Heart Transplantation From DCD Donors in Australia: Lessons Learned From the First 74 Cases.

Heart transplantation from donation after circulatory death (DCD) donors has the potential to substantially increase overall heart transplant activity. The aim of this report is to review the first 8 y of our clinical heart transplant program at St Vincent's Hospital Sydney, to describe how our program has evolved and to report the impact that changes to our retrieval protocols have had on posttransplant outcomes. Since 2014, we have performed 74 DCD heart transplants from DCD donors utilizing a direct procurement protocol followed by normothermic machine perfusion. Changes to our retrieval protocol have resulted in a higher retrieval rate from DCD donors and fewer rejections of DCD hearts during normothermic machine perfusion. Compared with our previously reported early experience in the first 23 transplants, we have observed a significant reduction in the incidence of severe primary graft dysfunction from 35% (8/23) to 8% (4/51) in the subsequent 51 transplant recipients ( P < 0.01). The only withdrawal time interval significantly associated with severe primary graft dysfunction was the asystolic warm ischemic time: 15 (12-17) versus 13 (11-14) min ( P < 0.05). One- and 5-y survival of DCD heart transplant recipients was 94% and 88%, comparable to that of a contemporary cohort of donation after brain death recipients: 87 and 81% ( P -value was not significant). In conclusion, heart transplantation from DCD donors has become a major contributor to our overall transplant activity accounting for almost 30% of all transplants performed by our program in the last 2 y, with similar DCD and donation after brain death outcomes.

Cardiovascular Magnetic Resonance for Rejection Surveillance After Cardiac Transplantation.

BACKGROUND: Endomyocardial biopsy (EMB) is the gold standard method for surveillance of acute cardiac allograft rejection (ACAR) despite its invasive nature. Cardiovascular magnetic resonance (CMR)-based myocardial tissue characterization allows detection of myocarditis. The feasibility of CMR-based surveillance for ACAR-induced myocarditis in the first year after heart transplantation is currently undescribed. METHODS: CMR-based multiparametric mapping was initially assessed in a prospective cross-sectional fashion to establish agreement between CMR- and EMB-based ACAR and to determine CMR cutoff values between rejection grades. A prospective randomized noninferiority pilot study was then undertaken in adult orthotopic heart transplant recipients who were randomized at 4 weeks after orthotopic heart transplantation to either CMR- or EMB-based rejection surveillance. Clinical end points were assessed at 52 weeks. RESULTS: Four hundred one CMR studies and 354 EMB procedures were performed in 106 participants. Forty heart transplant recipients were randomized. CMR-based multiparametric assessment was highly reproducible and reliable at detecting ACAR (area under the curve, 0.92; sensitivity, 93%; specificity, 92%; negative predictive value, 99%) with greater specificity and negative predictive value than either T1 or T2 parametric CMR mapping alone. High-grade rejection occurred in similar numbers of patients in each randomized group (CMR, n=7; EMB, n=8; P=0.74). Despite similarities in immunosuppression requirements, kidney function, and mortality between groups, the rates of hospitalization (9 of 20 [45%] versus 18 of 20 [90%]; odds ratio, 0.091; P=0.006) and infection (7 of 20 [35%] versus 14 of 20 [70%]; odds ratio, 0.192; P=0,019) were lower in the CMR group. On 15 occasions (6%), patients who were randomized to the CMR arm underwent EMB for clarification or logistic reasons, representing a 94% reduction in the requirement for EMB-based surveillance. CONCLUSIONS: A noninvasive CMR-based surveillance strategy for ACAR in the first year after orthotopic heart transplantation is feasible compared with EMB-based surveillance. REGISTRATION: HREC/13/SVH/66 and HREC/17/SVH/80. AUSTRALIAN NEW ZEALAND CLINICAL TRIALS REGISTRY: ACTRN12618000672257.

Improved heart function from older donors using pharmacologic conditioning strategies.

BACKGROUND: Hearts from older donors are increasingly being referred for transplantation. However, these hearts are more susceptible to ischemia-reperfusion injury (IRI), reflected in higher rates of primary graft dysfunction. We assessed a strategy of pharmacologic conditioning, supplementing Celsior (Genzyme, Naarden, The Netherlands) preservation solution with glyceryl trinitrate (GTN; Hospira Australia Pty, Ltd, Mulgrave, VIC, Australia), erythropoietin (EPO; Eprex; Janssen-Cilag, North Ryde, NSW, Australia), and zoniporide (ZON; Pfizer, Inc., Groton, CT), to protect older hearts against IRI and improve graft function. METHODS: Wistar rats, aged 3, 12, and 18 months old, were used to represent adolescent, 30-year-old, and 45-year-old human donors, respectively. Animals were subjected to brain death (BD) and hearts stored for 6 hours at 2° to 3°C in Celsior or Celsior supplemented with GTN+EPO+ZON. Cardiac function and lactate dehydrogenase before and after storage were assessed during ex vivo perfusion. Western blots and histopathology were also analyzed. RESULTS: After BD, 18-month hearts demonstrated impaired aortic flow, coronary flow, and cardiac output compared with 3-month hearts (p < 0.001 to p < 0.0001). After storage in Celsior, the recovery of aortic flow, coronary flow, and cardiac output in 18-month BD hearts was further impaired (p < 0.01 vs 3-month hearts). Percentage functional recovery of 18-month BD hearts stored in Celsior supplemented with GTN+EPO+ZON was equivalent to that of 3-month hearts and significantly improved compared with 18-month hearts stored in Celsior alone (p < 0.01 to p < 0.001), with reduced lactate dehydrogenase release (p < 0.01) and myocardial edema (p < 0.05) and elevated phosphorylated extracellular signal-related kinase 1/2 (p < 0.05) and phosphorylated Akt (p < 0.01). CONCLUSIONS: Older hearts are more susceptible to IRI induced by BD and prolonged hypothermic storage. Supplemented Celsior activates cell survival signaling in older hearts, reduces IRI, and enhances donor heart preservation.

Enhanced preservation of the rat heart after prolonged hypothermic ischemia with erythropoietin-supplemented Celsior solution.

BACKGROUND: The cardioprotective efficacy of erythropoietin (EPO) has been widely documented in rodent models of acute coronary syndrome. We sought to evaluate its cardioprotective potential as an adjunct to Celsior cardioplegia in a rodent model of prolonged hypothermic global ischemia-reperfusion injury. METHODS: Isolated working rat hearts were subjected to 6 or 10 hours of hypothermic ischemic storage in Celsior cardioplegic solution. Celsior was supplemented with EPO over a dose range of 0 to 5 units/ml, as well as with glyceryl trinitrate (0.1 mg/ml) and zoniporide (1 µmol/liter). Myocardial functional recovery was determined after 45 minutes of reperfusion, then left ventricular tissue was prepared for Western blotting. RESULTS: The presence of EPO in Celsior dose-dependently improved recovery of myocardial function after 6 hours ischemic storage time (cardiac output recovery: 52.5 ± 11.3% vs 2.5 ± 0.4%; EPO: 5 units/ml vs 0 units/ml; p < 0.05). This functional benefit was associated with decreased lactate dehydrogenase released into coronary effluent and enhanced phosphorylation of STAT3, all of which were completely abrogated by pre-treatment with stattic, a selective inhibitor of STAT3 activation. When the ischemic storage time was extended to 10 hours, additive beneficial effects on myocardial function were seen when EPO was used in combination with the cardioprotective agents glyceryl trinitrate and zoniporide. CONCLUSIONS: EPO has demonstrated cardioprotective efficacy in a rodent model of ischemia-reperfusion injury simulating cardiac allograft preservation, which appears to be mediated via activation of the SAFE cytoprotective signaling pathway.