Trends in Mechanical Circulatory Support utilization, Left Ventricular Assist Device implantation and Transplant during Cardiogenic Shock Hospitalizations, after the New Heart Allocation Policy

Background In October 2018, a new heart allocation policy was implemented to risk stratify patients listed for transplant, prioritizing patients supported with temporary mechanical circulatory support (MCS). The policy changes may have had an impact on the management of cardiogenic shock (CS). We sought to determine the changes in use of temporary MCS, durable left ventricular assist device (LVAD) and transplant in patients hospitalized before and after the new policy. Methods A retrospective analysis was conducted using the National Inpatient Sample (NIS) between 2017– 2020. Hospitalizations for cardiogenic shock were identified, and stratified based on whether patients were admitted before or after the policy change. Baseline characteristics were compared between cohorts, and the primary outcome of interest was the use of MCS, transplant and LVAD before and after the policy change. Subgroup analyses included patients hospitalized at transplant and non-transplant centers, LVAD recipients as well as those who underwent transplant. Results A total of 643,655 hospitalizations were included, of which 260,340 (40.4%) were before the policy change, and 383,315 (59.6%) were after. In all patients with CS, there was a decrease in the use of LVAD (adjusted OR 0.73, p<0.01) and an increase in cardiac transplant (adjusted OR 1.45, p<0.01). While IABP use declined for the general CS population (adjusted OR 0.81, p<0.01), it increased significantly in cardiac transplant recipients (adjusted OR 2.55; p<0.01). Impella and VA-ECMO also increased in transplant recipients. No uptrend was seen in any other subgroup including LVAD recipients or CS patients managed in transplant centers. Conclusion Our study showed that the allocation policy change had a direct impact on MCS use in the first two years after implementation, but this effect was isolated to patients who underwent transplantation. It will be important to study how policy changes influence the management of other shock populations over time.