Recipient hemodynamics during non-heart-beating donor kidney transplantation are major predictors of primary nonfunction

Intraoperative Mean Arterial Pressure and Postoperative Delayed Graft Function in Kidney Transplantation: Evaluating Three Commonly Used Thresholds

BACKGROUND

Delayed graft function (DGF) is a common early complication after kidney transplantation (KT) and is associated with various long-term adverse outcomes. Despite numerous studies on hemodynamic management, the optimal hemodynamic goals during KT remain unclear. In this retrospective study, we aimed to investigate if three mean artery pressure (MAP) thresholds (≤75, 80, and 85 mmHg) that were commonly used in clinical practice were associated with DGF in adult patients undergoing KT.

METHODS

We extracted de-identified data on adult patients who underwent deceased donor KT from our Discovery Data Repository. DGF was defined as the requirement for dialysis within the first 7 days after transplantation. Three MAP thresholds (≤75, 80, and 85 mmHg) and the duration of pressure below the three thresholds were recorded. Multivariable logistic analysis was used to identify risk factors for DGF.

RESULTS

We included 2301 adult KT patients. The mean age was 52.5±12.9 years and 59% were male. DGF occurred in 1066 patients (46.3%). Patients frequently experienced MAP ≤75, 80, and 85 mmHg (approximately 70%, 80%, and 90% of patients experienced 10 min of MAP ≤75, 80, and 85 mmHg, respectively). Patients with DGF spent significantly longer durations below the three MAP thresholds during surgery compared with those without DGF. Further analysis revealed that the minimal time spent on MAP ≤75, 80, and 85 mmHg that were significantly associated with DGF were 6, 23, and 37 min, respectively. After adjusting for non-hemodynamic risk factors (age, basiliximab administration, and urine output), prolonged exposure to the three MAP thresholds remained significant predictors for DGF (for MAP ≤75 mmHg, OR 1.257, 95% CI 1.017-1.554, p = 0.034; MAP ≤80 mmHg, OR 1.220, 95% CI 1.018-1.463, p = 0.031; MAP ≤85 mmHg, OR 1.253, 95% CI 1.048-1.498, p = 0.013).

CONCLUSION

Prolonged exposure to the three common MAP thresholds (≤75, 80, and 85 mmHg) occurred frequently during adult deceased donor KT and was associated with DGF.

Perioperative optic nerve sheath diameter variations in patients with end-stage renal failure undergoing robotic-assisted kidney transplant: a prospective observational study

Background

Patients with chronic kidney disease (CKD) who undergo hemodialysis are predisposed to interstitial cerebral edema. Robotic-assisted laparoscopic surgery can increase optic nerve sheath diameter (ONSD) and intracranial pressure. The impact of robotic-assisted kidney transplant (RAKT) on ONSD is complicated by the presence of CKD, the administration of furosemide and mannitol, and the manipulation of hemodynamics. We examined ONSD variations in patients undergoing RAKT over a 1-year period at our institution. Furthermore, we attempted to identify any perioperative hemodynamic factors influencing these changes.

Methods

This prospective study included 20 patients undergoing RAKT. ONSD, heart rate, central venous pressure, systolic blood pressure, diastolic blood pressure (DBP), and mean arterial pressure (MAP) were measured following intubation (T1), after assuming the steep Trendelenburg position (T2), 1 hour after docking (T3), upon reperfusion (T4), after transition to the supine position (T5), and 3 hours postextubation (T6). Repeated measures analysis of variance with post hoc Bonferroni correction was employed to compare variables at each time point. Pearson correlation analysis was utilized to assess relationships between variables. P-values ≤0.05 were considered to indicate statistical significance.

Results

ONSD (in mm) increased from T1 (3.60±0.44) to T3 (4.06±0.45, P=0.002) and T4 (3.99±0.62, P=0.046), before falling to its lowest value at T6 (3.42±0.64, P=0.002). Pearson correlation analysis revealed significant correlations (P<0.05) between changes in ONSD at T3 and both DBP (r=0.637) and MAP (r=0.522).

Conclusions

During RAKT with open ureteric anastomosis, ONSD initially increased, then decreased following reperfusion. DBP and MAP displayed positive correlations with ONSD changes at T3.

Intraoperative Hemodynamic Parameters Associated With Delayed Graft Function in Kidney Transplant Patients

PURPOSE

Intraoperative hemodynamic instability was proven to be associated with delayed graft function (DGF) after kidney transplantation. This retrospective study aims to find the specific intraoperative hemodynamic parameters as an efficient predicting factor of DGF.

MATERIALS AND METHODS

Patients who underwent kidney transplantation between 2020 and 2022 were enrolled and classified into DGF and non-DGF groups. Pediatric and multiorgan recipients were excluded. Hemodynamic parameters such as central venous pressure, mean arterial pressure, cardiac output, and cardiac index (CI) at the timings of wound incision, graft reperfusion, and operation completion were recorded, respectively. A comparison of parameters between these 2 groups was analyzed.

RESULTS

We enrolled 42 recipients, with 26 in the DGF group and 16 in the non-DGF group. Compared with the DGF group, CI around graft reperfusion was significantly higher in the non-DGF group (3.97 vs 4.67 L/min/m², P = .043). Other hemodynamic variables revealed no statistical difference. In the results of multivariate analysis, the deceased donor source, the greater volume of blood loss, and the lower CI around graft reperfusion were considered independent risk factors for DGF. Using CI around graft reperfusion to conduct a receiver operating characteristic (ROC) curve for DGF prediction, the area under the ROC curve achieved a value of 0.739 (95% confidence interval, 0.579-0.900), with the optimal cut-point value at CI = 4.245 L/min/m².

CONCLUSION

The cardiac index value around graft reperfusion was statistically associated with the incidence of DGF and might be used as a valid predicting factor.

Influence of Intraoperative Hemodynamic Parameters on Outcome in Simultaneous Pancreas-Kidney Transplant Recipients

Objectives: Adequate organ perfusion, as well as appropriate blood pressure levels at the time of unclamping, is crucial for early and long-term graft function and outcome in simultaneous pancreas−kidney transplantation (SPKT). However, the optimal intraoperative mean arterial pressure (MAP) level has not well been defined. Methods: From a prospectively collected database, the medical data of 105 patients undergoing SPKT at our center were retrospectively analyzed. A receiver operating characteristic (ROC) analysis was preliminarily performed for optimal cut-off value for MAP at reperfusion, to predict early pancreatic graft function. Due to these results, we divided the patients according to their MAP values at reperfusion into <91 mmHg (n = 47 patients) and >91 mmHg (n = 58 patients) groups. Clinicopathological characteristics and outcomes, as well as early graft function and long-term survival, were retrospectively analyzed. Results: Donor and recipient characteristics were comparable between both groups. Rates of postoperative complications were significantly higher in the <91 mmHg group than those in the >91 mmHg group (vascular thrombosis of the pancreas: 7 (14%) versus 2 (3%); p = 0.03; pancreatitis/intraabdominal abscess: 10 (21%) versus 4 (7%); p = 0.03; renal delayed graft function (DGF): 11 (23%) versus 5 (9%); p = 0.03; postreperfusion urine output: 106 ± 50 mL versus 195 ± 45 mL; p = 0.04). There were no significant differences in intraoperative volume repletion, central venous pressure (CVP), use of vasoactive inotropic agents, and the metabolic outcome. Five-year pancreas graft survival was significantly higher in the >91 mmHg group (>91 mmHg: 82% versus <91 mmHg: 61%; p < 0.01). No significant differences were observed in patient and kidney graft survival at 5 years between both groups. Multivariate Cox regression analysis affirmed MAP < 91 mmHg as an independent prognostic predictor for renal DGF (HR 3.49, 1.1−10.8, p = 0.03) and pancreas allograft failure (HR 2.26, 1.0−4.8, p = 0.01). Conclusions: A MAP > 91 mmHg at the time point of reperfusion was associated with a reduced rate of postoperative complications, enhancing and recovering long-term graft function and outcome and thus increasing long-term survival in SPKT recipients.

Balancing the tug of war: intraoperative and postoperative management of multiorgan transplantation

PURPOSE OF REVIEW

Multiorgan heart transplants (MOHT) have steadily increased and account for approximately 4% of all heart transplants performed. Although long-term outcomes of MOHT are similar to heart transplant alone, perioperative management remains an issue with nearly double the rate of prolonged hospitalization. Better understanding of hemodynamic environments encountered and appropriate therapeutic targets can help improve perioperative management.

RECENT FINDINGS

Accurate and precise hemodynamic monitoring allows for early identification of complications and prompt assessment of therapeutic interventions. This can be achieved with a multimodal approach using traditional monitoring tools, such a pulmonary artery catheter and arterial line in conjunction with transesophageal echocardiography. Specific targets for optimizing graft perfusion are determined by phase of surgery and organ combination. In some circumstances, the surgical sequence of transplant can help mitigate or avoid certain detrimental hemodynamic environments.

SUMMARY

With better understanding of the array of hemodynamic environments that can develop during MOHT, we can work to standardize hemodynamic targets and therapeutic interventions to optimize graft perfusion. Effectively navigating this perioperative course with multimodal monitoring including transesophageal echocardiography can mitigate impact of complications and reduce prolonged hospitalization associated with MOHT.

Crystalloid fluids and delayed graft function in kidney transplant: A cohort study

Background:

Normal saline is commonly used in the perioperative kidney transplant period; its high chloride content can cause hyperchloremic metabolic acidosis giving a possible advantage to balanced electrolyte solutions due to their lower chloride content. The evidence regarding the best practices in fluid management during kidney transplantation and its effect on the incidence of delayed graft function (DGF) is still limited.

Materials and Methods:

One hundred thirty-eight patients were included and followed up for seven days after surgery. Administered crystalloid type and volume were compared among patients with and without DGF, along with additional patient and surgical variables. To investigate whether intraoperative fluid type/amount influence DGF, patients were categorized into three groups: those who received mainly (>50%) lactated Ringer's solution, normal saline, or plasmaLyte. A logistic regression analysis was used to define variables independently correlated with DGF, and odds ratios (OR) with a 95% confidence interval (CI) were reported.

Results:

The incidence of DGF was 8.7%. Cold ischemia time independently increased the odds of DGF (OR = 1.006 (95% CI: 1.002–1.011) while fluid type (saline versus PlasmaLyte OR = 5.28, 95% CI: 0.76–36.88) or amount (OR = 1.00, 95% CI: 1.00–1.01) did not significantly modify the odds of DGF. Central venous pressure, systolic blood pressure, and mean arterial pressure were higher in the non-DGF group, but this was not statistically significant (P > 0.05). Significant intraoperative acidosis developed in patients who received normal saline compared to those in PlasmaLyte and lactated Ringer's groups; however, acid–base balance and electrolytes did not vary significantly between the DGF and non-DGF groups.

Conclusion:

DGF was primarily influenced by surgical factors such as cold ischemia time, whereas intraoperative fluid type or amount did not affect DGF incidence.

The effect of pulse pressure variation compared with central venous pressure on intraoperative fluid management during kidney transplant surgery: a randomized controlled trial

BACKGROUND

Traditionally, fluid administration during kidney transplant surgery is guided by central venous pressure (CVP) despite its limited reliability as a parameter for assessing intravascular fluid volume, particularly in patients with cardiovascular diseases. The recommended goals at graft reperfusion are a mean arterial pressure of 90 mm Hg and a CVP of 12-14 mm Hg. This approach may increase the risk of significant adverse effects due to volume overload. Perioperative fluid therapy guided by dynamic indices of fluid responsiveness has been shown to optimize intravascular volume and prevent complications associated with overzealous administration of fluids in major abdominal surgeries. We hypothesized that pulse pressure variation (PPV)-guided fluid administration would result in better optimization of intravascular fluid volume compared with a CVP-guided strategy during kidney transplant surgery.

METHODS

In this single-centre randomized double blinded trial, 77 end-stage renal disease patients, who underwent kidney transplant surgery under general anesthesia with epidural analgesia, were randomized to receive either CVP-guided (n = 35) or PPV-guided (n = 35) fluid therapy using predefined hemodynamic endpoints. The primary outcome was the total volume of intraoperative fluids administered. Secondary outcomes were intraoperative hemodynamic changes, serum lactate levels, serum creatinine, need for dialysis within the first week, creatinine elimination ratio, and incidence of immediate and delayed graft dysfunction.

RESULTS

Results were analyzed for 70 patients. Eighty percent of the patients underwent living-related donor allograft kidney transplant. Operative variables related to donor characteristics, duration of surgery, graft cold ischemia time, and blood loss were comparable in both groups. The mean (standard deviation) volume of intravenous fluids administered intraoperatively was 1,346 (337) mL in the PPV-guided group vs 1,901 (379) mL in the CVP-guided group (difference in means, 556 mL; 95% confidence interval, 385 to 727; P = 0.001). There were no significant differences in secondary outcomes between the two groups.

CONCLUSION

Pulse pressure variation -guided fluid administration significantly decreased the total volume of crystalloids compared with CVP-guided fluid therapy during the intraoperative period in patients who underwent kidney transplant surgery. Nevertheless, our study was underpowered to detect differences in secondary outcomes.

TRIAL REGISTRATION

www.ctri.nic.in (CTRI/2018/01/011638); registered 31 January 2018.

Fluid Management During Kidney Transplantation: A Consensus Statement of the Committee on Transplant Anesthesia of the American Society of Anesthesiologists

BACKGROUND

Intraoperative fluid management may affect the outcome after kidney transplantation. However, the amount and type of fluid administered, and monitoring techniques vary greatly between institutions and there are limited prospective randomized trials and meta-analyses to guide fluid management in kidney transplant recipients.

METHODS

Members of the American Society of Anesthesiologists (ASA) committee on transplantation reviewed the current literature on the amount and type of fluids (albumin, starches, 0.9% saline, and balanced crystalloid solutions) administered and the different monitors used to assess fluid status, resulting in this consensus statement with recommendations based on the best available evidence.

RESULTS

Review of the current literature suggests that starch solutions are associated with increased risk of renal injury in randomized trials and should be avoided in kidney donors and recipients. There is no evidence supporting the routine use of albumin solutions in kidney transplants. Balanced crystalloid solutions such as Lactated Ringer are associated with less acidosis and may lead to less hyperkalemia than 0.9% saline solutions. Central venous pressure is only weakly supported as a tool to assess fluid status.

CONCLUSIONS

These recommendations may be useful to anesthesiologists making fluid management decisions during kidney transplantation and facilitate future research on this topic.

Perioperative risk factors associated with delayed graft function following deceased donor kidney transplantation: A retrospective, single center study

BACKGROUND

There is an abundant need to increase the availability of deceased donor kidney transplantation (DDKT) to address the high incidence of kidney failure. Challenges exist in the utilization of higher risk donor organs into what appears to be increasingly complex recipients; thus the identification of modifiable risk factors associated with poor outcomes is paramount.

AIM

To identify risk factors associated with delayed graft function (DGF).

METHODS

Consecutive adults undergoing DDKT between January 2016 and July 2017 were identified with a study population of 294 patients. The primary outcome was the occurrence of DGF.

RESULTS

The incidence of DGF was 27%. Under logistic regression, eight independent risk factors for DGF were identified including recipient body mass index ≥ 30 kg/m², baseline mean arterial pressure < 110 mmHg, intraoperative phenylephrine administration, cold storage time ≥ 16 h, donation after cardiac death, donor history of coronary artery disease, donor terminal creatinine ≥ 1.9 mg/dL, and a hypothermic machine perfusion (HMP) pump resistance ≥ 0.23 mmHg/mL/min.

CONCLUSION

We delineate the association between DGF and recipient characteristics of pre-induction mean arterial pressure below 110 mmHg, metabolic syndrome, donor-specific risk factors, HMP pump parameters, and intraoperative use of phenylephrine.

Recipient pre-existing chronic hypotension is associated with delayed graft function and inferior graft survival in kidney transplantation from elderly donors

BACKGROUND

Pre-existing chronic hypotension affects a percentage of kidney transplanted patients (KTs). Although a relationship with delayed graft function (DGF) has been hypothesized, available data are still scarce and inconclusive.

METHODS

A monocentric retrospective observational study was performed on 1127 consecutive KTs from brain death donors over 11 years (2003-2013), classified according to their pre-transplant Mean Blood Pressure (MBP) as hypotensive (MBP < 80 mmHg) or normal-hypertensive (MBP ≥ 80 mmHg, with or without effective antihypertensive therapy).

RESULTS

Univariate analysis showed that a pre-existing hypotension is associated to DGF occurrence (p<0.01; OR for KTs with MBP < 80 mmHg, 4.5; 95% confidence interval [CI], 2.7 to 7.5). Chronic hypotension remained a major predictive factor for DGF development in the logistic regression model adjusted for all DGF determinants. Adjunctive evaluations on paired grafts performed in two different recipients (one hypotensive and the other one normal-hypertensive) confirmed this assumption. Although graft survival was only associated with DGF but not with chronic hypotension in the overall population, stratification according to donor age revealed that death-censored graft survival was significantly lower in hypotensive patients who received a KT from >50 years old donor.

CONCLUSIONS

Our findings suggest that pre-existing recipient hypotension, and the subsequent hypotension-related DGF, could be considered a significant detrimental factor, especially when elderly donors are involved in the transplant procedure.

Intravenous Fluid Management Practices in Kidney Transplant Patients: A Multicenter Observational Cohort Pilot Study

BACKGROUND

Limited evidence exists with regard to best practices in fluid management during kidney transplantation, which may directly affect the incidence of DGF. The authors of this study embarked on a collaborative observational multicenter pilot study to evaluate fluid administration practices in different transplant centers, with a focus on the relationship between total administered crystalloid volume and its association with DGF.

METHODS

Twenty consecutive kidney transplant patients were included from 9 academic medical centers in the United States. One hundred eighty patients were included in the final cohort and variables were compared between patients with and without DGF. Administered crystalloid volume was the primary variable of interest; however, additional patient and surgical variables were compared between patients with and without DGF. Variation in crystalloid administration was explored between centers by comparing median administered crystalloid volumes per kilogram of body weight. Also, unadjusted and adjusted logistic regression analyses were performed to determine which variables were independently associated with DGF.

RESULTS

Multivariable regression modeling demonstrated that cold ischemic time and ephedrine use during surgery were independently associated with DGF. There was no independent association between administered crystalloid volume and DGF.

CONCLUSION

In this study of patients having kidney transplantation, we did not find an independent association between administered crystalloid volume and DGF, although there was significant variability in crystalloid administration between centers. Our data suggest that DGF was driven mainly by surgical factors such as cold ischemic time. Ephedrine was also independently associated with DGF, which should be explored in future studies.

Intraoperative Fluid Restriction is Associated with Functional Delayed Graft Function in Living Donor Kidney Transplantation: A Retrospective Cohort Analysis

Background: In 2016 we observed a marked increase in functional delayed graft function (fDGF) in our living donor kidney transplantation (LDKT) recipients from 8.5% in 2014 and 8.8% in 2015 to 23.0% in 2016. This increase coincided with the introduction of a goal-directed fluid therapy (GDFT) protocol in our kidney transplant recipients. Hereupon, we changed our intraoperative fluid regimen to a fixed amount of 50 mL/kg body weight (BW) and questioned whether the intraoperative fluid regimen was related to this increase in fDGF. Methods: a retrospective cohort analysis of all donors and recipients in our LDKT program between January 2014–February 2017 (n = 275 pairs). Results: Univariate analysis detected various risk factors for fDGF. Dialysis dependent recipients were more likely to develop fDGF compared to pre-emptively transplanted patients (p < 0.001). Recipients developing fDGF received less intraoperative fluid (36 (25.9–50.0) mL/kg BW vs. 47 (37.3–55.6) mL/kg BW (p = 0.007)). The GDFT protocol resulted in a reduction of intraoperative fluid administration on average by 850 mL in total volume and 21% in mL/kg BW compared to our old protocol (p < 0.001). In the unadjusted analysis, a higher intraoperative fluid volume in mL/kg BW was associated with a lower risk for the developing fDGF (OR 0.967, CI (0.941–0.993)). After adjustment for the confounders, prior dialysis and the use of intraoperative noradrenaline, the relationship of fDGF with fluid volume was still apparent (OR 0.970, CI (0.943–0.998)). Conclusion: Implementation of a GDFT protocol led to reduced intraoperative fluid administration in the LDKT recipients. This intraoperative fluid restriction was associated with the development of fDGF.

Modifiable Risk Factors for Delayed Graft Function After Deceased Donor Kidney Transplantation

PURPOSE

Delayed graft function is a major complication after kidney transplantation affecting patients' long-term outcome. The aim of this study was to identify modifiable risk factors for delayed graft function after deceased donor kidney transplantation.

METHODS

This is a single-center retrospective cohort study of a university transplantation center. Univariate and multivariate step-wise logistic regression analysis of patient-specific and procedural risk factors were conducted.

RESULTS

We analyzed 380 deceased donor kidney transplantation patients between October 30, 2008 and December 30, 2017. The incidence of delayed graft function was 15% (58/380). Among the patient-specific risk factors recipient diabetes (2.8 [1.4-5.9] odds ratio [OR] [95% confidence interval [CI]]), American Society of Anesthesiologist score of 4 (2.7 [1.2-6.5] OR [95% CI]), cold ischemic time >13 hours (2.8 [1.5-5.3] OR [95% CI]) and donor age >55 years (1.9 [1.01-3.6] OR [95% CI]) revealed significance. The significant intraoperative, procedural risk factors included the use of colloids (3.9 [1.4-11.3] OR [95% CI]), albumin (3.0 [1.2-7.5] OR [95% CI]), crystalloids >3000 mL (3.1 [1.2-7.5] OR [95% CI]) and mean arterial pressure <80 mm Hg at the time of reperfusion (2.4 [1.2-4.8] OR [95% CI]).

CONCLUSION

Patients undergoing deceased donor kidney transplantation with a mean arterial pressure >80 mm Hg at the time of transplant reperfusion without requiring excessive fluid therapy in terms of colloids, albumin or crystalloids >3000 mL are less likely to develop delayed graft function.

Cardiac output-based fluid optimization for kidney transplant recipients: a proof-of-concept trial

PURPOSE

Intravenous fluid management for deceased donor kidney transplantation is an important, modifiable risk factor for delayed graft function (DGF). The primary objective of this study was to determine if goal-directed fluid therapy using esophageal Doppler monitoring (EDM) to optimize stroke volume (SV) would alter the amount of fluid given.

METHODS

This randomized, proof-of-concept trial enrolled 50 deceased donor renal transplant recipients. Data collected included patient characteristics, fluid administration, hemodynamics, and complications. The EDM was used to optimize SV in the EDM group. In the control group, fluid management followed the current standard of practice. The groups were compared for the primary outcome of total intraoperative fluid administered.

RESULTS

There was no difference in the mean (standard deviation) volume of intraoperative fluid administered to the 24 control and 26 EDM patients [2,307 (750) mL vs 2,675 (842) mL, respectively; mean difference, 368 mL; 95% confidence interval (CI), - 87 to + 823; P = 0.11]. The incidence of complications in the control and EDM groups was similar (15/24 vs 17/26, respectively; P = 0.99), as was the incidence of delayed graft failure (8/24 vs 11/26, respectively; P = 0.36).

CONCLUSIONS

Goal-directed fluid therapy did not alter the volume of fluid administered or the incidence of complications. This proof-of-concept trial provides needed data for conducting a larger trial to determine the influence of fluid therapy on the incidence in DGF in deceased donor kidney transplantation.

TRIAL REGISTRATION

www.clinicaltrials.gov (NCT02512731). Registered 31 July 2015.

Perioperative fluid management in kidney transplantation: a black box

The incidence of delayed graft function in patients undergoing kidney transplantation remains significant. Optimal fluid therapy has been shown to decrease delayed graft function after renal transplantation. Traditionally, the perioperative volume infusion regimen in this patient population has been guided by central venous pressure as an estimation of the patient’s volume status and mean arterial pressure, but this is based on sparse evidence from mostly retrospective observational studies. Excessive volume infusion to the point of no further fluid responsiveness can damage the endothelial glycocalyx and is no longer considered to be the best approach. However, achievement of adequate flow to maintain sufficient tissue perfusion without maximization of cardiac filling remains a challenge. Novel minimally invasive technologies seem to reliably assess volume responsiveness, heart function and perfusion adequacy. Prospective comparative clinical studies are required to better understand the use of dynamic analyses of flow parameters for adequate fluid management in kidney transplant recipients. We review perioperative fluid assessment techniques and discuss conventional and novel monitoring strategies in the kidney transplant recipient.

Perfusion of isolated rat kidney with Mesenchymal Stromal Cells/Extracellular Vesicles prevents ischaemic injury

Kidney donation after circulatory death (DCD) is a less than ideal option to meet organ shortages. Hypothermic machine perfusion (HMP) with Belzer solution (BS) improves the viability of DCD kidneys, although the graft clinical course remains critical. Mesenchymal stromal cells (MSC) promote tissue repair by releasing extracellular vesicles (EV). We evaluated whether delivering MSC-/MSC-derived EV during HMP protects rat DCD kidneys from ischaemic injury and investigated the underlying pathogenic mechanisms. Warm ischaemic isolated kidneys were cold-perfused (4 hrs) with BS, BS supplemented with MSC or EV. Renal damage was evaluated by histology and renal gene expression by microarray analysis, RT-PCR. Malondialdehyde, lactate, LDH, glucose and pyruvate were measured in the effluent fluid. MSC-/EV-treated kidneys showed significantly less global ischaemic damage. In the MSC/EV groups, there was up-regulation of three genes encoding enzymes known to improve cell energy metabolism and three genes encoding proteins involved in ion membrane transport. In the effluent fluid, lactate, LDH, MDA and glucose were significantly lower and pyruvate higher in MSC/EV kidneys as compared with BS, suggesting the larger use of energy substrates by MSC/EV kidneys. The addition of MSC/EV to BS during HMP protects the kidney from ischaemic injury by preserving the enzymatic machinery essential for cell viability and protects the kidney from reperfusion damage.

Delayed graft function and its management in children

Delayed graft function (DGF) is commonly defined as the requirement for dialysis within the first 7 days following renal transplantation. The major underlying mechanism is related to ischaemia/reperfusion injury, which includes microvascular inflammation and cell death and apoptosis, and to the regeneration processes. Several clinical factors related to donor, recipient and organ procurement/transplantation procedures may increase the risk of DGF, including donor cardiovascular instability, older donor age, donor creatinine concentration, long cold ischaemia time and marked body mass index of both the donor and recipient. Some of these parameters have been used in specific predictive formulas created to assess the risk of DGF. A variety of other pre-, intra- and post-transplant clinical factors may also increase the risk of DGF, such as potential drug nephrotoxicity, surgical problems and/or hyperimmunization of the recipient. DGF may decrease the long-term graft function, but data on this effect are inconsistent, partially due to the many different types of organ donation. Relevant management strategies may be classified into the classic clinical approach, which has the aim of minimizing the individual risk factors of DGF, and specific pharmacologic strategies, which are designed to prevent or treat ischaemia/reperfusion injury. Both strategies are currently being evaluated in clinical trials.

Hydrogen sulfide prevents renal ischemia-reperfusion injury in CLAWN miniature swine

BACKGROUND

Hydrogen sulfide (H₂S) has recently been reported to demonstrate both antiinflammatory and cytoprotective effects; however, its efficacy has not been well documented in large animal models. In this study, we examined whether the administration of H₂S offers cytoprotective effects on renal ischemia-reperfusion injury (IRI) in a preclinical miniature swine model.

METHODS

Major histocompatibility complex-inbred, CLAWN miniature swine (n = 9) underwent a right nephrectomy, followed by induction of a 120-min period of warm ischemia via placement of clamps on the left renal artery and vein. Group 1 (n = 3) underwent renal ischemia without H₂S administration. Groups 2 (n = 3) and 3 (n = 3) received Na₂S (prodrug of H₂S) 10 min before reperfusion of the ischemic kidneys followed by a 30-min of Na₂S postreperfusion intravenously (group 2) or selective administration of Na₂S via the left renal artery (group 3). IRI was assessed by kidney biopsies, levels of inflammatory cytokines in sera and kidney tissue.

RESULTS

Animals in group 1 had significantly higher serum creatinine levels compared with animals in groups 2 and 3 (P < 0.01). Histology showed severe tubular damage with TUNEL-positive cells in group 1 on postoperative day 2 compared with mild damage in group 2 and minimal damage in group 3. Furthermore, levels of inflammatory cytokines in both serum (interleukin-6 [IL-6], tumor necrosis factor-α, and high-mobility group box 1) and renal tissue (IL-1 and IL-6) in group 3 were markedly lower than in group 2, suggesting beneficial effects of selective Na₂S administration.

CONCLUSIONS

Na₂S administration, especially via an organ selective approach, appears to potentially offer cytoprotective and antiinflammatory effects following renal IRI.

Intraoperative Pleth Variability Index Is Linked to Delayed Graft Function After Kidney Transplantation

BACKGROUND

Delayed graft function (DGF) is an early postoperative complication of kidney transplantation (KT) predisposing to acute rejection and lower graft survival. Intraoperative arterial hypotension and hypovolemia are associated with DGF. Central venous pressure (CVP) is used to estimate volemia but its reliability has been criticized. Pleth variability index (PVI) is a hemodynamic parameter predicting fluid responsiveness. The aim of this study was to examine the relationship between intraoperative PVI and CVP values and the occurrence of DGF.

METHODS

This was a prospective, noninterventional, observational, single-center study. All consecutive patients with KT from deceased donors were included. Recipients received standard, CVP, and PVI monitoring. Intraoperative hemodynamic parameters were recorded from recipients at 5 time points during KT.

RESULTS

Forty patients were enrolled. There was a poor correlation between PVI and CVP values (r² = 0.003; P = .44). Immediate graft function and DGF patients had similar hemodynamic values during KT, with the exception of PVI values, which were significantly higher in the DGF group. In particular, a PVI >9% before unclamping of the renal artery was the only predictive parameter of DGF in our multivariate analysis (P = .02).

CONCLUSIONS

This study suggests that PVI values >9% during KT are associated with the occurrence of DGF.

Recommendations for donation after circulatory death kidney transplantation in Europe

Donation after circulatory death (DCD) donors provides an invaluable source for kidneys for transplantation. Over the last decade, we have observed a substantial increase in the number of DCD kidneys, particularly within Europe. We provide an overview of risk factors associated with DCD kidney function and survival and formulate recommendations from the sixth international conference on organ donation in Paris, for best-practice guidelines. A systematic review of the literature was performed using Ovid Medline, Embase and Cochrane databases. Topics are discussed, including donor selection, organ procurement, organ preservation, recipient selection and transplant management.

Delayed Graft Function in Kidney Transplants: Time Evolution, Role of Acute Rejection, Risk Factors, and Impact on Patient and Graft Outcome

Background. Although numerous risk factors for delayed graft function (DGF) have been identified, the role of ischemia-reperfusion injury and acute rejection episodes (ARE) occurring during the DGF period is ill-defined and DGF impact on patient and graft outcome remains controversial. Methods. From 1983 to 2014, 1784 kidney-only transplantations from deceased donors were studied. Classical risk factors for DGF along with two novel ones, recipient's perioperative saline loading and residual diuresis, were analyzed by logistic regression and receiver operating characteristic (ROC) curves. Results. Along with other risk factors, absence of perioperative saline loading increases acute rejection incidence (OR = 1.9 [1.2-2.9]). Moreover, we observed two novel risk factors for DGF: patient's residual diuresis ≤500 mL/d (OR = 2.3 [1.6-3.5]) and absence of perioperative saline loading (OR = 3.3 [2.0-5.4]). Area under the curve of the ROC curve (0.77 [0.74-0.81]) shows an excellent discriminant power of our model, irrespective of rejection. DGF does not influence patient survival (P = 0.54). However, graft survival is decreased only when rejection was associated with DGF (P < 0.001).  Conclusions. Perioperative saline loading efficiently prevents ischemia-reperfusion injury, which is the predominant factor inducing DGF. DGF per se has no influence on patient and graft outcome. Its incidence is currently close to 5% in our centre.

The feasibility and applications of non-invasive cardiac output monitoring, thromboelastography and transit-time flow measurement in living-related renal transplantation surgery: results of a prospective pilot observational study

Introduction

Delayed graft function (DGF) remains a significant and detrimental postoperative phenomenon following living-related renal allograft transplantation, with a published incidence of up to 15%. Early therapeutic vasodilatory interventions have been shown to improve DGF, and modifications to immunosuppressive regimens may subsequently lessen its impact. This pilot study assesses the potential applicability of perioperative non-invasive cardiac output monitoring (NICOM), transit-time flow monitoring (TTFM) of the transplant renal artery and pre-/perioperative thromboelastography (TEG) in the early prediction of DGF and perioperative complications.

Methods

Ten consecutive living-related renal allograft recipients were studied. Non-invasive cardiac output monitoring commenced immediately following induction of anaesthesia and was maintained throughout the perioperative period. Doppler-based TTFM was performed during natural haemostatic pauses in the transplant surgery: immediately following graft reperfusion and following ureteric implantation. Central venous blood sampling for TEG was performed following induction of anaesthesia and during abdominal closure.

Results

A single incidence of DGF was seen within the studied cohort and one intra-operative (thrombotic) complication noted. NICOM confirmed a predictable trend of increased cardiac index (CI) following allograft reperfusion (mean CI - clamped: 3.17 ± 0.29 L/min/m², post-reperfusion: 3.50 ± 0.35 L/min/m²; P < 0.05) mediated by a significant reduction in total peripheral resistance. Reduced TTFM at the point of allograft reperfusion (227 ml/min c.f. mean; 411 ml/min (95% CI: 358 to 465)) was identified in a subject who experienced intra-operative transplant renal artery thrombosis. TEG data exhibited significant reductions in clot lysis (LY30 (%): pre-op: 1.0 (0.29 to 1.71), post reperfusion 0.33 (0.15 to 0.80); P = 0.02) and a trend towards increased clot initiation following allograft reperfusion.

Conclusions

Reduced renal arterial blood flow (falling without the 95% CI of the mean), was able to accurately predict anastomotic complications within this pilot study. TEG data suggest the emergence of a prothrombotic state, of uncertain clinical significance, following allograft reperfusion. Abrogation of characteristic haemodynamic trends, as determined by NICOM, following allograft reperfusion may permit prediction of individuals at risk of DGF. The findings of this pilot study mandate a larger definitive trial to determine the clinical applications and predictive value of these technologies.

A proposal to grade the severity of early allograft dysfunction after liver transplantation

Objective:

To propose a grading system for early hepatic graft dysfunction.

Methods:

A retrospective study from a single transplant center. Recipients of liver transplants from deceased donors, transplanted under the MELD system were included. Early graft dysfunction was defined by Olthoff criteria. Multiple cut-off points of post-transplant laboratory tests were used to create a grading system for early graft dysfunction. The primary outcome was 6-months grafts survival.

Results:

The peak of aminotransferases during the first postoperative week correlated with graft loss. The recipients were divided into mild (aminotransferase peak >2,000IU/mL, but <3,000IU/mL); moderate (aminotransferase peak >3,000IU/mL); and severe (aminotransferase peak >3,000IU/mL + International Normalized Ratio ≥1.6 and/or bilirubin ≥ 10mg/dL in the 7^th postoperative day) early allograft dysfunction. Moderate and severe early dysfunctions were independent risk factors for graft loss. Patients with mild early dysfunction presented with graft and patient survival comparable to those without graft dysfunction. However, those with moderate early graft dysfunction showed worse graft survival than those who had no graft dysfunction. Patients with severe early dysfunction had graft and patient survival rates worse than those of any other groups.

Conclusion:

Early graft dysfunction can be graded by a simple and reliable criteria based on the peak of aminotransferases during the first postoperative week. The severity of the early graft dysfunction is an independent risk factor for allograft loss. Patients with moderate early dysfunction showed worsening of graft survival. Recipients with severe dysfunction had a significantly worse prognosis for graft and patient survival.

The value of machine perfusion biomarker concentration in DCD kidney transplantations

BACKGROUND

Donation after cardiac death (DCD) increases the number of donor kidneys but is associated with more primary nonfunction (PNF) and delayed graft function (DGF). It has been suggested that biomarkers in the preservation solution of machine perfused kidneys may predict PNF, although evidence is lacking.

METHODS

We analyzed the diagnostic accuracy of the perfusate biomarkers glutathione S-transferase, lactate dehydrogenase (LDH), heart-type fatty acid binding protein, redox-active iron, interleukin (IL)-18, and neutrophil gelatinase-associated lipocalin to predict PNF and DGF in 335 DCD kidneys preserved by hypothermic machine perfusion at our center between 1 January 1997 and 1 January 2008. The diagnostic accuracy of these biomarkers to predict PNF was evaluated with the area under the receiver operating characteristics curves. Additionally, the risk of DGF and graft failure was assessed.

RESULTS

LDH and IL-18 concentrations were associated with PNF (odds ratio [95% confidence interval], 1.001 [1.000-1.002]; P=0.005 and 1.001 [1.000-1.002]; P=0.003, respectively) in a multivariate analysis; the diagnostic accuracy for PNF was "poor" for all biomarkers but increased to "fair" for redox-active iron and IL-18 in a multivariate analysis (area under the receiver operating characteristics curves, 0.701 and 0.700, respectively). LDH and IL-18 concentrations were associated with DGF; biomarker concentration was not associated with 1-year graft survival.

CONCLUSIONS

The diagnostic accuracy of the perfusate biomarkers glutathione S-transferase, LDH, heart-type fatty acid binding protein, redox-active iron, IL-18, and neutrophil gelatinase-associated lipocalin to predict viability of DCD kidneys varies from "poor" to "fair". Therefore, DCD kidneys should not be discarded because of high biomarker perfusate concentration.

Do intraoperative hemodynamic factors of the recipient influence renal graft function?

PURPOSE

To assess the importance of intraoperative management of recipient hemodynamics for immediate versus delayed graft function.

METHODS

The retrospective study of 1966 consecutive renal transplants performed in our department between June 1980 and December 2009 analyzed several perioperative hemodynamic factors: central venous pressure (CVP), mean arterial pressure (MAP) as well as volumes of fluids, fresh frozen plasma (FFP), albumin, and whole blood transfusions. We examined their influence on renal graft function parameters: immediate diuresis, serum creatinine levels, acute rejection, chronic transplant dysfunction, and graft survival.

RESULTS

Mean CVP was 9.23 ± 2.65 mm Hg and its variations showed no impact on graft function. We verified a twofold greater risk of chronic allograft dysfunction among patients with CVP ≥ 11 mm Hg (P < .001). Mean MAP was 93.74 ± 13.6 mm Hg; graft survivals among subjects with MAP ≥ 93 mm Hg were greater than those of patients with MAP < 93 mm Hg (P = .04). On average, 2303.6 ± 957.4 mL of saline solutions were infused during surgery. Patients who received whole blood transfusions (48%) showed a greater incidence of acute rejection episodes (ARE) (P = .049) and chronic graft dysfunction (P < .001). Patients who received FFP (55.7%), showed a higher incidence of ARE (P < .001). Only 4.6% of patients (n = 91) received human albumin with a lower incidence of ARE (P = .045) and chronic graft dysfunction (P = .024). Logistic binary regression analysis revealed that plasma administration was an independent risk factor for ARE (P < .001) and chronic dysfunction (P = .028). Volume administration (≥ 2500 mL) was also an independent risk factor for chronic allograft dysfunction (P = .016). Using Cox regression, we verified volume administration ≥ 2500 mL to be the only independent risk factor for graft failure (P < .001).

CONCLUSION

MAP ≥ 93 mm Hg and perioperative fluid administration <2500 mL were associated with greater graft survival. Albumin infusion seemed to be a protective factor, while CVP ≥ 11 mm Hg, whole blood, and FFP transfusions were associated with higher rates of ARE and chronic graft dysfunction.

Delayed graft function in the kidney transplant

Acute kidney injury occurs with kidney transplantation and too frequently progresses to the clinical diagnosis of delayed graft function (DGF). Poor kidney function in the first week of graft life is detrimental to the longevity of the allograft. Challenges to understand the root cause of DGF include several pathologic contributors derived from the donor (ischemic injury, inflammatory signaling) and recipient (reperfusion injury, the innate immune response and the adaptive immune response). Progressive demand for renal allografts has generated new organ categories that continue to carry high risk for DGF for deceased donor organ transplantation. New therapies seek to subdue the inflammatory response in organs with high likelihood to benefit from intervention. Future success in suppressing the development of DGF will require a concerted effort to anticipate and treat tissue injury throughout the arc of the transplantation process.

Predicting donor asystole following withdrawal of treatment in donation after cardiac death

Donation after cardiac death donation allows donor pool expansion. The period between withdrawal of treatment and donor a systole is extremely variable; its prolongation often results in unsuccessful organ procurement. We sought to assess a variety of donor variables to determine whether they predicted successful organ retrieval. We included all Donation after Cardiac Death (DCD) retrievals between 2002 and 2009, which were grouped as successful (n = 104) versus unsuccessful (n = 42). Factors that predicted unsuccessful organ procurement included older donor age, donor history of hypertension, higher at withdrawal, and absence of inotropic support. On multivariate analysis, mean arterial pressure retained its significance. Prediction of withdrawal-to-asystole time is complex, but our analysis suggested that donor blood pressure at withdrawal is an important predictor of whether retrieval would be successful.

Renal transplantation following donation after cardiac death: impact of duration from withdrawal to asystole

Donation after cardiac death (DCD) allows for expansion of the donor pool, however, the process for DCD donation can lead to a donor's physiological instability before asystole. This may have a detrimental effect on graft and patient outcomes. We analyzed all 201 DCD donations at our unit from 2002 to 2009 and compared short versus long durations to asystole around the median time (20 min). Delayed graft function was comparable between the groups (P = .13), primary nonfunction was increased in the long duration to asystole group (P < .0001), and acute rejection was increased in the short duration group (P < .001). Five year patient survival was comparable (P = .6). In conclusion, long duration asystole may have an immediate effect on graft survival, but it has no overall detrimental effect on longer-term outcomes. Further studies are required to investigate the acceptable time to wait from withdrawal to asystole.

Kidney transplantation from donors after cardiac death: a 25-year experience

BACKGROUND

The shortage of organ donors presents a major obstacle for adequate treatment of patients with end-stage renal disease. Donation after cardiac death (DCD) has been shown to increase the number of kidneys available for transplantation. The present article reports on the first 25 years of our experience with DCD kidney transplantation.

METHODS

This observational cohort study included all DCD kidney transplantations recovered in our procurement area from January 1, 1981 until December 31, 2005 (n=297). Patients were followed up until the earliest of death or December 31, 2006. Clinical outcomes were compared with matched kidney transplantations from brain dead donors (DBD, n=594), using multivariable regression models to adjust for potential confounders.

RESULTS

DCD activity resulted in a 44% increase in the number of deceased donor kidneys from our organ procurement area. After adjustment for potential confounders, the odds of primary nonfunction and delayed graft function were 7.5 (95% CI, 4.0-14.1; P<0.001) and 10.3 (95% CI, 6.7-15.9; P<0.001) times greater, respectively, for DCD kidneys compared with DBD kidneys. The high incidence of primary nonfunction of DCD kidneys resulted in an increased rate of graft loss (HR, 1.82; 95% CI, 1.37-2.42; P<0.001). However, DCD kidneys that did not experience primary nonfunction functioned as long as DBD kidneys (HR, 1.05; 95% CI, 0.73-1.51; P=0.79). Patient survival of DCD and DBD kidney recipients was equivalent (HR, 1.16; 95% CI, 0.87-1.54; P=0.32).

CONCLUSIONS

The benefits of DCD kidney transplantation outweigh the increased risk of early graft loss. Expansion of the supply of DCD kidneys is likely to improve the treatment of wait-listed dialysis patients.

Autologous transplantation of ischemically injured kidneys in pigs

BACKGROUND

Expansion of the organ donor pool can be obtained through novel interventions attenuating ischemic acute kidney injury, which will enable the use of kidneys that suffered prolonged ischemia. In basic science, new therapeutic targets are identified that should be tested in a relevant large animal model before use in human kidney transplantation.

MATERIALS AND METHODS

The current paper provides a detailed description of the technique of autologous transplantation of ischemically injured kidneys in pigs with special emphasis on perioperative care.

RESULTS

The animal model was validated by showing that renal function after transplantation was proportional to the duration of warm ischemia before organ recovery. The extent of renal dysfunction was reproducible following kidney transplantations with the same warm ischemia time.

CONCLUSIONS

Our experience may reduce the learning curves of other research groups taking an interest in the model and improve preclinical testing of novel interventions that modulate renal ischemia and reperfusion injury in kidney transplantation.

Acceptable outcome after kidney transplantation using "expanded criteria donor" grafts

INTRODUCTION

With the worldwide shortage of donors, extra lengths are ongoing to enlarge the donor pool. One means has been a greater use of "expanded criteria donor" (ECD) grafts. A major concern regarding ECD kidneys is poor long-term graft survival. The aims of this study were to determine whether ECD grafts, as defined by the United Network for Organ Sharing, had a negative impact on graft survival and to identify the principle donor and recipient factors that influenced graft survival in our patient cohort.

METHODS

We analyzed all deceased donor renal transplants in our unit from January 1995 to October 2005, in total 1,053 transplants.

RESULTS

ECD grafts (United Network for Organ Sharing criteria) demonstrated higher rates of delayed graft function and higher early mean creatinine levels. However, there was no significant difference in 5-year graft survival. Multivariate analysis of our patient group identified donor hypertension and ischemic heart disease (IHD) as independent predictors of poor graft survival. Recipient age was significant on univariate but not on multivariate analysis. However, although younger recipients maintained acceptable 5-year graft survival despite donor hypertension, IHD, or a combination of both, these factors significantly reduced graft survival in older recipients.

CONCLUSION

Although ECD grafts had slightly worse function, 5-year survival was comparable with standard grafts in all recipients. Donor hypertension, IHD, or a combination of both significantly reduced graft survival in older recipients, not evident in younger patients. We discuss the possible factors for improved outcome with ECD grafts in our patients and the implications of our patient analysis.

Is external jugular venous pressure a good predictor of volume status in kidney graft recipients?

To ensure appropriate function of the transplanted organ, it is necessary to adequately maintain vascular volume during the kidney transplantation procedure. For this purpose, central venous pressure (CVP) is monitored through a catheter inserted into the superior vena cava (SVC). Central venous cannulation is associated with a risk of serious complications. An objective of this study was to investigate whether there was a correlation between pressures measured in the SVC and in the external jugular vein (EJV). We studied 33 chronically dialyzed patients who had a short catheter placed in the EJV because of difficulties in peripheral vein cannulation in the limbs. In each case, general anesthesia was induced and a central catheter inserted into the SVC. Every 10 minutes venous pressure measurements were obtained simultaneously at both sites. A significant (P < .001) correlation was observed between external jugular vein pressure (EJVP) and CVP. CVP could be described as a function of EJVP by the equation CVP = {0.90299 x EJVP} - 0.8361. The results of this study indicated that monitoring the EJVP allows equally efficient evaluation of vascular volume as the CVP. In our opinion, EJVP is sufficient to evaluate vascular volume during kidney transplantation in patients with difficult vascular access.

Kidney transplantation and donation in children

It has been shown that kidney transplantation results in superior life expectancy and quality of life compared with dialysis treatment for patients with end-stage renal disease. However, kidney transplantation in children differs in many aspects from adult kidney transplantation. This review focuses on specific issues of surgical care associated with kidney transplantation in children, including timing of transplantation, technical considerations, patient and graft survival, growth retardation and post-transplant malignancy. At the same time, there is a large discrepancy between the number of available donor kidneys and the number of patients on the waiting list for kidney transplantation. There is a general reluctance to use paediatric donor kidneys, because of relatively frequent complications such as graft thrombosis and early graft failure. We review the specific aspects of kidney transplantation from paediatric donors such as the incidence of graft thrombosis, hyperfiltration injury and 'en bloc' transplantation of two kidneys from one donor with an excellent long-term outcome, which is comparable with adult donor kidney transplantation. We also discuss the potential use of paediatric non-heart-beating donor kidneys, from donors whose heart stopped beating with the preservation techniques used.

Global Expression Profiles in 1-Hour Biopsy Specimens of Human Kidney Transplantation from Donors after Cardiac Death

Because of the worldwide shortage of renal grafts, kidney transplantation (KTx) from donors after cardiac death (DCD) is an alternative way to obtain KTx from brain-dead donors. Although the prognosis of DCD KTx is gradually improving, the graft often undergoes delayed graft function (DGF), rendering the control of DGF essential for post-KTx patient care. In an attempt to characterize etiology of DGF, genome-wide gene expression profiling was performed using renal biopsy samples performed at 1 h after KTx from DCD and the data were compared with those of KTx from living donors (LD). A total of 526 genes were differentially expressed between them. Genes involved in acute inflammation were activated, while metabolic pathways were consistently downregulated in DCD. These findings imply the inferior performance of the DCD grafts relative to LD grafts. Several genes were identified where the expression levels were correlated well with parameters indicating short- and long-term prognosis of the DCD patients. In addition, several genes encoding secretory proteins were identified that might reflect the performance of the graft and be potential noninvasive biomarkers. These data provide a good source for candidates of biomarkers that are potentially useful for the control of DGF.

Donor kidney disease and transplant outcome for kidneys donated after cardiac death

Background

Although outcomes of kidney transplants following donation after cardiac death (DCD) and donation after brainstem death (DBD) are similar, generally only optimal younger DCD donors are considered. This study examined the impact of pre-existing donor kidney disease on the outcome of DCD transplants.

Methods

This retrospective study compared the outcome of all DCD kidney transplants performed during 1996–2006 with contemporaneous kidney transplants from DBD donors. Implantation biopsies were scored for glomerular, tubular, parenchymal and vascular disease (global histology score). There were 104 DCD and 104 DBD kidney transplants.

Results

Delayed graft function (DGF) occurred more frequently in DCD than DBD kidneys (64·4 versus 28·8 per cent; P &lt; 0·001). Long-term graft outcome was similar. The only donor factor that influenced outcome was baseline kidney disease, which was similar in both groups, even though DCD donors were younger, with a higher predonation estimated glomerular filtration rate. The global histology score predicted DGF (odds ratio 1·85 per unit; P = 0·006) and graft failure (relative risk 1·55 per unit; P = 0·001), although there was no difference for DCD and DBD kidneys.

Conclusion

Transplant outcomes for DCD and DBD kidneys are comparable. Baseline donor kidney disease influences DGF and graft survival but the impact is no greater for DCD kidneys.

Donor postextubation hypotension and age correlate with outcome after donation after cardiac death transplantation

BACKGROUND

Compared with standard donors, kidneys recovered from donors after cardiac death (DCD) exhibit higher rates of delayed graft function (DGF), and DCD livers demonstrate higher rates of biliary ischemia, graft loss, and worse patient survival. Current practice limits the use of these organs based on time from donor extubation to asystole, but data to support this is incomplete. We hypothesized that donor postextubation parameters, including duration and severity of hemodynamic instability or hypoxia might be a better predictor of subsequent graft function.

METHODS

We performed a retrospective examination of the New England Organ Bank DCD database, concentrating on donor factors including vital signs after withdrawal of support.

RESULTS

Prolonged, severe hypotension in the postextubation period was a better predictor of subsequent organ function that time from extubation to asystole. For DCD kidneys, this manifested as a trend toward increased DGF. For DCD livers, this manifested as increased rates of poor outcomes. Maximizing the predictive value of this test in the liver cohort suggested that greater than 15 min between the time when the donor systolic blood pressure drops below 50 mm Hg and flush correlates with increased rates of diffuse biliary ischemia, graft loss, or death. Donor age also correlated with worse outcome.

CONCLUSIONS

Time between profound instability and cold perfusion is a better predictor of outcome than time from extubation to asystole. If validated, this information could be used to predict DGF after DCD renal transplant and improve outcomes after DCD liver transplant.

[Cell energetic loading in experimental renal transplant with different periods of warm ischemia]

INTRODUCTION AND GOALS

Renal procurement after a period of heart st op demands a previous knowledge of ischemia-reperfusion injuries means. To study cell injury mechanisms an experimental study has been designed in pigs, with different rangres of warm ischemia (0-30-45 and 90 min). The main goal was to research on the basis of ischemic injury.

MATERIAL AND METHODS

Biochemical parameters (creatinine, urine output), energetic loading (ATP, ADP, AMP and global energetic loading) and pathological studies as long as survival analysis by 5th day were completed.

RESULTS

Animal survival and graft viability range from 100% at 5th day in control and 30 min warm ischemia groups to 60% in 90 min warm ischemia group. Creatinine levels rises at 1st, 3rd and 5th day, especially in those non-viable organs. ATP levels decrease after warm ischemia period, increases ADP and AMP levels after reperfusion in those viable organs.

CONCLUSIONS

Prolonged periods of warm ischemia do not result necessarily in non-viable kidneys. Viable organs recover nucleotide levels early. Study of energetic cell loading levels is a good way to get on better in the knowledge of injury mechanisms after ischemia-reperfusion.

Cold ischemia is a major determinant of acute rejection and renal graft survival in the modern era of immunosuppression

BACKGROUND

The aim of our study was to examine, in a recent cohort of kidney transplant recipients who have received modern immunosuppressive therapy, the respective role of cold ischemia time (CIT) and delayed graft function (DGF) on acute rejection (AR) rates and long-term graft survival.

METHODS

We retrospectively reviewed the charts of 611 renal transplantations between 1996 and 2005. Most patients received a calcineurin inhibitor as maintenance therapy, either cyclosporine (43%) or tacrolimus (52%) and 76% of the patients received an antilymphocyte induction therapy. Study endpoints were DGF, first-year AR, and long-term graft survival. Uni- and multivariate analyses were performed to determine factors that may have influenced the study outcomes.

RESULTS

DGF was observed in 16.2% of patients. Both older donor age and longer CIT were significant risk factors for DGF. DGF rates were similar whether patients received a calcineurin inhibitor before transplantation or not. AR occurred in 16.5% of grafts during the first year. Independent predictors of AR by multivariate analysis were duration of dialysis, CIT, current panel-reactive lymphocytotoxic antibody more than 5%, and the number of human leukocyte antigen-A, B, and DR mismatches. Each hour of cold ischemia increases the risk of rejection by 4%. With respect to death-censored graft survival, three pretransplant parameters emerged as independent predictors of graft loss: younger recipient age, peak panel-reactive lymphocytotoxic antibody more than 5% and longer CIT. The detrimental effect of CIT on graft survival was entirely because of its propensity to trigger AR. When AR was added to the multivariate Cox model, CIT was no longer significant whereas first-year AR became the most important predictor of graft loss (Hazards ratio, 4.6).

CONCLUSION

Shortening CIT will help to decrease not only DGF rates but also AR incidence and hence graft loss. Patients with prolonged CIT should receive adequate immunosuppression, possibly with antilymphocyte preparations, to prevent AR occurrence.

The relative effects of warm and cold ischemic injury in an experimental model of nonheartbeating donor kidneys

BACKGROUND

Ischemia reperfusion injury (I/R) leads to delayed graft function and remains an important problem in renal transplantation. The aim of this experimental study was to assess the effects of warm (WI) and cold ischemia (CI) in models of heartbeating (HBD) and controlled/uncontrolled nonheartbeating donor (NHBD) kidneys.

METHODS

A reperfusion model utilizing cardiopulmonary bypass technology was used to perfuse isolated porcine kidneys with autologous blood after the following conditions: 0 min WI+2 h cold storage (CS); 0 min WI+18 h CS; 10 min WI+2 h CS; 10 min WI+18 h CS; 25 min WI+2 h CS; 25 min WI+18 h CS. Renal function was measured over a period of 3 hr.

RESULTS

Renal functional parameters were not significantly different between 0, 10, 25 WI with 2 h CS [AUC creatinine (Cr) decrease of 1057+/-177, 1102+/-260, and 1245+/-143 micromol/L h, P=0.338; AUC creatinine clearance (CrCl) of 37.7+/-15.8, 36.2+/-21.7, 19.8+/-9.1 ml/min/100 g h, P=0.099]. After 18 h CS, renal function was severely impaired in the 10 and 25 WI groups compared to 0 min WI [AUC Cr of 2156+/-401, 2287+/-148, 1563+/-395 micromol/L h, P=0.037; AUC CrCl of 2.2+/-1.7, 1.5+/-1.5, 21.7+/-13.4 ml/min/100 g h, P=0.007).

CONCLUSION

Warm ischemia of up to 25 min was only detrimental to renal function when kidneys were subsequently preserved in cold storage for 18 hr. This data suggests that limiting the cold storage period is of paramount importance when transplanting kidneys subjected from nonheartbeating donors.