A pharmacodynamic study of clopidogrel in chronic hemodialysis patients

Evaluating Effectiveness and Safety in Chronic Kidney Disease with Atrial Flutter Using an Anticoagulation Strategy

Background and objectives: Recent randomized trials of oral antithrombotic drugs with atrial flutter (AFL) excluded patients with renal impairment because of their increased risk of bleeding. To date, no relevant studies have assessed the effectiveness and safety of different antithrombotic drugs in chronic kidney disease (CKD) patients with AFL. This cohort study evaluated the effectiveness and safety of different antithrombotic drugs in CKD patients with AFL. This study also investigated the risk of cardiovascular events from antithrombotic drugs through different risk profiles of stroke stratified by the CHA₂DS₂-VASc score. Materials and Methods: This cohort study was performed in patients with AFL and CKD who were extracted from the National Health Insurance (NHI) Database in Taiwan. Oral antithrombotic therapy (oral anticoagulants (OAC) or antiplatelets (APT)) was administered to patients who had been diagnosed with AFL after being diagnosed with CKD between 2011 and 2015. Primary outcomes, including ischemic stroke, systemic embolism, and composite of stroke, and secondary outcomes, including major adverse cardiac events (MACEs), major bleeding, all-cause mortality, and cardiovascular-related death, were examined. Results: A total of 2468 patients were included in this study. The results showed no statistically significant differences in the risk of primary outcomes. For the secondary outcomes, there were also no statistically significant differences in the risk of MACEs and major bleeding. However, the pooled results indicated that the hazard ratio (HR) for all-cause mortality with OAC was 0.24 (95% confidence interval (CI) = 0.10–0.55) compared with combination therapy, and the HR for APT compared with OAC was 2.86 (95% CI = 1.48–5.53). Conclusions: In the studied population, OAC or APT alone were proved equally effective for stroke prophylaxis. Furthermore, OAC might reduce the all-cause mortality rate compared with APT and should be considered as the first choice of oral antithrombotic drugs in patients with AFL and CKD.

Role of antiplatelet therapy in the durability of hemodialysis access

BACKGROUND

Antiplatelet therapy (APT) is often used on anecdotal grounds to improve vascular access patency. The aim of this study was to assess the role of APT in hemodialysis (HD) patients undergoing arteriovenous fistula (AVF) or graft (AVG) placement.

METHODS

All patients in a large HD vascular qualitative initiative database (2011-2017) were included and divided into no antiplatelet therapy (no-APT) vs. any APT [aspirin (ASA) or P2Y12 inhibitors (PI)]. Multivariate [logistic (MLR) and Cox (MCR) regression] analyses were used as appropriate.

RESULTS

A total of 24,847 patients undergoing HD access creation were identified (78% AVF). APT was noted among 49 and 46% of AVG and AVF patients, respectively. In MLR analysis, patients on no-APT vs. APT had a 12-fold increased risk of in-hospital mortality (odds ratio (OR) 11.79, [95% confidence interval 5.30-26.26]) and the risk of developing steal syndrome was higher among patients discharged on APT (OR 1.81, [1.19-2.76]). In patients undergoing AVF, primary patency (PP) was similar between APT and no-APT. However, in patients undergoing AVG, PP rates at 12 months were significantly higher for APT: ASA (47 vs. 41%) and PI (51 vs. 41%) than for no-APT (p = 0.008). At MCR analysis, the loss of PP at 12 months was 13% lower in ASA users (hazard ratio (HR) 0.87, [0.77-0.97], p = 0.02) and 24% lower in PI users (HR 0.76, [0.57-0.99], p = 0.046) compared to no-APT.

CONCLUSION

In a large national database, we showed that antiplatelet therapy was associated with lower in-hospital mortality. Aspirin and P2Y12-inhibitor use among AVG patients demonstrated improved PP rates compared to no antiplatelet therapy. We recommend the use of antiplatelet therapy especially in patients on AVG.

Prosthetic Arteriovenous Grafts for Hemodialysis

Introduction

Prosthetic arteriovenous (AV) grafts are indicated in patients with failed AV fistula (AVF), exhausted superficial veins or unsuitable vessels. Increasing the proportion of prevalent hemodialysis (HD) patients using autogenous AVF should reduce the need for AV grafts and associated morbidity. This paper reviews the current role of prosthetic AV grafts in vascular access for HD.

Technical considerations

Prior to the insertion of a prosthetic AV graft, a comprehensive review of previous access procedures and full physical examination in addition to vessel mapping is required. Anastomotic technique should take into account the flow diffuser concept, graft geometry and an anastomotic angle of 15° in order to reduce the incidence of intimal hyperplasia.

Results

Many authors report 1 and 2-yr cumulative graft patency rates of 59–90% and 50–82%, respectively. The major drawbacks with synthetic grafts include: thrombosis, a five-fold increase in infection risk and steal syndrome. The choice between surgical and percutaneous methods of dealing with blocked AV grafts remains controversial, though percutaneous techniques are assuming an increasingly important role. Percutaneous strategies are successful in declotting access in 67–95% of cases. Stenting of stenotic lesions following thrombectomy improves secondary patency rates. Strategies for dealing with AV graft infection include antibiotic prophylaxis, partial, subtotal or total graft excision and the use of biological prosthesis.

Conclusions

Though more prone to complications than autogenous AVFs, AV grafts offer a short maturation period and are more amenable to thrombectomy by radiological or surgical means. Complex AV grafts may be appropriate in patients with exhausted access sites.

Dual Antiplatelet Therapy and Clinical Outcomes after Coronary Drug-Eluting Stent Implantation in Patients on Hemodialysis

BACKGROUND AND OBJECTIVES

We aimed to investigate the benefits and risks of dual antiplatelet therapy (DAPT) after coronary drug-eluting stent (DES) implantation in patients undergoing hemodialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A nested case-control analysis of patients on hemodialysis after receipt of DES and DAPT treatment was conducted using data from Taiwan's National Health Insurance Research Database for the period 2007-2011. Cases of myocardial infarction or death within 1 year after DES implantation were matched one-to-one with control patients. Odds ratios were calculated to compare DAPT continuation with discontinuation. Additionally, a propensity score-adjusted 6-month landmark cohort analysis was also conducted to evaluate the long-term benefits and risks of prolonged (>6 months) compared with ≤6 months of DAPT use. The primary outcomes were death and myocardial infarction. The secondary outcomes were ischemic stroke, revascularization, and major bleeding.

RESULTS

In the nested case-control analysis, patients who continued DAPT had a lower rate of death or myocardial infarction within 1 year after receipt of a DES (adjusted odds ratio, 0.54; 95% confidence interval, 0.36 to 0.81; P=0.003), whereas this association became statistically nonsignificant when compared with patients who discontinued DAPT for the period between 6 and 12 months after receipt of a DES (adjusted odds ratio, 1.51; 95% confidence interval, 0.75 to 3.04). In the propensity score-adjusted cohort analysis, >6 months of DAPT use was not associated with different primary or secondary outcomes than shorter-term use.

CONCLUSIONS

Our findings support that the clinical effectiveness of extended DAPT in a hemodialysis population may be tempered after 6 months post-DES implantation.

Effectiveness and Safety of Antiplatelet in Stroke Patients with End-Stage Renal Disease Undergoing Dialysis

Background

Antiplatelet therapy is known to decrease the risk of secondary ischemic stroke. However, the effectiveness and safety of antiplatelet therapy in patients with end-stage renal disease are uncertain, especially in dialysis.

Aims and/or hypothesis

We estimated the effectiveness and safety of antiplatelet drugs (aspirin and clopidogrel) for the prevention of recurrent ischemic stroke in end-stage renal disease patients undergoing dialysis during long-term follow-up after first-time ischemic stroke.

Methods

The cases were identified from the National Health Insurance Research Database. Antiplatelet therapy was administered for 11 years to patients experiencing a first ischemic stroke between 1998 and 2006. Primary outcomes, including death and readmission to hospital for stroke, and secondary outcomes, including death, stroke, and acute myocardial infarction or bleeding, were examined.

Results

In total, 1936 patients experienced a first ischemic stroke during the follow-up. In a time-dependent analysis, the hazard ratio for primary outcomes in patients treated with aspirin was 0·671 ( P < 0·001) and that for clopidogrel was 0·933 ( P = 0·497). At secondary outcomes, patients treated with aspirin, hazard ratio for readmission for stroke was 0·715 ( P = 0·002) and that for bleeding was 0·885 ( P = 0·291). Independent risk factors for mortality and readmission due to ischemic stroke included age, diabetes mellitus, and administration of proton pump inhibitors.

Conclusions

Antiplatelet therapy, especially aspirin, still offers safe and effective treatment for ischemic stroke prevention in patients with end-stage renal disease undergoing dialysis.

The impact of chronic kidney disease on lipid management and goal attainment in patients with atherosclerosis diseases in Taiwan

BACKGROUND

Patients with chronic kidney disease (CKD) is a very high risk cardiovascular disease population and should be treated aggressively. We investigated lipid management in CKD patients with atherosclerosis in Taiwan.

METHODS

3057 patients were enrolled in a multi-center study (T-SPARCLE). Lipid goal are defined as total cholesterol (TC) < 160mg/dl, low-density lipoprotein (LDL) <100 mg/dl, high-density lipoprotein (HDL) > 40 mg/dl in men, HDL > 50 mg/dl in women, non-HDL cholesterol < 130mg/dl, and triglyceride < 150 mg/dl.

RESULTS

Compared with those without CKD (n=2239), patients with CKD (n=818) had more co-morbidities (hypertension, glucose intolerance, stroke and heart failure) and lower HDL but higher triglyceride levels. Overall 2168 (70.5%) patients received lipid-lowering agents. There was similar equivalent statin potency between CKD and non-CKD groups. The goal attainment is lower in HDL and TG in the CKD group as compared with non-CKD subjects (47.1 vs. 51.9% and 63.2 vs. 68.9% respectively, both p < 0.02). Analysis of sex and CKD interaction on goals attainment showed female CKD subjects had lower non-HDL and TG goals attainment compared with non-CKD males (both p < 0.019).

CONCLUSION

Although presenting with more comorbidities, the CKD population had suboptimal lipid goal attainment rate as compared with the non-CKD population. Further efforts may be required for better lipid control especially on the female CKD subjects.

Antiplatelet effects of prasugrel vs. double clopidogrel in patients on hemodialysis and with high on-treatment platelet reactivity

BACKGROUND

High on-treatment platelet reactivity (HTPR) is frequent in patients on hemodialysis (HD) receiving clopidrogel.

OBJECTIVES

The primary aim of this study was to determine the antiplatelet effects of prasugrel vs. high-dose clopidogrel in patients on HD with HTPR.

PATIENTS/METHODS

We performed a prospective, single-center, single-blind, investigator-initiated, randomized, crossover study to compare platelet inhibition by prasugrel 10 mg day(-1) with that by high-dose 150 mg day(-1) clopidogrel in 21 patients on chronic HD with HTPR. Platelet function was assessed with the VerifyNow assay, and genotyping was performed for CYP2C19*2 carriage.

RESULTS

The primary endpoint of platelet reactivity (PR, measured in P2Y12 reaction units [PRU]) was lower in patients receiving prasugrel (least squares [LS] estimate 156.6, 95% confidence interval [CI] 132.2-181.1) than in those receiving high-dose clopidogrel (LS 279.9, 95% CI 255.4-304.3), P < 0.001). The LS mean differences between the two treatments were - 113.4 PRU (95% CI - 152.9 to - 73.8, P < 0.001) and - 163.8 PRU (95% CI - 218.1 to - 109.2, P < 0.001) in non-carriers and carriers of at least one CYP2C19*2 allele, respectively. HTPR rates were lower for prasugrel than clopidogrel, in all patients (19% vs. 85.7%, P < 0.001) and in non-carriers (25.7% vs. 80%, P = 0.003). All carriers continued to show HTPR while receiving high-dose clopidogrel, but none showed it while receiving prasugrel.

CONCLUSIONS

In HD patients exhibiting HTPR following standard clopidogrel treatment, prasugrel 10 mg day(-1) is significantly more efficient than doubling the clopidogrel dosage in achieving adequate platelet inhibition. Neither effect seems to be influenced by carriage of the loss-of-function CYP2C19*2 allele.

Low responsiveness to thienopyridine in hemodialysis patients

We sought to evaluate whether thienopyridine low responsiveness, a predictor of stent thrombosis, is found in hemodialysis patients. We measured platelet aggregation at the site of implantation of drug-eluting stents in 333 patients with angina pectoris undergoing dual anti-platelet therapy. Thirty-one patients were on hemodialysis (HD group), and 302 were not (N-HD group). We used a novel whole-blood aggregometer. The aggregometer used the screen filtration method, with adenosine diphosphate as an agonist. The concentration of agonist required to induce 50% of the maximum pressure rate was calculated and indicated as the platelet aggregatory threshold index (PATI). Low responsiveness for thienopyridine was defined if the PATI levels were <4 μmol/l. PATI levels (μmol/l) were significantly lower in the HD group than in the N-HD group (6.8 ± 4.8 vs. 9.1 ± 5.4, P = 0.023), and the rate of low responsiveness for thienopyridine was significantly higher in the HD group than in the N-HD group (45.7 vs. 26.8%, P = 0.019). Non-fatal myocardial infarction and stent thrombosis occurred in three of the HD group and in nine of the N-HD group (P = 0.122). Late stent thrombosis occurred at a significantly higher rate in the HD group than in the N-HD group (P = 0.002). The rate of target lesion revascularization was significantly higher in the HD group than in the N-HD group (38 vs. 11.8%, P = 0.0001). In conclusion, low responsiveness to thienopyridine, as an indicator of platelet reactivity, is found more frequently in hemodialysis patients.

Coronary stent thrombosis in patients with chronic renal insufficiency

Renal insufficiency (RI) is a strong predictor of unfavorable outcomes after percutaneous coronary intervention (PCI). After PCI, stent thrombosis (ST) is a considerable concern. The risk of ST in RI has not been independently evaluated before. The mechanism of ST is frequently related to dual antiplatelet underuse. We reviewed the publications listed on Medline, Scopus, and EBSCO Host research database in the last two decades to identify the risk of ST in patients with RI. There are no enough data on the incidence of ST in RI patients. Platelet reactivity, appropriate period of dual antiplatelet therapy, coronary anatomy, selection of stent, and patient compliance are vital issues that warrant detailed evaluation in RI patients. Moreover, prospective trials and new therapeutic strategies are needed for proper assessment and management of ST in high-risk patients.

Risks and benefits of antiplatelet therapy in uremic patients

Patients with renal insufficiency are at an increased risk for cardiovascular morbidity and mortality. Despite being at a substantial risk for thrombotic events, patients with renal insufficiency also experience a greater number of hemorrhagic complications associated with antiplatelet therapy than individuals with normal renal function. This review focuses on the benefits and risks of antiplatelet therapy in patients with impaired kidney function suffering from an acute coronary syndrome.

The efficacy and safety of short- and long-term dual antiplatelet therapy in patients with mild or moderate chronic kidney disease: results from the Clopidogrel for the Reduction of Events During Observation (CREDO) trial

BACKGROUND

Mild and moderate chronic kidney disease (CKD) is associated with decreased survival and increased adverse events after a percutaneous coronary intervention (PCI). Therapy with clopidogrel decreases adverse events in large patient populations. Therefore, we sought to determine the efficacy and safety of long-term clopidogrel therapy in patients with CKD.

METHODS

Two thousand two patients from the CREDO trial in whom an elective PCI of a single or multiple vessels was planned were analyzed. Patients were randomly assigned to a 300-mg loading dose of clopidogrel before PCI followed by clopidogrel 75 mg/d for a year versus a placebo loading dose at the time of the PCI procedure and clopidogrel 75 mg/d for 28 days and placebo for the remainder of a year. Patients were categorized by their estimated creatinine clearance (>90 [normal, n = 999], 60-89 [mild CKD, n = 672], <60 mL/min [moderate CKD, n = 331]).

RESULTS

Diminished renal function was associated with worse outcomes. Patients with normal renal function who received 1 year of clopidogrel had a marked reduction in death, myocardial infarction, or stroke compared with those who received placebo (10.4% vs 4.4%, P < .001), whereas patients with mild and moderate CKD did not have a significant difference in outcomes with clopidogrel therapy versus placebo (mild: 12.8% vs 10.3%, P = .30; moderate: 13.1% vs 17.8%, P = .24). Clopidogrel use was associated with an increased relative risk of major or minor bleeding, but this increased risk was not different based on renal function (relative risk 1.2, 1.3, 1.1).

CONCLUSIONS

Clopidogrel in mild or moderate CKD patients may not have the same beneficial effect as it does in patients with normal renal function, but was not associated with a greater relative risk of bleeding based on renal function. Further studies are needed to define the role of clopidogrel therapy in patients with CKD.

Clopidogrel diminishes hemodialysis access graft thrombosis

BACKGROUND

The most common complication of hemodialysis access graft is thrombosis. Clopidogrel, an inhibitor of platelet aggregation, was assessed to prevent this serious complication.

METHODS

Nineteen patients on chronic hemodialysis whose vascular accesses were grafts were divided into two groups: Group A (n=11, 58%) consisted of patients who did not receive anti-thrombotic therapy after graft placement; Group B (n=8, 42%) received clopidogrel 75 mg/day from two days after surgery onwards. Both groups were well matched with respect to age, gender, cause of renal failure, hematocrit, platelet count and Kt/V. All patients' thrombotic episodes were followed up from the day of graft surgery until thrombosis was diagnosed. Finally, the survival difference between both groups was determined.

RESULTS

Ten thrombotic episodes were diagnosed in Group A while no events were reported in Group B (p<0.001). Graft access days of patency were significantly more in Group B than in Group A (350.8+/-166 vs 86.8+/-69, p<0.001). The time elapsed from dialysis initiation to graft placement was not different (Group A: 18+/-12 days; Group B: 20+/-10 days). Days in hemodialysis were different between both groups (Group A: 195.9+/-96; Group B: 545.5+/-291, p<0.001) and all patients of Group A (n=11, 57.9%) and two patients of Group B (25%) died (p=0.001). No major bleeding events were reported.

CONCLUSIONS

Clopidogrel significantly decreased thrombotic graft episodes. Patients on clopidogrel had a prolonged vascular access patency, longer time on hemodialysis and longer survival.

Clopidogrel Diminishes Hemodialysis Access Graft Thrombosis

BACKGROUND

The most common complication of hemodialysis (HD) access graft is thrombosis. Clopidogrel, an inhibitor of platelet aggregation, was assessed to prevent this serious complication.

METHODS

A prospective study in which 24 patients on chronic HD whose vascular accesses were grafts were divided into two groups: group A (n = 12, 50%) consisted of patients who did not receive antithrombotic therapy after graft creation, and group B (n = 12, 50%) received clopidogrel 75 mg/day from 2 days after surgery onwards. Both groups were not different according to age, gender, cause of renal failure, hematocrit levels, platelet counts and Kt/V. All patients' thrombotic episodes were followed up from the day of graft surgery until thrombosis was diagnosed. Finally, the patient survival difference between both groups was determined.

RESULTS

Eleven thrombotic episodes were diagnosed in group A while one event was reported in group B (p < 0.001). Graft access days of patency were significantly longer in group B compared to group A (380.8 +/- 170 vs. 90.1 +/- 57.2, p < 0.001). Time that elapsed from dialysis initiation to graft creation was not different (group A 18 +/- 12 days, group B 20 +/- 10 days). Days on HD were different between both groups (group A 208.9 +/- 97.2 vs. group B 583.2 +/- 287.0, p < 0.001) and all patients from group A (n = 12, 100%) and 2 patients from group B (16.7%) died (p = 0.001). Major bleeding events were not reported.

CONCLUSIONS

Clopidogrel significantly decreased thrombotic graft episodes. Patients on clopidogrel had a prolonged vascular access patency, longer time on HD and better survival.

Treatment of acute coronary syndromes in patients who have chronic kidney disease

Patients with CKD and CAD have traditionally been a difficult population to diagnose and treat in the setting of ACS. In addition to having poorer outcomes post-ACS, data are lacking regarding best treatments available. Aggressive interventional and medical treatments in this group with already poor outcomes are not necessarily contraindicated and should always be considered. The appalling outcome for CKD patients post-ACS is improved by many therapies shown to benefit in the non-CKD patients. Data suggest that troponins are useful markers in CKD patients, that major bleeding is not increased with the use of GP IIb-IIIa antagonists, that thrombolytics have been used successfully in CKD patients, and that PCI electively and as a primary treatment for ACS is successful and probably more beneficial to treatment.

Cardiovascular disease in chronic kidney disease from a cardiologist's perspective

PURPOSE OF REVIEW

Cardiovascular disease accounts for the majority of morbidity and mortality in patients with chronic kidney disease (CKD). This review therefore concentrates on CKD from the viewpoint of the cardiologist.

RECENT FINDINGS

Studies have identified several explanations for this observation, including high rates of risk factors for cardiovascular disease, lesser use of cardioprotective strategies, adverse outcomes with cardiovascular drugs and procedures, and accelerated atherosclerosis and myocardial disease in CKD. Because recent studies have rigorously controlled for confounding factors, there is an emerging recognition that CKD is an independent cardiovascular risk state. Conversely, CKD appears to be the result of systemic atherosclerosis. The relative under-utilization of cardioprotective therapies has been an increasingly reported finding in the literature. It appears that conventional cardiovascular risk factor reduction in both the chronic and acute care settings has a greater relative benefit in those patients with CKD than in those with normal renal function.

SUMMARY

CKD is an independent cardiovascular risk state. Hence, there is a strong rationale for research in CKD patients into the pathogenesis of CVD. In addition, there are multiple opportunities for improving cardiovascular outcomes in patients with CKD, including both chronic and acute cardiovascular risk reduction.

Opportunities for improvement in the cardiovascular care of patients with end-stage renal disease

Cardiovascular disease accounts for the majority of morbidity and mortality in patients with end-stage renal disease (ESRD). Studies have identified several explanations for this observation, such as high rates of cardiovascular risk factors, lesser use of cardioprotective strategies, adverse outcomes with cardiovascular drugs and procedures, and accelerated atherosclerosis and myocardial disease in ESRD. Based on these findings, this article addresses the critical opportunities for improvement in cardiovascular outcomes in patients with ESRD. These improvements include prevention of cardiovascular events, management of acute coronary syndromes and heart failure, and the prevention of sudden death.

Frequency of nonresponse antiplatelet activity of clopidogrel during pretreatment for cardiac catheterization

Platelet function was evaluated before and after clopidogrel therapy in 50 cardiology candidates scheduled for intervention; results were averaged from optical platelet aggregation with 2 significantly correlated point-of-care instruments, Thrombelastograph and Ichor PlateletWorks. Although this was a limited study with few complications, the failure of clopidogrel therapy (30% nonresponders with <10% average platelet inhibition) was not correlated with clinical pretreatment variables, including atorvastatin therapy, postintervention bleeding complications, or major adverse coronary events.

Clopidogrel’s role in the management of atherosclerotic disease: a focus on acute coronary syndromes

Recent advances in our understanding of the role of the platelet in the atherosclerotic process beyond the acute formation of arterial blood clots, such as inflammation, have highlighted the role of antiplatelet agents as being much more than just 'blood thinners.' Some of the most important cardiovascular trials performed in the last 20 years have studied antiplatelet therapies. However, despite their long history, current global health implications and proven benefit, there remain substantial gaps in our understanding as to how to best utilize the limited number of antiplatelet agents available. This article will discuss the mechanism of action of the antiplatelet class known as thienopyridines, the pharmacodynamics and pharmacokinetics of the thienopyridine agent clopidogrel (Plavix, Bristol-Myers Squibb and Sanofi Pharmaceuticals) as well as the literature supporting its clinical benefits and areas of ongoing research that will help clarify the optimal utilization of clopidogrel for the treatment of cardiovascular disease.

Review of antithrombotic agents used for acute coronary syndromes in renal patients

Management issues in acute coronary syndromes (ACSs) with regard to patients with renal insufficiency or failure are complex. Renal patients have a greater risk for bleeding compared with those with normal renal function because of prolonged bleeding time and platelet dysfunction. Some of the drugs used have significant renal excretion, such as the glycoprotein IIb/IIIa receptor antagonists. Additionally, thrombolytics are underused, which contributes to the delay in instituting immediate treatment of acute myocardial infarction. Clinical data regarding the optimum management of ACSs in renal patients are still lacking. In this article, we review the available data on the use of antithrombotic agents, particularly in patients with renal impairment.

Randomized controlled trial of clopidogrel plus aspirin to prevent hemodialysis access graft thrombosis

Thrombosis of hemodialysis vascular access grafts represents a major medical and economic burden. Experimental and clinical models suggest a role for antiplatelet agents in the prevention of thrombosis. The study was designed to determine the efficacy of the combination of aspirin and clopidogrel in the prevention of graft thrombosis. The study was a randomized, double-blind trial conducted at 30 hemodialysis units at Veterans Affairs medical centers. Participants undergoing hemodialysis with a polytetrafluoroethylene graft in the arm were randomized to receive either double placebos or aspirin (325 mg) and clopidogrel (75 mg) daily. Participants were to be monitored while receiving study medications for a minimum of 2 yr. The study was stopped after randomization of 200 participants, as recommended by the Data Safety and Monitoring Board because of a significantly increased risk of bleeding among the participants receiving aspirin and clopidogrel therapy. The cumulative incidence of bleeding events was significantly greater for those participants, compared with participants receiving placebos [hazard ratio, 1.98; 95% confidence interval (CI), 1.19 to 3.28; P = 0.007]. Twenty-three participants in the placebo group and 44 participants in the active treatment group experienced a bleeding event (P = 0.006). There was no significant benefit of active treatment in the prevention of thrombosis (hazard ratio, 0.81; 95% CI, 0.47 to 1.40; P = 0.45), although there was a trend toward a benefit among participants who had not experienced previous graft thrombosis (hazard ratio, 0.52; 95% CI, 0.22 to 1.26; P = 0.14). In the hemodialysis population, therapy with aspirin and clopidogrel was associated with a significantly increased risk of bleeding and probably would not result in a reduced frequency of graft thrombosis.

Management of heart failure and coronary artery disease in patients with chronic kidney disease

Cardiovascular disease (CVD) is a major contributor to the mortality and morbidity of patients who suffer from chronic kidney disease (CKD). Heart failure and ischemic heart disease (IHD) are both highly prevalent in this population. The diagnosis of myocardial dysfunction is usually based on echocardiography. As in the general population, systolic dysfunction is treated with a combination of diuretics, renin-angiotensin system blockade, and beta-receptor antagonists. Diastolic dysfunction is best managed by eliminating the cause. Non-invasive tests for coronary artery disease (CAD) may be less reliable in patients with renal disease compared with nonuremic patients. Medical therapy of IHD in this population is generally similar to that for other patient groups, but surgical revascularization appears to carry a higher risk of complications with poorer clinical outcomes. The choice of revascularization procedure (coronary artery bypass grafting versus percutaneous transluminal angioplasty) should be based on the specific coronary anatomy of a given patient as well as a consideration of other comorbid factors.

Coronary artery disease in uremia: Etiology, diagnosis, and therapy

Cardiovascular disease is a major challenge to nephrologists, whether we deal with patients with pre-end-stage renal failure, on dialysis or after successful renal transplantation. It is the most common cause for death in patients with a functional allograft, and prevents many dialysis patients from being engrafted. Coronary artery disease is a diagnostic and therapeutic challenge, as it differs in some respects from that seen in non-uremic cohorts, and lacks much of the evidence-base on which therapeutic intervention rests. This review examines the experimental and clinical literature on cardiovascular disease in uremia, focusing on coronary artery disease. We focus on the incidence, presenting syndromes, screening tools, and interventions in the context of acute and chronic coronary syndromes. Recent evidence comparing coronary angioplasty, coronary artery stenting, and bypass surgery in subjects with renal failure is also reviewed. Coronary artery disease is more prevalent in uremia, more difficult to diagnose and less rewarding to treat compared to non-uremic subjects. Many more randomized trials are needed. In the absence of information from such trials, we advocate aggressive control of conventional and novel cardiovascular risk factors, and early intervention for symptomatic coronary disease.