The final publication of midterm results from the observational CARAS study suggest that cerebral ischaemic event (CIE) incidence in asymptomatic carotid stenosis patients “should not be underestimated”, so say authors Rodolfo Pini (University of Bologna, Italy) and colleagues, relaying these findings in the Journal of Stroke and Cerebrovascular Diseases.
The authors further conclude that plaque progression and contralateral stenosis are among factors that may serve as primary predictors of CIEs, as per the results of their midterm analyses—which were initially presented at last year’s Vascular Annual Meeting (VAM; 14–17 June 2023, National Harbor, USA).
“Carotid endarterectomy [CEA] in patients with asymptomatic carotid stenosis remains a subject of debate,” Pini and colleagues initially state. “Current recommendations are based on randomised trials conducted over 20 years ago and improvements in medical therapies may have reduced the risk of CIEs. This study presents a midterm analysis of results from an ongoing, prospective, observational study of [asymptomatic carotid stenosis] patients to assess their CIE risk in a real-world setting.”
CARAS is a prospective, observational study of a cohort of asymptomatic patients with >60% carotid stenosis—as per criteria from the original NASCET trial—identified in a single duplex ultrasonography vascular laboratory. Short life expectancy and absence of signs of plaque vulnerability are among the factors cited by the authors for patients in the study not being considered for CEA.
The study’s primary endpoint is to assess CIEs ipsilateral to asymptomatic carotid stenosis, including strokes, transient ischaemic attacks (TIAs), and amaurosis-fugax, along with plaque progression rate and patient survival.
Patient enrolment took place from January 2019 to March 2020, with a sample size of 300 patients being targeted and a five-year follow-up scheduled. CARAS ultimately included a total of 307 patients (average age, 80 years; 55% male), of whom 61 (20%) had contralateral stenosis >60% and some 77% were on best medical management.
At a mean follow-up of 41 months, seven ipsilateral strokes and nine TIAs occurred, resulting in a total of 14 CIEs, Pini and colleagues report. They also note that two patients experienced both stroke and TIA during the follow-up period. And, as per a Kaplan-Meier analysis, the four-year CIE rate was 6%, with an annual CIE rate of 1.5%.
Disclosing further detail on their midterm results, the authors relay that 58 patients (19%) had a stenosis progression that was associated with a higher four-year estimated CIE rate compared to patients with stable plaque (10.3% vs. 3.2%, p=0.01). Similarly, contralateral carotid stenosis >60% was associated with a higher four-year estimated CIE rate (11.7% vs. 2.9%, p=0.002). A multivariate cox analysis revealed that these factors were independently associated with a high CIE risk, with hazard ratios of 3.2 and 3.6, respectively.
“The midterm results of this prospective study suggest that the incidence of CIE in [asymptomatic carotid stenosis] patients should not be underestimated, with plaque progression and contralateral stenosis serving as primary predictors of CIEs,” Pini and colleagues conclude.
