Appropriate management of asymptomatic carotid stenosis

Abstract

With modern intensive medical therapy, the annual risk of ipsilateral stroke in patients with asymptomatic carotid stenosis (ACS) is now down to ∼0.5%. Despite this, there is a widespread practice of routine intervention in ACS with carotid endarterectomy (CEA) and stenting (CAS). This is being justified on the basis of much higher risks with medical therapy in trials conducted decades ago, compared with lower risks of intervention in recent trials with no medical arm. Such extrapolations are invalid. Although recent trials have shown that after subtracting periprocedural risks the outcomes with CEA and CAS are now comparable to medical therapy, the periprocedural risks still far outweigh the risks with medical therapy. In the asymptomatic carotid trial (ACT) 1 trial, the 30-day risk of stroke or death was 2.9% with CAS and 1.7% with CEA. In the CREST trial, the 30-day risk of stroke or death among asymptomatic patients was 2.5% for stenting and 1.4% for endarterectomy. Thus, intensive medical therapy is much safer than either CAS or CEA. The only patients with ACS who should receive intervention are those who can be identified as being at high risk. The best validated method is transcranial Doppler embolus detection. Other approaches in development for identifying vulnerable plaques include intraplaque haemorrhage on MRI, ulceration and plaque lucency on ultrasound, and plaque inflammation on positron emission tomography/CT. Intensive medical therapy for ACS includes smoking cessation, a Mediterranean diet, effective blood pressure control, antiplatelet therapy, intensive lipid-lowering therapy and treatment with B vitamins (with methylcobalamin instead of cyanocobalamin), particularly in patients with metabolic B12 deficiency. A new strategy called ‘treating arteries instead of risk factors’, based on measurement of carotid plaque volume, is promising but requires validation in randomised trials.

Recent Update on Carotid Endarterectomy versus Carotid Artery Stenting

“…However, evidence to date [39,40] has shown that natural history of asymptomatic CS has improved significantly with modern BMT, and routinely treating asymptomatic patients with CR, considered by degree of stenosis, is not reliable. Annual stroke risk of CR was similar to modern BMT while there were periprocedural risks in CR but not in BMT.…”

“…Annual stroke risk of CR was similar to modern BMT while there were periprocedural risks in CR but not in BMT. Therefore, selection of asymptomatic patients based on their respective 'high-risk features' ( table 4 ) for CR would be reasonable and beneficial to prevent stroke [23,39,41,42] .…”

Symptomatic vs. Asymptomatic 20–40% Internal Carotid Artery Stenosis: Does the Plaque Size Matter?

“…However, these data should be interpreted with caution, because they were conducted before the introduction of optimized medical treatment. The latter includes antiplatelets, statins, control of blood pressure and blood glucose level, smoking cessation, implementation of exercise programs, Mediterranean diet, and lifestyle modification, and was shown to significantly reduce the stroke risk among patients with asymptomatic ICA-stenosis (30, 31). Current optimized medical treatment is an established therapy for prevention of arterial disease complications, including patients with carotid stenosis, whether mild or severe, and it is a continually improving gold standard of care (32, 33), and should also be offered perioperatively before CEA (34).…”

The parameters of carotid plaques’ calcifications and clinical nature of the lesions in the context of revascularization treatment. The enlargement of calcifications is still the most important

“…Carotid artery revascularization in patients with asymptomatic stenosis raises consider-able doubts, which stems from the low estimated risk of stroke related to asymptomatic lesions. This risk is often believed not to exceed the risk of stroke associated with revascularization therapy alone [8,18,22,31,32].…”