Significance of Clopidogrel Resistance Related to the Stent-Assisted Angioplasty in Patients with Atherosclerotic Cerebrovascular Disease

OBJECTIVE: To evaluate the prevalence and risk factors of clopidogrel resistance, and association between thromboembolic complications and clopidogrel resistance in patient with stent-assisted angioplasty for atherosclerotic cerebrovascular disease. METHODS: Between September 2006 and June 2008, clopidogrel resistance test was performed on 41 patients who underwent stent-assisted angioplasty for atherosclerotic cerebrovascular disease. It was performed before drug administration and about 12 hours after drug administration (loading dose : 300 mg, maintain dose : 75 mg). Two patients were excluded, and 41 patients were included (mean : 67.59+/-7.10 years, age range : 41-79). Among 41 patients, 18 patients had intracranial lesions, and 23 had extracranial lesions. We evaluated the prevalence, risk factors and complications related to clopidogrel resistance. RESULTS: Twenty-one patients (51.2%) showed clopidogrel resistance [intracranial : 10 patients (55.6%), extracranial : 11 patients (47.8%)] and no clopidogrel resistance was seen in 20 patients. Hypercholesterolemia was an indepedent risk factor of clopidogrel resistance. Stent-assisted angioplasty was technically successful in all patients, but acute in-stent thrombosis occurred in 5 patients with intracranial lesions (4 patients with clopidogrel resistance and 1 without clopidogrel resistance). Acute thrombi were completely lysed after intra-arterial infusion of abciximab. CONCLUSION: There was relatively high prevalence of clopidogrel resistance in patients with atherosclerotic cerebrovascular disease. Hypercholesterolemia was an independent predictive factor of clopidogrel resistance. Acute in-stent thrombosis was more frequently seen in the clopidogrel resistant group. Therefore, clopidogrel resistance test should be performed to avoid thromboembolic complications related to stent-assisted angioplasty for atherosclerotic cerebrovascular disease, especially patients with hypercholeterolemia and intracranial lesion.

Vascular Endothelial Growth Factor-C Expression in Primary and Metastatic Brain Tumor

OBJECTIVE: Vascular endothelial growth factor(VEGF)-C is involved in lymphangiogenesis and spreading of cancer cells via lymphatic vessels. The aim of the present study is to investigate the relationship between the absence of cerebral lymphatic vessels and low metastatic rate of brain tumors. METHODS: Immunohistochemical stains were performed for VEGF-C and VEGF in surgically resected specimens from 57 patients with primary(38 cases, low grade : 10 cases, high grade : 28 cases) and metastatic(19 cases) brain tumor. RESULTS: The expression of VEGF-C was higher in metastatic carcinoma(68%) than in high-grade primary tumor(29%). There was no difference for VEGF expression between high grade brain tumor (71%) and metastatic carcinoma(58%). CONCLUSION: Low VEGF-C expression of primary brain tumors may play a role in low metastatic rate of brain tumors.