The Impact of Intraoperative Diuretic Use on Delayed Graft Function Following Deceased Donor Renal Transplantation

Official title

A Pilot Randomized, Surgeon-blinded, Trial of Intraoperative Furosemide Versus Mannitol Among Deceased Donor Kidney Transplant Recipients

Overview

Delayed graft function, defined as the need for dialysis within seven days of kidney transplantation, is a common complication affecting deceased-donor kidney transplant recipients. It is associated with prolonged hospitalization, increased healthcare costs, higher rates of acute rejection, and poorer long-term graft survival. Intraoperative diuretics are routinely administered during kidney transplant surgery to promote early urine output and protect the kidney from injury during reperfusion. The two most commonly used agents are furosemide and mannitol. Despite decades of clinical use, no prospective randomized trial has directly compared these two medications, and practice remains highly variable across centres and individual surgeons. This single-centre, prospective, randomized, surgeon-blinded pilot trial will enroll 240 deceased-donor kidney transplant recipients at London Health Sciences Centre. Participants will be randomized in a 1:1 ratio, stratified by donor type, to receive either intraoperative furosemide or intraoperative mannitol. The primary feasibility outcomes include recruitment rate. The primary clinical outcome is the incidence of delayed graft function. Secondary outcomes include serum creatinine trajectory, urine output, dialysis requirements, perioperative complications, length of stay, and one-year graft and patient survival. This pilot trial will provide feasibility data and effect-size estimates necessary to inform the design of a future definitive multicentre randomized controlled trial.

Detailed description

Kidney transplantation has been the treatment of choice for end-stage renal disease for over six decades, yet delayed graft function (DGF) remains one of the most common and clinically significant complications of deceased-donor kidney transplantation. Defined as the requirement for at least one session of dialysis within the first seven days following transplantation, DGF affects 20-40% of deceased-donor kidney transplant recipients depending on the donor population and centre. DGF is associated with prolonged hospitalization, increased healthcare costs, a 1.4- to 2-fold increase in acute rejection risk, and inferior long-term graft survival. The pathophysiology centres on ischemia-reperfusion injury (IRI), which causes acute tubular necrosis, endothelial dysfunction, microvascular thrombosis, and upregulation of allograft immunogenicity through increased expression of MHC molecules and damage-associated molecular patterns. Donor type significantly influences DGF risk: donation after circulatory death (DCD) organs carry the highest historic rates due to sustained hypoperfusion and anaerobic metabolism during the agonal phase, while donation after neurological death (NDD) organs are affected by systemic inflammatory responses driven by loss of sympathetic regulation. Intraoperative diuretics, furosemide and mannitol, have been used for decades during reperfusion to enhance early urine output and mitigate IRI. Furosemide, a loop diuretic, inhibits the NKCC2 co-transporter in the thick ascending limb, reducing tubular metabolic oxygen demand, promoting tubular flushing, and stimulating renal prostaglandin-mediated vasodilation. Mannitol, an osmotic diuretic, maintains high tubular flow rates, reduces tubular cell swelling, acts as a hydroxyl radical scavenger, and promotes intrarenal vasodilation through prostaglandin and natriuretic peptide release. Despite these plausible mechanisms, the evidence supporting either agent remains weak. A comprehensive review by Sandal et al. (2018) found that the evidence supporting loop diuretics in preventing DGF was poor, with no data on patient survival identified. Schnuelle and van der Woude similarly concluded that loop diuretics had not been shown to affect DGF rates or improve outcomes. For mannitol, while van Valenberg et al. described its intraoperative use as "indispensable" based on early trial data, and a systematic review by van de Laar et al. (2021) suggested lower rates of DGF with mannitol use, that review emphasized significant limitations in evidence quality and heterogeneity. A randomized trial by Reiterer et al. evaluating mannitol versus placebo in 34 deceased-donor recipients found no significant effect on oxidation-reduction potential. A preclinical study by Bipat et al. demonstrated that mannitol preserved diuresis and creatinine clearance in a rabbit model of hypoxic kidneys, providing mechanistic support but not clinical confirmation. Current clinical practice is highly heterogeneous. A UK survey of 40 transplant surgeons from 18 centres revealed that 13 used no intraoperative diuretics, 10 used mannitol alone, 6 used furosemide alone, and 11 used a combination, underscoring the complete lack of consensus. A Canadian survey similarly demonstrated wide variation in practice patterns across transplant centres. Retrospective data from the investigators' centre suggest DGF rates of approximately 30% with furosemide and 22% with mannitol, but these non-randomized data preclude definitive conclusions. The existing literature is limited by small sample sizes, retrospective designs, inconsistent dosing protocols, heterogeneous patient populations, and the absence of standardized outcome definitions. No adequately powered, prospective, randomized trial has compared furosemide head-to-head against mannitol. Multiple reviews have concluded that well designed prospective randomized data are needed. This pilot trial addresses that evidence gap by providing the first direct, randomized, blinded comparison of these two agents with standardized dosing and timing, generating feasibility data, effect-size estimates, and operational infrastructure to support a future definitive multicentre trial.

Interventions

• Drug Furosemide
  Furosemide is a potent loop diuretic that inhibits the sodium-potassium-2-chloride (Na+/K+/2Cl-) co-transporter (NKCC2) on the luminal surface of the thick ascending limb of the loop of Henle. By blocking this transporter, furosemide reduces sodium reabsorption, increases sodium and water delivery to the distal nephron, and produces a brisk natriuresis and diuresis. In participants randomized to the Furosemide arm, 80 mg IV will be administered at 10-15 minutes prior to reperfusion of the transp
• Drug Mannitol
  Mannitol is a six-carbon sugar alcohol that is metabolically inert, freely filtered by the glomerulus, and largely unabsorbed by the renal tubules. It remains confined to the extracellular space and is excreted unchanged in the urine. As an osmotic diuretic, mannitol increases the osmolality of the glomerular filtrate, which opposes water reabsorption along the length of the nephron and produces dilute urine. In patients randomized to the Mannitol arm, mannitol 0.5 g/kg IV will be administered a

Primary outcome measures

• Recruitment rate [Time frame: From enrollment to the end of the study (1 year)]
• Consent Rate [Time frame: From enrollment to the end of the study (1 year).]
• Protocol Adherence [Time frame: From enrollment to end of study (1 year)]
• Data Completeness [Time frame: From enrollment to end of study (1 year)]
• Delayed Graft Function (DGF) [Time frame: From the administration of study drug until the end of post-op day 7.]

Secondary outcome measures (4)

• Early graft function [Time frame: From the time of enrollment up until post op day 7.]
• Postoperative dialysis requirement [Time frame: Post-op day 0 until the end of enrollment (1 year)]
• Post-operative Outcomes [Time frame: Post-op day 0 until the end of post-op day 30]
• Survival [Time frame: Post-op day 0 up until post-op day 365 (1 year post enrollment)]

Eligibility criteria

Inclusion criteria

• Age >18 years;
• Patient is scheduled to receive a deceased-donor kidney transplant (including both NDD and DCD donors)
• Patient is willing and able to provide written and informed consent, or a substitute decision maker (SDM) is available to sign on the patient's behalf

Exclusion criteria

• Patient is receiving another organ at the time of their kidney transplant (e.g., simultaneous kidney-pancreas or kidney-liver)
• Known allergy or contraindication to mannitol or furosemide
• Inability to provide informed consent
• Pediatric recipients (<18 years of age)
• Previously enrolled in this clinical trial

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Double blind

Primary purpose

Treatment

Study locations

Canada · 1 center

• London Health Sciences Centre — London

Publications

• Levine MA, Luke PP, Sener A. Canadian survey on the rates of use of intraoperative diuretics and justification for their use during renal allograft reperfusion. Can J Surg. 2020 Sep-Oct;63(5):E483-E488. doi: 10.1503/cjs.016019. PMID 33107815
• Reiterer C, Hu K, Sljivic S, Falkner von Sonnenburg M, Fleischmann E, Kabon B. The effect of mannitol on oxidation-reduction potential in patients undergoing deceased donor renal transplantation-A randomized controlled trial. Acta Anaesthesiol Scand. 2021 Feb;65(2):162-168. doi: 10.1111/aas.13713. Epub 2020 Oct 15. PMID 32966587
• van Valenberg PL, Hoitsma AJ, Tiggeler RG, Berden JH, van Lier HJ, Koene RA. Mannitol as an indispensable constituent of an intraoperative hydration protocol for the prevention of acute renal failure after renal cadaveric transplantation. Transplantation. 1987 Dec;44(6):784-8. doi: 10.1097/00007890-198712000-00012. PMID 3122381
• Bipat R, Steels P, Cuypers Y, Toelsie JR. Mannitol Reduces the Hydrostatic Pressure in the Proximal Tubule of the Isolated Blood-Perfused Rabbit Kidney during Hypoxic Stress and Improves Its Function. Nephron Extra. 2011 Jan;1(1):201-11. doi: 10.1159/000333478. Epub 2011 Nov 4. PMID 22470393
• Waskowski J, Pfortmueller CA, Erdoes G, Buehlmann R, Messmer AS, Luedi MM, Schmidli J, Schefold JC. Mannitol for the Prevention of Peri-Operative Acute Kidney Injury: A Systematic Review. Eur J Vasc Endovasc Surg. 2019 Jul;58(1):130-140. doi: 10.1016/j.ejvs.2019.02.003. Epub 2019 May 9. PMID 31078413
• Schnuelle P, Johannes van der Woude F. Perioperative fluid management in renal transplantation: a narrative review of the literature. Transpl Int. 2006 Dec;19(12):947-59. doi: 10.1111/j.1432-2277.2006.00356.x. PMID 17081224
• McMahon BA, Koyner JL, Novick T, Menez S, Moran RA, Lonze BE, Desai N, Alasfar S, Borja M, Merritt WT, Ariyo P, Chawla LS, Kraus E. The prognostic value of the furosemide stress test in predicting delayed graft function following deceased donor kidney transplantation. Biomarkers. 2018 Feb;23(1):61-69. doi: 10.1080/1354750X.2017.1387934. Epub 2017 Oct 16. PMID 29034718
• Sandal S, Bansal P, Cantarovich M. The evidence and rationale for the perioperative use of loop diuretics during kidney transplantation: A comprehensive review. Transplant Rev (Orlando). 2018 Apr;32(2):92-101. doi: 10.1016/j.trre.2017.11.002. Epub 2017 Nov 23. PMID 29242033

Identifiers

NCT: NCT07726134 · 16816 · AHSC AFP Innovation Fund

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗