Near-Occlusion of Left Vertebral Artery & Looking For Advice

I'm 73, female, on Eliquis & had an unusual headache for 5 days, so my PCP recommended a brain CT scan with contrast to rule out a bleed & gratefully none was found, but a near-occlusion of my left vertebral artery was found. Radiology report indicated the cause as either plaque or dissection. ER doc thinks the headache was unrelated to that finding and I'm asymptomatic thus far. My PCP is mulling over whether or not I should take aspirin and wants me on a statin (even tho I'm intolerant/myalgia).

This is all brand new to me and I have no idea how serious this is...the ER doc said I could have a stroke in 5 years. What is the best treatment for this condition and have any of you successfully prevented the near-occlusion from worsening?

Thanks, in advance, for any guidance or opinions.