For patients on mechanical circulatory support, a risk index predicts 1-year mortality after heart transplantation, a study suggested, providing a tool to help in the decision between continuing long-term device support and proceeding with a transplantation for this population.
Each 1-point increase in the TRIP-MCS index (c-statistic 0.66), a “simple additive” 75-point scoring system, corresponded with an 8.3% jump in the risk of 1-year mortality (odds ratio 1.08, 95% confidence interval 1.06-1.11), according to Ashish S. Shah, MD, of Vanderbilt Medical Center East in Nashville, Tenn., and colleagues.
“We present a novel, internally cross-validated risk index that accurately predicts mortality in bridge-to-transplant patients,” the authors reported online in JACC: Heart Failure.
Variables associated with mortality included:
Age over 60 (OR 1.69, 95% CI 1.38- 2.06)
Sex mismatch between donor and recipient (OR 1.35, 95% CI 1.10- 1.66)
BMI of 35 or greater (OR 1.97, 95% CI 1.37- 2.83)
Mechanical ventilation at time of transplant (OR 2.03, 95% CI 1.33- 3.09)
“This score may serve to add structure to shared decision-making conversations between patient and provider by quantitating the short- and mid-term risks of transplantation. From society’s perspective, organs remain a scarce resource and it may be reasonable to question the utility of transplanting a stable, or an especially high-risk, mechanical circulatory support patient,” they concluded.
However, high TRIP-MCS scorers are likely to be patients “heading toward death on mechanical circulatory support or toward ‘bail out’ high risk transplant. In this setting, one could argue the recipient may be too sick to allow for judicious organ allocation; a lower risk recipient should get the organ,” suggested Jennifer Cowger, MD, of St. Vincent Heart Center of Indianapolis.
What’s more, the model performed only “modestly well,” she wrote in an accompanying editorial. “Is a model AUC [area under the curve] of 0.66 good enough to comfortably make this call without taking into account the other unmeasured factors?”
Shah’s study included 6,036 patients on mechanical circulatory support who received heart transplants between 2000 and 2013. Investigators retrieved data from the United Network for Organ Sharing (UNOS).
Shah and colleagues acknowledged that “though TRIP-MCS works well for current devices, it is unclear whether it will continue to do so as technology evolves.”
“Mechanical circulatory support is presently in a state of continued and rapid evolution,” Cowger agreed.
“Mortality risk prediction during mechanical circulatory support is, therefore, also an evolving process and new correlates of risk will continually be identified while (simultaneously) previously known predictors of mechanical circulatory support mortality may change in their magnitudes of attributable risk,” she wrote.
Shah and Cowger reported no relevant conflicts of interest.