Misconceptions regarding the adequacy of best medical intervention alone for asymptomatic carotid stenosis
Anne L Abbott1, Alejandro M Brunser2, Athanasios Giannoukas3
1Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia.
Insights
Optimal medical intervention alone is sufficient for most patients with asymptomatic carotid stenosis (ACS). Additional procedures like carotid endarterectomy (CEA) or stenting (CAS) offer limited benefit and lack evidence for risk stratification.
Area of Science:
- Vascular Surgery
- Neurology
- Cardiology
Background:
- Medical intervention for stroke prevention has advanced significantly.
- Few individuals with advanced asymptomatic carotid stenosis (ACS) benefit from carotid procedures.
- The efficacy of medical intervention alone versus procedural intervention for ACS is debated.
Purpose of the Study:
- To examine the scientific validity of using stroke risk markers to guide carotid endarterectomy (CEA) or angioplasty/stenting (CAS) in patients with ACS.
- To evaluate the evidence for medical intervention alone versus combined medical and procedural intervention for ACS.
Main Methods:
- Systematic review of randomized trials comparing medical intervention alone with CEA or CAS for ACS.
- Review of evidence for stroke risk markers in selecting patients for CEA or CAS.
- Analysis of European Society for Vascular Surgery guidelines (2017) on risk markers.
Main Results:
- CEA provides a stroke prevention benefit for ACS only in select high-risk men (e.g., <75-80 years, ≥60% stenosis) based on older criteria.
- Current stroke rates with optimal medical intervention alone are lower than historical rates with CEA or CAS in trials.
- Trials comparing CEA and CAS are underpowered, with a trend towards higher stroke/death rates with CAS.
- Commonly cited stroke risk markers lack specificity and have not been validated with current optimal medical intervention for selecting patients for procedures.
Conclusions:
- Medical intervention is the established standard for managing ACS.
- Further research is needed on stroke risk stratification using current optimal medical intervention to identify candidates for additional carotid procedures.
Background:
Medical intervention (risk factor identification, lifestyle coaching, and medication) for stroke prevention has improved significantly. It is likely that no more than 5.5% of persons with advanced asymptomatic carotid stenosis (ACS) will now benefit from a carotid procedure during their lifetime. However, some question the adequacy of medical intervention alone for such persons and propose using markers of high stroke risk to intervene with carotid endarterectomy (CEA) and/or carotid angioplasty/stenting (CAS). Our aim was to examine the scientific validity and implications of this proposal.
Methods:
We reviewed the evidence for using medical intervention alone or with additional CEA or CAS in persons with ACS. We also reviewed the evidence regarding the validity of using commonly cited makers of high stroke risk to select such persons for CEA or CAS, including markers proposed by the European Society for Vascular Surgery in 2017.
Results:
Randomized trials of medical intervention alone versus additional CEA showed a definite statistically significant CEA stroke prevention benefit for ACS only for selected average surgical risk men aged less than 75 to 80 years with 60% or greater stenosis using the North American Symptomatic Carotid Endarterectomy Trial criteria. However, the most recent measurements of stroke rate with ACS using medical intervention alone are overall lower than for those who had CEA or CAS in randomized trials. Randomized trials of CEA versus CAS in persons with ACS were underpowered. However, the trend was for higher stroke and death rates with CAS. There are no randomized trial results related to comparing current optimal medical intervention with CEA or CAS. Commonly cited markers of high stroke risk in relation to ACS lack specificity, have not been assessed in conjunction with current optimal medical intervention, and have not been shown in randomized trials to identify those who benefit from a carotid procedure in addition to current optimal medical intervention.
Conclusions:
Medical intervention has an established role in the current routine management of persons with ACS. Stroke risk stratification studies using current optimal medical intervention alone are the highest research priority for identifying persons likely to benefit from adding a carotid procedure.
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