The problem with studies like these is that they're done on a mass basis; that is, they tell you what happens when you look at a mass of people, and compare outcomes. But a heart attack doesn't happen on a mass of people -- it happens on one person, and the idiosyncrasies of any particular case overwhelm indications from a mass study. Looked at as a mass, there may be no significant difference in outcomes between treatment with drugs, and treatment with stents. In one particular case, there may be huge differences -- a stent can prop open a clogged artery *right now* while drugs may take a course of treatment, and if you need the help right now, then there is a huge difference for you, even if it's not even a blip in a study.
I honestly think that many of these studies are driven by two things: costs, and warring cliques of doctors. If you can show there is a significant drop in costs with drugs, rather than surgery, then the government and insurance agencies will be pushing hard for drugs, and that will have an effect on treatments. And while costs may drop, in any particular case, you may have a death that wouldn't have happened if the other course were taken. One death among thousands of treatments may not be significant. But you're not a statistic; you're a human being. You're concerned with one particular outcome, while a mass study isn't.
And, of course, these studies have a direct impact on how mass treatments are done, driving patients one way or another, and thus effect medical incomes. Even doctors like money. I am aware of at least one such medical war (between board certified plastic surgeons and "cosmetic surgeons.") There are probably others, and the drugs/surgery case may well be one of them.
I have two stents in my heart, and don't regret them one bit. I had a heart attack in 2007 that was so mild that by the time I got to the hospital, they did an EKG and said I hadn't had a heart attack. Then they found some kind of chemical dude [dude=I don't know what it was] that is only produced by a heart attack, so yeah, I had one, but there was no detectable damage. The docs did an angiogram and found material narrowing in two heart arteries, and placed stents to prop the arteries open. No trouble at all the last 12 years and I work out hard. I do think things like personal habits are significant: if you don't smoke, drink very little, watch your diet, get some exercise, you'll probably stretch things out as long as is possible. Which is all you can ask for, IMHO.