Atherosclerosis in the arteries of the arm is less common than seen in the legs. Stenosis or occlusion of these arteries can cause ischemia in the hand and in worst cases can result in tissue loss. An embolus (blood clot) from a more proximal aneurysm or from the heart can suddenly occlude the arm arteries, with smaller blood clots being able to occlude the hand and finger arteries. Diabetes and renal disease can cause excessive calcification of the radial and ulnar arteries. Atherosclerosis is more likely to be seen in the arm arteries of diabetic and renal patients.
Occlusion or stenosis of the more proximal upper arm arteries can result in lower brachial artery blood pressure. Patients with uneven brachial blood pressure should be scanned for arterial disease. Occlusion or high grade stenosis of the proximal subclavian arteries can result in retrograde or reverse flow in the ipsilateral (same side) vertebral artery. This may cause neurological symptoms and should be assessed.
The radial artery is commonly harvested for coronary artery bypass surgery. Ultrasound assessment of the arm and palmar arch arteries before surgery can provide information about the adequacy of the collateral blood supply to the hand if the radial artery is harvested. The quality of the radial artery can be assessed before harvesting or before placement of a radiocephalic AVF to ensure the best outcome.
PATIENT PREPARATION AND EXAMINATION TECHNIQUE:
No special patient preparation required.
The patient will be examined either lying or sitting with the arm supported on a pillow. The subclavian, axillary, brachial, radial and ulnar arteries will be examined with B-mode and Doppler to assess artery patency and whether a stenosis is present. The site and degree of stenosis will be recorded. Aneurysmal dilatation of the arteries will be noted and size measured with the presence or absence of thrombus commented on. The presence of calcification will be commented on.
20 – 30 minutes.
Degree of stenosis in the arm arteries is classified as <50% stenosis (ratio of 1.5-2), >50% stenosis (ratio of 2-4), >75% stenosis (ratio of >4) and occlusion.