Ex-Vivo Preservation with the Organ Care System in High Risk Heart Transplantation

Abstract

Objective: Ex vivo organ perfusion is an advanced preservation technique that allows graft assessment and extended ex situ intervals. We hypothesized that its properties might be especially beneficial for high-risk recipients and/or donors with extended criteria. Methods: We reviewed the outcomes of 119 consecutive heart transplant patients, which were divided into two groups: A (OCS) vs. B (conventional). Ex vivo organ perfusion was performed using the Organ Care System (OCS). Indications for OCS-usage were expected ischemic time of >4 h or >2 h plus given extended donor criteria. Results: Both groups included mostly redo cases (A: 89.7% vs. B: 78.4%; p = 0.121). Incidences of donors with previous cardiac arrest (%) (A: 32.4 vs. B: 22.2; p < 0.05) or LV-hypertrophy (%) (A: 19.1 vs. B: 8.3; p = 0.119) were also increased in Group A. Ex situ time (min) was significantly longer in Group A (A: 381 (74) vs. B: 228 (43); p < 0.05). Ventilation time (days) (A: 10.0 (19.9) vs. B: 24.3 (43.2); p = 0.057), postoperative need for ECLS (%) (A: 25.0 vs. B: 39.2; p = 0.112) and postoperative dialysis (chronic) (%) (A: 4.4 vs. B: 27.5; p < 0.001) were numerically better in the OCS group, without any difference in the occurrence of early graft rejection. The 30-d-survival (A: 92.4% vs. B: 90.2%; p = 0.745) and mid-term survival were statistically not different between both groups. Conclusions: OCS heart allowed safe transplantation of surgically complex recipients with excellent one-year outcomes, despite long preservation times and unfavourable donor characteristics. Furthermore, we observed trends towards decreased ventilation times and fewer ECLS treatments. In times of reduced organ availability and increasing recipient complexity, OCS heart is a valuable instrument that enables otherwise infeasible allocations and contributes to increase surgical safety.

The Tell-Tale Heart. Machine Perfusion in Heart Transplantation

“…Interestingly, in OCS group 4 hearts were discarded because of an increasing lactate concentration and histological analysis revealed signs of infarction and contusion and severe unrecognized left ventricular hypertrophy 13 . Other singlecenter and retrospective studies [14][15][16][17][18][19][20] further reported graft ischemic time significantly shorter when grafts were preserved with NMP instead of being preserved with SCS, as reported in Table I. Therefore, the OCS could be an effective tool to ensure graft quality when the expected ischemic exceed the traditional threshold of 4 hours, favoring long-distance organ retrieval.…”

“…Heart MP could also play a protective role in high-risk recipients, particularly in those supported by durable mechanical circulatory support or who have undergone previous complex operations 14,18,20 . HTx in these patients might be technically demanding and often require a tedious dissection and prolonged cardiopulmonary bypass times to complete the removal of intrathoracic ventricular assist devices or the isolation of the cardiac structures.…”

“…Donors with extended criteria were defined as those > 50 years of age, with a history of drug abuse, cardiac resuscitation, coronary artery disease (CAD), expected graft ischemia time > 4 hours, left ventricular ejection fraction (LVEF) < 50%, or interventricular septum thickness (IVS) > 14 mm. Data regarding marginal DBD donors are derived mainly from single-center observational studies 14,17,20 . A previous report of our group was able to demonstrate that NMP, compared to CS, seems to provide more stable hemodynamic conditions, reducing complications and allowing optimal outcomes.…”

Is the Organ Care System (OCS) Still the First Choice With Emerging New Strategies for Donation After Circulatory Death (DCD) in Heart Transplant?

“…The management of heart transplant recipients has substantially improved over the past few decades, but preservation and optimization of the graft have not received the attention they deserve. OCS can be a gamechanger since the longer preservation time not only gives us the flexibility to carry out complex recipient dissections and analyze and manage the donor graft before transplant but it can also increase the pool of possible donors [27]. Listed below are the major advantages of using the OCS system for heart procurement.…”

“…Therefore, organ transport time and time required for complex mediastinal dissection and reconstruction significantly increases the cold ischemia time of the donor's heart even after it reaches the recipient's operating room. The OCS system becomes a savior in these situations, and surgeons can perform more peaceful and conscious mediastinal dissection [27]. Fleck et al in their study found that pediatric transplant patients had better outcomes when the donor heart was perfused with OCS than those in which SCS was used [33].…”