Risk factors for early hemorrhagic and thrombotic complications after kidney transplantation

Effect of Pre-Transplant Renal Anticoagulation and Antiplatelet Therapy on Post-Transplant Outcomes: A Retrospective Single-Center Study

The management of anticoagulation and antiplatelet therapy in stage V chronic kidney disease (CKD) patients undergoing renal transplantation remains controversial. Some centers advocate for the use of reversal agents or procoagulants preoperatively, while others suggest that transplantation can proceed safely without halting these treatments. This study aims to evaluate the incidence of hemorrhagic and thrombotic complications in the first 72 hours post-transplant in patients receiving anticoagulant or antiplatelet therapy compared to a control group without such treatments. We conducted a retrospective cohort study involving 168 kidney transplant patients at our center from June 2018 to February 2022, with a follow-up period of 6 months post-transplant. Among these, 147 patients were included: 8.2% were anticoagulated, 16.3% were on antiplatelet therapy, and 75.5% received neither treatment. Patients on anticoagulants or antiplatelets were generally older, had a higher prevalence of cardiovascular history, and experienced longer dialysis times. Anticoagulated patients exhibited longer cold ischemia times and increased rates of hyperimmunization, alongside prolonged hospital stays. The overall incidence of hemorrhagic complications in the first 3 days post-transplant was low across all groups: 9% in the control group, 8.3% in anticoagulated patients, and 8.4% in antiplatelet-treated patients, with no significant differences. Blood transfusion rates were 75% for anticoagulated patients, 62.5% for antiplatelet patients, and 51.7% for controls (P = .214). Renal function at 6 months was similar across groups (P = .477), though acute rejection rates were higher in anticoagulated patients (16.6% vs. 4.2% vs. 2.7%; P = .067). No significant differences were found in hemorrhagic and thrombotic complications among the groups.

Evidence-Based Complementary Benefit of the Vascular Surgeon Among the Team of Renal Transplantation; a Single Center Experience

BACKGROUND

In a kidney transplant tertiary referral center; we compared 3 operating team configurations of different surgical specialties to highlight the effect of the operating surgeon's specialty on various operative details and procedural outcome.

METHODS

A total of 50 cases of living donor transplantations were divided into 3 main groups according to the operating surgeons' specialty, the first group (A) includes 12 patients exclusively operated on by urologists with advanced training in transplantation, the second group (B) includes 35 patients operated by combined surgical specialties; a urologist and a vascular surgeon both with advanced transplantation training, and a third group (C) includes 3 cases where the transplant operation commenced with operating urologists as in group (A) but required intraoperative urgent notification of a vascular surgeon to manage unexpected intraoperative technical difficulties or major complications. Cases were studied according to operative details, anastomosis techniques, ischemia times, total procedure time, recovery of urinary output, intensive care unit (ICU) stay, postoperative surgical complications and serum creatinine level for up to 3 years of follow-up.

RESULTS

Study of operative details revealed that total duration of graft ischemia was significantly shorter in group (B) and significantly longer in group (C) (P value 0.001), Total procedural duration also varied significantly between the 3 groups, group (B) being the shortest while group (C) was the longest (P value less than 0.001). Technically; group (A) used only end to end arterial anastomosis as a standard technique, while group (B) used both end-to-end and end-to-side anastomoses as required per each case. End to side anastomosis in group (B) yielded better immediate graft response in the form of change in color, texture, earlier and more profuse postoperative urine volumes (P value 0.025). Furthermore, anastomosis to common and external iliac arteries (group B) yielded earlier and higher urine volumes than the internal iliac artery (P values 0.024 and 0.031 respectively). Group (B) recorded significantly less postoperative perigraft hematomas and lymphoceles compared to the other 2 groups. Equal rates of urine leaks, ICU stay, creatinine levels, patient and grafts survival rates among groups (A) and (B), while postoperative recovery and ICU stay duration were more lengthy in the complicated group (C).

CONCLUSIONS

A vascular surgeon operating in a transplantation team would deal comfortably and efficiently with various vascular related challenges and complications, thus avoiding unnecessary time waste, complications and costs.

Pathophysiological Changes in the Hemostatic System and Antithrombotic Management in Kidney Transplant Recipients

Nowadays, the main cause for early graft loss is renal graft thrombosis because kidney transplant outcomes have improved drastically owing to advances in immunological techniques and immunosuppression. However, data regarding the efficacy of antithrombotic therapy in the prevention of renal graft thrombosis are scarce. Adequate antithrombotic management requires a good understanding of the pathophysiological changes in the hemostatic system in patients with end-stage kidney disease (ESKD). Specifically, ESKD and dialysis disrupt the fine balance between pro- and anticoagulation in the body, and further changes in the hemostatic system occur during kidney transplantation. Consequently, kidney transplant recipients paradoxically are at risk for both thrombosis and bleeding. This overview focuses on the pathophysiological changes in hemostasis in ESKD and kidney transplantation and provides a comprehensive summary of the current evidence for antithrombotic management in (adult) kidney transplant recipients.

Study of Post-Kidney Transplantation Parietal Complications and Presarcopenia

BACKGROUND

Sarcopenia is defined as a loss of muscle mass and strength. Its effects on postoperative outcomes in oncology and geriatrics have already been shown. Approximately 40% of patients in end-stage renal failure are affected with sarcopenia. A recent study suggests that sarcopenia could predict surgical complications after renal transplantation in obese patients. The aim of this study was to evaluate the effect of sarcopenia on parietal complications (eg, wound healing, lymphocele, hematoma).

METHODS

Two indices of muscle fat infiltration (intra-muscular adipose content [IMAC], Hounsfield unit average calculation [HUAC]) and 3 of muscle mass index (total psoas index [TPI], visceral fat area/total abdominal muscle area [VFA/TAMA], and skeletal muscle mass index [SMMI]) were retrospectively measured on pretransplant computed tomography scans for patients undergoing kidney transplantation between 2007 and 2017. Patients were considered sarcopenic when the index was above the third quartile for muscle fat infiltration (IMAC, HUAC) and VFA/TAMA, and under the first quartile for muscle mass (TPI, SMMI). The occurrence of wound healing, collection (hematoma and lymphocele), and acute rejection were compared between sarcopenic and nonsarcopenic patients.

RESULTS

Of 484 transplanted patients, 117 patients had a computed tomography scan before transplantation. Patients with a high HUAC had significantly more collections (P = .02) and total parietal complications (P = .09). Patients with a high IMAC had significantly more acute rejection (P = .001).

CONCLUSIONS

Muscle fat infiltration appears to influence the outcome of renal transplantation. The management of sarcopenia in pretransplantation should be a subject of further research.

Recommendations for living donor kidney transplantation

This Guide for Living Donor Kidney Transplantation (LDKT) has been prepared with the sponsorship of the Spanish Society of Nephrology (SEN), the Spanish Transplant Society (SET), and the Spanish National Transplant Organization (ONT). It updates evidence to offer the best chronic renal failure treatment when a potential living donor is available. The core aim of this Guide is to supply clinicians who evaluate living donors and transplant recipients with the best decision-making tools, to optimise their outcomes. Moreover, the role of living donors in the current KT context should recover the level of importance it had until recently. To this end the new forms of incompatible HLA and/or ABO donation, as well as the paired donation which is possible in several hospitals with experience in LDKT, offer additional ways to treat renal patients with an incompatible donor. Good results in terms of patient and graft survival have expanded the range of circumstances under which living renal donors are accepted. Older donors are now accepted, as are others with factors that affect the decision, such as a borderline clinical history or alterations, which when evaluated may lead to an additional number of transplantations. This Guide does not forget that LDKT may lead to risk for the donor. Pre-donation evaluation has to centre on the problems which may arise over the short or long-term, and these have to be described to the potential donor so that they are able take them into account. Experience over recent years has led to progress in risk analysis, to protect donors' health. This aspect always has to be taken into account by LDKT programmes when evaluating potential donors. Finally, this Guide has been designed to aid decision-making, with recommendations and suggestions when uncertainties arise in pre-donation studies. Its overarching aim is to ensure that informed consent is based on high quality studies and information supplied to donors and recipients, offering the strongest possible guarantees.

Predictive Value of HAS-BLED Score Regarding Bleeding Events and Graft Survival following Renal Transplantation

Objective: Due to the high prevalence and incidence of cardio- and cerebrovascular diseases among dialysis-dependent patients with end-stage renal disease (ERSD) scheduled for kidney transplantation (KT), the use of antiplatelet therapy (APT) and/or anticoagulant drugs in this patient population is common. However, these patients share a high risk of complications, either due to thromboembolic or bleeding events, which makes adequate peri- and post-transplant anticoagulation management challenging. Predictive clinical models, such as the HAS-BLED score developed for predicting major bleeding events in patients under anticoagulation therapy, could be helpful tools for the optimization of antithrombotic management and could reduce peri- and postoperative morbidity and mortality. Methods: Data from 204 patients undergoing kidney transplantation (KT) between 2011 and 2018 at the University Hospital Leipzig were retrospectively analyzed. Patients were stratified and categorized postoperatively into the prophylaxis group (group A)—patients without pretransplant anticoagulation/antiplatelet therapy and receiving postoperative heparin in prophylactic doses—and into the (sub)therapeutic group (group B)—patients with postoperative continued use of pretransplant antithrombotic medication used (sub)therapeutically. The primary outcome was the incidence of postoperative bleeding events, which was evaluated for a possible association with the use of antithrombotic therapy. Secondary analyses were conducted for the associations of other potential risk factors, specifically the HAS-BLED score, with allograft outcome. Univariate and multivariate logistic regression as well as a Cox proportional hazard model were used to identify risk factors for long-term allograft function, outcome and survival. The calibration and prognostic accuracy of the risk models were evaluated using the Hosmer−Lemshow test (HLT) and the area under the receiver operating characteristic curve (AUC) model. Results: In total, 94 of 204 (47%) patients received (sub)therapeutic antithrombotic therapy after transplantation and 108 (53%) patients received prophylactic antithrombotic therapy. A total of 61 (29%) patients showed signs of postoperative bleeding. The incidence (p < 0.01) and timepoint of bleeding (p < 0.01) varied significantly between the different antithrombotic treatment groups. After applying multivariate analyses, pre-existing cardiovascular disease (CVD) (OR 2.89 (95% CI: 1.02−8.21); p = 0.04), procedure-specific complications (blood loss (OR 1.03 (95% CI: 1.0−1.05); p = 0.014), Clavien−Dindo classification > grade II (OR 1.03 (95% CI: 1.0−1.05); p = 0.018)), HAS-BLED score (OR 1.49 (95% CI: 1.08−2.07); p = 0.018), vit K antagonists (VKA) (OR 5.89 (95% CI: 1.10−31.28); p = 0.037), the combination of APT and therapeutic heparin (OR 5.44 (95% CI: 1.33−22.31); p = 0.018) as well as postoperative therapeutic heparin (OR 3.37 (95% CI: 1.37−8.26); p < 0.01) were independently associated with an increased risk for bleeding. The intraoperative use of heparin, prior antiplatelet therapy and APT in combination with prophylactic heparin was not associated with increased bleeding risk. Higher recipient body mass index (BMI) (OR 0.32 per 10 kg/m2 increase in BMI (95% CI: 0.12−0.91); p = 0.023) as well as living donor KT (OR 0.43 (95% CI: 0.18−0.94); p = 0.036) were associated with a decreased risk for bleeding. Regarding bleeding events and graft failure, the HAS-BLED risk model demonstrated good calibration (bleeding and graft failure: HLT: chi-square: 4.572, p = 0.802, versus chi-square: 6.52, p = 0.18, respectively) and moderate predictive performance (bleeding AUC: 0.72 (0.63−0.79); graft failure: AUC: 0.7 (0.6−0.78)). Conclusions: In our current study, we could demonstrate the HAS-BLED risk score as a helpful tool with acceptable predictive accuracy regarding bleeding events and graft failure following KT. The intensified monitoring and precise stratification/assessment of bleeding risk factors may be helpful in identifying patients at higher risks of bleeding, improved individualized anticoagulation decisions and choices of antithrombotic therapy in order to optimize outcome after kidney transplantation.

Risk Factors for Graft Loss Due to Acute Vascular Complications in Adult Renal Transplantation Using Grafts Without Vascular Anomalies

BACKGROUND

Vascular complications are the main cause of early graft loss in renal transplant (RT). A graft with multiple vessels represents the most validated risk factor. The aim of the present study was to identify potential predictive factors for acute vascular complications causing graft loss when graft vascular anomalies are excluded.

METHODS

This is a retrospective case-control (1:3 ratio) study extrapolated from the RT series of the Renal Transplant Unit - Udine University Hospital, during the period 1993-2017. Grafts with multiple vessels and retransplant cases were excluded.

RESULTS

The overall prevalence of graft loss due to acute vascular complications was 2.6% (25/961). Seventeen complicated recipients had grafts without vascular anomalies (case group). The median time between RT and complication was 6 days (interquartile range, 4-23 days). The following types of vascular complications were recorded: 5 isolated renal artery thromboses (0.5%), 4 isolated renal vein thromboses (0.4%), 4 combined renal artery and vein thromboses (0.3%), 3 renal artery ruptures due to mycotic arteritis (0.3%), and 1 renal artery nonmycotic pseudoaneurysm (0.1%). No differences were recorded between the groups in terms of donors and grafts characteristics. Complicated recipients showed a statistically higher prevalence of thromboembolism history (P = .046) and vascular atherosclerosis (P = .048). During the postoperative course, blood stream infections (P = .02), acute rejection (P = .03), bleeding from a nonmacrovascular source (P = .04), and multiple reintervention because of nonvascular complications (P = .03) were identified as significant risk factors.

CONCLUSIONS

Recipient characteristics and post-RT complications rather than donor and graft characteristics are relevant risk factors for graft loss due to acute vascular complications when graft vascular anomalies are excluded.

Perioperative antithrombotic therapy does not increase the incidence of early postoperative thromboembolic complications and bleeding in kidney transplantation - a retrospective study

Perioperative antithrombotic therapy could play a role in preventing thromboembolic complications (TEC) after kidney transplantation (KTx), but little is known on postoperative bleeding risks. This retrospective analysis comprises 2000 single‐organ KTx recipients transplanted between 2011 and 2016 in the two largest transplant centers of the Netherlands. TEC and bleeding events were scored ≤7 days post‐KTx. Primary analyses were for associations of antithrombotic therapy with incidence of TEC and bleeding. Secondary analyses were for associations of other potential risk factors. Mean age was 55 ± 14 years, 59% was male and 60% received a living donor kidney. Twenty‐one patients (1.1%) had a TEC. Multiple donor arteries [OR 2.79 (1.15–6.79)] and obesity [OR 2.85 (1.19–6.82)] were identified as potential risk factors for TEC. Bleeding occurred in 88 patients (4.4%) and incidence varied significantly between different antithrombotic therapies (P = 0.006). Cardiovascular disease [OR 2.01 (1.18–3.42)], pre‐emptive KTx [OR 2.23 (1.28–3.89)], postoperative heparin infusion [OR 1.69 (1.00–2.85)], and vitamin K antagonists [OR 6.60 (2.95–14.77)] were associated with an increased bleeding risk. Intraoperative heparin and antiplatelet therapy were not associated with increased bleeding risk. These regimens appear to be safe for the possible prevention of TEC without increasing the risk for bleeding after KTx.

SerpinC1/Antithrombin III in kidney-related diseases

The gene SerpinC1 encodes a serine protease inhibitor named antithrombin III (ATIII). This protease demonstrates both anticoagulant and anti-inflammatory action. ATIII is the most important coagulation factor inhibitor, and even minor changes in ATIII can significantly alter the risk of thromboembolism. ATIII can also suppress inflammation via a coagulation-dependent or -independent effect. Moreover, apart from ATIII deficiency, ATIII and its gene SerpinC1 may also be related to many diseases (e.g. hypertension, kidney diseases). The present review summarizes how ATIII affects the progress of kidney disease and its mechanism. Further studies are required to investigate how ATIII affects renal function and the treatment.

Hemostatic Parameters according to Renal Function and Time after Transplantation in Brazilian Renal Transplanted Patients

Kidney transplantation is the key for patients with end-stage renal disease, improving quality of life and longer survival. However, kidney transplant triggers an intense inflammatory response and alters the hemostatic system, but the pathophysiological mechanisms of these changes are not completely understood. The aim of this cross-sectional cohort study was to investigate hemostatic biomarkers in Brazilian renal transplanted patients according to renal function and time after transplantation. A total of 159 renal transplanted patients were enrolled and D-Dimer (D-Di), Thrombomodulin (TM), von Willebrand Factor (VWF), and ADAMTS13 plasma levels were assessed by ELISA. An increase of D-Di was observed in patients with higher levels of creatinine. ADAMTS13 levels were associated with creatinine plasma levels and D-Di levels with Glomerular Filtration Rate. These results suggested that D-Di and ADAMTS13 can be promising markers to estimate renal function. ADAMTS13 should be investigated throughout the posttransplant time to clarify the participation of this enzyme in glomerular filtration and acceptance or rejection of the graft in Brazilian transplanted patients.

Assessment of Hemostasis after Plasma Exchange Using Rotational Thrombelastometry (ROTEM)

Background

Therapeutic plasma exchange (TPE)-based protocols immediately before cadaveric donor kidney transplantation have been extensively used in highly sensitized recipients. Plasma is generally preferred over human albumin as replacement fluid to avoid depletion of coagulation factors and perioperative bleeding. The aim of this study was to estimate bleeding risk after TPE replaced with albumin using rotational thromboelastography (ROTEM).

Methodology

Ten patients without overt coagulation abnormalities underwent TPE. Standard laboratory coagulation tests (thromboplastin time, activated partial thromboplastin time (aPTT), international normalized ratio (INR), thrombin clotting time, fibrinogen levels and antithrombin activity) were compared with thrombelastometry analysis (EXTEM and INTEM tests) before and after TPE.

Principal Findings

TPE significantly reduced fibrinogen levels (482 ± 182 vs. 223 ± 122 mg/dL), antithrombin activity (103 ± 11 vs. 54 ± 11 %), and prolonged aPTT (28 ± 3 vs. 45 ± 8 s), thromboplastin time (108 ± 11 vs. 68 ± 11 %), INR (0.95 ± 0.06 vs. 1.25 ± 0.16), and thrombin clotting time (18 ± 2 vs. 20 ± 3 s). INTEM and EXTEM analyses revealed significantly prolonged clot-formation time and reduced maximum clot firmness.

Conclusions/Significance

TPE replaced with albumin induces significant changes in global hemostasis parameters thus potentially increasing bleeding risk. Therefore, pretransplant TPE should be considered carefully in indicated patients before kidney transplantation. The role of the ROTEM point-of-care test to estimate the risk of bleeding in renal transplantation needs to be evaluated in further studies.

Evaluation of bleeding rates in renal transplant patients on therapeutic intravenous heparin

BACKGROUND

It is unknown whether coagulation properties differ between renal transplant and nontransplant patients.

OBJECTIVE

To assess whether renal transplant patients on intravenous (IV) heparin, titrated to therapeutic activated partial thromboplastin times (aPPT; 56-93 seconds), experienced a higher rate of bleeding compared to nontransplant patients.

METHODS

Twenty-nine renal transplant and 29 nontransplant patients receiving IV heparin for a deep vein thrombosis, pulmonary embolism, atrial fibrillation, or acute coronary syndrome were randomly identified through a retrospective chart review.

RESULTS

Renal transplant patients had higher bleeding rates on IV heparin therapy compared to nontransplant patients (31% vs 6.9%, respectively; P = .041). Renal transplant patients experienced a drop in hemoglobin of at least 1 g/dL or the need for a transfusion more often then nontransplant patients (69% vs 45%, respectively; P = .111), although the difference was not statistically significant.

CONCLUSIONS

Further research is necessary to identify the factors contributing to increased rates of bleeding in renal transplant patients on IV heparin and to determine the ideal aPTT to appropriately balance anticoagulation in renal transplant patients.

Successful living-related kidney transplantation in a boy with inherited dysfibrinogenemia

In kidney transplantation, it is essential to avoid acute vascular complications, such as hemorrhage and renal vascular thrombosis, which may often lead to allograft loss. Inherited dysfibrinogenemia is a rare coagulation disorder with a wide spectrum of clinical manifestations, such as excessive bleeding and thrombosis. A 12-yr-old boy, previously diagnosed with renal hypodysplasia, was found to have reduced fibrinogen concentrations. Coagulation tests assessing surgical risk during kidney transplantation showed a discrepancy between functional and immunologic fibrinogen concentrations. Gene analysis confirmed inherited dysfibrinogenemia, with a heterozygous mutation in FGA (Aα Arg16His) in the patient and his mother. Based on the molecular and functional properties of the mutation, and a familial phenotype, in which his aunt had experienced a previous bleeding episode, the patient was considered at greater risk of bleeding than of thrombosis. The patient was administered fibrinogen concentrate before surgery, and kidney transplantation was performed with his father as the organ donor. The patient received additional prophylactic infusions of fibrinogen concentrate postoperatively, and his postoperative course was uneventful. Accurate diagnosis of dysfibrinogenemia, including gene analysis, is important for correctly managing patients with this coagulation disorder who are undergoing kidney transplantation.