Towards the Identification of Hemodynamic Parameters Involved in Arteriovenous Fistula Maturation and Failure: A Review

Abstract

Native arteriovenous fistulas have a high failure rate mainly due to the lack of maturation and uncontrolled neo-intimal hyperplasia development. Newly established hemodynamics is thought to be central in driving the fistula fate, after surgical creation. To investigate the effects of realistic wall shear stress stimuli on endothelial cells, an in vitro approach is necessary in order to reduce the complexity of the in vivo environment. After a systematic review, realistic WSS waveforms were selected and analysed in terms of magnitude, temporal gradient, presence of reversing phases (oscillatory shear index, OSI) and frequency content (hemodynamics index, HI). The effects induced by these waveforms in cellular cultures were also considered, together with the materials and methods used to cultivate and expose cells to WSS stimuli. The results show a wide heterogeneity of experimental approaches and WSS waveform features that prevent a complete understanding of the mechanisms that regulate mechanotransduction. Furthermore, the hemodynamics derived from the carotid bifurcation is the most investigated (in vitro), while the AVF scenario remains poorly addressed. In conclusion, standardisation of the materials and methods employed, as well as the decomposition of realistic WSS profiles, are required for a better understanding of the hemodynamic effects on AVF outcomes. This standardisation may also lead to a new classification of WSS features according to the risk associated with vascular dysfunction.

Flow-induced, inflammation-mediated arterial wall remodeling in the formation and progression of intracranial aneurysms

“…37 Surgical arteriovenous fistulas created to enable hemodialysis provide clear evidence that this flow-induced vessel remodeling takes place in humans. 23,64 In these fistulas, the lack of capillary bed resistance produces an abnormally high flow, which leads to outward remodeling to a size multiple times larger than the original, especially in the draining vein 64 also subjected to higher than intended pressure in addition to abnormally high flow. Experimental models of surgically created arteriovenous fistulas demonstrate that this flow-induced outward remodeling occurs through a coordinated sequence of protease expression followed by synthesis of new collagen.…”

Initial single-center experience with a new external support device for the creation of the forearm native arteriovenous fistula for hemodialysis

“…Among the mechanical factors, wall shear stress, pressure drop and intimal hyperplasia are reported. 21 In their review, Al Shakarchi et al 22 studied the following risk factors of vascular access loss: age, vein diameter, cardiovascular disease, previous vascular access, hypotension, diabetes, and central venous catheter positioned on the same side of the vascular access.…”

The biology of bone morphogenetic protein signaling pathway in cerebrovascular system

“…The irregular wall shear stress caused by abnormal hemodynamics is often accompanied by a series of vascular disorders. In the intracranial vessels, cerebral aneurysm, arteriovenous malformation, and arteriovenous fistula are closely related to abnormal hemodynamics [ 38 – 40 ]. When the blood flow parameters change, the abnormal wall shear stress is sensed by the cilia and polysaccharide protein complex on the membrane surface of vascular endothelial cells, and the wall shear stress stimulation is transformed into biological signal through the ion channel on the membrane surface.…”