General Description

Carotid artery access provides the most direct access to the anteri- or circulation but is fraught with potential hazards and should only be undertaken with extreme care and with proper weighing of the risks and benefits of the intended procedure. Carotid access by direct percutaneous puncture has the advantage of avoiding difficult arch anatomy and tortuosity in the proximal common carotid artery. The risks of direct puncture include dissection, stenosis, or breaking off calcified plaque that can directly cause stroke. For the interventionist, there is the additional hazard of increased radiation from close proximity to the X-ray source.

Indications

Direct carotid access is indicated for anterior circulation procedures wherein aortic arch or common carotid anatomy prevents distal access routes.

Neuroendovascular Anatomy

The common carotid artery is one of four paired afferents to the intracranial vasculature. The common carotid extends from the aortic arch (left) or brachiocephalic artery (right and bovine shared with left common carotid) and bifurcates into the internal and external carotid arteries, usually around the C3-4 vertebral level but with some variability. Patients with severe vasculopathies tend to accumulate atherosclerotic plaque at or near the bifurcation that can be heavily calcified.

Specific Technique and Key Steps

Carotid artery puncture is best used for anterograde access to ipsilateral lesions. Carotid pulses are palpated to identify the target vessel starting approximately 2 cm above the clavicle and traced cephalad to approximately the level of the hyoid cartilage. Whereas access to distal sites can be undertaken with the patient under conscious sedation, carotid access is preferably performed under general anesthesia ( Fig. 5.1 and Video 5.1 ).

1. 
   

   After the neck is prepared and draped, the ultrasound unit is brought into the operative field to positively identify the carotid artery and to trace it as proximally as possible.

   
   
2. 
   

   Once the puncture site has been identified, a local anesthetic is infused into the subcutaneous tissues.

   
   
3. 
   

   Using a single-wall arterial puncture technique under ultrasound guidance, a sonographically opaque microneedle (i.e., 21-gauge micropuncture kit) is advanced into the carotid artery at a 45° angle with the bevel facing up.

   
   
4. 
   

   Once brisk, pulsatile return of bright red blood is established through the micropuncture needle, a 0.010-inch microwire is advanced through the needle. If resistance is noted, the interventionist should stop and redirect the microwire. Once the wire has been advanced several centimeters, fluoroscopy is used to confirm location. The needle is removed, and an intermediate 4–5 French (F) maker sheath dilator is inserted. The introducer is thereafter removed, and a J-wire is inserted through the sheath into the internal carotid artery. The sheath is then exchanged for the procedural sheath of choice. For diagnostic procedures, typically a 5F sheath is chosen; however, the carotid artery can support up to a 9F sheath for intervention. The insertion of larger sheaths ranging from 8 to 9F often requires the use of an intermediate dilator and a stiffer wire to upsize to the final sheath size ( Video 5.1 ).

   
   
5. 
   

   We routinely perform a carotid artery angiographic run before proceeding with the case. We assess for patency, stenosis, dissection, and possible extravasation.