Evolving determinants of carotid atherosclerosis vulnerability in asymptomatic patients from the MAGNETIC observational study

MRI can assess plaque composition and has demonstrated an association between some atherosclerotic risk factors (RF) and markers of plaque vulnerability in naive patients. We aimed at investigating this association in medically treated asymptomatic patients. This is a cross-sectional interim analysis (August 2013–September 2016) of a single center prospective study on carotid plaque vulnerability (MAGNETIC study). We recruited patients with asymptomatic carotid atherosclerosis (US stenosis > 30%, ECST criteria), receiving medical treatments at a tertiary cardiac rehabilitation. Atherosclerotic burden and plaque composition were quantified with 3.0 T MRI. The association between baseline characteristics and extent of lipid-rich necrotic core (LRNC), fibrous cap (CAP) and intraplaque hemorrhage (IPH) was studied with multiple regression analysis. We enrolled 260 patients (198 male, 76%) with median age of 71-y (interquartile range: 65–76). Patients were on antiplatelet therapy, ACE-inhibitors/angiotensin receptor blockers and statins (196–229, 75–88%). Median LDL-cholesterol was 78 mg/dl (59–106), blood pressure 130/70 mmHg (111–140/65–80), glycosylated hemoglobin 46 mmol/mol (39–51) and BMI 25 kg/m2 (23–28); moreover, 125 out of 187 (67%) patients were ex-smokers. Multivariate analysis of a data-set of 487 (94%) carotid arteries showed that a history of hypercholesterolemia, diabetes, hypertension or smoking did not correlate with LRNC, CAP or IPH. Conversely, maximum stenosis was the strongest independent predictor of LRNC, CAP and IPH (p < 0.001). MRI assessment of plaque composition in patients on treatment for asymptomatic carotid atherosclerosis shows no correlation between plaque vulnerability and the most well-controlled modifiable RF. Conversely, maximum stenosis exhibits a strong correlation with vulnerable features despite treatment.