Trends in mechanical support use as a bridge to adult heart transplant under new allocation rules

On October 18, 2018, new US adult heart transplant allocation rules were implemented by the Organ Procurement and Transplantation Network (OPTN). Updated rules were needed primarily to reduce significant overcrowding in the top-priority tier. A key modification divided the prior status 1A into 3 categories (status 1-3), reserving status 1 for the sickest few, and created status 4 corresponding to prior status 1B. In this division, patients supported by durable left ventricular assist devices (LVADs) were largely redistributed to lower tiers, reflecting improved waitlist survival with continuous-flow LVADs over the last decade. Patients with most LVAD complications or within the 30-day LVAD discretionary window, previously assigned status 1A, were made status 3. Remaining LVAD-supported patients became status 4 unless they have device malfunction (status 2) or life-threatening ventricular arrhythmias (status 1). Conversely, the smaller number of transplant candidates requiring veno-arterial extracorporeal membrane oxygenation (VA-ECMO), typically for biventricular failure, retain status 1 listing if stringent criteria are met justifying VA-ECMO. While the goal of these changes was to redistribute donor hearts to patients at higher risk of pretransplant mortality, the degree to which this has affected VA-ECMO or LVAD use as a bridge to transplantation is unknown.

National Heart, Lung, and Blood Institute ( NHLBI)