Preventing Delayed Graft Function in Kidney Transplant Patients

Background: A number of perioperative factors can impact graft function after kidney transplant, such as hypotension, type of intravenous fluid used, red blood cell transfusions and glycemic control. For example, we recently found that intraoperative hypotension was associated with DGF-CRR following kidney transplant, with a threshold mean arterial blood pressure of 65 mmHg (manuscript submitted). Furthermore, the odds of DGF-CRR increased when the MAP was < 75 mmHg. A method to manage blood pressure during kidney transplant is administering intravenous fluids, either with crystalloids or blood. A recent multicenter, randomized controlled trial showed that plasmalyte, a balanced crystalloid fluid, reduces the incidence of DGF-D after DD- kidney transplant by 25% (i.e. 40% to 30%) compared to normal saline. In the kidney transplant population, blood transfusion was reported to be associated with reduced graft function, early graft loss, and reduced patient survival. As the vast majority of patients receiving blood transfusion receive only 1-2 units, many transfusion events likely could be avoided with better adherence to appropriate triggers, potentially leading to improved outcomes following kidney transplant. Finally, irrespective of a pre-transplant diabetes diagnosis, hyperglycemia (blood sugar > 9.0 mmol/L) in the post-anesthesia care unit is associated with an increased odds of DGF-D following kidney transplant. Therefore, glucose control (i.e. blood sugar < 9 mmol/L) may improve immediate graft function in this patient population.

Rationale: Preserving graft function following kidney transplant is critical to ensuring favourable outcomes. We propose to study the application of a modified version of the KDIGO guidelines for kidney transplant patients. This perioperative bundle of care includes maintenance of MAP >75 mmHg after kidney reperfusion, use of plasmalyte for fluid administration, reducing red blood cell transfusion and identifying and treating a blood sugar > 9 mmol/L. Although this care bundle shows promise for reducing the risk of DGF following transplant, this should first be investigated in a pilot, feasibility trial to ensure successful patient recruitment and adherence to the study protocol, prior to undergoing a full RCT.

Hypothesis: We hypothesize that the proposed perioperative bundle of care will be feasible to implement and improve postoperative outcomes for kidney transplant recipients.

Primary Objectives: The primary objective is to determine the feasibility of recruiting and randomizing kidney transplant recipients to an RCT evaluating the administration of a perioperative bundle of care. Recruitment rate will be defined as the number of patients who are approached to participate in the study and who are randomized to either the treatment or routine clinical care group, as a percentage of the total number of eligible transplant patients. In order to complete a full multicenter trial in a reasonable time period (2-3 years), the number needed to recruit per week is at least 1 patient, but we will aim to recruit 2 patients per week.

The secondary objective is to determine protocol adherence and follow-up rates. The aim is for ≥90% compliance with at least 3 of the 4 components of the perioperative bundle of care i.e. use of Plasmalyte for fluid management, maintenance of MAP > 75 mmHg from time of cross-clamp removal to 4-hours post KT, the initiation of an insulin infusion to maintain a serum blood sugar < 9 mmol/L and avoidance of RBC transfusion unless the Hb < 70 g/L or symptoms of oxygen insufficiency and Hb < 80 g/L. For this trial, patient follow-up will end at 90-days after transplant and the target is to follow ≥90% of the patients until this time. DGF and acute rejection will not be assessed in the feasibility trial, and instead this data will be analyzed in the full trial. Patient follow-up of clinical outcomes will occur at 1-year following KT in the full trial.

Study Significance: This pilot study seeks to assess whether we can recruit kidney transplant patients for an RCT and assess compliance to a surgical care bundle aiming to reduce the incidence of delayed graft function. Preserving graft function after transplant is critical to ensuring favourable outcomes. The primary objectives of this study will assess protocol adherence and outcome collection rates. The results of this pilot trial will serve as the rationale to conduct a large, randomized controlled trial with the use of the surgical care bundle to enhance the recovery of kidney transplant patients.