Study protocol for a comparative diagnostic accuracy study of bedside tests used to detect arterial disease in diabetes: TEsting for Arterial disease in Diabetes (TrEAD) study.

INTRODUCTION: In the UK, over 7000 amputations are performed each year because of diabetes. Up to 80% of these are preceded by a foot ulcer and could therefore be prevented with improvements in ulcer care. Peripheral arterial disease is an important risk factor for the development of diabetic foot ulceration. However, its diagnosis in diabetes is challenging due to the presence of neuropathy and arterial calcification. Commonly used bedside tests either have low sensitivities or little supporting evidence to justify their use. Duplex ultrasound (DUS) has good correlation to angiography findings but a full scan is difficult to learn and time consuming to perform. We have previously demonstrated that a focused DUS of the distal anterior and posterior tibial arteries at the ankle (podiatry ankle duplex scan (PAD-scan)) can be readily learnt by novices and performed rapidly and accurately. The primary aim of this study is to determine the diagnostic accuracy of the PAD-scan and other commonly used bedside tests in detecting arterial disease in diabetes. METHODS AND ANALYSIS: The study will include 305 patients presenting to diabetic foot clinics at two centres. Arterial assessment will be performed using the following index tests: the PAD-scan, pulse palpation, audible handheld Doppler, Ankle Brachial Pressure Index, Toe Brachial Pressure Index and transcutaneous pressure of oxygen. Patients will then undergo a full lower limb arterial DUS by a blinded vascular scientist as a reference test. ETHICS AND DISSEMINATION: Approval was gained from NRES Committee London (REC reference 17/LO/1447). Findings will be disseminated by various methods including international presentations and publication in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT04058626).

An investigation of the detection capability of pulsed wave duplex Doppler of low grade stenosis using ultrasound contrast agent microbubbles - An in-vitro study.

OBJECTIVE: The objective of the study was to investigate whether clinically used ultrasonic contrast agents improved the accuracy of spectral Doppler ultrasound in the detection of low grade (<50%) renal artery stenosis. Low grade stenoses in the renal artery are notoriously difficult to reliably detect using Doppler ultrasound due to difficulties such as overlying fat and bowel gas. METHODS: A range of anatomically-realistic renal artery phantoms with varying low degrees of stenosis (0, 30 and 50%) were constructed and peak velocity data was measured from within the pre-stenotic and mid-stenotic regions in each phantom, for both unenhanced and contrast-enhanced spectral Doppler data acquisitions. The effect of a 20 mm overlying fat layer on the ultrasound beam distortion and phase aberration, and hence on the measured peak velocity data, was also investigated. RESULTS: The overlying fat layer produced a statistically significant underestimation (p < 0.01) in both the peak velocity and peak velocity ratio [Stenotic Region(Vmax)/Pre-stenotic Region(Vmax)] for the 0% and 30% stenosis models, but not the 50% model. A statistically significant increase (p < 0.01) in the peak velocity was found in the contrast-enhanced Doppler spectra; however, no significant difference was found between the unenhanced and contrast enhanced peak velocity ratio data, which suggests that the ratio metric has better diagnostic accuracy. The peak velocity ratios determined for each of the contrast-enhanced phantoms correctly predicted if the phantom had a stenosis and furthermore correctly classified the degree of stenosis. CONCLUSION: Contrast-enhanced Doppler ultrasound could significantly assist in the early detection of renal artery disease.

[Quality standards for ultrasonographic assessment of peripheral vascular malformations and vascular tumors. Report of the french society for vascular medicine. 2018 Update]. / Standards de qualité pour la pratique de l'examen écho-Doppler dans l'étude des malformations et tumeurs vasculaires. Rapport de la Société française de médecine vasculaire (SFMV) : actualisation 2018.

The quality standards of the French Society of Vascular Medicine for the ultrasonographic assessment of vascular malformations are based on the two following requirements: (1) technical know-how: mastering the use of ultrasound devices and the method of examination; (2) medical know-how: ability to adapt the methods and scope of the examination to its clinical indication and purpose, and to rationally analyze and interpret its results. AIMS OF THE QUALITY STANDARDS: To describe an optimal method of examination in relation to the clinical question and hypothesis. To homogenize practice, methods, glossary, and reporting. To provide good practice reference points, and promote a quality process. ITEMS OF THE QUALITY STANDARDS: The 3 levels of examination; their clinical indications and goals. The reference standard examination (level 2), its variants according to clinical needs. The minimal content of the examination report; the letter to the referring physician (synthesis, conclusion and proposal for further investigation and/or therapeutic management). Commented glossary (anatomy, hemodynamics, semiology). Technical bases. Setting and use of ultrasound devices. Here, we discuss ultrasonography methods of using of ultrasonography for the assessment of peripheral vascular malformations and tumors (limbs, face, trunk).

Imaging of high-risk carotid plaques: ultrasound.

Duplex ultrasonography has a well-established role in the assessment of the degree of stenosis caused by carotid atherosclerosis. This assessment is derived from Doppler velocity changes induced by the narrowing lumen of the artery. New research into the mechanisms for plaque rupture and atheroembolic stroke indicates that the degree of narrowing is an imperfect predictor of stroke risk, and that other factors, such as plaque composition and remodeling and biomechanical forces acting on the plaque, can play a role. New advances in ultrasound imaging technology have made it possible to investigate these measures of plaque vulnerability to identify pre-embolic unstable carotid plaques. Efforts have been made to quantify the morphologic appearance of the plaque in B-mode images and to correlate them with histology. Additional research has resulted in the first generation of clinically available 3-dimensional ultrasound transducers that reduce operator-dependence and variability. Finally, ultrasonography provides real-time imaging and physiologic information that can be utilized to measure disruptive forces acting on carotid plaques. We review some of these exciting developments in ultrasonography and discuss how these may impact clinical practice.

Eco Johiliss (GEC-E). Prueba simplificada para diagnóstico de estenosis carotídea mediante ecografía doppler / Echo Johiliss (CSG-U). Simplified diagnostic test for carotid stenosis using doppler ultrasound

INTRODUCCIÓN: El eco Johiliss/gradación de estenosis carotídea mediante ecografía (EJ/GEC-E) es una prueba rápida y económica para diagnóstico de estenosis carotídea, diseñada para cribado. El EJ emplea ecografía doppler utilizando para la valoración una tabla simplificada que evalúa 2 parámetros: velocidad en la carótida interna y ratio de velocidad entre la carótida interna y común, apoyados en la presencia de placas de ateroma. El EJ puede ser realizado por un enfermero con certificación para el uso de ecógrafo doppler. Mediante EJ el paciente se clasificará en 4 posibles grupos que determinarán sus necesidades de seguimiento. OBJETIVOS: Validar esta nueva prueba diagnóstica y determinar el tiempo necesario para su realización. MATERIAL Y MÉTODOS: Se realizaron 2 estudios complementarios: un estudio retrospectivo para determinar la validez de EJ según los resultados verificados de 265 estudios de troncos supraaórticos y un estudio prospectivo con 76 pacientes para la determinación del tiempo necesario para la prueba. Se utilizó el software estadístico «R» con el paquete «Rcmdr». RESULTADOS: Se obtienen los siguientes valores para EJ, con IC al 95%: sensibilidad 0,817 (0,737-0,877); especificidad 0,993 (0,963-0,999); VPP 98,9% (94,3-99,8%); VPN 87,6% (81,9-91,8%), tiempo necesario para la prueba 4 min 33 s (4:23-6:02). El sobrepeso no afecta significativamente al tiempo de realización de la prueba (p = 0,4238) y la ausencia de lesiones o cicatrices lo reduce (p = 0,0019). CONCLUSIONES: La EJ es una prueba diagnóstica eficaz para cribado de pacientes

INTRODUCTION: Echo Johiliss (EJ) Carotid Stenosis Grading by Ultrasound (CSG-U) is a quick, inexpensive diagnostic test for carotid stenosis, designed for screening. EJ uses doppler ultrasound with a simplified chart that tests 2 parameters: Speed in the internal carotid and speed ratio between the internal and common carotids, supported by the presence of atheroma plaques. EJ can be performed by a nurse qualified to use doppler ultrasound. By means of EJ, patients will be classified into 4 possible groups, which will determine their needs of medical follow up. OBJECTIVES: To validate this new diagnostic test and to determine its execution time. MATERIAL AND METHODS: Two complementary studies were made: A retrospective study, in order to determine the validity of EJ according to the verified results of 265 studies of supra-aortic trunks, and a prospective study with 76 patients for the determination of the time needed for the test. The statistical software «R» with the «Rcmdr» package was used. RESULTS: The following values for EJ, with 95% CI were obtained: Sensitivity 0.817 (0.737-0.877), specificity 0.993 (0.963-0.999), PPV 98.9% (94.3-99.8%) NPV 87.6% (81.9-91.8%), execution time, 4 min 33 s (4:23-6:02). Overweight did not significantly affect the time needed for the test (P=.4238) and the absence of lesions or scars reduces it (P=.0019). CONCLUSION: EJ is an effective diagnostic test for patient screening

Propuesta de optimización del estudio ecográfico venoso de extremidades inferiores de acuerdo con el método LEAN / Proposal for optimising lower limb venous duplex ultrasound evaluation according to the LEAN method

INTRODUCCIÓN: En todo proceso diagnóstico y terapéutico, y más en tiempo de importantes recortes sanitarios, es imprescindible buscar la máxima eficiencia. El método LEAN intenta optimizar todo proceso productivo y proponemos su aplicación para el estudio ecográfico venoso de extremidades inferiores. MATERIAL Y MÉTODOS: Se incluyó a pacientes con sintomatología de insuficiencia venosa, varices visibles y sin intervenciones previas ni afectación profunda y se les realizó un eco-Doppler estandarizado según normas del CDVNI. Se valoraron el punto de fuga, el recorrido, el punto de reentrada y el sistema venoso profundo. Se determinaron los puntos mínimos de estudio ecográfico (puntos LEAN) necesarios para una correcta evaluación diagnóstica y se construyó un algoritmo de decisión eficiente. RESULTADOS: Entre los años 2007-2012 se realizó un estudio transversal de 984 ecografías venosas de extremidad inferior. El 96% de los pacientes presentaron un punto de fuga y recorrido correctamente determinados al insonar ingle (LEAN-1) y hueco poplíteo (LEAN-2) y, de estos, un 3,6% presentaban un segundo punto de fuga, no detectado en estas localizaciones. Un 4,2% de los pacientes no presentó ningún punto de fuga en LEAN-1 o LEAN-2, tratándose de perforantes en muslo (50%), pierna (30%) y Hunter (20%). CONCLUSIONES: La exclusiva insonación de los puntos LEAN-1 y LEAN-2 nos permiten realizar un diagnóstico certero y suficiente en el 92,4% de los pacientes, optimizando de esta manera el tiempo y el coste de la exploración. Siguiendo el algoritmo propuesto, solo un 4,2% de los pacientes precisará una exploración venosa completa

INTRODUCTION: It is essential to look for maximal efficiency in all diagnostic and therapeutic procedures, and especially in times of health budget cuts. The LEAN method tries to optimise all production procedures, and its application is proposed in the lower limb venous duplex ultrasound study. MATERIALS AND METHODS: Patients suffering from venous insufficiency (VI), external varicose veins, and without previous venous surgery or deep vein thrombosis were included and a duplex ultrasound evaluation was performed according to the recommendations for non-invasive vascular diagnosis. Deep venous system, shunt type, trajectory and drainage were evaluated. The minimum number of ultrasound evaluation points needed for a correct diagnosis was determined (LEAN points), and an efficient decision-making algorithm was developed. RESULTS: A descriptive, cross-sectional study was conducted on 984 lower limb venous ultrasound evaluations performed between 2007 and 2012. Almost all (96%) patients had a shunt and trajectory correctly evaluated by groin ultrasound evaluation (LEAN-1), and popliteal area ultrasound evaluation (LEAN-2). Only 3.6% of these patients showed a secondary shunt that was not located in LEAN points. Another 4.2% of patients did not show any shunt in LEAN-1 or LEAN-2, being due to thigh perforating veins (50%), leg perforating veins (30%), or Hunter perforating veins (20%). CONCLUSIONS: The duplex ultrasound evaluation of LEAN-1 and LEAN-2 points allows us to reach a complete diagnosis for VI in 92.4% of patients, thus reducing evaluation time and costs. According to the proposed algorithm, only 4.2% of patients would need a complete venous ultrasound evaluation to reach the correct diagnosis

Estudio de la insuficiencia venosa crónica mediante ecografía Doppler y realización de cartografía venosa / Doppler ultrasound study and venous mapping in chronic venous insufficiency

La insuficiencia venosa crónica (IVC) de las extremidades inferiores es una enfermedad muy prevalente. La ecografía Doppler se ha establecido en las últimas décadas como el método de elección en el estudio de esta patología, por lo que resulta imprescindible ante una eventual indicación quirúrgica. El objetivo de este trabajo es establecer una metodología en la exploración, incluyendo la realización de cartografía y el marcaje prequirúrgico. Para ello revisaremos la anatomía venosa de los miembros inferiores y la fisiopatología de la IVC explicando los conceptos hemodinámicos básicos y la terminología necesarios para la realización de un informe radiológico que permita una adecuada planificación terapéutica y comunicación con otros especialistas. Explicaremos brevemente la estrategia CHIVA (cura hemodinámica de la insuficiencia venosa ambulatoria), método quirúrgico mínimamente invasivo que tiene como objetivo restaurar la hemodinámica venosa sin extirpar la vena safena (AU)

Chronic venous insufficiency of the lower limbs is very prevalent. In recent decades, Doppler ultrasound has become the method of choice to study this condition, and it is considered essential when surgery is indicated. This article aims to establish a method for the examination, including venous mapping and preoperative marking. To this end, we review the venous anatomy of the lower limbs and the pathophysiology of chronic venous insufficiency and explain the basic hemodynamic concepts and the terminology required to elaborate a radiological report that will enable appropriate treatment planning and communication with other specialists. We briefly explain the CHIVA (the acronym for the French term "cure conservatrice et hémodynamique de l'insuffisance veineuse en ambulatoire" = conservative hemodynamic treatment for chronic venous insufficiency) strategy, a minimally invasive surgical strategy that aims to restore correct venous hemodynamics without resecting the saphenous vein (AU)

Ultrasound tagged near infrared spectroscopy does not detect hyperventilation-induced reduction in cerebral blood flow.

INTRODUCTION: Continuous non-invasive monitoring of cerebral blood flow (CBF) may be important during anaesthesia and several options are available. We evaluated the CerOx monitor that employs ultrasound tagged near infrared spectroscopy to estimate changes in a CBF index (CFI). METHODS: Seven healthy males (age 21-26 years) hyperventilated and were administered phenylephrine to increase mean arterial pressure by 20-30 mmHg. Frontal lobe tissue oxygenation (ScO2) and CFI were obtained using the CerOx and mean blood flow velocity in the middle cerebral artery (MCAv mean) was determined by transcranial Doppler. Blood flow in the internal and external carotid artery (ICAf and ECAf) was determined using duplex ultrasonography and forehead skin blood flow (SkBF) and oxygenation (S skin O2) by laser Doppler and white light spectroscopy. RESULTS: During hyperventilation MCAv mean and ICAf decreased by 44% (median; interquartile range 40-49; p = 0.016) and 46% (40-53; p = 0.03), respectively. Conversely, CFI increased by 9% (2-31; p = 0.016), while no significant change was observed in ScO2. SkBF increased by 19% (9-53; p = 0.016) and S skin O2 by 6% (1-7; p = 0.047), although ECAf was unchanged. Administration of phenylephrine was not associated with any changes in MCAv mean, ICAf, ECAf, ScO2, SkBF, S skin O2, or CFI. CONCLUSION: The CerOx was able to detect a stable CBF during administration of phenylephrine. However, during hyperventilation MCAv mean and ICAf decreased while CFI increased, likely due to an increase in superficial tissue oxygenation. Thus, CFI does not provide an unbiased evaluation of changes in CBF.

Diagnostic ultrasonography for peripheral vascular emergencies.

Over the past decade, emergency and critical care physicians have been empowered with the ability to use bedside ultrasonography to assist in the evaluation and management of a variety of emergent conditions. Today a single health care provider at the bedside with Duplex ultrasound technology can evaluate peripheral vascular calamities that once required significant time and a variety of health care personnel for the diagnosis. This article highlights peripheral thromboembolic disease, aneurysm, pseudoaneurysm, and arterial occlusion in the acute care setting.

Denoising performance of modified dual-tree complex wavelet transform for processing quadrature embolic Doppler signals.

Quadrature signals are dual-channel signals obtained from the systems employing quadrature demodulation. Embolic Doppler ultrasound signals obtained from stroke-prone patients by using Doppler ultrasound systems are quadrature signals caused by emboli, which are particles bigger than red blood cells within circulatory system. Detection of emboli is an important step in diagnosing stroke. Most widely used parameter in detection of emboli is embolic signal-to-background signal ratio. Therefore, in order to increase this ratio, denoising techniques are employed in detection systems. Discrete wavelet transform has been used for denoising of embolic signals, but it lacks shift invariance property. Instead, dual-tree complex wavelet transform having near-shift invariance property can be used. However, it is computationally expensive as two wavelet trees are required. Recently proposed modified dual-tree complex wavelet transform, which reduces the computational complexity, can also be used. In this study, the denoising performance of this method is extensively evaluated and compared with the others by using simulated and real quadrature signals. The quantitative results demonstrated that the modified dual-tree-complex-wavelet-transform-based denoising outperforms the conventional discrete wavelet transform with the same level of computational complexity and exhibits almost equal performance to the dual-tree complex wavelet transform with almost half computational cost.

Note: Comparative experimental studies on the performance of 2-2 piezocomposite for medical ultrasound transducers.

The paper reports the experimental investigation of the behavior of 2-2 Lead Zirconate Titanate (PZT)-polymer composite transducers array for clinical ultrasound equipments. Several 2-2 plate composites having the same dicing pitch of 0.11 mm and different volume fractions were manufactured and investigated. Measurements were performed through different techniques such as electrical impedance, pulse-echo, and Laser Doppler Vibrometer. With the last one, maps of the surface displacement were presented relative to thickness mode and first lateral mode resonance frequencies. The transducers with volume fractions of the 40% resulted markedly inefficient, whereas the largest bandwidth and best band shape were achieved by the 50%.

Mechanochemical endovenous ablation of small saphenous vein insufficiency using the ClariVein(®) device: one-year results of a prospective series.

OBJECTIVE: This study evaluated the feasibility, safety and 1-year results of mechanochemical endovenous ablation (MOCA™) of small saphenous vein (SSV) insufficiency. DESIGN: Prospective cohort study. MATERIALS AND METHODS: Fifty consecutive patients were treated for primary SSV insufficiency with MOCA™ using the ClariVein(®) device and polidocanol. Initial technical success, complications, patient satisfaction and visual analogue scale (VAS) pain score were assessed. Anatomic and clinical success was assessed at 6 weeks and at 1 year. RESULTS: Initial technical success of MOCA™ was 100%. At the 6-week assessment, all treated veins were occluded. The 1-year follow-up duplex showed anatomic success in 94% (95% confidence interval, 0.87-1). Venous clinical severity score (VCSS) decreased significantly from 3.0 (interquartile range (IQR) 2-5) before treatment to 1.0 (IQR 1-3, P < 0.001) at 6 weeks and to 1.0 (IQR 1-2, P < 0.001) at 1 year. Median procedural VAS score for pain was 2 (IQR 2-4). No major complications were observed, especially no nerve injury. CONCLUSIONS: MOCA™ is a safe, feasible and efficacious technique for treatment of SSV insufficiency. One-year follow-up shows a 94% anatomic success rate and no major complications.

Morphological features of the internal carotid artery: advantages of combining linear and convex probes in duplex ultrasonography.

RATIONALE AND OBJECTIVES: Previous research has determined that carotid abnormalities (CAs) are partly located >3 cm above the carotid bifurcation. However, identifying CAs occurring in this location using high-frequency linear probes is difficult. The aim of this study was to explore the efficacy of a combination of high-frequency and low-frequency probes in duplex ultrasonography for identifying morphologic features of the internal carotid artery (ICA). MATERIALS AND METHODS: A total of 1055 ICAs from 532 patients were analyzed. CAs were classified prospectively according to the criteria of Wain et al, Weibel and Fields, and Metz et al. The diagnostic rates of high-frequency ultrasonography alone and a combination of high-frequency and low-frequency ultrasonography were compared. The distances from the carotid bifurcation to the initial point of the CA and to the mandibular angle were also measured. RESULTS: High-frequency ultrasonography detected 23.2% of CAs, and the combination detected 32.2% of CAs (P < .001) in the 1055 ICAs. Of these CAs, 32.4% and 16.8% began >2.5 and >3 cm above the carotid bifurcation, respectively. The distance between the carotid bifurcation and the mandibular angle was <1.5 cm in 100 arteries (9.48%). The diameter of the distal ICA was larger in patients with CAs than in those without CAs (4.33 ± 0.52 vs 4.13 ± 0.49 mm, P < .001). CONCLUSIONS: Combining high-frequency and low-frequency probes is better than high-frequency probes alone to assess morphologic features of the ICA in duplex ultrasonography. Low-frequency convex probes should be added to traditional ultrasonography for the evaluation of morphologic features of the ICA before carotid endarterectomy, carotid artery stenting, and CA angioplasty.

Accuracy of emergency physician-performed ultrasonography in the diagnosis of deep-vein thrombosis: a systematic review and meta-analysis.

Duplex ultrasound is the first-line diagnostic test for detecting lower limb deep-vein thrombosis (DVT) but it is time consuming, requires patient transport, and cannot be interpreted by most physicians. The accuracy of emergency physician-performed ultrasound (EPPU) for the diagnosis of DVT, when performed at the bedside, is unclear. We did a systematic review and meta-analysis of the literature, aiming to provide reliable data on the accuracy of EPPU in the diagnosis of DVT. The MEDLINE and EMBASE databases (up to August 2012) were systematically searched for studies evaluating the accuracy of EPPU compared to either colour-flow duplex ultrasound performed by a radiology department or vascular laboratory, or to angiography, in the diagnosis of DVT. Weighted mean sensitivity and specificity and associated 95% confidence intervals (CIs) were calculated using a bivariate random-effects regression approach. There were 16 studies included, with 2,379 patients. The pooled prevalence of DVT was 23.1% (498 in 2,379 patients), ranging from 7.4% to 47.3%. Using the bivariate approach, the weighted mean sensitivity of EPPU compared to the reference imaging test was 96.1% (95%CI 90.6-98.5%), and with a weighted mean specificity of 96.8% (95%CI:94.6-98.1%). Our findings suggest that EPPU may be useful in the management of patients with suspected DVT. Future prospective studies are warranted to confirm these findings.

Impact of portable duplex ultrasonography in head and neck reconstruction.

We have reviewed the use of portable duplex ultrasonography (PDU) in 12 patients who underwent soft tissue/bone head and neck reconstruction, aiming to determine its role in the design and management of such complex cases. According to our data, there were modifications either of the surgical plan or of patient's management, based on PDU findings, in 9 (75%) of 12 patients. The use of ultrasound directed to subtle modifications in 3 patients (25%) but to significant changes of the surgical plan in the other 3 patients (25%). Also, the use of duplex ultrasound impacted significantly the postoperative management in 4 patients (33.33%). Thus, significant impact of PDU in patient's treatment was recorded in 58.33% of cases. Portable ultrasound represents generally available method for preoperative, intraoperative, and postoperative diagnosis and decision making in free tissue transfer, hence could replace in the future the unidirectional Doppler in the hands of head and neck surgeons.

The Leipzig prospective vascular ultrasound registry in radial artery catheterization: impact of sheath size on vascular complications.

OBJECTIVES: This study investigated the impact of sheath size on the rate of radial artery occlusions (RAO) (primary objective) and other access site complications (hemorrhage, pseudoaneurysm, arteriovenous fistula) as secondary objectives after transradial coronary catheterization. BACKGROUND: The number of vascular access complications in the published data ranges from 5% to 38% after transradial catheterization. METHODS: Between November 2009 and August 2010, 455 patients 65.3 ± 10.9 years of age (62.2% male) with transradial access with 5-F (n = 153) or 6-F (n = 302) arterial sheaths were prospectively recruited. Duplex sonography was obtained in each patient before discharge. Patients with symptomatic RAO were treated with low-molecular-weight heparin (LMWH), and a follow-up was performed. RESULTS: The incidence of access site complications was 14.4% with 5-F sheaths compared with 33.1% with 6-F sheaths (p < 0.001). Radial artery occlusion occurred in 13.7% with 5-F sheaths compared with 30.5% with 6-F sheaths (p < 0.001). There was no difference between groups with regard to hemorrhage, pseudoaneurysms, or arteriovenous fistulas. Female sex, larger sheath size, peripheral arterial occlusive disease, and younger age independently predicted RAO in multivariate analysis. In total, 42.5% of patients with RAO were immediately symptomatic; another 7% became symptomatic within a mean of 4 days. Of patients with RAO, 59% were treated with LMWH. The recanalization rates were significantly higher in patients receiving LMWH compared with conventional therapy (55.6% vs. 13.5%, p < 0.001) after a mean of 14 days. CONCLUSIONS: The incidence of RAO by vascular ultrasound was higher than expected from previous data, especially in patients who underwent the procedure with larger sheaths.