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The first accounts of measuring cerebral blood flow (CBF) in humans were made by Angelo Mosso in ~1880, who recorded brain pulsations in patients with skull defects. In 1890, Charles Roy and Charles Sherrington determined in animals that brain pulsations—assessed via a similar method used by Mosso—were altered during a variety of stimuli including sensory nerve stimulation, asphyxia, and pharmacological interventions. Between 1880 and 1944, measurements for CBF were typically relied on skull abnormalities in humans. Thereafter, Kety and Schmidt introduced a new methodological approach in 1945 that involved nitrous oxide dilution combined with serial arterial and jugular venous blood sampling. Less than a decade later (1950’s), several research groups employed the Kety-Schmidt technique to assess the effects of exercise on global CBF and metabolism; these studies demonstrated an uncoupling of CBF and metabolism during exercise, which was contrary to early hypotheses. However, there were several limitations to this technique related to low temporal resolution and the inability to measure regional CBF. These limitations were overcome in the 1960’s when transcranial Doppler ultrasound (TCD) was developed as a method to measure beat-by-beat cerebral blood velocity. Between 1990 and 2010, TCD further progressed our understanding of CBF regulation and allowed for insight into other mechanistic factors, independent of local metabolism, involved in regulating CBF during exercise. Recently, it was discovered that TCD may not be accurate under several physiological conditions. Other measures of indexing CBF such as Duplex ultrasound and magnetic resonance imaging, although not without some limitations, may be more applicable for future investigations.

IntroductionPeripheral arterial disease (PAD) affects approximately one in five people over 60 in the UK. In severe cases, revascularisation, such as surgical bypass or endovascular methods, is often required to restore limb perfusion. Between 2000 and 2019, 527 131 revascularisation procedures were carried out in the UK. Postprocedural surveillance is essential to detect restenosis and maintain vessel patency. However, standard surveillance using duplex ultrasound (DUS) is resource intensive. Ankle Doppler waveform assessment is quick, inexpensive and accurate for PAD diagnosis, yet its role in postrevascularisation surveillance remains unexplored. This study aims to evaluate the diagnostic accuracy of ankle handheld Doppler waveform assessment (ankle HHD) for detecting restenosis after lower limb revascularisation, as compared with formal DUS.Methods and analysisThis is a prospective diagnostic accuracy study (ClinicalTrials.gov Identifier NCT06619223). We aim to recruit 121 people with PAD undergoing planned lower limb revascularisation at Imperial College Healthcare NHS Trust. Follow-up assessments will take place at 3 months, 6 months and 12 months post revascularisation. At each visit, a vascular scientist will perform the index test (Ankle HHD) followed by DUS as the reference standard. A subset of participants will undergo repeat testing to assess interobserver and intraobserver reliability. Restenosis will be defined as one or more arterial lesions of ≥50% stenosis or tandem lesions with a combined value of ≥50%. The primary outcome is the sensitivity of ankle Doppler waveform assessment for detecting restenosis, compared with DUS.Ethics and disseminationThe study has received approval from Health Research Authority (HRA) and Health and Care Research Wales (REC reference 24/LO/0462). Results will be disseminated through research presentations and papers.Trial registration numberClinicalTrials.gov, NCT06619223.

Objectives To evaluate the feasibility of T1w-3D black-blood turbo spin echo (TSE) sequence with variable flip angles for the diagnosis of thoracic large vessel vasculitis (LVV). Methods Thirty-five patients with LVV, diagnosed according to the current standard of reference, and 35 controls were imaged at 3.0T using 1.2 × 1.3 × 2.0 mm 3 fat-suppressed, T1w-3D, modified Volumetric Isotropic TSE Acquisition (mVISTA) pre- and post-contrast. Applying a navigator and peripheral pulse unit triggering (PPU), the total scan time was 10–12 min. Thoracic aorta and subclavian and pulmonary arteries were evaluated for image quality (IQ), flow artefact intensity, diagnostic confidence, concentric wall thickening and contrast enhancement (CWT, CCE) using a 4-point scale. Results IQ was good in all examinations (3.25 ± 0.72) and good to excellent in 342 of 408 evaluated segments (83.8 %), while 84.1 % showed no or minor flow artefacts. The interobserver reproducibility for the identification of CCE and CWT was 0.969 and 0.971 (p < 0.001) with an average diagnostic confidence of 3.47 ± 0.64. CCE and CWT were strongly correlated (Cohen’s k = 0.87; P < 0.001) and significantly more frequent in the LVV-group (52.8 % vs. 1.0 %; 59.8 % vs. 2.4 %; P < 0.001). Conclusions Navigated fat-suppressed T1w-3D black-blood MRI with PPU-triggering allows diagnosis of thoracic LVV. Key Points • Cross-sectional imaging is frequently applied in the diagnosis of LVV. • Navigated, PPU-triggered, T1w-3D mVISTA pre- and post contrast takes 10–12 min. • In this prospective, single-centre study, T1w-3D mVISTA accurately depicted large thoracic vessels. • T1w-3D mVISTA visualized CWT/CCW as correlates of mural inflammation in LVV. • T1w-3D mVISTA might be an alternative diagnostic tool without ionizing radiation.

Background Stenoses of the outflow tract can compromise the function of arteriovenous fistulas (AVFs) used for haemodialysis. Limited data exists to differentiate stenosis types and understand their underlying causes. This study aims to develop a new classification system for AVF stenoses based on the morphology and location of the lesions as assessed by duplex ultrasound (DUS). Materials and methods A multicenter, cross-sectional cohort study was conducted in four hospitals from October 2017 to February 2024. After exclusions, 1122 patients with dysfunctional AVFs were evaluated. The DUS variables studied were intimal-media thickness (IMT), venous valve calcifications (VVC), and stenosis location. The stenosis location was classified as follows: juxta/post anastomotic tract; middle tract; proximal tract; arm cephalic vein tract; cephalic arch; and arm basilic vein tract. Results Intimal hyperplasia (corresponding to IMT ≥ 0.4 mm) was present in 718 AVFs (64%; 95% CI 0.61–0.67), with an average thickness of 0.72 ± 0.14 mm (95% CI 0.71–0.73); no intimal hyperplasia (corresponding to IMT < ≥≥0.4 mm) in 354 AVFs (32%; 95% CI 0.29–0.34), and valve calcification in 50 AVFs (4%; 95% CI 3–6). Stenoses were classified in 4 types: Type A, dominant IMT with thickness ≥ 0.6 mm; Type B, IMT 0.4 mm to 0.6 mm; Type C, IMT < 0.4 mm; and Type D, with calcifications of the venous valves. Most of the stenosis fell within Type A and C (79.5%). Type A stenosis was in 80% found in the juxta/post-anastomotic segments. The middle and proximal tract segments showed a similar distribution of all four types of stenosis. Type C and D stenosis were prevalent in the distal segments. Conclusion DUS reveals distinct characteristics of AVF stenoses, suggesting different underlying causes. This classification system may facilitate the development of targeted interventions for preventing and treating AVF stenosis. Clinical trial number Not applicable.

PurposeA prospective, multicenter post-market surveillance study in Japan evaluated the 2-year safety and effectiveness of the DES in real-world patients with complex femoropopliteal artery lesions.MethodsThere were no exclusion criteria, and consecutive symptomatic patients with femoropopliteal lesions treated with the DES were enrolled in the study. Clinically driven target lesion revascularization (TLR) was defined as reintervention performed for > 50% diameter stenosis after recurrent clinical symptoms of peripheral arterial disease. Clinical benefit was defined as freedom from persistent or deteriorating ischemic symptoms. Patency was evaluated by duplex ultrasound where physicians considered this standard of care.ResultsIn this study, 905 patients were enrolled at 95 institutions in Japan. There were numerous comorbidities including a high incidence of diabetes (58.8%) and chronic kidney disease (43.6%). Additionally, 21.4% of patients were classified with critical limb ischemia. Lesions were complex, with an average length of 14.6 ± 9.6 cm (range 0.5–40 cm), 41.5% total occlusions, and 18.7% in-stent restenosis. In total, 1861 DES were placed in 1080 lesions. Two-year follow-up was obtained for > 90% of eligible patients. Freedom from TLR was 83.7%, and clinical benefit was 80.0% through 2 years. The 2-year primary patency rate was 70.3%. Rutherford classification significantly improved (p < 0.01), with approximately 80% of patients classified as Rutherford class 0 or 1 at 2 years.ConclusionDespite more challenging lesion characteristics, 2-year results from the current study are similar to outcomes from the previous Zilver PTX studies, confirming the efficacy of the Zilver PTX DES in a complicated femoropopliteal lesion (Zilver PTX Post-Market Study in Japan; NCT02254837).Level of EvidencePost-market surveillance study, Level III.

Atrial fibrillation (AF) and hypertension (HT) often coincide and both are independently associated with endothelial dysfunction. We tested the hypothesis that brachial artery flow‐mediated dilation (FMD), an indicator of endothelial health, will be poorer in AF patients with HT (AF + HT) than AF without concurrent HT. In a cross‐sectional design study, AF (n = 29; mean 70 years; 9 females) and AF + HT (n = 33; 68 years (p = 0.302); 14 females) patients underwent Duplex‐Doppler ultrasound imaging of brachial artery diameter and flow velocity during baseline (2 min), distal tourniquet cuff inflation (5 min), and following cuff deflation (3 min). The peak increase in artery diameter following cuff deflation was taken as FMD and analyzed as absolute, percentage change, FMD and shear‐rate area‐under‐the‐curve (SRAUC; FMD‐to‐SRAUC) ratio, and using SRAUC as a covariate (FMDSRAUC). Body mass index (BMI) was used as an additional covariate for between‐group comparisons of vascular data. Mean arterial pressure was higher in the AF + HT versus the AF group (median [interquartile range] 93 [85–99] vs. 84 [80–90] mm Hg, respectively; p < 0.05). Baseline brachial artery diameters were similar (p > 0.05). FMD was lower in AF + HT than AF patients (3.36 [1.69–5.21] vs. 4.98 [2.96–7.11] %, respectively; p < 0.05). Similar group differences were observed in absolute FMD, FMD‐to‐SRAUC ratio and FMDSRAUC (p < 0.05). AF patients with concurrent HT exhibit poorer endothelium‐dependent vasodilation compared to AF patients, indicating that the presence of comorbid HT exacerbates endothelial dysfunction in AF patients.

To define the specificity and extent of duplex sonography (DS) findings suggestive of vessel wall inflammation in patients with giant cell arteritis (GCA). Patients admitted between December 2006 and April 2009 to the University Hospital Basel with a suspicion of GCA were eligible for the study. DS of 2x11 arterial regions was performed in all study participants, and American College of Rheumatology criteria were applied to classify patients into GCA or non-GCA groups. GCA was diagnosed in 38 of the 72 participants (53%). A DS pattern suggestive of vessel wall inflammation was not observed in any of the patients in the non-GCA group but, in 21 of the 38 patients with GCA (55%), DS signs suggestive of vessel wall inflammation of > or =1 vessel region were detected. In 12 of the 38 patients with GCA (32%), DS signs of large vessel vasculitis (LVV) were found in > or =1 vessel region(s) of both upper and lower limb vessels. Follow-up DS was performed 6 months after the baseline examination in 9 of the 12 patients with LVV and showed the persistence of most findings despite normalised signs of systemic inflammation. DS detects changes in the vessel wall that appear to be specific for GCA; they can be present in upper and lower limb arteries of patients with GCA. Surprisingly, DS-detectable LVV and signs of systemic inflammation are largely dissociated.

Purpose To report the 3-year results of the MAJESTIC first-in-human study of the Eluvia Drug-Eluting Vascular Stent System for treating femoropopliteal artery lesions. Methods The prospective, single-arm, multicenter clinical trial enrolled 57 patients with symptomatic lower limb ischemia (Rutherford category 2, 3, or 4) and lesions in the superficial femoral artery or proximal popliteal artery. Mean lesion length was 70.8 ± 28.1 mm, and 46% of lesions were occluded. Efficacy measures at 2 years included primary patency, defined as duplex ultrasound peak systolic velocity ratio of ≤2.5 and the absence of target lesion revascularization (TLR) or bypass. Safety monitoring through 3 years included adverse events and TLR. Results Primary patency was estimated as 83.5% (Kaplan–Meier analysis) at 24 months, and 90.6% (48/53) of patients maintained an improvement in Rutherford class. At 36 months, the Kaplan–Meier estimate of freedom from TLR was 85.3%. No stent fractures were identified, and no major target limb amputations occurred. Conclusion MAJESTIC results demonstrated long-term treatment durability among patients whose femoropopliteal arteries were treated with the paclitaxel-eluting Eluvia stent. Level of Evidence Level 2b, cohort study

Superficial venous thrombosis (SVT) is a fairly common disorder, characterized by the formation of thrombi inside superficial veins, with or without an associated inflammatory reaction. Its evolution is frequently self-limited. However, serious complications may change this clinical course with extension to deep vein thrombosis (DVT) and pulmonary embolism (PE). SVT shares similar risk factors with DVT and is frequently associated with the presence of varicose veins. However, the occurrence of non-varicose veins could conceal risk factors such as malignancies, thrombophilia, or Buerger’s disease. While the clinical diagnosis is generally straightforward, additional diagnostic evaluations are often necessary. Duplex ultrasound (DUS) is an invaluable tool that provides the location of SVT, the proximity to the sapheno–femoral junction, and the clot length, all of which influence the decision for optimal management. The treatment of SVT should be symptomatic, pathogenic (limiting the extension of thrombosis), and prognostic (to prevent complications). There are several guidelines that provide recommendations, and despite the need for more consensus and for further studies, the treatment of SVT should be mainly medical, including anticoagulation in specific clinical situations and symptom relief, with invasive treatment in a minority of cases. Initiation, intensity, and length of anticoagulant treatment should be based on the eventual risk of progression to DVT or PE, which can be high, intermediate, or low, based on the location of SVT and the clot length. Our review summarizes the evaluation and proper management of SVT and highlights the importance of a shared decision within the heart team regarding this condition in order to prevent further complications.

IntroductionEndovascular therapy is the main treatment for chronic limb-threatening ischaemia in the UK. Despite a restenosis risk of 50% over 2 years, reintervention rates are low, potentially resulting in preventable amputations. European guidelines recommend ultrasound surveillance to facilitate early treatment of restenosis. This study will investigate the use of duplex ultrasound after endo revascularisation (DUSTER). The aim is to assess the feasibility, acceptability and impact on clinical decision-making of a 1-year integrated ultrasound surveillance programme after lower limb endovascular therapy.Methods and analysisDUSTER is a mixed-methods study. Phase I is a three-site, feasibility, open-label, randomised controlled trial. The standard of care, the control arm, is standard clinical surveillance by a vascular specialist at 1, 6 and 12 months. The intervention arm will receive integrated ultrasound (ankle-brachial pressure index, toe pressure and duplex) plus standard clinical surveillance. Primary outcomes are rates of attendance and completion of ultrasound surveillance tests, as well as the percentage of participants undergoing reintervention for restenosis. Secondary outcomes are limb salvage, amputation-free survival, reasons for amputation, complications, serious adverse events and mortality.Phase II comprises independent semistructured interviews with intervention arm participants. The interviews will explore barriers and facilitators to ultrasound surveillance and the effect of ultrasound surveillance on patients’ lives.Phase III has two separate focus groups for participants and clinical stakeholders to identify which outcomes matter most in any subsequent large-scale effectiveness trials.Ethics and disseminationThis research has been approved by a UK (West Midlands, Black Country) Research Ethics Committee (reference 24/WM/0232) and the Health Research Authority (IRAS 349192). Dissemination of results will be by the DUSTER co-investigators in peer-reviewed journals, to the National Institute for Health and Care Research and to a lay audience via the Mid and South Essex NHS Foundations Trust website.Trial registration number NCT06702306.