Sentence:  Tiny metal sleeves placed in arteries to keep blood flowing, <WSD>stents</WSD> have become such a popular quick fix for clogged coronary vessels that Americans will receive more than 1.5 million of them this year. 
Meaning of the word marked with <WSD> tags:  A slender tube inserted into a blood vessel, a ureter or the oesophagus in order to provide support and to prevent disease-induced closure.