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 Table 25 – Clinical indications for transcranial Doppler 115,116 Pathology Objective Observation Findings Brain death* Additional examination judicially valid to confirm cerebral circulatory arrest Standard study of anterior and posterior circulation arteries is mandatory. In case of residual blood flow, repeat after 12 hours Spectral curve with short peak systolic (< 50 cm/s) pattern and lack of diastolic flow; or "alternating" pattern (antegrade systolic and retrograde diastolic flow) Intracranial hypertension 111 Adjuvant indirect monitoring, including after decompressive craniectomy Qualitative analysis of the curve pattern, which can vary dynamically (inversion of the diastolic component delimits the irreversible stage) Progressive reduction of the diastolic component of the spectral flow curve according to the severity of hypertension Ischemic CVA (acute phase) 112,113 Monitoring of vessel reperfusion in case of thrombolysis (up to 4.5 hours after the start of the event), which lasts approximately 40 minutes (but can take more than 1 hour) Monitoring can be intermittent (conventional equipment) or continuous (transducer with "blind" Doppler fixed to a helmet adjustable to the patient's head) Reappearance of gradual flow according to the degree of reperfusion (TIBI scale of spectral curve pattern) Subarachnoid hemorrhage** 114 (Table 26) Diagnosis, assessment of severity, and monitoring of vasospasm, recommending early intervention Perform the examination at hospital admission and repeat it daily in case of vasospasm (critical period: 4 to 14 days after the event). Insonate all arteries at each examination Increase in mean flow velocity, according to the severity. Lindegaard ratio (velocity ratio between the middle cerebral artery and ipsilateral internal carotid) differentiates true spasm from hyperemia Patent foramen ovale*** 115 Shunt study in patients with ischemic CVA (transient or permanent) Intravenous infusion of shaken saline solution ("macrobubbles") associated with the Valsalva maneuver HITS (gaseous emboli) recorded in spectral curves are counted and classified according to the Spencer scale Sickle cell disease**** 116-118 (Table 27) Diagnosis and grading of intraluminal stenosis to stratify the risk of ischemic CVA and define the therapeutic approach. Monitoring of therapeutic response Mandatory in patients aged 2 to 16 years Mean flow velocity defines the periodicity of follow-up and approach (blood exchange) Migraine 119 Support for clinical diagnosis and differentiation from other headaches It can be performed in the intercritical period or during a painful crisis (different results) Measurement of pulsatility index and mean flow velocity in all vessels Transoperative monitoring 120,121 Preoperative assessment of CVA risk (monitoring of spontaneous microemboli; study of cerebral flow reserve) and peroperative monitoring of emboli and cerebral flow reduction during neurological and cardiovascular surgeries Continuous flow monitoring of middle cerebral arteries using two transducers with "blind" Doppler fixed to a helmet adjustable to the patient's head. Monitoring should continue in the postoperative (due to microemboli during this period) Report of emboli rate (solid and/or gaseous) and reduction in mean flow velocity compared to the baseline value (> 15%) determine the risk of ischemic CVA in the immediate postoperative period***** CVA: cerebrovascular accident; HITS: high-intensity transient signals; TIBI: thrombolysis in brain ischemia (scale). Information followed by asterisks (*) have additional data, presented in the text below. basilar arteries) and after the infusion of macrobubbles (that is, six times in total). In the event of a record with “curtain” pattern, stop the study (which will be considered positive). ***** Microembolic signals are detected in up to 70% of cases during the first hour after endarterectomy. A rate of 50 “microembolic signals”/hour occurs in up to 10% of cases and is predictive of ipsilateral focal ischemia. 121 7.3. Limitations of Transcranial Color Doppler Limitations of TCD basically result from the barrier the cranial bone represents to US. The use of contrast agents (“microbubbles”) greatly reduced the cases of inconclusive examinations due to a “lack of adequate windows.” The inexperience of the examining physician is also a crucial limiting factor; the learning curve is relatively long and requires dedication. 7.3.1. Essential Information to Include in Transcranial Doppler Reports The basic structure of any additional examinationmust have: • Patient’s identification (full name and age). • Clinical indication (the purpose of the examination will determine the type of TCD needed). • Technical quality of the examination (reporting possible issues that interfere in obtaining the necessary images for the study). • Record of all ultrasound windows used, and vessels examined (justifying the cases that were impossible to study). • Description of specific characteristics found in each technical resource used: - Color flow imaging – lumen patency or occlusion, laminar or turbulent (“mosaic”) pattern, direction (antegrade or retrograde). 840