Amin Analysis: Review of Trends, Variation and Outcomes in Impella® Use

Seth Bilazarian, MD, provides a review of the observational analysis published in Circulation and presented at AHA 2019 by Amin, et al., comparing the Impella® heart pump to the intra-aortic balloon pump (IABP).

Dr. Bilazarian notes that the study is an observational, non-FDA audited analysis that is fundamentally flawed because it is based on poor quality, retrospective, payer coding data. He also explains that the data lumps all indications together – including elective and urgent cases – making it impossible to properly propensity match. “In this data set, a patient arriving for an elective procedure is included in the same data set as a patient in cardiac arrest with cardiogenic shock,” says Dr. Bilazarian.

According to Dr. Bilazarian, in the data set the authors selected, Impella patients are much sicker and have greater baseline and procedural risks, including higher rates of multivessel disease, diabetes and chronic renal failure. With those flaws, Dr. Bilazarian says it’s not surprising that the authors’ opinions conflict with the conclusions of more robust, previously published, FDA-audited, prospective real-world studies and randomized controlled trials.

Dr. Bilazarian notes that multiple peer-reviewed studies, including the PROTECT II randomized controlled trial, demonstrate Impella improves survival in cardiogenic shock and reduces death, stroke, MI and repeat revascularization in high-risk PCI. Robust studies also demonstrate Impella enables more complete revascularization and improves ejection fraction and patient quality of life at 90 days. Notably, says Dr. Bilazarian, data from the PROTECT series, which compares truly similar Impella and IABP patients, shows that patients treated with Impella had numerically lower rates of vascular complications compared with patients treated with IABP.

Finally, Dr. Bilazarian says that the observational analysis by Amin, et al., fails to reference multiple publications demonstrating the cost-effectiveness of Impella. This includes the 2014 Yale paper by Stretch, et al., that examined data from the National Inpatient Sample (NIS) and found PVADs reduced costs and reduced mortality by 58%. Dr. Bilazarian also notes that the Amin analysis removed patients who were escalated to other therapies, which is the major driver of costs and poor outcomes for IABP.