Effect of Heparin on Femoral Arterial Sheaths Thrombosis During Diagnostic Coronary Angiography
Condition: Diagnostic Coronary Angiography
Study type: Interventional
Phase: Phase 3

Summary: 
      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.
    

Detailed description: 
      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.
    

Intervention name(s): Heparin
Intervention type(s): Drug
Intervention description(s): unfractionated heparin 2000 unites
Other intervention name(s): unfractionated heparin
Intervention MeSH terms: Heparin; Calcium heparin
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Prevention