Plaque progression in asymptomatic carotid stenosis in the best medical therapy era: is the medical approach sufficient to prevent it?

BACKGROUND: Carotid atherosclerotic disease is a leading cause of mortality and morbidity in the Western world. The evolution of a carotid artery plaque is a complex process, not yet fully understood. The current literature is debating about the correct management of patients with asymptomatic internal carotid artery stenosis. This study analyses the quantitative plaque progression in a cohort of patients characterized by moderate to severe asymptomatic internal carotid artery stenosis and mostly in best medical therapy (BMT).METHODS: The present article describes a sub-analysis of CARAS (carotid asymptomatic stenosis) observational study data (trial registration number: NCT04825080). In this monocentric prospective observational cohort study, patients with ≥60-99% asymptomatic internal carotid artery stenosis (NASCET criteria), and mostly in BMT, were enrolled. They were considered unfit for surgical treatment due to significant comorbidities and/or low life expectancy (<3 years). The plaque progression was evaluated by a six-month telephone interview associated with an annual anamnestic, vascular surgical, and ultrasonographic duplex ultrasound scanning (DUS) examination. The primary endpoint was to determine the quantitative progression of carotid plaque during the follow-up period. The secondary endpoints were to evaluate the contralateral quantitative progression of carotid plaque, the compliance to BMT, the ipsilateral neurological ischemic events (transient ischemic attacks (TIA), amaurosis fugax, and stroke) rate, and the survival in this subgroup of patients.RESULTS: Three hundred and seven patients were recruited between January 2019 and March 2020. The total patients mean age was 80±7 years. The mean follow-up was 41±9 months. During the follow-up a quantitative plaque progression was observed in 18.9% (N.=58) of overall cases. In this subgroup of patients, the mean age was 81±7 years. Five (8.6%) patients presented a contralateral quantitative plaque progression. At the end of the follow-up, an increase of the patients compliance to BMT (87.9% [N.=51] vs. 82.8% [N.=48]) was assessed. During the study period, nine out of 307 total patients (2.9%) presented an ipsilateral TIA and two of them suffered a stroke after the TIA. Of the nine total neurological ischemic events observed, seven (six ipsilateral TIA and one stroke) occurred in the subgroup of patients with plaque progression. A total of six (10.3%) patients were involved. One of them experienced recurrent TIA and a moderate stroke (NIHSS: 12) immediately after. This patient underwent an urgent endarterectomy. During the follow-up period a total of 34 (11%) patients died, with a total survival rate of 85±2%. However, in the subgroup of patients with quantitative plaque progression a total of 3 (5.2%) patients died and, consequently, a survival rate of 94.8±2% was assessed.CONCLUSIONS: Despite the high compliance to BMT, a considerable percentage of plaque progression was observed. Interestingly, the most of cerebral ischemic events observed during the follow-up just occurred in these patients. Therefore, these results suggest the failure of BMT alone in the prevention of internal carotid artery plaque progression and cerebral ischemic events related to it.