Association of Use of an Intravascular Microaxial Left Ventricular Assist Device vs Intra-aortic Balloon Pump With In-Hospital Mortality and Major Bleeding Among Patients With Acute Myocardial Infarction Complicated by Cardiogenic Shock

Importance Acute myocardial infarction (AMI) complicated by cardiogenic shock is associated with substantial morbidity and mortality. Although intravascular microaxial left ventricular assist devices (LVADs) provide greater hemodynamic support as compared with intra-aortic balloon pumps (IABPs), little is known about clinical outcomes associated with intravascular microaxial LVAD use in clinical practice. Objective To examine outcomes among patients undergoing percutaneous coronary intervention (PCI) for AMI complicated by cardiogenic shock treated with mechanical circulatory support (MCS) devices. Design, Setting, and Participants A propensity-matched registry-based retrospective cohort study of patients with AMI complicated by cardiogenic shock undergoing PCI between October 1, 2015, and December 31, 2017, who were included in data from hospitals participating in the CathPCI and the Chest Pain-MI registries, both part of the American College of Cardiology's National Cardiovascular Data Registry. Patients receiving an intravascular microaxial LVAD were matched with those receiving IABP on demographics, clinical history, presentation, infarct location, coronary anatomy, and clinical laboratory data, with final follow-up through December 31, 2017. Exposures Hemodynamic support, categorized as intravascular microaxial LVAD use only, IABP only, other (such as use of a percutaneous extracorporeal ventricular assist system, extracorporeal membrane oxygenation, or a combination of MCS device use), or medical therapy only. Main Outcomes and Measures The primary outcomes were in-hospital mortality and in-hospital major bleeding. Results Among 28304 patients undergoing PCI for AMI complicated by cardiogenic shock, the mean (SD) age was 65.0 (12.6) years, 67.0% were men, 81.3% had an ST-elevation myocardial infarction, and 43.3% had cardiac arrest. Over the study period among patients with AMI, an intravascular microaxial LVAD was used in 6.2% of patients, and IABP was used in 29.9%. Among 1680 propensity-matched pairs, there was a significantly higher risk of in-hospital death associated with use of an intravascular microaxial LVAD (45.0%) vs with an IABP (34.1% [absolute risk difference, 10.9 percentage points {95% CI, 7.6-14.2}; P < .001) and also higher risk of in-hospital major bleeding (intravascular microaxial LVAD [31.3%] vs IABP [16.0%]; absolute risk difference, 15.4 percentage points [95% CI, 12.5-18.2]; P < .001). These associations were consistent regardless of whether patients received a device before or after initiation of PCI. Conclusions and Relevance Among patients undergoing PCI for AMI complicated by cardiogenic shock from 2015 to 2017, use of an intravascular microaxial LVAD compared with IABP was associated with higher adjusted risk of in-hospital death and major bleeding complications, although study interpretation is limited by the observational design. Further research may be needed to understand optimal device choice for these patients. This study uses registry data to compare risk of in-hospital mortality and major bleeding among patients with acute coronary syndrome and cardiogenic shock managed with an intravascular microaxial left ventricular assist device (LVAD) vs intra-aortic balloon pulsation (IABP). Question Is there a difference in clinical outcomes among patients with acute myocardial infarction (AMI) complicated by cardiogenic shock treated with intravascular microaxial left ventricular assist device (LVAD) vs intra-aortic balloon pump (IABP)? Findings In this registry-based retrospective cohort study that included 3360 propensity-matched patients undergoing percutaneous coronary intervention for AMI, treatment with intravascular microaxial LVAD vs IABP was associated with a significantly higher risk of in-hospital death (45.0% vs 34.1%) and in-hospital major bleeding (31.3% vs 16.0%). Meaning The use of intravascular microaxial LVAD compared with IABP may be associated with worse in-hospital clinical outcomes among patients with AMI and cardiogenic shock undergoing percutaneous coronary intervention, although study interpretation is limited by the observational design.