A palpable “thrill” is traditionally associated with success following arteriovenous fistula (AVF) surgery. A thrill typically characterizes turbulent flow and this is a paradox as turbulence is a driver of neointimal hyperplasia. Spiral laminar flow (SLF) has been described as normal and protective pattern of flow in native arteries and is associated with superior patency in bypass grafts that generate it. The aim of this study was to define the pattern of flow within AVFs immediately post-operatively and at follow-up to assess maturation.
Doppler ultrasound was used immediately post-operatively and at follow-up (6 weeks). Blood flow was assessed as SLF or non-SLF. Two blinded qualified observers analysed the images. Patients were followed up for 6 months. Maturation was statistically analysed against the type of flow.
Sequential patients having AVF surgery (n=56) were assessed: 46 (82%) patients had a thrill, 3 patients had no flow and 7 patients had pulsatile flow without a palpable thrill. SLF was present in 80% of those with a thrill but not in any without a thrill (p<0.0001). At follow-up (n=51) 41, patients had a matured AVF (80%), of which 76% had SLF immediately post-operatively. Only one patient with SLF failed to mature. In the non-SLF group 5 of the 15 AVFs failed to mature (66%; p<0.005).
SLF was strongly supportive of successful fistula maturation. A “thrill” was characteristic of spiral rather than turbulence. The mechanism of this apparent beneficial effect of this pattern of flow requires further investigation.
In healthy individuals arterial blood flow has been characterized as having a spiral laminar pattern (Stonebridge P et al 1991). A loss of this pattern of flow is associated with pathology (Houston G et al 2004). (more…)
In non-atherosclerotic vessels, flow is predominantly ‘spiral laminar’ rather than laminar. Spiral Laminar Flow (SLF) stabilises flow patterns at regions of arterial branching. (more…)
Recent work in cardiac and peripheral vascular blood flow has shown evidence for an elegant complexity to flow within the heart and in the large to medium arteries. (more…)
Spiral or helical arterial blood flow patterns have been widely observed in both animals and humans. The absence of spiral flow has been associated with carotid arterial disease. (more…)
To determine the effect of age, sex, and presence of carotid atheromatous disease on the presence of aortic spiral blood flow pattern using two-dimensional flow quantitative magnetic resonance imaging (MRI).
Four-dimensional magnetic resonance MR velocity mapping was developed to study normal flow patterns in the thoracic aorta using time-resolved cardiac gated three-directional velocity data. (more…)
Blood flow patterns are poorly understood despite their impact on arterial disease. (more…)
Helical and retrograde secondary flows have been recorded in the aorta, but their origins and movements in relation to the arch have not been clarified. We set out to do this using magnetic resonance velocity mapping.
Spiral blood-flow patterns in infrainguinal blood-vessels were observed at angioscopy in 54 patients who underwent peripheral vascular reconstruction; the endoluminal surface had spiral folds in 51 of 75 arteries examined. (more…)