Catheter Angiography (CA)

A catheter angiography (CA) is a minimally invasive test that uses x-rays and a contrast material to produce pictures of blood vessels for diagnosis and treatment.

Angiograms are done to detect or confirm abnormalities within the blood vessels in the brain, including:

• An aneurysm, bulge or sac that develops in an artery due to weakness of the arterial wall
• Arteriovenous malformation, a tangle of dilated blood vessels that disrupts normal blood flow in the brain
• Carotid stenosis, narrowing of the carotid arteries
• Brain tumour
• Blood clot
• Vasculitis, an inflammation of the blood vessels
• Vascular dissection, a tear in the artery wall
• Stroke
• Evaluation of arteries of the brain and neck before surgery
• In preparation for minimally invasive treatment of a vessel abnormality
• Additional information on abnormalities seen on Magnetic Resonance Imaging (MRI) or Computed Tomography (CT) scans

Frequently Asked Questions

How should I prepare for the procedure?

• Inform our staff if you are/have:
  • Pregnant
  • Any allergies, especially to contrast materials or anaesthetic medications
• You may be advised to stop certain medications like aspirin and blood thinners
• Do not eat or drink for 4 to 6 hours before the test
• Breastfeeding patients may consider pumping milk ahead of time
• Have a relative or friend accompany you

What to expect during the procedure?

• Your doctor would have discussed this test with you in advance and a written consent will be needed
• Before the test, empty your bladder
• Devices will be used to monitor your blood pressure, breathing and heart rate
• Next, you will be asked to lie down where your groin area is shaved and cleaned. You will be covered from
  the shoulders down with a sterile drape
• Local anaesthetic will be given at the groin

Figure 1 Preparation for CA

• A small cut is made in the skin for a long, thin and hollow plastic tube (catheter) to be inserted
• Contrast material is injected through the catheter. You may feel a hot sensation and a metallic taste in your
  mouth that lasts a few seconds
• Images are taken using x-rays
• After the test, the catheter is removed and the wound is bandaged
• The test may take up to an hour but may vary. Remain still throughout the test

What happens after the procedure?

• You will be sent to your ward
• For the next 6 hours, lie down and keep your legs straight to prevent bleeding from the wound
• Inform the nurse if there is bleeding, swelling or pain at the site where the catheter was inserted
• You may resume your normal diet immediately or as advised by your doctor
• You may engage in light activities 6 hours after the test, but avoid exercise and strenuous activities for 3 days

Other procedures may follow after a CA:

Embolisation

• Closing the aneurysm by filling it with a material (coil, or flow-diverting stent) to reduce the risk of bleeding
• Blocking abnormal blood vessels to reduce blood supply in patients with tumour before surgery

Figure 2 Closing an aneurysm sac by filling it with a coil

Endovascular Therapy

• Non-surgical treatment for the sudden loss of brain function due to blood clots

Carotid Stenting

• Deployment of a metal mesh tube (stent) into the carotid artery to treat narrowing of the vessel and decrease the risk of stroke

Figure 3 Stent in vessel

What are the benefits, risks and limitations?

Benefits

• No radiation remains in the body after the scan
• Usually no side effects
• Use of a catheter makes it possible to combine diagnosis and treatment in a single procedure
• Detailed, clear and accurate images of blood vessels in the brain
• May produce more accurate results than a Carotid Doppler Ultrasound or other non-invasive methods

Risks

• Bruising/bleeding at the wound
• Injury to the blood vessel
• Kidney damage in patients with impaired kidney function
• Allergy to contrast medium
• Infection
• Stroke if the catheter dislodges plaque from a vessel wall that blocks blood flow within the brain, but it is rare

Limitations

• Patients with impaired kidney function and/or allergy to contrast materials may not be suitable for this test
• Pregnant patients are advised not to have a CA unless necessary