Transcranial Doppler Monitoring Research Articles

Carotid artery elongation (carotid dolichoarteriopathy): some features of the structure and hemodynamics

The purpose of the study. Multimodal study of the state of the brachiocephalic arteries, with assessment of blood flow in the extra- and intracranial portions of the carotid arteries and brain perfusion, as well as the structure of the brain in patients with different types of elongation of the carotid arteries (ECA).Material and methods. The data of examinations of 79 patients (45 men (57.0%, average age – 61.0 ± 10.1 years) and 34 women (43.0%, 65.3 ± 13.6 years), average age 62.8 ± 11.8 years) during the year after ischemic stroke in posterior circulation were analyzed. ECA was verified by multispiral computed tomographic angiography (msCTA) in 44 patients (55.7% of the total number of cases), the control group was selected by gender and age with “case-control” elements and consisted of 35 (44.3%) patients without a mustache. All underwent msCTA of the thoracic aorta and BCA and CT perfusion examination, magnetic resonance imaging of the brain, duplex scanning of BCA and transcranial duplex scanning, transthoracic echocardiography, transcranial Doppler monitoring with microembolodetection.Results. We have registered intergroup differences, which can be divided into structural and functional. The former include: higher aortic arch location in patients with DCA: ThII – 6.3% vs. 0%, ThIII – 43% vs. 0%; ThIV – 28.1% vs. 62.9%* and ThV 21.9% vs. 37.1% (p < 0.0005); lower values of cervical spine height (114.70 ± 11.03 mm, vs. 120.46 ± 9.75 mm, p = 0.022), greater absolute length of the ICA (on the right – 101.32 ± 14.59 mm vs. 85.06 ± 12.07 mm, p < 0.0005; on the left – 100.00 ± 14.03 mm vs. 84.66 ± 12.63 mm, p < 0.0005). The presence of ECA was associated (p < 0.05) with a higher frequency of vertebral artery elongation. The severity of small vessel disease during MRI in individuals with ECA was slightly higher (not at the trend level, p = 0.076). Functional differences consisted in the registration of lower (p = 0.019) values of the end diastolic velocity in M1 of the middle cerebral arteries. The values of some perfusion indices in the blood supply of elongation arteries were lower than in persons without ECA. There were no cases of registration of microembolic signals in the ECA patients examined by us.Conclusion. In the individuals with ECA we examined, a complex of anatomical and hemodynamic features was determined, which, both individually and collectively, cannot lead to a decrease in the level of blood flow or be a source of arterio-arterial embolism in the carotid system, regardless of the configuration of the ICA.

To assess the safety of laparoscopy in patients with CSF catheters draining distally into the abdomen.

This study evaluates the safety of laparoscopic procedures in patients with cerebrospinal fluid (CSF) catheters draining distally into the abdomen. A systematic search across PubMed, Scopus, and Ovid databases using pertinent keywords yielded 47 relevant papers, encompassing 197 cases, for analysis. In the pediatric cohort (n = 129), male (49.6%) and female (34.1%) cases were reported, while gender remained unspecified in 16.3%. Shunt indications included unspecified (126 cases) and Meningomyelocele (3 cases). Laparoscopic procedures encompassed gastric (72.1%), urologic (21.7%), and other (6.2%) indications. Peri-operative shunt management included subcostal incision and clamping (1), ICP monitoring and drainage (2), and distal shunt flow confirmation (1). The prevalent complication was mechanical obstruction (10.1%), followed by pseudocyst formation (1.5%) and infection (2.3%). In the adult cohort (n = 61), males (60.6%) and females (39.3%) with a median age of 55 years were observed. Management strategies encompassed sponge packing and mobilization (11), distal shunt flow confirmation (2), shunt clamping (3), Transcranial Doppler monitoring (2), and no manipulation (30). Shunt infection emerged as the primary complication (2). Overall, 24 patients encountered VP shunt-related complications post-laparoscopy. This study underscores the safety of laparoscopic interventions in patients with ventriculoperitoneal or lumboperitoneal shunts when facilitated by interdisciplinary cooperation. A meticulous preoperative assessment for shunt track localization, intraoperative visualization of shunt tip with CSF flow, vigilant perioperative anesthetic monitoring, and shunt dysfunction surveillance are crucial for favorable outcomes in laparoscopic procedures for these patients.

Analysis of Variables Associated with Positive Micro-Embolic Signals Detected by Transcranial Doppler in Patients with Atrial Fibrillation and Their Predictive Value for Embolic Risk.

This study examined the factors associated with positive micro-embolic signals (MES) on transcranial Doppler monitoring in patients with atrial fibrillation (AF), as well as the predictive value of MES for the risk of embolism in AF. Sixty-six patients who had micro emboli with AF were included in the positive group, and 75 patients who did not have micro emboli with AF served as the control group. The clinical data, congestive heart failure, hypertension, age ≥ 75 (doubled), diabetes mellitus, prior stroke or transient ischemic attack (doubled), vascular disease, age 65-74, female (CHA2DS2-VASc) score, D-dimer (D-d) level, echocardiography results, and brain magnetic resonance imaging (MRI) findings were compared between the two groups. Logistic regression models were used to analyze the relationship between positive micro emboli with CHA2DS2-VASc score, D-d, left atrial anteroposterior diameter (LAD), and silent cerebral ischemia (SCI) occurrence. The CHA2DS2-VASc score, D-d level, and LAD were significantly higher in the positive group than in the control group (P < 0.05) and were accompanied by a higher detection rate of SCI by brain MRI (P < 0.01). Elevated D-d levels, increased LAD, and the detection rate of SCI were all highly positively correlated with positive micro emboli. Also, CHA2DS2-VASc score ≥ 2 showed a significant positive correlation with positive micro emboli, and the higher CHA2DS2-VASc score was associated with a stronger correlation. The multivariate regression analysis demonstrated that positive micro-embolic was independently associated with SCI and a CHA2DS2-VASc score of ≥ 4. Positive micro emboli in patients with persistent AF are consistent with an increased risk of embolism, and are independently associated with a higher CHA2DS2-VASc score and SCI, which can be used as an indicator of individual embolic risk inpatients with AF.

Abstract 147: Utilization and Application of Transcranial Doppler Emboli Monitoring for Infective Endocarditis

Introduction The rapid growth of the elderly population, an increase in cardiac disease, and notable use of intracardiac prosthetic devices has led to an increased prevalence of infective endocarditis (IE). Among the sequelae observed with an IE diagnosis, acute ischemic stroke (AIS), subarachnoid hemorrhage (SAH), intracerebral hemorrhage (ICH), vasculitis, septic emboli, cerebral abscess, and infectious intracranial aneurysms (IIA) continue to complicate overall management of this disease. Current literature on neurological complications of IE includes limited data on the defined role of neuroimaging in dictating inpatient management. Transcranial doppler (TCD) emboli monitoring with high intensity signals (HITS) offers a real time, radiation‐free, relatively low cost, non‐invasive imaging option to potentially risk stratify and identify candidates for earlier intervention to prevent further cerebrovascular (CV) complications. Methods We conducted an observational study of infective endocarditis cases admitted to our institution from April 2022 to May 2023 who had TCD with HITS completed. Baseline clinical characteristics (age, sex, date and timing of TCD with HITS study, date of last positive blood culture, organism of infection, other neuroimaging utilized) were recorded. Observations recorded included the results of the TCD with HITS studies, the overall incidence and timing of neurological complications (AIS, SAH, ICH, IIA, septic emboli, cerebral abscess), timing of valve surgery, and inpatient mortality rates. A positive HITS was defined as detection of cerebral microembolism during ultrasound monitoring of bilateral middle cerebral arteries (MCA) for 30 minutes using a TCD machine (VIASONIX Dolphin IQ). Results Between April 2022 to July 2023, we identified 22 patients with confirmed left‐sided infective endocarditis who underwent TCD with HITS. Mean age was 66 years (SD, 10), and 82% were men. Leading pathogen types were Enterococcus Faecalis (27%) and Staphylococcus Epidermidis (18%). CV complications were noted in 19/22 patients (86%), the most common being AIS (82%) and IPH (18%). Two patients (9%) were found to have a positive HITS study, both of which developed septic emboli that caused ischemic stroke in one case, and hemorrhagic stroke in the other case. Average days from admission to timing of TCD with HITS study was 8.5 days. 14/22 patients underwent valve surgery (64%) during the admission on average 9.2 days after TCD with HITS study in the negative HITS group versus 5 days in the positive HITS group. Of the positive HITS cases, one of them died inpatient. Conclusion The association between neurological complications in patients with IE and cerebral microemboli detected with TCD monitoring has yet to be elucidated. While our observational study was limited by our sample size, both of our IE patients who had positive TCD with HITS studies developed more severe CV complications, and aggressive care was sought out more urgently to further minimize complications. Future directions include pursuing a prospective study incorporating TCD with HITS monitoring for patients with IE in order to risk‐stratify neurological complications and safety of valve surgery.

Functional Transcranial Doppler (fTCD) investigation of brain lateralization following visual stimuli.

This preliminary investigation of the local cerebral perfusion evaluated by Transcranial Doppler (TCD) monitoring of the Posterior Cerebral Arteries shows that selective stimulation of visual hemifields evokes significantly different vascular responses. TCD can therefore allow for functional evaluation of lateralized enhancements in cerebral metabolism.Clinical Relevance-The cerebral lateralization evaluated with the functional TCD can be a useful and low-cost approach to evaluate the effectiveness of the rehabilitation therapy in post stroke subjects experiencing hemianopia or to assess cerebral reorganization after cerebrovascular accidents.

Cerebral blood flow autoregulation assessment by correlation analysis between mean arterial blood pressure and transcranial doppler sonography or near infrared spectroscopy is different: A pilot study.

Recently, cerebral autoregulation indices based on moving correlation indices between mean arterial pressure (MAP) and cerebral oximetry (NIRS, ORx) or transcranial Doppler (TCD)-derived middle cerebral artery flow velocity (Mx) have been introduced to clinical practice. In a pilot study, we aimed to evaluate the validity of these indices using incremental lower body negative pressure (LBNP) until presyncope representing beginning cerebral hypoperfusion as well as lower body positive pressure (LBPP) with added mild hypoxia to induce cerebral hyperperfusion in healthy subjects. Five male subjects received continuous hemodynamic, TCD and NIRS monitoring. Decreasing levels of LBNP were applied in 5-minute steps until subjects reached presyncope. Increasing levels of LBPP were applied stepwise up to 20 or 25 mmHg. Normobaric hypoxia was added until an oxygen saturation of 84% was reached. This was continued for 10 minutes. ORx and Mx indices were calculated using previously described methods. Both Indices showed an increase > 0.3 indicating impaired cerebral autoregulation during presyncope. However, there was no significant difference in Mx at presyncope compared to baseline (p = 0.168). Mean arterial pressure and cardiac output decreased only in presyncope, while stroke volume was decreased at the last pressure level. Neither Mx nor ORx showed significant changes during LBPP or hypoxia. Agreement between Mx and ORx was poor during the LBNP and LBPP experiments (R2 = 0.001, p = 0.3339). Mx and ORx represent impaired cerebral autoregulation, but in Mx this may not be distinguished sufficiently from baseline. LBPP and hypoxia are insufficient to reach the upper limit of cerebral autoregulation as indicated by Mx and ORx.

313 Passive Flow-Reversal With Balloon-Guide Catheter for Transfemoral Carotid Artery Stenting: Proof of Concept, Technical Description and Experience

INTRODUCTION: The use of modern transfemoral balloon guide catheters (BGC) for flow reversal during carotid artery stenting (CAS) is scarcely described in literature but represents a promising and efficient technique for embolic protection. METHODS: We performed a retrospective analysis of patients ≥ 18-year-old who underwent elective CAS with the use of flow-reversal through the Walrus BGC. The BGC is positioned in the common carotid artery and inflated, followed by opening of the stop-cock for passive reversal of flow. We utilized a robotic transcranial Doppler monitoring during this technique for proof of concept. Patients’ characteristics, procedural details and clinical follow-up were evaluated. RESULTS: One-hundred and ten patients were included. Mean age was 69.1 years ± SD 9.6 and 30 (27.3%) were female. Most common comorbidities were hyperlipidemia (81.8%) and hypertension (73.6%). 54 (49.1%) patients were symptomatic. 102 (92.7%) patients had stenosis ≥70%. Contralateral stenosis ≥50% was present in 54 (49.1%) patients. Distal filters were used in 91 (82.7%) cases. Angioplasty was performed in 86 (78.2%) patients. Stenting was successful in 100% of cases. There were no periprocedural TIA or stroke. Stroke or TIA and mortality were both observed in only two (1.8%) patients during 30-days follow-up, of which one was due to non-compliance with antiplatelet regimen. CONCLUSIONS: In our institution’s experience, this technique was safe, feasible and efficient, with 100% technical success and no periprocedural thromboembolic complications. More extensive studies are needed to establish the role of proximal protection with flow-reversal using modern BGCs.

Critical Closing Pressure and Cerebrovascular Resistance Responses to Intracranial Pressure Variations in Neurocritical Patients

BackgroundCritical closing pressure (CrCP) and resistance-area product (RAP) have been conceived as compasses to optimize cerebral perfusion pressure (CPP) and monitor cerebrovascular resistance, respectively. However, for patients with acute brain injury (ABI), the impact of intracranial pressure (ICP) variability on these variables is poorly understood. The present study evaluates the effects of a controlled ICP variation on CrCP and RAP among patients with ABI.MethodsConsecutive neurocritical patients with ICP monitoring were included along with transcranial Doppler and invasive arterial blood pressure monitoring. Internal jugular veins compression was performed for 60 s for the elevation of intracranial blood volume and ICP. Patients were separated in groups according to previous intracranial hypertension severity, with either no skull opening (Sk1), neurosurgical mass lesions evacuation, or decompressive craniectomy (DC) (patients with DC [Sk3]).ResultsAmong 98 included patients, the correlation between change (Δ) in ICP and the corresponding ΔCrCP was strong (group Sk1 r = 0.643 [p = 0.0007], group with neurosurgical mass lesions evacuation r = 0.732 [p < 0.0001], and group Sk3 r = 0.580 [p = 0.003], respectively). Patients from group Sk3 presented a significantly higher ΔRAP (p = 0.005); however, for this group, a higher response in mean arterial pressure (change in mean arterial pressure p = 0.034) was observed. Exclusively, group Sk1 disclosed reduction in ICP before internal jugular veins compression withholding.ConclusionsThis study elucidates that CrCP reliably changes in accordance with ICP, being useful to indicate ideal CPP in neurocritical settings. In the early days after DC, cerebrovascular resistance seems to remain elevated, despite exacerbated arterial blood pressure responses in efforts to maintain CPP stable. Patients with ABI with no need of surgical procedures appear to remain with more effective ICP compensatory mechanisms when compared with those who underwent neurosurgical interventions.

Exaggerated postural sway improves orthostatic cardiovascular and cerebrovascular control.

Healthy individuals with poor cardiovascular control, but who do not experience syncope (fainting), adopt an innate strategy of increased leg movement in the form of postural sway that is thought to counter orthostatic (gravitational) stress on the cardiovascular system. However, the direct effect of sway on cardiovascular hemodynamics and cerebral perfusion is unknown. If sway produces meaningful cardiovascular responses, it could be exploited clinically to prevent an imminent faint. Twenty healthy adults were instrumented with cardiovascular (finger plethysmography, echocardiography, electrocardiogram) and cerebrovascular (transcranial Doppler) monitoring. Following supine rest, participants performed a baseline stand (BL) on a force platform, followed by three trials of exaggerated sway (anterior-posterior, AP; mediolateral, ML; square, SQ) in a randomized order. All exaggerated postural sway conditions improved systolic arterial pressure (SAP, p = 0.001) responses, while blunting orthostatic reductions in stroke volume (SV, p < 0.01) and cerebral blood flow (CBFv, p < 0.05) compared to BL. Markers of sympathetic activation (power of low-frequency oscillations in SAP, p < 0.001) and maximum transvalvular flow velocity (p < 0.001) were reduced during exaggerated sway conditions. Responses were dose-dependent, with improvements in SAP (p < 0.001), SV (p < 0.001) and CBFv (p = 0.009) all positively correlated with total sway path length. Coherence between postural movements and SAP (p < 0.001), SV (p < 0.001) and CBFv (p = 0.003) also improved during exaggerated sway. Exaggerated sway improves cardiovascular and cerebrovascular control and may supplement cardiovascular reflex responses to orthostatic stress. This movement provides a simple means to boost orthostatic cardiovascular control for individuals with syncope, or those with occupations that require prolonged motionless standing.

Clinical Significance of the Characteristics of Microembolic Signals Recorded in the Recovery Period of Ischemic Stroke, a Cross-Sectional Observational Study

Background. Microembols detected during transcranial Doppler monitoring with microembolodetection (TCDM with MED) are different in nature and, accordingly, in structure, as well as in size and consequences of their impact on the cerebral vessels. The following biophysical characteristics of microembolic signals (MES) can be assessed during TCDM with MED: frequency, which indirectly reflects the structure of the microembolus, duration, which indirectly reflects the size of the microembolus, and power, which is an integral characteristic. The issues of the relationship between characteristics of MES and clinical indicators have been little studied according to literature.&#x0D; Aims study of the biophysical characteristics of microembolic signals recorded in patients with ischemic stroke, as well as the factors affecting these characteristics, the clinical and prognostic significance of microembolism.&#x0D; Methods. This is a cross-sectional observational study that is part of a prospective cohort study. Data on 28 patients in the recovery period of ischemic stroke are included, in whom the biophysical characteristics of MES were analyzed (the total number of cases in the cohort study was 1600), and who underwent: duplex scanning of the brachiocephalic arteries, transcranial duplex scanning, TCDM with MED, transthoracic echocardiography, magnetic-resonance tomography of the brain, electrocardiography. Study enrollment was carried out in the period from 2019 to 2021. The MES characteristics included frequency, duration, power, energy index (the product of power and duration), of which the MES power was the main one.&#x0D; Results. MES characteristics correlated with anthropometric parameters: average duration - with the patients age (r = 0.421; p = 0.029); average frequency with body surface area (r = 0.624; p = 0.010). The average power, duration and energy index of MES were significantly higher in persons with intraluminal masses in the carotid arteries (p 0.05). Correlations of biophysical characteristics of MES with blood flow velocities in brain vessels (inverse correlation between the duration of the MES and the value of the peak systolic velocity in the M2 segment of the right MCA r = 0.529, p = 0.02; correlations between the power of MES, as well as the duration of MES with peak systolic and end-diastolic velocities in the V4 segment of the right VA r = 0.4810.572, p = 0.0270.007), as well as with signs of atrophy of the temporal and occipital lobes of the brain were identified (inverse correlation between MES frequency and regional atrophy in the right temporal lobe r = 0.434, p = 0.038; inverse correlation between MES frequency and regional atrophy in the left temporal lobe r = 0.422, p = 0.045; inverse correlation between MES frequency and regional atrophy in the left occipital lobe r = 0.465, p = 0.025). Significant differences were found in the number of MES and their average power, duration, energy index in the presence and absence of atrial fibrillation (p 0.05).&#x0D; Conclusions. Age and, apparently, weight, as well as signs of atherosclerosis of the brachiocephalic arteries, influence the development of microembolism. In the presence of atrial fibrillation, material microembolism is observed predominantly, and the number of MES and their characteristics which reflect the size of microemboli are significantly higher. The relationship between the duration of MES and the characteristics reflecting the blood supply in the basin of the middle cerebral artery, as well as between the frequency of MES and the presence of regional atrophy in the temporal and occipital lobes of the brain according to magnetic resonance imaging was revealed.

Point of care transcranial doppler guiding the efficiency of selective cerebral perfusion during extracorporeal circulation for surgical repair of aortic arch hypoplasia with ligation of patent ductus arteriosus and pulmonary artery banding

The perioperative management of patients undergoing major surgery at high risk of developing neurological complications should include an individualized strategy for neuromonitoring in order to avoid potential brain insults. In this case report, we present our experience in the intraoperative management of an aortic coarctation correction surgery with pulmonary banding, where Transcranial Doppler (TCD) monitoring provided informations about cerebral blood flow. In this report we highlight the benefits of TCD in the optimization of cerebral perfusion and oxygen delivery which can be decisive in improving the postoperative outcome.

Cerebral hemodynamic monitoring combined with infusion test in hydrocephalus

IntroductionDisturbance in cerebrospinal fluid (CSF) circulation may overlap with abnormality of cerebral blood flow (CBF) in hydrocephalus. Transcranial Doppler (TCD) ultrasonography is a non-invasive technique able to assess CBF velocity (CBFv) dynamics in response to a controlled rise in ICP during CSF infusion tests. Research questionWhich TCD-derived cerebral hemodynamic parameters change during controlled rise of ICP, and in which direction? Material and methodsInfusion tests combined with TCD monitoring and non-invasive monitoring of arterial blood pressure (ABP) were conducted in 65 hydrocephalic patients. TCD-based hemodynamic variables: spectral pulsatility index (sPI), compliance of CSF space (Ci), cerebral autoregulation index (Mx), critical closing pressure (CrCP), cerebrovascular wall tension (WT) and diastolic closing margin (DCM-distance between diastolic ABP and CrCP) were calculated retrospectively. ResultsDuring the test ICP increased on average to 25 mm Hg (p < 0.0001), with a parallel decrease in cerebral perfusion pressure (CPP, p < 0.0003). The CBFv waveform changed, showing a rise in sPI (p < 0.0001). Ci decreased inversely proportional to a rise in ICP, and correlated well with changes of compliance calculated from the Marmarou model. CrCP increased in response to rising ICP (p < 0.001) while WT decreased (p < 0.002). DCM correlated with cerebrospinal elasticity (R = −0.31; p < 0.04). Cerebral autoregulation was worse in patients with normal CSF circulation, measured as resistance to CSF outflow (Rout): Pearson correlation between Mx and Rout was R = −0.41; p < 0.02. ConclusionA controlled rise in ICP affects cerebral hemodynamics in a moderate manner. Parameters like cerebral autoregulation index or DCM correlate with CSF dynamics and may be considered as supplementary variables for the diagnosis of hydrocephalus.

The value of transcranial Doppler monitoring of cerebral blood flow changes during carotid endarterectomy performed under regional anesthesia - A case series.

Patients with unilateral hemodynamically significant carotid stenosis scheduled for elective CEAs were included. Ultrasound-guided intermediate plexus block was used for regional anesthesia. TCD monitoring of the middle cerebral artery mean blood flow velocity (MCAV) was performed throughout the procedure. MCAVs were offline analyzed during different phases of CEA: (1) resting state, before regional block, (2) after block, before incision, (3) before cross-clamp, (4) after cross-clamp, (5) 5 min after cross-clamp, (6) 10 min after cross-clamp, (7) after declamping, and (8) during the postoperative period (4-6 h). Shunt insertion based on the deterioration of neurological symptoms after cross-clamping was necessary for 11/66 patients (16.6%). In these symptomatic patients, the ipsilateral percent decrease of the MCAV was more than 70% in 8 out of 11 cases (72.7%). In asymptomatic patients, without shunt insertion, the average decrease of MCAV was less than 50%. Neurological symptoms referring to cerebral ischemia may be superior to TCD monitoring of cerebral blood flow for detecting the necessity of a shunt. Regional anesthesia enables reliable, symptom-based monitoring of CEAs.

Microembolic signals and antiplatelet therapy in Moyamoya angiopathy.

Embolism as a cause of stroke is widely neglected in Moyamoya angiopathy (MMA), and recommendations for use of antiplatelet therapy (APT) vary. We examined the presence of microembolic signals (MES) during transcranial Doppler (TCD) monitoring and assessed the effects of APT on the occurrence of MES in MMA. We retrospectively analysed patients with MMA treated at our centre between 2011 and 2021. TCD was performed at first presentation and at most visits, while number of visits varied between individual patients. TCD was performed for 30min bilaterally. Patient demographics, vascular risk factors, and antiplatelet treatment were collected from each clinic visit and ischemic and haemorrhagic episodes were captured as recorded during follow-up visits. 209 patients were included in the analysis (mean age 38.7 ± 15.3, 28% male). 21 patients with 27 MES-positive TCD examinations were identified (10%). Patient characteristics were similar in MES-positive and MES-negative groups. However, recent ischemic events were detected at a significantly higher rate in MES-positive patients (42.9% vs 4.8%, p < 0.001). After MES detection, change of antiplatelet drug regime was performed, leading to loss of MES in all cases. Dual APT was preferably used in the MES-positive group (p < 0.001) but no significant difference of haemorrhage during follow-up-visits was observed. Reduction of APT before bypass-surgery triggered MES in four patients. APT is required in patients with MMA. MES monitoring may help to identify risk patients in need of intensified APT.

Endovascular ascending aortic pseudoaneurysm repair under image fusion guidance and transcranial Doppler monitoring

We describe a 78-year-old woman with a large ascending aortic pseudoaneurysm who underwent thoracic endovascular aortic repair under intraoperative image fusion guidance and real-time transcranial Doppler (TCD) monitoring. TCD monitoring revealed a total of 419 microembolic signals throughout the procedure, with the majority occurring as the first stent graft crossed the ascending aorta. Two days later, she underwent endovascular repair of a graft type IA endoleak. We highlight the role of image fusion guidance and TCD monitoring in enabling successful thoracic endovascular aortic repair in an elderly woman and in identifying procedural areas of improvement to minimize stroke risk.

Transfemoral Flow-Reversal for Carotid Artery Stenting with Balloon Guide Catheter: Proof of Concept with Robotic Transcranial Doppler.

In this video, we demonstrate our technique for transfemoral carotid artery stenting (CAS) with flow-reversal through a Walrus balloon guide catheter (BGC) using robotic transcranial Doppler (rTCD) monitoring. Before crossing the plaque for distal filter placement and/or angioplasty, the BGC is inflated and the three-way stopcock opened, allowing back-bleeding. Immediately, the rTCD shows a change in blood-flow direction, indicating flow-reversal, which likely occurs due to a passive pressure gradient between the intracranial compartment and the atmospheric pressure. Then, the filter is placed with reduced risk of displacing plaque fragments, and angioplasty and stenting are performed with dual protection afforded by the BGC and filter. This technique may confer greater safety for CAS. Although in this case rTCD was used for proof of concept, it could also be used as a tool to monitor embolic load during CAS procedures.

Intraoperative Transcranial Doppler Monitoring Predicts the Risk of Cerebral Hyperperfusion Syndrome After Carotid Endarterectomy

Cerebral hyperperfusion syndrome (CHS) is a rare but serious complication following carotid endarterectomy (CEA). The aim of this study was to identify intraoperative transcranial Doppler (TCD) hemodynamic predictors of CHS after CEA. Between January 2013 and December 2018, intraoperative TCD monitoring was performed for 969 patients who underwent CEA. The percentage increase in the mean velocity of the middle cerebral artery (MCAV%) at 3 postdeclamping time points (immediately after declamping, 5minutes after declamping, and after suturing the skin) over baseline was compared between CHS and non-CHS patients. CHS was diagnosed in 31 patients (3.2%), including 11 with intracranial hemorrhage. The MCAV% values at the 3 postdeclamping time points over baseline were 177% (81%-275%), 90% (41%-175%), and 107% (55%-191%) in the CHS group, significantly higher than those in the non-CHS group (40% [14%-75%], 15% [1%-36%], and 18% [3%-41%], respectively, all P<0.001). Receiver operating characteristic curve analysis showed that the 3 intraoperative MCAV% parameters all had excellent accuracy in identifying CHS (areas under the curve: 0.854, 0.839, and 0.858, respectively, all P<0.001). The predictive value of the model consisting only of preoperative parameters was significantly increased by adding the intraoperative TCD hemodynamic parameters (area under the curve: 0.747 vs. 0.858, P=0.006). Multivariate analyses identified the intraoperative MCAV% immediately after declamping (odds ratio: 9.840, 95% confidence interval: 2.638-36.696, P<0.001) as an independent predictor of CHS. Our results indicate that intraoperative TCD monitoring helps predict CHS after CEA at an early stage.

ASNM and ASN joint guidelines for transcranial Doppler ultrasonic monitoring: An update.

Today, it seems prudent to reconsider how ultrasound technology can be used for providing intraoperative neurophysiologic monitoring that will result in better patient outcomes and decreased length and cost of hospitalization. An extensive and rapidly growing literature suggests that the essential hemodynamic information provided by transcranial Doppler (TCD) ultrasonography neuromonitoring (TCDNM) would provide effective monitoring modality for improving outcomes after different types of vascular, neurosurgical, orthopedic, cardiovascular, and cardiothoracic surgeries and some endovascular interventional or diagnostic procedures, like cardiac catheterization or cerebral angiography. Understanding, avoiding, and preventing peri- or postoperative complications, including neurological deficits following abovementioned surgeries, endovascular intervention, or diagnostic procedures, represents an area of great public and economic benefit for society, especially considering the aging population. The American Society of Neurophysiologic Monitoring and American Society of Neuroimaging Guidelines Committees formed a joint task force and developed updated guidelines to assist in the use of TCDNM in the surgical and intensive care settings. Specifically, these guidelines define (1) the objectives of TCD monitoring; (2) the responsibilities and behaviors of the neurosonographer during monitoring; (3) instrumentation and acquisition parameters; (4) safety considerations; (5) contemporary rationale for TCDNM; (6) TCDNM perspectives; and (7) major recommendations.

Simultaneous monitoring of the middle cerebral and basilar arteries to detect right-to-left shunts using transcranial Doppler by agitated saline administration

Transcranial Doppler (TCD) is an easy, non-invasive, and real-time monitoring device for detecting right-to-left shunts (RLS). Nonetheless, it has limited benefits in patients with poor temporal windows. Therefore, we aimed to investigate whether the basilar artery (BA) window was as effective as the middle cerebral artery (MCA) in detecting RLS during TCD monitoring. Overall, we enrolled 344 patients with stroke, transient ischemic attack, headache, or dizziness. MCA and BA were monitored using a modified headset. To investigate the feasibility of the suboccipital window in detecting RLS, we instituted an evaluation tool with three tiers to evaluate microembolic signals (MESs) during TCD monitoring. Tier 1: TCD monitoring of the MCA (bilaterally) in the resting state, tier 2: TCD monitoring of the MCA (bilaterally) while performing the Valsalva maneuver, and tier 3: TCD monitoring of the index MCA and BA while performing the Valsalva maneuver. In tiers 2 and 3, a high agreement rate of 0.808 and 0.809 (p < 0.001), respectively, on the weighted kappa index, and a high intra-class correlation coefficient of 0.982 and 0.986 (p < 0.001), respectively, were observed on detecting MESs. Our data suggests that the BA window is as effective as the MCA window for detecting RLS on TCD.

Relationship of pharmacotherapy and the incidence of embolic complications of carotid reconstructive surgery

Aim. To evaluate the relationship between lipid-lowering and antiplatelet therapy and the incidence of cerebral microembolism and related complications in open and endovascular revascularization of the carotid arteries (CA).Material and methods. This single-center study involved patients with internal CA stenosis. The patients were divided into 2 groups depending on the surgery type performed: carotid endarterectomy (CEA) — 163 patients; CA stenting (CAS) — 71 patients. All patients underwent intraoperative transcranial Doppler monitoring to register cerebral embolism during CAS and CE.Results. In CAS, microembolism episodes were observed in 66,2% vs 22,1% of patients in the CEA group (p=0,04), the largest number of which was recorded during catheterization of the internal CA and embolic filter installation (p=0,000). There were no significant differences between the groups in terms of the stroke incidence. In 8 patients in the CAS group and 1 patient in the CEA group, a transient ischemic attack was observed within 30 days after surgery (p=4x10-4 ). Intraoperative embolism was a predictor of a neurological event in the early postoperative period (odds ratio (OR), 33,08; 95% confidence interval (CI): 3,49-56,37 (p6 months before surgery reduces the likelihood of embolism by 4 times (OR 0,25; 95% CI: 0,11-0,58 (p=0,001), while lipid-lowering and antiplatelet therapy combination — by 12,5 times (OR, 0,08; 95% CI: 0,01-0,40 (p=0,001)).Conclusion. Preoperative antiplatelet and statin therapy reduces the likelihood of embolism during the CA revascularization procedure.