General Description

Neurointerventionists are turning to alternative vascular access routes because of patient body habitus, complex anatomy, and the risks associated with traditional femoral artery approaches. This follows a general trend in which the cardiology literature is increasingly adopted in the neurointerventional field. Understanding the anatomy of the upper arms, as well as indications and potential pitfalls for brachial artery access, will allow neurointerventionists to achieve optimal benefits through this access route.

Indications

Brachial access is indicated when intervention requires the use of large-bore guide catheters and if the patient’s habitus makes femoral artery access either difficult or high-risk. Furthermore, anatomic considerations, such as accessing the vertebral artery or aortic arch calcification, can make brachial access superior to transfemoral routes.

Neuroendovascular Anatomy

The brachial artery is the major blood vessel of the upper arm. It is a continuation of the axillary artery that traverses the cubital fossa. Distally, it separates into the radial and ulnar arteries. The median nerve lies in close proximity to the brachial artery and crosses the medial side of the artery anterior to the elbow.

Specific Technique and Key Steps

A complete examination of the upper-extremity vasculature should be performed, including palpating the brachial, ulnar, and radial arteries, as well as checking for capillary refill ( Fig. 3.1 and Video 3.1 ). For ergonomic reasons, the right brachial artery is commonly chosen; however, the left brachial artery may be preferable when pursuing access to the left vertebral artery.

1. 
   

   After the upper arm is prepared and draped, using a combination of palpation and ultrasound examination, the brachial artery pulse is identified. Ideally, the entry needle should gain access above the biceps tendon, avoiding the median nerve. Ultrasound is useful for avoiding puncture injuries to the median nerve, which can cause vessel injury. Once the puncture site has been selected, a local anesthetic is infiltrated ( Video 3.1 ).

   
   
2. 
   

   Using a microneedle (i.e., 21-gauge micropuncture kit), a single wall arterial puncture of the brachial artery is performed at a 45° angle with the bevel facing up.

   
   
3. 
   

   Once the return of brisk, pulsatile, bright red blood is established through the micropuncture needle, a 0.010-inch microwire is advanced through the needle. If resistance is noted, the practitioner should stop and redirect the needle. Once the wire has been advanced several centimeters, a fluoroscope is used to confirm the location of the wire. The needle is removed, and an intermediate 4–5 French (F) marker sheath dilator is inserted. The introducer that comes with the sheath dilator is then removed, and a J-tipped wire is inserted through the sheath. The sheath is then exchanged for the procedural sheath of choice. For diagnostic procedures, typically a 5F sheath is chosen; however, the brachial artery can support up to a 9F sheath for intervention. The insertion of larger sheaths (8–9F) often requires the use of an intermediate dilator and a longer, stiffer wire to upsize to the final sheath size ( Fig. 3.1 and Video 3.1 ).

   
   
4. 
   

   After arterial access has been established and before proceeding with the case, we routinely perform a brachial artery angiographic run. We assess brachial artery patency, stenosis, dissection, and possible extravasation ( Video 3.1 ).