Clinical significance of lipoprotein(a) in carotid plaque types and ischemic stroke in the elderly

Background:   The relationship between lipoprotein(a) (Lp(a)) and ischemic stroke is still controversial in the elderly. The purpose of the present paper was to evaluate the significance of Lp(a) in the development of extracranial carotid lesions and ischemic stroke.
Methods:   A total of 371 elderly subjects, studied with carotid ultrasonography (US) and brain computed tomography (CT), was stratified into two groups according to serum Lp(a) levels: the normal Lp(a) and high Lp(a) (>40 mg/dL) groups. Carotid plaques were divided into three types based on the US echogenicity: hypoechoic, hyperechoic, and heterogeneous plaques. Low-density areas (LDA) on brain CT images were classified into three groups depending on their distribution: basal ganglionic, cortical and only leuko-araiosis types.
Results:   The incidence of bilateral carotid lesions and the ratios of hypoechoic and heterogeneous plaques were significantly higher in the high Lp(a) group than in the normal Lp(a) group. Both the mean height and length of plaque were also greater in the high Lp(a) group. Mean Lp(a) levels were significantly elevated in cases with hypoechoic and heterogeneous types, compared to the cases without lesions. Higher mean Lp(a) levels were seen in cases with any kind of LDA than in normal subjects on CT, but there was no significant difference in the incidence of each LDA between the two groups.
Conclusions   These findings indicate that serum Lp(a) is strongly related to carotid lesions, especially hypoechoic and heterogeneous plaque types, in Japanese elderly patients. This suggests that Lp(a) could promote the formation of lipid-rich atheromatous plaque with intraplaque hemorrhage or superimposed thrombi. Serum Lp(a) also seemed to be a risk for all types of LDA.