Trends in the Use of Inotropes to List Adult Heart Transplant Candidates at Status 1A

Donor heart allocation systems in Europe. A scientific statement of the Heart Failure Association of the ESC

Heart transplantation remains the gold standard for treatment of most patients with advanced heart failure (HF), but despite improvements of organ recovery and utilization, donor heart scarcity remains a critically limiting factor. Detailed heart allocation systems (HASs) are in place to ensure use of organs for appropriate candidates, In Europe multiple, different HASs have evolved in different countries or communities of collaborating countries, like Eurotransplant or Scandiatransplant. In this scientific statement, we review the generic ethical and practical principles underlying allocation principles and examine and describe different European HASs with the purpose of discussing impact of outcomes for patients with advanced HF. It is shown that European HASs differ significantly with respect to which patients are prioritized and the methods by which the prioritization is performed. It is argued that the most commonly used parameter to describe success of a HAS, namely 1-year survival after heart transplantation, is a poor metric of HAS performance. The impact of HASs should be evaluated by several measures such as survival from listing, time to transplantation, the characteristics of patients undergoing heart transplantation, and over a longer time interval to understand the balance of early and late post-transplant risks and benefit. Mapping European HASs is a step towards understanding these factors and further research should determine the optimal HAS in a given HF population at a given time.

Bridge to Transplantation: Policies Impact Practices

Since the development of the first heart allocation system in 1988 to the most recent heart allocation system in 2018, the road to heart transplantation has continued to evolve. Policies were shaped with advances in temporary and durable left ventricular assist devices as well as prioritization of patients based on degree of illness. Herein, we review the changes in the heart allocation system over the past several decades and the impact of practice patterns across the United States.

Proposal and Rationale for a Cardioethics Curriculum

The modern practice of cardiovascular medicine involves many ethical controversies in the care of our complex patients. Accordingly, we propose a framework for a practical, clinically based "cardioethics" curriculum that might be incorporated into fellowship training to prepare cardiologists to cope with increasingly complex ethical dilemmas. This work can also be adopted into continuing medical education for cardiologists and other cardiovascular practitioners given the critical importance of collaborative care in cardiology. We discuss heart transplant allocation, futility concerns, withdrawing care, advance care planning, conflicts of interests, and distributive justice. Sound ethical decision-making in cardiology requires a combination of extensive technical knowledge, nuanced appreciation of individual patient goals and values, and thoughtful application of ethical principles and reasoning. Cardiologists have an exceptionally broad toolkit of medications and interventions to address high-stakes disease states. We should maintain a similarly broad ethical toolkit to provide the best care for our patients.

The Accuracy of Initial U.S. Heart Transplant Candidate Rankings

BACKGROUND

The U.S. heart allocation system ranks candidates with only 6 treatment-based categorical "statuses" and ignores many objective patient characteristics.

OBJECTIVES

This study sought to determine the effectiveness of the standard 6-status ranking system and several novel prediction models in identifying the most urgent heart transplant candidates.

METHODS

The primary outcome was death before receipt of a heart transplant. The accuracy of the 6-status system was evaluated using Harrell's C-index and log-rank tests of Kaplan-Meier estimated survival by status for candidates listed postpolicy (November 2018 to March 2020) in the Scientific Registry of Transplant Recipients data set. The authors then developed Cox proportional hazards models and random survival forest models using prepolicy data (2010-2017). The predictor variables included age, diagnosis, laboratory measurements, hemodynamics, and supportive treatment at the time of listing. The performance of these models was compared with the candidate's 6-status ranking in the postpolicy data.

RESULTS

Since policy implementation, the 6-status ranking at listing has had moderate ability to rank-order candidates (C-index: 0.67). Statuses 4 and 6 had no significant difference in survival (P = 0.80), and status 5 had lower survival than status 4 (P < 0.001). Novel multivariable prediction models derived with prepolicy data ranked candidates correctly more often than the 6-status rankings (Cox proportional hazards model C-index: 0.76; random survival forest model C-index: 0.74). Objective physiologic measurements, such as glomerular filtration rate, had high variable importance.

CONCLUSIONS

The treatment-based 6-status heart allocation system has only moderate ability to rank-order candidates by medical urgency. Predictive models that incorporate physiologic measurements can more effectively rank-order heart transplant candidates by urgency.

Practical application of the French two-score heart allocation scheme: Insights from a high-volume heart transplantation centre

BACKGROUND

In 2018, a cardiac allocation scheme based on an individual score considering the risk of death both on the waitlist and after heart transplantation was implemented in France.

AIMS

To analyse the practical application of the pre- and post-transplant risk score in a French high-volume heart transplantation centre.

METHODS

All consecutive adult patients listed for a first non-combined heart transplantation between 02 January 2018 and 30 June 2022 at our centre were included. Baseline characteristics of candidates and recipients were retrieved from the national CRISTAL registry. Both scores were calculated at listing and at transplant.

RESULTS

Overall, 364 patients were included. During follow-up, 257 patients (70.6%) were transplanted, and 57 (15.6%) died or were removed from the waitlist. Post-transplant 3-month survival was 84.8%. Total bilirubin and natriuretic peptides had the most important weight in the pretransplant risk score. This score had a major impact on waitlist outcomes: quartile 1 was characterized by low access to heart transplantation (58.2%) and risk of death on the waitlist (9.9%) compared with quartile 4 (heart transplantation rate 74.1%, mortality on the waiting list>20%). According to the post-transplant risk score, a minimal number of candidates were considered ineligible for heart transplantation (<1%), but 12.4% were contraindicated to at least one donor category. The number of contraindicated donor categories had a significant impact on waitlist outcomes. Although adequately calibrated, the post-transplant score had a limited discrimination (area under the curve 0.65, 95% confidence interval 0.59-0.71).

CONCLUSION

Our results highlight the major impact of pre- and post-transplantation risk scores on waitlist outcomes following the allocation scheme update.

Impact of the 2018 French two-score allocation scheme on the profile of heart transplantation candidates and recipients: Insights from a high-volume centre

BACKGROUND

In 2018, a new cardiac allograft allocation scheme, based on an individual scoring system, considering the risk of death both on the waiting list and after heart transplantation, was implemented in France.

AIM

To assess the impact of this new scheme on the profile of transplantation candidates and recipients.

METHODS

In this single-centre retrospective study, we included consecutive patients listed and/or transplanted between 01 January 2012 and 30 September 2021 at La Pitié-Salpêtrière Hospital. Baseline characteristics of patients were retrieved from the national CRISTAL registry and were compared according to the type of allocation scheme (before or after 2018).

RESULTS

A total of 1098 newly listed transplantation candidates and 855 transplant recipients were included. One-year mortality rates after listing and after transplantation were 12.4% and 20%, respectively. At listing, the proportion of candidates on inotropes significantly declined following the scheme update (26.3 versus 20.9%; P=0.038), reflecting a change in medical practice. At transplantation, recipients had worse kidney function (estimated glomerular filtration rate<60mL/min/1.73 m²: old scheme, 29.7%; new scheme, 46.4%; P<0.001) and were more likely to be on extracorporeal membrane oxygenation support (33.5% versus 28.1%; P=0.080) under the new scheme, reflecting the prioritization of more severe patients. Outcomes after transplantation were not significantly influenced by the allocation system.

CONCLUSIONS

The implementation of the 2018 French allocation scheme had a limited impact on the profile of transplantation candidates, but selected more severe patients for transplantation without significant impact on outcomes after transplantation.

Donor heart selection: Evidence-based guidelines for providers

The proposed donor heart selection guidelines provide evidence-based and expert-consensus recommendations for the selection of donor hearts following brain death. These recommendations were compiled by an international panel of experts based on an extensive literature review.

A challenge to equity in transplantation: Increased center-level variation in short-term mechanical circulatory support use in the context of the updated U.S. heart transplant allocation policy

BACKGROUND

The United States National Organ Procurement Transplant Network (OPTN) implemented changes to the adult heart allocation system to reduce waitlist mortality by improving access for those at greater risk of pre-transplant death, including patients on short-term mechanical circulatory support (sMCS). While sMCS increased, it is unknown whether the increase occurred equitably across centers.

METHODS

The OPTN database was used to assess changes in use of sMCS at time of transplant in the 12 months before (pre-change) and after (post-change) implementation of the allocation system in October 2018 among 5,477 heart transplant recipients. An interrupted time series analysis comparing use of bridging therapies pre- and post-change was performed. Variability in the proportion of sMCS use at the center level pre- and post-change was determined.

RESULTS

In the month pre-change, 9.7% of patients were transplanted with sMCS. There was an immediate increase in sMCS transplant the following month to 32.4% - an absolute and relative increase of 22.7% and 312% (p < 0.001). While sMCS use was stable pre-change (monthly change 0.0%, 95% CI [-0.1%,0.1%]), there was a continuous 1.2%/month increase post-change ([0.6%,1.8%], p < 0.001). Center-level variation in sMCS use increased substantially after implementation, from a median (interquartile range) of 3.85% (10%) pre-change to 35.7% (30.6%) post-change (p < 0.001).

CONCLUSIONS

Use of sMCS at time of transplant increased immediately and continued to expand following heart allocation policy changes. Center-level variation in use of sMCS at the time of transplant increased compared to pre-change, which may have negatively impacted equitable access to heart transplantation.

Development and validation of specific post-transplant risk scores according to the circulatory support status at transplant: A UNOS cohort analysis

BACKGROUND

The clinical use of post-transplant risk scores is limited by their poor statistical performance. We hypothesized that developing specific prognostic models for each type of circulatory support at transplant may improve risk stratification.

METHODS

We analyzed the UNOS database including contemporary, first, non-combined heart transplantations (2013-2018). The endpoint was death or retransplantation during the first year post-transplant. Three different circulatory support statuses at transplant were considered: no support, durable mechanical support and temporary support (inotropes, temporary mechanical support). We generated 1,000 bootstrap samples that we randomly split into derivation and test sets. In each sample, we derived an overall model and 3 specific models (1 for each type of circulatory support) using Cox regressions, and compared, in the test set, their statistical performance for each type of circulatory support.

RESULTS

A total of 13,729 patients were included; 1,220 patients (8.9%) met the composite endpoint. Circulatory support status at transplant was associated with important differences in baseline characteristics and distinct prognosis (p = 0.01), interacted significantly with important predictive variables included in the overall model, and had a major impact on post-transplant predictive models (type of variables included and their corresponding hazard ratios). However, specific models suffered from poor discriminative performance and significantly improved risk stratification (discrimination, reclassification indices, calibration) compared to overall models in a very limited proportion of bootstrap samples (<15%). These results were consistent across several sensitivity analyzes.

CONCLUSION

Circulatory support status at transplant reflected different disease states that influenced predictive models. However, developing specific models for each circulatory support status did not significantly improve risk stratification.

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

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.

Practice Changes at U.S. Transplant Centers After the New Adult Heart Allocation Policy

BACKGROUND

In October 2018, the U.S. heart allocation system expanded the number of priority "status" tiers from 3 to 6 and added cardiogenic shock requirements for some heart transplant candidates listed with specific types of treatments.

OBJECTIVES

This study sought to determine the impact of the new policy on the treatment practices of transplant centers.

METHODS

Initial listing data on all adult heart candidates listed from December 1, 2017 to April 30, 2019 were collected from the Scientific Registry of Transplant Recipients. The status-qualifying treatments (or exception requests) and hemodynamic values at listing of a post-policy cohort (December 2018 to April 2019) were compared with a seasonally matched pre-policy cohort (December 2017 to April 2018). Candidates in the pre-policy cohort were reclassified into the new priority system statuses by using treatment, diagnosis, and hemodynamics.

RESULTS

Comparing the post-policy cohort (N = 1,567) with the pre-policy cohort (N = 1,606), there were significant increases in listings with extracorporeal membrane oxygenation (+1.2%), intra-aortic balloon pumps (+ 4 %), and exceptions (+ 12%). Listings with low-dose inotropes (-18%) and high-dose inotropes (-3%) significantly decreased. The new priority status distribution had more status 2 (+14%) candidates than expected and fewer status 3 (-5%), status 4 (- 4%) and status 6 (-8%) candidates than expected (p values <0.01 for all comparisons).

CONCLUSIONS

After implementation of the new heart allocation policy, transplant centers listed more candidates with extracorporeal membrane oxygenation, intra-aortic balloon pumps, and exception requests and fewer candidates with inotrope therapy than expected, thus leading to significantly more high-priority status listings than anticipated. If these early trends persist, the new allocation system may not function as intended.

A change of heart: Preliminary results of the US 2018 adult heart allocation revision

In 2018, the Organ Procurement and Transplantation Network (OPTN) modified adult heart allocation to better stratify candidates and provide broader access to the most medically urgent candidates. We analyzed OPTN data that included waiting list and transplant characteristics, geographical distribution, and early outcomes 1 year before (pre: October 18, 2017-October 17, 2018) and following (post: October 18, 2018-October 17, 2019) implementation. The number of adult heart transplants increased from 2954 pre- to 3032 postimplementation. Seventy-eight percent of transplants in the post era were for the most medically urgent (statuses 1-3) compared to 68% for status 1A in the pre era. The median distance between the donor hospital and transplant center increased from 83 to 216 nautical miles, with an increase in total ischemic time from 3 to 3.4 hours (all P < .001). Waiting list mortality was not different across eras (14.8 vs 14.9 deaths per 100 patient-years pre vs post respectively). Posttransplant patient survival was not different, 93.6% pre and 92.8% post. There is early evidence that the heart allocation policy has enhanced stratification of candidates by their medical urgency and broader distribution for the most medically urgent candidates with minimal impact on overall waiting list mortality and posttransplant outcomes.

Epistemic Authority and Trust in Shared Decision Making About Organ Transplantation

Patient epistemic authority acknowledges respect for a patient's knowledge claims, an important manifestation of patient autonomy that facilitates shared decision making in medicine. Given the scarcity of deceased donor organs, transplantation programs state that patient promises of compliance cannot be taken at face value and exclude candidates deemed untrustworthy. This article argues that transplant programs frequently lack the data to make this utilitarian calculation accurately, with the result that, in practice, the psychosocial evaluation of potential transplant candidates is discriminatory and unfair. Historically excluded candidates, such as patients suffering from alcohol use, have turned out to benefit highly from transplantation. Transplant programs should tend to trust patients when they claim to be good potential organ stewards, thereby respecting patient autonomy, advancing justice, and saving more lives.

Association of Transplant Center With Survival Benefit Among Adults Undergoing Heart Transplant in the United States

IMPORTANCE

In the United States, the number of deceased donor hearts available for transplant is limited. As a proxy for medical urgency, the US heart allocation system ranks heart transplant candidates largely according to the supportive therapy prescribed by transplant centers.

OBJECTIVE

To determine if there is a significant association between transplant center and survival benefit in the US heart allocation system.

DESIGN, SETTING, AND PARTICIPANTS

Observational study of 29 199 adult candidates for heart transplant listed on the national transplant registry from January 2006 through December 2015 with follow-up complete through August 2018.

EXPOSURES

Transplant center.

MAIN OUTCOMES AND MEASURES

The survival benefit associated with heart transplant as defined by the difference between survival after heart transplant and waiting list survival without transplant at 5 years. Each transplant center's mean survival benefit was estimated using a mixed-effects proportional hazards model with transplant as a time-dependent covariate, adjusted for year of transplant, donor quality, ischemic time, and candidate status.

RESULTS

Of 29 199 candidates (mean age, 52 years; 26% women) on the transplant waiting list at 113 centers, 19 815 (68%) underwent heart transplant. Among heart transplant recipients, 5389 (27%) died or underwent another transplant operation during the study period. Of the 9384 candidates who did not undergo heart transplant, 5669 (60%) died (2644 while on the waiting list and 3025 after being delisted). Estimated 5-year survival was 77% (interquartile range [IQR], 74% to 80%) among transplant recipients and 33% (IQR, 17% to 51%) among those who did not undergo heart transplant, which is a survival benefit of 44% (IQR, 27% to 59%). Survival benefit ranged from 30% to 55% across centers and 31 centers (27%) had significantly higher survival benefit than the mean and 30 centers (27%) had significantly lower survival benefit than the mean. Compared with low survival benefit centers, high survival benefit centers performed heart transplant for patients with lower estimated expected waiting list survival without transplant (29% at high survival benefit centers vs 39% at low survival benefit centers; survival difference, -10% [95% CI, -12% to -8.1%]), although the adjusted 5-year survival after transplant was not significantly different between high and low survival benefit centers (77.6% vs 77.1%, respectively; survival difference, 0.5% [95% CI, -1.3% to 2.3%]). Overall, for every 10% decrease in estimated transplant candidate waiting list survival at a given center, there was an increase of 6.2% (95% CI, 5.2% to 7.3%) in the 5-year survival benefit associated with heart transplant.

CONCLUSIONS AND RELEVANCE

In this registry-based study of US heart transplant candidates, transplant center was associated with the survival benefit of transplant. Although the adjusted 5-year survival after transplant was not significantly different between high and low survival benefit centers, compared with centers with survival benefit significantly below the mean, centers with survival benefit significantly above the mean performed heart transplant for recipients who had significantly lower estimated expected 5-year waiting list survival without transplant.

Geographic Variation in the Treatment of U.S. Adult Heart Transplant Candidates

BACKGROUND

The current U.S. priority ranking for heart candidates is based on treatment intensity, not objective markers of severity of illness. This system may encourage centers to overtreat candidates.

OBJECTIVES

This study sought to describe national variation in the intensity of treatment of adult heart transplantation candidates and identify center-level predictors of potential overtreatment.

METHODS

The registrations of all U.S. adult heart transplantation candidates from 2010 to 2015 were collected from the SRTR (Scientific Registry of Transplant Recipients). "Potential overtreatment" was defined as treatment of a candidate who did not meet American Heart Association cardiogenic shock criteria with either high-dose inotropes or an intra-aortic balloon pump. Multilevel logistic regression and propensity score models were used to adjust for candidate variability at each center. Center-level variables associated with potential overtreatment were identified.

RESULTS

From 2010 to 2015, 108 centers listed 12,762 adult candidates who were not in cardiogenic shock for heart transplantation. Of these, 1,471 (11.6%) were potentially overtreated with high-dose inotropes or intra-aortic balloon pumps. In the bottom quartile of centers, only 2.1% of candidates were potentially overtreated compared with 27.6% at top quartile centers, an interquartile difference of 25.5% (95% confidence interval: 21% to 30%). Adjusting for candidate differences did not significantly alter the interquartile difference. Local competition with 2 or more centers increased the odds of potential overtreatment by 50% (adjusted odds ratio: 1.50; 95% confidence interval: 1.07 to 2.11).

CONCLUSIONS

There is wide variation in the treatment practices of adult heart transplantation centers. Competition for transplantable donor hearts is associated with the potential overtreatment of hemodynamically stable candidates. Overtreatment may compromise the fair and efficient allocation of scarce deceased donor hearts.

Application of competing risks analysis improved prognostic assessment of patients with decompensated chronic heart failure and reduced left ventricular ejection fraction

OBJECTIVE

The Kaplan-Meier method may overestimate absolute mortality risk (AMR) in the presence of competing risks. Urgent heart transplantation (UHT) and ventricular assist device implantation (VADi) are important competing events in heart failure. We sought to quantify the extent of bias of the Kaplan-Meier method in estimating AMR in the presence of competing events and to analyze the effect of covariates on the hazard for death and competing events in the clinical model of decompensated chronic heart failure with reduced ejection fraction (DCHFrEF).

STUDY DESIGN AND SETTING

We studied 683 patients. We used the cumulative incidence function (CIF) to estimate the AMR at 1 year. CIF estimate was compared with the Kaplan-Meier estimate. The Fine-Gray subdistribution hazard analysis was used to assess the effect of covariates on the hazard for death and UHT/VADi.

RESULTS

The Kaplan-Meier estimate of the AMR was 0.272, whereas the CIF estimate was 0.246. The difference was more pronounced in the patient subgroup with advanced DCHF (0.424 vs. 0.338). The Fine-Gray subdistribution hazard analysis revealed that established risk markers have qualitatively different effects on the incidence of death or UHT/VADi.

CONCLUSION

Competing risks analysis allows more accurately estimating AMR and better understanding the association between covariates and major outcomes in DCHFrEF.