The evolving role of percutaneous ventricular assist devices in high-risk cardiac patients

The Impella is a mechanical circulatory support device that supports ventricular function. Since 2008, when the first Impella device received Food and Drug Administration clearance, its use has become increasingly prevalent. A variety of Impella devices are available, and are differentiated by size, power, and insertion techniques. These versions of the Impella have been used in a multitude of clinical scenarios, both emergent and elective, including high-risk coronary interventions, acute myocardial infarction complicated by cardiogenic shock, decompensated left and right heart failure, high-risk ventricular tachycardia ablations, and aortic valvuloplasty. However, the available evidence supporting its use is less than robust, primarily consisting of case reports and registries, with a limited number of randomized-controlled trials comparing the Impella with the intra-aortic balloon pump. Although these trials show that the Impella provides better hemodynamic support compared with the intra-aortic balloon pump, they failed to show a survival benefit for the Impella. This finding may have a number of explanations, foremost the inherent difficulty of selecting appropriate patients for trials that are conducted in extreme clinical settings. In this study, we discuss the mechanism of the Impella and the different types of Impella devices available, and review the medical literature for evidence of its efficacy in treating cardiac patients. Although the Impella has become ubiquitous in certain markets, such as in the USA, it has yet to be a part of the standard of care for patients in Israel.