Impending savior: Impella 2.5 circulatory support system in high‐risk PCI

Patients with high-risk complex coronary lesions including 3-vessel disease, unprotected left main disease or a single remaining patent vessel along with depressed left ventricular (LV) function have limited therapeutic options due to excessive comorbidities and worse prognosis than the general percutaneous coronary intervention (PCI) population. The recommended revascularization strategy for this high-risk population with symptoms of angina and heart failure is coronary artery bypass grafting [1], but high procedural mortality and morbidity often precludes major surgery. Conversely, advances in PCI technique, procedural refinements, and novel adjunctive pharmacology have expanded the therapeutic possibilities over the past decade. High-risk PCI has been offered to these highrisk patients as a rescue procedure, but there are circumstances when transient interruptions of coronary blood flow might result in hemodynamic compromise or collapse leading to worse outcomes. Thus, percutaneous circulatory assist devices have emerged as attractive adjuncts in the high-risk population. Currently, the intra-aortic balloon pump (IABP) is the most commonly used device (an estimated 30% in United States) for circulatory support but it has limited efficacy in patients with depressed LV function and is associated with many complications. Moreover, standard of care of IABP and current guidelines have recently been challenged by a Balloon Pump Accessed Coronary Intervention Study randomized controlled trial, which showed that the elective use of IABP in this population did not alter either the primary end point of major adverse cardiovascular and cerebrovascular events (14.6% vs. 15.3%; P 5 0.35) or the major secondary end point of 6-month mortality (4.6% vs 7.3%; P 5 0.32) as compared to conventional PCI [2]. A newer available option that has recently been shown to provide superior hemodynamic support compared to the IABP is Impella 2.5. Since its introduction in Europe in 2004, Impella 2.5 has been used in a wide range of clinical settings including high risk PCI. As per the observational registry, it has been shown that patient outcomes are better with prophylactic use of LV assist device compared to in patients with cardiogenic shock [3]. A number of previous studies such as the PROTECT I (Prospective Feasibility Trial Investigating the Use of the Impella 2.5 System in Patients Undergoing High-Risk PCI) trial, the Europella registry and the registry by Henriques et al. have shown that periprocedural circulatory support with Impella 2.5 for elective high-risk PCI is both safe and feasible. The Europella data registry (a multicenter study with n 5 144 high risk patients) showed low adverse event rates, with myocardial infarction, stroke, bleeding requiring transfusion or surgery, and vascular complications at 30 days were 0, 0.7, 6.2, and 4.0%, respectively, and 30-day mortality was 5.5%. Henriques et al. have provided further encouraging results regarding the periprocedural use of Impella 2.5. In their series of 19 highrisk patients, there was no device related adverse events, aortic valve damage or procedural death. An early US experience from the PROTECT I trial of 20 high-risk patients, has shown a 20% incidence of MACE at 30 days and no evidence of aortic valve injury, cardiac perforation or limb ischemia, without any patient developing hemodynamic compromise [4]. The PROTECT II trial was the first randomized controlled trial in United States of the Impella 2.5 System versus IABP in patients undergoing nonemergent highrisk PCI. Although the intention-to-treat analysis demonstrated no difference between treatment groups, the per-protocol analysis (n 5 426) showed that the Impella was associated with 21% fewer major adverse events at 90 days than IABP (40.8% vs. 51.4%; P 5 0.029). The clinical benefit was more pronounced in patients undergoing high-risk PCI without rotational atherectomy with the Impella support. Impella significantly reduced out-of-hospital major adverse events