2. Heparin for patency of AV fistula
coagulation state, the site of the fistula, type of the site and those who were not accessible for the
fistula, the technique of the operation and the drugs postoperative follow up were excluded.
being used. Using the anticoagulant drugs and The patients were randomly divided in two
dilators during or after the operation yet remains groups. Randomization was achieved using sealed
controversial (2-4). envelopes: group 1 received 5000 IU of heparin
Early failure in the function of arteriovenous intravenously (after dissection and before anastomosis);
fistula is the most common complication reported in the control group did not receive any drug. The
these patients. This can be the result of thrombosis patency of the arteriovenous fistula was then
or insufficient blood flow due to technical problems observed in different periods: after the operation, and
or the characteristic of the artery or vein used. 2 weeks following the operation in an outpatient
Diabetic patients were shown to be more prone to clinic. In each visit patency of the arteriovenous
thrombosis (5). fistula checked and evaluation was done for any
Prior studies were unable to show an acceptable complications. The patency of the arteriovenous
report on the efficacy of heparin in patients who had fistula controlled by touching the thrill and
undergone an operation to establish an arteriovenous auscultation the bruit.
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fistula. In addition, most of them had been carried The gathered data were entered in computer.
out retrospectively (6-10). The aim of this study was Statistical analysis was performed by computer
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to evaluate the effect of the heparin on the patency of employing Chi square and Student’s t test in the
the arteriovenous fistula. SPSS program.
MATERIALS AND METHODS RESULTS
of
This prospective interventional study was performed A total of 198 patients were enrolled in this study:
from November 2003 through May 2005 in vascular 96 (48.5%) in case and 102 in control group. The
surgery ward in Imam Reza Hospital. After approval mean age of the patients in case and control groups
in our Institutional Ethics Committee, the patients was 48.4 ± 14.5 and 48.5 ± 16.4 years, respectively.
ive
who underwent a surgery in order to perform an There was no significant difference in the age of the
arteriovenous fistula in brachio-cephalic (cubital) or two groups (P = 0.941).
snuffbox (radio-cephalic) areas for the hemodialysis Out of 123 males enrolled in this study, 60
means were enrolled. We obtained informed consent (48.8%) were classified in group 1 (cases) and 63
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from all patients. (51.2%) in group 2 (controls); where as for the
The suitable vessel for anastomosis was selected females this results was 36 (48%) versus 39 (52%).
based on the physical examination findings. Veins There was no a statistically significant correlation
greater than 2 mm in size were considered as between gender and heparin injection in this study (P
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suitable. In addition, palpation of radial and ulnar = 0.915).
pulses prior to anastomosis was necessary. The The frequency of the heparin injection in patients
patients with a positive history of coagulopathy and with different sites of arteriovenous fistula is
vasculitis, those with an arteriovenous fistula in an demonstrated in Table 1. No significant relation was
area rather than brachio cephalic or snuffbox, those found between the site of arteriovenous fistula and
with a prior attempt to perform a fistula in the same heparin injection (P = 0.128).
Table 1. The frequency of the heparin injection in patients with different sites of arteriovenous fistula
Received heparin Did not received heparin
Site of Arteriovenous fistula Frequency Percent Frequency Percent Total
Left brachio-cephalic 26 40.6 38 59.4 64
Left snuff box (radio-cephalic) 55 59.8 37 40.2 92
Right brachio-cephalic 10 47.6 11 52.3 21
Right snuff box (radio-cephalic) 11 52.4 10 47.6 21
380 Acta Medica Iranica, Vol. 46, No. 5 (2008)
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3. H. Ravari et al.
Table 2. The patency of arteriovenous fistula in each group immediately and in 2 weeks of the surgery*
Patency of arteriovenous fistula Received heparin Did not received heparin
Immediately after the surgery Patent 86 (89.6) 89 (87.3)
Failure 10 (10.4) 103 (12.7)
Two weeks following the surgery Patent 82 (85.4) 143 (74.5)
Failure 14 (14.6) 49 (25.5)
*Data are given as number (percent).
Patency rate of arteriovenous fistula in the ward The effect of the heparin on the survival of the
was 89% in heparin group and 87% in the control vascular bypass has been observed in two studies;
group; this difference was not found to be significant Ascer et al. suggested heparin to be an important
(P = 0.609). therapeutical component in cases of synthetic
In addition, the patency rate 2 weeks after the infrapopliteal bypass, which should be prescribed in
surgery was 85% in heparin group versus 74% of the all these cases (5). Similarly, in another study carried
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other group, resulting in a statistically significant out in Pennsylvania, heparin was shown to improve
difference (P = 0.046). Table 2 outlines the patency the outcome of the operation in cases with distal
rate in each group in the ward and 2 weeks of the infrapopliteal synthetic bypass that needed additive
surgery.
During this study hematoma occurred in four
cases (three cases in heparin group and one in
control group). There was no significant difference
between the frequency of the hematoma in each
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arteriovenous fistula (6).
Present prospective interventional study has
compared the patency rate of arteriovenous fistula in
two intervals, early and 2 weeks after the surgery. A
patent arteriovenous fistula was reported in 89.6%
of
group (P = 0.173). There was no evidence of heparin and 87.3% of group 1 and 2 early after the operation
induced thrombocytopenia. while the result was changed to 85.4% versus 74.5%
in 2 weeks following the surgery. The difference
DISCUSSION between the two groups was found to be significant
ive
after 2 weeks (P value = 0.046). The arteriovenous
Heparin inhibits the coagulation. Effect of heparin fistula became non-functional in three of the four
on the patency of arteriovenous fistula has not been cases who developed hematoma (two cases in
clarified in literature. However, the effect of heparin heparin group and one in control group).
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in preventing arteriovenous fistula’s thrombosis has In conclusion, this study has shown a higher
been appraised indirectly in several studies. Rollo et patency rate of arteriovenous fistulas in patients who
al. have compared the effect of heparin, aspirin and had received heparin intraoperatively. In other
dipyridamole in preventing the thrombosis in words, according to this study, intravenous intra-
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arteriovenous fistula (3). In another study, the operative injection of heparin is recommended in the
predictive factors for accomplishing a patent patients who need an arteriovenous fistula.
arteriovenous fistula were observed. In this study,
the technique of the operation rather than the heparin
injection was reported to be the most important Acknowledgement
factor in influencing this success (6). We are indebted to the Research and Development
Ciancio et al. have reported several cases of Center of Sina Hospital for their support.
iatrogenic arteriovenous fistula as vascular
complications in transplant surgeries. Heparin
therapy was suggested in theses patients because Conflict of interests
they had a relatively higher risk of thrombosis in the The authors declare that they have no competing
transplanted organ (4). interests.
Acta Medica Iranica, Vol. 46, No. 5 (2008) 381
www.SID.ir
4. Heparin for patency of AV fistula
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