Hemodynamics of arterial stenosis

Abstract

In order to derive a better understanding of the effect of varying degrees of stenosis on arterial pulsatile waveforms, an in vitro model was constructed and in vivo studies were done in dogs to observe and record the changes in the pulsatile and steady arterial blood flow components. Blood flow measurements were made using the electromagnetic blood flowmeter proximal and distal to the stenosis. The data show that as the degree of stenosis increases, the decreases in the pulsatile components of flow and distal pressure occur earlier and to a much greater degree than changes in mean flow.

Does ‘intestinal angina’ exist? A critical study of obstructed visceral arteries

“…Finally, an intraluminal diameter reduction of 50 per cent is equivalent to an intraluminal cross-section area of just under 80 per cent. Although reduction in pulsatile flow and distal pressure occurs before this level is reached (13), mean blood flow is not affected until a stenosis has reduced the intraluminal cross-section area by 80 per cent (14). Hence the choice of a 50 per cent intraluminal diameter reduction as a 'critical stenosis'.…”

Reduction of early vein graft thrombosis by tissue plasminogen activator gene transfer

“…After equilibration the graft was given a stenosis sufficient to abolish the reactive hyperaemic response. Flow and CFR production was then measured at 0 or ~90% stenosis (10% of normal flow ) (17), with or without the graft being repeatedly 'pinched' by a haemostat to mimic endothelial damage (9, 10). The contralateral graft was subsequently examined (not Day 0 animals).…”

“…CFRs were frequent, despite the presence of heparin within the circulation (as has been previously described [9,10]). CFR frequency in arteries was not influenced by the degree of stenosis, once a 'critical stenosis' (>70% reduction in flow) was produced (11,17). As blood flow between 70-95% stenosis is directly proportional to the fraction of original flow (17), all experiments in the engrafted arteries were performed without stenosis or at 10% of the original flow.…”

“…CFR frequency in arteries was not influenced by the degree of stenosis, once a 'critical stenosis' (>70% reduction in flow) was produced (11,17). As blood flow between 70-95% stenosis is directly proportional to the fraction of original flow (17), all experiments in the engrafted arteries were performed without stenosis or at 10% of the original flow. Reduction of blood flow had no effect on CFR frequency, formation and resolution, or severity (Table 1), nor did damage to the grafts by repeated pinching (data not shown).…”

Impact of proximal and distal cuff inflation on brachial artery endothelial function in healthy individuals

“…Altered shear stress patterns have been observed both proximal and distal to a stenosis (Koskinas et al 2009;Laughlin et al 2008;Lee et al 1978) and from cuff inflation (Betik et al 2004;Schreuder et al 2014;Thijssen et al 2009;Tinken et al 2009). In keeping with the stenosis analogy (Ku 1997; Lee et al 1978), a drop in transmural pressure may be present distal, but not proximal, from a partially inflated cuff (Anderson et al 1979;Bache and Schwartz 1982;de Leeuw et al 2018). Accordingly, cuff manipulation may represent a non-invasive model to assess the impact of hemodynamics on endothelial function.…”