Need some advise 64Y/M with Diabetes

I failed a stress test with a positive for inducible ischaemia at low work load and was advised to take an angiograph. The results are as follows:

- 70% stenosis at the ostium of the LAD and 70% stenosis after D1 (D1 is fair sized normal vessel)
- 90% stenosis in proximal segment of the Ramus Intermedius
- 50% stenosis in OM1 a small sized vessel in Circumflex
- 30% stenosis in proximal segment of RCA followed by 70% before RV branch.

I had gone in thinking the worst case scenario would be getting stents but it seems the Cardio says with the number of blockages the best option is to go for CABG.

A little medical background
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I have type II diabetes and have been treating it with medication and also have hypertension. I have managed to control these to some extent without having to take insulin shots.

My Cholestrol at last check was 210
HDL at 54.6
LDL at 132,
Trigylcerides 117

I am a pure vegetarian, have never smoked or drink alchohol. My BMI is 20.8 which is normal for my height (180cms / 67kg). I exercise every day and haven't really had a sign of any heart problems and were it not for the stress test I would not be considering the CABG which the cardio has suggested.

At present I'm left in a state of shock as to whether to undergo a serious invasive surgery given none of the symptoms of CAD have manifested, or do i trust the doctor and to the procedure and then face the chances of some complications.