Only a few dictionaries I consulted at a public library list "stent". Random House Unabridged, Second Edition, defines it as
Med. a small expendable tube used for inserting in a blocked vessel or other part [1960-65, orig. uncert.]I would have said "into" instead of "in", but more importantly, "expendable" seems to be simply an error. The point of a stent is that it can be inserted into a blood vessel in collapsed form, then expanded to hold open the filmsy walls of the vessel. The word should have been "expandable". [It is "expandable" in a 1999 printing of Random House Webster's College Dictionary. —TG]
My guess is that a dictionary editor who did not know what a stent is thought it must be a disposable, throwaway device that gets consumed (maybe gets dissolved in the bloodstream as its purpose is fulfilled) and is hence "expendable".
American Heritage Dictionary, Fourth Edition, gives two definitions of "stent", one for use in skin grafting, and one for use in keeping vessels and body cavities from collapsing, and gives the etymology as[After Charles A. Stent (1845-1901), English dentist].
(July 29, 2003)