Craig Walker, Cardiovascular Institute of the South, Houma, Louisiana.

Subclavian artery stenting is well established in the therapy of subclavian artery stenosis resulting in �subclavian steal,� arm claudication, myocardial ischemia in patients with prior or intended coronary artery bypass utilizing the internal mammary artery, and in patients with leg ischemia who have undergone axillofemoral bypass. The single-center experience published in the current issue of the Journal by Yu and colleagues10 describes their experience utilizing the transradial approach in the treatment of symptomatic subclavian artery lesions.

The transradial approach is increasingly being utilized in diagnostic and interventional procedures throughout the vascular system, as bleeding complications are nonexistent and patients can ambulate immediately. This approach can be utilized in fully anticoagulated patients without reversal of anticoagulation or antiplatelet drugs. It can be utilized safely where there is extensive lower-extremity atherosclerotic disease or in cases where there are abdominal aortic aneurysms with risk of peripheral embolization. As compared to the femoral approach in subclavian and upper-extremity intervention, the radial approach provides better support and avoids manipulation of catheters in the aortic arch and the potential danger of catheter injury of the origins of the great vessels that is inherent with a transfemoral approach. The brachial approach is limited in subclavian artery stenoses by potential bleeding complications, weak pulse and vessel mobility, making access difficult. Limitations of the radial approach include: 1) there must be a patent radial artery; 2) there must be a patent ulnar artery with evidence of adequate blood supply to the hand evaluated by the AllenâÂ?Â?s test (Figure 1), as there is up to a 2% risk of radial artery occlusion following transradial access; 3) visualization of the origin of the great vessels at stent implantation may be difficult (injecting against blood flow typically via small sheaths; and 4) occasionally, vascular spasm may occur. If visualization is an issue, a 4 Fr femoral catheter can be placed in the aortic arch to allow appropriate visualization for optimal stent deployment. Whereas many occlusions are more easily crossed in retrograde fashion via the radial artery, occasionally when retrograde crossing is unsuccessful, then crossing can be performed antegrade via the femoral approach utilizing catheters or wires placed via the radial approach as markers to aid guidewire crossing.

As with any approach, operator training and experience is paramount in utilizing the transradial approach in any diagnostic or interventional procedure. With appropriate training the transradial approach can clearly decrease access-site bleeding complications and may increase the rate of successful crossing of subclavian occlusions by providing better support thereby enhancing crossing success or by marking the subclavian artery for facilitating crossing via femoral approach. To avoid ischemic complications of this approach it is mandatory that assessment of collateral flow via a patent ulnar artery be evaluated prior to the procedure.

J Invasive Cardiol 2010 May; 22(5):207-8.