Vascular and Perivascular Role in the Regulation of Angiogenesis: Impact on Arteriovenous Fistula Maturation.

Arteriovenous fistula (AVF) is a surgical connection between an artery and a vein created in patients with end-stage renal disease needing dialysis. A major concern with AVF is maturation failure which results, while creating a new AVF, a troublesome process for the patients. Thus, maturation of AVF is important which is achieved by outflow tract outward remodeling. However, vessel stenosis, hypoxia, endothelial dysfunction, and thrombosis contribute to AVF failure. Vascular stenosis and thrombosis after intimal injury due to intimal hyperplasia followed by plaque formation are major factors contributing to AVF maturation failure. Angiogenesis during plaque formation is important and plays a critical role but is also involved in vessel stenosis if uncontrolled. This suggests the dual role of angiogenesis and its effects on AVF maturation. Thus, it is critical to understand the factors regulating neoangiogenesis after the creation of AVF. Not only the angiogenesis in the plaque area but also in the adjoining tissues including muscles due to injury and the factors released by the perivascular structure may influence the angiogenesis and AVF maturation process. This review article comprehensively and critically discusses the role of neoangiogenesis in AVF maturation and the role of various factors regulating angiogenesis (pro- and anti-angiogenic factors) with their potential role in AVF maturation.