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Introduction Peripheral arterial disease (PAD) is a key risk factor for cardiovascular disease, foot ulceration and lower limb amputation in people with diabetes. Early diagnosis of PAD can enable optimisation of therapies to manage these risks. Its diagnosis is fundamental, though challenging in the context of diabetes. Although a variety of diagnostic bedside tests are available, there is no agreement as to which is the most accurate in routine clinical practice. The aim of this study is to determine the diagnostic performance of a variety of tests (audible waveform assessment, visual waveform assessment, ankle brachial pressure index (ABPI), exercise ABPI and toe brachial pressure index (TBPI)) for the diagnosis of PAD in people with diabetes as determined by a reference test (CT angiography (CTA) or magnetic resonance angiography (MRA)). In selected centres, we also aim to evaluate the performance of a new point-of- care duplex ultrasound scan (PAD-scan). Methods and analysis A prospective multicentre diagnostic accuracy study ( ClinicalTrials. gov Identifier NCT05009602). We aim to recruit 730 people with diabetes from 18 centres across the UK, covering primary and secondary healthcare. Consenting participants will undergo the tests under investigation. Reference tests (CTA or MRA) will be performed within 6 weeks of the index tests. Imaging will be reported by blinded consultant radiologists at a core imaging lab, using a validated scoring system, which will also be used to categorise PAD severity. The presence of one or more arterial lesions of ≥50% stenosis, or tandem lesions with a combined value of ≥50%, will be used as the threshold for the diagnosis of PAD. The primary outcome measure of diagnostic performance will be test sensitivity. Ethics and dissemination The study has received approval from the National Research Ethics Service (NRES) (REC reference 21/PR/1221). Results will be disseminated through research presentations and papers., National Institute for Health Research (NIHR) NIHR131855, NIHR Clinical Lectureship NIHR Imperial Biomedical Research Centre (BRC)

Background Studies suggest the physical and mechanical properties of vessel walls and plaque may be of clinical value in the diagnosis and treatment of cardiovascular atherosclerotic disease. The purpose of this pilot study was to investigate the potential clinical application of ultrasound Tissue Doppler Imaging (TDI) of Arterial Wall Motion (AWM) and to quantify simple wall motion indices in normal and diseased carotid arteries. Methods 224 normal and diseased carotid arteries (0–100% stenoses) were imaged in 126 patients (age 25–88 years, mean 68 ± 11). Longitudinal sections of the carotid bifurcation were imaged using a Philips HDI5000 scanner and L12-5 probe under optimized TDI settings. Temporal and spatial AWMs were analyzed to evaluate the vessel wall displacements and spatial gradients at peak systole averaged over 5 cardiac cycles. Results AWM data were successfully extracted in 91% of cases. Within the carotid bifurcation/plaque region, the maximum wall dilation at peak systole ranged from -100 to 750 microns, mean 335 ± 138 microns. Maximum wall dilation spatial gradients ranged 0–0.49, mean 0.14 ± 0.08. The AWM parameters showed a wide variation and had poor correlation with stenoses severity. Case studies illustrated a variety of pertinent qualitative and quantitative wall motion features related to the biophysics of arterial disease. Conclusion Our clinical experience, using a challenging but realistic imaging protocol, suggests the use of simple quantitative AWM measures may have limitations due to high variability. Despite this, pertinent features of AWM in normal and diseased arteries demonstrate the potential clinical benefit of the biomechanical information provided by TDI.

We read the article by Thapar et al. with interest and have a number of concerns regarding the methodology used in their study. From the article, it is not clear whether the clinical vascular scientists who took part were formally trained in the two methods of aorta/aneurysm diameter measurements. If the vascular scientists had a preference for one method of measurement in their routine practice, then this would bias the outcome of their measurements. Sonographers in the NHS Abdominal Aortic Aneurysm Screening Programme (AAASP) undergo formal training and the issue of placement of measurement calipers (particularly in identifying thrombus where confusion can arise) is carefully addressed. Therefore, it would be more valid if the sonographers in this study had been compared with those fully accredited by the NHSAAASP. We also have concern about the capture of the image used in Figure 2, given by the authors as an example of ultrasound diameter measurement. This image would fail the quality assurance requirements of the NHSAAASP with particular respect to the excessively high gain used at the posterior wall of the aneurysm. This makes it almost impossible to identify either the outer or inner wall. There is currently much debate on which method of AAA measurement is more reliable. We feel that effort should be made to ensure that correct methodology is used before discrediting one or the other method.

Background Venous ulceration is a significant clinical problem to both clinicians and patients. To optimize the management of patients with ulcers a single-visit, dedicated venous ulcer assessment clinic was set up. Methods All patients referred to the clinic during the first year were recorded prospectively. Each patient was assessed clinically and with colour-coded venous and, where indicated, arterial duplex scanning. Ulcers were classified as venous, arterial, mixed or non-vascular on a basis of ankle : brachial pressure indices and venous duplex scanning. Results Eighty-eight patients (104 limbs with ulcers) were assessed. Seventy-nine per cent of ulcers were venous, 2 per cent arterial, 12 per cent mixed and 7 per cent non-vascular. Of the 95 limbs with demonstrable venous reflux, reflux was confined to the superficial system in 57 per cent, the deep system in 6 per cent and was combined in 37 per cent of limbs. Of the 22 patients who reported previous deep vein thrombosis, nine had normal deep vein function. Some 38 per cent of limbs with no history of previous thrombosis had abnormal deep vein function. Conclusion In this clinic 14 per cent of leg ulcers had a significant arterial component and over half of venous ulcers may benefit from superficial venous surgery. In many ulcerated limbs, clinical assessment alone is inadequate to detect superficial reflux or previous deep vein thrombosis.