Anticoagulation therapy during haemodialysis: a comparativestudy between two heparin regimensAlaa Sabry, Moammer Taha, Mamdouh Nada, Fawzan Al Fawzanand Khalid Alsaran
Low-molecular-weight heparins have been suggested as
sodium use (1.40 W 0.28 tinzaparin sodium versus
providing well tolerated, efficient, convenient and possibly
1.23 W 0.28 for UFH) without any change in the
more cost-effective anticoagulation for haemodialysis than
haemodialysis prescription. The total cost of 24-week use of
unfractionated heparins (UFHs). A single-bolus dose at the
tinzaparin sodium was 23% more expensive compared with
start of haemodialysis effectively prevents clot formation in
that of UFH. Tinzaparin sodium should be considered as an
the dialyser and air trap with fewer side effects and possible
effective, well tolerated and may be a superior alternative to
benefits on uraemic dyslipidaemia. The safety, clinical
conventional heparin anticoagulation in haemodialysis.
efficacy and cost of two anticoagulation regimens in 23
However, at least – on the short term – tinzaparin sodium
haemodialysis patients were compared over 12-month
therapy did not affect lipid profile in haemodialysis patients.
period. The study comprised two stages: the first stage in
Currently, the direct cost in Saudi Arabia is a little more than
which UFH was used for 6 months and the second stage in
standard heparin by about 23%. Blood Coagul Fibrinolysis
which UFH was replaced by tinzaparin sodium. The
20:57 –62 ß 2009 Wolters Kluwer Health | Lippincott
relationship between the anticoagulant effect of tinzaparin
sodium and clinical clotting during haemodialysis was
recorded. Clinical clotting (grades 1– 4) was evaluated byvisual inspection after blood draining of the air trap every
Blood Coagulation and Fibrinolysis 2009, 20:57–62
hour and by inspection of the dialyser after each session. The costs and effects of both anticoagulant protocols on the
Keywords: anticoagulation, haemodialysis, lipids, low-molecular-weight
lipid profile were also compared. Anticoagulation with
tinzaparin sodium resulted in less frequent dialyser and air-
Prince Salman Center for Kidney Disease, Riyadh, Saudi Arabia
trap clotting compared with UFH (P U 0.001 and 0.04,
Correspondence to Dr Alaa Sabry, Prince Salman Center for Kidney Disease,
respectively). Over 24 weeks, no changes in standard serum
lipid profiles were observed. There was statistically
significant improvement in dialysis adequacy – evidenced
Received 27 April 2008 Revised 20 July 2008
by improved single-pool Kt/V 6 months after tinzaparin
LMWHs do not deplete plasma lipase to the same extent
Haemodialysis requires anticoagulation to avoid clotting
as UFHs however, their effect on uraemic dyslipi-
of the dialyser and extracorporeal circuit. Hitherto, the
daemia is controversial with some but not all
anticoagulation regimen has consisted of an intravenous
(i.v.) bolus dose of unfractionated heparin (UFH) fol-lowed either by i.v. continuous infusion or a new bolus
Although there are several reported studies comparing a
dose during dialysis. However, low-molecular-weight
variety of LMWHs with UFHs in haemodialysis patients,
heparins (LMWHs) are being frequently used as they
experience with tinzaparin sodium is limited. In this cross-
were reported to have several potential advantages over
over study, we compared the clinical efficacy, safety and
UFHs The risk of bleeding is lower with LMWHs
cost effectiveness of tinzaparin sodium with UFH in 23
than with UFHs as LMWHs interact less with platelets
chronic renal failure patients stabilized on haemodialysis.
and the vessel wall The risk of heparin-inducedthrombocytopaenia is also less In addition, the admin-
istration is practical, and the effect on the blood lipids
may be more favourable LMWHs act longer than
Twenty-three adult patients (17 men and six women)
UFHs and can be given as a single-bolus injection at
with end-stage renal disease (ESRD) maintained on
the start of the dialysis session. LMWHs are as effective
as UFHs in preventing thrombosis in animal models andcause less blood loss than UFHs. However, these findings
Patients received haemodialysis thrice weekly for 3–4 h
have not been confirmed in clinical studies
per session at blood flow rates of 250–350 ml/min, with a
0957-5235 ß 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins
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polysulphone hollow-fibre filter (F7 HPS; Fresenius,
prior to cessation of haemodialysis. Activated coagulation
Germany). Vascular access was via a native arteriovenous
times were monitored and heparin dose was modified
fistula, an artificial graft or permanent permcath, patients
accordingly to maintain times around 200 s early in the
were older than 18 years and chronic haemodialysis was
haemodialysis session and 150 s later in the session.
Patients with known bleeding disorders, anaemia with
During this stage, 1656 haemodialysis sessions were
haemoglobin (Hb) level below 10 g/dl, recent trauma,
carried out, the anticoagulation profile was changed to
surgery, infectious disease or haemorrhagic disorders
tinzaparin sodium. The starting dose was calculated as
(<1 month), receiving oral or other forms of anticoagulant
40–50% of the total UFH previously used during the first
therapy (e.g. warfarin, aspirin) or drugs that could affect
stage, according to manufacturer’s instruction. The dose
heparin activity (e.g. tetracyclines, digitalis and antihis-
was modified (increased or decreased) in case of clotting
or bleeding in steps of 500 anti-Xa IU until a satisfactorydose is obtained. It was administered 3–4 min before
Patients continued their usual medication (including
dialysis as a bolus dose, injected into the arterial line
lipid-lowering therapy in some) and were treated in
predialyser. Anticoagulation was monitored by visual
the normal manner. Moreover, the individual diet habit
inspection of the arterial air trap every 30–60 min.
was maintained throughout the trial that prevented anysignificant change in the BMI and serum albumin level.
Laboratory estimations and blood sampling
Human recombinant erythropoietin dose was given when
Blood specimens were taken from the arterial line after
necessary to maintain target haemoglobin of 11–12 g/dl.
lowering the blood flow to 100 ml/min for 1 min.
They were subjected to two stages, in each stage, a
different anticoagulation regimen during haemodialysis
Total cholesterol (TC), high-density lipoprotein choles-
was used (each stage was of 6 months duration).
(LDL-c) and triglyceride concentrations were measured
on a high-throughput autoanalyser (Dimension X band)
During this stage, 1656 haemodialysis sessions were
using reagents supplied by Dade Behring (Eschborn,
carried out, the anticoagulation regimen consisted of
Germany). Complete blood count, single pole Kt/V was
UFH (sodium heparin 5000 IU/ml) administered as a
also measured before and after each stage of the anti-
bolus dose (50 IU/kg body weight) i.v. into the predia-
coagulant protocol. The protocol was approved by our
lyser arterial line of the extracorporeal blood circuit at the
start of haemodialysis, followed by a maintenance dose of1000 IU heparin per hour. Infusion was discontinued 1 h
Clinical clottingDuring each stage, clinical clotting was evaluated by
Demographic criteria for 23 patients included in our study
visual inspection of air trap after blood draining everyhour. Air-trap clotting was graded from 1 to 4 (grade 1, no
clotting in the trap; grade 2, fibrinous ring; grade 3, clot
formation and grade 4, coagulated system) by visual
inspection of the dialyser at the end of each session.
Dialyser clotting was graded from 1 to 4 [grade 1, clean
filter; grade 2, a few blood stripes (affecting less than 5%
of the fibres seen at the surface of the dialyser); grade 3,
many blood stripes (affecting more than 5% of the fibres)
Variables are given as mean Æ SD unless otherwise
stated. Chi-squared test was used to compare the pre-
valence of nonparametric variables, whereas differences
between variables were analysed by paired Student’s t
test or Mann–Whitney test as deemed appropriate. A
P value of less than 0.05 was considered statistically
significant. All analysis was performed using the Statis-tical Package for Social Science (SPSS, Inc., Chicago,
CHF, congestive heart failure; DM, diabetes mellitus; HTN, hypertension; IHD,ischaemic heart disease.
Illinois, USA) version 10.0 for Windows.
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Anticoagulation therapy during haemodialysis Sabry et al.
Comparison between unfractionated heparin (UFH) and
A total of 3312 haemodialysis sessions were studied in 23
tinzaparin regarding air-trap clotting grades
patients over a period of 12 months.
Our study included 23 patients (17 men and six women).
Their age, original renal disease, disease duration, hae-modialysis duration, comorbid conditions and currentmedications are given in
patients and grade 3 clotting in seven patients duringUFH
(P ¼ 0.001). No episode of grade 4 clotting (coagulated
No statistically significant differences were observed
filter) was observed in either treatment protocol (as
regarding standard serum lipids (TC, LDL-c, triglyceride
and HDL-c), Hb, white blood cells count and plateletcount after changing from UFH to tinzaparin sodium
Tinzaparin sodium use was accompanied by minorhaemorrhage between dialyses in three patients after
the first and second dialysis session. Prolonged bleeding
To determine whether the type of anticoagulation had
from the arteriovenous fistula (AVF) puncture sites in two
any effect on dialyser uraemic solute clearance single-
patients that necessitated prolonged compression and
pool Kt/V urea values were obtained. There was statisti-
protamine sulphate infusion, epistaxis in the third patient
cally significant improvement in dialysis adequacy –
was managed by anterior nasal pack. These events did
evidenced by improved single-pool Kt/V 6 months after
tinzaparin sodium use (1.40 Æ 0.28 for tinzaparin sodiumuse versus 1.23 Æ 0.28 6 months after UFH use,
P ¼ 0.008) without any change in the haemodialysis pre-
The mean cost of use of tinzaparin sodium/patient for 6
months (67.57 Æ 25.42 US$) was significantly higher ascompared with that of UFH (51.2263 Æ 23.91 US$),
Air-trap clottingGrade 1 clotting was observed in 10 and 14 patients,
whereas grade 2 clotting was observed in only one patient
The mean dose of tinzaparin sodium per session remains
and grade 3 clotting was observed in 12 and eight patients
relatively constant with minor modification over the trial
during UFH and tinzaparin sodium use, respectively
(P ¼ 0.04). No episode of grade 4 clotting (coagulatedsystem) was observed in either treatment protocol (as
LMWHs are derivatives of commercial UFHs preparedby enzymatic or chemical hydrolysis. They have been
prepared to have a mean molecular weight of 4000–
Grade 1 clotting was observed in 15 and 21 patients,
5000 Da (the mean molecular weight of UFHs ranged
whereas grade 2 clotting was observed in one and two
from 10 000–16 000 Da). Like UFHs, LMWHs inactivate
Biochemical criteria for 23 patients included in our study
P1, between starting and 6 months after UFH; P2, 6 months after switching to tinzaparin. ALT, alanine aminotransferase; AST, aspartate aminotransferase; HDL, high-density lipoprotein; LDL, low-density lipoprotein; UFH, unfractionated heparin; WBCs, white blood cells. M Statistically significant.
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Comparison between unfractionated heparin and
tinzaparin regarding dialyzer clotting grades
Heparin and tinzaparin dose/ session over 6 months
factor Xa, but they have a lesser effect on thrombin
session (units mean SD)
because most of the molecules do not contain enough
saccharide units to bind to form the ternary complex in
which thrombin and anti-thrombin III are bound simul-taneously. LMWHs have been proposed to cause less
Doses of tinzaparin and unfractionated heparin/session over 6 months
bleeding and less thrombocytopaenia than UFHs. On the
contrary, LMWHs were reported to be expensive andhave generally not been found to be superior to UFHs interms of dialysis-related bleeding or other complications.
The annual cardiovascular disease mortality in ESRDpatients on haemodialysis is 9.5%, which is 35 times
UFH has been the established anticoagulant for haemo-
higher than in the general population . The charac-
dialysis for several decades. However, in the past 15 years,
teristic perturbations in lipoprotein metabolism are con-
many reports on the use of LMWH for anticoagulation in
sidered as a risk factor for high cardiovascular mortality
general, and for haemodialysis in particular, have been
rates in these patients . Common dyslipidemic
published There is consistency among these studies
changes include increases in triglycerides, very low-
regarding their beneficial anticoagulant effects ,
density lipoproteins (VLDLs), intermediate-density
nevertheless there is no consensus on their favourable
lipoproteins (IDLs) and remnant lipoproteins, increases
effects on the lipid profile in such category of patients.
Although the benefits of LMWH over standard UFH in
The primary cause for the accumulation of triglyceride-
the treatment and prophylaxis of venous thromboembo-
enriched lipoproteins and atherogenic-dense LDLs in
lism are well established, the relative merits of LMWH
patients on haemodialysis is not fully understood. In
for haemodialysis coagulation are less clear. The ease
ESRD patients, decreased lipoprotein lipase (LPL)
administration of LMWH (single-bolus predialysis)
activity may largely contribute to the generation of
and lack of laboratory monitoring would seem clear
atherogenic-dense LDLs . Repeated administration
of heparin for anticoagulation during haemodialysiscauses depletion of LPL and may exhaust lipolytic
The primary purpose of anticoagulation during haemo-
capacity, whereas LMWH was reported to release LPL
dialysis is of course the prevention of thrombosis in the
from the vessel wall to a lesser extent . As a result,
extracorporeal circuit, and in this respect, in our study
lipolytic potential are expected to increase gradually over
tinzaparin sodium was more effective than UFH – over
months with subsequent beneficial effects on atherogenic
1656 haemodialysis sessions – evidenced by significantly
lipid particles if patients are switched from UFH to
less air trap and dialyser clotting. This is in agreement
with the observations of several investigators who havenoticed similar beneficial anticoagulant effect of LMWH
Preliminary studies with LMWH suggested beneficial
effects on the lipid metabolism of haemodialysis patients,but this has not been supported by later larger studies, atleast in the short term
Comparison between unfractionated heparin and
tinzaparin regarding cost, air-trap and dialyzer clotting
In our study, we did not observe significant improvement
on lipid metabolism of any element of lipid profile6 months after tinzaparin sodium therapy, which is in
agreement with other studies. Kronenberg et al.
failed to observe any beneficial effects on lipid profile
in 153 haemodialysis patients treated with three different
LMWH preparations (dalteparin, sandoparin and enox-
a Values are given in mean Æ SD. M Statistically significant.
aparin) compared with a similar number of patients
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Anticoagulation therapy during haemodialysis Sabry et al.
treated with UFH over at least 6 months, even after
lysis in our study was 23% higher than that of UFH,
allowing for sex, age and diabetes mellitus.
which is in agreement with previous reports
Hombrouckx et al. reported no beneficial effects on
The major limitations of our study include the relatively
cholesterol or triglyceride concentrations using three
small study population, the short duration, it was not
LMWH preparations in a month study that included
specifically a dose-finding study and including also
36 patients. Furthermore, in a longer term study carried
patients with diabetes mellitus, as well as the lack of a
out by Spaia et al. including 30 haemodialysis
control group, and finally the lack of factor X level assay
patients who switched from UFH to enoxaparin, a sig-
during the second stage of the study.
nificantly lower HDL and higher triglyceride concen-trations after 33 months of the LMWH treatment was
The present study was performed with tinzaparin sodium
observed. Of note is that the lipid parameters returned
and any generalization to other LMWH should be
to baseline in the 10 patients switched back to UFH for
inferred with caution as the pharmacology of each
6 months. In the latter two studies mentioned
above, enoxaparin was given both as an initial bolusand as a continuous infusion during the haemodialysis
session. It is therefore possible that differences in
Tinzaparin sodium should be considered as effective and
the mode of administration may have a bearing on
well tolerated and may be a superior alternative to
differences found between studies In our study,
conventional heparin anticoagulation in haemodialysis.
tinzaparin sodium was administered as a bolus dose
However, at least – on the short term – tinzaparin sodium
prior to haemodialysis. An important point in relation
therapy did not improve lipid profile in haemodialysis
to our lipid findings should be noted; care was taken not
patients. Currently, the direct cost in Saudi Arabia is a
to alter any of the patients’ lipid-lowering therapies or
little more than standard heparin by about 23%. How-
ever, with more widespread usage, the price of tinzaparinsodium is likely to reduce and the small extra cost is
However, it should be noted that the beneficial effect of
counterbalanced by the convenience of administration.
LMWH was reported not to occur with all preparations ofLMWH that were used, nor was it seen in normolipi-
daemic patients on haemodialysis. Notably, heparin
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“HEARTLESS EXPLOITATION OF THE POOR AND SUFFERING”? Note: Center Discussion Papers are preliminary materials circulated to stimulate Abstract The decision to require that countries grant product patents for pharmaceutical innovations as a condition of membership in the World Trade Organization was verycontentious. Almost fifty developing countries were not granting patent monopolies for
English books 1. Kaku K, Matsuda M, Kaneko T, Permutt MA: Genetic analysis of diabetic susceptibility in inbred mouse strains. In Tai Hee Lee (Ed) Recent advances in insulin therapy pp.127㹼 130, Springer International (Heidelberg, Germany), 1990. 2. Matsuda M, DeFronzo RA : In vivo Measurement of Insulin Sensitivity in Human Clinical Research in Diabetes and Obesity In Draznin B, Rizza R (Ed)