The History of Angioplasty, Heart Catheterization, and Heart StentsDr. Christopher Nielsen: Just to go through the history of Heart Catheterization, and Balloon Angioplasty, and Stents. The first thing that came about was just Balloon Angioplasty, and that was to push the plaque out of the way, that was a great advance, because before that all you could do was open heart surgery. So somebody figured out that you could just push the plaque out of the way that was great, it worked great. However, about 40% or 50% of the time that would narrow down again over the course of a few months.So somebody figured out that if we make a metal mesh tube that holds the plaque out of the way, that would be even better, and sure enough it was. But it came with about 10% of people would end up, building up scar tissue inside that stent, because it's a foreign body that's inside the body.Sometimes the body will make scar tissue in there, and that stent will fill up with plaque and scar tissue, and block up again. So that's was about 10%, that was a lot better than the Balloon Angioplasty, but it wasn't perfect yet. So then people came up with the idea of placing special drugs on that stent, and those drugs would prevent any scar tissue or plaque from forming in there.Those first became available several years ago, and now there are three different stents with three different drugs on the market, and a forth one getting ready to be released very soon. And they worked really well, and they take it down to just a few percent less than 5% of people that end up building up any plaque, and having to come back in a few months