Vascular Access Thrombosis Research Articles

A randomized trial of albumin infusion to prevent intradialytic hypotension in hospitalized hypoalbuminemic patients

BackgroundIntradialytic hypotension (IDH) is a frequent complication of intermittent hemodialysis (IHD), occurring from 15 to 50% of ambulatory sessions, and is more frequent among hospitalized patients with hypoalbuminemia. IDH limits adequate fluid removal and increases the risk for vascular access thrombosis, early hemodialysis (HD) termination, and mortality. Albumin infusion before and during therapy has been used for treating IDH with the varying results. We evaluated the efficacy of albumin infusion in preventing IDH during IHD in hypoalbuminemic inpatients.MethodsA randomized, crossover trial was performed in 65 AKI or ESKD patients with hypoalbuminemia (albumin < 3 g/dl) who required HD during hospitalization. Patients were randomized to receive 100 ml of either 0.9%sodium chloride or 25% albumin intravenously at the initiation of each dialysis. These two solutions were alternated for up to six sessions. Patients' vital signs and ultrafiltration removal rate were recorded every 15 to 30 min during dialysis. IDH was assessed by different definitions reported in the literature. All symptoms associated with a noted hypotensive event as well as interventions during the dialysis were recorded.ResultsSixty-five patients were submitted to 249 sessions; the mean age was 58 (pm 12), and 46 (70%) were male with a mean weight of 76 (pm 18) kg. The presence of IDH was lower during albumin sessions based on all definitions. The hypotension risk was significantly decreased based on the Kidney Disease Outcomes Quality Initiative definition; (15% with NS vs. 7% with albumin, p = 0.002). The lowest intradialytic SBP was significantly worse in patients who received 0.9% sodium chloride than albumin (NS 83 vs. albumin 90 mmHg, p = 0.035). Overall ultrafiltration rate was significantly higher in the albumin therapies [NS − 8.25 ml/kg/h (− 11.18 5.80) vs. 8.27 ml/kg/h (− 12.22 to 5.53) with albumin, p = 0.011].ConclusionIn hypoalbuminemic patients who need HD, albumin administration before the dialysis results in fewer episodes of hypotension and improves fluid removal. Albumin infusion may be of benefit to improve the safety of HD and achievement of fluid balance in these high-risk patients.ClinicalTrials.gov Identifier: NCT04522635

Surgical treatment of true aneurysms of permanent vascular access

Analyzed herein are the results of surgical treatment of true diffuse aneurysms of the permanent vascular access in 44 patients. Of these, there were 29 men and 15 women, mean age 48.1±2.3 years (19-78 years). The average time having elapsed since the formation of the native access was 109.4±9.5 months (12-276, median - 108 months). The indications for surgical treatment were as follows: haemorrhage including recurrent bleedings (3), thrombosis of the permanent vascular access (26), its dysfunction (5), high flow syndrome (3), large-size aneurysm with disordered function of the limb, pain syndrome or a pronounced cosmetic defect (7). In 14 cases, reconstruction was not performed. We carried out ligating operations, in some instances with partial removal of the aneurysm and establishing a new vascular access. 3 patients underwent resection of the aneurysm with replacement by a graft. In the remote period 1 patient at 46 months developed infection of the prosthesis, resulting in loss of the access. Follow up of the remaining 2 patients demonstrated satisfactory function of the vascular access at 6 and 60 months. 16 patients were subjected to total plasty of the aneurysm using autotissues. On a cylindrical template measuring 6 mm in diameter after dissection of excessive tissues along the posterior wall of the vein, an uninterrupted suture was formed followed by placing the formed transplant into a new bed. 11 patients underwent the operation according to the analogous technique, but the formed autotransplant was reinforced with a thin-wall exoprosthesis made of polytetrafluoroethylene up to 0.2-mm thick and 10 mm in diameter ('Ecoflon'). Two (12.5%) of 16 patients subjected to reconstruction of the aneurysm without reinforcement developed haemorrhage in the early postoperative period, and one developed thrombosis thus resulting in loss of the access. In-hospital patency amounted to 81.3%. In plasty with reinforcement, there were no complications in the early postoperative period. Long-term primary patency after total plasty without reinforcement at 1, 3, and 5 years amounted to 68.2±11.8%, 56.8±14.3%, and 22.7±13.7%, respectively, with secondary patency of 68.2±11.8% at the above-mentioned terms. In the majority of patients aneurysmatic transformation of the transplant occurred again in the remote period. Primary patency at 1, 3 and 4 years after plasty with reinforcement amounted to 80.8±12.2%, 80.8±12-2% and 60.6±19.8%, respectively, with the secondary patency rates of 90.9±8.7% at the above mentioned terms.

Targeting Uremic Toxins to Prevent Peripheral Vascular Complications in Chronic Kidney Disease.

Chronic kidney disease (CKD) exhibits progressive kidney dysfunction and leads to disturbed homeostasis, including accumulation of uremic toxins, activated renin-angiotensin system, and increased oxidative stress and proinflammatory cytokines. Patients with CKD are prone to developing the peripheral vascular disease (PVD), leading to poorer outcomes than those without CKD. Cumulative evidence has showed that the synergy of uremic milieu and PVD could exaggerate vascular complications such as limb ischemia, amputation, stenosis, or thrombosis of a dialysis vascular access, and increase mortality risk. The role of uremic toxins in the pathogenesis of vascular dysfunction in CKD has been investigated. Moreover, growing evidence has shown the promising role of uremic toxins as a therapeutic target for PVD in CKD. This review focused on uremic toxins in the pathophysiology, in vitro and animal models, and current novel clinical approaches in reducing the uremic toxin to prevent peripheral vascular complications in CKD patients.

Role of Inherited Thrombophilia Risk Factors in Patients with CKD-5 Receiving Haemodialysis

Background: The inherited thrombophilic mutations of the factor V gene (FVG1691A Leiden-FVL), prothrombin gene (PTG20210A), and the methylenetetrahydrofolate reductase gene C677T (MTHFR C677T) are risk factors for thromboembolic events and are related to the pathogenesis of vascular diseases. Objectives: The main objective of this study was to explore the role of these factors in the pathogenesis of chronic kidney disease (CKD) and survival of patients with CKD-5 receiving haemodialysis. Methods: A cohort of 395 patients with CKD-5 on haemodialysis, from 6 dialysis units in Crete, Greece were recruited based on their medical records and were followed for 5 years. We collected data on CKD-5 aetiology, thrombophilic gene expression, vascular access thrombosis, time of death, and causes of death. Results: The mutated genes just as prevalent in patients with CKD-5 as they were in a control group with no renal disease (p > 0.05). FVL heterozygosity was significantly more prevalent (11.4 vs. 5.7%; p = 0.036) in patients presented with CKD of unknown aetiology, compared to CKD secondary to known aetiologies. The survival of patients with CKD-5 receiving haemodialysis was not affected by the presence of any thrombophilic mutation. This held true for the whole cohort and for the cohort that included only lethal vascular events. Most patients with MTHFR C677T heterozygosity, and all patients with MTHFR C677T homozygosity, died from vascular events during the follow-up period. Conclusion: The FVL mutation may act as a risk factor for CKD. This study increases our understanding of molecular mechanisms in the pathogenesis of CKD of unknown aetiology. Τhe presence of thrombophilic mutations did not affect the overall survival of patients with CKD-5. This finding probably reflects the effect of medical care on patient outcomes.

Visit-to-visit systolic blood pressure variability associates with vascular thrombosis in hemodialysis patients

Abstract Background Blood pressure variability (BPV) is an independent risk factor for cardiovascular events and death in general population. Hemodialysis patients have higher BPV and higher vascular events than general population. However, the impact of BPV on vascular events of hemodialysis patients is not clear. Purpose To determine the association of BPV with vascular outcomes in patients on maintenance hemodialysis. Method In this prospective multi-center study, we enrolled 927 maintenance hemodialysis patients from Jan, 2017 to Dec, 2017. We used the coefficient of variation (CV) and the variance independent of mean (VIM) of predialysis systolic blood pressure (SBP) derived from the first 3 months (36 dialysis sessions) after enrollment as the metrics of BPV. Patients were prospectively followed at 3-month interval. Outcomes included death, systemic vascular thrombosis (nonfatal myocardial infarction, ischemic stroke, and acute limb ischemia), and dialysis vascular access thrombosis. Results In all, 707 subjects with at least 20 measurements were included in the analysis. Patients' mean age was 66 years and 50% of patients were male. Baseline factors associated higher BPV included diabetes, high co-morbidity scores, low albumin, high systolic and diastolic blood pressure. The mean pre-dialysis SBP CV was 10.9% and VIM was 28.9%. The median follow-up duration was 2.5 years, during which 103 deaths, 81 systemic vascular thrombosis, and 155 dialysis access thrombosis occurred. In unadjusted model, we found that the highest BPV tertile had a 52% increased risk of vascular thrombosis than the lowest BPV tertile (HR=1.52, 95% CI 1.23–1.86, P&amp;lt;0.001). After multivariable adjustment (including age, diabetes, co-morbidity score, albumin, baseline systolic and diastolic BP), this association remained statistically significant (HR=1.47, 95% CI=1.18–1.84, P=0.001). Systolic BPV was associated with either systemic vascular thrombosis (HR=1.44, 95% CI=1.08–1.93, P=0.01) or dialysis vascular access thrombosis (HR=1.55, 95% CI=1.16–1.82, P=0.001). Conclusion In the cohort of patients on maintenance hemodialysis, high pre-dialysis systolic BPV was associated a higher risk of vascular thrombosis events, both for systemic vascular thrombosis and dialysis vascular access thrombosis. Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): National Taiwan University Hsinchu Branch

Frailty is associated with vascular thrombosis events in chronic hemodialysis patients

Abstract Background Frailty is common in chronic hemodialysis patients and is associated with increased risk of mortality. In hemodialysis patients, cardiovascular disease is the most cause of mortality but the impact of frailty on cardiovascular disease remained unknown. Purpose To access if there was an association between frailty and vascular thrombotic events among chronic hemodialysis patients. Methods This is a multi-center cohort study of chronic hemodialysis patients conducted since Jan, 2018 (last follow-up in December, 2020). Baseline data were collected from medical records and hemodialysis records. Frailty was defined by the Fried's criteria, a composite construct that incorporated poor physical functioning, exhaustion/fatigue, low physical activity, and undernutrition using a self-reported questionnaire. The primary outcome was vascular thrombosis events, defined as myocardial infarction, ischemic stroke, acute or critical limb ischemia, and dialysis vascular access thrombosis. The outcomes were assessed from a prospectively-collected nationwide registration system which was updated every 3 months and verified after review of medical records or discussion with caring physicians. Results During the study period, 571 chronic hemodialysis patients were enrolled. The mean age of study participants was 66 years old (SD, 13) and 55% of them were male. A total of 247 patients (43%) were categorized as frail. At baseline, logistic regression analysis revealed that older age, female sex, diabetes, low albumin and history of stroke were independently associated with frailty. During the follow-up period (median, 18 months), 57 patients (10%) died and 182 patients (31.9%) had vascular thrombosis events, including 101 arterial thrombosis (17.7%) and 105 dialysis access thrombosis (18.4%). In the primary outcome analysis, Cox proportional hazards modeling indicated that frailty was independently associated with vascular thrombosis events (Hazard ratio [HR] 1.71, 95% confidence interval [CI] 1.132–2.597). In the secondary analysis, frailty was associated death (HR 2.25, CI 1.16–4.37), arterial thrombosis events (HR 1.92, CI 1.16–3.18), and dialysis vascular access thrombosis events (HR 1.90, CI 1.24–2.91). Conclusion Frailty phenotype is extremely common in hemodialysis patients. It is associated with mortality and vascular thrombosis events among chronic hemodialysis patients. Given its prevalence and consequence, research focus on interventions aimed to prevent or attenuate frailty in hemodialysis patients should be warranted. Funding Acknowledgement Type of funding source: Public hospital(s). Main funding source(s): Grants from National Taiwan University Hospital, Hsinchu Branch.

Plasmatic osteopontin is a predictive marker of stenosis in patients with a hemodialysis arteriovenous fistula

In spite of the guidelines for an improvement, the follow up of vascular accesses remains insufficient, due to the costs and the burden for the patients. The rate of thrombosis of vascular access reaches 10% per annum. We assumed that the plasmatic level of osteopontin (OPN), a pro-inflammatory molecule correlated with intimal hyperplasia, could be a predictive marker of stenosis in hemodialysis patients with an arteriovenous fistula (AVF), which could allow the detection of the AVFs at risk of thrombosis by a biological test.

Semiparametric mixture cure model analysis with competing risks data: Application to vascular access thrombosis data.

The article is motivated by a nephrology study in Taiwan, which enrolled hemodialysis patients who suffered from vascular access thrombosis. After treatment, some patients were cured of thrombosis, while some may experience recurrence of either type (acute or nonacute) of vascular access thrombosis. Our major interest is to estimate the cumulative incidence probability of time to the first recurrence of acute thrombosis after therapy. Since the occurrence of one type of vascular access thrombosis precludes occurrence of the other type, patients are subject to competing risks. To account for the presence of competing risks and cured patients, we develop a mixture model approach to the regression analysis of competing-risks data with a cure fraction. We make inference about the effects of factors on both the cure rate and cumulative incidence function (CIF) for a failure of interest, which are separately specified in the logistic regression model and semiparametric regression model with time-varying and time-invariant effects. Based on two-stage method, we develop novel estimation equations using the inverse probability censoring weight techniques. The asymptotic properties of the estimators are rigorously studied and the plug-in variance estimators can be obtained for constructing interval estimators. We also propose a lack-of-fit test for assessing the adequacy of the proposed model and several tests for time-varying effects. The simulation studies and vascular access thrombosis data analysis are conducted to illustrate the proposed method.

MO015HAEMODIALYSIS VASCULAR ACCESS THROMBOSIS: AN ANALYSIS OF EVENTS FROM THE PROACTIVE IV IRON THERAPY IN HAEMODIALYSIS PATIENTS (PIVOTAL) TRIAL

Abstract Background and Aims Haemodialysis vascular access thrombosis (VAT) is a common occurrence that undermines the safe and effective delivery of haemodialysis (HD) and has been associated with anaemia therapy. In the Proactive IV Iron Therapy in Haemodialysis Patients trial (PIVOTAL), proactive high-dose intravenous iron dosing was compared with reactive low-dose intravenous iron dosing. VAT was a pre-specified secondary endpoint. Here we present data detailing the VAT events in PIVOTAL, alongside univariate and multivariate analyses of risk association, testing the hypothesis that VAT may be independently associated with a proactive iron dosing regimen. Method In PIVOTAL 2141 adults with end-stage kidney disease within 12 months of initiating regular HD were randomised 1:1 to either high-dose intravenous iron administered proactively, or low-dose intravenous iron administered reactively, on the basis of monthly Ferritin and Transferrin saturation levels. Erythropoiesis Stimulating Agents were dosed sufficiently to maintain a haemoglobin of 100 to 120g/L. Vascular access use was recorded at baseline and on a monthly basis. VAT was regarded as a safety event with investigators mandated to record such events. VAT was defined clinically, with investigators expected to report thrombotic occlusion of the access (either arteriovenous or catheter thrombosis) significant enough to prevent further effective use without intervention. Baseline demographic, blood pressure and laboratory data underwent univariate analysis with regard to first event of VAT. Primary patient demographics (age, gender, primary renal disease, randomised treatment arm) were put forward for inclusion in a multivariable cox proportional hazards model alongside variables that associated on univariate testing with α&amp;lt;0.05. Analyses were performed using SAS software, version 9.4 (SAS Institute). Results 2141 eligible patients were randomised, of whom 877/2141 (41.0%) were using a central venous catheter (CVC), 1209/2141 (56.5%) an arteriovenous fistula (AVF), and 55/2141 (2.6%) an arteriovenous graft (AVG) at baseline. Over a median follow up of 2.1 years, 480/2141 (22.4%) experienced a VAT event; 194/887 (21.9%) of CVC patients; 263/1209 (21.8%) of AVF patients; and 23/55 (41.8%) of AVG patients. On univariate testing VAT events associated with diabetes as a cause of kidney failure (HR 1.44, 95%CI 1.19 to 1.74, p&amp;lt;0.001), AVG use at baseline (HR 2.37, p&amp;lt;0.001), digoxin use (HR 2.35, p=0.002), and diuretic use (HR 1.24, p=0.02). Angiotensin receptor blocker (ARB) use associated with less VAT (HR 0.66, p=0.013), as did male gender (HR 0.74, p=0.002), and never having smoked (HR 0.68, p=0.008). No association was seen with age, AVF use, CVC use, blood pressure, history of cardiovascular (CV) disease, atrial fibrillation, other CV medications, C-reactive protein, haemoglobin, transferrin saturation, ferritin or randomised treatment group (Proactive 262/1093 (24.0%) v Reactive 218/1048 (20.8%), HR 1.15, p=0.12) . Multivariate analysis found diabetes as a cause of kidney failure (HR 1.45, p&amp;lt;0.001), AVG use (HR 2.29, p&amp;lt;0.001), digoxin exposure (HR 2.48, p&amp;lt;0.001) and diuretic exposure (HR 1.25, p=0.018) to independently associate with VAT. Male gender (HR 0.75, p=0.002), never smoked (HR 0.68, p=0.004) and ARB use (HR 0.66, p=0.011) were found to independently associate with lower risk of VAT. Investigation of interaction between significant predictors found diuretic use in AVF patients to reach nominal significance (p=0.033). No other significant interactions being demonstrated. Conclusion In PIVOTAL, VAT affected nearly one quarter of the cohort over a median of 2.1 years. Diabetes as a cause of kidney failure, active smoking, AVG use, female gender, exposure to digoxin, and exposure to diuretic were independently associated with VAT, but this was not the case with higher iron dosing. ARB use was independently associated with lower risk.

P0691LIPOPROTEIN(A) AS A POTENTIAL RISK FACTOR FOR CARDIOVASCULAR (CV) AND THROMBOTIC EVENTS IN CHRONIC KIDNEY DISEASE (CKD) AND TRANSPLANTED PATIENTS

Abstract Background and Aims Several studies suggested an independent association between elevated Lipoprotein (a) [Lp(a)] levels and the incidence of CV events in the normal population. Lp(a) levels start to rise with decreasing glomerular filtration rate. Whether high Lp(a) serum levels may contribute to the pathogenesis of atherosclerosis or thrombosis in CKD and, particularly, in transplanted (Tx) patients is largely unclear. Furthermore, it is still uncertain to which extent very high Lp(a) levels might influence CV events in this population. Aims: 1. To evaluate Lp(a) serum concentrations and lipid profile in CKD, dialysis and Tx patients. 2. To investigate the relationship between Lp(a) serum levels and atherosclerotic cardiovascular disease (ASCVD), including myocardial infarction, coronary revascularization, cerebrovascular accident, carotid endarterectomy, peripheral revascularization, gangrene, or limb amputation. 3. To assess whether Lp(a) may have a role in thrombotic events (failure of vascular access in HD or early renal allograft thrombosis after transplantation) in these patients. Method Serum Lp(a) levels and lipid profile were assessed in 295 patients (M 172, F 123; mean age 57.3, range 19-85 years): 23 with CKD stage I-III, 76 with CKD stage IV-V, 128 on dialysis (68 hemodialysis (HD), 60 peritoneal dialysis) and 68 were kidney Tx recipients (eGFR&amp;gt;30 ml/min). In the latter group, Lp(a) values were assayed before and after transplantation. Lp(a) levels were determined using the Macra® Lp(a) ELISA kit (Trinity Biotech, USA). Values are expressed as median and interquartile range. Logistic regression analysis was used to determine whether Lp(a) is a risk factor for CV and thrombosis disease. The cut-off value was identified according to maximum Youden index by receiver operating characteristic (ROC) curve. Results Increased mean serum levels of LDL-C (93.85 mg/d; normal values=&amp;lt;70 mg/dl) were observed in all groups of patients, while HDL-C and triglycerides serum levels were in the normal range. Serum Lp(a) levels (nv=14-31 mg/dl) were significantly (p&amp;lt;0.001) increased in advanced CKD group (stage IV-V) (45.5, 1.5-216.5 mg/dl) and, mostly, in patients on dialysis treatment (63.2, 2.0-216.6 mg/dl, p=0.001) compared to mild-moderate CKD group (stage I-III) (32, 1.3-149 mg/dl). Lp(a) serum levels correlated significantly with age (r=0.11, p&amp;lt;0.05) and, inversely, with eGFR only in advanced CKD group (r=-0.21 p&amp;lt;0.05). A significant (-56%; p&amp;lt;0.001) decrease of serum Lp(a) was observed after renal Tx, while staying in HD for another year resulted in an increase in serum Lp (a) levels of about 23.7% (p&amp;lt;0.003). No significant relationship was found between Lp(a) values and gender, inflammation (as assessed by serum C-reactive protein levels), or diabetes. By logistic regression analysis, Lp(a) values were found to be a risk factors for ASCVD in the whole population (No events 246 pts: Lp(a) 47.8 mg/dl; Yes events 49 pts: Lp(a) 53.8 mg/dl; p=0.049) and for thrombotic events in HD group (vascular access thrombosis: 4 events) and Tx patients (early acute renal vein thrombosis after Tx: 4 events) (p=0.028). The ROC curve (AUC 0.7829, 95% CI 0.5751-0.9907) allowed us to define the cut-off value for serum Lp(a) (82.45 mg/dl) (sensitivity of 87%; specificity of 73%) as a thrombotic risk factor in HD and Tx patients. Conclusion The study confirms the relevance of Lp(a) as non-traditional CV risk factor in CKD and Tx patients predicting both, the development of ASCVD and thrombosis. Serum Lp(a) levels higher than 82.45 mg/dl are potential thrombotic risk factors for vascular access failure in HD patients or early acute renal allograft thrombosis in Tx patients, suggesting more aggressive strategies to lower Lp(a) serum levels in this patient setting.

Delivering Safe and Effective Hemodialysis in Patients with Suspected or Confirmed COVID-19 Infection: A Single-Center Perspective from Italy.

New “Severe Acute Respiratory Syndrome Coronavirus 2” (SARS-CoV-2) is responsible for a clinical entity named Coronavirus Disease 2109 (COVID-19) by the World Health Orgazination, which is now a pandemic (1). In Europe, Italy was the first, and so far the largest, epicenter of the epidemic. It is now clear that many asymptomatic and paucisymptomatic patients went undetected, causing significant diffusion of the disease. Asymptomatic infections are common: among 634 confirmed patients on board the “Diamond Princess” cruise ship, 306 were symptomatic and 328 asymptomatic at the time of testing (2). It is now clear that when a patient with atypical severe pneumonia was diagnosed as COVID-19 in a small city, Codogno, in a previously healthy 38-year-old man, on February 20, 2020, more patients with undetected COVID-19 were present in Northern Italy. In addition to the cluster around Codogno, about 50 km south of Milan, which was promptly put under strict lockdown, two additional relevant clusters emerged near the cities of Bergamo and Brescia. The delay in enforcing a lockdown in the latter areas is probably one of the leading causes of the more severe outbreak now affecting these provinces. Extensive testing in the initial phase of disease diffusion was adopted in the Italian Veneto area, resulting in better containment of new cases. A nationwide lockdown measure was passed by the Italian government when Northern Italy, which has the highest concentration of well organized hospitals in the country, started showing signs of difficulty handling the rapid increase of patients in need of treatment in intensive care units (ICUs). A comparison of Chinese and Italian data on COVID-19 may be of interest to other countries where the disease is now spreading. The Chinese Center for Disease Control and Prevention described the characteristics of a large cohort of COVID-19 patients (3), showing that …

Open and endovascular surgery for stenosis of the peripheral regions of arteriovenous fistula

Vascular access is the cornerstone of hemodialysis. With vascular access dysfunction, the results of treatment of patients with stage 5 chronic kidney disease significantly deteriorate. One of the most common causes of vascular access failure is peripheral venous stenosis. Despite the variety of initiating factors, the morphological substrate of stenotic damage to the arteriovenous fistula (or arteriovenous anastomosis) in most cases is neointimal hyperplasia. Stenotic lesions of the arterivenous fistula are strongly associated with an increased risk of thrombosis and loss of vascular access. There are 4 typical localizations of stenosis: arteriovenous or arteriograft anastomosis, stenosis of the juxta-anastomotic segment of the fistula, stenosis of the functional segment of the fistula, and stenosis of the cephalic arc.The most common indication for surgical treatment is vascular access failure; less common indications are clinical symptoms of venous insufficiency.There are various methods of open reconstruction of the stenotic segment of the fistula vein: resection, prosthetics with a synthetic vascular graft, prosthetics or plastic repair of the autologous vein wall, complete or partial drainage of the prestenotic segment of the vein, etc. Currently an alternative method of stenosis repair using endovascular interventions is gaining popularity. In contrast to central vein stenosis, where endovascular interventions are the gold standard, in peripheral vein stenosis it is only an adjuvant method. Complications of endovascular interventions are extremely rare.Despite the fact that endovascular interventions have almost absolute probability of technical success, the primary patency is not high and is about 50% in six months. The use of bare stents is not accompanied by an increase in primary patency. The use of stent-grafts can increase the primary patency, especially in the plastic repair of challenging stenoses of the graft-vein anastomosis or cephalic arch.Many issues related to endovascular interventions remain unresolved, which requires further research.

Thrombosis risks of permanent vascular access

Aim. To identify the factors affecting the occurrence of thrombosis of permanent vascular access and to determine their significance.&#x0D; Materials and Methods. The results of treatment of 168 patients with native arteriovenous radio-cephalic fistula were analyzed. The results of treatment were traced within 1 year. According to the results of treatment, patients were divided into 2 groups: the 1st group – patients who did not develop thrombosis of the arteriovenous fistula within 1 year of hemodialysis, and the 2nd group – patients with a dysfunction of permanent vascular access developed due to thrombosis within the first year.&#x0D; Results. On the basis of the obtained data, the risk factors for thrombosis of permanent vascular access within 6 months were: repeated operations, duration of anticoagulant therapy, correction of anticoagulant therapy, antibiotic therapy. Risk factors for thrombosis of the PVA for the period from 6 months to 12 months were: atherosclerosis, fistula vein diameter, repeated operations, the number of repeated operations, a reason for a repeated operation, duration of anticoagulant therapy, correction of anticoagulant therapy, antibiotic therapy.&#x0D; Conclusions. The results of the study suggest that the realization of the identified risk factors is not the only cause of complications. For a more detailed consideration of the probability for thrombosis of permanent vascular access in different time intervals, it seems appropriate to use multidimensional mathematical modeling.

Arteriovenous fistula thrombosis is associated with increased all-cause and cardiovascular mortality in haemodialysis patients from the AURORA trial.

BackgroundThe impact of arteriovenous fistula (AVF) or graft (AVG) thrombosis on mortality has been sparsely studied. This study investigated the association between AVF/AVG thrombosis and all-cause and cardiovascular mortality.MethodsThe data from 2439 patients with AVF or AVG undergoing maintenance haemodialysis (HD) included in the A Study to Evaluate the Use of Rosuvastatin in Subjects on Regular Hemodialysis: An Assessment of Survival and Cardiovascular Events trial (AURORA) were analysed using a time-dependent Cox model. The incidence of vascular access (VA) thrombosis was a pre-specified secondary outcome.ResultsDuring follow-up, 278 AVF and 94 AVG thromboses were documented. VA was restored at 22 ± 64 days after thrombosis (27 patients had no restoration with subsequent permanent central catheter). In multivariable survival analysis adjusted for potential confounders, the occurrence of AVF/AVG thrombosis was associated with increased early and late all-cause mortality, with a more pronounced association with early all-cause mortality {hazard ratio [HR] < 90 days 2.70 [95% confidence interval (CI) 1.83–3.97], P < 0.001; HR > 90 days 1.47 [1.20–1.80], P < 0.001}. In addition, the occurrence of AVF thrombosis was significantly associated with higher all-cause mortality, whether VA was restored within 7 days [HR 1.34 (95% CI 1.02–1.75), P = 0.036] or later than 7 days [HR 1.81 (95% CI 1.29–2.53), P = 0.001].ConclusionsAVF/AVG thrombosis should be considered as a major clinical event since it is strongly associated with increased mortality in patients on maintenance HD, especially in the first 90 days after the event and when access restoration occurs >7 days after thrombosis. Clinicians should pay particular attention to the timing of VA restoration and the management of these patients during this high-risk period. The potential benefit of targeting overall patient risk with more aggressive treatment after AVF/AVG restoration should be further explored.

Pentosidine in chronic hemodialysis patients: relation with arteriovenous fistula morphology and function.

It has been suggested that advanced glycation end products (AGEs) are involved in atherogenesis, vascular calcification and remodeling, including neointimal hyperplasia, in renal and non-renal patients. Their relevance for arteriovenous fistula (AVF) function has been poorly studied to date, with only one clinical study addressing the issue of thrombosis of vascular access in relation to AGEs in dialysis patients. We aimed to evaluate the relationship between serum pentosidine and AVF morphology and function. Eighty-eighth hemodialysis patients with patent native AVF were included. Ultrasound examination of AVF evaluated blood flow in the brachial artery, resistivity index (RI), the diameter of the vessels and the presence of stenosis. AVF and cardiovascular history were recorded, routine clinical and laboratory evaluation was performed and serum pentosidine was assessed. Forty-eight patients (54.54%) had AVF stenosis. Pentosidine correlated in univariate analysis with cholesterol (r = 0.270, p = 0.01), triglycerides (r = 0.309, p = 0.003), calcium (r = 0.040, p < 0.001) and inversely to dialysis vintage (r = - 0.453, p < 0.001), access vintage (r = - 0.432, p = 0.001), phosphate (r = - 0.211, p = 0.04), parathyroid hormone (r = - 0.211, p = 0.04), urea (r = - 0.230, p = 0.03), residual diameter of AVF (r = - 0.023, p = 0.03). In multivariate regression calcium (p = 0.006), access vintage (p = 0.03), and residual diameter of AVF vein (p = 0.02) remain significantly linked to pentosidine. Patients with pentosidine above median had higher cholesterol (179.91 vs. 160.97, p = 0.04), triglycerides (187.18 vs. 129.31, p = 0.002) and higher prevalence of hypertension (93.70% vs. 84.10%, p = 0.02). Our study suggests that pentosidine could be associated to vascular access morphology and function in dialysis patients.

Antiplatelet therapy for prevention of hemodialysis vascular access thrombosis and improving survival

Antiplatelet therapy for prevention of hemodialysis vascular access thrombosis and improving survival

Plasma levels of von Willebrand factor in maintenance hemodialysis patients: its relation to vascular access thrombosis

Objective The aim of this study was to assess von Willebrand factor (VWF) plasma levels in patients under maintenance hemodialysis (HD) to determine its role in the occurrence of vascular access thrombosis (VAT) in such patients. Background HD process is associated with increasing thrombotic trend especially owing to platelets and clotting factor activation. Vascular access complications increase morbidity and contribute to 20–25% of all hospitalizations in HD patients, of which ~ 85% of these cases are because of thrombosis. VWF is an important component of the hemostatic system and a hypercoagulability state biomarker. Patients and methods This case–control study was conducted on 60 patients on HD for more than 6 months classified into two groups: group I (GI) included 30 patients with VAT, whereas group II (GII) included 30 patients without VAT. Moreover, 20 healthy individuals served as a control group. History taking, clinical examination, and investigations (complete blood count, kidney function tests, liver function tests, lipid profile, fasting blood sugar, postprandial blood sugar, and serum VWF) for all cases were done. Results Mean VWF serum level was found to be higher in HD groups (GI 1361.47 ± 270.38 and GII 950 ± 138.12) than control group (351.5 ± 34.8), with highly statistical significance. A cutoff level of VWF at 1277 ng/ml is accurate (46.67%) for ocurrance of VAT in GI patients, with sensitivity of 93.33%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 93.8%. Conclusion High VWF levels related to development of VAT.

ADAMTS13 plasma level in maintenance hemodialysis patients: its relation to vascular access thrombosis

Objective The aim of this study was to evaluate ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) plasma level in patients under maintenance hemodialysis (HD) to determine its relation in the occurrence of vascular access thrombosis (VAT) in such patients. Background An increased thrombotic tendency is an important cause of complications in patients on chronic HD leading to thrombosis of the vascular access. VAT remains the main problem in vascular access for HD. Hypercoagulability in patients on chronic HD can be caused by a variety of factors, mainly consisting of platelet abnormalities and plasma factor abnormalities. Some of the plasma factor abnormalities are ADAMTS13 abnormalities. ADAMTS13 deficiency and/or the presence of antibodies against this enzyme may increase ultra large von Willebrand factor plasma levels, favoring the occurrence of thrombosis in small vessels. Materials and methods This case–control study was conducted on 60 patients on HD for more than 6 months classified into two groups: group I included 30 patients with VAT, and group II included 30 patients without VAT. Moreover, 20 healthy individuals served as a control group. History taking, clinical examination, and investigation were done. Results Mean ADAMTS13 serum level was found to be lower in HD groups of patients, with highly significant decrease in serum ADAMTS13 levels in group I (131.67 ng/ml) compared with group II (310.37 ng/ml) and group III (605.35 ng/ml), with P value of less than 0.001. A cut-off level at 200 ng/ml was accurate (95.00%) for occurrence of VAT in group I patients with sensitivity of 96.67%, specificity of 93.33%, positive predictive value of 93.55% and negative predictive value of 96.55%. Conclusion Low ADAMTS13 serum level was associated with occurrence of VAT.

Preventing arteriovenous shunt failure in hemodialysis patients: a population‐based cohort study

Essentials Uncertainty remains about antiplatelets for vascular access patency in hemodialysis patients. 95971 people under hemodialysis were followed in a claims database in Taiwan. Aspirin reduced vascular access failure rate and did not increase major bleeding rate. Clopidogrel, Aggrenox, and warfarin might increase major bleeding rate. SUMMARY: Background Dialysis adequacy is a major determinant of survival for patients with end-stage renal disease. Good vascular access is essential to achieve adequate dialysis. Objectives This study evaluated the impacts of different drugs on the vascular access failure rate of an arteriovenous fistula or an arteriovenous graft and the rate of major bleeding in hemodialysis patients. Patients and methods We studied patients with end-stage renal disease registered in the Taiwan National Health Insurance program from 1 January 1997 to 31 December 2012. A total of 95971 patients were enrolled in our study. Vascular access dysfunction was defined as the need for thrombectomy or percutaneous angioplasty. Major bleeding was defined as emergency department visits or hospitalization with a primary diagnosis of gastrointestinal bleeding or intracerebral hemorrhage. The adjusted odds ratios between person-quarters with or without antiplatelet or oral anticoagulant use were calculated using a generalized estimating equation. Results The odds ratio of vascular access failure was 0.21 (0.11-0.39) for aspirin, 0.76 (0.74-0.79) for clopidogrel, 0.67 (0.59-0.77) for dipyridamole, 0.67 (0.53-0.86) for Aggrenox and 0.96 (0.90-1.03) for warfarin. The highest odds ratio for intracerebral hemorrhage was 5.33 (1.25-22.72) in younger patients using Aggrenox. The highest odds ratio for gastrointestinal bleeding was 1.34 (1.10-1.64) for clopidogrel. Conclusion Antiplatelet agents, but not warfarin, might reduce the vascular access thrombosis rate. The gastrointestinal bleeding rate was increased in the group using clopidogrel. Aggrenox should be used with caution in young individuals because it might increase the rate of intracerebral hemorrhage.

Thrombophilia associated with early post-angioplasty thrombosis of dialysis vascular access

Retrospective single-center review between February and October 2015. There were 462 patients who underwent percutaneous transluminal angioplasty (PTA) for dialysis vascular access malfunction and were tested for protein C, protein S, antithrombin III, and anticardiolipin antibodies. The authors administered antiplatelet therapy for 3 days after PTA. Forty-one (9%) suffered occlusions of their access within 30 days of angioplasty. Overall, 26 (63%) patients in the early thrombosis group had at least one thrombophilic factor compared with 15 (37%) patients who did not clot their access until after 30 days (P = .03). Thrombophilia is associated with early occlusion after angioplasty for hemodialysis vascular access.