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  • IABP-SHOCK II Original

    • IABP-SHOCK II

    "Intraaortic Balloon Counterpulsation in Acute Myocardial Infarction-Complicated Cardiogenic Shock"

    1. **Clinical Question**
    - Does intraaortic balloon counterpulsation reduce 30-day mortality in patients with acute myocardial infarction-complicated cardiogenic shock who are undergoing early revascularization?

    2. **Bottom Line**
    - In patients with cardiogenic shock complicating acute myocardial infarction who were planned for early revascularization, intraaortic balloon counterpulsation did not significantly reduce 30-day all-cause mortality compared to conventional therapy alone.

    3. **Major Points**
    - Though listed as a Class I treatment in international guidelines for cardiogenic shock complicating acute myocardial infarction, existing evidence supporting intraaortic balloon counterpulsation primarily comes from registry data, with a lack of robust randomized clinical trials.


    4. **Guidelines**
    - Prior to this study, intraaortic balloon counterpulsation was recommended as Class IB and IC treatment by U.S. and European guidelines, respectively, for cardiogenic shock following acute myocardial infarction.

    5. **Design**
    - Multicenter, open-label, randomized controlled trial with a total of 600 participants.
    - Interventions: Intraaortic balloon counterpulsation vs. no intraaortic balloon counterpulsation.

    6. **Population**
    - Inclusion Criteria: Patients presenting with acute myocardial infarction (with or without ST-segment elevation) complicated by cardiogenic shock and planned for early revascularization (PCI or CABG).
    - Exclusion Criteria: Extensive list includes prolonged resuscitation, absent heart action, severe concomitant diseases, and mechanical causes of cardiogenic shock.

    7. **Interventions**
    - Patients were randomized to intraaortic balloon counterpulsation (IABP group - 301 patients) or a control group without intraaortic balloon counterpulsation (control group - 299 patients).

    8. **Outcomes**
    - Primary Outcome: 30-day all-cause mortality. No significant difference between the groups was observed (IABP group 39.7% vs. control group 41.3% with a relative risk of 0.96).
    - Secondary Outcomes: No significant differences in secondary clinical endpoints or process-of-care measures including time to hemodynamic stabilization, ICU stay length, lactate levels, catecholamine therapy, renal function, and others.

    9. **Criticisms**
    - Lack of blinding due to nature of the intervention.
    - Absence of detailed hemodynamic measurements.
    - Not all patients with severe cardiogenic shock were included, raising questions about the generalizability of the study findings to this subset of patients.

    10. **Funding**
    - Funded by the German Research Foundation and others, with unrestricted grants from Maquet Cardiopulmonary and Teleflex Medical.

    11. **Further Reading**
    - New England Journal of Medicine article: "Intraaortic Balloon Counterpulsation in Cardiogenic Shock Complicating Acute Myocardial Infarction" and clinical trial registration number NCT00491036.

    ClinicalTrials.gov number, NCT00491036.