Amin AP, Spertus JA, Curtis JP, et al. - Using the Premier Healthcare Database, researchers analyzed trends and variations in Impella use, clinical outcomes, and expenses across US hospitals in patients receiving percutaneous coronary intervention (PCI) treated with mechanical circulatory support (MCS; Impella or intra-aortic balloon pump). This study included 48,306 patients undergoing PCI with MCS at 432 hospitals. Association analyses were performed at three levels—time period, hospital, and patient. For association analyses, hierarchical models with propensity adjustment were employed. Findings revealed a rapidly increasing use of Impella among patients receiving PCI treated with MCS. Experts reported a marked variability in its use and associated results. Analysis by time periods, or at the hospital level or the patient level, revealed higher rates of adverse events and expenses in correlation with Impella use. However, unmeasured confounding could not be ruled out.