Background and Aims:
We wanted to determine baseline cognition via telephone assessment among individuals in CREST-2 (clinicaltrials.gov NCT02089217), which enrolls cognitively competent individuals with asymptomatic carotid artery occlusive disease or remotely symptomatic atherosclerotic stenosis. Participants undergo baseline cognitive assessment before revascularization or starting medical management alone, and at periodic follow-up. To minimize assessment variability of cognition across >120 CREST-2 centers, we employ centrally-administered telephone assessments, based on the population-based REGARDS cohort study.
Data came from the first 1,000 patients . We used the REGARDS protocol of CERAD Word List Learning (WLL-Sum) and Delayed Recall (WLL-Delay), and Word Fluency for the letter “F” and Animal Names. Using the general population norms from REGARD (N>23,000), we calculated Z-scores for each CREST-2 test, based on the mean score for age-sex-education matched REGARDS participants.
The mean age was 69 yrs, 59%M, and 47% left-sided stenosis. Among our tests, the burden of impairment was found in WLL Learning (p<0.0001) and WLL-Delay (p<0.0001), with relatively little impact on Word Fluency measures. For WLL-Delay, the 50th and 25th percentiles in CREST-2 were at the 25th and 8th percentiles in REGARDS, respectively.
Patients with high-grade asymptomatic carotid stenosis had significantly lower baseline learning and memory scores than the general population. These data justify the use of a telephone-based test battery for testing cognitive change in CREST-2 and relevance for testing reversibility in the CREST-H (hemodynamics) subset with cerebral hypoperfusion.