Statistical performance of 16 posttransplant risk scores in a contemporary cohort of heart transplant recipients

Abstract

Accurate risk stratification of early heart transplant failure is required to avoid futile transplants and rationalize donor selection. We aimed to evaluate the statistical performance of existing risk scores on a contemporary cohort of heart transplant recipients. After an exhaustive search, we identified 16 relevant risk scores. From the UNOS database, we selected all first noncombined adult heart transplants performed between 2014 and 2017 for validation. The primary endpoint was death or retransplant during the first year posttransplant. For all scores, we analyzed their association with outcomes, sensitivity, specificity, likelihood ratios, and discrimination (concordance index and overlap of individual scores). The cohort included 9396 patients. All scores were significantly associated with the primary outcome (P < .001 for all scores). Their likelihood ratios, both negative and positive, were poor. The discriminative performance of all scores was limited, with concordance index ranging from 0.544 to 0.646 (median 0.594) and an important overlap of individual scores between patients with or without the primary endpoint. Subgroup analyses revealed important variation in discrimination according to donor age, recipient age, and the type of assist device used at transplant. Our findings raise concerns about the use of currently available scores in the clinical field.

Utility of the IMPACT score for predicting heart transplant mortality. Analysis on a contemporary cohort of the Spanish Heart Transplant Registry

“…Donor age is a well-known predictor of graft loss at 1 year and its implication in HT prognosis has been largely demonstrated, increasing mortality by around 20% for every 10 years. 11,13,16,19,21 Unlike the ISHLT series, where the mean donor age remains stable around 35 years, 14 in Spain we have witnessed a progressive increase in the mean donor age, being nowadays almost 45 years. 15 Similarly, rates of gender mismatch for male recipients, which has been shown to increase 1-year mortality by 40%, 22 are significantly higher in our series compared to the data from the ISHLT registry (22% vs. 16%).…”

“…On the other hand, as we previously mentioned, certain variables related to the donor have a negative impact on the short‐term prognosis after HT. Donor age is a well‐known predictor of graft loss at 1 year and its implication in HT prognosis has been largely demonstrated, increasing mortality by around 20% for every 10 years 11,13,16,19,21 . Unlike the ISHLT series, where the mean donor age remains stable around 35 years, 14 in Spain we have witnessed a progressive increase in the mean donor age, being nowadays almost 45 years 15 .…”

“…Our findings suggest that the performance of the IMPACT score could UNOS database (2014-2017). 13 They found that all risk scores were significantly associated with post-HT outcomes. However, their statistical performance was poor (C-statistic ranged from .544 to .646) and varied across subgroup of patients (older donors, older recipients and types of mechanical circulatory support).…”

“…Recently, Coutance et al. performed an extensive evaluation of the statistical performance of 16 different predictive models aimed at stratifying the risk of early HT failure (death or retransplantation) based on preoperative variables in a large contemporary cohort of 9,396 HT recipients derived from the UNOS database (2014‐2017) 13 . They found that all risk scores were significantly associated with post‐HT outcomes.…”

Predictors of Survival After Heart Transplant in the New Allocation System: A UNOS Database Analysis

“…Although many of the risk factors for posttransplant outcomes in the current era are similar to those identified under the former allocation system or from listing systems outside the United States, potentially important differences are noted. The most frequently identified recipient predictors in prior risk scores, 1,2 including age, renal dysfunction, elevated bilirubin, mechanical ventilation, and the presence of durable LVAD remain key predictors under the current allocation system. Other recipient predictors in the current era, including Black race, blood group O, mean PAP, diabetes, and etiology of heart failure, were less frequently identified as predictors in previous risk scores (cite).…”