Clinical usefulness of carotid ultrasound to improve stroke risk assessment: ten-year results from the Carotid Atherosclerosis Progression Study (CAPS).
Level 3 - non-randomized controlled study
Prospective cohort follow-up study evaluating a prognostic risk prediction tool.
PubMed 22617119 · doi:10.1177/2047487312449589
What was done
Researchers evaluated 4,995 asymptomatic participants from the Carotid Atherosclerosis Progression Study (CAPS) followed for 10 years. Baseline assessments included conventional risk factors and carotid ultrasound measuring intima-media thickness (IMT) and plaque across carotid segments. Using reclassification metrics across four risk categories, the authors evaluated whether adding ultrasound parameters improved stroke prediction over the standard Framingham Stroke Risk Score (FSRS).
What was found
Carotid ultrasound did not improve most risk models. Intima-media thickness or plaque in the internal carotid artery provided more prognostic utility than common carotid or bifurcation IMT. For the composite outcome of 'any stroke or death', adding ultrasound significantly improved prediction: 339 participants (7.2%) were reclassified (122 to a higher risk category, 217 to a lower category), with 182 (53.7%) classified correctly. The net reclassification improvement (NRI) was 7.7% (p = 0.029) and the integrated discrimination improvement (IDI) was 0.73% (p = 0.023).
Why it matters
Routine carotid ultrasound screening has questionable utility for stroke prediction alone, but imaging internal carotid segments may modestly refine risk stratification when evaluating combined mortality and stroke risk.
Limits
The abstract notes that most stroke-specific prediction models showed no significant improvement with ultrasound. The positive reclassification was limited to a composite endpoint of stroke and all-cause death. Specific demographic details, baseline medication usage, and loss to follow-up rates are not reported in the abstract.
Cited by
- context The CAFE and CAPS studies demonstrated that CIMT (carotid intima-media thickness) predicts the risk of heart attack and stroke through soft plaque.