Implantation of stents--mesh cylinders that widen clogged arteries--is growing so fast that some doctors say the procedure is overused. Yet the inserts have been evolving for 20 years, proponents note, and represent an alternative to more invasive open surgery.
For decades, coronary patients whose arteries had been narrowed by accumulated plaque underwent open-heart surgery; a section of healthy artery or vein was sewn in as a bypass around the compromised vessel. Similar measures were taken with patients who had blocked arteries elsewhere, or the artery was cut open and the plaque scraped out. The advent of balloon angioplasty reduced the intrusiveness for certain patients; a balloon was fed along a catheter to the blockage, then expanded to crack and compress the plaque, leaving a wider conduit for blood flow. Yet arteries often renarrowed if walls recoiled or if fibrous tissue grew.