Review Article
Asymptomatic and Symptomatic Carotid Stenosis: An Obsolete Classification?
Table 1
Outline of the most important characteristics and results of large carotid surgery trials. DSA: digital substraction angiography.
| | NASCET | ECST | ACAS | ACST |
| | (total) | 2885 | 3024 | 1662 | 3120 | | Observation period prior to inclusion (max.) | 120 days | 180 days | 120 days | 180 days | | Ratio TIA/stroke as qualifying event prior to inclusion | 61%/39% | 50%/50% | — | — | | Diagnostic method for determination of stenosis grade (SG) | DSA (distal SG) | DSA (local SG) | Doppler sonography/DSA | Duplex sonography | | Significant correlation of stroke risk with SG | Yes | Yes | No | No | | Controlled medical treatment | No | No | No | No | | Indication for carotid surgery | Limited at 50–69% SG | >70–99% SG | Limited at 50–69% SG | >70–99% SG | No | Limited at >60–99% | | Stroke risk (surgical treatment) (%) | 15.7 (5 yrs) | 8.9 (3 yrs) | 15.0 (5 yrs) | 10.5 (5 yrs) | 5.1 (5 yrs) | 6.4 (5 yrs) | | Stroke risk (medical treatment) (%) | 22.2 (5 yrs) | 28.3 (3 yrs) | 12.1 (5 yrs) | 19.0 (5 yrs) | 11.0 (5 yrs) | 11.7 (5 yrs) | | Absolute risk reduction (%) | 6.5 | 19.4 | −2.9 | 8.5 | 5.9 | 5.4 | | Relative risk reduction (%) | 29 | 69 | — | 45 | 53 | 46 | | Numbers needed to treat | 15 | 5 | — | 12 | 17 | 19 |
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