Impact of Mechanical Circulatory Support and Heart Transplantation on Survival of the Population of Transplant Eligible Advanced Heart Failure Patients - A Computer Simulation Study

Abstract

Long term survival after heart transplantation is better than after implantation of VAD, however, the reported survival curves do not represent the whole population of transplant eligible patients, where some die while waiting for the transplantation and do not include the time on the waiting list. The aim of the present study was to use computer simulation model to assess the impact of left ventricular assist device implantation, heart transplantation and combination of both on the overall survival of a group of transplant eligible patients. A computer model was made in Mathematica v12.0 (Wolfram Research, Champaign, IL, USA) to simulate overall survival of a group of virtual patients eligible for heart transplantation in different scenarios, by using Seattle heart failure model score to define baseline survival and published survival curves after heart transplantation, ventricular assist device implantation and time to transplantation to generate individual survival times for each virtual patient. Computer generated data were compared with survival of the transplant eligible patients treated at the University Medical Center Ljubljana, Slovenia. Kaplan-Meier survival curves are presented for baseline, combined waiting list and heart transplantation, waiting list, combined waiting list and high-risk ventricular assist device implantation and combined ventricular assist device implantation and heart transplantation survival. The model has shown that overall group survival after heart transplantation only is much worse than published post-transplant survival due to waiting list mortality. Waiting list mortality is lower than true baseline mortality due to informative censoring. Ventricular assist device implantation is beneficial in higher risk patients but can do more harm in lower risk patients. The combined use of ventricular assist device implantation and heart transplantation has the greatest impact on survival, by decreasing early mortality with ventricular assist device and increasing the long-term survival with transplantation.