My Vascular Surgeon Said My Left Carotid Arterty Is 85%

My vascular surgeon said my left carotid arterty is 85% blocked, based on an ICA of 266, an ICA/CCA ratio of 2.5, and an CT scan, and recommended surgery. Using the same data, my former vascular surgeon (in another county) said 50-69% blockage, and no surgery. A third vascular surgeon said he is okay with an ICA of 280 before recommending surgery. I believe the NASCET criteria is 4.0 for the ratio. Also, i recently read a study done in 2020 that concluded that asymptomatic patients should not have surgery because of the risks. How do I assess my risk?