Renal allograft thrombosis: can thrombophilia explain the inexplicable?

Positive antiphospholipid antibodies: observation or treatment?

Antiphospholipid antibodies (APLAs) are  primarily directed toward phospholipid-binding proteins and are responsible for thrombotic events. APLAs include anti-β2Glycoprotein I (anti-β2GPI), anticardiolipin (anti-CL) antibodies, and lupus anticoagulant. These antibodies are typical markers of antiphospholipid syndrome (APS) and are a part of its diagnostic criteria. Many data underline the presence of APLAs in other rheumatic diseases (e.g., systemic lupus erythematosus, systemic sclerosis, Sjögren's syndrome, rheumatoid arthritis and Behçet's disease). However, they are also detected in patients with cancer, infection, and neurological disorders. Furthermore, healthy individuals may be carriers of APLAs. Chronic asymptomatic APLAs presence is most common in the elderly and subjects with chronic diseases (including malignancies). Specific kinds of APLAs are considered markers of oncological progression. These antibodies occur in 6% of pregnant women (without diagnosed APS) and are related to many pregnancy complications. Of worth, various types of APLAs are reported to have different prothrombotic properties. The risk of thrombotic events in APLA-positive but clinically naïve patients raises many questions in clinical practice. This manuscript analyses various clinical situations and consequences of the APLAs' presence, particularly in patients without diagnosed APS. The prevalence, etiology, molecular background, and prothrombotic properties of numerous APLAs are broadly discussed. The new management approach in different clinical conditions and organ complications is present in the context of recent recommendations. Discussed data underlines that adequate and timely introduced thromboprophylaxis can decrease the risk of thrombus formation and prevent increased morbidity.

Evanescing renal allograft cortical necrosis from living donor renal transplantation: A lesson learned over two decades

BACKGROUND

Renal graft cortical necrosis (GCN) is a catastrophic cause of graft failure. We evaluated the incidence, causes, management, and outcome of GCN across two decades from our center.

METHODS

This is a retrospective analysis of transplant patients who had biopsy-proven GCN transplanted between 2000 and 2020. The clinical details, immunological workup, induction, maintenance regimen, causes of cortical necrosis, and the outcomes were compared between the first period 2000-2012, and the second period 2013-2020, when Flow cytometric and Luminex based crossmatch were included in the workup plan.

RESULTS

Among 2333 live ABO-compatible renal transplants, 37 (0.015%) patients (36 patients between 2000 and 2012 and 1 between 2013 and 2020) developed GCN (60% had diffuse and 40% patchy GCN) at a median of 8 days after transplantation.Twenty-six (60%) received ATG, 4 received plasmapheresis, and ATG (10.8%) as antirejection therapy. The cyclosporine-based regimen was associated with a higher risk of GCN (RR 2.54; 95% CI 1.26 to 5.12, p = 0.009), whereas tacrolimus-based therapy had a lower risk (RR 0.39; 95% CI 0.19 to 0.79, p = 0.009). The introduction of flow cytometry and DSA assay has significantly decreased the incidence of acute rejection and GCN. Only one patient had GCN during the 2013-2020 period because of graft's mucormycosis. Twenty-five (67.56%) patients had no recovery, and 12 (32.43%) had partial recovery of graft function.

CONCLUSION

GCN is mainly associated with rejection, and cyclosporin-based maintenance regimen had a higher incidence. The remarkable decrease in GCN after 2013 onwards could be attributed to the use of Flowcytometry, Luminex-based DSA assays, and tacrolimus-based regimens.

Kidney allograft infarction associated with transplant renal artery stenosis in a COVID-19 kidney transplant recipient

Kidney allograft infarction is rare, but an urgent condition that requires prompt intervention to avoid allograft loss. Renal artery thrombosis is the leading cause of infarction. Apart from traditional risk factors for thrombosis, emerging SARS-CoV-2 predisposes patients to thrombotic diseases both in arterial and venous vasculatures. We report a case of kidney transplant recipient with known transplant renal artery stenosis (TRAS) status post angioplasty with severe COVID-19, complicated by oliguric acute kidney injury requiring continuous renal replacement therapy (CRRT). She did not have a history of thromboembolic disease. The hospital course was complicated by new-onset atrial and ventricular fibrillation and cardiac arrest requiring multiple rounds of cardiopulmonary resuscitation. She had no signs of renal recovery, and an abdominal CT scan showed evidence of allograft infarcts. She underwent an allograft nephrectomy. Pathology revealed diffuse thrombotic microangiopathy involving glomeruli, arterioles, and arteries associated with diffuse cortical infarction with negative SARS-CoV-2 immunostain and in situ hybridization. This is the first case of kidney allograft infarct with a history of TRAS in a COVID-19 patient. Underlying TRAS and COVID-19-associated thrombosis in this patient are unique and likely play a key role in allograft infarction from arterial thrombosis. Recognizing risk factors and early therapy for allograft infarction may improve transplant outcomes.

End-stage renal disease and thrombophilia

Chronic kidney disease is an established risk factor for arterial and venous thromboembolism (TE). Whereas the overall risk of TE in moderately decreased kidney function is approximately 2.5-fold higher compared to patients with normal renal function, the risk increase is 5.5-fold in patients with severe renal dysfunction. In patients with renal dysfunction and arterial thrombosis (OR: 4.9), malignancy (OR: 5.8) surgery (OR: 14.0) or thrombophilia (OR: 4.3) the risk to suffer from venous TE is higher compared to the risk associated to the baseline renal dysfunction alone. The treatment options for end-stage renal diseases include hemodialysis, peritoneal dialysis and kidney transplantation. During all treatment modalities thrombotic complications have been described, namely catheter malfunction and shunt thrombosis in patients undergoing hemodialysis in up to 25% of patients, and TE, pulmonary embolism or graft vessel thrombosis in approximately 8% of patients. The reported incidence of reno-vascular thrombosis following renal transplantation leading to hemorrhagic infarction with organ rejection or organ loss varied between 2-12%. Keeping in mind the multifactorial etiology of TE in patients with kidney dysfunction a general screening for thrombophilia in this patient group is not indicated. Selected screening on an individual patient basis should be discussed if the family history for TE is positive or the patient itself had suffered one thrombosis before the onset of the renal disease or multiple TEs during hemodialysis or post kidney transplantation in patients waiting for living donor kidney transplantation.

Acute Allograft Renal Vein Thrombosis: A Case Report

Renal graft thrombosis is a serious and devastating complication of renal transplant that ultimately results in graft loss. It is associated with acute and hyper-acute rejections; however, the underlying cause in large proportion of patients remains unknown. We report a case of a young male who underwent live related kidney transplant but lost the graft on the operating table due to renal vein thrombosis (RVT).

Does oral health contribute to post-transplant complications in kidney allograft recipients?

OBJECTIVE

The significant number of complications in kidney graft recipients can not be easily explained. The paper assesses whether poor oral health increases the risk of acute rejections and hospitalizations in kidney allograft recipients.

MATERIALS AND METHODS

Ninety-one kidney transplant recipients were divided into three sub-groups according to post-transplant time (< 1, 1-5 and > 5 years). Dental examination evaluated oral hygiene index (OHI-S) and Community Periodontal Index of Treatment Needs (CPITN), which were correlated with the occurrence of post-transplant complications.

RESULTS

Within the first year after transplantation the indicators of the increased risk of hospitalizations and acute rejection episodes was the OHI-S (hazard ratio 1.02 and 1.11, respectively), also CPITN score correlated with acute rejections (R = 0.82, p < 0.01).

CONCLUSION

The neglect in oral health is associated with the increased risk of clinical complications within first year after kidney transplantation.

[Incidence of thrombophilia and risk of renal vessel thrombosis in kidney transplant recipients]

INTRODUCTION

Kidney transplantation is the optimal treatment of end stage kidney disease. The most common vascular complication in the early postoperative period is thrombosis of the renal artery and vein. These complications usually lead to the loss of the transplanted kidney.

AIM

of our study was to identify those factors which represent an increased risk for thrombotic complication and determine whether routine screening for thrombophilia is justifiable before transplantation. As an illustration to this problem we report a case of successful renal vein recanalisation after thrombosis.

METHODS

We give an overview of the literature about incidence of renal graft thrombosis, hypercoagulable states, predictive value of factor V. Leiden and prothrombin G20210A mutations in venous thromboembolism. We discuss those publications that suggest a preoperative screening of transplant candidates for hypercoagulable states and thrombophilia and those that do not think that such screening is reasonable. In our case a 28 year old male patient received a cadaveric kidney. Thrombosis of the renal vein was diagnosed 8 hours after transplantation. Reoperation was performed immediately: venous anastomosis was opened, the thrombus removed. After reoperation the circulation of the kidney recovered, intravenous heparin treatment was introduced immediately.

RESULTS

24 months later the kidney is still functioning well. Postoperative thrombophilia screening showed heterozygosity for factor V Leiden.

CONCLUSION

There are only few publications reporting on successful recanalisation after renal vein thrombosis. In our case rapid diagnosis and immediate operative treatment saved the graft. There is no uniform proposal in the literature whether preoperative screening for thrombophilia is justifiable or not. In our view screening for thrombophilia and thromboprophylaxis is mandatory. Extensive prospective studies should be undertaken to refine the risks and establish the associations of thrombophilia and thromboembolism after kidney transplantation.

The treatment of deep vein thrombosis immediately after kidney transplantation: a case report

Ipsilateral acute iliofemoral deep vein thrombosis (DVT) immediately after kidney transplantation is rare but highly morbid, resulting in allograft failure, rupture, or even death. Treatment modalities for iliofemoral DVT occurring just after transplantation are limited due to bleeding risk and impaired renal function. A 55-year-old woman with end-stage renal disease from hypertension underwent a living nonrelated donor procedure using a kidney from her husband. On postoperative day 1, the patient presented edema and pain in the right lower extremity associated with local heat and redness. The symptoms became aggravated with time. Duplex ultrasonography (US) revealed a DVT involving from the right femoral vein to the common iliac vein and an increased resistive index of 0.96 to 0.97. A venogram using carbon dioxide as the contrast medium showed also same findings as the duplex US. After inferior vena cava filter insertion, percutaneous transluminal thromboaspiration (PTA) was performed with complete removal of the thrombus. Early PTA with carbon dioxide as intravenous contrast material seemed to be an effective and safe procedure to treat this complication.

Intragraft vascular occlusive sickle crisis with early renal allograft loss in occult sickle cell trait

Early renal allograft failure due to sickle cell trait is rare. We present clinical and pathologic findings in 2 cases of early renal allograft failure associated with renal vein thrombosis and extensive erythrocyte sickling. Hemoglobin AS was identified in retrospect. In case 1, a 41-year-old female recipient of a deceased donor renal transplant developed abdominal pain and acute allograft failure on day 16, necessitating immediate nephrectomy. In case 2, the transplanted kidney in a 58-year-old female recipient was noted to be mottled blue within minutes of reperfusion. At 24 hours, the patient was oliguric; and the graft was removed. Transplant nephrectomies had diffuse enlargement with diffuse, nonhemorrhagic, cortical, and medullary necrosis. Extensive sickle vascular occlusion was evident in renal vein branches; interlobar, interlobular, and arcuate veins; vasa recta; and peritubular capillaries. The renal arteries had sickle vascular occlusion in case 1. Glomeruli had only focal sickle vascular occlusion. The erythrocytes in sickle vascular occlusion had abundant cytoplasmic filaments by electron microscopy. Acute rejection was not identified in either case. Protein C and S levels, factor V Leiden, and lupus anticoagulant assays were within normal limits. Hemoglobin analysis revealed hemoglobin S of 21.8% and 25.6%, respectively. Renal allograft necrosis with intragraft sickle crisis, characterized by extensive vascular occlusive erythrocyte sickling and prominent renal vein thrombosis, was observed in 2 patients with sickle cell trait. Occult sickle cell trait may be a risk factor for early renal allograft loss.

Everolimus with very low-exposure cyclosporine a in de novo kidney transplantation: a multicenter, randomized, controlled trial

BACKGROUND

In combination with everolimus (EVL), cyclosporine A (CsA) may be used at low exposure, so reducing the risk of renal dysfunction in renal transplant recipients (RTR). We evaluated whether higher exposure of EVL could allow a further reduction of CsA.

METHODS

De novo RTR were randomized to standard exposure EVL (C0 3-8 ng/mL) with low-concentration CsA (C2 maintenance levels 350-500 ng/mL, group A) or higher EVL exposure (C0 8-12 ng/mL) with very low-concentration CsA (C2 maintenance levels 150-300 ng/mL, group B). The primary endpoints were 6-month creatinine clearance (CrCl) and biopsy-proven acute rejection (BPAR) rate. After 6 months, patients were followed up (observational extension) to 12 months.

RESULTS

Two hundred eighty-five RTR (97% from deceased donors) were enrolled. Two patients per group died (1.4%). The 6-month death-censored graft survival was 90.2% in group A and 97.9% in group B and was unchanged at 12 months (P=0.007). There was no significant difference between groups at 6 months in CrCl (59.9 vs. 57.8 mL/min) and BPAR rates (14.7% vs. 11.9%) and also at 12 months (CrCl 62.5+/-20.7 vs. 61.3+/-22.0 mL/min, BPAR 14.7% vs. 14.1%). No significant differences were seen in treated acute rejections, steroid-resistant acute rejections, treatment failures, or delayed graft function, although there was a trend to better results in group B.

CONCLUSIONS

EVL given at higher exposure for 6 months plus very low CsA concentration may obtain low acute rejection rate and good graft survival in De novo renal transplantation. However, there was no difference between groups in CrCl.

Venous Graft Thrombosis in Patients on Peritoneal Dialysis Before Transplantation

BACKGROUND

It has been described that patients on peritoneal dialysis (PD) suffer from thrombotic events (vascular access, deep venous thrombosis, and graft thrombosis) more frequently after transplantation than other recipients. We analyzed the incidence of allograft thrombosis among patients transplanted in a 6-year period (January 1, 2000, to December 31, 2005) to identify etiological factors, such as inherited thrombophilia.

MATERIALS AND METHODS

We performed 197 renal transplants in 189 patients, including 115 who had been on hemodialysis (HD), 44 on PD, and 30 preemptive. We recorded immunological and demographic data, studied graft and patient survivals, and evaluated the hypercoagulable state of those who experienced graft thrombosis.

RESULTS

The mean age of the patients at transplantation was 49 years. There were no demographic or immunological differences between the three groups of patients, except for the number of previous blood transfusions and panel reactive antibodies (PRA) levels. Forty-seven grafts were lost in the first year; 14 suffered venous thrombosis, and there were 10 acute rejection epidoses (ARE), 7 death-censored graft failures, 3 chronic allograft nephropathies (CAN), 6 primary nonfunctions, 5 removed due to infection, 1 primary disease relapse, and 1 hemolytic-uremic syndrome. Of the 14 cases of thrombosis in 12 patients, 10 had been on PD and 4 on HD immediately before transplant. One-year graft and patient survivals were similar: 74% HD, 68% PD, 86% preemptive, and 93% HD, 95% PD, and 96% preemptive, respectively. The hypercoagulable state showed inherited thrombophilia patterns in some cases, but most of them were normal.

CONCLUSION

Renal graft thrombosis was responsible for graft lost in PD patients within the first year, while in the HD group it was ARE and in the preemptive cohort, death with a functioning graft. The hypercoagulable state pretransplant should be more accurately studied to identify thrombotic factors other than those which are inherited.

Bleeding and Thrombosis in High-Risk Renal Transplantation Candidates Using Heparin

BACKGROUND

Heparin can reduce the risk of renal artery/vein thrombosis in renal transplant patients with hypercoagulable states (HCS), but is associated with a high bleeding risk. Little is known about risk factors for this bleeding risk or the optimal anticoagulation target.

OBJECTIVE

To determine factors associated with this bleeding risk and determine the optimal partial thromboplastin time (PTT) ratio.

METHODS

We retrospectively reviewed medical records of consecutive adult renal transplant recipients administered heparin for perioperative renal thrombosis prevention (1998–2002).

RESULTS

Twenty-eight (3.86%) of 725 consecutive renal transplant recipients received heparin to prevent renal thrombosis. Eighteen patients (64.3%) had clinically important bleeding (14 major bleeding). Patients with and without bleeding were similar in baseline demographic characteristics and overall mean PTT. Bleeding occurred at a mean PTT ratio of 2.5 ± 1, higher than the overall mean in bleeders and nonbleeders (p = 0.001). Among postoperative characteristics, higher maximum PTT (p = 0.052) and prolonged surgical antibiotic prophylaxis (p = 0.053), particularly with cefotetan (p = 0.091), trended toward a significant association with bleeding. Two renal thrombotic episodes occurred, both at PTT ratios <1.5. A PTT ratio of 1.5–1.9 resulted in no thrombosis and ≤4.2% bleeding.

CONCLUSIONS

The benefits and risks of therapeutic heparin anticoagulation in renal transplant patients with HCSs were confirmed. Higher PTTs and cefotetan antibiotic surgical prophylaxis could contribute to bleeding. The optimal PTT ratio appeared to be 1.5–1.9 to prevent thrombosis and limit bleeding risk.

Prothrombotic disorders in uremic type-1 diabetics undergoing simultaneous pancreas and kidney transplantation

BACKGROUND

Although prothrombotic disorders (PTD) are known to increase the risk of graft failure in kidney transplantation only, there are no data on PTD in simultaneous pancreas and kidney transplantation (SPK).

METHODS

Forty-seven SPK performed between September 2000 and July 2002 underwent routine screening for PTD. Data were retrospectively analyzed in view of complications (relaparotomy, graft thrombosis, pancreatitis, rejection) and graft function (HbA1c, serum creatinine) 3 months posttransplantation.

RESULTS

Twenty-five of forty-seven (53.2%) patients had 30 PTDs. Homozygous mutations of the MTHFR gene (C677T) were found in six, factor-V Leiden mutation (homo- or heterozygous G1691A) in seven, and prothrombin mutation (20210A) in one patient (group 1). Group 2 consists of deficiencies of protein C (n=1), of protein S (n=12), of antithrombin (n=1), and antiphospholipid syndromes (n=2). Overall, PTD had no influence on graft thrombosis (P=0.36) or rejection (P=0.56). In patients with homozygous mutations, relaparotomies were more often necessary than in patients without mutations (42.9% vs. 11.8%, P=0.046). In group 1, there was a trend toward a higher incidence of graft pancreatitis than in patients without mutations (38.5% vs. 14.7%, P=0.075). Three months posttransplantation, HbA1c was 6.0% in patients with and 5.5% in patients without PTD (P=0.023). With regard to serum creatinine, no significant differences were observed.

CONCLUSION

PTD are frequent in type-1 diabetics receiving SPK and may have a role in relaparotomies, graft pancreatitis, and pancreas graft function.

Management of thrombophilia in renal transplant patients

Renal allograft recipients with thrombophilia (a hypercoagulable state) are at higher risk for early allograft loss. Following an episode of allograft renal vein thrombosis in a patient subsequently diagnosed with protein C deficiency, we adopted universal screening for hypercoagulable risk factors. Patients with a history of a thromboembolic event underwent laboratory screening for thrombophilia. Eight patients with a defined hypercoagulable disorder or a strong clinical history of thrombosis even in the absence of hematologic abnormalities were treated with anticoagulation following renal transplantation. We reviewed the outcomes of these eight patients and all renal transplant recipients at our center who developed thrombotic complications after renal transplantation. Since the introduction of universal screening for hypercoagulable risk factors, 235 consecutive transplants were performed without allograft thrombosis. Eight patients with evidence of thrombophilia, recognized before renal transplantation, received perioperative heparin and postoperative oral anticoagulation. Two of these eight patients developed perinephric hematomas requiring evacuation, blood transfusion, and temporary withholding of anticoagulation. Of interest, two of the remaining 227 patients, not identified with thrombophilia before surgery, developed thrombotic complications after renal transplantation. A hypercoagulable disorder was subsequently documented in each. Identifying patients with thrombophilia before transplantation and defining their management presents many challenges. The risk of allograft thrombosis must be weighed against the risk of perioperative bleeding and the need for long-term anticoagulation. Recommendations for managing thrombophilia in renal transplant recipients are suggested based on our experience and review of the literature.

Five preventable causes of kidney graft loss in the 1990s: a single-center analysis

BACKGROUND

Despite improvements in immunosuppressive protocols and patient care, kidney allografts continue to fail. We studied causes of graft loss for primary kidney transplants in the 1990s to determine major causes and potential interventions.

METHODS

Causes of graft loss were reviewed for 1467 primary kidney transplants done at our institution between January 1, 1990, and December 31, 1999. Graft loss for that entire population was studied and then the causes of loss selectively examined at <1 year, 1 to 5 years, and>5 years post-transplant. Finally, causes of loss in the 1990s versus the 1980s were compared.

RESULTS

Five major causes of graft loss were noted in the 1990s: thrombosis, acute rejection (either alone or combined with delayed graft function or infection), chronic rejection, death with function, and noncompliance. In the first year post-transplant, thrombosis (25%) and death with function (41%) were the major causes of graft loss. After the first year, chronic rejection and death with function predominated. For recipients dying with graft function, cardiovascular disease was the major cause of death.

CONCLUSIONS

This study identified the five major causes of kidney graft loss in the 1990s. Different interventions are required to decrease loss from each of these causes. Future research needs to be directed at such interventions.

Renal allograft loss due to proximal extension of ileofemoral deep venous thrombosis

Renal allograft recipients with thrombophilic (hypercoagulable) states are at higher risk for early allograft loss. Presumably, the combination of endothelial injury at surgery and thrombophilia predisposes to arterial or venous thrombosis. Of 270 consecutive renal transplants at our center one allograft failed secondary to renovascular thrombosis. At exploration the iliac and renal veins were thrombosed. Thrombectomy and re-implantation were attempted, but unsuccessful. Also noted at surgery was extensive clot in the femoral vein that could not be removed by embolectomy catheters. Post-operatively, a Doppler ultrasound confirmed the presence of extensive deep venous thrombosis (DVT) in the femoral and popliteal veins. The adherent nature of this clot, the extent of clot found less than 12 h after renal transplantation and the absence of leg edema suggested that the DVT existed prior to surgery. This case demonstrates that a pre-existing, asymptomatic DVT can precipitate allograft thrombosis and highlights the importance of diagnosing thrombophilia in patients undergoing renal transplantation. Current practices in our unit have evolved to include screening for thrombophilia in all patients with a suggestive history. As thrombophilic states are increasingly appreciated in the end-stage renal disease population, effective management of these patients while on hemodialysis and at the time of renal transplantation presents an ongoing challenge.

Segmental infarction with graft dysfunction: an emerging syndrome in renal transplantation?

BACKGROUND

Segmental allograft infarction is a poorly characterized complication following renal transplantation. The present study was undertaken with the goal of defining the incidence, clinical characteristics, pathogenesis, and prognosis of this entity.

METHODS

A retrospective study was performed, reviewing the renal scans performed on all renal transplant recipients at our institution, from January 1997 to January 2000. Segmental infarction was diagnosed on the basis of a significant elevation in lactate dehydrogenase (>500 U/l) together with a photopenic perfusion defect. In these patients, graft characteristics, operative details, clinical course, and long-term outcomes were evaluated.

RESULTS

Segmental infarction was identified in 13 of 277 consecutive renal transplant recipients (4.7%). In nine recipients the onset of infarction occurred within 24 h after transplantation. All received marginal grafts, and in five recipients the transplant operation was complicated by major blood loss. Eight of these recipients exhibited primary non-function, or developed dialysis-dependent renal failure after the onset of infarction. In four patients, the onset of infarction occurred after 24 h (35 h to 10 days). One recipient demonstrated primary non-function, and renal function deteriorated after the onset of infarction in the remaining three. Overall, long-term graft function was impaired. Two allografts never functioned, and six recipients had nadir creatinine clearances below 60 ml/min.

CONCLUSIONS

The pathogenesis of segmental infarction appears to be multi-factorial, reflecting the combination of an initiating anatomic lesion and potentiating thrombogenic milieu. Segmental infarction typically occurs in the early postoperative period, and prompt diagnosis is difficult to obtain. In view of this, prophylactic heparin may be warranted for those at highest risk. There was no correlation between the infarct area and the graft function, and the long-term graft function is compromised out of proportion to the extent of parenchymal loss. This finding highlights the role of predisposing factors, particularly marginal graft quality, in determining the functional outcome. Segmental infarction may be more frequently encountered as cadaveric organ shortages encourage greater use of marginal donor kidneys.