Consistent aspirin use associated with improved arteriovenous fistula survival among incident hemodialysis patients in the dialysis outcomes and practice patterns study

Continuous aspirin treatment improves cardiovascular events and all-cause mortality in hemodialysis patients with peripheral artery disease

BACKGROUND

Hemodialysis (HD) patients with peripheral arterial disease (PAD) are at heightened risk of adverse vascular events, and aspirin positively affects those outcomes. We aimed to investigate the association between different patterns of aspirin use and clinical vascular events in chronic HD patients with PAD.

METHODS

This retrospective nationwide cohort study enrolled 758 chronic HD patients who had been diagnosed with PAD between January 1, 2008, and December 31, 2012, and followed up until the end of 2020. Patients were divided into three groups according to medication possession ratio (MPR) and continued use of aspirin (i.e., low MPR, high MPR but discontinuous prescription, and high MPR and continuous prescription). Percutaneous transluminal angioplasty (PTA), surgical bypass, lower leg amputation, cardiovascular events, cerebrovascular events, and all-cause mortality were evaluated.

RESULTS

High MPR and continuous aspirin use had the lowest incidence of all-cause mortality and cardiovascular events compared with the two other groups, and it was significantly associated with low risk of PTA, surgical bypass, cardiovascular events, and all-cause mortality (aHR: 0.58 [0.41-0.83], 0.49 [0.25-0.95], 0.57 [0.40-0.81], and 0.70 [0.55-0.88], respectively). Kaplan-Meier analysis revealed that event-free rates of PTA, cardiovascular events, and all-cause mortality of patients with high MPR and continuous aspirin treatment were the highest among the three groups (p < 0.05).

CONCLUSION

Among HD patients with PAD, high MPR and continuous aspirin use significantly reduced the risk of PTA, surgical bypass, cardiovascular events, and all-cause mortality and improved the event-free rates of PTA, cardiovascular events, and all-cause mortality during long-term follow-up.

The Pathological Mechanisms and Therapeutic Molecular Targets in Arteriovenous Fistula Dysfunction

The number of patients with end-stage renal disease (ESRD) requiring hemodialysis is increasing worldwide. Although arteriovenous fistula (AVF) is the best and most important vascular access (VA) for hemodialysis, its primary maturation failure rate is as high as 60%, which seriously endangers the prognosis of hemodialysis patients. After AVF establishment, the venous outflow tract undergoes hemodynamic changes, which are translated into intracellular signaling pathway cascades, resulting in an outward and inward remodeling of the vessel wall. Outward remodeling refers to the thickening of the vessel wall and the dilation of the lumen to accommodate the high blood flow in the AVF, while inward remodeling is mainly characterized by intimal hyperplasia. More and more studies have shown that the two types of remodeling are closely related in the occurrence and development of, and jointly determining the final fate of, AVF. Therefore, it is essential to investigate the underlying mechanisms involved in outward and inward remodeling for identifying the key targets in alleviating AVF dysfunction. In this review, we summarize the current clinical diagnosis, monitoring, and treatment techniques for AVF dysfunction and discuss the possible pathological mechanisms related to improper outward and inward remodeling in AVF dysfunction, as well as summarize the similarities and differences between the two remodeling types in molecular mechanisms. Finally, the representative therapeutic targets of potential clinical values are summarized.

Effect of aspirin on cardiovascular events in patients undergoing hemodialysis with hyperphosphatemia: A post hoc analysis of the LANDMARK trial

INTRODUCTION

The clinical benefits of aspirin in patients undergoing hemodialysis remain unclear.

METHODS

The secondary analysis of the LANDMARK trial investigated whether aspirin use was associated with cardiovascular events (CVEs) and all-cause mortality was performed. A total of 2135 patients at risk for vascular calcification were analyzed using a Cox proportional hazards model with propensity score matching.

RESULTS

The risk of CVEs was comparable between participants with aspirin use at baseline and those without at baseline, between participants with aspirin use during the study period and those without during the study period, and between participants with new aspirin prescription and those without aspirin use during the study period.

CONCLUSION

Aspirin use was not significantly associated with a lower risk of CVEs in participants undergoing hemodialysis patients at risk of vascular calcification.

Low-Dose Aspirin Use Significantly Improves the Survival of Late-stage NPC: A Propensity Score-Matched Cohort Study in Taiwan

Background: Aspirin use has been associated with improved survival rates in various cancers. However, it remains unclear if aspirin confers a survival benefit on patients with nasopharyngeal carcinoma (NPC). The aim of this study was to assess the associations between aspirin use and survival in different stages of NPC. Methods: This is a 10-year retrospective cohort study of NPC patients. A total of 565 NPC patients were recruited after we performed a 1:4 propensity score match between aspirin users and non-users. Cox regression models with adjusted covariates were employed to evaluate factors that influence the survival rate of NPC patients. Results: The Kaplan-Meier analysis revealed that the overall survival (p < 0.0001) and disease-specific survival (p < 0.0001) rates of 180-day aspirin users increased. Increased survival rates were also observed in 180-day aspirin users with Stages III and IV, T, N1 and 2, and N3 categories. Cox regression models indicated that factors, including aspirin use (univariate: HR = 0.28, 95% CI = 0.14-0.55, p < 0.001; multivariate: HR = 0.23, 95% CI = 0.12-0.46, p < 0.001), were independent prognostic factors for survival. Conclusions: Aspirin use for more than 180 days is associated with an increased survival rate and is a positive independent prognostic factor in NPC.

Endovascular Arteriovenous Dialysis Fistula Intervention: Outcomes and Factors Contributing to Fistula Failure

RATIONALE & OBJECTIVE

Primary patency is variable with arteriovenous fistulas, and many patients require angiographic procedures to obtain patency. Accordingly, we determined postintervention patency rates and contributing factors for fistula failure following intervention to establish secondary patency in non-dialysis-dependent patients with advanced chronic kidney disease following creation of an arteriovenous fistula.

STUDY DESIGN

Observational study from a single referral center.

SETTING & PARTICIPANTS

210 non-dialysis-dependent patients with advanced chronic kidney disease who underwent upper-extremity fistula creation for anticipated dialysis between October 1995 and January 2015 and who required subsequent endovascular therapy to establish or maintain patency were reviewed.

EXPOSURE

Endovascular therapy for dialysis arteriovenous fistula primary patency failure.

OUTCOMES

Postintervention patency duration following endovascular therapy.

ANALYTICAL APPROACH

Descriptive study with outcomes determined using Cox proportional hazards models.

RESULTS

Multiple fistula configurations were reviewed: 138 (65.7%) brachiocephalic, 39 (18.6%) radiocephalic, 30 (14.3%) brachiobasilic, 2 (1.0%) ulnocephalic, and 1 (0.5%) radiobasilic. There were 261 initial stenoses treated. Postintervention primary patency is defined as the time from the index intervention to repeat intervention for stenosis. Postintervention primary-assisted patency is the time from the index intervention to thrombectomy for fistula thrombosis or change in modality. Postintervention secondary patency is the time from the index intervention to fistula abandonment. Median postintervention primary patency, postintervention primary-assisted patency, and secondary patency were 2.7, 3.2, and 3.6 years, respectively. The overall 1-year primary, primary-assisted, and secondary patency rates in this cohort were 53.0%, 87.7%, and 83.5%, respectively. Compared with radiocephalic fistulas, brachiocephalic fistulas had higher risk for postintervention primary patency loss (HR, 1.90; 95% CI, 1.13-3.20; P = 0.02).

LIMITATIONS

Dialysis fistula revascularization techniques varied.

CONCLUSIONS

The radiocephalic fistula configuration had the best postintervention primary patency in this cohort. Postintervention primary-assisted patency and secondary patency were not significantly different among different fistula configurations.

Effects of aspirin resistance and mean platelet volume on vascular access failure in hemodialysis patients

BACKGROUND/AIMS

Maintaining the patency of vascular access (VA) in hemodialysis (HD) patients is important and can be life-saving. We investigated the effects of aspirin resistance and mean platelet volume (MPV) on VA failure in HD patients.

METHODS

We enrolled 163 patients on maintenance HD. VA failure was defined as thrombosis or a decrease of > 50% of the normal vessel diameter, as revealed by angiography.

RESULTS

Aspirin resistance was observed in 17 of 109 patients in whom this parameter was measured, and was not significantly associated with VA failure (p = 0.051). The mean MPV was 9.15 ± 0.05 fL. The 163 patients were grouped by the median MPV value (9.08 fL) at baseline; patients with higher MPVs (n = 82) had lower platelet counts (p = 0.002) and albumin levels (p = 0.009). During 34 months of follow-up, 65 VA failures (39.9%) occurred. The Kaplan-Meier curve revealed significant differences between the two groups in terms of cumulative VA failure (54.1% vs. 35.3%, p = 0.018). On multivariate analysis, the MPV (hazard ratio [HR], 1.794; 95% confidence interval [CI], 1.066 to 3.020; p = 0.028), platelet count (HR, 1.003; 95% CI, 1.001 to 1.006; p = 0.01), and smoking status (HR, 1.894; 95% CI, 1.019 to 3.519; p = 0.043) independently predicted VA failure.

CONCLUSION

A high MPV was associated with an increased risk of VA failure, whereas aspirin resistance showed only a weak association. The MPV may predict VA survival in HD patients.

The Effect of Aspirin on Preventing Vascular Access Dysfunction in Incident Hemodialysis Patients: A Prospective Cohort Study in Korean Clinical Research Centers for End-Stage Renal Disease (CRC for ESRD)

Background: Aspirin is often prescribed empirically to improve the patency of hemodialysis (HD) vascular access. Therefore, this study aimed to investigate the impact of aspirin on the survival of vascular access in incident HD patients with arteriovenous fistula (AVF) or arteriovenous graft (AVG). Methods: A prospective cohort of 881 incident HD patients was enrolled between 2009 and 2014. The primary outcome was defined as the first AVF/AVG intervention or salvage procedure, including percutaneous transluminal angioplasty or surgery for vascular access failure. Cox analyses were performed to determine the association between aspirin usage and the occurrence of the primary outcome. Results: The mean age of the patient group was 57.9 ± 13.4, and 63.8% of the patients were male. Aspirin was prescribed in 241 (27.4%) patients, and the median follow-up duration was 30 months. During follow-up, 180 (20.4%) patients experienced the primary outcome event. Univariate analysis showed that age, gender, presence of diabetes mellitus (DM), preexisting peripheral arterial disease, and the type of vascular access used (AVG versus AVF) were significantly associated with the development of the primary outcome. However, aspirin usage from the baseline was not significantly associated with primary outcome events (hazard ratio (HR): 1.16; 95% confidence interval (CI): 0.84–1.60; p = 0.378). Multivariate analysis showed that gender, the presence of DM, and the type of vascular access were still significantly associated with the occurrence of the primary outcome. Moreover, we did not observe the protective effect of taking aspirin on primary vascular access failure, even in subgroup analyses stratified according to gender, the presence of DM, and the type of vascular access. Conclusion: Physicians should carefully consider when they prescribe aspirin for the prevention of primary vascular access failure in Korean incident HD patients. In addition, larger prospective interventional studies are needed to elucidate the effect of aspirin on vascular access failure.

Spanish Clinical Guidelines on Vascular Access for Haemodialysis

Vascular access for haemodialysis is key in renal patients both due to its associated morbidity and mortality and due to its impact on quality of life. The process, from the creation and maintenance of vascular access to the treatment of its complications, represents a challenge when it comes to decision-making, due to the complexity of the existing disease and the diversity of the specialities involved. With a view to finding a common approach, the Spanish Multidisciplinary Group on Vascular Access (GEMAV), which includes experts from the five scientific societies involved (nephrology [S.E.N.], vascular surgery [SEACV], vascular and interventional radiology [SERAM-SERVEI], infectious diseases [SEIMC] and nephrology nursing [SEDEN]), along with the methodological support of the Cochrane Center, has updated the Guidelines on Vascular Access for Haemodialysis, published in 2005. These guidelines maintain a similar structure, in that they review the evidence without compromising the educational aspects. However, on one hand, they provide an update to methodology development following the guidelines of the GRADE system in order to translate this systematic review of evidence into recommendations that facilitate decision-making in routine clinical practice, and, on the other hand, the guidelines establish quality indicators which make it possible to monitor the quality of healthcare.

Association between post-dialysis hemoglobin level and the survival of vascular access

INTRODUCTION

Although a few dialysis facilities conduct a complete blood cell count for some patients at post-dialysis, including hemoglobin, clinical findings supporting the interpretation of results are scarce. The aim of this study was to investigate the association between post-dialysis hemoglobin level and vascular access failure with clinical data.

METHODS

Study design: Case crossover design.

SETTING

Japanese dialysis facilities, which routinely take post-dialysis blood samples, including complete blood cell counts at least once a month.

PARTICIPANTS

Hemodialysis patients who experienced vascular access failure in January 2010 until December 2014.

EXPOSURE

Post-dialysis hemoglobin level.

MAIN OUTCOME

Vascular access failure treated with endovascular treatment or operation.

STATISTICAL ANALYSIS

Self-matched odds ratios and 95% confidence intervals were estimated by comparing post-dialysis hemoglobin just before events ("case") with levels at 6 and 12 months before events ("control") using conditional logistic regression, and presented with restricted cubic spline.

RESULTS

Two hundred and thirty hemodialysis patients with vascular access failure were identified. Mean post-dialysis hemoglobin level before the failure was 11.8 g/dL (standard deviation 1.7). The spline curve showed that higher post-dialysis hemoglobin levels above 11.8 g/dL had a greater odds ratio for vascular access failure. Post-dialysis hemoglobin levels and odds ratios (95% confidence interval) for vascular access failure relative to the reference value (Hb 11.8 g/dL) were Hb 12.0 g/dL, 1.1 (1.0-1.1); Hb 14.0 g/dL, 1.4 (1.0-2.0); and Hb 16.0 g/dL, 2.1 (1.1-4.3).

CONCLUSIONS

A higher post-dialysis hemoglobin level was associated with vascular access failure. Higher post-dialysis Hb could be a factor that triggers vascular access failure.

Baseline characteristics of the omega-3 fatty acids (Fish oils) and Aspirin in Vascular access OUtcomes in REnal Disease (FAVOURED) study

AIM

The Fish oils and Aspirin in Vascular access OUtcomes in REnal Disease (FAVOURED) trial investigated whether 3 months of omega-3 polyunsaturated fatty acids, either alone or in combination with aspirin, will effectively reduce primary access failure of de novo arteriovenous fistulae. This report presents the baseline characteristics of all study participants, examines whether study protocol amendments successfully increased recruitment of a broader and more representative haemodialysis cohort, including patients already receiving aspirin, and contrasts Malaysian participants with those from Australia, New Zealand and the United Kingdom (UK).

METHOD

This international, randomized, double-blind, placebo-controlled trial included patients older than 19 years with stage 4 or 5 chronic kidney disease currently receiving, or planned within 12 months to receive haemodialysis.

RESULTS

Participants (n = 568) were overweight (28.6 ± 7.3 kg/m(2) ), relatively young (54.8 ± 14.3 years), and predominantly male (63%) with a high prevalence of diabetes mellitus (46%) but low rate of ischaemic heart disease (8%). Sixty one percent were planned for lower arm arteriovenous fistula creation. Malaysian participants (n = 156) were younger (51.8 ± 13.6 years vs 57.1 ± 14.2 years, P < 0.001) with a higher prevalence of diabetes mellitus (65% vs 43%, P < 0.001), but less ischaemic heart disease (5% vs 14%, P < 0.01) compared with the combined Australian, New Zealand and UK cohort (n = 228). Protocol modifications allowing for inclusion of patients receiving aspirin increased the prevalence of co-morbidities compared with the original cohort.

CONCLUSIONS

The FAVOURED study participants, while mostly similar to patients in contemporary national registry reports and comparable recent clinical trials, were on average younger and had less ischaemic heart disease. These differences were reduced as a consequence of including patients already receiving aspirin.

Should patients be on antithrombotic medication for their first arteriovenous fistulae?

PURPOSE

Evidence on the effect of antithrombotic medication on reducing early and late fistula failure is inconclusive. Antithrombotic use carries risks in patients with end-stage renal failure and could increase the risk of needling complications as a result of bleeding. The objectives of this study are to determine the effect of antithrombotic agents on early and late fistula failure and on the risk of interrupted start of cannulation of the fistula.

METHODS

Retrospective analysis of two prospectively maintained databases of access operations and dialysis sessions of 671 patients who had their first fistula between 2004 and 2011. Early failure was defined as failure to reach six consecutive dialysis sessions at any time with two needles on the index form of access. Fistula survival was defined as the time from when the fistula was first used to fistula abandonment.

RESULTS

Primary failure was similar between patients on antiplatelet (18.8%), anticoagulants (18.4%) or no antithrombotic medication (18.8%; p = 0.998). Antithrombotic medication did not have an effect on AVF survival (p = 0.86). Antithrombotic medication did not increase complicated cannulation rates, defined as the percentage of patients failing to achieve six uninterrupted dialysis sessions from the start (p = 0.929).

CONCLUSIONS

Antithrombotic medication had no significant effect on primary failure rate, long-term fistula survival or initial complicated cannulation rates in our study. This suggests that patients already on antithrombotic medication can continue taking them without increasing the risk of interrupted dialysis.

Effects of Tongmai oral liquid in femoral ateriovenous fistula

BACKGROUND

This study was conducted to investigate the protective effect of Tongmai oral liquid on arteriovenous fistula function and to provide an effective method to promote fistula maturation.

METHODS

Fifteen female and fifteen male SPF New Zealand rabbits were randomly allocated into 3 groups including control, Aspirin and Tongmai oral liquid groups. A side-to-side femoral arteriovenous fistula was established in each rabbit and then animals were treated with Aspirin or Tongmai oral liquid for 2 weeks. The concentrations of circulating ET-1 and NO were determined before and after operation (on preoperative day, operative day, post-D1, post-D3, post-D7 and post-D15), respectively. Blood flow of the fistula stoma and contralateral artery and vein was determined on the 15th postoperative day. Last, the fistula stoma was dissected to observe patency, thrombosis and adhesion with surrounding tissues.

RESULTS

28 rabbits survived during the surgical process and the following 15-day observational period. Tissue adhesion of arteriovenous fistula with surrounding tissues was improved and fistula thrombosis was reduced by treatment with Tongmai oral liquid. NO concentration decreased to a different extent after vascular surgery. Tongmai oral liquid failed to regulate the equilibrium between NO and ET-1, but it improved blood flow of fistula stoma, as compared to control and Aspirin groups. Blood flow of fistula stoma in the three groups was lower than that of the contralateral femoral artery.

CONCLUSIONS

Tongmai oral liquid improved the function of femoral ateriovenous fistula in the rabbit model by increasing blood flow and reducing thrombosis, probably not by regulating the dynamic equilibrium between NO and ET-1.

The Omega-3 fatty acids (Fish Oils) and Aspirin in Vascular access OUtcomes in REnal Disease (FAVOURED) study: the updated final trial protocol and rationale of post-initiation trial modifications

Background

The FAVOURED study is an international multicentre, double-blind, placebo-controlled trial which commenced recruitment in 2008 and examines whether omega-3 polyunsaturated fatty acids (omega-3 PUFAs) either alone or in combination with aspirin will effectively reduce primary access failure of de novo arteriovenous fistulae (AVF) in patients with stage 4 and 5 chronic kidney disease. Publication of new evidence derived from additional studies of clopidogrel and a high screen failure rate due to prevalent aspirin usage prompted an updated trial design.

Methods/design

The original trial protocol published in 2009 has undergone two major amendments, which were implemented in 2011. Firstly, the primary outcome ‘early thrombosis’ at 3 months following AVF creation was broadened to a more clinically relevant outcome of ‘AVF access failure’; a composite of thrombosis, AVF abandonment and cannulation failure at 12 months. Secondly, participants unable to cease using aspirin were allowed to be enrolled and randomised to omega-3 PUFAs or placebo. The revised primary aim of the FAVOURED study is to test the hypothesis that omega-3 PUFAs will reduce rates of AVF access failure within 12 months following AVF surgery. The secondary aims are to examine the effect of omega-3 PUFAs and aspirin on the individual components of the primary end-point, to examine the safety of study interventions and assess central venous catheter requirement as a result of access failure.

Discussion

This multicentre international clinical trial was amended to address the clinically relevant question of whether the usability of de novo AVF at 12 months can be improved by the early use of omega-3 PUFAs and to a lesser extent aspirin. This study protocol amendment was made in response to a large trial demonstrating that clopidogrel is effective in safely preventing primary AVF thrombosis, but ineffective at increasing functional patency. Secondly, including patients taking aspirin will enrol a more representative cohort of haemodialysis patients, who are significantly older with a higher prevalence of cardiovascular disease and diabetes which may increase event rates and the power of the study.

Trial registration

Australia & New Zealand Clinical Trial Register (ACTRN12607000569404)

Preserving arteriovenous fistula outcomes during surgical training

PURPOSE

Arteriovenous fistulae (AVFs) are the preferred option for vascular access, as they are associated with lower mortality in hemodialysis patients than in those patients with arteriovenous grafts (AVGs) or central venous catheters (CVCs). We sought to assess whether vascular access outcomes for surgical trainees are comparable to fully trained surgeons.

METHODS

A prospectively collected database of patients was created and information recorded regarding patient demographics, past medical history, preoperative investigations, grade of operating surgeon, type of AVF formed, primary AVF function, cumulative AVF survival and functional patency.

RESULTS

One hundred and sixty-two patients were identified as having had vascular access procedures during the 6 month study period and 143 were included in the final analysis. Secondary AVF patency was established in 123 (86%) of these AVFs and 89 (62.2%) were used for dialysis. There was no significant difference in survival of AVFs according to training status of surgeon (log rank x2 0.506 p=0.477) or type of AVF (log rank x2 0.341 p=0.559). Patency rates of successful AVFs at 1 and 2 years were 60.9% and 47.9%, respectively.

CONCLUSION

We have demonstrated in this prospective study that there are no significant differences in outcomes of primary AVFs formed by fully trained surgeons versus surgical trainees. Creation of a primary AVF represents an excellent training platform for intermediate stage surgeons across general and vascular surgical specialties.

Vascular access care and treatment practices associated with outcomes of arteriovenous fistula: international comparisons from the Dialysis Outcomes and Practice Patterns Study

BACKGROUND

Vascular access (VA) guidelines recommend the native arteriovenous fistula (AVF) as VA of first choice for chronic hemodialysis patients. AVF management is important in hemodialysis patient care. AVF survival is associated with various physical factors, but the effects of dialysis treatment factors upon AVF survival are still not clear.

METHODS

Study patients were treated at 498 dialysis facilities participating in the Dialysis Outcomes and Practice Patterns Study (DOPPS) 2 or 3 (2002-2007). Analyses included 1,183 incident hemodialysis patients (on dialysis ≤7 days and using an AVF at study entry) and 949 prevalent patients (on dialysis >7 days at DOPPS entry and using a new AVF created during study observation). AVF survival was modeled from the study entry date for incident patients and date of first AVF use for prevalent patients. Predictors of primary and final AVF survival were compared across Japan, North America and Europe/Australia/New Zealand (EUR/ANZ) with adjustments for patient characteristics.

RESULTS

No meaningful relationship was seen between AVF survival and various physician and staff practices. However, patients with prior catheter use displayed higher rates of primary and final AVF failure. Final AVF failure rates were higher in facilities with higher median blood flow rates (BFR). They were also greater in North America and EUR/ANZ than in Japan, but this difference was substantially attenuated after accounting for regional differences in facility median BFR.

CONCLUSION

AVF longevity differed according to the DOPPS region, and was related to prior patient catheter use and facility BFR practice. Further longitudinal studies may help demonstrate meaningful associations between VA-handling skill and patency.

Thrombophilia and arteriovenous fistula survival in ESRD

BACKGROUND AND OBJECTIVES

The role of thrombophilia in failing arteriovenous fistula (AVF) among patients with ESRD undergoing hemodialysis is not established. This study aimed to assess whether AVF primary patency is associated with thrombophilia and coagulation abnormalities.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This observational study screened 219 patients between 2002 and 2004 for thrombophilia before AVF surgery. Thrombophilia included factor V Leiden and prothrombin G20210A mutations, protein C and antithrombin activities, and protein S. Coagulation abnormalities included high factor VIII:C, homocysteine, fibrinogen, and d-dimer levels; presence of antiphospholipid antibodies; and short thrombin time. We reviewed patient charts for comorbid conditions, AVF maturation and interventions, kidney transplantation, and patient survival (mean follow-up duration, 3.6 [range, 2.3-5.8] years). Primary patency from the AVF placement and functional primary patency from the first AVF cannulation were analyzed with Kaplan-Meier and Cox proportional hazards models.

RESULTS

Thrombophilia was present in 9% of the patients, and coagulation abnormalities occurred in 77%. One-year primary patency was 68%; 46% of the AVF failures occurred before the initiation of hemodialysis. Female sex (hazard ratio [HR], 2.6; 95% confidence interval [CI], 1.7-4.1) and thrombophilia (HR, 2.2; 95% CI, 1.2-4.2) were independent risk factors for loss of primary patency. Thrombophilia mutations or low antithrombin level (HR, 3.8), female sex (HR, 2.5), and diabetes (HR, 1.9) were associated with shortened functional primary patency of AVF.

CONCLUSIONS

Against the background of frequent coagulation abnormalities, thrombophilia and female sex predispose patients with ESRD to access failure, mostly due to thrombosis or stenosis.

Association of maturation period blood pressure with dialysis access patency

Problematic dialysis vascular access is a major health issue. The purpose of this study was to evaluate for potentially modifiable factors associated with access patency, particularly, the association of early postoperative, or maturation period, blood pressure with patency. A retrospective review was performed of patients who had undergone placement of an arteriovenous fistula or graft. Demographic, operative, and postoperative factors were evaluated for possible association with access primary patency using univariate and multivariate Cox regression analyses. Seventy-three patients over a 3-year review period were examined. Overall analysis showed a significant association of absence of peripheral vascular disease, aspirin use, and absence of previous permanent dialysis access with higher primary patency rates. Fistula subgroup analysis showed that higher blood pressure during the maturation period relative to preoperative blood pressure was associated with lower patency rates. For grafts, race was significantly associated with patency, with blacks having higher patency rates than whites. Multiple clinical factors were found to have a significant association with dialysis access primary patency. The finding of an association of maturation period blood pressure with fistula patency suggests that the maturation period environment, specifically hemodynamics during this time, may play an important role in dialysis access patency.

Aspirin is beneficial in hypertensive patients with chronic kidney disease: a post-hoc subgroup analysis of a randomized controlled trial

OBJECTIVES

The purpose of this study was to determine the benefit and risk associated with antiplatelet therapy in the chronic kidney disease (CKD) population.

BACKGROUND

Cardiovascular and possibly bleeding risks are elevated in patients with CKD. The balance of benefit and harm associated with antiplatelet therapy remains uncertain.

METHODS

The HOT (Hypertension Optimal Treatment) study randomly assigned participants with diastolic hypertension to aspirin (75 mg) or placebo. Study treatment effects were calculated using univariate proportional hazards regression models stratified by baseline estimated glomerular filtration rate (eGFR) with trends tested by adding interaction terms. End points included major cardiovascular events, total mortality, and major bleeding.

RESULTS

The study included 18,597 participants treated for 3.8 years. Baseline eGFR was < 60 ml/min/1.73 m(2) in 3,619 participants. Major cardiovascular events were reduced by 9% (95% confidence interval [CI]: -9% to 24%), 15% (95% CI: -17% to 39%), and 66% (95% CI: 33% to 83%) for patients with baseline eGFR of ≥ 60, 45 to 59, and < 45 ml/min/1.73 m(2), respectively (p trend = 0.03). Total mortality was reduced by 0% (95% CI: -20% to 17%), 11% (95% CI: -31% to 40%), and 49% (95% CI: 6% to 73%), respectively (p trend = 0.04). Major bleeding events were nonsignificantly greater with lower eGFR (hazard ratio [HR]: 1.52 [95% CI: 1.11 to 2.08], HR: 1.70 [95% CI: 0.74 to 3.88], and HR: 2.81 [95% CI: 0.92 to 8.84], respectively; p trend = 0.30). Among every 1,000 persons with eGFR < 45 ml/min/1.73 m(2) treated for 3.8 years, 76 major cardiovascular events and 54 all-cause deaths will be prevented while 27 excess major bleeds will occur.

CONCLUSIONS

Aspirin therapy produces greater absolute reduction in major cardiovascular events and mortality in hypertensive patients with CKD than with normal kidney function. An increased risk of major bleeding appears to be outweighed by the substantial benefits.

The Effect of Antiplatelet Drugs on the Patency Rate of Arterio-venous Fistulae in Hemodialysis Patients

Although arterialovenous fistulae (AVF) is considered to be vital for chronic kidney disease (CKD) patients, but they may cause complications and problems. For instance they may fail soon after their creation. The most important cause of failure in these cases is intrafistula thrombus formation. Whereas anti-platelet drugs are not routinely used after fistulae creation, we conducted this study to determine the effect of these drugs (aspirin and dipyridamol) on the patency of AVFs. From Sep 2003 to Aug 2007, all CKD patients who needed AVF for hemodilysis were included in our study. After fistulae creation, they were randomly divided in 3 groups. The first group was received aspirin and the second one with dipyridamol and the third one was the control group that received placebo. Each group consisted of 130 patients. Exclusion criteria were bleeding tendency, active peptic ulcer disease, pregnancy, lactation, use of anticoagulant and or non steroidal anti-inflammatory drugs, hepatic insufficiency and history of significant side effects from aspirin or dipyridamol. The patency of AVF in the control, aspirin and dipyridamol groups were obtained 69.2%, 70.8% and 75.4% respectively. Although the patency in the aspirin and the dipyridamol group were 1.6% and 6.2% more than the control group, but there was no statistically significant difference between them and placebo (The p-value was 0.892 for the aspirin group and 0.332 for the dipyridamol group). Our study showed that neither the aspirin nor the dipyridamol can be effective on the patency of AVF after 72 h even within six months period.

Vascular access for dialysis: recent lessons and new insights

PURPOSE OF REVIEW

Vascular access complications are a major cause of excessive morbidity and mortality in the dialysis population. This review will focus on recent changes in vascular access practices and access management directly affecting patient outcomes.

RECENT FINDINGS

The proportion of patients dialyzing via arteriovenous fistulas continues to increase as a result of national initiatives. Maturation failure is now the main obstacle to successful use of fistulas. Arteriovenous grafts remain an important vascular access option for dialysis, and interventions to prevent progression of stenosis are being explored. Central venous catheter prevalence has increased and new interventions to address catheter-related complications such as thrombosis and infection are promising.

SUMMARY

Advances in understanding the factors related to fistula maturation failure will have a major beneficial effect on vascular access outcomes. New approaches to prevent graft and catheter-related complications should complement advances on fistula management. Optimal patient selection for specific access modalities and institution of timely access interventions tested in rigorous clinical trials should be the next step to improve access management.

Antiplatelet medications in hemodialysis patients: a systematic review of bleeding rates

BACKGROUND AND OBJECTIVES

Patients with end stage renal disease (ESRD) are often prescribed antiplatelet medications. However, these patients are also at increased risk of bleeding compared with the general population, and an aim was made to quantify this risk with antiplatelet agents.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A systematic review of the literature (Medline, EMBASE, Cochrane CENTRAL and Google Scholar databases) was done to determine the bleeding risk in ESRD patients prescribed antiplatelet therapy. The secondary outcome was the effect on access thrombosis. All case series, cohort studies and clinical trials were considered if they included ten or more ESRD patients, assessed bleeding risk with antiplatelet agents, and lasted for more than 3 mo.

RESULTS

Sixteen studies, including 40,676 patients, were identified that met predefined inclusion criteria. Due to study heterogeneity and weaknesses in methodology, bleeding rates were not pooled across studies. However, the bleeding risk appears to be increased for hemodialysis patients treated with combination antiplatelet therapy. The results are mixed for studies using a single antiplatelet agent. Antiplatelet agents appear to be effective in preventing shunt and central venous catheter thrombosis, but not for preventing thrombosis of arteriovenous grafts.

CONCLUSION

The risks and benefits of antiplatelet agents in ESRD patients remain poorly defined. Until a clinical trial addresses this in the dialysis population, individual risk stratification taking into account the increased risk of bleeding should be considered before initiating antiplatelet agents, especially in combination therapy.