Cartoot,
Thanks for the post.
Yes, many
blockagesPeripheral artery disease serve as sites for spasm. So a fixed obstruction of 50% can become 90% when the artery develops spasm in that area. Nitroglycerin often relieves spasm, but not the fixed blockages, thus after getting the nitroglycerin your obstruction went from 90% to 45%.
Hope that helps.