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 The patient can be in a supine position or sitting. The head should be turned according to the window used at the time. The examiner can follow any sequence and must record images of spectral flow curves of each vessel examined – with identification –, according to the international standard. Including pictures or videos done with CFI ensures safety in confirming identification and possible anatomical variants (very common) or technical difficulties during the examination. Visualizing brain structures with B-scan determines the ability of the US in penetrating the bone wall in the window chosen and its usability for the examination. CFI will show (or not) flow in lumens of regional arteries, guiding the sample volume of pulsed wave Doppler with precision up to the lumen segment to be insonated to obtain the spectral flow curve. In addition to flow waveform morphology of each vessel, the routine of integral measurement of velocities has to be followed to ensure the collection of essential data to the hemodynamic analysis required in various pathologies with suspicion of DTC: PSV, EDV, mean velocity, RI, and PI (make sure that the equipment preset includes these calculations). Table 25 lists the clinical indications for TCD. *According to the Brazilian Guidelines for the Application of Transcranial Ultrasound as a Diagnostic Test for the Confirmation of Brain Death (defined by a group of experts from the Department of Neurosonology of the Brazilian Academy of Neurology in 2012), the criteria 122 are: • A single TCD is enough to confirm brain death. • TCD should be performed only in patients with previously established clinical diagnosis, in accordance with the current Brazilian regulations; moreover, the patient needs to have stable hemodynamic conditions (with or without the use of drugs), and minimum systemic systolic blood pressure of 90 mmHg (below this value, the examination will not have diagnostic validity). • A full standard TCD study is mandatory, with images in B-scan and color flow imaging (if available), and spectral flow curves of all intracranial trunk arteries. • Characteristic TCD findings in cerebral circulatory arrest : spectral flow curves with low-amplitude systolic wave (velocity < 50 cm/s) or curves with an alternating flow pattern (waves with antegrade systolic component followed by retrograde diastolic component). Table 24 – Identification of intracranial trunk arteries with "blind" transcranial Doppler 114 Artery Depth Flow Vm Flow direction in relation to the transducer Carotid siphon 55 to 70 mm 40 to 50 cm/s Positive or negative Ophthalmic 40 to 60 mm 20 cm/s Positive Distal internal carotid 55 to 70 mm 45 cm/s Positive Anterior cerebral 60 to 70 mm 60 cm/s Negative Middle cerebral 35 to 60 mm 70 cm/s Positive Posterior cerebral 55 to 70 mm 40 cm/s Positive (P1), negative (P2) Vertebral 55 to 70 mm 40 cm/s Negative Basilar 70 to 120 mm 45 cm/s Negative • Lack of flow in intracranial trunk arteries is not a criterion for brain death, except in cases in which a prior TCD was performed during the same hospitalization, with a record of flow in the arteries analyzed. • Anterior circulation: in case of inadequate transtemporal windows, reporting criteria for “vascular collapse” in both carotid siphons becomes mandatory to diagnose brain death. • Posterior circulation: if it is not possible to detect flow in the basilar artery, findings of “vascular collapse” in both intracranial vertebral arteries are crucial to diagnosing brain death; on the other hand, findings related to basilar “vascular collapse” in the presence of residual blood flow in at least one vertebral artery will invalidate the conclusive diagnosis of the examination as an indication of brain death in this region. • Residual blood flow can be detected in almost 20% of patients, especially in intracranial carotid arteries and in patients who underwent craniotomy (but this finding tends to disappear in a few hours). • The examination report must have a detailed account of the findings in each anterior and posterior circulation artery and be conclusive regarding the presence or lack of criteria for cerebral circulatory arrest that corroborate the clinical diagnosis of brain death. ***Spencer scale The number of embolic spikes shown in the device screen is also useful information since the greater the number of macrobubbles, more significant the size of the shunt(s) through the foramen ovale (Spencer scale): grade 0 – lack of HITS; grade 1 – 1 to 10 HITS; grade 2 – 11 to 30 HITS; grade 3 – 31 to 100 HITS; grade 4 – 101 to 300; grade 5 – > 300 HITS (“curtain effect”). Above grade 2, the right-left cardiac shunt is significant. In case of countless spikes (“curtain effect”), consider the possibility of pulmonary AVF. Examination protocol: peripheral intravenous infusion of solution with “macrobubbles” (8 ml of saline or glucose solution mixed with 2 ml of ambient air and shaken until it becomes homogeneous), followed immediately by vigorous Valsalva maneuver performed by the patient for 5 seconds and simultaneous insonation of spectral flow curves (pulsed wave Doppler) in cerebral and basilar arteries. The examination must be conducted in basal conditions (flow record with Valsalva maneuver in the right and left middle cerebral arteries and 839