Hebrew to English Medical Medical: Cardiology Stents

This is in a section dealing with angiographic inclusion criteria for a clinical trial. I have never come across this term and can't find any instance of it on the net. The only thing I can think of is that it is somehow intended to distinguish between an artery that has had a stent implanted and an "original one" but I'm not willing to guess.
For slightly more context:
היצרויות המטרה צריכות להיות ממוקמות בעורק כלילי מולד עם קוטר הגדול או שווה ...