Potential of low apolipoprotein A-I as a surrogate marker of vulnerable carotid artery plaques.

Objective: Recent studies suggested that the medical control of atherogenic lipoproteins is not sufficient for stroke prevention. A low apolipoprotein A-I (apoA-I) level may play a crucial role in the anti-atherogenic effects of high-density lipoprotein (HDL-C) and may also be associated with symptomatic vulnerable plaques in carotid artery stenosis. Therefore, the present study investigated the relationship between apoA-I levels and the status of carotid artery stenosis.

Methods: Ninety-one patients with carotid artery stenosis were examined. The status of carotid artery plaques was divided into symptomatic (n = 47) and asymptomatic (n = 44). We examined patient profiles, including comorbidities, and laboratory lipid data, and plaque features visualized by ultrasonography, MRI, and digital subtraction angiography. The relationships between plaque instability and risk factors for carotid artery stenosis were investigated.

Results: No significant differences were observed in the profiles of symptomatic and asymptomatic patients. Regarding plaque features, ulceration, low echo luminance, and a high signal intensity in plaques on T1-weighted images correlated with symptomatic plaques. ApoA-I, total cholesterol, and non-HDL-C levels were significantly lower in symptomatic patients than in asymptomatic patients. A multivariate logistic regression analysis identified low ApoA-I levels, ulceration, and low echo luminance as predictive factors for symptomatic carotid artery stenosis. Diagnostic accuracy for predicting symptomatic carotid stenosis was 0.84 when the following four factors were combined: ulceration, low echo luminance, a high signal intensity on T1-weighted images, and the level of apoA-I.

Conclusions: A low apoA-I level was associated with symptomatic carotid artery stenosis. Therefore, ApoA-I levels have potential as a surrogate marker to detect unstable carotid artery plaques.