Hemodynamic considerations in arteriovenous vascular access modalities for hemodialysis.

Arteriovenous fistulas and arteriovenous grafts are the most commonly used vascular access for hemodialysis in patients with end-stage chronic kidney disease. However, both methods face significant challenges due to the hemodynamic disturbances induced by the arteriovenous anastomosis. This causes changes in vascular structure and blood flow velocity near the anastomosis site after the fistula/graft surgery, and introduces abnormal wall shear stress and cyclic stretch. This leads to endothelial cell dysfunction, vascular smooth muscle cell proliferation, and adverse remodeling. The resulting effects include low patency rates due to vascular stenosis caused by intimal hyperplasia and insufficient outward remodeling. Additionally, the high flow conduit has been linked to adverse cardiac remodeling. To address this, various strategies have been explored to correct these localized hemodynamic abnormalities, aiming to improve long-term patency rates. In this review, an overview is provided of the current surgical techniques, anastomosis types, anastomosis angles, external scaffolds, modified fistula designs, and types of grafts. It evaluates the impact of these approaches on local hemodynamics in the access conduit and their potential effects on patient outcomes.