Hyperhomocysteinemia and hypercoagulable state in carotid plaque evolution. Novel risk factors or coincidental risk predictors?

Aim: The majority of patients with carotid occlusive disease (COD) have one or more of the conventional risk factors of atherosclerosis. In addition, hyperhomocysteinemia (HHCY) and hypercoagulable state (HCGS) are increasingly recognized as potentially ''novel'' risk factors. The aim of this study was to determine the role of these factors in carotid plaque evolution and clinical manifestation of COD.

Methods: Between September 2003 and 2005, 153 patients were admitted in our Department with clinical and duplex ultrasound evidence of severe (>70%) COD as operative candidates and 33 patients with evidence of moderate (50-69%) stenosis included in the protocol of conservative treatment and lifelong observation. Conventional risk factors of atherosclerotic disease and plasma levels of homocysteine (HCY), fibrinogen (FBG), protein C (PC), protein S, antithrombin III and activated protein C resistance were recorded in all patients. The degree of carotid stenosis was measured in a carotid angiogram following North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria for all operative candidates. Angiographic workup revealed 147 carotid stenoses >70% and 16 internal carotid occlusions in 82 symptomatic and 52 asymptomatic patients, while in 19 patients the carotid stenosis was moderate (50-69%) and these patients included in the conservative treatment group. The study of the ''novel'' and conventional risk factors was performed with univariate and multivariate statistical analysis as well as with correlational analysis of HCY and the other risk factors between patients with severe or moderate COD and between symptomatic and asymptomatic patients with carotid stenosis >70%.

Results: Our data showed that HHCY was a strong independent risk factor of symptomatic carotid disease >70%. In addition, the coexistence of high FBG levels and thrombophilia factor deficiency with HHCY was significantly related with the clinical manifestation of COD.

Conclusion: HHCY and HCGS are often detected among patients with severe and symptomatic carotid stenosis. The early diagnosis and treatment of these deficiencies might be helpful for the management of COD, but their role in future clinical practice is yet to be determined.