Project Summary/Abstract Heart transplant (HT) is the option of last resort for many patients with advanced heart failure (HF). HF affected 5.7 million Americans in 2012. HF is known to be more common in black and Hispanic/Latino persons compared to their non-Hispanic white (NHW) counterparts. Extensive past evidence demonstrates racial/ethnic and socioeconomic disparities in healthcare access. In addition, there are well documented disparities in HT outcomes. While literature documenting disparities on the transplant waitlist and post-transplant exists, the path from advanced HF to transplant listing remains a ?black box?. This will be investigated through AIM 1: Evaluate the effects of race/ethnicity and SE status on the likelihood of referral for heart transplant evaluation, and how these effects vary geographically. Expected rates of HT listing will be modelled and compared to observed rates of listing stratified by race/ethnicity and socioeconomic status. Additionally, drivers of disparity in HT access are under-studied, especially with regard to patient- and transplant center-level variables that allow some patients a competitive advantage for HT. This will be investigated through AIM 2: Investigate geographic mobility and access to mechanical circulatory support (MCS) as drivers of disparities in access to transplantation. Transplant rates will be modelled with measures of geographic mobility as predictors. Drivers of geographic variation in MCS access and consequences of this variation for transplant access will also be investigated. Finally, in October 2018, the United Network for Organ Sharing allocation scheme was changed to further favor MCS as an indication for HT listing prioritization. The effects of this change on HT disparities will be investigated in AIM 3: Investigate the impact of the 2018 UNOS allocation scheme change on disparities in listing and transplantation with particular focus on the impact of access to MCS. Updated transplant rates including demographics will be obtained and will be evaluated for widening MCS access driven transplant disparities. This project will be conducted at Stanford University, an internationally renowned research institution with a reputation for cultivating young investigators. Additionally, Stanford is one of the most historic and rich environments in the world for HT research. It was the site of the first HT in the United States, remains a world leader in HT, and has esteemed faculty such as Dr. Jeffrey Teuteberg, President of the International Society of Heart and Lung Transplant. To complement this ideal environment, a training plan was developed focused on developing skills in biostatistics, health disparities and services research, geospatial analysis, and scientific communication, through coursework and frequent meetings with mentors whose expertise perfectly complement these goals.