Oxygenated machine perfusion at room temperature as an alternative for static cold storage in porcine donor hearts.

BACKGROUND: There is a continued interest in ex situ heart perfusion as an alternative strategy for donor heart preservation. We hypothesize that oxygenated machine perfusion of donor hearts at a temperature that avoids both normothermia and deep hypothermia offers adequate and safe preservation. METHODS: Cardioplegia-arrested porcine donor hearts were randomly assigned to six hours of preservation using cold storage (CS, n = 5) or machine perfusion using an oxygenated acellular perfusate at 21°C (MP, n = 5). Subsequently, all grafts were evaluated using the Langendorff method for 120 min. Metabolic parameters and histology were analyzed. Systolic function was assessed by contractility and elastance. Diastolic function was assessed by lusitropy and stiffness. RESULTS: For both groups, in vivo baseline and post-Langendorff biopsies were comparable, as were lactate difference and myocardial oxygen consumption. Injury markers gradually increased and were comparable. Significant weight gain was seen in MP (p = 0.008). Diastolic function was not impaired in MP, and lusitropy was superior from 30 min up to 90 min of reperfusion. Contractility was superior in MP during the first hour of evaluation. CONCLUSION: We conclude that the initial functional outcome of MP-preserved hearts was transiently superior compared to CS, with no histological injury post-Langendorff. Our machine perfusion strategy could offer feasible and safe storage of hearts prior to transplantation. Future studies are warranted for further optimization.

Donor Heart Preservation with Hydrogen Sulfide: A Systematic Review and Meta-Analysis.

Preclinical studies have shown that postconditioning with hydrogen sulfide (H2S) exerts cardioprotective effects against myocardial ischemia-reperfusion injury (IRI). The aim of this study was to appraise the current evidence of the cardioprotective effects of H2S against IRI in order to explore the future implementation of H2S in clinical cardiac transplantation. The current literature on H2S postconditioning in the setting of global myocardial ischemia was systematically reviewed and analyzed, performing meta-analyses. A literature search of the electronic databases Medline, Embase and Cinahl identified 1835 studies that were subjected to our pre-defined inclusion criteria. Sixteen studies were considered eligible for inclusion. Postconditioning with H2S showed significant robust effects with regard to limiting infarct size (standardized mean difference (SMD) = -4.12, 95% CI [-5.53--2.71], p < 0.00001). Furthermore, H2S postconditioning consistently resulted in a significantly lower release of cardiac injury markers, lower levels of oxidative stress and improved cardiac function. Postconditioning with slow-releasing H2S donors offers a valuable opportunity for novel therapies within cardiac preservation for transplantation. Before clinical implication, studies evaluating the long-term effects of H2S treatment and effects of H2S treatment in large animal studies are warranted.

Ex Situ Perfusion of Hearts Donated After Euthanasia: A Promising Contribution to Heart Transplantation.

Organ donation after euthanasia is performed in an increasing number of countries. In this donation after circulatory death procedure, it has not been possible to donate the heart. Recent literature, however, reports positive results of heart donation after circulatory death. Therefore, patients who donate organs following euthanasia might be suitable candidates for heart donation. We want to confirm this assumption by sharing the results of 2 cases of heart donation following euthanasia with ex situ subnormothermic heart preservation. Our aim is to raise awareness of the potential of heart donation following euthanasia for both clinical transplantation and research. METHODS: The data of 2 consecutive heart donations following euthanasia were collected prospectively. Informed consent was obtained from the patients themselves for heart donation for research purposes. An acellular oxygenated subnormothermic machine perfusion strategy was used to preserve both donor hearts. Subsequently, the hearts were evaluated on a normothermic perfusion machine using a balloon in the left ventricle. RESULTS: Heart donation following euthanasia was feasible without significant changes in existing retrieval protocols. Duration of machine perfusion preservation was 408 and 432 minutes, for heart 1 and 2, respectively. For heart 1, developed pressure (Pdev) was 119 mm Hg, maximal rate of pressure rise (dP/dtmax), and fall (dP/dtmin) were 1524 mm Hg/s and -1057 mm Hg/s, respectively. For heart 2, Pdev was 142 mm Hg, dP/dtmax was 1098 mm Hg/s, and dP/dtmin was -802 mm Hg/s. CONCLUSIONS: Hearts donated following euthanasia are highly valuable for research purposes and can have sufficient quality to be transplanted. With the implementation of ex situ heart perfusion, patients who are to donate their organs following euthanasia should also be able to donate their hearts. The complex combination of euthanasia and heart donation is ethically sound and surgically feasible and can contribute to shortening the heart transplant waiting list.

First experience with ex vivo lung perfusion for initially discarded donor lungs in the Netherlands: a single-centre study.

OBJECTIVES: Despite progress in lung transplantation (LTx) techniques, a shortage of donor lungs persists worldwide. Ex vivo lung perfusion (EVLP) is a technique that evaluates, optimizes and enables transplantation of the lungs that would otherwise have been discarded. Herein, we present our centre's first EVLP experiences between July 2012 and June 2016, when we performed 149 LTxs. METHODS: It was a single-centre, retrospective analysis of a prospectively collected database. The EVLP group (n = 9) consisted of recipients who initially received discarded donor lungs that were reconditioned using EVLP. The non-EVLP (N-EVLP) group (n = 18) consisted of data-matched patients receiving conventional quality lungs in the conventional way. Both groups were compared on primary graft dysfunction (PGD) grades 0-3, pulmonary function, chronic lung allograft dysfunction and survival. RESULTS: In the EVLP group, 33% (3/9) developed PGD1 at 72 h post-LTx. In the N-EVLP group, 11% (2/18) developed PGD1, 6% (1/18) PGD2 and 11% (2/18) PGD3 at 72 h post-LTx. At 3 and 24 months post-LTx, forced expiratory volume in 1 s as percentage of predicted was similar in the EVLP (78% and 92%) and N-EVLP groups (69% and 89%). Forced vital capacity as a percentage of predicted was comparable in the EVLP (77% and 93%) and N-EVLP groups (68% and 101%). Chronic lung allograft dysfunction was diagnosed in 1 N-EVLP patient at 2 years post-LTx. Three-year survival was 78% (7/9) (the EVLP group) vs 83% (15/18) (the N-EVLP group). CONCLUSIONS: These results are in line with the existing literature suggesting that transplantation of the previously discarded lungs recovered by EVLP leads to equal outcomes compared to conventional LTx methods.