Abstract
OBJECTIVES
Patients with mechanical circulatory support bridged to a heart transplant (HTx) are at higher risk of postoperative graft dysfunction. In this subset, a mode of graft preservation that shortens graft ischaemia should be beneficial.
Graphical Abstract.
METHODS
The outcomes of 38 patients on mechanical circulatory support (extracorporeal life support, left ventricular assist device and biventricular assist device) who received a HTx between 2015 and 2020 were analysed according to the method of graft preservation: cold storage (CS) group, 24 (63%) or ex vivo perfusion (EVP) group, 14 (37%).
RESULTS
The median age was 57 (range 30–73) vs 64 (35–75) years (P = 0.10); 88% were men (P = 0.28); extracorporeal life support was more frequent in the CS group (54% vs 36%; P = 0.27) versus left ventricular and biventricular assist devices in the EVP group (46% vs 64%; P = 0.27). Clamping time was shorter in the EVP group (P < 0.001) and ischaemic time >4 h was higher in the CS group (P = 0.01). Thirty-day mortality was 13% (0–27%) in the CS group and 0% (P = 0.28) in the EVP group. A significantly lower primary graft failure [7% (0–23%) vs 42% (20–63%); P = 0.03] was observed in the EVP group. Survival at 1 year was 79 ± 8% (63–95%) in the CS group and 84 ± 10% (64–104%) in the EVP group (P = 0.95).
CONCLUSIONS
Our results support the use of ex vivo graft perfusion in patients on mechanical circulatory support as a bridge to a HTx. This technique, by shortening graft ischaemic time, seems to improve post-HTx outcomes.
Keywords: Ex vivo perfusion, Heart transplantation, Mechanical circulatory support, Organ Care System
The purpose of mechanical circulatory support (MCS) as a bridge to a heart transplant (HTx) is to provide temporary haemodynamic stabilization in patients with advanced cardiac failure, allowing recovery of organ function; therefore, the use of MCS is growing worldwide, given the increasing need for HTx and the global donor shortage [1, 2].
INTRODUCTION
The purpose of mechanical circulatory support (MCS) as a bridge to a heart transplant (HTx) is to provide temporary haemodynamic stabilization in patients with advanced cardiac failure, allowing recovery of organ function; therefore, the use of MCS is growing worldwide, given the increasing need for HTx and the global donor shortage [1, 2]. However, the potential benefits of MCS may be counterbalanced by possible device-related complications due to the need for systemic anticoagulation or to a technically challenging chest re-entry at the time of the HTx. HTx in patients on MCS may result in prolonged cold ischaemic and bypass times, which may jeopardize the viability of the donor heart; thus, the risk of primary graft dysfunction (PGD) and subsequent associated complications, like nosocomial infection, multiorgan dysfunction and mortality, may be increased [3, 4].
Cold storage (CS), the traditional preservation technique for donor graft preservation, may be inadequate to avoid potential time-dependent ischaemic injuries to the graft. New technologies to prevent freezing and to monitor temperature represent attractive alternatives to traditional CS; however, even with such technologies, organ storage time is limited to 4 h [5].
A novel technique to protect the donor heart during extended periods of ischaemia is represented by ex vivo preservation (EVP) of the graft. EVP, maintaining the graft in a beating, physiological state, reduces the risk of ischaemic damage and allows timely identification of potentially unsuitable hearts through continuous evaluation of graft function. Such characteristics appear particularly important when dealing with marginal donors, because providing better protection for such grafts may significantly increase the pool of available donors [6]. Furthermore, EVP may also be effective for preserving grafts intended for high-risk recipients when prolonged ischaemic time is expected, such as those on MCS [7]. Because little information on this issue is currently available, we reviewed our experience to compare the results obtained with traditional CS and EVP in patients bridged to an HTx with either short- or long-term MCS.
METHODS
Study population
Of 128 consecutive patients having an HTx at our institution from January 2015 to June 2020, a total of 38 (30%) were bridged to HTx with MCS (Fig. 1): 18 (47%) had venoarterial extracorporeal membrane oxygenation (ECMO) (13 grafts were preserved with CS and 5 with EVP) whereas 20 (53%) had a left ventricular assist device (LVAD) or a biventricular assist device (BVAD) (11 grafts were preserved with CS and 9 with EVP). The major end point of the study, which was approved by our institutional review board, was assessment of the short-term outcomes following an HTx based on the 2 different techniques of donor graft preservation.
Figure 1:
Diagram of a heart transplant performed between 2015 and 2020. BVAD: biventricular assist device; ECMO: extracorporeal membrane oxygenation; LVAD: left ventricular assist device; MCS: mechanical circulatory support.
Surgical technique
Patients on extracorporeal membrane oxygenation
Venoarterial ECMO is instituted after surgical cannulation of femoral vessels maintaining distal leg perfusion. Our usual ECMO set-up comprises a centrifugal blood pump (Biomedicus BioPump, Medtronic, Minneapolis, MN, USA until 2010 and Rotaflow®, Maquet, Hirrlingen, Germany thereafter) with a hollow fibre oxygenator (Quadrox® by Maquet). Bioline® circuits (Maquet) coated with polypeptides and heparin to minimize anticoagulation requirements are utilized; systemic heparinization is adjusted to maintain an activated clotting time of 180–220 s. Left ventricular function is generally maintained with inotropic support and the use of an intra-aortic balloon pump, if necessary.
Patients with biventricular assist devices
All patients with BVAD were supported with a Berlin Heart Excor (Excor, Berlin Heart GmbH, Berlin, Germany), which comprises paracorporeal polyurethane blood pumps, pneumatically driven with trileaflet polyurethane valves. The Berlin Heart Excor cannulas are made of silicone rubber with an extremely smooth internal surface. Standard cannulation of the right heart is accomplished by drainage of the right atrium and ejection of the right pump blood volume into the pulmonary artery. On the left side, cannulation of either the left atrium or the left ventricular apex is possible. Pump outflow is conveyed to the ascending aorta. The Berlin Heart Excor is inserted through a full median sternotomy with the patient on cardiopulmonary bypass (CPB). Systemic heparinization is maintained until stability of oral anticoagulation is achieved, i.e. once an international normalized ratio of 2.0–3.0 has been reached.
Patients with left ventricular assist devices
LVADs were implanted through a midline sternotomy on a beating heart after initiation of CPB. The Jarvik-2000 (Jarvik Heart, Inc., New York, NY, USA) and the HeartWare (HeartWare Inc., Framingham, MA, USA) were the 2 LVAD models used. The Jarvik-2000 is a valveless, electrically powered axial-flow device that is inserted through the left ventricular apex and conveys the flow in the ascending aorta through its outflow. In comparison, the HeartWare uses centrifugal flow with an impeller that is suspended by a combination of magnetic and hydrodynamic forces. Even in this case, the inflow cannula is connected to the left ventricular apex and the outflow cannula, to the aorta.
The anticoagulation regimen is based on warfarin (with an international normalized ratio target of 1.8–2.2) for the Jarvik 2000 and a combination of low-dose of aspirin (100 mg/day) and warfarin (international normalized ratio target of 2.5–3.5) for the HeartWare.
Donor heart preservation
Donor grafts were preserved either with CS, which consists of St. Thomas cardioplegia infusion and CS in slushed ice, or with EVP using the Organ Care System (OCS) device (Transmedics Inc., Boston, MA. USA). The OCS method was described previously [6]; briefly, OCS is instituted by cannulating the aorta and pulmonary artery of the graft and connecting them through a circuit with an oxygenator and a pulsatile pump. The beating heart is perfused with warm, oxygenated, nutrient-enriched donor blood mixed with 1.2–1.5 l of priming solution. Graft function is assessed by continuous monitoring of aortic pressure, coronary flow and the differential lactate profile. A lactate level >5 mmol/l was considered a contraindication for using the graft. The OCS device was transported either by car, plane or helicopter, depending on the distance of the harvesting location.
The choice of the donor heart preservation technique was based on several factors, such as donor characteristics, logistics, the site of retrieval and OCS availability.
Heart transplant
Criteria for recipient selection and donor-recipient matching were based on standard guidelines [8, 9]. The HTx was performed using a bicaval technique. Immunosuppression therapy was standardized with steroids, cyclosporine A and mycophenolate mofetil. Our postoperative and long-term follow-up protocols were published previously and have remained unchanged during the study period [10, 11].
Definition of terms
PGD was defined according to the International Society for Heart and Lung Transplantation (ISHLT) guidelines and was considered relevant when the PGD was at grade ≥moderate and when the inotrope score was ≥10 [12]. Acute rejection was diagnosed, scored and treated according to ISHLT guidelines [13]. Grade ≥2 acute rejection was considered a post-Htx complication. Coronary allograft vasculopathy was diagnosed by angiography and defined according to the ISHLT classification [14]. Infections were considered any episode requiring antibiotic treatment.
Statistical analyses
Continuous variables are expressed as mean ± standard deviation or median and range according to the data distribution. The data were analysed using the Shapiro–Wilk test to verify the normal distribution. Categorical variables were presented as absolute numbers and percentages. The Student’s t-test or the Mann–Whitney U-test was used to compare continuous variables between groups, as appropriate. Comparison of categorical variables was performed by χ2 analysis or Fisher’s exact test, as appropriate. Overall survival was defined as freedom from all-cause mortality and was determined per the Kaplan–Meier approach. Comparisons between survival distributions were performed using the log-rank test. Analyses were performed with IBM SPSS Statistics 22 for Microsoft Windows (IBM Corp., Armonk, NY, USA).
RESULTS
Baseline characteristics
A total of 18 patients were bridged to an HTx after ECMO implantation. The median age was 61 years (range 30–75) and 17 (94%) were men. Twelve (67%) needed intra-aortic balloon pump support, 14 (78%), mechanical ventilation and 1 (6%), dialysis. Median support time on ECMO was 9 days (range 1–22). Conversely, 20 patients were bridged with LVAD or BVAD support. The median age was 56 years (range 35–65); 18 (90%) were men; and 1 (6%) was on dialysis. The median support time was 289 days (range 4–797), with 14 (70%) patients discharged home after the ventricular assist device implant. Six (30%) patients had a driveline infection.
Preoperative characteristics of the entire population based on the mode of graft preservation are summarized in Table 1. Dilated cardiomyopathy was the main cause of heart failure (63% vs 64%; P = 0.91), followed by ischaemic cardiomyopathy (13% vs 21%; P = 0.65), myocarditis (4% vs 7%; P = 1.00) and other (21% vs 7%; P = 0.38), in the CS and EVP groups, respectively. No significant difference was found in the pre-HTx characteristics of the 2 groups. Both echocardiographic data and laboratory values were comparable; particularly in the CS and EVP groups, differences in median LVEF [28% (10–74%) vs 20% (10–73%); P = 0.38], mean systolic pulmonary artery pressure (42 ± 15 vs 41 ± 10 mmHg; P = 0.98) and mean creatinine blood levels (1.5 ± 0.7 vs 1.3 ± 0.5 mg/dl; P = 0.35) were not significantly different.
Table 1:
Preoperative data
| CS (n = 24) | EVP (n = 14) | P-value | |
|---|---|---|---|
| Age (years), median (range) | 57 (30–73) | 64 (35–75) | 0.10 |
| Male, n (%) | 21 (88) | 14 (100) | 0.28 |
| Dilated cardiomyopathy, n (%) | 15 (63) | 9 (64) | 0.91 |
| Ischaemic cardiomyopathy, n (%) | 3 (13) | 3 (21) | 0.65 |
| Myocarditis, n (%) | 1 (4) | 1 (7) | 1.00 |
| Other, n (%) | 5 (21) | 1 (7) | 0.38 |
| Renal failure, n (%) | 7 (29) | 7 (50) | 0.20 |
| Previous PM/ICD implant, n (%) | 12 (50) | 8 (57) | 0.67 |
| Mechanical ventilation, n (%) | 11 (46) | 4 (29) | 0.33 |
| IABP, n (%) | 9 (38) | 5 (36) | 0.91 |
| ECMO, n (%) | 13 (54) | 5 (36) | 0.27 |
| LVAD/BVAD, n (%) | 11 (46) | 9 (64) | 0.27 |
| Support time (days), median (range) | 18 (7–797) | 65 (2–545) | 0.71 |
| Mean creatinine level (mg/dl), mean ± SD | 1.5 ± 0.7 | 1.3 ± 0.5 | 0.35 |
| LVEF (%), median (range) | 28 (10–74) | 20 (10–73) | 0.38 |
| PAP (mmHg), median (range) | 42 ± 15 | 41 ± 10 | 0.98 |
BVAD: biventricular assist device; CS: cold storage; ECMO: extracorporeal membrane oxygenator; EVP: ex vivo normothermic perfusion; ICD: implantable cardioverter defibrillator; LVAD: left ventricular assist device; LVEF: left ventricular ejection fraction; PAP: pulmonary artery pressure; PM: pacemaker.
Donor characteristics were similar in both groups (Table 2). Mean donor age was 44 ± 13 and 46 ± 11 years (P = 0.60) in the CS and EVP groups; 75% vs 79% (P = 1.00) were men. The median LVEF was 70% (50–75%) vs 59% (50–65%) (P = 0.29); 29% vs 36% (P = 0.68) had an episode of cardiac arrest and 4% vs 14% (P = 0.54) had a history of drug abuse.
Table 2:
Donor characteristics
| CS (n = 24) | EVP (n = 14) | P-value | |
|---|---|---|---|
| Age (years), mean ± SD | 44 ± 13 | 46 ± 11 | 0.60 |
| Age >55 years, n (%) | 4 (17) | 3 (21) | 1.00 |
| Men, n (%) | 18 (75) | 11 (79) | 1.00 |
| LVEF (%), median (range) | 70 (50–75) | 59 (50–65) | 0.29 |
| Cardiac arrest, n (%) | 7 (29) | 5 (36) | 0.68 |
| CAD, n (%) | 1 (4) | 0 | 1.00 |
| Drug abuse, n (%) | 1 (4) | 2 (14) | 0.54 |
| Distance of retrieval hospital (km), median (range) | 419 (0–1230) | 388 (184–1321) | 0.34 |
CAD: coronary artery disease; CS: cold storage; EVP: ex vivo perfusion; LVEF: left ventricular ejection fraction; SD: standard deviation.
Early outcomes
Graft ischaemic time was significantly lower in patients who had EVP (132 ± 28 vs 225 ± 48 min; P < 0.001). In 9 (38%) patients, grafts preserved with CS had an ischaemic time >4 h versus none of the EVP group (P = 0.01). Also, total CPB time was shorter in the EVP group [197 (126–236) vs 216 (154–310) min; P = 0.06], although the difference did not reach statistical significance. The total surgical time was similar (479 ± 127 vs 461 ± 113 min; P = 0.66) in both groups (Table 3) with lower reperfusion time (98 ± 40 vs 84 ± 21; P = 0.17) in the EVP group.
Table 3:
Postoperative data
| CS (n = 24) | EVP (n = 14) | P-value | |
|---|---|---|---|
| Ischaemic time (min), mean ± SD | 225 ± 48 | 132 ± 28 | <0.001 |
| Ischaemic time >4 h, n (%) | 9 (38) | 0 | 0.01 |
| CPB time (min), median (range) | 216 (154–310) | 197 (126–236) | 0.06 |
| EVP time (min), mean ± SD | 320 ± 76 | ||
| Reperfusion time (min), mean ± SD | 98 ± 40 | 84 ± 21 | 0.17 |
| Surgical time (min), mean ± SD | 479 ± 127 | 461 ± 113 | 0.66 |
| PGD grade ≥moderate, n (%) | 10 (42) | 1 (7) | 0.03 |
| Inotrope score >10, n (%) | 9 (39) | 1 (7) | 0.06 |
| ECMO, n (%) | 1 (4) | 0 | 1.00 |
| IABP, n (%) | 1 (4) | 1 (7) | 1.00 |
| Atrial fibrillation, n (%) | 2 (8) | 2 (14) | 0.62 |
| MV (h), median (range) | 72 (22–336) | 44 (10–432) | 0.61 |
| MV >72 h, n (%) | 9 (38) | 5 (36) | 0.91 |
| Bleeding, n (%) | 6 (25) | 5 (36) | 0.48 |
| Re-exploration for bleeding, n (%) | 4 (17) | 3 (21) | 1.00 |
| Infection, n (%) | 10 (42) | 9 (64) | 0.18 |
| AKI, n (%) | 8 (33) | 4 (29) | 1.00 |
| Need of CRRT, n (%) | 6 (25) | 3 (21) | 1.00 |
| Rejection grade >2, n (%) | 8 (33) | 5 (36) | 1.00 |
| Median ICU days (days) | 11 (2–70) | 8 (3–34) | 0.67 |
| Median hospital stay (days) | 40 (14–263) | 61 (21–110) | 0.14 |
| 30-Day mortality, n (%) | 3 (13) | 0 | 0.28 |
AKI: acute kidney injury; CPB: cardiopulmonary bypass; CRRT: continuous renal replacement therapy; CS: cold storage; ECMO: extracorporeal membrane oxygenator; EVP: ex vivo perfusion; IABP: intra-aortic balloon pump; ICU: intensive care unit; MV: mechanical ventilation; PGD: primary graft dysfunction; SD: standard deviation.
Early clinical outcomes post-HTx showed a significantly lower incidence of PGD grade ≥moderate [7% (0–23%) vs 42% (20–63); P = 0.03] in the EVP group. All those patients who experienced PGD were treated with inotropic support ≥10; 1 patient in each group needed intra-aortic balloon pump (4% vs 7%; P = 1.00), and 1 in the CS group needed ECMO (4% vs 0; P = 1.00). In the EVP group there were no hospital deaths, whereas 3 patients in the CS group died after the HTx [0% vs 13% (0–27); P = 0.28]; causes of early deaths were acute rejection, aortic dissection and multiple organ failure (Table 4).
Table 4:
Post-discharge complications according to the mode of graft protection
| CS (n = 19) | EVP (n = 12) | P-value | |
|---|---|---|---|
| Grade ≥2R rejection, n (%) | 8 (42) | 2 (17) | 0.24 |
| Neoplasia, n (%) | 2 (11) | 2 (17) | 0.63 |
| Infection, n (%) | 3 (16) | 3 (25) | 0.65 |
| CAV, n (%) | 2 (11) | 2 (17) | 0.63 |
CAV: coronary allograft vasculopathy; CS: cold storage; EVP: ex vivo perfusion.
The median hospital stay was 40 (14–263) days in the CS group and 61 (21–110) days in the EVP group (P = 0.14); EVP recipients experienced shorter duration of mechanical ventilation [44 (10–432) vs 72 (22–336) h; P = 0.61] and intensive care unit stay [11 (2–70) vs 8 (3–34) h; P = 0.67].
For patients on ECMO, the pre-HTx mean duration of CPB was significantly longer in those receiving a graft preserved with CS (204 ± 38 vs 161 ± 33 min; P = 0.04) as was the total mean ischaemic time (236 ± 34 vs 109 ± 5; P < 0.001); 30-day mortality was 7% (0–24%) vs 0% in those receiving a heart preserved with CS. Mean total surgical and aortic cross-clamp times were similar.
In patients bridged to HTx who were on LVAD/BVAD, the mean duration of CPB was similar whereas the total mean ischaemic time was significantly shorter in the EVP group (145 ± 26 vs 212 ± 61; P = 0.01); 30-day mortality was 18% (0–45%) vs 0% in the CS and EVP groups, respectively.
Follow-up data
The mean follow-up was 34 ± 24 months for the CS group and 23 ± 15 months (P = 0.10) for the EVP group. During the follow-up period, 6 patients died (3 in each group) of pancreatic neoplasia, cerebral haemorrhage and multiorgan failure in the CS group and of multiorgan failure, sepsis and ictus in the EVP group. The patients with EVP experienced a lower rate of ≥2 acute rejection episodes (17% vs 42%; P = 0.24), with a similar incidence of other complications. Survival at 1 year is 79 ± 8% (63–95%) in the CS group and 84 ± 10% (64–104%) in the EVP group (P = 0.95) (Fig. 2).
Figure 2:
Mid-term survival after a heart transplant, depending on the type of graft preservation. CS: cold storage; EVP: ex vivo perfusion.
DISCUSSION
The number of patients bridged to an HTx with MCS has increased dramatically in the past decade and now represents almost 50% of HTx candidates [1, 2]. MCS allows recovery of end-organ function and improves preoperative status and outcome in high-risk patients, thereby contributing significantly to reducing their mortality and morbidity while on the waiting list [15]. However, despite the benefits in stabilizing critically ill patients, MCS devices remain an important determinant of increased early morbidity and mortality after an HTx [3]. In particular, due to the prolonged cold ischaemic time of the graft, these procedures may be associated with a high risk of early graft dysfunction and related complications, leading to acute and chronic rejection, nosocomial infections, multiorgan dysfunction and eventually death [12].
The influence of preoperative MCS on the post-HTx course has been analysed previously, with several institutions reporting excellent survival of HTx recipients following MCS support [16–26]. Unfortunately, patient selection, type of device, duration of mechanical support, length of follow-up and other important parameters, including graft selection and preservation, were not uniform in these studies. Usually patients on ECMO who are bridged to an HTx have worse haemodynamic conditions, are often mechanically ventilated and more frequently have liver and renal impairment, sometimes exhibiting initial signs of local or systemic infection, whereas patients with LVAD and BVAD are in general more stable without organ dysfunction and most of them have been discharged home. On the other hand, an HTx in patients who are bridged with long-term LVAD or BVAD may be more complex and technically demanding, often requiring extensive, time-consuming tissue dissection to remove the devices and prolonged CPB times in the setting of an altered coagulation system; in such cases the outcome of these critical patients may depend on perfect timing and coordination between both HTx teams and on containment of graft ischaemic time. We have encountered such problems. Indeed, the patients in the present series bridged on ECMO were generally in a more critical condition. Considering that these 2 subsets of patients were quite different from a clinical point of view but had in common a similarly challenging HTx, the only parameter that can be effectively modified to improve their outcome is the length of time the donor graft is ischaemic, which has been demonstrated to be a significant variable impacting transplant results [9].
Because the effects of different strategies of graft perfusion, such as traditional CS and EVP, on the outcomes of patients bridged to HTx on short- and long-term MCS have not been adequately analysed, the goal of the present study was to investigate this issue.
EVP is a novel perfusion technology that provides an alternative to traditional CS: It maintains the donor graft in a normothermic beating state and allows constant assessment of the heart function during transportation [6–8]. An important advantage of EVP is the substantial reduction in total cold ischaemic time, which may result in maintaining favourable graft viability. As reported in this study, ischaemic time was significantly lower in the EVP than in the CS group (132 ± 28 vs 225 ± 48 min; P < 0.001), being in the CS group for >4 h in 40% of grafts. Total surgical times were similar (479 ± 127 vs 461 ± 113; P = 0.66), indicating that the use of EVP optimizes coordination between the HTx and the harvesting teams, thus allowing accurate, stress-free MCS removal and recipient preparation while the donor graft remains perfused. Limiting the ischaemic time should also contribute to reducing the risk of early complications as a direct consequence of graft ischaemia. In fact, García Sáez et al. [9] observed a lower incidence of right heart failure, improved allograft function, fewer blood transfusions and shorter intensive care unit and hospital stays in patients with MCS who received grafts maintained in EVP compared to those on CS. Besides, the ISHLT registry identified in a multivariate analysis that increased ischaemic time is a strong continuous risk factor for PGD [4]. Notably in our study, 1 patient in the EVP group had PGD, whereas 10 patients in the CS group developed this complication (P = 0.03) (Table 3).
Limitations
In addition to its retrospective nature and the absence of patient randomization, the main limitations of our study are the limited number of patients enrolled and the short follow-up time (maximum 66 months). Moreover, even if all enrolled patients are assisted with MCS, it must be recognized that ECMO, LVAD and BVAD represented nonhomogeneous groups because clinical conditions and haemodynamic stability were different; furthermore, as previously indicated, patients were also different from a surgical standpoint because those on LVAD or BVAD required more complex and risky procedures, at least for device removal.
We have also analysed our results based on the method of graft protection in each group with different MCSs; this analysis has substantially confirmed the results of the entire population although excessive data fragmentation has yielded less meaningful conclusions. Due to the paucity of data in the literature, we believe that the results of the present experience may still be considered an important starting point for stimulating further studies on this specific subject, including collecting data from larger patient populations and longer follow-up. The results of the present study demonstrated that patients on EVP receiving grafts sustained shorter ischaemic times regardless of the type of MCS, either ECMO or LVAD/BVAD, used to bridge patients to an HTx. Patients on EVP showed better early outcomes because fewer patients developed PGD [7% (0–23%) vs 42% (20–63%), P = 0.03] and all survived the HTx despite having a more technically demanding procedure compared to the CS group (P = 0.28). In our opinion, these findings support the use of EVP at least in specific subsets of high-risk recipients, such as those on MCS as a bridge to an HTx.
CONCLUSION
In conclusion, the use of EVP in patients with MCS was associated with better early outcomes compared to CS, most likely by allowing a reduction in ischaemic time in the donor heart, thus limiting cellular damage and immunological activation. Our results support the use of EVP during the harvesting of donor grafts reserved for patients in whom MCS have been implanted as a bridge to an HTx. This preliminary experience should also stimulate further studies to verify whether our data can be confirmed in larger patient populations and longer follow-up analyses.
Conflict of interest: none declared.
Author contributions
Sandro Sponga: Conceptualization; Writing—original draft. Giovanni Benedetti: Data curation. Nunzio Davide de Manna: Validation; Writing—review & editing. Veronica Ferrara: Data curation. Igor Vendramin: Data curation. Andrea Lechiancole: Data curation. Massimo Maiani: Data curation. Sandro Nalon: Software. Chiara Nalli: Conceptualization. Concetta Di Nora: Data curation. Uberto Bortolotti: Writing—review & editing. Ugolino Livi: Supervision.
Reviewer information
Interactive CardioVascular and Thoracic Surgery thanks Shinichiro Ikeda, David Kalfa, Suresh Keshavamurthy and the other, anonymous reviewer(s) for their contribution to the peer review process of this article.
Abbreviations
- BVAD
Biventricular assist device
- CPB
Cardiopulmonary bypass
- CS
Cold storage
- ECMO
Extracorporeal membrane oxygenation
- EVP
Ex vivo perfusion
- HTx
Heart transplant
- ISHLT
International Society for Heart and Lung Transplantation
- LVAD
Left ventricular assist device
- MCS
Mechanical circulatory support
- OCS
Organ Care System
Presented at the 33rd Annual Meeting of the European Association for Cardio-Thoracic Surgery, Lisbon, Portugal, 3–5 October 2019.
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