Venous thromboembolism in end-stage renal disease

Pulmonary embolism in an ESRD patient following minimal venotomy and milking for salvage of dysfunctional autogenous arteriovenous fistula

Pulmonary embolism can be a complication following an attempted salvage of a dysfuctional arteriovenous fistula (AVF). We report a case of bilateral pulmonary embolism in a patient with underlying pericardial effusion who, following minimal venotomy and milking of the AVF, developed sudden and significant respiratory distress, and later improved.

Risk and complications of venous thromboembolism in dialysis patients

Background

Contemporary data on venous thromboembolism (VTE) risk in dialysis patients are limited. Our objective was to determine the risk and complications of VTE among incident maintenance dialysis patients.

Methods

We performed a retrospective cohort study using administrative databases. We included adult incident dialysis patients from 2004 to 2010 (n = 13 315). Dialysis patients were age- and sex-matched to individuals of the general population using a 1:4 ratio (n = 53 260). We determined the 3-year cumulative incidence and incidence rate (IR) of VTE, pulmonary embolism (PE) and deep venous thrombosis (DVT). We examined outcomes of bleeding and all-cause mortality following a VTE event among matched dialysis patients who did and did not experience a VTE. We used Cox proportional hazards regression models, stratified on matched sets, to calculate the hazard ratios (HRs) for all outcomes of interest.

Results

VTE occurred in 1114 (8.4%) dialysis patients compared with 1233 (2.3%) individuals in the general population {IR 37.1 versus 8.1 per 1000 person-years; HR 4.5 [95% confidence interval (CI) 4.1-4.9]; adjusted HR 2.9 (95% CI 2.6-3.4)}. Both components of VTE [PE and DVT; adjusted HR 4.0 (95% CI 2.9-5.6) and HR 2.8 (95% CI 2.4-3.2), respectively] occurred more frequently in dialysis patients. Compared with dialysis patients without a VTE, those with a VTE had a higher risk of bleeding [adjusted HR 2.0 (95% CI 1.3-2.9)] and all-cause mortality [adjusted HR 2.4 (95% CI 2.0-2.8)].

Conclusions

VTE is common in dialysis patients and confers a high risk of major bleeding and all-cause mortality. Thromboprophylaxis and VTE treatment studies in dialysis patients are needed.

Increased risk of deep vein thrombosis in end-stage renal disease patients

Background

Previous studies have shown that chronic kidney disease increases the risk of deep vein thrombosis (DVT). DVT is the risk of pulmonary embolism among persons with end-stage renal disease (ESRD). Information on the incidence of DVT in ESRD is limited, and no studies have been conducted in the Asian population. The aim of our study was to investigate the incidence of DVT in Asian ESRD patients by comparing with the non-ESRD patients and to identify the associated risk factors.

Methods

This study retrieved patients who were diagnosed with ESRD (ICD-9-CM codes 585 or 586) between January 1, 2004, and December 31, 2010, from the National Health Insurance Research Database in Taiwan. All ESRD patients had received a catastrophic illness card from the Ministry of Health and Welfare in Taiwan, with the major illness identified as ESRD. Patients who had DVT before the index date or who had incomplete records were excluded from the analysis. A total of 4865 ESRD patients were enrolled. There are 3564 ESRD patients included after exclusion of patients with previous DVT and patients with incomplete records. The control subjects were randomly selected as the patients without ESRD by matching study subjects according to age (±3 years), gender, and the year of admission at a 2:1 ratio from the same dataset.

Results

The incidence rate of DVT was substantially higher in the ESRD group than in the without-ESRD group (20.9 vs. 1.46 per 10^4 person-years). The adjusted hazard ratio (aHR 13.92; 95% CI 9.25–20.95) of DVT for the ESRD patients was 13.92 times that for the non-ESRD patients. ESRD patients older than 50 years had a higher risk of DVT (aHR 1.65; 95% CI 1.13–2.40; P = 0.01). Hyperlipidemia was significantly associated with an increased risk of DVT (aHR 1.73; 95% CI 1.08–2.78; P = 0.02). ESRD patients with three or more comorbidities were substantially more likely to have DVT (aHR 1.45; 95% CI 1.03–2.03; P = 0.03).

Conclusions

ESRD patients had a higher risk of DVT than non-ESRD patients. Among the ESRD patients, being older than 50 years and having dyslipidemia increased the risk of DVT.

Hemodialysis Arteriovenous Fistulas: A Nineteenth Century View of a Twenty First Century Problem

This is a literature review which approaches the problem of successful use of arteriovenous fistulas for dialysis within the construct of Virchow's triad. By organizing the literature with regard to Virchow's concepts of blood flow, vascular injury, and thrombophilia an improved understanding arteriovenous fistula placement, maintenance and repair can be obtained. This process is designed to increase understanding and options for treatment by looking at this problem and using scientific knowledge gained in cardiology, oncology and vascular surgery medicine. Future approaches to fistulas will hopefully be a multifaceted and based in cellular pathophysiology as well as surgical and radiologic interventions and repairs.

Association of Erythropoietin Dose and Route of Administration with Clinical Outcomes for Patients on Hemodialysis in the United States

BACKGROUND AND OBJECTIVES

Recombinant human erythropoietin (epoetin) is used routinely to increase blood hemoglobin levels in patients with ESRD and anemia. Although lower doses of epoetin are required to achieve equivalent hemoglobin responses when administered subcutaneously rather than intravenously, standard practice has been to administer epoetin to patients on hemodialysis intravenously. Randomized trials of alternative epoetin treatment regimens in patients with kidney failure have shown that risks of cardiovascular complications and death are related to the dose levels of epoetin used. Therefore, given the dose-sparing advantages of subcutaneous epoetin administration, the possibility that treatment of patients on hemodialysis with subcutaneous epoetin might be associated with more favorable outcomes compared with intravenous treatment was investigated.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A retrospective cohort study of 62,710 adult patients on hemodialysis treated with either intravenous or subcutaneous epoetin-α and enrolled in the Centers for Medicare and Medicaid Services ESRD Clinical Performance Measures Project from 1997 to 2005 was carried out. Risks of death and/or hospitalization for cardiovascular complications (adverse composite event outcomes) during 2 years of follow-up were determined in relationship to epoetin dose and route of administration (intravenous versus subcutaneous) by multivariate Cox proportional hazard modeling adjusted for demographics and clinical parameters.

RESULTS

Epoetin doses used to achieve equivalent hemoglobin responses in study patients were, on average, 25% higher when epoetin was administered intravenously rather than subcutaneously (as expected). Moreover, adverse composite event outcomes were found to be significantly more likely to occur during follow-up for patients on hemodialysis managed with intravenous rather than subcutaneous epoetin (adjusted hazard ratio for adverse events within 1 year [intravenous versus subcutaneous] was 1.11 [95% confidence interval, 1.04 to 1.18]).

CONCLUSIONS

This study finds that treatment of patients on hemodialysis with subcutaneous epoetin is associated with more favorable clinical outcomes than those associated with intravenous epoetin treatment.

Fatal pulmonary embolism after hemodialysis vascular access declotting

Patient: Male, 59

Final Diagnosis: Pulmonary embolism

Symptoms: Cardiac arrest • chest pain • dyspnea

Medication: —

Clinical Procedure: Angioplasty

Specialty: Nephrology

Association of Nephropathic Cystinosis and Pseudotumor Cerebri with Bilateral Duane Syndrome Type I

A 15-year-old girl, a known case of nephropathic cystinosis with a history of kidney transplantation, presented for evaluation of lid drooping in lateral gaze and a recent-onset headache. Examination of ocular movements showed bilateral limitation of abduction combined with narrowing of palpebral fissure in adduction. Deposition of polychromatic crystals in the conjunctiva and corneal stroma of both eyes was evident. Both optic discs were oedematous and intracranial pressure was 270 mm CSF, which responded to oral acetazolamide. The patient developed metabolic imbalances and multiple organ failure, from which she expired 3 months after presentation.

Functional investigation of a venous thromboembolism GWAS signal in a promoter region of coagulation factor XI gene

Coagulation factor XI (FXI) is essential for normal function of the intrinsic pathway of blood coagulation. A nucleotide variant (rs3756008) in the promoter region of the FXI gene was recently reported for association with venous thromboembolism. This study aimed to examine promoter activity of the rs3756008 or other variants linked with it. Luciferase assay was analyzed with minigenes including haplotypes (AA with frequency of 0.62 and TG with frequency of 0.38) of 2 completely linked nucleotide variants (rs3756008 and rs3756009) in 5'-upstream region of the FXI gene. While their expression did not differ in hepatic cell (P > 0.05), the major haplotype (AA) made a significantly more expression (P < 0.05) than the minor haplotype (TG) in human embryonic kidney 293 cells. Further luciferase analysis with additional haplotypes (artificial; TA, AG) revealed that the large expression was caused by the major allele of rs3756008 (P < 0.05), but not by that of rs3756009 (P > 0.05). We suggested that the minor allele of rs3756008 in the promoter of FXI gene could reduce its expression in kidney.

Single nucleotide variants in the protein C pathway and mortality in dialysis patients

BACKGROUND

The protein C pathway plays an important role in the maintenance of endothelial barrier function and in the inflammatory and coagulant processes that are characteristic of patients on dialysis. We investigated whether common single nucleotide variants (SNV) in genes encoding protein C pathway components were associated with all-cause 5 years mortality risk in dialysis patients.

METHODS

Single nucleotides variants in the factor V gene (F5 rs6025; factor V Leiden), the thrombomodulin gene (THBD rs1042580), the protein C gene (PROC rs1799808 and 1799809) and the endothelial protein C receptor gene (PROCR rs867186, rs2069951, and rs2069952) were genotyped in 1070 dialysis patients from the NEtherlands COoperative Study on the Adequacy of Dialysis (NECOSAD) cohort) and in 1243 dialysis patients from the German 4D cohort.

RESULTS

Factor V Leiden was associated with a 1.5-fold (95% CI 1.1-1.9) increased 5-year all-cause mortality risk and carriers of the AG/GG genotypes of the PROC rs1799809 had a 1.2-fold (95% CI 1.0-1.4) increased 5-year all-cause mortality risk. The other SNVs in THBD, PROC, and PROCR were not associated with 5-years mortality.

CONCLUSION

Our study suggests that factor V Leiden and PROC rs1799809 contributes to an increased mortality risk in dialysis patients.

Elevated levels of procoagulant plasma microvesicles in dialysis patients

Cardiovascular (CV) death remains the largest cause of mortality in dialysis patients, unexplained by traditional risk factors. Endothelial microvesicles (EMVs) are elevated in patients with traditional CV risk factors and acute coronary syndromes while platelet MVs (PMVs) are associated with atherosclerotic disease states. This study compared relative concentrations of circulating MVs from endothelial cells and platelets in two groups of dialysis patients and matched controls and investigated their relative thromboembolic risk. MVs were isolated from the blood of 20 haemodialysis (HD), 17 peritoneal dialysis (PD) patients and 20 matched controls. Relative concentrations of EMVs (CD144(+ ve)) and PMVs (CD42b(+ ve)) were measured by Western blotting and total MV concentrations were measured using nanoparticle-tracking analysis. The ability to support thrombin generation was measured by reconstituting the MVs in normal plasma, using the Continuous Automated Thrombogram assay triggered with 1µM tissue factor. The total concentration of MVs as well as the measured sub-types was higher in both patient groups compared to controls (p<0.05). MVs from HD and PD patients were able to generate more thrombin than the controls, with higher peak thrombin, and endogenous thrombin potential levels (p<0.02). However there were no differences in either the relative quantity or activity of MVs between the two patient groups (p>0.3). Dialysis patients have higher levels of circulating procoagulant MVs than healthy controls. This may represent a novel and potentially modifiable mediator or predictor of occlusive cardiovascular events in these patients.

Pulmonary embolism in patients with CKD and ESRD

BACKGROUND AND OBJECTIVES

CKD and ESRD are growing burdens. It is unclear whether these conditions affect pulmonary embolism (PE) risk, given that they affect both procoagulant and anticoagulant factors. This study examined the frequency and associated outcomes of PE in CKD and ESRD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Healthcare Cost and Utilization Project's Nationwide Inpatient Sample was used to estimate the frequency and outcomes of PE in adults with CKD and ESRD. Hospitalizations for the principal diagnosis of PE and presence of CKD or ESRD were identified using International Classification of Diseases, Ninth Revision codes. Data from the annual US Census and US Renal Data System reports were used to calculate the number of adults with CKD, ESRD, and normal kidney function (NKF) as well as the annual incidence of PE in each group. Logistic regression modeling was used to compare in-hospital mortality among persons admitted for PE who had ESRD or CKD to those without these conditions.

RESULTS

The annual frequency of PE was 527 per 100,000, 204 per 100,000, and 66 per 100,000 persons with ESRD, CKD, and NKF, respectively. In-hospital mortality was higher for persons with ESRD and CKD (P<0.001) compared with persons with NKF. Median length of stay was longer by 1 day in CKD and 2 days in ESRD than among those with NKF.

CONCLUSIONS

Persons with CKD and ESRD are more likely to have PE than persons with NKF. Once they have PE, they are more likely to die in the hospital.

Erythropoietin update 2011

Traditionally, erythropoietin (EPO) is described as a hematopoietic cytokine, regulating proliferation and differentiation and survival of the erythroid progenitors. The recent finding of new sites of EPO production and the wide spread distribution of EPO receptors (EPO-R) on endothelial cells, cardiomyocytes, renal cells as well as the central and peripheral nervous system raised the possibility that EPO may exert pleiotropic actions on several targets. Indeed studies (mainly preclinical) have documented protective, non-hematopoietic, abilities of EPO in a variety of tissue. However, the data obtained from clinical studies are more skeptical about these properties. This article provides a comprehensive overview of EPO and its derivatives.

Pulmonary embolism following successful thrombectomy of an arteriovenous dialysis fistula

A hemodialysis patient was diagnosed with pulmonary embolism, shortly after successful thrombectomy of an autogenous arteriovenous fistula. Diagnostic testing revealed no alternative source for thromboembolism. Increased recognition of hypercoagulability as a common consequence of end-stage renal disease would suggest that dialysis patients would be at risk for thromboembolic events. A fully developed dialysis fistula may have sufficient luminal diameter to harbor subclinical or clinically significant venous thrombi. Clinicians should be alert to the possibility of venous emboli after fistula manipulation.

What is so bad about a hemoglobin level of 12 to 13 g/dL for chronic kidney disease patients anyway?

Randomized controlled trials (RCTs) clearly indicate a possible cardiovascular morbidity and mortality risk when deliberately targeting a normal hemoglobin (Hb) concentration of 13 to 15 g/dL. By contrast, observational studies point to greater hospitalization and mortality at Hb levels <11 g/dL. There are no direct data to help us determine where, within this broad range, the optimal Hb lies. In RCTs and observational studies, significant confounding from the interrelationships of anemia and epoetin resistance occurs in patients with a serious illness. Patients with comorbidities such as malnutrition and inflammatory processes are more resistant to epoetin and, invariably, require greater cumulative epoetin doses. The effect of a higher erythropoiesis-stimulating agent (ESA) dose on increasing mortality has been noted repeatedly in post hoc analyses of RCTs. It is therefore too simplistic to solely attribute the outcomes achieved in RCTs to "target Hb." We discuss various mechanisms for potential harm at higher Hb levels as opposed to those that may be obtained from higher epoetin doses. For the individual patient, the therapeutic decision should center on what Hb is most appropriate at a "safe" ESA dose. Consequently, an Hb of 12 to 13 g/dL may be totally appropriate in some patient populations.

Beyond anemia: the clinical impact of the physiologic effects of erythropoietin

Although we have known that oxygen tension affects erythrocyte production since the 19th century, we have only recently begun to understand many subtleties of erythropoietin (EPO) physiology. EPO administration has allowed hundreds of thousands of patients to avoid transfusions. With the beneficial effects so apparent a detailed understanding of the full clinical physiology of this plasma factor seemed less important. However, the unanticipated increase in mortality found in recent randomized studies is prompting a reassessment of this view. We will review what is known about the physiology of this plasma factor that, it is now clear, is more than just an erythrocyte production factor.

Venous thromboembolism prophylaxis in emergency department admissions

BACKGROUND

Guidelines for venous thromboembolism prophylaxis exist, yet prophylaxis is underutilized and inadequately studied in the context of emergency department admissions.

OBJECTIVE

This study aimed to measure the rate of venous thromboembolism prophylaxis in emergency department hospitalizations.

DESIGN

Prospective observational study.

SETTING

Urban, teaching hospital.

PATIENTS

Adult emergency department admissions

INTERVENTION

Alternating admissions through the emergency department over 1 month were reviewed. Exclusion criteria were: requiring full anticoagulation, hemodialysis, length of stay less than 2 days, psychiatric admission, and primary physician declined review. An established risk assessment tool classified thromboembolism risk. Appropriate prophylaxis was defined as currently accepted medical or mechanical prophylaxis if in need or no prophylaxis if not indicated.

MEASUREMENTS

Factors associated with prophylaxis were considered significant if P < .05.

RESULTS

Of 254 patients, 201 (79%) had indications for prophylaxis, of whom 65 (32%) received it. Seventy-eight percent of prophylaxis orders were written in the first day of hospitalization. Factors related to increased use of prophylaxis included use of standard order sets (OR = 3, P < .009) and increased risk of venous thromboembolism (P < .0001). Factors related to underuse included primary cardiovascular diagnosis (OR = 0.18, P < .0001) and age (OR = 0.97, P < .0001). Eighteen of 26 patients admitted for whom standard order sets were used (69%) received appropriate prophylaxis (P = .01).

CONCLUSIONS

Patients admitted through the emergency department are at high risk of venous thromboembolism. Despite this, venous thromboembolism prophylaxis is underutilized and rarely started after the first day of hospitalization. Use of admission standard order sets on admission from the emergency department may increase thromboembolic prophylaxis.

Venous thromboembolism prevention in the acutely ill medical patient: a review of the literature and focus on special patient populations

Although venous thromboembolism (VTE) is a major public health problem, until recently, our understanding of the risk of VTE in hospitalized acutely ill medical patients has been incomplete. Fortunately, over the past 5 years, there has been an increasing body of literature that highlights the risk of VTE in the nonsurgical patient, identifies unique patient-risk factors, and defines adequate preventative measures. This review highlights the current literature with regard to epidemiology of VTE in hospitalized medical patients and the risk-stratification of these patients and deals with optimal preventative regimens and prevention strategies in special patient groups.

Anticoagulant use in patients with chronic renal impairment

Patients with renal failure have an increased risk of both thrombotic and bleeding complications. A number of antithrombotic drugs undergo renal clearance. Therefore, estimation of renal function is necessary when prescribing these drugs to patients with renal dysfunction. Pharmacokinetic and clinical data in patients with chronic renal impairment are limited for several anticoagulants, and adequate administration information is often absent. Dose adjustment of anticoagulants may be indicated when the creatinine clearance falls below 30 mL/min. Unfractionated heparin, argatroban, and vitamin K antagonists generally do not require dose adjustment with renal dysfunction. However, smaller doses of warfarin may be required to achieve a particular target international normalized ratio. Close monitoring of anticoagulation is recommended when argatroban or high doses of unfractionated heparin are administered in patients with severe chronic renal impairment. Low-molecular weight heparins, danaparoid sodium, hirudins, and bivalirudin all undergo renal clearance. Lower doses and closer anticoagulation monitoring may be advisable when these agents are used in patients with chronic renal failure. We recommend that fondaparinux sodium and ximelagatran (not yet licensed) be avoided in the presence of severe renal impairment and be used with caution in patients with moderate renal dysfunction. While acknowledging the lack of pharmacokinetic data, this review provides specific recommendations for the use of anticoagulants in patients with chronic renal impairment.

Idiopathic intracranial hypertension in cystinosis

OBJECTIVES

To report a high frequency of idiopathic intracranial hypertension (IIH) in patients with cystinosis and to speculate on the relationship between these two disorders.

STUDY DESIGN

Retrospective case series and review of the literature regarding risk factors for the development of IIH in cystinosis.

RESULTS

Eight patients with cystinosis had documented papilledema, normal neuroimaging of the brain, cerebrospinal fluid (CSF) opening pressure greater than 200 mm of H2O, and normal CSF composition. No common medication, condition, or disease except cystinosis was found in these persons. Six of the patients had received prednisone, growth hormone, cyclosporine, oral contraceptives, vitamin D, or levothyroxine at the time of onset of IIH. Five patients had previous renal transplants.

CONCLUSION

No single risk factor for the development of IIH linked IIH to cystinosis in our patients. However, thrombosis susceptibility as a result of renal disease or impaired CSF reabsorption in the arachnoid villi as a result of cystine deposition might lead to the development of IIH in cystinosis.

Thrombosis in end-stage renal disease

Although renal failure has classically been associated with a bleeding tendency, thrombotic events are common among patients with end-stage renal disease (ESRD). A variety of thrombosis-favoring hematologic alterations have been demonstrated in these patients. In addition, "nontraditional" risk factors for thrombosis, such as hyperhomocysteinemia, endothelial dysfunction, inflammation, and malnutrition, are present in a significant proportion of chronic dialysis patients. Hemodialysis (HD) vascular access thrombosis, ischemic heart disease, and renal allograft thrombosis are well-recognized complications in these patients. Deep venous thrombosis and pulmonary embolism are viewed as rare in chronic dialysis patients, but recent studies suggest that this perception should be reconsidered. Several ESRD treatment factors such as recombinant erythropoietin (EPO) administration, dialyzer bioincompatibility, and calcineurin inhibitor administration may have prothrombotic effects. In this article we review the pathogenesis and clinical manifestations of thrombosis in ESRD and evaluate the evidence that chronic renal failure or its management predisposes to thrombotic events.

Atrial fibrillation in chronic dialysis patients in the United States: risk factors for hospitalization and mortality

BACKGROUND

The incidence and risk factors for hospitalized atrial fibrillation have not been previously assessed in a national population of dialysis patients.

METHODS

We analyzed the United States Renal Data System (USRDS) Dialysis Morbidity and Mortality Study (DMMS) Wave II in a historical cohort study of hospitalized atrial fibrillation. Data from 3374 patients who started dialysis in 1996 with valid follow-up times were available for analysis, censored at the time of renal transplantation and followed until November 2000. Cox Regression analysis was used to model factors associated with time to first hospitalization for atrial fibrillation (ICD9 code 427.31x) adjusted for comorbidities, demographic factors, baseline laboratory values, blood pressures, dialysis modality, and cardioprotective medications.

RESULTS

The incidence density of atrial fibrillation was 12.5/1000 person years. Factors associated with atrial fibrillation were older age (> or = 71 years vs. <48 years), extremes (both high and low) of pre-dialysis systolic blood pressure, dialysis modality (hemodialysis vs. peritoneal dialysis), and digoxin use. Baseline use of coumadin was associated with reduced mortality in patients later hospitalized for atrial fibrillation.

CONCLUSIONS

Dialysis patients had a high incidence of atrial fibrillation. This risk was largely segregated among those with established risk factors for atrial fibrillation, and hemodialysis patients. Use of coumadin was associated with improved survival among patients later hospitalized for atrial fibrillation.

Chronic dialysis patients have high risk for pulmonary embolism

Pulmonary embolism has been considered uncommon in chronic dialysis patients, but has not been adequately studied in a large population. In the US Renal Data System (USRDS), 76,718 patients presenting with end-stage renal disease (ESRD) between January 1, 1996, and December 31, 1996, were analyzed in an historical cohort study. The outcome was hospitalizations with a primary discharge diagnosis of pulmonary embolism (International Classification of Diseases, Ninth Revision code 415.1x) occurring within 1 year of the first ESRD treatment and excluding those occurring after renal transplantation. For dialysis patients, hospitalization rates for pulmonary embolism were obtained from the hospitalization section of the 1999 USRDS. For the general population, hospitalization rates for pulmonary embolism were obtained from the National Hospital Discharge Survey for 1996. Comorbidities from the Medical Evidence Form (Centers for Medicare and Medicaid Services, previously known as the Health Care Financing Administration; form 2728) were used to generate approximated stratified models of adjusted incidence ratios for pulmonary embolism (comorbidities could not be stratified for the general population). In 1996, the overall incidence rate of pulmonary embolism was 149.90/100,000 dialysis patients compared with 24.62/100,000 persons in the US population, with an age-adjusted incidence ratio of 2.34 in dialysis patients. Younger dialysis patients had the greatest relative risk for pulmonary embolism. The age-adjusted incidence ratio of pulmonary embolism after excluding dialysis patients with known risk factors for pulmonary embolism was 2.11. Ninety-five percent confidence intervals for all age categories in both models were statistically significant. Chronic dialysis patients have high risk for pulmonary embolism, independent of comorbidity.

Factor V Leiden mutation: potential thrombogenic role in renal vein, dialysis graft and transplant vascular thrombosis

Factor V is an important blood coagulation factor, the procoagulatory activity of which is inhibited by activated protein C. The factor V Leiden mutation is due to a single base-pair change (G1691A), which alters the initial cleavage site for activated protein C. The impaired degradation of factor V by activated protein C yields a hypercoagulable state that confers a lifelong increased risk of thrombosis in heterozygous and homozygous individuals. The factor V Leiden mutation represents the most common cause of inherited thrombophilia, and enhances the risk for venous thrombosis by approximately sevenfold. In normal Western populations, heterozygosity for the factor V Leiden mutation is present in 2-5%, whereas in patients with venous thrombosis and a family history of thrombotic disease this figure may reach 50-60%. The presence of the mutation markedly increases the risk for renal vein thrombosis, particularly in neonates. Heterozygosity for factor V Leiden mutation does not appear to be a major risk factor for dialysis access clotting. The presence of factor V Leiden mutation is most devastating in kidney transplant recipients. In these patients the mutation predisposes to renal transplant vein thrombosis and early graft loss. The risk for acute vascular rejection is also enhanced in transplant recipients who are heterozygous for the mutation. Routine screening for factor V Leiden mutation by polymerase chain reaction, and appropriate perioperative and postoperative anticoagulation after renal transplantation might be a valuable strategy to prevent thromboembolic complications in transplant recipients.