The Evolving Landscape of Impella Use in the United States among Patients Undergoing Percutaneous Coronary Intervention with Mechanical Circulatory Support

Background: Impella was approved for mechanical circulatory support (MCS) in 2008, but large-scale, real-world data on its use are lacking. Our objective was to describe trends and variations in Impella use, clinical outcomes, and costs across US hospitals in patients undergoing percutaneous coronary intervention (PCI) treated with MCS (Impella or intra-aortic balloon pump). Methods: From the Premier Healthcare Database, we analyzed 48 306 patients undergoing PCI with MCS at 432 hospitals between January 2004 and December 2016. Association analyses were performed at 3 levels: time period, hospital, and patient. Hierarchical models with propensity adjustment were used for association analyses. We examined trends and variations in the proportion of Impella use, and associated clinical outcomes (in-hospital mortality, bleeding requiring transfusion, acute kidney injury, stroke, length of stay, and hospital costs). Results: Among patients undergoing PCI treated with MCS, 4782 (9.9%) received Impella; its use increased over time, reaching 31.9% of MCS in 2016. There was wide variation in Impella use across hospitals (>5-fold variation). Specifically, among patients receiving Impella, there was a wide variation in outcomes of bleeding (>2.5-fold variation), and death, acute kidney injury, and stroke (all ≈1.5-fold variation). Adverse outcomes and costs were higher in the Impella era (years 2008-2016) versus the pre-Impella era (years 2004-2007). Hospitals with higher Impella use had higher rates of adverse outcomes and costs. After adjustment for the propensity score, and accounting for clustering of patients by hospitals, Impella use was associated with death: odds ratio, 1.24 (95% CI, 1.13-1.36); bleeding: odds ratio, 1.10 (95% CI, 1.00-1.21); and stroke: odds ratio, 1.34 (95% CI, 1.18-1.53), although a similar, nonsignificant result was observed for acute kidney injury: odds ratio, 1.08 (95% CI, 1.00-1.17). Conclusions: Impella use is rapidly increasing among patients undergoing PCI treated with MCS, with marked variability in its use and associated outcomes. Although unmeasured confounding cannot be ruled out, when analyzed by time periods, or at the hospital level or the patient level, Impella use was associated with higher rates of adverse events and costs. More data are needed to define the appropriate role of MCS in patients undergoing PCI.