Relationship Between Plasma Homocysteine and the Morphological and Immunohistochemical Study of Carotid Plaques in Patients With Carotid Stenosis Over 70%

Background: Several clinical and epidemiological studies describe hyperhomocysteinemia as an independent cardiovascular risk factor. Implication of cellular immunity in atherosclerosis also seems clear. This study aimed to analyze the association among plasma hyperhomocysteinemia, neurological clinical events, and the morphology and immunocytology of carotid plaques in patients with carotid stenosis >70% receiving surgical treatment. Methods: Sixty-two patients with carotid stenosis >70% receiving surgical treatment were studied; 58% had a history of stroke in the ipsilateral carotid territory. Plasma homocysteine concentrations were determined by considering pathological values > 12.4 mu mol/L. Histopathological (stable and unstable plaques) and immunohistochemical (macrophages, T lymphocytes, and active T lymphocytes counts) studies were performed. Hyperhomocysteinemia prevalence was calculated in this population, as were the possible relationships between homocysteine plasma concentrations, and the carotid plaque type and the cell types in it. The relationship between this risk factor and the presence of a neurological event relating to carotid stenosis was also investigated. Results: Hyperhomocysteinemia prevalence was 43.5%, with a mean value of 11.8 mu mol/L (median; range 2-41.8 mu mol/L). No significant differences were found between homocysteine levels and the plaque's morphological characteristics, or between the cell types analyzed. Elevated concentrations of homocysteine were not significantly higher in patients with a history of stroke. Conclusion: The present study confirms high hyperhomocysteinemia prevalence in patients with extracranial cerebrovascular disease, although no relationship between plaque complication phenomena and this cardiovascular risk factor was observed.