Hemodynamic study on upper extremity: simulation on straight reverse saphenous vein graft

Artery reconstruction in upper extremities is rare performed compare to the incidence of reconstruction in lower extremities. In many cases, primary vascular repair was performed, whenever, otherwise, the interposition vein graft or venous bypass grafting were used in order to alleviate vascular occlusion. However, after grafting technique are applied, one or more of the digital arteries are blocked or severely narrowed because of mismatch of end-to-side or end-to-end reverse saphenous vein graft. The objective of this study was to understand the end-to-end blood flow influence on reverse saphenous vein graft with small diameter. The finite volume method was employed to model the 3-D blood flow pattern to determine the velocity, pressure gradient, flow, wall shear stress, flow resistance and longitudinal impedance (ZL). We expected that reverse saphenous vein graft behave hydraulically like provide straight graft. Furthermore longitudinal impedance modulus (ZL) is expected to be inverse proportional to small diameter

Computational fluid dynamic analysis on microvascular vein grafting: effect of mismatched conduit diameters

An artery disease of upper extremity is uncommon happened. The most common cause of artery disease in upper extremity is atherosclerosis. In few patients with artery disease, surgical vein bypassing or vein interposition is frequently performed. However, one or more the internal diameters of applied vein graft are blocked or severely norrowed due to the mismatched diameter between existing artery and vein graft. The objective of this study is to investigate the blood flow influence on vein graft with mismatched diameter failure. The 3-D computational fluid dynamic method was employed to determine pulsatile flow velocity, pulsatile pressure gradient, and wall shear stress impact on the mismatched diameter of artery-vein graft model. We expect that pulsatile flow velocity, pulsatile pressure gradient, and wall shear stress impact on mismatched diameter of artery-vein graft model to behave non-hydraulically compared to an ideal matched model

CFD analysis on mismatched end-to-end internal diameter of RSVG models

A digital arterial disease in upper extremity is uncommon happened compare to arterial disease in lower extremity. A surgical vein graft interposition is performed as revascularization procedure. However, mismatching between end-to-end internal diameter of reverse saphenous vein graft (RSVG) and existing digital artery cause blockage in RSVG vessel. In previous study, size discrepancy (small to large) in vessel causes the abnormal blood flow and will initiate the thrombosis formations as stated by Rory F. et al. Furthermore, their previous study is also supported by clinical theory as written in Wilmer W. et al. and Krishnan B. Chandran et al.s’ text books. The main goal of this study is to analyze the relationship the patterns of blood flow through mismatching between end-to-end internal diameter of RSVG models and existing digital artery (large to small) with effect to the initiation of thrombus formation in RSVG models. A Three-dimensional Computational Fluid Dynamic (3-D CFD) method is employed to investigate blood flow velocity, blood pressure gradient and wall shear stress (WSS) on ideal straight (well matched between internal diameter of RSVG and recipient arteries) and internal diameter mismatched of end-to-end RSVG models. In this experiment, we expect that steady state laminar blood flow demonstrates abnormal flow pattern in mismatched internal diameter RSVG models compared to an ideal straight model. As conclusion, any abnormal blood flow pattern will initiate the formation of thrombus and reduce the vein graft survival