Impella Pump for MI Shock Again Fares Poorly vs IABP in Study


Another observational study questioned whether Impella (Abiomed) assisted ventricular pumps should be used in patients with acute myocardial infarction (MI) complicated by cardiogenic shock (CS), at least compared to an intra-aortic balloon pump (IABP) , the most common alternative.

Treatment with the Impella device, compared with IABP support, was associated with an increased risk of bleeding complications, kidney injury, and death, both short-term and within 1 year, according to a new analysis of US data on the requirements of such patients undergoing percutaneous coronary anesthesia with support. intervention (PCI).

Overall healthcare costs during hospitalization were also significantly higher with the Impella, which is often described in the literature as an intravascular left ventricular microaxial assist device (LVAD).


The clinical results in the analysis are largely consistent with previous observational studies and other data indicating a similar relative harm from Impella during hospitalization of patients with acute MI and CS. But the current analysis adds by assuming such results extend over 1 year.

While such results may conceivably vary across some subsets of patients, “there is currently insufficient data to conclusively say whether there is a particular patient phenotype that would benefit more from a particular device,” said P. Elliott Miller, MD, PhD. MHS, Yale University. School of Medicine, New Haven, Connecticut, who is the lead author of the analysis published July 18 in JAMA Internal Medicine.

Current findings, he told | Medscape Cardiology, “are consistent with several other observational studies and should be taken into account when guidelines authors make recommendations.” But a randomized trial is needed to clarify these issues, he added, noting that the report concludes that “there is an urgent need for appropriately powered randomized clinical trials to better inform clinical decisions in this critically ill patient population.”


In hospital, 30 days and 1 year

The panel reviewed claims data from 3,077 patients, about 28% of whom were women, who underwent PCI for acute MI with CS from 2015 to 2020. using the Impella or IABA device.

The odds ratio (OR) or risk ratio (HR) for mortality for those receiving Impella, compared with IABP, were:

  • OR, 1.63 (95% CI, 1.32–2.02) in hospital

  • OR, 1.71 (95% CI, 1.37–2.13) at 30 days

  • HR, 1.44 (95% CI, 1.21–1.71) at 1 year

Other 30 day results for Impella vs IABP included:

  • OR 1.35 (95% CI, 1.04–1.76) for bleeding

  • OR, 1.88 (95% CI, 1.30–2.73) for renal replacement therapy

  • + $51,680 for average total healthcare costs

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Relevant results at 1 year for Impella compared to IABP:

  • HR, 1.36 (95% CI, 1.05–1.75) for bleeding

  • HR, 1.95 (95% CI, 1.35-2.83) for renal replacement therapy

  • + $46,609 for average total healthcare costs

The results were similar across various sensitivity analyses, including one that involved the entire cohort of 3,077 patients from which matching propensity pairs were drawn, adjusted for propensity matching criteria, the group reports.


“This is a retrospective observational study with a very significant potential for bias,” Riyaz Bashir, MD, Temple University, and director of the Department of Vascular and Endovascular Medicine, Temple University Hospital of Philadelphia, told | Medscape Cardiology. “The study is very good, but it forms hypotheses and should not change the guidelines.”

Bashir, not involved in the analysis, agreed on the need for large randomized controlled trials to determine the best MCS strategy. He said that microaxial LVAD is likely to be preferred over IABP for the subgroup of patients with acute MI with CS who are “so ill that the additional 0.5 liters of cardiac output increase provided by IABP is not enough. You want to be able to get through the case and finish the patient’s treatment. And this will be the time when LVAD should be the first implanted device.”

The accompanying editorial highlights the need for reforms in the US Food and Drug Administration’s approval processes and post-market surveillance processes for invasive devices used to treat acute MI with CS, as well as more robust surveillance. But he also advocates ending the use of the microaxial left ventricle in clinical practice.


“Until such reforms are implemented, and given the prevalence of existing evidence, the use of intravascular microaxial LVAD in individuals with myocardial infarction with cardiogenic shock should be limited to patients enrolled in [a randomized controlled trial]write the authors of the editorial, led by Jin Hu, MD, Anand R. Habib, MD, M.Phil., and Rita F. Redberg, MD, M.Sc., all from the University of California, San Francisco. Hu is the Editorial Fellow. and Redberg, editor of JAMA Internal Medicine.

But Timothy Henry, MD, comments on the study for | Medscape Cardiology pointed to the position taken in last year’s American Heart Association (AHA) scientific statement on the invasive treatment of acute MI complicated by CS, of which he was the lead author.

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The statement acknowledges studies published in the literature supporting Impella-supported PCI for MI with CS, as well as studies suggesting harm, and states that such studies should “inform the management” of such patients. Meanwhile, he continues, “there are grounds for caution as observational evidence illustrates the heterogeneity of safety and outcomes in the use of MCS in the context of steadily growing use.”

Thus, Henry said, it is important to tailor MCS use and device choice to individual patients with acute MI complicated by CS. The scientific statement says that such personalized care takes into account “the underlying mechanisms of shock, the anticipated benefits and risks of MCS, and the ideal timing for device insertion.”

Similar positions were set out in an AHA policy statement, also released in 2021, which lists Henry as one of the sponsors. It states that the Impella, IABP and other MCS devices should be made available for the treatment of patients with acute MI and CS in experienced centers. “However, it should be noted that there are no robust data from adequately powered randomized trials evaluating the risks and benefits of mechanical circulatory support.”

Therefore, the statement says, together with lead author Alice C. Jacobs, MD, Boston University and Boston Medical Center, Massachusetts, recommends a personalized approach to care with early mechanical support prior to PCI for patients with refractory hemodynamic instability despite aggressive drug therapy. “For those who develop or develop CS in the hospital, it is said that “treatment with advanced mechanical circulatory support devices should be started early.”

Miller reported no conflicts; disclosures to other authors are contained in the report. Henry did not disclose information in the AHA’s scientific statement. Bashir reportedly did not disclose the information.

JAMA Intern Med. Posted online July 18, 2022 Editorial Abstract

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