Mid-term Results of the Carotid Asymptomatic Stenosis Observational Study

The present study analyzes the mid term results from an ongoing prospective observational study of patients with carotid asymptomatic stenosis (CARAS) to assess their risk of cerebral ischemic event (CIE) in a real-world scenario. This is a prospective observational cohort study of patients with CARAS >60% (North American Symptomatic Carotid Endarterectomy Trial criteria) identified in a single duplex ultrasonography vascular laboratory (trial registered: NCT04825080). Patients were not considered for carotid endartecetomy owing to their high surgical risk or advanced age (>80 year) or absence of signs of plaque vulnerability (ulceration, nonechogenicity). Patient enrollment started in January 2019 and ended in March 2020. The aimed sample size calculated was 300 patients for a 5-year period of follow-up. Clinical characteristics, risk factors and medical therapies were collected and best medical therapy (BMT: antiplatelet, pressure control and statins) was recommended if necessary at the first clinical visit. The primary end point was to evaluate CIEs (strokes, transient ischemic attacks, amaurosis fugax) ipsilateral to CARAS and assess plaque progression rate and patients survival. The follow-up is performed through a clinical visit and carotid duplex ultrasonography examination every year with telephone interviews at 6-month intervals. A total of 377 patients were enrolled in the study and 306 (81%) completed the follow-up. The mean age was 80 ± 7 years and 55% were male. Contralateral stenosis of >60% was present in 61 (20%) patients. Seventy-seven percent of patients were on BMT. At a mean follow-up of 40 ± 10 months, 7 ipsilateral strokes (2.3%) and 11 transient ischemic attacks (TIA) (3.6%) occurred for a total of 16 CIE (5.2%; 2 patients experienced both TIA and stroke). At the 4-year follow-up the freedom from ipsilateral ischemic events was 94 ± 2%, with 1.5% annual CIEs. Plaques progression was associated with a significant lower freedom from CIE: 91 ± 4.3% vs 95 ± 1.7% (P = .05). The mid-term results of this prospective study suggest that the rate of CIE is higher than expected in patients under BMT and that plaque progression is the main predictor of new cerebral events. These data should be considered in the current carotid endartecetomy efficacy debate.