Waitlist mortality risk (US-CRS score) distribution among status 1 and 2 adult heart transplant candidates with exceptions

Q: What are the key findings of this study?

Heart transplant candidates with exceptions had significantly lower median US-CRS scores than standard-criteria candidates in Status 1 (45 vs 50, p<0.001) and Status 2 (42 vs 46, p<0.001).

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: Adult heart transplant candidates on the waitlist (n=4480). Intervention: Waitlist status listing by approved exception request vs. Standard-criteria waitlist status listing without exceptions. Primary outcome: Median US-candidate risk score (US-CRS) in Status 1 candidates (p=<0.001).

Q: What does this research mean for the field?

Adult heart transplant candidates granted Status 1 or Status 2 exceptions have significantly lower waitlist mortality risk scores (US-CRS) than non-exception candidates at the same priority levels. Novelty: ClaimNovelty.INCREMENTAL. Consensus alignment: ConsensusAlignment.NEUTRAL.

Q: What question did this study set out to answer?

To assess whether the US-candidate risk score (US-CRS) accurately predicts waitlist mortality for exception candidates and evaluate whether organ allocation priority aligns with mortality risk.

Najiya Fatma; Suhani S. Patel; Grace R. Lyden; Nader Moazami; Brian J. Wayda; William F. Parker; Sommer Elizabeth Gentry

doi:10.1016/j.jhlto.2026.100706

October 12, 2026JHLT OpenOpen Access

Waitlist mortality risk (US-CRS score) distribution among status 1 and 2 adult heart transplant candidates with exceptions

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Key result

Heart transplant candidates with status exceptions show ~5-point lower US-CRS risk scores than standard candidates.

P<0.001
n=4,480

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Why the study?

The study assessed whether the US-candidate risk score (US-CRS) accurately assigns mortality risk for heart transplant candidates with exceptions, and whether the alignment of allocation priority with waitlist mortality risk differs between candidates with and without exceptions.

Does the US-candidate risk score (US-CRS) accurately predict waitlist mortality risk in heart transplant candidates with status exceptions, and how does predicted mortality risk compare between candidates listed with and without exceptions?

Key Points

To assess whether the US-candidate risk score (US-CRS) accurately predicts waitlist mortality for exception candidates and evaluate whether organ allocation priority aligns with mortality risk.
Analyzed national registry data of adult heart transplant candidates, evaluating Status 1 (N=341: 163 without exceptions, 178 with exceptions) and Status 2 (N=1,802: 687 without exceptions, 1,115 with exceptions) candidates.
Assessed US-CRS prediction accuracy across groups using receiver operating characteristic curves and compared score distributions using Kolmogorov-Smirnov, Wilcoxon Rank-Sum, and Chi-squared or Fisher exact tests.
US-CRS mortality prediction accuracy was comparable between candidates with and without exceptions, with an AUC of 0.682 (95% CI 0.594–0.771) versus 0.720 (95% CI 0.629–0.801) in Status 1 and 2.
Median US-CRS was significantly lower for candidates with exceptions than without exceptions in Status 1 (45 [IQR 36–48] vs. 50 [IQR 48-50]; p ≤ 0.05) and Status 2 (42 [IQR 32–47] vs. 46 [IQR 41–49]; p ≤ 0.05).
Scores below 40 were found in 33.13% of Status 1 and 41.28% of Status 2 candidates with exceptions, compared to 1.84% and 19.20% of candidates without exceptions, respectively.

Study Design

Type

Cohort (n=4,480)

Multicenter

Yes

Structured PICO

Does the US-candidate risk score (US-CRS) accurately predict waitlist mortality risk in heart transplant candidates with status exceptions, and how does predicted mortality risk compare between candidates listed with and without exceptions?

P

Population

4,480 adult heart transplant candidates (including 2,143 in Status 1 and 2: 1,293 with exceptions and 850 without exceptions) listed in the US Scientific Registry for Transplant Recipients between 2019 and 2022.

E

Exposure

Heart transplant waitlist status assignment via Regional Review Board (RRB)-approved exception request (candidates with exceptions), evaluated using the 50-point US-candidate risk score (US-CRS) based on 7 variables (albumin, log bilirubin, eGFR, log BNP, NT-proBNP, durable LVAD, and short-term MCS ever used).

C

Comparator

Heart transplant waitlist status assignment via standard clinical criteria without an exception request (candidates without exceptions), evaluated using the US-CRS.

O

Outcome

US-CRS model discrimination (ROC-AUC) for 6-week waitlist mortality and US-CRS score distributions (median [IQR] and proportions below score thresholds of 20, 30, and 40) across waitlist statuses.hard clinical

Main Result

Absolute Event Rate: 45% vs 50%

p-value: p=<0.001

The US-CRS accurately predicts waitlist mortality in heart transplant candidates with exceptions and reveals that over one-third of Status 1 and 2 exception candidates have relatively low predicted mortality risk (<40), supporting the transition to a continuous allocation framework.

Limitations

Did not review individual exception narratives
Small number of cases where exception requests were initially approved and later disapproved
Did not evaluate whether US-CRS accurately reflects mortality risk for smaller candidate subgroups (multi-organ recipients, candidates ineligible for short-term MCS, restrictive or hypertrophic cardiomyopathy)
Changes in temporary MCS utilization and listing practices since the US-CRS development period may affect contemporary performance
Methodology does not directly show that candidates with exceptions have lower average observed mortality than candidates without exceptions
In a very small number of cases, exception requests were initially approved and later disapproved.
Did not evaluate whether the US-CRS accurately reflects mortality risk for smaller candidate subgroups, such as multi-organ recipients, candidates clinically eligible for short-term MCS but unable to receive it, and those with restrictive or hypertrophic cardiomyopathy.
Changes in temporary MCS utilization and listing practices since the US-CRS development period may affect its contemporary performance.
Methodology does not directly show that candidates with exceptions have lower average observed mortality than candidates without exceptions.
Did not review individual exception narratives.

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Implication

Exception candidates in Status 1/2 had lower predicted risk; leaves open whether continuous allocation better aligns priority with mortality.

Abstract

Background The US-candidate risk score (US-CRS) predicts waitlist mortality among heart transplant candidates using seven laboratory, cardiovascular, and cardiac device usage variables on a 50-point scale, with higher scores indicating greater mortality risk. We assessed whether US-CRS accurately assigns mortality risk for exception candidates, and whether the alignment of allocation priority with waitlist mortality risk (US-CRS) differs between candidates with and without exceptions. Methods We compared the performance of US-CRS in candidates with and without exceptions using receiver operating curves. We compared US-CRS distributions using the Kolmogorov-Smirnov (KS) test and examined the proportion of candidates below specific score thresholds in each group. We also compared candidates with and without exceptions using Wilcoxon Rank-Sum test for continuous variables and Pearson's Chi-squared test or Fisher exact test for categorical variables. Results US-CRS is accurate for measuring mortality risk among exception candidates as it is among non-exception candidates. Patients with higher waitlist status had higher median US-CRS. However, the median US-CRS of Status 1 candidates without exceptions (50 [IQR 48-50]) was significantly higher than for candidates with exceptions (45 [36–48]; ( p ≤ 0.05 )), and similarly for Status 2 (46 [41–49] vs. 42 [32–47]; ( p ≤ 0.05 )). Notably, 33.13% of Status 1 and 41.28% of Status 2 candidates with exceptions had US-CRS below 40, compared to only 1.84% and 19.20% of candidates without exceptions, respectively. Conversely, among candidates in Status 3 and 4, candidates with exceptions generally had higher US-CRS than candidates without exceptions. Conclusions Allocation priority under the status system does not align with estimated mortality risk; misalignment is greater for candidates with exceptions. While some exception candidates in Status 1 and 2 do have high estimated mortality risk and legitimately need exceptions, many of these exceptions appear to have been granted to candidates with relatively low medical urgency.

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Cite This Study

Fatma et al. (2026) conducted a cohort in Adult heart transplant candidates on the waitlist (n=4,480). Waitlist status listing by approved exception request vs. Standard-criteria waitlist status listing without exceptions was evaluated on Median US-candidate risk score (US-CRS) in Status 1 candidates (p=<0.001). Heart transplant candidates with exceptions had significantly lower median US-CRS scores than standard-criteria candidates in Status 1 (45 vs 50, p<0.001) and Status 2 (42 vs 46, p<0.001).

synapsesocial.com/papers/6af10ed2a61b6e74a6de156f https://doi.org/10.1016/j.jhlto.2026.100706

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Waitlist mortality risk (US-CRS score) distribution among status 1 and 2 adult heart transplant candidates with exceptions

Figures

Key Points

Study Design

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

Waitlist mortality risk (US-CRS score) distribution among status 1 and 2 adult heart transplant candidates with exceptions

Figures

Key Points

Study Design

Structured PICO

Main Result

Limitations

Ask about this paper

Implication

Abstract

Discussion

Cite This Study

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