Phoenix, AZ, United States
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Schaberle W.,Vascular | Leyerer L.,Vascular | Schierling W.,University of Regensburg | Pfister K.,University of Regensburg
Gefasschirurgie | Year: 2016

Background and purpose: As a non-invasive, side effect-free and cost-effective method, ultrasonography represents the method of choice for the diagnosis of renal artery stenosis. Four different criteria in total, including two direct criteria in peak systolic velocity (PSV) and renal aortic ratio (RAR) and two indirect criteria in resistance index (RI) and acceleration time (AT) for the measurement of relevant renal artery stenosis are described, each demonstrating highly variable accuracy in studies. Furthermore, there is controversy over the degree beyond which stenosis becomes therapeutically relevant and which ultrasound PSV is diagnostically relevant in terms of stenosis grading. Material and methods: This article gives a critical review based on a selective literature search on measurement methodology and the validity of ultrasound in renal artery stenosis. A critical evaluation of methods and a presentation of measurement principles to establish the most precise measurement method possible compared with the gold standard angiography, as well as an evaluation of the importance of computed tomography angiography (CTA) and magnetic resonance angiography (MRA). Results and conclusions: The PSV provides high sensitivity and specificity as a direct measurement method in stenosis detection and grading. Most studies found sensitivities and specificities of 85–90 % for > 50 % stenosis at a PSV > 180–200 cm/s in ROC curve analysis. Other methods, such as the ratio of the PSV in the aorta to the PSV in the renal artery (RAR) or indirect criteria, such as side to side differences in RI (dRI) or AT can be additionally used to improve accuracy. Contrast-enhanced ultrasound improves accuracy by means of echo contrast enhancement. Although in the past only high-grade stenosis was considered relevant for treatment, a drop in pressure of > 20 mmHg in > 50 % stenosis (PSV 180 cm/s) is classified as relevant for increased renin secretion. Stenosis in fibromuscular dysplasia can be reliably graded according to the continuity equation. Although the available studies on the grading of in-stent restenosis are the subject of controversy, there is a tendency to assume higher cut-off values for PSV and RAR. Whilst MRA and CTA demonstrate an accuracy of > 90 %, this is at the cost of possible side effects for patients, particularly in the case of pre-existing renal parenchymal damage. © 2015, The Author(s).

Cheng D.,London Health Sciences Center | Martin J.,London Health Sciences Center | Shennib H.,Vascular | Dunning J.,James Cook University | And 5 more authors.
Journal of the American College of Cardiology | Year: 2010

Objectives: The purpose of this study was to determine whether thoracic endovascular aortic repair (TEVAR) reduces death and morbidity compared with open surgical repair for descending thoracic aortic disease. Background: The role of TEVAR versus open surgery remains unclear. Metaregression can be used to maximally inform adoption of new technologies by utilizing evidence from existing trials. Methods: Data from comparative studies of TEVAR versus open repair of the descending aorta were combined through meta-analysis. Metaregression was performed to account for baseline risk factor imbalances, study design, and thoracic pathology. Due to significant heterogeneity, registry data were analyzed separately from comparative studies. Results: Forty-two nonrandomized studies involving 5,888 patients were included (38 comparative studies, 4 registries). Patient characteristics were balanced except for age, as TEVAR patients were usually older than open surgery patients (p = 0.001). Registry data suggested overall perioperative complications were reduced. In comparative studies, all-cause mortality at 30 days (odds ratio [OR]: 0.44, 95% confidence interval [CI]: 0.33 to 0.59) and paraplegia (OR: 0.42, 95% CI: 0.28 to 0.63) were reduced for TEVAR versus open surgery. In addition, cardiac complications, transfusions, reoperation for bleeding, renal dysfunction, pneumonia, and length of stay were reduced. There was no significant difference in stroke, myocardial infarction, aortic reintervention, and mortality beyond 1 year. Metaregression to adjust for age imbalance, study design, and pathology did not materially change the results. Conclusions: Current data from nonrandomized studies suggest that TEVAR may reduce early death, paraplegia, renal insufficiency, transfusions, reoperation for bleeding, cardiac complications, pneumonia, and length of stay compared with open surgery. Sustained benefits on survival have not been proven. © 2010 American College of Cardiology Foundation.

Schaberle W.,Vascular
Ultrasonography in Vascular Diagnosis: A Therapy-Oriented Textbook and Atlas: Second Edition | Year: 2011

This is the second edition of a well-received book that has been recommended for inclusion in any vascular library or vascular radiology suite. The first edition has been fully revised so as to provide a comprehensive, up-to-date account of vascular ultrasound that reflects recent exciting advances in this diagnostic modality. The emphasis remains on the clinical aspects most relevant to angiologists and vascular surgeons. The main chapters are subdivided into a text section and an atlas section. The text part of each chapter documents the ultrasound anatomy of the vascular territory in question, explains the examination procedure, describes normal and pathological findings, specifies the indications for diagnostic ultrasound, and assesses the clinical impact of the ultrasound findings. The atlas part of each chapter presents a compilation of pertinent case material to illustrate the typical ultrasound findings for both the more common vascular diseases and rarer conditions that are nevertheless significant for the vascular surgeon and angiologist. Throughout, the ultrasound material is compared with the angiographic and intraoperative findings. Beginners will find this a useful textbook that guides them from a sensible and efficient examination procedure to reliable interpretation of ultrasound findings on the basis of a thorough discussion of all relevant vascular diseases. Experienced sonographers will benefit from the comprehensive presentation of rare vascular diseases, the detailed evaluation of the role of ultrasound as compared with other modalities, and the discussion of the ultrasound findings in their clinical context. © Springer-Verlag Berlin Heidelberg 2005 and 2011. All rights are reserved.

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