It depends on many things for a stent being possible. Firstly, if the occlusion is hard, as in solid plaque, it can be impossible to get a catheter wire through it to the other side. This would involve 'chipping' away at it producing a risk of losing pieces of plaque to lodge in small vessels in the heart or brain. If the occlusion is on a curve this can also be a much higher risk because as the catheter goes through the occlusion it can end up through the artery wall on the other side.
The occlusion I had removed at the top of my LAD was 30mm long and the first 10mm was solid plaque. The occlusion was on a curve and the start was right on the very edge of the circumflex branch. It took 5 stents to clean up the artery and I think the cardiologist performed a small miracle. I saw 12 other cardiologists and they all said it was either impossible or too risky. Finding a very confident cardiologist due to experience can be difficult. My cardiologist has been doing stenting for over 20 years now and is seen in the UK as the stent king.
To stent in a multi-vessels on the same vessel can change the hemodynamics of the vessel segment involved and affect blood flow to other areas. A by-pass may bridge more than one lesion, and there will be a different dynamic and possibly a more favorable expectation.
There is a need to assess whether there may be a surgical problem for surgery based on weight and diabetes could be another consideration and there can be a problem with healing for diabetics.