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Outcome of patients with symptomless carotid bruits: a prospective study
Insights
Symptomless carotid artery disease progression was studied in 336 patients. Carotid endarterectomy improved outcomes for high-grade stenosis, reducing transient ischemic attacks (TIAs) and stroke risk.
Area of Science:
- Vascular Surgery
- Neurology
- Cardiovascular Disease
Background:
- Understanding the natural history of asymptomatic carotid artery disease is crucial for effective preventative strategies in patients without symptoms.
- Carotid artery stenosis is a significant risk factor for cerebrovascular events, including transient ischemic attacks (TIAs) and stroke.
Purpose of the Study:
- To document the natural progression of carotid artery disease in a symptomless population.
- To evaluate the clinical outcomes and event rates associated with asymptomatic carotid artery stenosis.
- To assess the effectiveness of carotid endarterectomy in preventing cerebrovascular events in high-grade stenosis.
Main Methods:
- Prospective follow-up of 336 patients with asymptomatic carotid bruits using oculoplethysmography and duplex scanning.
- Analysis of annual event rates for stroke, TIA, and cumulative ischemic events.
- Comparison of outcomes between operated and non-operated arteries in a subgroup with high-grade stenosis (80-99%).
- Review of serial duplex studies to assess disease progression and correlation with symptomatic events.
Main Results:
- Over a mean follow-up of 4.87 years, 2.4% of patients suffered a stroke and 11.0% experienced TIAs, with a cumulative event rate of 13.4%.
- In high-grade stenosis (80-99%), the 5-year event rate was significantly lower in operated arteries (6.4%) compared to non-operated arteries (51.0%).
- Disease progression was observed in 29.3% of carotid arteries, and symptomatic events occurred without significant diameter change in 65.9% of cases.
- Patients with internal carotid artery stenosis exceeding 80% had higher incidences of TIA, stroke, and death compared to those with less severe stenosis.
Conclusions:
- Asymptomatic carotid artery disease carries a significant risk of cerebrovascular events, with higher risks associated with high-grade internal carotid artery stenosis.
- Carotid endarterectomy appears to improve neurological status and reduce the risk of TIA and stroke in patients with symptomless high-grade carotid artery stenosis.
- While endarterectomy improved event rates, overall mortality was not significantly different between operated and non-operated groups.
Abstract:
Knowledge of the natural history of symptomless carotid artery disease is important in determining the best preventative treatment for symptom-free patients. To document the progression of carotid artery disease and the clinical course of a symptomless population, 336 patients with symptom-free carotid bruits were prospectively followed up initially with oculoplethysmography and subsequently with duplex scanning. During a mean follow-up of 4.87 years, eight patients (2.4%) suffered a stroke. Thirty-seven (11.0%) experienced transient ischaemic attacks (TIAS). The cumulative event rate (TIA plus stroke) was 13.4% (45/336). The annual event rates were 0.48% for stroke, 2.26% for TIA and 2.75% for all ischaemic events. In a subgroup of 69 high-grade carotid stenoses (80-99%), 31 carotid endarterectomies were performed before the development of a TIA or stroke and 21 after the development of symptoms, while 17 lesions were followed-up non-operatively. The total event rate (TIA and stroke) was significantly greater in the non-operated compared with the operated arteries (51.0% versus 6.4% at 5 years, P=0.0034). However, most of the events which occurred in the non-operated group were TIAs (85.7%) rather than stroke. There was no difference In the death rate of the two groups (P>0.05). Review of serial duplex studies performed on 540 carotid arteries revealed that 382 arteries (70.7%) remained unchanged and 158 (29.3%) showed disease progression. Forty-four of the 540 arteries became symptomatic (TIA or stroke). In 29 of the 44, the event occurred without any change in diameter of the artery, while in 15 there was a change of at least one category greater stenosis. In 39 patients, the stenosis was at least 40% and in five the stenosis was under 40%. Nine events occurred in the patients with severe contralateral carotid stenoses (>60%). The incidence of TIA (32.2%), stroke (6.8%) and death (18.6%) was higher in patients with internal carotid artery stenoses in excess of 80% than in those with lesions between 0 and 79% stenosis (P<0.0001, P= 0.0367 and P=0.0236, respectively). In this study the incidence of cerebrovascular events was higher in patients with high-grade internal carotid artery disease, and the preservation of neurological status in patients with symptomless high-grade carotid artery stenosis was improved by carotid endarterectomy, although the overall mortality remained unchanged.