Preliminary Study On The Mechanism Of Carotid Artherosclerosis In Patients With Hypertension And Insulin Resistance

Objective: To observe the carotid intima-media thickness (IMT) and plaque in patients with hypertension and insulin resistance . Furthermore to investigate the effect of serum asymmetric dimethylarginine (ADMA) on carotid atherosclerosis in patients with insulin resistance.Method: Sixty patients with essential hypertension were recruited. According to the level of homeostasis model assessment(HOMA-IR), thirty-five patients were classified as essential hypertension with insulin resistant (EH with IR) ,and twenty-five as essential hypertension without insulin resistant(EH without IR). Another 20 healthy individuals were selected as the control groups. Blood pressure, height weight were measured; Fasting serum glucose, insulin, triglycerides, total cholesterol, HDL cholesterol and LDL cholesterol were also analyzed; HOMA-IR was calculated as a measure of insulin resistance; Serum concentrations of ADMA levels were measured by the high-performance liquid chromatography(HPL-C) method; Carotid IMT and plaque were measured by high-resolution ultrasonography.Result: (1) Common carotid artery IMT(CCA-IMT) in patients of EH with IR were higher than those in EH without IR and controls(P< 0.05, P<0.01), The incidence of carotid plaques was also higher than that in controls (P < 0.05). (2) Serum concentrations of ADMA were significantly increased in EH with IR as compared with those in EH without IR and controls(P<0.01, P<0.01), the levels of ADMA in EH without IR were significantly higher than those in controls(P<0.01); (3) In patients with hypertension, both CCA-IMT and serum concentration of ADMA were positively correlated with insulin resistance(r=0.306, P< 0.05; r=0.370, P<0.01). There was positive correlation between ADMA level and CCA-IMT(r=0.381, P<0.01); (4) On multiple regression analysis, ADMA level is the independent determinant of IMT in patients with essential hypertension.Conclusion: (1) Hypertension with insulin resistance promotes carotid atherosclerosis; (2) Carotid IMT is an index of previous atherosclerosis in hypertension. (3) Serum concentrations of ADMA level were related to insulin resistance and carotid atherosclerosis. Increased serum ADMA level maybe played an important role in progression of early atherosclerosis in patients with insulin resistance.