I have a fully blocked LAD. A well known interventional cardiologist could not open it. I have collaterals and a right coronary artery that has extended itself to the left side of my heart. I regret the effort to open it, it caused me pain, months of slowly exercising to recover. I have a strong, regular heartbeat and should never have tried to have it opened.
Yes 100% blockages can certainly be treated with stents, I am walking proof. My LAD was 100% blocked with very hard plaque which had to be slowly chipped away, and the blockage was on a curve. However, to do this, you would require a Cardiologist with a LOT of experience.