Heart allocation status system

The heart allocation status system is the medical-urgency framework used by the Organ Procurement and Transplantation Network (OPTN) to rank adult candidates for deceased-donor heart transplantation in the United States.[1][2] Since October 18, 2018, adult heart candidates have been classified into a six-status system (Status 1 through Status 6), in which Status 1 represents the highest medical urgency and Status 6 the lowest, with each status assessing a candidate's relative short-term risk of dying without a transplant.[1][2] The six-status system replaced an earlier three-tier system (Status 1A, 1B, and 2) that had been in place since the 1990s and was last substantively revised in 2006.[2][3]

The status system determines a candidate's priority within heart allocation; the resulting priority is then applied within the geographic framework in force for hearts, as described in Geographic distribution and acuity circles, and the whole is executed through the match run. Pediatric heart candidates use a separate status system, described below. For the surgical procedure and recipient course, see Heart transplantation.

Background: the three-status system and why it changed

From the 1990s until 2018, adult heart candidates were classified into three tiers, Status 1A (most urgent), Status 1B, and Status 2.[2][3] By the 2010s this system was widely viewed as too coarse.[2][3] The principal reasons for revision were:[1][2]

• the rapid growth in the use of mechanical circulatory support (MCS), including durable left ventricular assist devices (LVADs), biventricular assist devices, total artificial hearts, and extracorporeal membrane oxygenation (ECMO), which the older three statuses did not distinguish well;
• compression at the top of the list, where many heterogeneous candidates were grouped together in Status 1A despite very different risks of death; and
• heavy reliance on exception requests, in which programs sought higher priority for individual candidates whose true urgency the rigid criteria did not capture.

The 2018 revision created more, finer-grained statuses with "more detailed criteria for when and how these treatments are used," aiming to better stratify the highest-risk candidates and reduce waitlist mortality.[1][2]

The six adult statuses

Under the system effective October 18, 2018, adult candidates are assigned to one of six statuses based on clinical criteria, principally the type and complications of mechanical circulatory support, inotrope use, hemodynamic monitoring, and underlying diagnosis.[2][4] To qualify for the highest-priority Status 1 or Status 2, most candidates must also demonstrate objective evidence of severe illness such as cardiogenic shock by hemodynamic or clinical criteria.[4] In summary, as reflected in OPTN policy and the peer-reviewed literature:[2][4]

• Status 1, the most urgent: venoarterial ECMO (VA-ECMO); a non-dischargeable, surgically implanted, non-endovascular biventricular assist device; or a durable mechanical support device with life-threatening ventricular arrhythmias.
• Status 2, a durable LVAD with device malfunction or failure; an intra-aortic balloon pump (IABP); a percutaneous endovascular ventricular assist device; certain surgically implanted non-endovascular LVADs; a dischargeable biventricular/right-ventricular assist device or total artificial heart; or sustained ventricular tachycardia/fibrillation.
• Status 3, a durable LVAD used under a 30-day discretionary period; multiple inotropes, or a single high-dose inotrope, with continuous hemodynamic (pulmonary-artery catheter) monitoring; or a mechanical support device with certain complications.
• Status 4, a stable durable LVAD without complications; continuous inotropic infusion without hemodynamic monitoring; congenital heart disease; hypertrophic or restrictive cardiomyopathy (including amyloidosis); intractable angina; or a retransplant candidate.
• Status 5, candidates listed for at least one other organ in addition to the heart (multi-organ candidates).
• Status 6, all other active candidates.

The exact qualifying criteria, durations, and required documentation for each status are set out in OPTN policy and are periodically revised; the summary above reflects the policy as reproduced in the clinical literature and should be cite-checked against the current OPTN heart-allocation policy before publication.[2][4]

Geographic sharing for hearts

The 2018 policy changed not only the urgency tiers but also the geographic distribution of hearts.[2][5] It removed the donation service area (DSA) as the most-local unit and instead made the most-local level of distribution the candidates listed at transplant hospitals within 250 nautical miles of the donor hospital, with broader sharing for the most urgent statuses.[2][5] This placed hearts among the organs that moved from DSA-based to fixed-distance allocation in the late 2010s, a step on the path toward continuous distribution.[5]

Pediatric heart allocation

Candidates younger than 18 are not assigned to the adult six-status system.[6] Pediatric heart candidates are listed under a separate three-status system, Status 1A, Status 1B, and Status 2, with criteria appropriate to children and congenital heart disease.[6] Because the systems differ, the same physiology can map to different priorities depending on whether the candidate is listed as a child or an adult; for example, certain congenital single-ventricle candidates correspond to adult Status 4, broadly equivalent to pediatric Status 1B.[6]

Continuous distribution for hearts (in development)

The OPTN has been developing a continuous-distribution framework for hearts that would eventually replace the six-status system with a weighted Composite Allocation Score.[7] Work on heart continuous distribution began in 2022; a community values-prioritization exercise was completed in 2024, and as of 2025 the Heart Committee was still refining attribute weights and rating scales.[7] As of mid-2026, heart continuous distribution had not been implemented, and the six-status system remained the operative adult framework; this status should be re-confirmed against the OPTN's continuous-distribution pages, as it is a moving target.[7]

See also

• Heart transplantation
• OPTN allocation policy
• The match run
• Geographic distribution and acuity circles
• Continuous distribution and the Composite Allocation Score

References

• HRSA / OPTN. OPTN/UNOS Board approves revised adult heart allocation system. https://optn.transplant.hrsa.gov/news/optnunos-board-approves-revised-adult-heart-allocation-system-clarifies-exception-points-for-liver-transplant-candidates-with-hepatocellular-carcinoma/
• Policy and oversight of cardiac transplantation (six-status criteria; DSA removal; 250-NM distribution). PMC12082465. https://pmc.ncbi.nlm.nih.gov/articles/PMC12082465/
• UNOS. New adult heart allocation policy in effect. https://unos.org/news/new-adult-heart-allocation-policy-in-effect/
• Impact of new UNOS allocation criteria on heart transplant practices and outcomes (cardiogenic-shock requirement; six statuses). PMC7738116. https://pmc.ncbi.nlm.nih.gov/articles/PMC7738116/
• HRSA / OPTN. Policy modification to lung/thoracic distribution sequence (250 nautical miles). https://optn.transplant.hrsa.gov/news/policy-modification-to-lung-distribution-sequence/
• HRSA / OPTN. Pediatric heart allocation. https://optn.transplant.hrsa.gov/professionals/by-organ/heart-lung/pediatric-heart-allocation/
• HRSA / OPTN. Continuous distribution, heart. https://optn.transplant.hrsa.gov/policies-bylaws/a-closer-look/continuous-distribution/continuous-distribution-heart/