Endothelial Function Predicts Positive Arterial-Venous Fistula Remodeling in Subjects with Stage IV and V Chronic Kidney Disease

Abstract

Purpose The maturation of an arterio-venous fistula (AVF) requires remodeling of the arterial inflow and the venous outflow limbs to sustain flows sufficient to support hemodialysis. However, factors influencing remodeling of AVF are poorly understood. We hypothesized that AVF remodeling was an endothelium-dependent process. Methods This is a prospective cohort study of patients (n=25) undergoing autologous AVF formation. Brachial artery vasoreactivity studies were performed preoperatively to assess endothelium-dependent, flow-mediated vasodilation (FMD). High-resolution ultrasound was used to assess venous and arterial diameters intraoperatively, and at 3 months. Results The mean age was 64.5 ± 13.6 years. Twelve subjects (48%) had diabetes. The mean FMD for the entire cohort was (mean ± SEM) 5.82 ± 0.9%, (range) 0–17.3%. The vein increased in size 3.19 ± .28 to 6.11 ± .41 mm, 108.4 ± 17.9%, p=.0001, while the artery increased from 3.29 ± .14 to 4.48 ± .30 mm, 20.47 ± 10.8%, p=.013. There was a significant positive correlation between the degree of arterial and venous remodeling, r=.52, p=.023. Brachial artery FMD most strongly correlated with the magnitude of arterial remodeling, r=.47, p=.038. Patients with diabetes failed to undergo venous remodeling to the same extent as did those without diabetes, 59.2 ± 24.4% vs. 141.5 ± 25.4%, p=.04. Conclusion Impairment of endothelial function is associated with decreased arterial remodeling and final venous lumen diameter attained at three months. Further investigation is needed to determine whether modulation of endothelial function in this cohort can improve AVF maturation.

An overview of AVF maturation and endothelial dysfunction in an advanced renal failure

“…Owens et al [45] determined FMD among 25 CKD patients prior to AVF creation and found very similar values (5.8 ± 1.0%). Study explored the correlation between baseline FMD and subsequent change in the diameter of the artery and vein at 3 months after AVF creation and found a positive correlation.…”

Influence of diabetes and perivascular allogeneic endothelial cell implants on arteriovenous fistula remodeling

“…Recently, we examined the influence of baseline endothelial function, as measured using brachial artery flow-mediated dilation (FMD), on the subsequent remodeling of artery and vein post-AVF creation. 36 In this study, we determined that there was a positive correlation between arterial and venous enlargement post-AVF, and positive remodeling was correlated with baseline brachial FMD measured in the ipsilateral extremity. In addition, a negative relationship between diabetes and venous remodeling was observed in that cohort, and confirmed by findings in the current study.…”

Incomplete Restoration of Homeostatic Shear Stress Within Arteriovenous Fistulae

“…It is important to first characterize the hemodynamics in patent accesses in order to eventually understand the negative influence of hemodynamics in failing accesses [11]. It is furthermore unlikely that effective clinical treatments for fistula maturation will be successful until a more precise characterization of fistula hemodynamics is articulated [10].…”

“…The renormalization of shear stress in the fistula vessels has been interpreted as evidence of a "mechanical homeostasis" [9]: the vessels seek to maintain a preferred mechanical state through a process of growth and remodeling. The shear-induced remodeling is widely hypothesized to be regulated in part by the vascular endothelium [10].…”