Transplant Library
567 results
Highlighted Expert Reviews
Liver Int. 2022 Nov;42(11):2513-2523 doi: 10.1111/liv.15396.
Transpl Infect Dis. 2022 Dec;24(6):e13979 doi: 10.1111/tid.13979.
Clin Transl Sci. 2022 Dec;15(12):2918-2927 doi: 10.1111/cts.13409.
  • Niikawa H
  • Okamoto T
  • Ayyat KS
  • Itoda Y
  • Sakanoue I
  • et al.
Artif Organs. 2022 Nov;46(11):2226-2233 doi: 10.1111/aor.14328.
CET Conclusion
Reviewer: Mr Simon Knight, Centre for Evidence in Transplantation, Nuffield Department of Surgical Sciences University of Oxford
Conclusion: The small experimental study randomised 10 double-lung blocks declined for transplant to either prone ex-vivo perfusion (EVLP) or supine EVLP. EVLP was continued for 2 hours, following which lung function, compliance and weight were assessed ex-vivo. The authors report that function was improved, and weight lower, in the prone group, with 3/5 lung blocks deemed suitable for transplant compared to none in the supine group. These findings are very interesting, but there are of course some limitations. Declined organs are likely to have different characteristics and a greater degree of variability in quality than those utilised for transplant, and in such a small sample there is the possibility of a type 1 error. As none of the lungs were transplanted, it is not clear whether the improvement in ex-vivo assessment would translate to improved clinical outcomes. However, the results do support further evaluation of prone EVLP in clinical studies of lungs intended for transplantation.
Study Details
Aims: This study aimed to assess whether prone positioning during EVLP was advantageous in human donor lungs declined for clinical transplant.
Interventions: Human double lung blocs were randomly assigned to either prone ex vivo lung perfusion (EVLP) or supine EVLP.
Participants: 10 human double lung blocs rejected for clinical transplant.
Outcomes: Lung function, compliance, weight and transplant suitability.
Follow Up: Following 2 hours of EVLP.
BACKGROUND:

We previously reported beneficial effects of prone positioning during ex vivo lung perfusion (EVLP) using porcine lungs. In this study, we sought to determine if prone positioning during EVLP was beneficial in human donor lungs rejected for clinical use.

METHODS:

Human double lung blocs were randomized to prone EVLP (n = 5) or supine EVLP (n = 5). Following 16 h of cold storage at 4°C and 2 h of cellular EVLP in either the prone or supine position. Lung function, compliance, and weight were evaluated and transplant suitability determined after 2 h of EVLP.

RESULTS:

Human lungs treated with prone EVLP had significantly higher partial pressure of oxygen/fraction of inspired oxygen (P/F) ratio [348 (291-402) vs. 199 (191-257) mm Hg, p = 0.022] and significantly lower lung weight [926(864-1078) vs. 1277(1029-1483) g, p = 0.037] after EVLP. 3/5 cases in the prone group were judged suitable for transplant after EVLP, while 0/5 cases in the supine group were suitable. When function of upper vs. lower lobes was evaluated, prone EVLP lungs showed similar P/F ratios and inflammatory cytokine levels in lower vs. upper lobes. In contrast, supine EVLP lungs showed significantly lower P/F ratios [68(59-150) vs. 467(407-515) mm Hg, p = 0.012] and higher tissue tumor necrosis factor alpha levels [100.5 (46.9-108.3) vs. 39.9 (17.0-61.0) ng/ml, p = 0.036] in lower vs. upper lobes.

CONCLUSIONS:

Prone lung positioning during EVLP may optimize the outcome of EVLP in human donor lungs, possibly by improving lower lobe function.

  • Schmucki K
  • Hofmann P
  • Fehr T
  • Inci I
  • Kohler M
  • et al.
Transplantation. 2023 Jan 1;107(1):53-73 doi: 10.1097/TP.0000000000004336.
BACKGROUND:

Chronic kidney disease (CKD) after lung transplantation is common and limits the survival of transplant recipients. The calcineurin inhibitors (CNI), cyclosporine A, and tacrolimus being the cornerstone of immunosuppression are key mediators of nephrotoxicity. The mammalian target of rapamycin (mTOR) inhibitors, sirolimus and everolimus, are increasingly used in combination with reduced CNI dosage after lung transplantation.

METHODS:

This systematic review examined the efficacy and safety of mTOR inhibitors after lung transplantation and explored their effect on kidney function.

RESULTS:

mTOR inhibitors are often introduced to preserve kidney function. Several clinical trials have demonstrated improved kidney function and efficacy of mTOR inhibitors. The potential for kidney function improvement and preservation increases with early initiation of mTOR inhibitors and low target levels for both mTOR inhibitors and CNI. No defined stage of CKD for mTOR inhibitor initiation exists, nor does severe CKD preclude the improvement of kidney function under mTOR inhibitors. Baseline proteinuria may negatively predict the preservation and improvement of kidney function. Discontinuation rates of mTOR inhibitors due to adverse effects increase with higher target levels.

CONCLUSIONS:

More evidence is needed to define the optimal immunosuppressive regimen incorporating mTOR inhibitors after lung transplantation. Not only the indication criteria for the introduction of mTOR inhibitors are needed, but also the best timing, target levels, and possibly discontinuation criteria must be defined more clearly. Current evidence supports the notion of nephroprotective potential under certain conditions.

  • Saliba F
  • Duvoux C
  • Dharancy S
  • Dumortier J
  • Calmus Y
  • et al.
Liver Int. 2022 Nov;42(11):2513-2523 doi: 10.1111/liv.15396.
CET Conclusion
Reviewer: Mr Simon Knight, Centre for Evidence in Transplantation, Nuffield Department of Surgical Sciences University of Oxford
Conclusion: In the original SIMCER study, liver transplant recipients were randomised to switch to everolimus and reduction and withdrawal of CNI within 6 months of liver transplant. The CERTUITUDE study (the observational follow-up study reported in this manuscript) optionally followed these patients for 5 -years to assess the impact of immunosuppression on long-term complications. 143 of 188 patients in the original study participated. By intent-to-treat analysis, there was no difference in renal function at month 60 between groups, with a higher incidence of treatment failure (acute rejection, death or graft loss) in the everolimus arm (30.8% vs 17.9%). Interestingly, incidence of malignancy was also numerically higher in the everolimus arm. The results are confounded by the fact that, as would be expected over 5 years, a large proportion of patients changed immunosuppressive regimen during the study. Per-protocol analysis demonstrates that renal function was better in the groups remaining on everolimus, and that risk of treatment failure was highest in patients switching from everolimus to tacrolimus during the study. Clearly an observational study of this nature is prone to some bias as treatment decisions were driven by clinicians outside of the original trial, losing the benefits of the initial randomisation. Nonetheless, long-term follow-up of this nature is useful to understand the natural evolution of immunosuppression choice and consequence.
Study Details
Aims: This study aimed to report the five-year outcomes of the CERTITUDE study, which was an observational follow-up study that included participants from the SIMCER study. The SIMCER study was a randomised controlled trial investigating the effect of everolimus and mycophenolic acid with early tacrolimus withdrawal in liver transplant recipients.
Interventions: Participants in the SIMCER trial were randomised to either receive everolimus with low-exposure tacrolimus discontinued by month 4 or to a conventional tacrolimus regimen, both with mycophenolic acid and the option of corticosteroid therapy.
Participants: 143 de novo liver transplant recipients from the SIMCER study.
Outcomes: The main outcomes of interest were renal function, cancers, treatment failure, major cardiovascular events (MACEs) and other safety parameters.
Follow Up: 5 years
BACKGROUND AND AIMS:

To report 5-year outcomes of the CERTITUDE study.

METHODS:

An observational study in patients with liver transplantation (LTx) compared the long-term impact of immunosuppression (with/without a calcineurin inhibitor) on renal function, cancers, major cardiovascular events (MACEs) and other safety parameters. All patients completing the 6-month SIMCER study were recruited and analysed according to treatment received at randomization and actual treatment received during the follow-up.

RESULTS:

Of the 143 enrolled patients, 119 completed the 5-year follow-up (everolimus [EVR], n = 55; tacrolimus [TAC], n = 64). The mean absolute change in estimated glomerular filtration rate was not statistically different between both groups (TAC, -15.53 ml/min/1.73 m2 and EVR, -14.56 ml/min/1.73 m2 ). In the treatment subgroups based on actual treatment received, renal function was preserved better in the EVR subgroup compared with other subgroups (p = .051). Treated biopsy-proven acute rejection was higher in the EVR group (15.4% vs. 6.4%); however, the majority of events were mild in severity. MACE occurred in 9.2% vs. 14.1% of patients in the EVR and TAC groups respectively (p = .370). De novo cancer was reported in 14 and 5 patients in EVR and TAC groups respectively. Hepatocellular carcinoma (HCC) recurrence was observed in the TAC group alone (n = 4). Adverse events and treatment discontinuation owing to an adverse event were higher in the EVR group.

CONCLUSIONS:

The CERTITUDE study demonstrated that EVR- and TAC-based regimens have comparable efficacy, safety and tolerability up to 5 years post-LTx.

  • Mugaanyi J
  • Dai L
  • Lu C
  • Mao S
  • Huang J
J Clin Med. 2022 Dec 28;12(1) doi: 10.3390/jcm12010235.
BACKGROUND:

The gap between the demand and supply of donor livers is still a considerable challenge. Since static cold storage is not sufficient in marginal livers, machine perfusion is being explored as an alternative. The objective of this study was to assess (dual) hypothermic oxygenated machine perfusion (HOPE/D-HOPE) and normothermic machine perfusion (NMP) in contrast to static cold storage (SCS).

METHODS:

Three databases were searched to identify studies about machine perfusion. Graft and patient survival and postoperative complications were evaluated using the random effects model.

RESULTS:

the incidence of biliary complications was lower in HOPE vs. SCS (OR: 0.59, 95% CI: 0.36-0.98, p = 0.04, I2: 0%). There was no significant difference in biliary complications between NMP and SCS (OR: 0.76, 95% CI: 0.41-1.40, p = 0.38, I2: 55%). Graft and patient survival were significantly better in HOPE than in SCS (HR: 0.40, 95% CI: 0.23-0.71, p = 0.002, I2: 0%) and (pooled HR: 0.43, 95% CI: 0.20-0.93, p = 0.03, I2: 0%). Graft and patient survival were not significantly different between NMP and SCS.

CONCLUSION:

HOPE/D-HOPE and NMP are promising alternatives to SCS for donor liver preservation. They may help address the widening gap between the demand for and availability of donor livers by enabling the rescue and transplantation of marginal livers.

  • Rinaldi M
  • Bonazzetti C
  • Gatti M
  • Caroccia N
  • Comai G
  • et al.
Transpl Infect Dis. 2022 Dec;24(6):e13979 doi: 10.1111/tid.13979.
CET Conclusion
Reviewer: Mr Simon Knight, Centre for Evidence in Transplantation, Nuffield Department of Surgical Sciences University of Oxford
Conclusion: This manuscript reports a systematic review and meta-analysis investigating the impact of positive perfusion fluid on risk of graft arteritis. Data from 21 observational studies are included, and the authors found that identification of high-risk pathogens in the perfusion fluid results in a significant increase in the odds of graft arteritis, especially fungal contamination. The review is very well conducted and reported, but perhaps slightly limited by the observational nature of the underlying studies. Risk of bias is high, and there is evidence of publication/reporting bias as might be expected in observational studies of this nature. Definitions of graft arteritis are unclear and not standardised. Nonetheless, routine culture of the preservation fluid is relatively inexpensive, and the results presented would support screening and consideration for prophylactic treatment of high-risk pathogens.
Study Details
Aims: The aim of this study was to examine the effect of positive preservation fluid (PF) on graft-site arteritis among solid organ transplant recipients.
Interventions: A literature search was performed on PubMed, MEDLINE, EMBASE, and Scopus databases. Study selection and data extraction were conducted independently by two pairs of authors. The methodological quality of the included studies was assessed using the the risk of bias in non-randomised studies of interventions (ROBINS-I) tool.
Participants: 21 studies were included in the review.
Outcomes: The main outcome of interest was graft arteritis development.
Follow Up: N/A
BACKGROUND:

The role of culturing the graft preservation fluid (PF) is controversial and its impact on graft arteritis development remains unclear.

METHODS:

Systematic literature search retrieving observational studies comparing solid organ transplant (SOT) recipients with culture-positive PF versus culture-negative PF. The quality of included studies was independently assessed according to the ROBINS-I tool for observational studies. Meta-analysis was performed using Mantel-Haenszel random-effect models. Graft site arteritis within 180 days from transplant was selected as the primary outcome.

RESULTS:

Twenty-one observational studies (N = 2208 positive PF vs. 4458 negative) were included. Among positive PF, 857 (38.8%) were classified as high-risk group pathogens and 1351 (61.2%) as low-risk pathogens. Low-risk and negative PF showed similar odds ratios. A significant higher risk of graft arteritis was found in SOT recipients with a PF yielding a high-risk pathogen (odds ratio [OR] 18.43, 95% confidence interval [CI] 7.83-43.40) compared to low-risk and negative PF, with low heterogeneity (I2 = 2.24%). Similar results were found considering separately high-risk bacteria (OR 12.02, 95%CI 4.88-29.60) and fungi (OR 71.00, 95%CI 28.07-179.56), with no heterogeneity (I2 = 0%), and in the subgroup analyses of the liver (OR 16.78, 95%CI 2.95-95.47) and kidney (OR 19.90, 95%CI 4.78-82.79) recipients. However, data about diagnostic features of graft arteritis were very limited, indeed for only 11 of the 93 events histological or microbiological results were reported.

CONCLUSIONS:

Our results may support the performance of PF culturing and a preemptive diagnostic or therapeutic management upon isolation of high-risk pathogens. Further studies based on a reliable diagnosis of graft arteritis are needed.

  • Minor T
  • von Horn C
  • Zlatev H
  • Saner F
  • Grawe M
  • et al.
Clin Transl Sci. 2022 Dec;15(12):2918-2927 doi: 10.1111/cts.13409.
CET Conclusion
Reviewer: Mr John O'Callaghan, Centre for Evidence in Transplantation, Nuffield Department of Surgical Sciences University of Oxford
Conclusion: This is a single centre feasibility study, albeit conducted in a randomised controlled methodology. It was designed to provide a foundation for a large, multicentre phase II study. However, this paper presents some very interesting and noteworthy information. The study was single-blinded, and outcomes were predominately objective. Extended criteria livers were included, in order to maximise the potential benefits. Randomisation was only done after the decision to transplant an included organ, and done using an independently-run, web-based system. Livers were randomised to standard care (static cold storage) or to the intervention of Controlled Oxygenated Re-warming (COR) using the Liver Assist (Organ Assist, The Netherlands). 40 livers were included (20 in each arm), and all received the intended therapy with no cross-overs or exclusions from analysis. The primary outcome was serum peak AST in the first 3 days. This was not statistically different between the 2 arms, despite a 45% lower mean peak for COR. COR was associated with a significant improvement in day 1 LiMAx test, factor 5 and bilirubin levels. There were no significant differences in INR, early allograft dysfunction or other secondary outcomes, such as ICU stay, hospital stay or 3 month graft survival. Taking steps forward from the experimental studies that underpin this trial, the current paper makes a very good case for a larger clinical trial in liver transplantation. The use of 60-minute COR in the transplant centre is logistically much less challenging than transporting perfusion devices to the retrieval site, and the continuous monitoring of a perfused liver in transit back.
Study Details
Aims: This study aimed to investigate whether reperfusion injury of cold stored liver grafts could be mitigated by controlled oxygenated rewarming using ex vivo machine perfusion prior to reperfusion.
Interventions: Participants were randomised to either the conventional static cold storage (SCS) group or the controlled oxygenated rewarming (COR) group.
Participants: 40 liver transplant recipients.
Outcomes: The primary outcome was serum peak value of aspartate aminotransferase (AST). The secondary outcomes included maximal liver function capacity, graft survival, early allograft dysfunction (EAD), intensive care unit (ICU) stay, and post-operative surgical complications.
Follow Up: 3 months

Abrupt return to normothermia has been shown a genuine factor contributing to graft dysfunction after transplantation. This study tested the concept to mitigate reperfusion injury of liver grafts by gentle warming-up using ex vivo machine perfusion prior to reperfusion. In a single center randomized controlled study, livers were assigned to conventional static cold storage (SCS) alone or to SCS followed by 90 min of ex vivo machine perfusion including controlled oxygenated rewarming (COR) by gentle and protracted elevation of the perfusate temperature from 10°C to 20°C. Primary outcome mean peak aspartate aminotransferase (AST) was 1371 U/L (SD 2871) after SCS versus 767 U/L (SD 1157) after COR (p = 0.273). Liver function test (LiMAx) on postoperative day 1 yielded 187 μg/kg/h (SD 121) after SCS, but rose to 294 μg/kg/h (SD 106) after COR (p = 0.006). Likewise, hepatic synthesis of coagulation factor V was significantly accelerated in the COR group immediately after transplantation (103% [SD 34] vs. 66% [SD 26]; p = 0.001). Fewer severe complications (Clavien-Dindo grade ≥3b) were reported in the COR group (8) than in the SCS group (15). Rewarming/reperfusion injury of liver grafts can be safely and effectively mitigated by controlling of the rewarming kinetics prior to blood reperfusion using end-ischemic ex vivo machine perfusion after cold storage.

  • Crocerossa F
  • Autorino R
  • Derweesh I
  • Carbonara U
  • Cantiello F
  • et al.
Minerva Urol Nephrol. 2023 Feb;75(1):1-16 doi: 10.23736/S2724-6051.22.04881-9.
INTRODUCTION:

After transplantation, approximately 10% of renal cell carcinomas are detected in graft kidneys. These tumors (gRCC) present surgeons with the difficulty of finding a treatment that guarantees both oncological clearance and maintenance of function. We conducted a systematic review and an individual patient data meta-analysis on the oncology, safety and functional outcomes of the available treatments for gRCC.

EVIDENCE ACQUISITION:

A systematic search was performed across MEDLINE, EMBASE, and Web of Science including any study reporting perioperative, functional and survival outcomes for patients undergoing graft nephrectomy (GN), partial nephrectomy (PN) or thermal ablation (TA) for gRCC. Quade's ANCOVA, Spearman Rho and Pearson χ2, Kaplan-Meier, Log-rank and Standard Cox regression and other tests were used to compare treatments. Studies' quality was evaluated using a modified version of Newcastle Ottawa Scale.

EVIDENCE SYNTHESIS:

A number of 29 studies (357 patients) were included. No differences between TA and PN were found in terms of safety, functional and oncological outcomes for T1a gRCCs. When applied to pT1b gRCC, PN showed no difference in complications, progression or cancer-specific deaths compared to smaller lesions; PN validity for pT2 gRCCs should be considered unverified due to lack of sufficient evidence. The efficacy and safety of PN or TA for multiple gRCC remain controversial. In case of non-functioning, large (T≥2), complicated or metastatic gRCCs, GN appears to be the most reasonable choice. Quality of evidence ranged from very low to moderate. Studies with large cohorts and longer follow-up are still needed to clarify oncological and functional differences.

CONCLUSIONS:

PN and TA might be offered as a nephron-sparing treatment in patients with T1a gRCC. There is no significant difference between these options and GN in terms of oncological outcomes and complications. PN and TA offer similar functional outcomes and graft preservation. PN for T1b gRCC seems feasible and safe, but its validity should be considered unverified.

  • Malinoski D
  • Saunders C
  • Swain S
  • Groat T
  • Wood PR
  • et al.
N Engl J Med. 2023 Feb 2;388(5):418-426 doi: 10.1056/NEJMoa2118265.
BACKGROUND:

Therapeutic hypothermia in brain-dead organ donors has been shown to reduce delayed graft function in kidney recipients after transplantation. Data are needed on the effect of hypothermia as compared with machine perfusion on outcomes after kidney transplantation.

METHODS:

At six organ-procurement facilities in the United States, we randomly assigned brain-dead kidney donors to undergo therapeutic hypothermia (hypothermia group), ex situ kidney hypothermic machine perfusion (machine-perfusion group), or both (combination-therapy group). The primary outcome was delayed graft function in the kidney transplant recipients (defined as the initiation of dialysis during the first 7 days after transplantation). We also evaluated whether hypothermia alone was noninferior to machine perfusion alone and whether the combination of both methods was superior to each of the individual therapies. Secondary outcomes included graft survival at 1 year after transplantation.

RESULTS:

From 725 enrolled donors, 1349 kidneys were transplanted: 359 kidneys in the hypothermia group, 511 in the machine-perfusion group, and 479 in the combined-therapy group. Delayed graft function occurred in 109 patients (30%) in the hypothermia group, in 99 patients (19%) in the machine-perfusion group, and in 103 patients (22%) in the combination-therapy group. Adjusted risk ratios for delayed graft function were 1.72 (95% confidence interval [CI], 1.35 to 2.17) for hypothermia as compared with machine perfusion, 1.57 (95% CI, 1.26 to 1.96) for hypothermia as compared with combination therapy, and 1.09 (95% CI, 0.85 to 1.40) for combination therapy as compared with machine perfusion. At 1 year, the frequency of graft survival was similar in the three groups. A total of 10 adverse events were reported, including cardiovascular instability in 9 donors and organ loss in 1 donor owing to perfusion malfunction.

CONCLUSIONS:

Among brain-dead organ donors, therapeutic hypothermia was inferior to machine perfusion of the kidney in reducing delayed graft function after transplantation. The combination of hypothermia and machine perfusion did not provide additional protection. (Funded by Arnold Ventures; ClinicalTrials.gov number, NCT02525510.).

  • Mohebbi N
  • Ritter A
  • Wiegand A
  • Graf N
  • Dahdal S
  • et al.
Lancet. 2023 Feb 18;401(10376):557-567 doi: 10.1016/S0140-6736(22)02606-X.
BACKGROUND:

Metabolic acidosis is common in kidney transplant recipients and is associated with declining graft function. Sodium bicarbonate treatment effectively corrects metabolic acidosis, but no prospective studies have examined its effect on graft function. Therefore, we aimed to test whether sodium bicarbonate treatment would preserve graft function and slow the progression of estimated glomerular filtration rate (GFR) decline in kidney transplant recipients.

METHODS:

The Preserve-Transplant Study was a multicentre, randomised, single-blind, placebo-controlled, phase 3 trial at three University Hospitals in Switzerland (Zurich, Bern, and Geneva), which recruited adult (aged ≥18 years) male and female long-term kidney transplant recipients if they had undergone transplantation more than 1 year ago. Key inclusion criteria were an estimated GFR between 15 mL/min per 1·73 m2 and 89 mL/min per 1·73 m2, stable allograft function in the last 6 months before study inclusion (<15% change in serum creatinine), and a serum bicarbonate of 22 mmol/L or less. We randomly assigned patients (1:1) to either oral sodium bicarbonate 1·5-4·5 g per day or matching placebo using web-based data management software. Randomisation was stratified by study centre and gender using a permuted block design to guarantee balanced allocation. We did multi-block randomisation with variable block sizes of two and four. Treatment duration was 2 years. Acid-resistant soft gelatine capsules of 500 mg sodium bicarbonate or matching 500 mg placebo capsules were given at an initial dose of 500 mg (if bodyweight was <70 kg) or 1000 mg (if bodyweight was ≥70 kg) three times daily. The primary endpoint was the estimated GFR slope over the 24-month treatment phase. The primary efficacy analyses were applied to a modified intention-to-treat population that comprised all randomly assigned participants who had a baseline visit. The safety population comprised all participants who received at least one dose of study drug. The trial is registered with ClinicalTrials.gov, NCT03102996.

FINDINGS:

Between June 12, 2017, and July 10, 2019, 1114 kidney transplant recipients with metabolic acidosis were assessed for trial eligibility. 872 patients were excluded and 242 were randomly assigned to the study groups (122 [50%] to the placebo group and 120 [50%] to the sodium bicarbonate group). After secondary exclusion of two patients, 240 patients were included in the intention-to-treat analysis. The calculated yearly estimated GFR slopes over the 2-year treatment period were a median -0·722 mL/min per 1·73 m2 (IQR -4·081 to 1·440) and mean -1·862 mL/min per 1·73 m2 (SD 6·344) per year in the placebo group versus median -1·413 mL/min per 1·73 m2 (IQR -4·503 to 1·139) and mean -1·830 mL/min per 1·73 m2 (SD 6·233) per year in the sodium bicarbonate group (Wilcoxon rank sum test p=0·51; Welch t-test p=0·97). The mean difference was 0·032 mL/min per 1·73 m2 per year (95% CI -1·644 to 1·707). There were no significant differences in estimated GFR slopes in a subgroup analysis and a sensitivity analysis confirmed the primary analysis. Although the estimated GFR slope did not show a significant difference between the treatment groups, treatment with sodium bicarbonate effectively corrected metabolic acidosis by increasing serum bicarbonate from 21·3 mmol/L (SD 2·6) to 23·0 mmol/L (2·7) and blood pH from 7·37 (SD 0·06) to 7·39 (0·04) over the 2-year treatment period. Adverse events and serious adverse events were similar in both groups. Three study participants died. In the placebo group, one (1%) patient died from acute respiratory distress syndrome due to SARS-CoV-2 and one (1%) from cardiac arrest after severe dehydration following diarrhoea with hypotension, acute kidney injury, and metabolic acidosis. In the sodium bicarbonate group, one (1%) patient had sudden cardiac death.

INTERPRETATION:

In adult kidney transplant recipients, correction of metabolic acidosis by treatment with sodium bicarbonate over 2 years did not affect the decline in estimated GFR. Thus, treatment with sodium bicarbonate should not be generally recommended to preserve estimated GFR (a surrogate marker for graft function) in kidney transplant recipients with chronic kidney disease who have metabolic acidosis.

FUNDING:

Swiss National Science Foundation.

  • Ravaioli M
  • Germinario G
  • Dajti G
  • Sessa M
  • Vasuri F
  • et al.
Am J Transplant. 2022 Oct;22(10):2401-2408 doi: 10.1111/ajt.17115.
CET Conclusion
Reviewer: Mr John O'Callaghan, Centre for Evidence in Transplantation, Nuffield Department of Surgical Sciences University of Oxford
Conclusion: This is an interesting and well-conducted trial in ECD liver transplantation. Livers were randomised to standard static cold storage (SCS) or to a period of Hypothermic Oxygenated Perfusion (HOPE), using the Vitasmart device (Bridge to Life, DG, USA). Organs in the HOPE group had a period of SCS of 4-5 hours on average prior to starting HOPE for 2-3 hours on average. No organ was discarded during perfusion. The study was single centre and designed with a prior power calculation to determine sample size. The primary endpoint was Early Allograft Dysfunction (EAD) using a well-established composite definition. There was a significant reduction in EAD with HOPE compared to SCS (13% versus 35%) and also a significant reduction in re-transplantation (0% versus 11%). This form of HOPE, using just portal vein perfusion in ECD liver transplantation, is associated with better early allograft function, which is very likely to impact on longer term function and graft survival.
Expert Review
Reviewer: Mr Simon Knight, Centre for Evidence in Transplantation, Nuffield Department of Surgical Sciences University of Oxford
Clinical Impact Rating 4
Review: The shortage of suitable donors to meet demand has resulted in increasing use of extended criteria donor (ECD) organs to try to address the mismatch. ECD donor organs are known to be more at risk of adverse post-operative outcomes due to increased vulnerability to ischaemia-reperfusion injury. In attempts to counter this additional risk, there has been a great deal of interest in novel perfusion technologies to recondition, repair and assess grafts prior to transplant. Such technologies can be used in the donor (normothermic regional perfusion, NRP) or ex-vivo (hypothermic oxygenated perfusion, HOPE or normothermic machine perfusion, NMP). The technologies differ in their simplicity/ease of use, ability to assess organ viability and the duration of safe perfusion. In a recent paper in the American Journal of Transplantation, Ravaioli and colleagues report a single centre randomised controlled trial of HOPE after static cold storage (SCS) versus SCS alone in ECD liver grafts (1). 110 recipients were randomised and followed for a median of 473 days. The authors report a significant reduction in the risk of the primary endpoint of early allograft dysfunction with HOPE, from 35% to 13%. This reduction is similar in magnitude to that seen in previous studies of NMP (2) and HOPE in DCD livers (3). Unlike in these previous studies there was no difference in incidence of biliary complications, most likely as this study does not include DCD livers which are at higher risk for ischaemic-type biliary lesions. Perhaps the most striking finding is that graft survival was significantly higher in the HOPE arm of the study, a finding not seen in the larger multicentre studies of HOPE or NMP. A detailed breakdown of causes and timings of graft loss is not provided, making the role of perfusion in this finding difficult to interpret. Another interesting finding is the numerically lower incidence of acute rejection in HOPE livers. This has been seen previously with use of HOPE in kidney transplantation (4), and may offer at least a partial explanation for the difference in graft survival seen. Overall, these findings support previous studies in both liver and kidney transplantation that HOPE is a safe, simple and effective method of preservation which may be beneficial in marginal donor organs. References 1. Ravaioli M, Germinario G, Dajti G et al. Hypothermic oxygenated perfusion in extended criteria donor liver transplantation-A randomized clinical trial. American Journal of Transplantation: Official Journal of the American Society of Transplantation and the American Society of Transplant Surgeons 2022; 2. Nasralla D, Coussios CC, Mergental H et al. A randomized trial of normothermic preservation in liver transplantation. Nature 2018; 557: 50. 3. van Rijn R, Schurink IJ, de Vries Y et al. Hypothermic Machine Perfusion in Liver Transplantation - A Randomized Trial. The New England Journal of Medicine 2021; 384: 1391. 4. Jochmans I, Brat A, Davies L et al. Oxygenated versus standard cold perfusion preservation in kidney transplantation (COMPARE): a randomised, double-blind, paired, phase 3 trial. Lancet (London, England) 2020; 396: 1653.
Study Details
Aims: The aim of this study was to compare the effect of hypothermic oxygenated perfusion (HOPE) versus static cold storage (SCS) in extended criteria donor (ECD) liver transplantation.
Interventions: Participants undergoing transplantation of an ECD liver graft were randomly assigned to receive a liver after HOPE or after SCS alone.
Participants: 135 potential ECD liver grafts were randomised, of which 110 were used for liver transplantation.
Outcomes: The primary outcome was the incidence of early allograft dysfunction (EAD). The secondary outcome were patient survival, graft survival, the early allograft failure simplified estimation (EASE) risk score, and the rate of graft or other graft-related complications.
Follow Up: 1 year

Hypothermic Oxygenated Perfusion (HOPE) of the liver can reduce the incidence of early allograft dysfunction (EAD) and failure in extended criteria donors (ECD) grafts, although data from prospective studies are very limited. In this monocentric, open-label study, from December 2018 to January 2021, 110 patients undergoing transplantation of an ECD liver graft were randomized to receive a liver after HOPE or after static cold storage (SCS) alone. The primary endpoint was the incidence of EAD. The secondary endpoints included graft and patient survival, the EASE risk score, and the rate of graft or other graft-related complications. Patients in the HOPE group had a significantly lower rate of EAD (13% vs. 35%, p = .007) and were more frequently allocated to the intermediate or higher risk group according to the EASE score (2% vs. 11%, p = .05). The survival analysis confirmed that patients in the HOPE group were associated with higher graft survival one year after LT (p = .03, log-rank test). In addition, patients in the SCS group had a higher re-admission and overall complication rate at six months, in particular cardio-vascular adverse events (p = .04 and p = .03, respectively). HOPE of ECD grafts compared to the traditional SCS preservation method is associated with lower dysfunction rates and better graft survival.