of Care, Hypotension, Heart Rate, Magnetic Resonance Imaging, Stents, Percutaneous Coronary Intervention, Shock, Cardiogenic, Metals, Thrombectomy, Heart Failure, Intra-Aortic Balloon Pumping, Coronary Vessels, Magnetic Resonance Spectroscopy, Hypertension, Diabetes Mellitus
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