How do we treat asymptomatic carotid artery stenosis?
In medical school, I learned about the seminal trials that showed the benefit of carotid endarterectomies for lesions above 70%, even in asymptomatic patients. And indeed, years later, the 2011 AHA/ACC guidelines on carotid artery disease give a IIa recommendation for endarterectomy for asymptomatic stenosis above 70%, and IIb for stenting for asymptomatic stenosis (70% on ultrasound, 60% on angiography). They also say we should not intervene for lesions less than 50% - class III – and acknowledge that there is limited data about medical management for this disease process.
In doing this literature search, I have to say, there’s not a good answer to this question. We know that intervening for carotid artery stenosis is generally safe. Rates of adverse events after revascularization in asymptomatic patients are low: 0.7-0.8% death, 1.6-3.9% stroke, and 0.8-1.2% MI (note some studies quote a mortality rate as high as 3%, raising the issue of patient selection). Both the CREST and ACT-1 trials found stenting and endarterectomy to be reasonably comparable to each other in terms of endpoints: the former with more MI, the latter with more stroke, but no difference in long-term outcomes. Check out the attached JACC review for a nice summary of where we are now, including some details about anatomic considerations and reimbursements which some of you may find useful.
But the question of whether we should even intervene remains unanswered, at least with good data. To that end, I enjoyed reading the attached commentary from Neurology from a few years ago; it’s a nice recap of recent history and what remains unknown around these lesions. We also don’t know among our medical therapy options – namely aspirin, clopidogrel, and aspirin/dipyridamole – which is best. I will eagerly be awaiting the CREST-2 trial, which is recruiting now, and which seeks to compare medical therapy to revascularization in the modern age.
Based on what I read, I feel comfortable working on optimal medical therapy for this patient and deferring a vascular surgery referral for now. Please let me know if you have further insights!
Beckman JA, Ansel GM, Lyden SP, Das TS. Carotid Artery Stenting in Asymptomatic Carotid Artery Stenosis. Journal of the American College of Cardiology. 2020;75(6):648-656. doi:https://doi.org/10.1016/j.jacc.2019.11.054
Brott TG, Halperin JL, Abbara S, et al. 2011 Guideline on the Management of Patients With Extracranial Carotid and Vertebral Artery Disease. Journal of the American College of Cardiology. 2011;57(8):e16-e94.
Heck DV, Roubin GS, Rosenfield KG, et al. Asymptomatic carotid stenosis. Neurology. 2017;88(21):2061-2065. doi:https://doi.org/10.1212/wnl.0000000000003956
