Bill Johnson, Albuquerque, NM

	On the subject of vein mapping, I would appreciate comments about
mapping the internal mammary artery for coronary bypass.  We infrequently are
asked to do this, and, after bilateral brachial blood pressures, we scan the
subclavians and the IMA.  I am uncomfortable in that I have no criteria for an
"abnormal" test.   Following the IMA is sorta like following the vertebral in
the opposite direction, with rib shadows instead of vertebral processes.  We
have documented subclavian stenosis, and this impacted vessel selection, but
have not found anything in the IMA itself yet.  Anyone have experience/criteria
for this exam?  Is it justified?
	Also, as a comment, we have seen an increase in requests from
Cardio-Thoracic Surgery to evaluate radial arteries for bypass harvest, usually
on repeat CABGs who have had multiple vein harvests.  We image the subclavians,
brachial, radial and ulnar arteries and do a Doppler Allen's test.  Pretty much
our upper extremity arterial imaging protocol.