Renal allograft loss in the first post-operative month: causes and consequences

Intra-operative duplex ultrasound scanning in renal transplantation: protocol and service requirements

Intra-operative duplex ultrasound in renal transplantation was first described in 1998 and whilst reported in problematic cases, there are few reports of its routine use and no current published protocols. Since 2013, we have used intra-operative ultrasound in all renal transplants. The formal protocol used since August 2020 is presented as a reference document for other transplant centres. A Canon Aplio 800 ultrasound system with an i22LH8 hockey-stick transducer is used to image the renal cortex and major vessels, and an i8CX1 matrix transducer to image the graft during and after fascial closure. These transducers are fully sterilised with Sterrad and no sheathing of transducers is required. The transplant surgeon scans within the sterile field with the sonographer guiding imaging and adjusting machine settings. Ultrasound findings are discussed between team members including any requirement for interventions. Ultrasound is performed at three stages of the operation: Stage 1: after clamp release identifying issues of graft vascularity including otherwise unrecognised major vessel and anastomotic abnormalities. Stage 2: following ureteric implantation identifying compromised perfusion due to graft rotation or vessel kinking. Stage 3: after fascial closure identifying compromised perfusion due to external compression. Post-operative scanning, including assessment of the collecting system and bladder, is performed routinely on days 1, 3, 7 and 30. The intervention is effective with no early graft losses or peri-operative vascular thromboses. The requirements for service provision are significant including the availability of additional transducers, and sonographers with expertise in intra-operative scanning able to attend after-hours for extended periods.

Predictive Value of Camera-based Donor Glomerular Filtration Rate Estimation on the Immediate Renal Allograft Outcome Following Live-related Renal Transplant: A Single-center Retrospective Study

Purpose of the Study

The purpose of this study was to assess the association of measured glomerular filtration rate (mGFR) using camera-based method with early transplant outcomes.

Methodology

Diethylenetriamine pentaacetate renograms of all voluntary kidney donors between January 2016 and December 2022 at Kasturba Hospital, Manipal, India, were retrieved for the study. Recipients' posttransplant biochemical parameters were collected and compared against donors with scaled mGFR >80 ml/min/1.73 m2 (Group 1) and with mGFR between 60 and 80 ml/min/1.73 m2 (Group 2). Donor-recipient pair age, anthropometric parameters, and their differences were also assessed against the immediate transplant outcome. Posttransplant immediate graft function was assessed by posttransplant nadir serum creatinine, day to achieve nadir serum creatinine, the incidence of slow graft or delayed graft function, and serum creatinine at 1-month posttransplantation. Recipients with serum creatinine of >2.5 mg/dl on posttransplant day 7 were taken as slow graft function.

Results

A total of 161 donor-recipient pairs were analyzed in the study. In recipients who showed persistently high serum creatinine posttransplant, older donor age(p < 0.001), higher difference in body mass index among the donor-recipient pair (p= 0.03), and mGFR <80ml/min (p < 0.001) were significantly associated. Slow graft function was significantly more in Group II recipients, with donors having mGFR <80ml/min as compared to Group I with mGFR >80 ml/min (37.3% vs. 10.6%) (P < 0.001).

Conclusions

Camera-based mGFR using Gates' formula is a reliable tool to predict inferior graft outcomes in the immediate posttransplant period. Kidneys from donors with mGFR of 60-80 mL/min/1.73 m2 are likely to experience slow graft function in the immediate posttransplant period.

Early Outcomes in Renal Transplantation With Routine Intraoperative Duplex Ultrasound

BACKGROUND

While intra-operative duplex ultrasound scanning can be readily performed in renal transplantation, the value of this intervention in routine practice is not established.

METHODS

Three hundred thirty-one consecutive single renal transplants in adult recipients underwent intraoperative scanning at implantation. Early graft losses were compared with those recorded in the ANZDATA Registry.

RESULTS

Nine overt vascular abnormalities were corrected prior to scanning. Four further suspected venous outflow restrictions were confirmed by ultrasound and revised. Another 11 major vascular revisions were performed following intraoperative ultrasound consisting of 7 otherwise unsuspected inflow abnormalities, all corrected, and 4 anastomoses redone to reposition the graft. Thirty-two (9.7%) grafts were repositioned under ultrasound guidance to improve cortical perfusion but without vascular revision. One graft with hyperacute rejection was explanted 4 days postimplantation and one graft with primary nonfunction remained well perfused. Two patients died within 90 days, both with functioning grafts. Twenty-three grafts were re-explored within 7 days, including 9 solely for graft hypoperfusion. There were no postoperative arterial thromboses and, at re-exploration, no arterial anastomoses required revision. There were no postoperative venous thromboses, although one venous anastomosis was revised. No grafts were lost within 90 days for surgical or technical reasons compared with 76 (1.0%) of 7603 contemporaneous grafts in the ANZDATA Registry (P = .077 Fisher's exact test, P = .069 χ² test).

CONCLUSIONS

The routine use of intraoperative ultrasound appears to be of benefit by identifying otherwise unrecognized vascular abnormalities, leading to a reduction in early graft losses because of surgical factors.

RETRACTED:Predictive Factors of Surgical Complications in the First Year Following Kidney Transplantation

This article has been retracted: please see Elsevier Policy on Article Withdrawal ( https://www.elsevier.com/locate/withdrawalpolicy ). The article has been retracted at the request of the last author, Sebastien Deglise, due to significant violations of research standards during the course of the study which do not ensure the reliability of the published data and of which the author has informed the journal that he was unaware at the time of the publication.

Association Between Side of Living Kidney Donation and Post-Transplant Outcomes

Background: Right-sided living donor kidneys have longer renal arteries and shorter veins that make vascular anastomosis more challenging. We sought to determine whether recipients of right-sided living donor kidneys have worse outcomes than left-sided kidney recipients.

Methods: An observational analysis of the Australia and New Zealand Dialysis and Transplant Registry (ANZDATA) was undertaken. We used adjusted logistic regression to determine the association between side and delayed graft function (DGF) and time-stratified adjusted cox regression models for graft and patient survivals.

Results: Between 2004 and 2018, 4,050 living donor kidney transplants were conducted with 696 (17.2%) using right kidneys. With reference to left kidneys, the adjusted OR (95% CI) for DGF was 2.01 (1.31–3.09) for recipients with right kidneys. Within 30 days, 46 allografts (1.4%) were lost, with major causes of overall graft loss being technical, primary non-function and death. Recipients of right donor kidneys experienced a greater risk of early graft loss (aHR 2.02 [95% CI 1.06–3.86], p = 0.03), but not beyond 30 days (aHR 0.97 [95% CI 0.80–1.19], p = 0.8]).

Conclusion: Technical challenge is the most common cause of early graft loss. The risk of early graft loss among recipients who received right kidneys is doubled compared to those who received left living donor kidneys.

The Impact of Inflammation on the Immune Responses to Transplantation: Tolerance or Rejection?

Transplantation (Tx) remains the optimal therapy for end-stage disease (ESD) of various solid organs. Although alloimmune events remain the leading cause of long-term allograft loss, many patients develop innate and adaptive immune responses leading to graft tolerance. The focus of this review is to provide an overview of selected aspects of the effects of inflammation on this delicate balance following solid organ transplantation. Initially, we discuss the inflammatory mediators detectable in an ESD patient. Then, the specific inflammatory mediators found post-Tx are elucidated. We examine the reciprocal relationship between donor-derived passenger leukocytes (PLs) and those of the recipient, with additional emphasis on extracellular vesicles, specifically exosomes, and we examine their role in determining the balance between tolerance and rejection. The concept of recipient antigen-presenting cell "cross-dressing" by donor exosomes is detailed. Immunological consequences of the changes undergone by cell surface antigens, including HLA molecules in donor and host immune cells activated by proinflammatory cytokines, are examined. Inflammation-mediated donor endothelial cell (EC) activation is discussed along with the effect of donor-recipient EC chimerism. Finally, as an example of a specific inflammatory mediator, a detailed analysis is provided on the dynamic role of Interleukin-6 (IL-6) and its receptor post-Tx, especially given the potential for therapeutic interdiction of this axis with monoclonal antibodies. We aim to provide a holistic as well as a reductionist perspective of the inflammation-impacted immune events that precede and follow Tx. The objective is to differentiate tolerogenic inflammation from that enhancing rejection, for potential therapeutic modifications. (Words 247).

Pre-transplant donor-specific HLA antibodies and risk for poor first-year renal transplant outcomes: results from the Swiss Transplant Cohort Study

The aim of this study was to analyze first year renal outcomes in a nationwide prospective multicenter cohort comprising 2215 renal transplants, with a special emphasis on the presence of pre-transplant donor-specific HLA antibodies (DSA). All transplants had a complete virtual crossmatch and DSA were detected in 19% (411/2215). The investigated composite endpoint was a poor first-year outcome defined as (i) allograft failure or (ii) death or (iii) poor allograft function (eGFR ≤25 ml/min/1.73 m² ) at one year. Two hundred and twenty-one (221/2215; 10%) transplants showed a poor first-year outcome. Rejection (24/70; 34%) was the most common reason for graft failure. First-year patient's death was rare (48/2215; 2%). There were no statistically significant differences between DSA-positive and DSA-negative transplants regarding composite and each individual endpoint, as well as reasons for graft failure and death. DSA-positive transplants experienced more frequently rejection episodes, mainly antibody-mediated rejection (both P < 0.0001). The combination of DSA and any first year rejection was associated with the overall poorest death-censored allograft survival (P < 0.0001). In conclusion, presence of pre-transplant DSA per se does not affect first year outcomes. However, DSA-positive transplants experiencing first year rejection are a high-risk population for poor allograft survival and may benefit from intense clinical surveillance.

Kidney Transplants in Controlled Donation Following Circulatory Death, or Maastricht Type III Donors, With Abdominal Normothermic Regional Perfusion, Optimizing Functional Outcomes

Supplemental Digital Content is available in the text.

Background.

Warm ischemia time and ischemia-reperfusion damage result in higher rates of delayed graft function and primary nonfunction in kidney transplants (KTs) from controlled donation after circulatory death (cDCD). This study aimed to assess early and late kidney function and patient and graft survival of KT from cDCD preserved with normothermic regional perfusion (NRP) and to compare with KT from brain death donors (DBDs) and cDCD preserved with rapid recovery (RR).

Methods.

Patients who received a KT at our institution from 2012 to 2018 were included, with a minimum follow-up period of 1 y. They were categorized by donor type and conditioning methods: DBD, cDCD with NRP, and cDCD with RR. Early and late graft function, along with patient and graft survival were analyzed in all groups.

Results.

A total of 182 KT recipients were included in the study (98 DBD and 84 cDCD). Out of the cDCDs, 24 kidneys were recovered with the use of NRP and 62 with RR; 22 of the 24 kidneys were ultimately transplanted. The cDCD using NRP group showed lower rates of delayed graft function compared with the cDCD with RR group (36.3% versus 46.7%, P = 0.01). Also, primary nonfunction rates were lower in the cDCD using NRP group (4.5% versus 6.4% cDCD-RR and 10.2% DBD). Patient survival rates were >90% in all groups. No differences were found in graft survival rates at 1 y.

Conclusions.

The use of abdominal NRP improves early function recovery of KT from cDCD, making their outcomes comparable with those of DBD.

Rapid re-transplantation safety following early kidney graft loss

INTRODUCTION

Early graft loss is a devastating kidney transplant complication associated with high mortality and an increased risk of sensitization to antigens from the failed graft. Moreover, if rapid re-transplantation were to occur, given that the human leukocyte antigen antibodies identification may not be reliable until several weeks after transplantation, the recipient's immunological status would be uncertain. Hence, there could be an increased immunological risk. To date, there is no information on whether a rapid re-transplantation after early graft loss, without a new reliable anti-HLA determination, is safe.

METHODS

We retrospectively analysed the number of rejections and the graft survival of re-transplanted patients with early graft loss (defined as graft failure before 30 days from transplant) from our centre between June 2003 and November 2019. The studied population was divided into rapid re-transplantation (performed within 30 days of early graft loss) and late re-transplantation (performed beyond those 30 days).

RESULTS

Forty-seven patients were re-transplanted after early graft loss. There were nine rapid re-transplantation cases with an 89% five-year graft survival and one antibody-mediated rejection episode. Furthermore, we identified 38 cases of late re-transplantation with a 69% five-year graft survival, 4 T cell-mediated, and 11 antibody-mediated rejections.

CONCLUSIONS

Rapid re-transplantation appears to be safe and does not entail increased rejection risk, nor does it impact long-term graft survival when compared to late re-transplantation.

KDIGO Clinical Practice Guideline on the Evaluation and Management of Candidates for Kidney Transplantation

The 2020 Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline on the Evaluation and Management of Candidates for Kidney Transplantation is intended to assist health care professionals worldwide who evaluate and manage potential candidates for deceased or living donor kidney transplantation. This guideline addresses general candidacy issues such as access to transplantation, patient demographic and health status factors, and immunological and psychosocial assessment. The roles of various risk factors and comorbid conditions governing an individual's suitability for transplantation such as adherence, tobacco use, diabetes, obesity, perioperative issues, causes of kidney failure, infections, malignancy, pulmonary disease, cardiac and peripheral arterial disease, neurologic disease, gastrointestinal and liver disease, hematologic disease, and bone and mineral disorder are also addressed. This guideline provides recommendations for evaluation of individual aspects of a candidate's profile such that each risk factor and comorbidity are considered separately. The goal is to assist the clinical team to assimilate all data relevant to an individual, consider this within their local health context, and make an overall judgment on candidacy for transplantation. The guideline development process followed the Grades of Recommendation Assessment, Development, and Evaluation (GRADE) approach. Guideline recommendations are primarily based on systematic reviews of relevant studies and our assessment of the quality of that evidence, and the strengths of recommendations are provided. Limitations of the evidence are discussed with differences from previous guidelines noted and suggestions for future research are also provided.

Early Graft Loss after Deceased-Donor Kidney Transplantation: What Are the Consequences?

BACKGROUND

Decreasing kidney discards continues to be of paramount importance for improving organ transplant access, but transplantation of nonideal deceased donor kidneys may have higher inherent risks of early graft loss (EGL). Patients with EGL (defined as graft failure within 90 days after transplant) are allowed reinstatement of waiting time according to United Network for Organ Sharing (UNOS) policy. The purpose of this study was to examine outcomes for patients experiencing EGL.

STUDY DESIGN

We performed a single center retrospective review of adult deceased donor kidney transplant (DDKT)-alone recipients from 2001 to 2018, comparing those with EGL (including primary nonfunction [PNF]) to those without.

RESULTS

EGL occurred in 103 (5.5%) of 1,868 patients, including 57 (55%) PNF, 25 (24%) deaths, 16 (16%) thrombosis, 3 (3%) rejection, and 2 (2%) disease recurrence. Kidney Donor Profile Index (KDPI) > 85% and donation after circulatory death (DCD) DDKTs did not increase risk of either EGL or PNF unless combined with prolonged cold ischemic time (CIT). For KDPI >85% with CIT >24 hours, the risk of EGL or PNF was tripled (EGL odds ratio [OR] 2.9, 95% CI 1.6-5.2; PNF OR3.6, 95% CI1.7-7.7). For DCD with CIT > 24 hours, increased risks were likewise seen for EGL (OR 2.4, 95% CI 1.3-4.3), and PNF (OR 3.2, 95% CI 1.5-7). One-year and 5-year patient survival rates were 60% and 50% after EGL, 80% and 73% after PNF, and 99% and 87% for controls, respectively. Only 24% of either EGL or PNF patients underwent retransplantation.

CONCLUSIONS

EGL and PNF were associated with low retransplantation rates and inferior patient survival. Prolonged CIT compounds risks associated with KDPI > 85% and DCD donor kidneys. Therefore, policies promoting rapid allocation and increased local use of these kidneys should be considered.

Surgical complications risk in obese and overweight recipients for kidney transplantation: a predictive morphometric model based on sarcopenia and vessel-to-skin distance

PURPOSE

Sarcopenia or adipose tissue distribution within obese and overweight renal transplanted have been poorly evaluated. Our objective was to evaluate morphometric markers to predict surgical complications in kidney transplantation.

METHODS

We retrospectively included patients with a BMI > 25 kg/m² undergoing kidney transplantation from 2012 to 2017. Following measurements were performed on CT-scan sections: Sub-cutaneous Adipose Tissue surface (SAT), Visceral Adipose Tissue surface (VAT), Vessel-to-Skin distance (VSK), Abdominal Perimeter (AP), and Psoas surface. A multivariable logistic regression model with BMI was compared to a model containing morphometric variables to determine the best predictive model for surgical complications.

RESULTS

248 patients were included, 15 (6%) experienced transplant nephrectomy, 18 (7.3%) urinary leakage, and 29 (11.7%) subcapsular renal hematoma. Multivariable logistic regression evidenced that sarcopenia and VSK were risk factors of surgical complication within a year post-transplantation (respectively, OR = 0.9, 95%CI (0.8-0.9), p = 0.04 and OR = 1.2, 95%CI (1.1-1.3), p = 0.002). Area under the curve for a predictive model including VSK, age and psoas surface was 0.69, whereas BMI model was 0.65.

CONCLUSION

Combined morphometric parameters of obesity were associated with surgical complications in kidney transplantation. Morphometric threshold may provide a more accurate and objective criteria than BMI to evaluate kidney transplantation outcomes. External validation is needed.

Analysis of the Effects of Day-Time vs. Night-Time Surgery on Renal Transplant Patient Outcomes

Sleep deprivation and disruption of the circadian rhythms could impair individual surgical performance and decision making. For this purpose, this study identified potential confounding factors on surgical renal transplant patient outcomes during day and night. Our retrospective cohort study of 215 adult renal cadaver transplant recipients, of which 132 recipients were allocated in the “day-time” group and 83 recipients in the “night-time” group, primarily stratified the patients into two cohorts, depending on the start time. Within a 24 h operational system, “day-time” was considered as being from 8 a.m. to 8 p.m. and “night-time” from 8 p.m. to 8 a.m.. Primary outcomes examined patient and graft survival after three months and one year. Secondary outcomes included the presence of acute rejection (AR) and delayed graft function (DGF), as well as the rate of postoperative complications. In log-rank testing, “day-time” surgery was associated with a significantly higher risk of patient death (p = 0.003), whereas long-term graft survival was unaffected by the operative time of day. The mean cold ischemia time (CIT), which was 12.4 ± 5.3 h in the “night-time” group, was significantly longer compared to 10.7 ± 3.6 for those during the day (p = 0.01). We observed that “night-time” kidney recipients experienced more wound complications. From our single-centre data, we conclude that night-time kidney transplantation does not increase the risk of adverse events or predispose the patient to a worse outcome. Nevertheless, further research is required to explore the effect of fatigue on nocturnal surgical performance.

Pharmacokinetics of Enoxaparin After Renal Transplantation in Pediatric Patients

Enoxaparin is commonly used in the prevention of renal allograft vascular thrombosis but off-label in children, and no consensus exists regarding the optimal dosing and dose adjustment. In this retrospective study, 444 anti-Xa levels were obtained from 30 pediatric renal transplant recipients in order to investigate enoxaparin population pharmacokinetics. The main results were (1) 25% of children achieved the target anti-Xa activity 36 hours after initiation of treatment, (2) anti-Xa time courses were best described by a 1-compartment open model with first-order absorption, (3) body weight but not renal function was the sole covariate influencing clearance and volume of distribution, and (4) large between-subject and between-occasion variabilities in anti-Xa activity were observed. However, creatinine-based estimated glomerular filtration rate in the first post-renal transplantation hours may not reliably reflect the actual renal function of the children. Based on the final population model, a Bayesian-based program was developed in order to estimate the individual pharmacokinetic parameters on a single anti-Xa measurement, allowing determination of the next enoxaparin dose that will quickly achieve an appropriate anti-Xa activity (targeting 0.3-0.5 IU/mL) and anticoagulation. Finally, these results should help standardize practices that remain to date largely heterogeneous in pediatric intensive care units.

Outcomes of Kidney Transplantation by Using the Technique of Renal Artery Anastomosis First

Introduction

The surgical technique for kidney transplantation has been well established: the renal vein is anastomosed first, followed by renal artery anastomosis. Alternatively, the renal artery can be anastomosed first and then the renal vein for kidney transplantation. However, there is a lack of data on the outcomes of kidney transplantation by using this alternative approach. The objective of this paper was to review the outcomes of kidney transplant by using this approach.

Methods

A review of 205 consecutive kidney transplants was conducted. All kidney transplants were performed by doing renal artery anastomosis first and then the renal vein. Data were collected, including vascular/urological complications and kidney graft function.

Results

All transplants were performed successfully with no occurrence of renal artery/vein thrombosis and urine leakage. There were five cases of renal artery stenosis that were managed with endovascular intervention. There was no recurrence on follow-up. One ureteric stenosis required surgical reconstruction.

Conclusions

This alternative vascular anastomotic technique is efficient and safe. It avoids flip-flopping the kidney graft during the vessel anastomoses and may be more practical in minimally invasive surgery for a kidney transplant due to the space constraint.

Early failure of kidney transplants in the current era-a national cohort study

Although short-term outcome after kidney transplantation has improved, a small proportion of grafts are lost during the first year. We characterize in detail all early graft losses in the current era in a nationwide cohort of kidney transplant recipients. Altogether 2447 kidney transplantations, performed between June 2004 and October 2016, were included. All graft losses (return to dialysis or patient death) occurring during the first post-transplant year were characterized. During the first post-tranplant year, altogether 109 grafts were lost, 67 grafts failed, and 42 patients died. Fifty-five per cent of the deaths were due to cardiovascular causes, and 29% due to infectious causes. Twenty-one per cent of the failed grafts were primary nonfunction of unknown reason, 34% were lost due to venous thrombosis and 9% due to arterial thrombosis, but only 10 (15%) patients lost a graft due to acute cellular or humoral rejection. Independent risk factors for death included diabetes, and longer duration of pretransplant dialysis treatment, whereas risk factors for graft failure included increased level of panel-reactive antibodies and increased cold ischaemia time. Kidney allografts are rarely lost due to immunological reasons during the first post-transplant year. The most common causes of early death after transplantation are cardiovascular and infectious causes.

Early Vascular Thrombosis After Kidney Transplantation: Can We Predict Patients at Risk?

BACKGROUND

Renal transplant is the therapy of choice for patients with chronic renal disease. In recent years, improvement in immunosuppressive drugs reduced early graft loss associated with acute rejection. However, vascular thrombosis, accounting for 5% of early graft loss, can sensitize the recipient for human leukocyte antibodies, reducing the chance for a second transplant. The aim of this study was to identify risk factors for vascular thrombosis in a single transplant center, to design specific prevention protocol.

METHODS

This was a retrospective, case-control study. From the Renal Transplant Unit database, we identified 21 cases of vascular thrombosis in recipients of kidneys from deceased donors. Recipients from the contralateral kidney from the same donor, without vascular complications, were assigned to the control group. Data analyzed included donor, recipient, transplant surgery, and post-operative follow-up. The local ethics committee approved the protocol.

RESULTS

Thrombosis and control groups were comparable for recipient characteristics, cold ischemia time, organ side (right or left), and site of arterial anastomosis. We observed an increased risk for vascular thrombosis in kidneys with multiple veins (odds ratio, 11.32; P = .03). Organ retrieval surgery complications, such as vascular lesions or heterogeneous perfusion, despite normal pre-implantation biopsy, were considered risk factors for vascular thrombosis within the first post-operative day (odds ratio, 7.1; P = .03).

CONCLUSIONS

In this series, multiple renal vein and organ retrieval surgery complications were risk factors for early vascular thrombosis.

Is the Reluctance for the Implantation of Right Donor Kidneys Justified?

Background

The lengths of right renal veins are shorter when compared to their left counterparts. Since the implantation of kidneys with short renal veins is considered more challenging, many surgeons prefer left kidneys for transplantation. Therefore, our hypothesis is that the implantation of right kidneys from living and deceased donors is associated with more technical graft failures as compared to left kidneys.

Methods

Two consecutive cohorts of adult renal allograft recipients of living (n = 4.372) and deceased (n = 5.346) donor kidneys between January 1, 2000 and January 1, 2013 were analyzed. Data were obtained from the prospectively maintained electronic database of the Dutch Organ Transplant Registry. Technical graft failure was defined as failure of the renal allograft within 10 days after renal transplantation without signs of acute rejection.

Results

In the living donor kidney transplantation cohort, the implantation of right donor kidneys was associated with a higher incidence of technical graft failure (multivariate analysis p = 0.03). For recipients of deceased donor kidneys, the implantation of right kidneys was not significantly associated with technique-related graft failure (multivariate analysis p = 0.16).

Conclusions

Our data show that the implantation of right kidneys from living donors is associated with a higher incidence of technique-related graft failure as compared to left kidneys.

Hypercoagulability in Kidney Transplant Recipients

Thrombosis remains an important complication after kidney transplantation. Outcomes for graft and deep vein thrombosis are not favorable. The majority of early kidney transplant failure in adults is due to allograft thrombosis. Risk stratification, early diagnosis, and appropriate intervention are critical to the management of thrombotic complications of transplant. In patients with end-stage renal disease, the prevalence of acquired risk factors for thrombosis is significantly high. Because of hereditary and acquired risk factors, renal transplant recipients manifest features of a chronic prothrombotic state. Identification of hereditary thrombotic risk factors before transplantation may be a useful tool for selecting appropriate candidates for thrombosis prophylaxis immediately after transplantation. Short-term anticoagulation may be appropriate for all patients after kidney transplantation.

Early graft loss after kidney transplantation: risk factors and consequences

Early graft loss (EGL) after kidney transplantation is a catastrophic outcome that is assumed to be more likely after the use of kidneys from suboptimal donors. We therefore examined its incidence, risk factors and consequences in our center in relation to different donor types. Of 801 recipients who received a kidney-only transplant from deceased donors, 50 (6.2%) suffered EGL within 30 days of transplantation. Significant risks factors for EGL were donation after circulatory death (DCD) (odds ratio [OR] 2.88; p = 0.006), expanded criteria donor (ECD) transplantation (OR 4.22; p = 0.010), donor age (OR 1.03; p = 0.044) and recipient past history of thrombosis (OR 4.91; p = 0.001). Recipients with EGL had 12.28 times increased risk of death within the first year, but long-term survival was worse for patients remaining on the waiting list. In comparison with patients on the waiting list but not transplanted, and with all patients on the waiting list, the risk of death after EGL decreased to baseline 4 and 23 months after transplantation, respectively. Our findings suggest that DCD and ECD transplantation are significant risk factors for EGL, which is a major risk factor for recipient death. However, long-term mortality is even greater for those remaining on the waiting list.

Vascular repair utilising immobilised heparin conjugate for protection against early activation of inflammation and coagulation

Ischaemia-reperfusion injury (IRI) poses a major challenge in many thrombotic conditions and in whole organ transplantation. Activation of the endothelial cells and shedding of the protective vascular glycocalyx during IRI increase the risk of innate immune activation, cell infiltration and severe thrombus formation, promoting damage to the tissue. Here, we present a novel one-step strategy to protect the vasculature by immobilisation of a unique multi-arm heparin conjugate to the endothelium. Applying a new in vitro blood endothelial cell chamber model, the heparin conjugate was found to bind not only to primary human endothelial cells but also directly to the collagen to which the cells adhered. Incubation of hypoxic endothelial cells with freshly drawn human blood in the blood chambers elicited coagulation activation reflected by thrombin anti-thrombin formation and binding of platelets and neutrophils. Immobilisation of the heparin conjugate to the hypoxic endothelial cells created a protective coating, leading to a significant reduction of the recruitment of blood cells and coagulation activation compared to untreated hypoxic endothelial cells. This novel approach of immobilising multi-arm heparin conjugates on the endothelial cells and collagen of the basement membrane ensures to protect the endothelium against IRI in thrombotic disorders and in transplantation.

Association of early kidney allograft failure with preformed IgA antibodies to β2-glycoprotein I

In the current immunosuppressive therapy era, vessel thrombosis is the most common cause of early graft loss after renal transplantation. The prevalence of IgA anti-β2-glycoprotein I antibodies (IgA-aB2GPI-ab) in patients on dialysis is elevated (>30%), and these antibodies correlate with mortality and cardiovascular morbidity. To evaluate the effect of IgA-aB2GPI-ab in patients with transplants, we followed all patients transplanted from 2000 to 2002 in the Hospital 12 de Octubre prospectively for 10 years. Presence of IgA-aB2GPI-ab in pretransplant serum was examined retrospectively. Of 269 patients, 89 patients were positive for IgA-aB2GPI-ab (33%; group 1), and the remaining patients were negative (67%; group 2). Graft loss at 6 months post-transplant was significantly higher in group 1 (10 of 89 versus 3 of 180 patients in group 2; P=0.002). The most frequent cause of graft loss was thrombosis of the vessels, which was observed only in group 1 (8 of 10 versus 0 of 3 patients in group 2; P=0.04). Multivariate analysis showed that the presence of IgA-aB2GPI-ab was an independent risk factor for early graft loss (P=0.04) and delayed graft function (P=0.04). There were no significant differences regarding patient survival between the two groups. Graft survival was similar in both groups after 6 months. In conclusion, patients with pretransplant IgA-aB2GPI-ab have a high risk of early graft loss caused by thrombosis and a high risk of delayed graft function. Therefore, pretransplant IgA-aB2GPI-ab may have a detrimental effect on early clinical outcomes after renal transplantation.

Evaluation of the humoral immune response to human leukocyte antigens in Brazilian renal transplant candidates

Pre-transplant sensitization to human leukocyte antigens (HLA) is a risk factor for graft failure. Studies of the immunological profile related to anti-HLA antibodies in Brazilian renal transplant candidates are few. In this study, we evaluated the humoral immune response to HLA antigens in 269 renal transplant candidates, in Paraná State, Brazil. The HLA typing was performed by the polymerase chain reaction sequence-specific oligonucleotide method (PCR-SSO) combined with Luminex technology, using an SSO-LABType commercial kit (One Lambda, Inc., Canoga Park, CA, USA). The percentages of panel-reactive antibodies (PRA) and the specificity of anti-HLA antibodies were determined using the LS1PRA and LS2PRA commercial kits (One Lambda, Inc.). The PRA-positive group consisted of 182 (67.7%) patients, and the PRA-negative group of 87 (32.3%) patients. The two groups differed significantly only with respect to gender. Females were the most sensitized. Among the 182 patients with PRA- positive, 62 (34.1%) were positive for class I and negative for class II, 39 (21.4%) were negative for class I and positive for class II, and 81 (44.5%) were positive for both classes I and II. The HLA-A*02, A*24, A*01, B*44, B*35, B*15, DRB1*11, DRB1*04 and DRB1*03 allele groups were the most frequent. The specificities of anti-HLA antibodies were more frequent: A34, B57, Cw15, Cw16, DR51, DQ8 and DP14. This study documented the profile of anti-HLA antibodies in patients with chronic renal failure who were on waiting lists for an organ in Paraná, and found high sensitization to HLA antigens in the samples.

HMG CoA reductase inhibitor treatment induces dysglycemia in renal allograft recipients

BACKGROUND

Dysglycemia and dyslipidemia are important metabolic complications of organ transplantation. Statins are widely used to control dyslipidemia; however, long-term use of statins is related to diabetes mellitus (DM) and impaired fasting glucose (IFG). The aim of this study was to evaluate the influence of statins on the development of dysglycemia (IFG and/or DM) in renal allograft recipients.

METHODS

A total of 394 patients without previously known DM or IFG who underwent kidney transplantation were enrolled. Patients were grouped into the two groups according to the use of statin (control, n=149; statin, n=245). The major statins used were fluvastatin (80 mg/d, n=134) and atorvastatin (20 mg/d, n=111). We compared the incidence of IFG or DM during the follow-up period.

RESULTS

The incidence of IFG was higher in the statin group than that in the control group (28.6% vs. 8.7%, P<0.001). The incidence of dysglycemia was significantly higher in the statin group (40.0% vs. 15.4%, P=0.001). Time to development of dysglycemia after transplantation was shorter in the statin group than in the control group (38.8±29.7 vs. 47.2±23.3 months, P=0.002). Statin use was associated with an increased risk for dysglycemia after adjustment for age, sex, body mass index, hypertension, cholesterol levels, hepatitis C infection, and type of immunosuppressant (hazard ratio=3.08, 95% confidence interval=1.91-4.98). The dysglycemic effect was more profound in the patients who used atorvastatin than in those who used fluvastatin (hazard ratio=2.21, 95% confidence interval=1.02-4.76).

CONCLUSION

Statin treatment is associated with an elevation in fasting plasma glucose and in the development of dysglycemia in renal allograft recipients.

Renal transplantation dramatically reduces IgA anti-beta-2-glycoprotein I antibodies in patients with endstage renal disease

IgA anti-beta-2-glycoprotein I (aB2GPI) antibodies have been related to vascular pathology in the general population and mainly in hemodialyzed patients (prevalence 33%) in whom an elevated incidence of thrombosis and mortality is found. In this paper we have studied the presence of IgA aB2GPI antibodies at pretransplant and their evolution after transplantation with a cross-sectional-based follow-up study of a cohort of 288 endstage renal disease (ESRD) patients treated with kidney transplantation. Pretransplant IgA aB2GPI levels were elevated 31.7 ± 4.2 U/mL without differences in age or type of dialysis. Patients with different etiologies of ESRD showed higher levels of IgA aB2GPI than blood donors, except the groups of non-IgA glomerular disease and systemic erythematosus lupus, whose nonsignificant differences were observed. IgA aB2GPI antibodies dropped immediately after transplantation (10.7 ± 1.0 U/mL, P < 0.0001), coinciding with a high degree of immunosuppression, and remained significantly lower than that observed in pretransplant status. Prevalence of patients with elevated antibodies was also less in transplanted patients (8.9% versus 30.4%, P < 0.0001). Among, positivity for IgA aB2GPI was higher than in patients who had received their first transplant that those were retransplanted. This finding could have important clinical implications and can suggest new therapeutic strategies in patients with IgA aB2GPI antibodies.

Evidence of enhanced systemic inflammation in stable kidney transplant recipients with low Framingham risk scores

BACKGROUND

While the Framingham risk score (FRS) predicts cardiovascular risk in the general population, it underestimates cardiovascular events in renal transplant recipients (RTR). Inflammation is common in RTR, and it is also a hallmark of vascular injury contributing to cardiovascular events.

OBJECTIVE

To explore the relationship between inflammatory chemokines (CCL family) and FRS in a stable RTR.

METHODS

The modified FRS (2009) was used to calculate the 10-yr probability of CVE in 150 RTR. A cross-sectional study measured plasma levels of 14 CCLs by Luminex technique in 53% (79/150) of the cohort and 28 controls.

RESULTS

43.3% of RTR was classified as low, 16% moderate, and 40.7% high FRS. FRS correlated with eGFR and all CCLs with R of <0.2(p = n.s). Compared with controls, CCL 1,4,8,15, and 27 were equally increased in both the high and low FRS groups (p < 0.04 and 0.03, respectively). The percentage of patients with low FRS and CCL 8,15, and 27 values above the 95% cutoff control levels was 46.1%, 76.9%, and 53.8%, respectively.

CONCLUSIONS

Over one half of stable RTR, including those with low FRS, have increased inflammatory chemokine levels. Inflammation is not accounted for in the FRS, and this may explain the poor performance of FRS in transplant patients.