National Letter of Intent. The National Letter of Intent (NLI) is a document used to indicate a student athlete's commitment to participating National Collegiate Athletic Association (NCAA) colleges and universities in the United States.
Collateral Vessel Closure. Collateral vessels are abnormal blood vessels that connect the aorta with the pulmonary arteries. The aorta is a blood vessel that carries blood from the heart to arteries throughout the body.Pulmonary arteries are the vessels that transfer blood from the heart back to the lungs for oxygen.Everyone has collateral vessels, but they're normally small and not in use.They become enlarged in some people with congenital heart disease (heart disease that's present since birth).ulmonary arteries are the vessels that transfer blood from the heart back to the lungs for oxygen. Everyone has collateral vessels, but they're normally small and not in use. They become enlarged in some people with congenital heart disease (heart disease that's present since birth).
When an artery in the brain is blocked due to stroke or transient ischemic attack (TIA), open collateral vessels can (but not always) allow blood to detour around the blockage. This collateral circulation restores blood flow to the affected part of the brain.hen a collateral vessel on the heart enlarges, it lets blood flow from an open coronary artery to an adjacent one or further downstream on the same artery. In this way, collateral vessels grow and form a kind of detour around a blockage.