In this episode we delve into the interesting world of carotid artery disease and discuss our management of patients who are asymptomatic. See Yogi's (amazing) crib notes below:

Why do we care about asymptomatic carotid artery disease?

• About 10 to 15% of all first ever stroke patients will experience an unheralded ischaemic, carotid territory stroke following thromboembolism from a previously untreated asymptomatic significant carotid disease

Oxford Vascular Study

• Enrolled 2354 consecutive patients including 207 with 50 to 99% carotid stenosis
• The ipsilateral stroke rate at 5 years for the patients with 70% to 99% was 14.6% compared with 0% for 50 to < 70%
• For patients with 80 to 99% carotid stenosis, the ipsilateral stroke was significantly greater than that for those with 50% to <80% stenosis

 ACSRS Study

• In ACAS and risk of stroke, there was an S-shaped relationship between the severity of stenosis and the incidence of ipsilateral TIA or stroke, such that the event rate for 50 to 69% stenosis were 8.2%, for 70 to 89% were 10.7% and for 90 to 99% were 19.3%
• Progression of carotid stenosis is associated with an increased risk of stroke - patients with progression of carotid stenosis had two times the rate of ipsilateral stroke compared to patients without progression

Prevalence of ACAS

• Four Population Based Cohort Studies (Malmo Diet and Cancer Study, Tromso Study, Carotid Atherosclerosis Progression Study and Cardiovascular Health Study)
• Prevalence of asymptomatic moderate (>50%) and severe (>70%) stenoses in a population of 23,706 people (mean age of 61 years, 46% male) was 2.0% and 0.5% respectively
• Moderate stenosis > 50% found in 4.8% of men and 2.2% of women younger than 70 years
• The percentage increase to 12.5% in men and 6.9% in women if patients older than 70 years are considered

Severe asymptomatic stenosis (>70%) indicate that its prevalence ranges from 0% to 3.1% of general population

Seminal Trials

Seminal trials have demonstrated a marginal but definitive benefit for CEA in reducing the risk of stroke after 5 and 10 years when compared with “best medical therapy” alone. However, these studies conducted in the late 1980s and in the 1990s, and since their completion, progress in the medical management of cardiovascular diseases has led to a progressive decrease in the yearly risk of stroke in patients with asymptomatic carotid artery stenosis managed with medical treatment alone.

Veterans Affairs Cooperative Study (VACS) [1983 and 1987]

• 440 men with asymptomatic >50% carotid stenosis were randomised to CEA plus medical management versus medical management only CEA significantly reduced the combined incidence of ipsilateral neurologic events (stroke or TIA) compared to medical group (8.0% vs. 20.6% respectively)

ACAS

• 1662 patients with asymptomatic >60% carotid stenosis were randomised to medical therapy versus CEA plus medical therapy
• Across the United States and Canada
• The study was stopped early, after a median follow up of 2.7 years
• Patients in the surgical arm had a 5.1% risk of ipsilateral stroke and preoperative stroke/death over 5 years versus 11.0% risk of ipsilateral stroke in the medical arm for a relative risk reduction of 53%; absolute risk reduction of 5.9%
• Recommended CEA for patients aged < 80 years as long as the expected combined stroke and mortality rate for the individual surgeon as not > 3%

 ACST-1

• 3120 patients with asymptomatic >60% carotid stenosis were randomised to either immediate CEA or deferred