Submitted by Dr T on March 27, 2011 – 7:14am
He may have a condition called Coarctation, which can be diagnosed with a CT scan or MRA. Although a bit complicated, I wrote this article for medical students that may help explain this condition. It is a congenital narrowing of the aorta between the arteries to right and left arms causing the differences in blood pressure. Of course, it could just be an error doing the blood pressure test, but if true it may require treatment, most often an operation to remove the obstruction.
Hope this helps,