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Cardiovascular system
Published in A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha, Clark’s Procedures in Diagnostic Imaging: A System-Based Approach, 2020
A Stewart Whitley, Jan Dodgeon, Angela Meadows, Jane Cullingworth, Ken Holmes, Marcus Jackson, Graham Hoadley, Randeep Kumar Kulshrestha
Ultrasound: the abdominal aorta, iliac and femoro-popliteal arteries and their distal run-off are all amenable to ultrasound examination, and this will often be performed as the initial test for peripheral arterial disease, particularly if the surgical clinic has an associated vascular laboratory that can provide open access. Typically, an ankle brachial pressure index (ABPI) will be performed initially, a simple ultrasound-assisted measure of pressure at the brachial artery at the elbow, and the ankle; a significant discrepancy may indicate peripheral artery disease. If resting ABPI is normal an abnormal post-exercise ABPI may confirm peripheral arterial disease [92]. A full scan of the peripheral arterial tree may then be performed to localise disease and further assess its severity. Colour and power Doppler ultrasound help to localise vessels and identify flow, and arterial waveform analysis by continuous wave Doppler may reveal attenuation of the normal triphasic waveform of the peripheral arteries, becoming progressively biphasic and ultimately monophasic with increasing severity of peripheral artery disease.
Patient-specific flow descriptors and normalised wall index in peripheral artery disease: a preliminary study
Published in Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, 2018
Jaykrishna Singh, Gerd Brunner, Joel D. Morrisett, Christie M. Ballantyne, Alan B. Lumsden, Dipan J. Shah, Paolo Decuzzi
Peripheral artery disease (PAD) is a vascular disease characterised by the formation of atherosclerotic lesions in lower extremity arteries (Gardner & Afaq 2008; Lim 2013; Bentzon et al. 2014; de Beer et al. 2015; Heinen et al. 2015; Hossain et al. 2015; Walker et al. 2015; Fowkes et al. 2013). PAD is linked with a higher risk of coronary artery disease, myocardial infarction, and cardiovascular death (Newman et al. 1991; Gardner & Afaq 2008; Hossain et al. 2015; Walker et al. 2015). Approximately 27 million people suffer from PAD in Europe and North America (DeRubertis et al. 2007; Heinen et al. 2015). Functional impairment in the lower extremities is a consequence of PAD (Newman et al. 1991; Gardner & Afaq 2008). Intermittent claudication is associated with a 10-year mortality rate of 50% (Lumsden et al. 2007). The optimal medical treatment of PAD consists of standard of care including medical management and surgical treatment (DeRubertis et al. 2007; Lumsden et al. 2007; Brunner et al. 2013; Poredoš et al. 2015; Walker et al. 2015). The formation of atherosclerotic lesions in the arterial system has been attributed to the localised alterations in the blood flow either due to branching or due to pre-existing stenosis (DeRubertis et al. 2007; Lumsden et al. 2007; Hossain et al. 2015). Using an in vitro fluidic system representing the human carotid bifurcation, Ku and colleagues proposed in 1985 that lesions tend to form in areas of low shear stresses and large oscillations in the direction of wall shear may enhance atherogenesis (Ku et al. 1985). These initial observations have been confirmed by various groups (Friedman et al. 1987; Nerem 1992; Giddens et al. 1993; Malek et al. 1999; Caro 2009) emphasising the importance of an accurate determination of the blood flow field, time-averaged wall shear stresses (TAWSS) and oscillatory shear index (OSI). TAWSS gives the wall shear stress magnitude averaged over the cardiac cycle at a specific location of interest and OSI describes the departure of the shear stresses from TAWSS and, therefore, provides an indication of local flow disturbance.
Clinical investigation of the GORE drug-coated PTA balloon catheter for CE mark approval
Published in Expert Review of Medical Devices, 2023
Elias Noory, Gunnar Tepe, Michael Piorkowski, Marcus Thieme, Stefan Müller-Hülsbeck, Klaus Brechtel, Michael Lichtenberg, Ulrich Beschorner, Tanja Böhme, Thomas Zeller
Lower extremity peripheral artery disease (PAD) is a condition in which blood flow in the lower limb arteries has been partially or entirely blocked, most commonly as a result of atherosclerotic lesions within the vessel lumen [1]. PAD is a common condition affecting millions of individuals worldwide [1–3]. In addition to being closely associated with risk factors such as smoking, diabetes mellitus, and race [1,4], PAD becomes increasingly likely with advancing age. PAD affects between 3% and 14% of the general population but may be present in over 30% of those greater than 70 years of age [5–7]. As PAD progresses, the disease may cause intermittent claudication during activity, and, in more severe cases, pain at rest or loss of tissue in the feet and legs. If not adequately addressed, PAD is associated with significant morbidity, and may ultimately result in disability, loss of the affected limb, and death [8]. A number of options exist for the treatment of PAD. These interventions can be grouped into four general categories: (a) behavioral modification, such as smoking cessation or increased exercise; (b) pharmacologic management of certain risk factors, including dyslipidemia and hypertension; (c) revascularization using minimally invasive endovascular techniques, and (d) revascularization using open surgical methods such as endarterectomy or bypass [4,8–10]. The appropriate choice of therapy is heavily dependent upon the severity and location of disease [4,10]. Although surgical revascularization is very effective, endovascular treatment is a first-line treatment for SFA/PA disease, due both to the reduction in significant risk of complications and to the increasing effectiveness of less invasive endovascular procedures [1,11]. Endovascular revascularization can be accomplished using a number of procedural options, including percutaneous transluminal angioplasty (PTA) or the implantation of an endoluminal stent [12]. PTA is a well-established minimally invasive treatment for disease in the superficial femoral and popliteal arteries (SFA/PA). With restenosis rates of 40–60% after 6–12 months, many patients require additional percutaneous or surgical interventions to address their recurrent symptoms [13–15]. Alternative treatments to inhibit restenosis are needed. Paclitaxel drug-coated balloon catheters have shown lower late lumen loss and target lesion revascularization rates compared to uncoated balloons as noted in the FEMPAC, THUNDER, PACIFIER, and In. Pact SFA trials [16–18]. Previous DCB studies that were intended to supply clinical data for CE marking have used uncoated PTA as a comparator for the test paclitaxel drug-coated balloon catheter. Given the prominent role that uncoated PTA balloons continue to play in the endovascular management of PAD lesions, peer-reviewed published data from uncoated PTA balloon catheters was used as the starting point for calculation of a performance goal. Establishing the safety and performance of the GORE DCB Catheter by comparison with a performance goal is appropriate given the maturity and similarity of the procedure, device, and technology to currently CE marked DCBs. Trial design was discussed with and adapted to the suggestions of the competent authority for CE marking (MPA Sweden).