Comparison of low molecular weight heparin to standard heparin in hemodialysis/hemofiltration

Anticoagulation for people receiving long-term haemodialysis

BACKGROUND

Haemodialysis (HD) requires safe and effective anticoagulation to prevent clot formation within the extracorporeal circuit during dialysis treatments to enable adequate dialysis and minimise adverse events, including major bleeding. Low molecular weight heparin (LMWH) may provide a more predictable dose, reliable anticoagulant effects and be simpler to administer than unfractionated heparin (UFH) for HD anticoagulation, but may accumulate in the kidneys and lead to bleeding.

OBJECTIVES

To assess the efficacy and safety of anticoagulation strategies (including both heparin and non-heparin drugs) for long-term HD in people with kidney failure. Any intervention preventing clotting within the extracorporeal circuit without establishing anticoagulation within the patient, such as regional citrate, citrate enriched dialysate, heparin-coated dialysers, pre-dilution haemodiafiltration (HDF), and saline flushes were also included.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to November 2023 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-randomised controlled studies (quasi-RCTs) evaluating anticoagulant agents administered during HD treatment in adults and children with kidney failure.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias using the Cochrane tool and extracted data. Treatment effects were estimated using random effects meta-analysis and expressed as relative risk (RR) or mean difference (MD) with 95% confidence intervals (CI). Evidence certainty was assessed using the Grading of Recommendation, Assessment, Development and Evaluation approach (GRADE).

MAIN RESULTS

We included 113 studies randomising 4535 participants. The risk of bias in each study was adjudicated as high or unclear for most risk domains. Compared to UFH, LMWH had uncertain effects on extracorporeal circuit thrombosis (3 studies, 91 participants: RR 1.58, 95% CI 0.46 to 5.42; I2 = 8%; low certainty evidence), while major bleeding and minor bleeding were not adequately reported. Regional citrate anticoagulation may lower the risk of minor bleeding compared to UFH (2 studies, 82 participants: RR 0.34, 95% CI 0.14 to 0.85; I2 = 0%; low certainty evidence). No studies reported data comparing regional citrate to UFH on risks of extracorporeal circuit thrombosis and major bleeding. The effects of very LMWH, danaparoid, prostacyclin, direct thrombin inhibitors, factor XI inhibitors or heparin-grafted membranes were uncertain due to insufficient data. The effects of different LMWH, different doses of LMWH, and the administration of LMWH anticoagulants using inlet versus outlet bloodline or bolus versus infusion were uncertain. Evidence to compare citrate to another citrate or control was scant. The effects of UFH compared to no anticoagulant therapy or different doses of UFH were uncertain. Death, dialysis vascular access outcomes, blood transfusions, measures of anticoagulation effect, and costs of interventions were rarely reported. No studies evaluated the effects of treatment on non-fatal myocardial infarction, non-fatal stroke and hospital admissions. Adverse events were inconsistently and rarely reported.

AUTHORS' CONCLUSIONS

Anticoagulant strategies, including UFH and LMWH, have uncertain comparative risks on extracorporeal circuit thrombosis, while major bleeding and minor bleeding were not adequately reported. Regional citrate may decrease minor bleeding, but the effects on major bleeding and extracorporeal circuit thrombosis were not reported. Evidence supporting clinical decision-making for different forms of anticoagulant strategies for HD is of low and very low certainty, as available studies have not been designed to measure treatment effects on important clinical outcomes.

Executive summary of the Korean Society of Nephrology 2021 clinical practice guideline for optimal hemodialysis treatment

The Korean Society of Nephrology (KSN) has published a clinical practice guideline (CPG) document for maintenance hemodialysis (HD). The document, 2021 Clinical Practice Guideline on Optimal HD Treatment, is based on an extensive evidence-oriented review of the benefits of preparation, initiation, and maintenance therapy for HD, with the participation of representative experts from the KSN under the methodologists' support for guideline development. It was intended to help clinicians participating in HD treatment make safer and more effective clinical decisions by providing user-friendly guidelines. We hope that this CPG will be meaningful as a recommendation in practice, but not on a regulatory rule basis, as different approaches and treatments may be used by health care providers depending on the individual patient's condition. This CPG consists of eight sections and 15 key questions. Each begins with statements that are graded by the strength of recommendations and quality of the evidence. Each statement is followed by a summary of the evidence supporting the recommendations. There are also a link to full-text documents and lists of the most important reports so that the readers can read further (most of this is available online).

Executive Summary of the Korean Society of Nephrology 2021 Clinical Practice Guideline for Optimal Hemodialysis Treatment

The Korean Society of Nephrology (KSN) has published a clinical practice guideline (CPG) document for maintenance hemodialysis (HD). The document, 2021 Clinical Practice Guideline on Optimal HD Treatment, is based on an extensive evidence-oriented review of the benefits of preparation, initiation, and maintenance therapy for HD, with the participation of representative experts from the KSN under the methodologists’ support for guideline development. It was intended to help clinicians participating in HD treatment make safer and more effective clinical decisions by providing user-friendly guidelines. We hope that this CPG will be meaningful as a recommendation in practice, but not on a regulatory rule basis, as different approaches and treatments may be used by health care providers depending on the individual patient’s condition. This CPG consists of eight sections and 15 key questions. Each begins with statements that are graded by the strength of recommendations and quality of the evidence. Each statement is followed by a summary of the evidence supporting the recommendations. There is also a link to full-text documents and lists of the most important reports so that the readers can read further (most of this is available online).

An Adjustable Dalteparin Sodium Dose Regimen for the Prevention of Clotting in the Extracorporeal Circuit in Hemodialysis: A Clinical Trial of Safety and Efficacy (the PARROT Study)

Background:

Dalteparin sodium, a low-molecular-weight heparin, is indicated for prevention of clotting in the extracorporeal circuit during hemodialysis (HD). Product labeling recommends a fixed single-bolus dose of 5000 international units (IU) for HD sessions lasting up to 4 hours, but adjustable dosing may be beneficial in clinical practice.

Objective:

The aim of the PARROT study was to investigate the safety and efficacy of an adjustable dose of dalteparin in patients with end-stage renal disease requiring 3 to 4 HD sessions per week.

Design:

A 7-week, open-label, multicenter study with a single treatment arm, conducted between October 2013 and March 2016.

Setting:

Ten sites in Canada.

Patients:

A total of 152 patients with end-stage renal disease requiring 3 to 4 HD sessions per week.

Measurements:

The primary outcome was the proportion of HD sessions completed without premature termination due to inadequate anticoagulation.

Methods:

All participants initially received a dose of 5000 IU dalteparin, which could be adjusted at subsequent HD sessions when clinically indicated, by increment or decrement of 500 or 1000 IU, with no specified dose limits.

Results:

Patients were followed for 256 patient-months. Nearly all (99.9%; 95% confidence interval [CI]: 99.7-100) evaluable HD sessions were completed without premature clotting. Dose was adjusted for more than half (52.3%) of participants, mostly owing to clotting or access compression time >10 minutes. Median dalteparin dose was 5000 IU (range: 500-13 000 IU). There were no major bleeds, and minor bleeding was reported in 2.3% of all HD sessions. There was no evidence of bioaccumulation.

Limitations:

This short-term study, with a single treatment arm, was designed to optimize dalteparin dose using a flexible dosing schedule; it was not designed to specifically evaluate dalteparin dose minimization, provide a direct comparison of dalteparin versus unfractionated heparin, or provide information on long-term safety for flexible dalteparin dosing. Patients were excluded if they were at high risk of bleeding, including those on anticoagulants and those on antiplatelet agents other than aspirin <100 mg/d.

Conclusions:

Overall, an adjustable dalteparin sodium dose regimen allowed safe completion of HD, with clinical benefits over fixed dosing.

Trial Registration:

ClinicalTrials.gov NCT01879618, registered June 13, 2013.

Correlation between activated partial thromboplastin time and anti-Xa activity in patients who received low-molecular weight heparin as anticoagulation for haemodialysis

Plasma anti-Xa activity, the recommended test to monitor low-molecular weight heparin (LMWH) therapy, is not readily available in many laboratories. In our clinical trials on the use of LMWH as anticoagulation for haemodialysis, a consistent prolongation of APTT in addition to the elevated anti-Xa activity was observed in the patients after LMWH administration. Hence, the paired anti-Xa activity and APTT data were re-analyzed. The APTT ratio, which was the proportional change in APTT from the baseline value after LMWH administration, was found to have a strong correlation with anti-Xa activity (coefficient of determination, R ²  = 0.72, P < 0.001). In the receiver operating characteristic analysis, the APTT ratio was also found to be an excellent predictor of therapeutic anti-Xa activity ≧0.5 IU/mL (area under curve = 0.93, P < 0.001). The sensitivity was 88% and the specificity was 83.3% when an APTT ratio ≧1.4 was used as the cut point to predict the achievement of therapeutic anti-Xa activity. Our results illustrated that APTT is a potentially useful screening test to assess the degree of anticoagulation achieved by LMWH during haemodialysis, if the testing for plasma anti-Xa activity is not available.

Use of Single Dose Low-Molecular-Weight Heparin in Long Hemodialysis

Low-molecular-weight (LMW) heparin has recently been used for anti-coagulation in maintenance hemodialysis. The LMW heparin was administered as a single bolus in hemodialysis that usually lasted for four hours or less. The regimen for administering LMW heparin in hemodialysis of longer duration (5 hours or more) is not well documented and manufacturers recommend a supplementary dose equivalent to one-quarter of the initial dose to be given at 4 hours after the commencement of hemodialysis. In this study, we explored whether administering a single dose of LMW heparin is feasible in hemodialysis of longer duration. Maintenance five-hour hemodialysis sessions were performed in nine uremic patients with two different heparin regimens: single dose of LMW heparin (nadroparin) 12,500 ICU AXa at the beginning of dialysis or a priming dose of nadroparin 10,000 ICU AXa at the beginning of dialysis followed by a supplementary dose of nadroparin 2,500 ICU AXa at the beginning of the fifth hour of dialysis. Clots in the airtraps or clotting of the dialyser were not observed in hemodialysis with the single dose heparin regimen. The anti-Xa activities at different time intervals during dialysis were above the therapeutic range of 0.5 U/ml except towards the end of the hemodialysis treatment. There was no difference between anti-Xa activities determined in dialysis sessions using two different regimens of LMW heparin at any individual time interval. The anti-throm-botic effect determined by the area under the time response curve for anti-Xa activity was comparable in the two LMW heparin regimens. Hence, our findings suggest a single bolus dose of LMW heparin (nadroparin) at 12,500 ICU AXa provides adequate, safe, and effective anti-coagulation for five-hour hemodialysis. This practice is convenient and avoids the necessity of administering a double dose of LMW heparin.

Safety of low-molecular-weight heparin compared to unfractionated heparin in hemodialysis: a systematic review and meta-analysis

BACKGROUND

Low molecular weight heparins (LMWH) have been extensively studied and became the treatment of choice for several indications including pulmonary embolism. While their efficacy in hemodialysis is considered similar to unfractionated heparin (UFH), their safety remains controversial mainly due to a risk of bioaccumulation in patients with renal impairment. The aim of this systematic review was to evaluate the safety of LMWH when compared to UFH for extracorporeal circuit (ECC) anticoagulation.

METHODS

We used Pubmed, Embase, Cochrane central register of controlled trials, Trip database and NICE to retrieve relevant studies with no language restriction. We looked for controlled experimental trials comparing LMWH to UFH for ECC anticoagulation among end-stage renal disease patients undergoing chronic hemodialysis. Studies were kept if they reported at least one of the following outcomes: bleeding, lipid profile, cardiovascular events, osteoporosis or heparin-induced thrombocytopenia. Two independent reviewers conducted studies selection, quality assessment and data extraction with discrepancies solved by a third reviewer. Relative risk and 95% CI was calculated for dichotomous outcomes and mean weighted difference (MWD) with 95% CI was used to pool continuous variables.

RESULTS

Seventeen studies were selected as part of the systematic. The relative risk for total bleeding was 0.76 (95% CI 0.26-2.22). The WMD calculated for total cholesterol was -28.70 mg/dl (95% CI -51.43 to -5.98), a WMD for triglycerides of -55.57 mg/dl (95% CI -94.49 to -16.66) was estimated, and finally LDL-cholesterol had a WMD of -14.88 mg/dl (95% CI -36.27 to 6.51).

CONCLUSIONS

LMWH showed to be at least as safe as UFH for ECC anticoagulation in chronic hemodialysis. The limited number of studies reporting on osteoporosis and HIT does not allow any conclusion for these outcomes. Larger studies are needed to evaluate properly the safety of LMWH in chronic hemodialysis.

Clinical study on low-molecular weight heparin infusion as anticoagulation for nocturnal home haemodialysis

AIM

This study was conducted to evaluate low-molecular weight heparin (LMWH) as anticoagulation for nocturnal home haemodialysis (NHHD). While its longer half-life may cause drug accumulation in frequent dialysis, the essential need of a supplementary intra-dialytic bolus for the sleeping patients also renders LMWH's use impractical.

METHODS

The recruited patients, who were on alternate-day 8 h haemodialysis, were randomized to receive either nadroparin or unfractionated heparin (UFH) for a week. They underwent crossover to receive the alternate anticoagulant in the next week. A nadroparin infusion regimen was adopted to enhance its practicability, which consisted of a loading dose of 35 IU/kg and a continuous infusion of 10 IU/kg per hour for 6 h.

RESULTS

A total of 12 NHHD patients were recruited. With nadroparin infusion, the mean anti-Xa levels at the 2^nd , 4^th , 6^th and 8^th hours of dialysis were 0.46 ± 0.11, 0.55 ± 0.14, 0.61 ± 0.15 and 0.45 ± 0.15 IU/mL respectively. Comparing to UFH, which offered satisfactory anticoagulation according to the activated partial thromboplastin time, nadroparin-treated dialysis achieved similar thrombus scores and dialyser urea/creatinine clearances at the end of haemodialysis. During the post-dialysis period, one patient demonstrated residual LMWH effect (anti-Xa level 0.09 IU/mL) on the next day, whereas none had detectable anti-Xa activities 2 days afterwards upon next dialysis.

CONCLUSIONS

Low-molecular weight heparin infusion is practical and effective as anticoagulation for NHHD. It can be safely used in an alternate-day haemodialysis schedule. A close monitoring for LMWH accumulation is recommended if long dialysis is performed daily.

Vitamin E-Coated and Heparin-Coated Dialyzer Membranes for Heparin-Free Hemodialysis: A Multicenter, Randomized, Crossover Trial

BACKGROUND

Hemodialysis requires effective anticoagulation to avoid blood circuit clotting. In patients at high risk for bleeding, several alternative methods have been developed.

STUDY DESIGN

Multicenter, prospective, randomized, crossover study evaluating the noninferiority of vitamin E-coated compared with heparin-coated dialyzers in a 4-hour heparin-free hemodialysis strategy.

SETTINGS & PARTICIPANTS

32 adult long-term hemodialysis patients from 2 French hemodialysis units with well-functioning fistulas or double-lumen catheters.

INTERVENTION

Patients were randomly allocated to a first period using either vitamin E- or heparin-coated dialyzers. After a washout period of 2 hemodialysis sessions, each patient was switched to the alternative dialyzer for a second period. Each study period started with 2 hemodialysis sessions with reduced heparin dose (50% and 25% of usual heparin dose, respectively, for sessions 1 and 2) followed by 2 heparin-free sessions.

OUTCOMES

The primary end point was the percentage of successful study periods, defined as no circuit-clotting event leading to premature interruption of any of the 4 dialysis sessions. Secondary end points included total number and cumulative duration of hemodialysis sessions without clotting, number of saline solution flushes, dialysis circuit bubble trap status and dialyzer membrane status by visual inspection, and dialysis adequacy.

RESULTS

The percentage of success with vitamin E-coated dialyzers (25/32 study periods [78%]) was not inferior to that with heparin-coated dialyzers (26/32 study periods [81%]). Visual inspection showed equal numbers of clean dialysis circuit bubble traps (vitamin E-coated, 34/121; heparin-coated, 32/120), whereas clean fiber bundles were more frequently noted with the vitamin E-coated compared with heparin-coated dialyzers (25/121 vs 2/120; P=0.002).

LIMITATIONS

Results may not extrapolate to critically ill patients. Differences in dialyzer transparency may account for visual inspection scores.

CONCLUSIONS

The success rate of 4-hour heparin-free hemodialysis sessions is lower than that previously claimed in uncontrolled studies. Vitamin E-coated and heparin-coated dialyzers exposed patients to similar and unacceptable high failure rates. Further studies are required to improve heparin-free hemodialysis.

Low-molecular weight heparin infusion as anticoagulation for haemodialysis

Background

Low-molecular weight heparin (LMWH) is commonly used as an anticoagulant for haemodialysis by a single-bolus injection. However, its application in extended haemodialysis has been infrequently studied. In particular, for nocturnal home haemodialysis patients sleeping throughout treatment, the need for additional intradialytic bolus might render the use of LMWH impractical. To overcome this limitation, we changed traditional bolus injections to continuous infusion. We first tested our method among in-centre 4-h haemodialysis patients to establish a feasible and safe infusion regimen before utilizing it in extended dialyses at home.

Methods

Recruited patients were given nadroparin (standardized at 65 IU/kg) as an anticoagulant for haemodialysis. They were first randomized to receive nadroparin either by bolus injection or infusion. Afterwards, the patients underwent crossover to receive the alternate method of LMWH anticoagulation. The degrees of anticoagulation and bleeding complications were compared.

Results

Sixteen haemodialysis patients were recruited. After nadroparin administration, anti-Xa levels at the first hour were significantly higher by the bolus than the infusion methods (0.68 ± 0.10 versus 0.49 ± 0.10 IU/mL, P < 0.001) and were similar by the second hour (0.56 ± 0.10 versus 0.55 ± 0.11 IU/mL, P = 0.64). At the sixth hour, anti-Xa levels by the infusion method were significantly higher (0.35 ± 0.13 versus 0.25 ± 0.10 IU/mL, P < 0.001), suggesting the infusion approach required a dosage reduction. There were no bleeding events reported in either method.

Conclusions

LMWH infusion is feasible and safe. The method avoids early excessive anticoagulation caused by bolus injection and reduces the LMWH dose. Future studies should be conducted to evaluate LMWH infusion in extended haemodialysis treatment.

Efficacy and safety of low molecular weight heparin compared to unfractionated heparin for chronic outpatient hemodialysis in end stage renal disease: systematic review and meta-analysis

Background. Low molecular weight heparin (LMWH) is an effective anti-coagulant for thrombotic events. However, due to its predominant renal clearance, there are concerns that it might be associated with increased bleeding in patients with renal disease.

Objectives. We systematically evaluated the efficacy and safety of LMWH compared to unfractionated heparin (UH) in end stage renal disease (ESRD) patients.

Search Methods. Pubmed, Embase and cochrane central were searched for eligible citations.

Selection Criteria. Randomized controlled trials, comparing LMWH and UH, involving adult (age > 18 years), ESRD patients receiving outpatient, chronic, intermittent hemodialysis were included.

Data Collection and Analysis. Two independent reviewers performed independent data abstraction. I2 statistic was used to assess heterogeneity. Random effects model was used for meta-analysis.

Results. Nineteen studies were included for systematic review and 4 were included for meta-analysis. There were no significant differences between LMWH and UFH for extracorporeal circuit thrombosis [risk ratio: 1 (95% CI [0.62–1.62])] and bleeding complications [risk ratio: 1.16 (95% CI [0.62–2.15])].

Conclusions. LMWH is as safe and effective as UFH. Considering the poor quality of studies included for the review, larger well conducted RCTs are required before conclusions can be drawn.

Uremic toxins and lipases in haemodialysis: a process of repeated metabolic starvation

Severe kidney disease results in retention of uremic toxins that inhibit key enzymes for lipid breakdown such as lipoprotein lipase (LPL) and hepatic lipase (HL). For patients in haemodialysis (HD) and peritoneal dialysis (PD) the LPL activity is only about half of that of age and gender matched controls. Angiopoietin, like protein 3 and 4, accumulate in the uremic patients. These factors, therefore, can be considered as uremic toxins. In animal experiments it has been shown that these factors inhibit the LPL activity. To avoid clotting of the dialysis circuit during HD, anticoagulation such as heparin or low molecular weight heparin are added to the patient. Such administration will cause a prompt release of the LPL and HL from its binding sites at the endothelial surface. The liver rapidly degrades the release plasma compound of LPL and HL. This results in a lack of enzyme to degrade triglycerides during the later part of the HD and for another 3–4 h. PD patients have a similar baseline level of lipases but are not exposed to the negative effect of anticoagulation.

Use and safety of unfractionated heparin for anticoagulation during maintenance hemodialysis

Anticoagulation is essential to hemodialysis, and unfractionated heparin (UFH) is the most commonly used anticoagulant in the United States. However, there is no universally accepted standard for its administration in long-term hemodialysis. Dosage schedules vary and include weight-based protocols and low-dose protocols for those at high risk of bleeding, as well as regional anticoagulation with heparin and heparin-coated dialyzers. Adjustments are based largely on clinical signs of under- and overanticoagulation. Risks of UFH use include bleeding, heparin-induced thrombocytopenia, hypertriglyceridemia, anaphylaxis, and possibly bone mineral disease, hyperkalemia, and catheter-associated sepsis. Alternative anticoagulants include low-molecular-weight heparin, direct thrombin inhibitors, heparinoids, and citrate. Anticoagulant-free hemodialysis and peritoneal dialysis also are potential substitutes. However, some of these alternative treatments are not as available as or are more costly than UFH, are dependent on country and health care system, and present dosing challenges. When properly monitored, UFH is a relatively safe and economical choice for anticoagulation in long-term hemodialysis for most patients.

A multi-center, prospective, open-label, 8-week study of certoparin for anticoagulation during maintenance hemodialysis--the membrane study

Background

Adequate anticoagulation is prerequisite for effective hemodialysis to prevent clotting in the extracorporeal circuit. We aimed providing first data on the efficacy and safety of the low-molecular-weight heparin certoparin in this setting.

Methods

Multicenter, open-label, 8-week trial. Patients received a single dose of 3,000 IU certoparin i.v. with additional titration steps of 600 IU and/or continuous infusion if necessary.

Results

120 patients were screened, 109 enrolled (median age 71; range 26–90 years) and 106 available for efficacy analyses. The percentage of unsatisfactory dialysis results at 8 weeks due to clotting or bleeding, was 1.9% (n = 2/106; 95% confidence interval [CI] 0.23–6.65%); no major bleeding. 1.9% had moderate/severe clotting in the lines/bubble catcher and 2.8% in the dialyser at week 8. 15.7 ± 14.3% of the dialysis filters’ visual surface area was showing redness. In subgroups of patients receiving median doses of 3000 ± 0, 3000 (2400–6000) and 4200 (3000–6600) IU, plasma aXa levels at baseline, 4 and 8 weeks were 0.24 [95%CI 0.21–0.27], 0.33 [0.27–0.40] and 0.38 [0.33–0.45] aXa IU/ml at 2 h. C_48h was 0.01 [0.01–0.02] aXa IU at all visits. At baseline and 4 weeks AUC_0-48h was 2.66 [2.19–3.24] and 3.66 [3.00–4.45] aXa IU*h/ml. In 3.0% of dialyses (n = 83/2724) prolonged fistula compression times were documented. Eight patients (7.34%) had at least one episode of minor bleeding. 4) 85.3% of patients had any adverse event, 9.2% were serious without suspected drug relation; and in 32 patients a drug-relation was suspected.

Conclusions

Certoparin appears effective and safe for anticoagulation in patients undergoing maintenance hemodialysis.

Dyslipidemia associated with chronic kidney disease

Cardiovascular disease is a major cause of morbidity and mortality in patients with impaired renal function. Dyslipidemia has been established as a well-known traditional risk factor for cardiovascular disease (CVD) in the general population and it is well known that patients with chronic kidney disease (CKD) exhibit significant alterations in lipoprotein metabolism. In this review, the pathogenesis and treatment of CKD-induced dyslipidemia are discussed. Studies on lipid abnormalities in predialysis, hemodialysis and peritoneal dialysis patients are analyzed. In addition, the results of the studies that tested the effects of the hypolipidemic drugs on cardiovascular morbidity and mortality in patients with CKD are reported.

Anticoagulation in intermittent hemodialysis: pathways, protocols, and pitfalls

Several methods to prevent extracorporeal circuit clotting during hemodialysis have been used in human medicine. Unfractionated (UF) heparin remains the mainstay of anticoagulant therapy in both human and veterinary intermittent hemodialysis. Different UF heparin regimes may be used depending on the bleeding risk of the patient. In patients with active bleeding or with a recent history of surgery or hemorrhagic episodes, hemodialysis may be performed without any anticoagulation or with regional anticoagulation.

Selection of Anticoagulants for Leukocytapheresis Therapy in Cases of Active Ulcerative Colitis

BACKGROUND AND AIM

Leukocytapheresis (LCAP) is an extracorporeal leukocyte removal therapy that removes immunocompetent leukocytes from the peripheral blood. Nafamostat mesilate (NM) is the most commonly used anticoagulant for LCAP due to various benefits associated with its use, such as a reduced likelihood of bleeding and minimization of adverse reactions caused by contact between blood and the LCAP device. However, adverse reactions have also been reported with NM administration. We reviewed the safety of anticoagulants other than NM, from the perspective of bradykinin production and the consequent drop in blood pressure during treatment.

METHODS

For each of 10 patients with ulcerative colitis, we used four types of anticoagulants sequentially [NM (30-50 mg), heparin, low-molecular-weight heparin (LMWH) and NM (1 mg), and LMWH] for LCAP. We then examined the changes in the blood bradykinin concentrations from the perspective of adverse reactions during LCAP.

RESULTS

The bradykinin production levels from Cellsorba EX varied, depending on the type of anticoagulant used. NM alone (30-50 mg) or LMWH + NM (1 mg) inhibited bradykinin production, whereas heparin alone or LMWH alone significantly accelerated it. However, an excessive fall of blood pressure was not noted in any of the cases. Use of LMWH alone was frequently associated with pressure elevations in the column.

CONCLUSIONS

Given the significant benefits of minimized adverse reactions of LCAP and of continuation of LCAP, we suggest that an appropriate selection of the anticoagulant(s) may allow safer execution of LCAP.

Plasma Lipoprotein Abnormalities in Hemodialysis Patients—Clinical Implications and Therapeutic Guidelines

Patients with advanced stages of chronic kidney disease (CKD) have an increased risk of death from cardiovascular disease (CVD). Dyslipidemias are associated with atherosclerotic vascular changes and the risk of occurrence of acute myocardial infarction in hemodialysis patients. However, management of dyslipidemia in hemodialysis patients does not appear to be actively carried out in routine practice. Presumably, there are three reasons for this reluctance to lipid-lowering in hemodialysis patients. First, there are epidemiological data showing the inverse relationship between cholesterol and mortality rate; a high cholesterol predicts a better survival. Second, lipids are not usually measured using standard fasting serum, but a non-fasting specimen. Third, although hypertriglyceridemia is the most common abnormality, fibrates are contraindicated in patients with renal failure because of a high risk of rhabdomyolysis. These issues are discussed in the current review article. Based on published work, lipid lowering would not increase the death rate if carried out without worsening malnutrition. The National Kidney Foundation K/DOQI Clinical Practice Guidelines recommend a reduction in fasting LDL-C below 100 mg/dL for the prevention of CVD in dialysis patients. Practically, however, the use of non-HDL-C measured by casual blood samples might be sufficient for the risk assessment in many hemodialysis patients. Statins are a good choice for lipid-lowering in dialysis patients. Furthermore, lipoprotein profile might be improved by an inventive use of dialyzer membranes, dialysate solutions, and other dialysis-related medications. For severe hypercholesterolemia, LDL-apheresis is another choice for consideration. Further studies are needed to clearly prove the benefit of lipid reduction in hemodialysis patients and those with CKD at earlier stages.

Factor Xa-activated whole blood clotting time (Xa-ACT) for bedside monitoring of dalteparin anticoagulation during haemodialysis

BACKGROUND

Low molecular weight heparins (LMWH) like dalteparin are increasingly used for anticoagulation during haemodialysis (HD). The available laboratory tests for monitoring LMWH anticoagulation are time-consuming and expensive, and the suitability of the conventional activated clotting time (ACT) is controversial. A simple and cheap bedside test would be useful.

METHODS

We studied the factor Xa-activated whole blood clotting time (Xa-ACT) in vitro and in vivo in nine patients undergoing chronic HD with i.v. dalteparin bolus anticoagulation and compared it with the conventional ACT. Plasma anti-factor Xa (antiXa) activity was determined with a chromogenic assay. Thrombin-antithrombin complexes were measured to detect coagulation activation.

RESULTS

Xa-ACT and ACT were prolonged with rising dalteparin concentration. In vitro, both clotting times were strongly correlated with the antiXa levels (r = 0.94 and 0.89, respectively). Nevertheless, compared with the ACT, the Xa-ACT was considerably more sensitive to the LMWH in vitro (healthy blood: Xa-ACT 90 s/U vs ACT 26 s/U; uraemic blood: Xa-ACT 96 s/U vs ACT 31 s/U) as well as in vivo (Xa-ACT 81 s/U vs ACT 22 s/U) and reflected different intensities of anticoagulation. An initial dalteparin bolus of 80+/-11 U/kg body weight was able to prevent coagulation activation for up to 4 h of HD.

CONCLUSION

For monitoring LMWH anticoagulation the Xa-ACT was superior to the conventional ACT in vitro as well as in vivo during HD. The Xa-ACT can be useful as a LMWH bedside test. The ACT was not sensitive enough to serve as a LMWH monitoring tool.

Anticoagulation during haemodialysis in patients at high-risk of bleeding

Routine haemodialysis is performed with systemic anticoagulation, usually with heparin, to prevent thrombosis in the extracorporeal blood circuit. However, systemic anticoagulation can produce haemorrhagic complications in patients at high risk of bleeding. To minimize the risk of bleeding, a number of alternative regimens have been proposed: regional heparinization with protamine reversal; minimal heparinization; no heparin with saline flushes; regional anticoagulation with citrate; or prostacyclin anticoagulation. Although the incidence of bleeding complications has been reduced, each of these methods has its own limitations and complications. Among the types of membrane used in dialysers, cellulose membranes have been made more biocompatible by attaching N,N-diethyl-aminoehtyl (DEAE) groups to cellulose backbone. Positively charged DEAE groups on Hemophan enable negative charged heparin to be bound with the membrane. Haemodialysis using heparin-bound Hemophan has been reported to be a possible modality for patients at risk of bleeding. We designed more simplified heparin binding technique and have performed haemodialysis using heparin-bound Hemophan in patients at risk of bleeding during the past 7 years. In this review, current strategies to minimize bleeding complications and our experience of haemodialysis using heparin-bound Hemophan will be discussed.

Lower plasma levels of lipoprotein lipase after infusion of low molecular weight heparin than after administration of conventional heparin indicate more rapid catabolism of the enzyme

The functional pool of lipoprotein lipase (LPL) is anchored to heparan sulfate at the vascular endothelium. Injection of heparin releases the enzyme into the circulating blood. Animal experiments have shown that the enzyme is then extracted and degraded by the liver. Low molecular weight (LMW) heparin preparations are widely used in the clinic and are supposed to release less LPL. In this study, we infused a LMW heparin into healthy volunteers for 8 hours. The peak of LPL activity was only about 30% and the subsequent plateau of LPL activity only about 40% compared with those seen with conventional heparin. When a bolus of heparin was given after 4 hours' infusion of LMW or conventional heparin, only relatively small, and similar, amounts of LPL entered plasma. This suggests that the difference between LMW and conventional heparin lay in the ability to retain LPL in the circulating blood, not in the ability to release the lipase. Triglycerides (TGs) decreased when the heparin infusion was started, as expected from the high circulating LPL activities. After 1 to 2 hours, TG levels increased again, and after 8 hours they were about twice as high as before the heparin infusion. This indicates that the amount of LPL available for lipoprotein metabolism had become critically low in relation to TG transport rates. This study indicates that LMW heparin compared with conventional heparin causes as much or more depletion of LPL and subsequent impairment of TG clearing.

Pharmacokinetic studies of dalteparin (Fragmin), enoxaparin (Clexane), and danaparoid sodium (Orgaran) in stable chronic hemodialysis patients

BACKGROUND

Low molecular weight heparins (LMWHs) and danaparoid are an alternative to unfractionated heparin (UH) for anticoagulation during hemodialysis. Few data are available concerning their duration of action and whether drug accumulation occurs with continued use. We performed a prospective randomized study of the pharmacokinetics of dalteparin and enoxaparin plus danaparoid in 21 hemodialysis patients.

METHODS

Patients were randomly assigned to administration of enoxaparin, 40 mg; dalteparin, 2,500 U; or danaparoid, 34 U/kg, for 4 weeks. Antifactor Xa levels were measured at the end of weeks 1 and 4 immediately before the injection and at prescribed intervals up to 48 hours postinjection.

RESULTS

No bleeding or thrombotic episodes occurred during the study. Mean antifactor Xa activities 4 hours postinjection were 0.2 +/- 0.035 (SEM), 0.38 +/- 0.028, and 0.54 +/- 0.051 U/mL week 1 and 0.26 +/- 0.038, 0.40 +/- 0.055, and 0.64 +/- 0.050 U/mL week 4 for dalteparin, enoxaparin, and danaparoid, respectively. Both weeks 1 and 4, antifactor Xa activity 3 hours postdose was significantly greater for danaparoid sodium compared with enoxaparin and dalteparin. There were no significant differences between antifactor Xa activity week 4 versus week 1 for enoxaparin and dalteparin; however, danaparoid sodium levels during dialysis were significantly greater after 4 weeks of treatment (P = 0.0328, 1 hour; P = 0.003, 2 hours; P = 0.0128, 3 and 4 hours).

CONCLUSION

Dalteparin and enoxaparin provide adequate anticoagulation for hemodialysis using single bolus injections at relatively low doses. Danaparoid sodium at the current recommended dosage resulted in greater anticoagulation than enoxaparin or dalteparin and may have an

Dose effect relationship of reviparin in chronic hemodialysis: a crossover study versus nadroparin

Low molecular weight heparins (LMWHs) are used for prevention of clotting in the dialysis circuit. The aim of this trial was to define the optimal dose of a new LMWH and to test the efficiency of a single dose at the start of the session. Fifteen patients were treated according to a double blind and crossover design during 4 blocks of 5 consecutive reviparin doses assigned randomly as 50, 60, 70, 85, and 100 IU anti-Xa/kg. Assessment was carried out on screening of fibrin rings or clots in the arterial and venous air traps and on visual detection of fiber in the dialyzer after rinsing. These clinical results were compared to plasmatic anti-Xa activity and thrombin-antithrombin (TAT) complex generation. A standard dose of 70 IU anti-Xa/kg of nadroparin was used as the control. After a bolus of 50 to 100 IU anti-Xa/kg, the occurrence of fibrin rings and clots in the air traps was dependent on three factors: dose of LMWH, time of the session, and patient status. A bolus of 85 IU anti-Xa/kg of reviparin was effective and safe for sessions of 4 h. For this dose, plasmatic anti-Xa activity was 0.96 +/- 0.28 IU/ml at Hour 2 and 0.82 +/- 0.22 IU/ml at Hour 4. TAT complexes are good markers of the activation of the coagulation. They did not increase during a 4 h session after a reviparin bolus of 100 IU/kg. For the same LMWH dose, the trial shows a great variability of the clinical effect and anti-Xa activities from one patient to another. A single dose of 85 IU anti-Xa/kg of reviparin can be used at the start of the dialysis session as a loading dose. We advise adapting the dose during the subsequent sessions according to the appearance of the blood circuit. The benefit of monitoring anti-Xa activity and TAT complexes could be tested in a further trial.

Dalteparin: an update of its pharmacological properties and clinical efficacy in the prophylaxis and treatment of thromboembolic disease

Dalteparin is a low molecular weight heparin (LMWH) with a mean molecular weight of 5000. Compared with unfractionated heparin (UFH), the drug has markedly improved bioavailability and increased plasma elimination half-life, and exerts a greater inhibitory effect on plasma activity of coagulation factor Xa relative to its effects on other coagulation parameters. Dalteparin also has less lipolytic activity than UFH. Dalteparin 2500U once daily subcutaneously is of similar antithrombotic efficacy to UFH 5000IU twice daily, and 2 studies have shown superiority over UFH 2 or 3 times daily of dalteparin 5000U once daily in patients requiring surgical thromboprophylaxis. After total hip arthroplasty, dalteparin was superior to adjusted-dosage warfarin and was of greater thromboprophylactic efficacy when given for 35 than for 7 days. Intravenous or subcutaneous dalteparin is as effective as intravenous UFH when given once or twice daily in the initial management of established deep vein thrombosis (DVT). The drug is also effective in long term home treatment. Dalteparin has been shown to be effective in combination with aspirin in the management of unstable coronary artery disease (CAD), with composite end-point data from 1 study suggesting benefit for up to 3 months. Current data indicate potential of the drug in the management of acute myocardial infarction (MI). Dalteparin is also of similar efficacy to UFH, with a single bolus dose being sufficient in some patients, in the prevention of clotting in haemodialysis and haemofiltration circuits. Pharmacoeconomic data indicate that overall costs relative to UFH from a hospital perspective can be reduced through the use of dalteparin in patients receiving treatment for venous thromboembolism. Dalteparin has also been shown to be cost effective when used for surgical thromboprophylaxis. Overall, rates of haemorrhagic complications in patients receiving dalteparin are low and are similar to those seen with UFH.

CONCLUSIONS

Dalteparin is effective and well tolerated when given subcutaneously once daily in the prophylaxis and treatment of thromboembolic disease. The simplicity of the administration regimens used and the lack of necessity for laboratory monitoring facilitate home or outpatient treatment and appear to translate into cost advantages from a hospital perspective over UFH or warfarin. Dalteparin also maintains the patency of haemodialysis and haemofiltration circuits, with beneficial effects on blood lipid profiles and the potential for prophylaxis with a single bolus injection in some patients. Data are also accumulating to show dalteparin to be an effective and easily administered alternative to UFH in patients with CAD.

Heparin blunts endotoxin-induced coagulation activation

BACKGROUND

Lipopolysaccharide (LPS) is a major trigger of sepsis-induced disseminated intravascular coagulation (DIC) via the tissue factor (TF)/factor VIIa-dependent pathway of coagulation. Experimental endotoxemia has been used repeatedly to explore this complex pathophysiology, but little is known about the effects of clinically used anticoagulants in this setting. Therefore, we compared with placebo the effects of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) on LPS-induced coagulation.

METHODS AND RESULTS

In a randomized, double-blind, placebo-controlled trial, 30 healthy male volunteers received LPS 2 ng/kg IV followed by a bolus-primed continuous infusion of UFH, LMWH, or placebo. In the placebo group, activation of coagulation caused marked increases in plasma levels of prothrombin fragment F(1+2) (P<0.01) and polymerized soluble fibrin, termed thrombus precursor protein (TpP; P<0.01); TF-positive monocytes doubled in response to LPS, whereas levels of activated factor VII slightly decreased and levels of TF pathway inhibitor remained unchanged. UFH and LMWH markedly decreased activation of coagulation caused by LPS, as F(1+2) and TpP levels only slightly increased; TF expression on monocytes was also markedly reduced by UFH. TF pathway inhibitor values increased after either heparin infusion (P<0.01). Concomitantly, factor VIIa levels dropped by >50% at 50 minutes after initiation of either heparin infusion (P<0.01).

CONCLUSIONS

This experimental model proved the anticoagulatory potency of UFH and LMWH in the initial phase of experimental LPS-induced coagulation. Successful inhibition of thrombin generation also translates into blunted activation of coagulation factors upstream and downstream of thrombin.

Anticoagulation in continuous renal replacement therapy

Continuous renal replacement therapies (CRRTs) allow for gradual solute and fluid removal. In very sick patients with acute renal failure, they may be better tolerated than hemodialysis. The major drawback to CRRTs is the need for anticoagulation to maintain filter patency. The patients who are likely to benefit from CRRTs are also at higher risk for bleeding from systemic anticoagulation. The most commonly used form of anticoagulation for CRRTs, low-dose heparin, causes bleeding in 10-50% of patients. Regional anticoagulation using protamine may reduce the risk of bleeding, but it is difficult to use. Low molecular weight heparin and prostacyclin both may partially reduce bleeding, but are difficult to dose. Regional anticoagulation with citrate is easy to use and has been shown to prolong filter life without systemic anticoagulation. It is the anticoagulant of choice for most patients on CRRT.

Low Molecular Weight Heparin: An Evaluation of Current and Potential Clinical Utility in Surgery

Heparin, a mixture of glycosaminoglycans of various sizes, is a potent natural anticoagulant. Low molecular weight heparins (LMWH) contain only the polymers of smaller size, which appear to possess most of the antithrombotic potential. Pharmacological differences between the two suggest a number of advantages with LMWH therapy. Our objective was to establish the utility of LMWHs in comparison to the current practice of anticoagulation in surgical patients. Articles were obtained through MEDLINE and CURRENT CONTENTS queries. The searches were limited to English and French-language articles and included published overviews containing relevant individual trials. We examined the current literature, consisting of 1,730 published reports from 1979-1998, regarding the biochemistry, pharmacology, physiology, and clinical applications of LMWH in comparison with current therapy. Studies were selected based on their relevance to LMWHs, the size and methods of trials, and their application to clinical care. Peer-reviewed published data were critically evaluated by independent extraction by several authors. Established rules for levels of evidence were used to objectively evaluate the strength of evidence supporting recommendations in each clinical area. LMWHs provide superior anticoagulation in the prophylaxis of DVT following orthopedic, general, and trauma surgery. Further studies should establish which other patients may benefit from such prophylaxis. Current evidence does not support the use of LMWHs in patients with mechanical heart valves or those on mechanical cardiac support devices; however, it may have a role in the maintenance of vascular graft patency. Further studies should examine the role of LMWHs in transplant atherosclerosis, and in patients requiring long-term anticoagulation at high risk for bleeding with warfarin therapy. The economic implications of LMWH administration remain unclear. On the basis of the information presented in this review, LMWHs are promising new agents in prophylaxis and treatment of both arterial and venous thrombosis. In the near future, LMWHs are likely to supplant UFH and perhaps warfarin in many applications.http://link.springer-ny.com/link/service/journals/00547/bibs/8n4p203.html</hea

Successful anticoagulation with dalteparin in a patient with mechanical heart valves

BACKGROUND

Standard thromboprophylaxis of patients with mechanical heart valves is achieved using warfarin. In certain patients this may be very difficult; thus, alternative pharmacotherapy must be used.

OBJECTIVE

To report a case of a patient who successfully used dalteparin, a low-molecular-weight heparin, for anticoagulation.

CASE SUMMARY

A 58-year-old white woman with mechanical aortic and mitral heart valves initially received warfarin for anticoagulation. Thromboprophylaxis was very challenging. Her international normalized ratios (INRs) were erratic and occasionally responded paradoxically to changes in dose. Finally, she experienced a left hemispheric stroke when her INR was extremely subtherapeutic. Subsequently, despite best efforts, her INR again was subtherapeutic; warfarin was discontinued and dalteparin was initiated with daily self-administered subcutaneous injections of 16 000 units. No complications have arisen since initiation of the new pharmacotherapy approximately 18 months ago.

DISCUSSION

The use of low-molecular-weight heparin for the treatment and prevention of venous thromboembolism is well described. There are few reports of its use for thromboprophylaxis of patients with mechanical heart valves. Our patient has been managed successfully with dalteparin.

CONCLUSIONS

Dalteparin was effectively and safely used for the thromboprophylaxis of a patient with mechanical heart valves whose anticoagulation was previously difficult to manage with warfarin. Dalteparin deserves further study in patients who are unable to tolerate warfarin.

Comparison of low-molecular-weight heparin (enoxaparin sodium) and standard unfractionated heparin for haemodialysis anticoagulation

BACKGROUND

Low-molecular-weight heparin (LMWH) has been suggested as providing safe, efficient, convenient and possibly more cost-effective anticoagulation for haemodialysis (HD) than unfractionated heparin, with fewer side-effects and possible benefits on uraemic dyslipidaemia.

METHODS

In this prospective, randomized, cross-over study we compared the safety, clinical efficacy and cost effectiveness of Clexane (enoxaparin sodium; Rhône-Poulenc Rorer) with unfractionated heparin in 36 chronic HD patients. They were randomly assigned to either Clexane (1 mg/kg body weight, equivalent to 100 IU) or standard heparin, and followed prospectively for 12 weeks (36 dialyses) before crossing over to the alternate therapy for a further 12 weeks. Heparin anticoagulation was monitored using activated coagulation times.

RESULTS

Dialysis with Clexane resulted in less frequent minor fibrin/clot formation in the dialyser and lines than with heparin (P<0.001), but was accompanied by increased frequency of minor haemorrhage between dialyses (P<0.001). Clexane dose reduction (to a mean of 0.69 mg/kg) eliminated excess minor haemorrhage without increasing clotting frequencies. Mean vascular compression times were similar in both groups. Over 24 weeks, no changes in standard serum lipid profiles were observed.

CONCLUSIONS

This study suggests that a single-dose protocol of Clexane is an effective and very convenient alternative to sodium heparin, but currently direct costs are about 16% more. We recommend an initial dose of 0.70 mg/kg.

A controlled trial of low-molecular-weight heparin (dalteparin) versus unfractionated heparin as anticoagulant during continuous venovenous hemodialysis with filtration

OBJECTIVE

To compare the efficacy, safety, and cost of fixed-dose low-molecular-weight heparin (dalteparin) with adjusted-dose unfractionated heparin as anticoagulant for continuous hemofiltration.

DESIGN

Prospective, randomized, controlled clinical trial.

SETTING

University-affiliated adult intensive care unit

PATIENTS

All patients requiring continuous hemofiltration for acute renal failure or systemic inflammatory response syndrome (SIRS) were eligible. Fifty-seven patients were enrolled. Eleven were excluded, seven because of major protocol violations and four died before hemofiltration.

INTERVENTIONS

Patients received continuous venovenous hemodialysis with filtration with prefilter replacement at 500 mL/hr and countercurrent dialysate at 1000 mL/hr. Filters were primed with normal saline containing anticoagulant. Dalteparin-treated patients received a commencement bolus of 20 units/kg and a maintenance infusion at 10 units/kg/hr. Heparin-treated patients received a commencement bolus of 2000-5000 units and a maintenance infusion at 10 units/kg/hr, titrated to achieve an activated partial thromboplastin time in the patient of 70-80 secs.

MEASUREMENTS AND MAIN RESULTS

The primary outcome measure--time to failure of the hemofilter--was compared using survival analysis. Twenty-two patients (13 with acute renal failure and nine with SIRS; total, 41 filters) were randomized to heparin. Twenty-five patients (16 with acute renal failure and nine with SIRS; total, 41 filters) were randomized to dalteparin. Mean (SE) activated partial thromboplastin time in the heparin group was 79 (4.3) secs. Mean (SE) anti-factor-Xa activity in the six patients given dalteparin who were assayed was 0.49 (0.07). Mean (SE) prehemofiltration platelet count was 225 (35.5) x 10(9) for heparin and 178 (18.1) x 10(9) for dalteparin (p = .24, unpaired Student's t-test). Mean (SE) prehemofiltration hemoglobin was 11.4 (0.61) g/dL for heparin and 10.6 (0.38) g/dL for dalteparin (p = .31, unpaired Student's t-test).

PRIMARY OUTCOME

There was no significant difference in the time to failure between the two groups (p = .75, log rank test). For dalteparin, Kaplan-Meier (K-M) mean (SE) time to failure of the hemofilter was 46.8 (5.03) hrs. For heparin, K-M mean (SE) time to failure was 51.7 (7.51) hrs. The 95% CI for difference in mean time to failure was -13 to 23 hrs. The power of this study to detect a 50% change in filter life was >90%.

SECONDARY OUTCOMES

Mean (SE) reduction in platelet count during hemofiltration was 63 (25.8) x 10(9) for heparin and 41.8 (26.6) x 10(9) for dalteparin (p = .57, unpaired Student's t-test). Eight patients given dalteparin and four patients given heparin had screening for heparin-induced thrombocytopenia; three of the dalteparin patients and one of the heparin patients were positive (p = 1.0, Fisher's exact test). There were three episodes of trivial bleeding and two episodes of significant bleeding for dalteparin, and there were three episodes of trivial bleeding and four episodes of significant bleeding for heparin (p = .53, chi-square test). The mean (SE) decrease in hemoglobin concentration during hemofiltration was 0.51 (0.54) g/dL for heparin and 0.28 (0.49) g/dL for dalteparin (p = .75, unpaired Student's t-test). The mean (SE) packed-cell transfusion volume during hemofiltration was 309 (128) mL for heparin and 290 (87) mL for dalteparin (p = .90, unpaired Student's t-test). Daily costs, including coagulation assays, of hemofiltration were approximately 10% higher using dalteparin than with heparin.

CONCLUSIONS

Fixed-dose dalteparin provided identical filter life, comparable safety, but increased total daily cost compared with adjusted-dose heparin. Unfractionated heparin remains our anticoagulant of choice for continuous hemofiltration in intensive care.

A single dose of dalteparin effectively prevents clotting during haemodialysis

BACKGROUND

A single bolus dose of LMW heparin at the start of haemodialysis effectively prevents clot formation in the dialyser and bubble trap. However, there are few studies on the appropriate dosage of LMW heparins in haemodialysis. Therefore we examined the relationship between the anticoagulant effect of dalteparin and clinical clotting during haemodialysis.

METHODS

We performed an open, prospective study on the effect of decreasing doses of dalteparin in 12 haemodialysis patients during a total of 84 sessions (4-4.5 h). The normally applied dose of dalteparin in each patient was reduced by 25% for each session down to 50% of initial dose if no clotting was observed. Clinical clotting (grade 1-4) was evaluated by visual inspection after blood draining of the air trap every hour and by inspection of the dialyser after each session and compared to corresponding values for anti-FXa activity and dialysis time. Blood flow and ultrafiltration rate were kept within narrow limits throughout the study.

RESULTS

No episodes of grade 4 clotting occurred, and no session was interrupted. Eighteen episodes of grade 3 clinical clotting (11%) were observed in patients without warfarin treatment, none with an anti-FXa activity >0.43 IU/ml. Oral warfarin treatment reduced the clinical clotting, and only one grade 3 episode was observed in patients on warfarin therapy. Anti-FXa activity and haemodialysis time were the only factors independently correlated to clotting in a logistic regression model.

CONCLUSION

An anti-FXa activity above 0.4 IU/ml after 4 h of dialysis inhibits significant clotting during haemodialysis. A bolus dose of dalteparin of 70 IU/kg usually seems appropriate, but may be reduced in patients on warfarin treatment. Dialysis time is an independent risk factor for clinical clotting.

Apolipoprotein B-containing lipoproteins in renal failure: the relation to mode of dialysis

BACKGROUND

The aim of this study was to establish whether there is a differential effect of mode of dialysis, hemodialysis (HD), or continuous ambulatory peritoneal dialysis (CAPD) on the dyslipidemia of renal failure.

METHODS

The lipoprotein profile was determined in 61 non-diabetic patients on chronic HD (N = 30) and CAPD treatment (N = 31), and in a control group of 27 healthy subjects. The analysis included the measurement of individual apolipoprotein (apo) A- and apo B-containing lipoproteins (LPs) separated by sequential immunoaffinity chromatography. Apo A-containing lipoproteins include lipoprotein A-I with apo A-I and lipoprotein A-I:A-II with apo A-I and apo A-II as the main protein constituents, whereas apo B-containing lipoproteins comprise simple cholesterol-rich lipoprotein B (LP-B), with apo B as the only protein moiety and complex triglyceride (TG)-rich lipoprotein B complex (LP-Bc) particles with apo B, apo A-II, apo C, and/or apo E as the protein constituents.

RESULTS

CAPD patients had significantly higher concentrations of total cholesterol (6.8 vs. 5.1 mmol/liter), low-density lipoprotein (LDL) cholesterol (4.6 vs. 3.2 mmol/liter), TG (2.3 vs. 1.5 mmol/liter), apo B (155.3 vs. 105.7 mg/dl), LP-B (136.0 vs. 91.9 mg/dl), and LP-Bc (19.3 vs. 13.8 mg/dl) than HD patients. Both HD and CAPD patients had significantly higher TG, VLDL cholesterol, apo C-III, and apo E and significantly lower high-density lipoprotein cholesterol, apo A-II, and lipoprotein A-I:A-II levels than control subjects. The distribution of apo C-III in high-density lipoprotein and VLDL-LDL was altered in CAPD patients in comparison with control subjects. This suggests that the removal of TG-rich lipoproteins is less efficient in patients on CAPD. Normotriglyceridemic (NTG; TG < or = 1.7 mmol/liter, 150 mg/dl) CAPD patients had significantly higher levels of TC, LDL cholesterol, apo B, and LP-B than NTG-HD patients. There was little difference in the LP-Bc levels between NTG-CAPD, NTG-HD, and controls. Similarly, hypertriglyceridemic (HTG) CAPD patients had significantly higher TC, LDL cholesterol, apo B, and LP-B levels than HTG-HD patients. The LP-Bc levels were significantly increased in HTG-HD and HTG-CAPD patients compared with controls, but the slightly higher levels in the CAPD patients did not differ significantly from the HD group.

CONCLUSION

CAPD and HD patients have a lipoprotein profile characteristic of renal failure. Patients on long-term CAPD have higher levels of cholesterol-rich apo B-containing lipoproteins unrelated to TG levels. Many patients on CAPD also have a substantial elevation of the plasma concentrations of TG-rich LPs. The clinical significance of increased levels of potentially atherogenic LP-B during CAPD remains to be investigated.

Non-insulin-dependent diabetes mellitus and hypertriglyceridemia impair lipoprotein metabolism in chronic hemodialysis patients

Patients with diabetes mellitus undergoing chronic hemodialysis treatment have the worst outcome on dialysis due to an increased rate of cardiovascular complications. Nearly all patients present with dyslipidemia, a prominent vascular risk factor, probably responsible for the high rate of vascular injury. Since both uremia and diabetes predispose to hypertriglyceridemia, the present study was conducted to investigate the influence of diabetes mellitus and/or hypertriglyceridemia on lipoprotein metabolism in hemodialysis patients. LDL was isolated and characterized from hyper- and normotriglyceridemic diabetic and nondiabetic hemodialysis patients (n = 40; 10 in each group); also, LDL-receptor-dependent uptake and intracellular cholesterol metabolism were studied in HepG2 cells. In addition, scavenger-receptor-mediated uptake was examined in mouse peritoneal macrophages. LDL isolated from nondiabetic normotriglyceridemic hemodialysis patients exhibited impaired cellular uptake via the LDL receptor. Additionally, intracellular sterol synthesis was less inhibited and cholesterol esterification was reduced compared with LDL from healthy control subjects. Reduction of catabolic capacities was more marked in hemodialysis patients who were either diabetic or hypertriglyceridemic and even more pronounced in patients presenting with a combination of both diabetes and hypertriglyceridemia. Hypertriglyceridemic and diabetic patients showed reduced lipase activity and increased LDL oxidation. Furthermore, they accumulated a fraction of small, dense LDL, and LDL was predominantly taken up via the scavenger-receptor pathway in peritoneal macrophages. This study elucidates the distinct influence of diabetes and/or hypertriglyceridemia in hemodialysis patients on cellular LDL metabolism via specific and nonspecific metabolic pathways. Furthermore, it underscores the cumulative impact of these pathologic entities on impairment of lipoprotein metabolism and increase of cardiovascular risk.