Background
The radial artery access sheath is used to gain arterial access and facilitate the insertion of catheters or other equipment for diagnostic and vascular interventions. [1] Compared with procedures performed via the commonly used femoral artery access route, procedures performed via the radial artery route allow shorter recovery time, earlier ambulation, earlier discharge, and lower incidences of access-site complications, as well as being advantageous for patients with occlusive aortoiliac disease or peripheral vascular disease.
However, specific challenges exist in using radial artery sheath access. The radial artery is smaller than the femoral artery, and thus, more finesse and experience are required to access this vessel. In addition, a smaller sheath precludes the use of larger catheters and equipment, which may be needed for major operations. Finally, radial artery spasm is a risk, necessitating routine use of antispasmodic medications.
Indications
Indications for radial artery sheath insertion include the following:
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Coronary angiography and percutaneous coronary interventions
Contraindications
Absolute contraindications for radial artery sheath insertion include the following:
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Patients with an abnormal Allen test result
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Patients who require support devices such as an intra-aortic balloon pump (IABP) or other devices that are not compatible with sheaths smaller than 7 French
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Patients with known congenital or noncongenital vascular anomalies of the upper limb
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Patients with known upper-limb peripheral vaso-occlusive disease, including thromboangiitis obliterans (Buerger disease) and Raynaud disease
Relative contraindications for radial artery sheath insertion include the following:
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Patients with chronic renal failure who require consideration of an arteriovenous fistula in the upper limb
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Patients whose radial artery is being considered as a conduit for coronary artery bypass grafting (CABG)
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Patients requiring angiographic evaluation of internal mammary artery (IMA) grafts after CABG; in such cases, access may be obtained via the ipsilateral radial artery (ie, the left radial artery for a left IMA graft and the right for a right IMA graft) because the contralateral IMA is very difficult or impossible to access and carries an increased risk of vascular complications
Technical Considerations
Anatomy
Before attempting to insert a radial artery sheath, the operator should be familiar with the anatomy of the blood supply to the hand. The radial artery is a branch of the brachial artery, originating above the elbow. It passes down the forearm between the tendons of the brachioradialis and the flexor carpi radialis and winds around the lateral aspect of the radius. It then crosses the floor of the anatomic snuffbox to pass between the two heads of the first dorsal interosseous muscle to join the deep palmar arch.
The collateral circulation is supplied via the ulnar artery and should be assessed by performing the Allen test. This can be done either visually or with oximetry. An abnormal Allen test result is a contraindication for radial access.
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Basic setup for insertion of 6-Fr radial sheath.
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Radial artery sheath insertion. Shown are micropuncture needle (above) and cannula-over-needle (below).
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Radial artery sheath insertion. Shown are 5-Fr and 6-Fr radial access sheath with dilator inserted through sheath ready to be used.
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Radial artery sheath insertion. Wrist is positioned by using medical towel. Hyperextension splint may also be used.
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Radial artery sheath insertion. Palpate for radial artery at its expected course.
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Radial artery sheath insertion. Puncture radial artery using either micropuncture needle or cannula-over-needle assembly until flashback of arterial blood is observed.
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Radial artery sheath insertion. Insert guide wire through cannula/micropuncture needle. Once guide wire is sufficiently inserted, cannula/micropuncture needle is removed, leaving guide wire in place.
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Radial artery sheath insertion. Once radial sheath is sufficiently advanced, remove guide wire and dilator.
