An Assessment of Patient Selection for Impella Device Implantation in Cardiogenic Shock

Abstract

Introduction In patients with refractory heart failure, there is increasing interest in the use of temporary mechanical circulatory support devices as a bridge to recovery or advanced cardiac therapies. One such family of devices, Impella (ABIOMED), is approved for use in acute myocardial infarction complicated by cardiogenic shock (AMI-CS), but has seen increased use in non-AMI-CS. The goal of this study was to better characterize patient selection for device implantation and outcomes among a contemporary cohort of patients supported with Impella for cardiogenic shock. Methods We collected data on all patients with these devices in the cardiovascular intensive care unit (CVICU) at Vanderbilt University Medical Center between November 1st, 2018 and December 31st, 2019. Patients already on extracorporeal membrane oxygenation with subsequent Impella placement for left ventricular unloading and those solely undergoing an Impella-supported procedure were excluded. Results See Table 1 for full demographics. Twenty-four (63.2%) patients had an indwelling pulmonary artery catheter (PAC) at or prior to Impella insertion. Overall survival to discharge for the cohort was 44.7%. According to the Society of Coronary Angiography and Interventions (SCAI) cardiogenic shock classification at the time of CVICU admission, 55.6% in SCAI stage C, 53.3% in SCAI stage D, and 30.8% in SCAI stage E survived to discharge. Five of twenty-one patients (23.8%) who did not survive to discharge died within 12 hours of implantation due to refractory cardiogenic shock or cardiac arrest; three of these (60%) were in Stage E shock at the time of CVICU admission. Conclusions These data suggest heterogenous selection of patients for implantation of Impella devices for cardiogenic shock. In particular, it is of concern that fewer than two-thirds of patients referred had hemodynamic monitoring with PAC prior to or at the time of device implantation, as recent studies have suggested a mortality benefit with the early use of PACs in the diagnosis and management of cardiogenic shock. The early use of PACs may help appropriately select candidates for not just mechanical support, but the right type of support. This retrospective review of our data is not powered to detect statistically significant differences. However, it helps guide understanding of clinical problems that need additional data and randomized studies to improve outcomes. Even the best medical devices, when deployed in the wrong patient, at the wrong time, or for the wrong reason are likely to yield poor outcomes.