Who's Responsible?

So here's the latest on stents and heart bypass surgery. It's been 2 and a half years since Kevin's heart attack and I still second guess myself. Why didn't we question the doctor more, why didn't they tell us one of the stents was planned for the artery known as "the widowmaker," why didn't they know then that someone with the blockage Kevin had should have been a candidate for surgery right away? Why couldn't they have figured this out three years BEFORE Kevin's heart attack? And I know all the answers - he was 44, in good health, no history in his family. So my head knows we did the best we could. Just wish I could feel it.