Is there a role of angiotensin-converting enzyme gene polymorphism in the failure of arteriovenous femoral shunts for hemodialysis?

In humans, thrombosis and neointimal hyperplasia are the major factors resp onsible for prosthetic graft occlusion. Previous studies suggest that the r enin-angiotensin system is one of the key enzymes in the vascular system an d has been implicated in the pathogenesis of thrombosis and neointimal hype rplasia. We conducted a case-control study to determine the frequency of th e different angiotensin-converting enzyme (ACE) genotypes among the patient s who had PTFE graft implantation for hemodialysis access. Between 1997 and 1999, 30 graft implantations were performed. Twelve individuals (40%) deve loped thrombotic complications, 8 of the 12 patients had ACE ID polymorphis m, and 2 patients had DD and 2 patients had II polymorphism. The ID polymor phism was significantly more frequent in the thrombosed arteriovenous (A-V) grafts than in nonthrombosed A-V grafts (chi (2) = 7.57 and p = 0.02). Ove rall, the frequency of the D and I alleles was 66.6 and 33.3%, respectively . In conclusion, ID polymorphism of the ACE gene plays an important role in the pathogenesis of vascular access thrombosis in subjects undergoing hemo dialysis for chronic renal failure.