ABC | Volume 112, Nº6, June 2019

Statement Vascular Ultrasound Statement from the Department of Cardiovascular Imaging of the Brazilian Society of Cardiology – 2019 Arq Bras Cardiol. 2019; 112(6):809-849 Figure 7 – Extracranial segments of the vertebral artery (V0-V3). Table 8 – Cut-off velocity values for proximal vertebral artery stenosis Stenosis < 50% 50 to 69% 70 to 99% V max ≥ 85 cm/s ≥ 140 cm/s ≥ 210 cm/s VVR ≥ 1.3 ≥ 2.1 ≥ 4 EDV ≥ 27 cm/s ≥ 35 cm/s ≥ 55 cm/s VVR: maximum velocity rate at the stenosis site and the V2 segment; EDV: end-diastolic velocity. the mean diameter of the infrarenal aorta is approximately 2.0 cm, with upper normal limit < 3.0 cm. Thus, abdominal aortic aneurysm (AAA) is defined as an aorta that measures > 3.0 cm. AAAs are located between the diaphragm and the aortic bifurcation and can be classified as suprarenal, juxtarenal, and infrarenal. Approximately 85% of AAAs are infrarenal, and 5% involve the suprarenal aorta. 31 About 25% of patients with AAA have associated iliac artery aneurysm. 2 Aneurysms can be fusiform, saccular, or with eccentric shapes. The type of asymmetry can significantly influence the risk of rupture and, as aneurysms grow, they can form laminated thrombi that preserve the arterial lumen. 2 VUS is the most used examination to screen and diagnose asymptomatic patients in emergency units without a prior diagnosis and symptomatic ones. Computed tomography angiography (CTA) is the examination of choice for pre- and postoperative assessment; however, VUS does not lose its value for being more accessible, costing less, and not using nephrotoxic contrast. The current availability of microbubble contrast makes VUS quite attractive, particularly in postoperative assessments. 32 3.1.2. Clinical Indications 2 • Screening (Table 9). • Follow-up: monitor the growth and determine the appropriate time for surgery. 33 • Evaluation of pulsating abdominal mass, signs of rupture, or growth. • Preoperative AAA examination: report data on the access route, abnormalities in iliac arteries, fixation site of the endoprosthesis, aspect and measurements of the aneurysmal sac, and presence of parietal thrombi. • Postoperative AAA examination. 3.1.3. Examination Instructions and Protocols (Table 10) 3.1.4. Examination Protocol for Abdominal Aortic Aneurysm According to Recommendations from the Department of Cardiovascular Imaging 2 The examination must be conducted from the subxiphoid region to the aortic bifurcation, followed by the study of 821