ABSTRACT
BACKGROUND: Neointimal hyperplasia and thrombosis are the major factors responsible for vascular access occlusion. Previous studies suggested that the renin-angiotensin system has been implicated in the pathogenesis of neointimal hyperplasia and thrombosis. Recent studies have shown that angiotensin-converting enzyme (ACE) gene polymorphism may have a association with venous thrombosis. We conducted a retrospective case control study to determine the influence of ACE gene polymorphism on the progression of radiocephalic wrist arteriovenous fistulae (RCAVF). Also, we investigated the association between ACE polymorphism and various thrombotic factors in thrombosed and nonthrombosed subjects. METHODS: 56 patients (24 males and 32 females, mean age 49.8, age range 12-81) whose RCAVF had been maintained in good condition after 2 months of vascular access operation were included in this study. Lipoprotein (a), total cholesterol, C-reactive protein (CRP) and homocystein were measured before hemodialysis session in fasting state. Clinical data such as body mass index (BMI), cigarette smoking, hypertension, and diabetes were retrieved from patient's records. The ACE genotype was analyzed by the polymerase chain reaction (PCR). RESULTS: The incidence of diabetes and cigarette smoking were similar in the three genotypes. There were no significant differences in BMI, total cholesterol, lipoprotein (a), CRP and homocystein (p=0.551, 0.429, 0.279, 0.392, 0.124, respectively) among DD, ID and II genotypes. The percentage of the DD, ID and II genotypes were 16%, 43%, 41%, respectively. Compared with the ID and II genotypes, the proportion of the thrombosed AV shunts was larger in DD genotypes. But there was no statistically significant difference between ACE polymorphism and RCAVF thrombosis (x2=1.027, df=2, p=0.598). ACE polymorphism is shown to have no association with body mass index, blood level of total cholesterol, lipoprotein (a), CRP and homocystein. CONCLUSION: These results suggest that ACE polymorphism may have some influences on the vascular access occlusion in maintenance hemodialysis patients and have no relationship with body mass index, total cholesterol, lipoprotein (a), CRP and homocystein.