Diagnostic Coronary Angiography Clinical Trial
Official title:
Efficacy of a Single Dose Intravenous Heparin During Diagnostic Angiography in Reducing Sheath-clot Formation: A Randomized Controlled Trial
The project tests the incidence of femoral arterial sheath thrombus formation during diagnostic coronary angiography and effect of intravenous (iv) heparin bolus administration in reducing this risk in comparison to placebo.
PURPOSE:
The purpose of this study was to evaluate the incidence of blood clots in femoral arterial
sheaths during coronary angiographic procedures and the effect of heparin administration on
thrombus formation.
BACKGROUND:
A heparinized saline flushes are used during diagnostic coronary angiography to prevent
thrombus formation within the lumen of the sheath. However, the use of prophylactic
intravenous heparin following the femoral arterial sheath insertion is controversial. The
aim of this study was to evaluate the effectiveness of 2000 units heparin intravenous bolus
versus saline placebo on thrombus formation within arterial sheath during the diagnostic
coronary angiography.
Methods A randomized controlled trial to examine the efficacy of intravenous heparin bolus
compared with placebo in prevention of femoral arterial sheath thrombus formation in
patients undergoing diagnostic coronary angiography.
The study included all adult patients undergoing cardiac catheterization. Eligible patients
were recruited from day-case and in-patients wards of the Prince Sultan Cardiac Centre
(PSCC), Riyadh. Patients with abnormal coagulation profile, abnormal platelet count and
those receiving enoxaparin, or glycoprotein IIb/IIa antagonists were excluded.
Since the coronary interventions require anticoagulation during the procedure, our study was
interested in the diagnostic part. After insertion of femoral arterial sheath one group was
allocated to 2 milliliter solution containing 2000 units of heparin and the other group to
similar amount of placebo solution which is blinded to both patient and operating
catheterization laboratory staff. Arterial access was obtained via femoral approach and 6F
to 7F Sheaths were used. The femoral sheath was aspirated and flushed for presence of
thrombi or obstruction after each catheter exchange and at the end of the procedure. Two
steps aspiration was performed where 5 cc of blood were extracted in one syringe then
another saline filled syringe was used for flushing. We used clean white gauze to look for
presence of thrombi, and if thrombi were noticed further aspiration was performed followed
by saline flush. Any visible thrombus at any stage of the procedure was considered positive.
The patients evaluated and assessed clinically during hospital stay for presence of leg
ischemia, Femoral and Pedal pulses, Local hematoma or bleeding.
All patients gave informed consent, and the study protocol was approved by the PSCC Ethics
Committee.
Randomization Patients were randomized based catheterization laboratory flow, where the
first laboratory assigned to treatment number one and the second laboratory assigned to
treatment number two on alternate days, sealed and labeled syringes that contained the
treatment allocation came from pharmacy on daily basis and handled to an independent
laboratory staff nurse assigned to maintain concealed to patients and healthcare providers
Throughout the study. The labels were uncovered opened only after the femoral puncture and
arterial sheath insertion confirmed and the patient had provided written informed consent to
participate in the study. Once the seal was broken, the patient was considered irrevocably
randomized.
Study Interventions Patients were randomized to receive either heparin or placebo. Patients
in the heparin group received 2000 units (2 ml) of unfractionated heparin intravenous bolus.
Those randomized to the placebo received 2ml of saline based solution intravenous bolus.
The femoral sheath was aspirated and flushed for presence of thrombi or obstruction after
each catheter exchange and at the end of the procedure. Two steps aspiration was performed
where 5 cc of blood were extracted in one syringe then another saline filled syringe was
used for flushing. We used clean white gauze to look for presence of thrombi, and if thrombi
were noticed further aspiration was performed followed by saline flush. Any visible thrombus
at any stage of the procedure was considered positive. The patients evaluated and assessed
clinically during hospital stay for presence of leg ischemia, Femoral and Pedal pulses,
Local hematoma or bleeding.
Outcomes The primary end point was the occurrence of arterial sheath thrombi, defined as Any
visible thrombus during sheath blood aspiration at any stage of the procedure. The second
primary end point was efficacy of intravenous heparin bolus in reducing the risk of thrombus
formation.
Patients were monitored for embolic and bleeding events until they were discharged from the
hospital. Embolic events defined as appearance of symptoms and signs of acute limb ischemia
like acute leg pain and loss of pedal pulses that result in interventional or surgical
exploration. Bleeding events was defined as local femoral access bleeding or hematoma that
led to surgical exploration.
The diagnosis of embolization or hematoma was made clinically (loss of arterial pulse or
evidence of leg ischemia) and confirmed by Doppler studies when appropriate.
Outcomes were assessed by the patients' treating physicians, who were aware of treatment
assignment.
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Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Investigator, Outcomes Assessor), Primary Purpose: Prevention