Operative Planning

Special Equipment

• As for retrograde percutaneous femoral artery puncture
  
• 6.0 to 6.5 French (F) sheath
  
• 6 Fr guiding catheter
  
• Over the wire microcatheters
  
• 0.035-in guide wire and micro–guide wires
  
• 5F catheter and guide wire (for diagnostic angiogram) and 6 to 7F catheter and guide wires (for coil embolization).
  
• Microballoon catheter for balloon remodeling and/or stents as necessary

Anesthetic Issues

• In awake patients, the diagnostic portion of the procedure can be done under local anesthetic with conscious sedation
  
• In unconscious or patients with impaired level of consciousness, general anesthesia is used for all portions of the procedure
  
• General anesthesia is highly recommended for the coil procedure to allow for optimal imaging
  
• Protamine should be readily available if intraoperative rupture occurs

Positioning

• The patient is placed in the supine position
  
• Intravenous antibiotics, if needed, are given
  
• A Foley catheter is placed
  
• The proper shielding is placed on the patient
  
• Both inguinal areas are shaved and prepped with iodine solution
  
• A sterile drape is placed over the prepped areas
  
• The head is positioned in neutral position and gently taped in place

• A four-vessel diagnostic angiogram is performed with all views necessary to determine aneurysm morphology and its association with the parent artery and its branches.
  
• Using a common femoral approach, the region over the right femoral head is examined under fluoroscopy to determine the appropriate entry site into that artery.
  
• The skin and subcuticular tissues over the artery is as infiltrated with the appropriate local anesthetic: 1% lidocaine and 0.5% bupivacaine hydrochloride in a 50:50 mixture.
  
• The artery is entered with a 19-gauge single-wall needle, and on the brisk return of bright arterial blood, a Benson wire is inserted through the needle and advanced into the abdominal and thoracic aortas under direct fluoroscopic guidance.
  
• A 5F sheath is placed over the guide wire; this is then sutured to the skin and perfused with heparinized saline throughout the entirety of the procedure.
  
• A 5F diagnostic catheter is then advanced over the abdominal and thoracic aortas under direct fluoroscopic guidance is used to access the patient’s brachiocephalic vessels.
  
• Anteroposterior and lateral angiographic images of the head are obtained.
  
• A rotational angiographic image of the head is obtained of the parent artery of interest with a machine injection of contrast. Acquisition of these rotationally acquired angiographic images is sent to the three-dimensional workstation, where reconstruction is performed.
  
• Following this angiogram, the 5F intravascular sheath is exchanged for a 6.5F sheath over a guide wire that is then sutured to the skin.
  
• The patient is heparinized during the coiling portion of the procedure, and this is maintained throughout the procedure (activated clotting time checked hourly and heparin adjusted accordingly to maintain a baseline of 2 to 3 times the baseline); some centers begin heparin at the start of the procedure and other centers wait until the first coil is placed.
  
• A 6F guiding catheter is advanced into the appropriate internal carotid artery. For left sided lesions in patients with difficult arches this may need to be done over an exchange wire.
  
• A variety of guide wires and catheters are used to access the aneurysm under direct fluoroscopic and digital roadmap guidance.
  
• The microguidewire is then removed, and detachable platinum coils are advanced through the microcatheter into the aneurysmal sac.
  
• The largest coil is used first to form the initial frame, and smaller coils are then used to occlude the aneurysm.
  
• Proximal and distal radiopaque markers on the microcatheter are used to maintain the catheters position and angiography is used prior to each coil release to assess coil position stability and patency of the parent vessel as well as for any evidence of rupture as evidenced by contrast extravasation.
  
• The coil placement is continued to increase density until resistance is met and the microcatheter can be repositioned to deliver further coils if it is felt that there unfilled or poorly packed regions.
  
• It is critical to avoid displacement of the microcatheter into the thin aneurysm wall which may lead to immediate rupture.

• In giant and wide neck aneurysms, occasionally an over-the-wire micro-balloon catheter is inserted through a larger guiding catheter to cover the aneurysm neck during coil deployment. The balloon is intermittently inflated during coil deployment and prior to detachment to asses for coil stability.
  
• Giant, wide neck, or fusiform PCOM artery aneurysms that are not suitable for clipping may receive endovascular PCOM artery parent vessel sacrifice.

Stents and Embolization

• Patients that fail balloon occlusion, or with aneurysm architecture that is amenable, may be candidates for stenting assisted coil embolization.
  
• Small aneurysms may rarely thrombose following stent deployment without coil embolization.
  
• A stent allows the insertion of embolic coils through the stent interstice or through a catheter “trapped” into the aneurysm along side the deployed stent as it may be difficult to pass the microcatheter through the stent interstices.

Sheath Removal

• The sheath is removed.
  
• The arteriotomy is closed with a closure device after the patient is given intravenous antibiotics.
  
• Heparin is routinely continued at some centers for 24 to 48 hours, and is not continued and allowed to wear off naturally at others.