Clinical and technical evidence

A literature search was done for this briefing in accordance with the published process and methods statement. This briefing includes the most relevant/best publicly-available evidence relating to the clinical and cost effectiveness of the technology. The literature search strategy, evidence selection methods and detailed data extraction tables are available on request by contacting

Published evidence

Five studies including a total of 158 heart transplants were selected for inclusion and are summarised in this briefing

Evidence on the use of the OCS Heart system following donation after brainstem death published before December 2015 (including evidence from PROCEED II, a prospective, randomised controlled trial by Ardehali et al. 2015) is summarised in NICE interventional procedure guidance on normothermic extracorporeal preservation of hearts for transplantation following donation after brainstem death, and therefore has not been included in this briefing. No studies published before December 2015 examined the use of the OCS Heart system following donation after circulatory death. The guidance concludes that the OCS Heart system can extend heart preservation times compared to cold storage, for hearts donated after brainstem death.

Two studies reported as abstracts compared patient survival after transplant using the OCS Heart system compared with cold storage preservation. One of these studies reported 2-year patient survival (Esmailian et al. 2016) and the other reported 30-day survival in patients who had left ventricular assist device treatment as a bridge to transplant (Garcia Saez et al. 2015).

Two non-comparative studies reported 2- and 4-year patient survival of people given donor hearts with extended transplantation time or extended donor criteria (donors with 1 or more risk factors; Garcia Saez et al. 2016 and Yeter et al. 2014). One full publication (Messer et al. 2016) looked at the use of the OCS Heart system for functional assessment and transplantation of donor hearts after circulatory death. Overall, no adverse events were reported and the OCS Heart system was found to have similar survival at 30 days and 2 years in comparison with cold ischaemic storage preservation for donation after brainstem death.

Table 1 summarises the clinical evidence as well as its strengths and limitations.

Strengths and limitations of the evidence

Two out of 5 studies were done outside of the UK. Operative and post-operative practices may vary in different countries, which may affect patient outcomes and the generalisability of these studies to the NHS.

Four studies were conference abstracts and therefore lacked detail on methodology. They did not report a sample size calculation and it is unclear whether they were adequately powered to detect differences in outcomes.

One study (Esmailian et al. 2016) used a subset of patients from PROCEED II, included in NICE's interventional procedure guidance on normothermic extracorporeal preservation of hearts for transplantation following donation after brainstem death to assess 2-year outcomes including survival and non-fatal major cardiac events.

Table 1: Summary of selected studies

Study size, design and location

Intervention and comparator(s)


Strengths and limitations

Esmailian et al. (2016)

38 patients




The Organ Class System Heart (OCS) (n=19) compared with standard cold storage (n=19).

There was no significant difference in the 2-year outcomes (patient survival rate, cardiac allograft vasculopathy, any-treated rejection, biopsy-proven cellular rejection, biopsy-proven antibody-mediated rejection or non-fatal major cardiac events) between the OCS group and the cold storage group.

This study used data from PROCEED II, which provided a randomised controlled trial (RCT) comparison of OCS with cold storage.

Garcia Saez et al. (2016)

60 patients

Prospective observational study



OCS in standard criteria donors (n=24) and extended criteria donors, defined as having at least 1 risk factor from the following (n=36): left ventricular ejection fraction < 50%, left ventricular hypertrophy, interventricular septum in diastole > 14 mm, donor cardiac arrest, coronary artery disease, known cocaine abuse or circulatory death (DCD).

Heart recipients were comparable in both groups. Transport time was ≥2.5 hours in 26 donors. One-month, 1-year, and 2-year survival were similar between the two groups.

This was a prospective observational study with long-term survival data

(2 years), but there was no-comparative intervention.

Messer et al. (2016)

13 patients

Prospective non-comparative feasibility and clinical phase study



Adult DCD donors.

Four hearts were assessed in the feasibility phase and 2 were deemed unsuitable for transplantation after functional assessment.

Nine DCD hearts were transplanted in the clinical phase with 100% patient and heart survival. There were no episodes of rejection (total of 1436 patient days, range 48-297 days).

The study had limited follow-up time.

Garcia Saez et al. (2015),

30 patients

Retrospective study



Continuous flow left ventricular assist device (LVAD) transplant with grafts preserved with OCS (n=15) compared with cold storage preservation (n=15).

Patient survival at 30 days was significantly better in patients whose donor heart was in the OCS group in comparison with the cold storage preservation group.

The study is limited in that it was retrospective and provided shorter-term outcomes (30-day survival). The study was done in a subgroup population of LVAD bridge-to-transplant patients which means it may not be generalisable to all heart transplant patients.

Yeter et al. (2014),

21 donor hearts

Unclear study design



OCS (no comparator) in cases of extended organ transportation time and extended donor criteria.

The median time the heart spent ex-vivo was 388 minutes. There was a high rate of freedom from cardiac related death at 30 days and 6 months (95%). This was slightly lower at 1 year and 4 years (87%).

The study provided data on long-term survival (4 years), but the study design is unclear and it lacked comparison with cold storage preservation.

Recent and ongoing studies

One ongoing trial using the OCS Heart system were identified in the preparation of this briefing.

  • NCT02323321 (EXPANDHeart): a US-based, interventional efficacy study to determine the effectiveness of the OCS Heart system to preserve donor hearts that may not meet current standard donor heart acceptance criteria for transplant. This is an ongoing study with estimated study completion date in November 2017.