The Transplantation Risk Index in Patients with Mechanical Circulatory Support (TRIP-MCS) may accurately predict 1-year mortality risk after cardiac bridge-to-transplantation, according to research published in JACC: Heart Failure.
Currently, there are very few tools available to help decide between transplantation and continuing long-term device support for patients bridging with MCS. Therefore, researchers sought to develop a risk index specific to patients on MCS that would predict 1-year mortality after orthopedic heart transplantation (OHT) using data from the United Network for Organ Sharing database.
The open cohort included 6036 patients with MCS who underwent OHT between 2000 and 2013. The derivation group consisted of 80% of the total patients and 20% were assigned to the validation group. The investigators developed a 75-point scoring system from 9 recipient and 4 donor variables. Points for the additive risk index were apportioned based on relative effect on the odds of 1-year mortality.
“This model in turn was translated into a simple scoring system that accurately predicts 1-year mortality in both our derivation and our validation samples, and this risk impacts survival up to 3 years from the time of transplantation,” the authors wrote. “This index may help inform prognosis, organ allocation, and the complex decisions regarding bridge-to-transplantation versus bridge-to-destination therapy.”
The average score in the validation cohort was 14.4 ± 7.7, but scores ranged from 0 to 57. Each 1 point increase predicted an 8.3% increase in 1-year mortality risk (odds ratio: 1.08; 95% confidence interval: 1.06-1.11).
TRisk scores were divided into low (0 to 10), intermediate (11 to 20), and high (>20) cohorts and the average predicted 1-year mortality rates were calculated. The predicted mortality rates were 8.6% for the low-risk cohort, 12.8% for the intermediate-risk cohort, and 31% for the high-risk cohort.
Strongest risk predictors included recipient BMI, renal function, and need for mechanical ventilation.
The authors recommended future studies compare the risk of transplantation with the risks of remaining on long-term MCS. “A clearer understanding of the role of cardiac transplantation in the setting of adequate [MCS] will inform shared clinical decision-making as well as policy regarding transplant priority status and organ allocation,” they concluded.
Johnston LE, Grimm JC, Magruder T, Shah AS. Development of a transplantation risk index in patients with mechanical circulatory support (TRIP-MCS): a decision support tool. JACC Heart Failure. 2016. doi: 10.1016/j.jchf.2015.11.009.