Imaging signs of carotid plaque vulnerability predict subclinical neurological events in asymptomatic patients: the carotid artery multi-modality imaging prognostic study

Abstract Background Carotid artery plaques should be considered for invasive treatment if diameter stenoses is ≥60%, in the presence of clinical and/or imaging characteristics associated with an increased risk of ipsilateral stroke, such as intraplaque haemorrhage (IPH) or lipid-rich necrotic core (LRNC). However, little is known about plaque’s characteristics in patients with <60% stenoses. Purpose To evaluate the prevalence and significance of imaging signs of plaque vulnerability in patients with asymptomatic <60% carotid artery stenoses. Methods In the Carotid Artery Multi-modality imaging Prognostic (CAMP) study (granted by Bando Ricerca Salute 2018 - Regione Toscana) we prospectively enrolled 200 patients with asymptomatic, mild/moderate (40-60%) carotid artery stenoses, as assessed at Doppler ultrasound (DUS). All patients were evaluated with multimodality imaging, including computed tomography angiography (CTA), magnetic resonance angiography (MRA) and brain magnetic resonance imaging (MRI), whenever not contraindicated. A subgroup of 75 patients underwent also a 18[F]-fluorodeoxyglucose (FDG) positron emission tomography (PET). A thorough clinical, biochemical, cardiological and neurological evaluation was performed in all patients. Results Imaging signs of plaque vulnerability were frequent (IPH and/or LRNC at MRA were found in 26.3% patients, plaque ulceration at CTA was found in 36.7% of patients). No difference in the prevalence of cardiovascular risk factors was noted in those with and without signs of vulnerability. Subclinical embolic brain infarctions at brain MRI were found in 8.8% of patients at enrollment. These patients had more frequently a LRNC at MRA than patients without subclinical embolic brain infarctions (50% vs 17%, p<0.05), lower estimated glomerular filtration rate (55±8 vs 73±23 mL/min/1.73mq, p<0.001), higher troponin HS values (16±4 vs 12±8 ng/ml, p<0.05). Presence of LRNC at MRA was the only predictor of embolic lesions at MRI (odds ratio 4.86, 95% confidence interval 1.08-21.8, p<0.05). Conclusions Imaging signs of vulnerability are highly prevalent in patients with asymptomatic intermediate carotid artery stenosis. Presence of a LRNC at MRA is associated with subclinical embolic brain infarcts. The use of non-invasive multi-imaging can better characterize carotid plaques, independent of the degree of stenosis, and help identifying a subgroup of patients at higher risk of events.