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 represents approximately two-thirds of the cases and PE, one-third. Between 85% and 90% of DVT cases occur in the lower limbs. 83 VTE is a severe, preventable, and high-incidence disease – the third most common CVD, after acute myocardial infarction and CVA. Therefore, VTE is a serious and potentially lethal condition that can affect both inpatients and outpatients. After the first VTE episode, the chance of recurrence is high. 84,85 The venous thrombus often begins at the venous cuspid level (Figure 16) – either superficial or deep veins – and extends proximally in 13% of cases, retrogradely in 4%, and in both directions in 10%. 86-88 It can be partial – when occupying part of the lumen of the vein involved – or total. Thrombus located in the superficial system indicates superficial venous thrombosis, while DVT involves the deep venous system, and can strike one or more veins. 89 DVT in lower limbs is considered proximal if it affects the popliteal vein and/or proximal veins, with or without the involvement of other leg veins, and distal if it affects deep infrapatellar veins. 87,90 The objective examination is crucial as the clinical diagnosis alone is not reliable. The consequences of diagnostic error are severe. At an early stage, it can result in death and, at a later stage, depending on the pathophysiology (obstruction, reflux, or both), it can cause chronic venous hypertension, leading to debilitating conditions, such as post-thrombotic syndrome (PTS) and, in case of pulmonary involvement, pulmonary hypertension. 83,85,91 Furthermore, although effective, the unnecessary use of anticoagulant therapy results in higher costs and risk of hemorrhage. 92 Figure 16 – Two-dimensional image of a recent partial thrombus (acute) located in the valve sinus of the common femoral vein, shown through longitudinal (A) and transverse (B) planes. There is no complete collapse of the vein during compression (C). PARTIALLYINCOMPRESSIBLELCFV 6.2. Post-Thrombotic Syndrome PTS is defined as a combination of symptoms and objective findings in patients with DVT in lower or upper limbs. PTS is a debilitating disease and the most common and less known consequence of DVT. 93,94 One to five years after the DVT episode, approximately 30% to 50% of patients develop PTS, with 5% to 10% of them being severe cases, even when treated correctly. 94,95 PTS is a combination of venous hypertension secondary to flow obstruction or valvular incompetence andmicrocirculation and lymphatic abnormalities. 6.2.1. Deep Venous Thrombosis Diagnosis As the accuracy of the clinical diagnosis of DVT is low (< 50%), few patients with suspicion of DVT effectively have the disease (12% to 31%). Therefore, the recommendation is to perform an accurate and objective examination that can confirm or rule out DVT. 87,92,96 The current gold standard examination to diagnose DVT is compression VUS. 92,97 Three categories of examinations are used to determine the probability of DVT: 92,98 1. Clinical probability based on anamnesis and clinical examination 2. D-dimer levels 3. Imaging studies – the most commonly used is venous VUS, and the less used are venography, CTA, and venous magnetic resonance angiography. This guideline will cover only VUS. 835