Detection Of Microemboli Research Articles

Prolonged and repeated microemboli detection in acute ischemic stroke – The Norwegian Microemboli in Acute Stroke Study (NOR-MASS)

ObjectivesCerebral microemboli can be detected by transcranial Doppler monitoring (TCDM) and may elucidate stroke etiology, the effect of preventive therapy, and the risk of stroke recurrence. Microemboli detection is usually performed for up to 60 minutes, but due to temporal variability, microembolization may be missed if the monitoring time is too short. We aimed to assess the time course of microembolization in acute ischemic stroke and explore the utility of prolonged and repeated microemboli detection. Materials and MethodsPatients with suspected ischemic stroke and symptom onset within 24 hours were examined with bilateral, stationary TCDM for one hour followed by unilateral, ambulatory TCDM for two hours. Unilateral TCDM was repeated for the following two days and after three months. ResultsWe included 47 patients, of which 41 had ischemic stroke, five had transient ischemic attack, and one had amaurosis fugax. Microemboli were detected in 60 % of patients. The occurrence was highest within 24 hours after onset and significantly lower at three months. Prolonged and repeated microemboli detection yielded only one additional microemboli-positive patient. Hence, patients who initially were microemboli negative tended to remain negative. We could not demonstrate an association between microemboli occurrence and clinical outcome or stroke recurrence. ConclusionsMicroembolic signals are frequent within 24 hours after ischemic stroke onset, but prolonged and repeated microemboli detection did not increase the yield of MES positive patients. Clinical Trial Registration-URLhttp://www.clinicaltrials.gov. Unique identifier: NCT03543319.

Clinical relevance of transcranial Doppler in a cardiac surgery setting: embolic load predicts difficult separation from cardiopulmonary bypass

BackgroundDuring cardiac surgery, transcranial Doppler (TCD) represents a non-invasive modality that allows measurement of red blood cell flow velocities in the cerebral arteries. TCD can also be used to detect and monitor embolic material in the cerebral circulation. Detection of microemboli is reported as a high intensity transient signal (HITS). The importance of cerebral microemboli during cardiac surgery has been linked to the increased incidence of postoperative renal failure, right ventricular dysfunction, and hemodynamic instability. The objective of this study is to determine whether the embolic load is associated with hemodynamic instability during cardiopulmonary bypass (CPB) separation and postoperative complications.MethodsA retrospective single-centre cohort study of 354 patients undergoing cardiac surgery between December 2015 and March 2020 was conducted. Patients were divided in tertiles, where 117 patients had a low quantity of embolic material (LEM), 119 patients have a medium quantity of microemboli (MEM) and 118 patients who have a high quantity of embolic material (HEM). The primary endpoint was a difficult CPB separation. Multivariate logistic regression was used to determine the potential association between a difficult CPB separation and the number of embolic materials.ResultsPatients who had a difficult CPB separation had more HITS compared to patients who had a successful CPB separation (p < 0.001). In the multivariate analysis, patients with MEM decreased their odds of having a difficult CPB weaning compared to patients in the HEM group (OR = 0.253, CI 0.111–0.593; p = 0.001). In the postoperative period patients in the HEM group have a higher Time of Persistent Organ Dysfunction (TPOD), a longer stay in the ICU, a longer duration under vasopressor drugs and a higher mortality rate compared to those in the MEM and LEM groups.ConclusionThe result of this study suggests that a high quantity of cerebral embolic material increases the odds of having a difficult CPB separation. Also, it seems to be associated to more complex surgery, a longer CPB time, a higher TPOD and a longer stay in the ICU. Six out of eight patients who died in this cohort were in the HEM group.

Detection of microemboli in patients with acute ischaemic stroke and atrial fibrillation suggests poor functional outcome.

We investigated the burden of microembolic signals (MES) in patients with acute ischaemic stroke (AIS) and atrial fibrillation (AF), assessing their impact on functional outcomes. This multicentre international prospective cohort study involved patients with AIS and either a known or newly diagnosed anticoagulant-naïve AF. All centres utilised the same transcranial Doppler machine for 1-h monitoring with bilateral 2 MHz probes within 24 h of symptom onset. Recordings underwent MES analysis by a blinded central reader. The primary objectives were to ascertain the MES proportion and its association with functional outcomes assessed by the modified Rankin scale (mRS) score at 90 days. Between September 2019 and May 2021, we enrolled 61 patients, with a median age of 78 years (interquartile range 73-83) and a median stroke severity score of 11 (interquartile range 4-18). MES were observed in 14 patients (23%), predominantly unilateral (12/14, 86%), with a median rate of 6 counts/hour (interquartile range 4-18). MES occurrence was higher post-thrombectomy and among those with elevated brain natriuretic peptide levels (p < 0.05). A worse mRS score of 3-6 was more frequent in patients with MES, occurring in 11/14 (79%), compared to those without MES, 20/47 (43%), with an adjusted odds ratio of 5.04 (95% CI, 1.15-39.4), p = 0.04. Nearly a quarter of patients with AIS and AF exhibited silent microembolization after the index event. Detecting MES within 24 h post-stroke (using transcranial Doppler) could signify a marker of poor functional outcomes. Subsequent trials will assess if very early antithrombotic treatment might enhance outcomes in this highly selective group of cardioembolic stroke patients. (Clinicaltrials.gov ID: NCT06018090).

The Relationship of Carotid Artery Plaque and Stenosis with Microemboli

Objective: Microembolic signals (MES) are markers that can be detected by Transcranial Doppler Ultrasonography (TCD) and are risk factors for stroke. The aim of our study is to explore the relationship between the number of MES and the extent of carotid stenosis as well as plaque morphology. Our goal is to provide a fresh perspective on the treatment of carotid stenosis. Materials and Methods: A total of 95 patients, who were admitted to the emergency department of Sultan 2.Abdülhamid Han Training and Research Hospital and were hospitalized with a diagnosis of stroke, were enrolled in the study. Patients with high-risk cardiac diseases were excluded from the study. Detailed medical histories, risk factors, and current medical treatments of the patients were documented, and microemboli detection was conducted using Transcranial Doppler (TCD). The number of microemboli in TCD was obtained by averaging the results of 2 consecutive half-hour follow-ups in a region. Carotid stenosis rates of the patients were determined by computed tomography angiography (CTA) according to the North American Symptomatic Endarterectomy Trial (NASCET) classification, and the plaque morphology was determined according to the Gray-Weale scale of carotid ultrasonography. Patients were categorized into symptomatic and asymptomatic carotid stenosis groups, and the number of microembolic signals (MES) was compared between these groups. Result: MES numbers of 95 patients with symptomatic carotid stenosis; while MES was not detected in 47.4% (n=45); 35.8% (n=34) had 1-2 MES, 8.4% (n=8) had 3-4 MES and 8.4% (n=8) 5 or more MES were detected. The relationship between the MES obtained and carotid stenosis was statistically significant (p&lt;0.001). According to the type of plaque; while there is no MES in 68.2% (n=15) of Type-4 symptomatic stenosis, this rate is only 15% (n=3) in Type-1 stenosis. In addition, 20% (n=4) of Type-1 symptomatic stenosis had MES between 3-4 and 30% (n=6) of 5 or more MES. According to these results, the relationship between plaque type and the presence of MES is statistically significant. (p&lt;0.001) Similar results were obtained in asymptomatic carotid stenosis. Conclusion: TCD is an easy-to-apply, non-invasive imaging technique, and MES detectable by TCD are risk factors for stroke. The relationship between MES and carotid stenosis rate and plaque type heterogeneity is statistically significant.

Approaches to classification of microembolic signals in patients recovering from ischemic stroke

Introduction. Microembolus detection by transcranial Doppler (TCD) is the only non-invasive modality for visualization of cerebral embolism. Currently, there is no unified classification of recorded microembolic signals (MES) that could be used in clinical practice.&#x0D; The aim of the study is to investigate biophysical MES parameters in patients with ischemic stroke, as well as to assess approaches to microemboli differentiation by structure and origin to improve the diagnostic accuracy of the method and to reduce the risk of recurrent ischemic events.&#x0D; Materials and methods. The inclusion criterion was TCD-detected signs of MES. We analyzed the data of 28 patients with ischemic stroke (9 women and 19 men; mean age was 58 years 13). We recorded power, duration, and frequency for each MES, and calculated an energy index.&#x0D; Results. A total of 938 MES were reported. In patients with cardioembolic stroke and all other pathogenetic stroke subtypes, biophysical parameter limits were as follows: 14.65 dB for the average power, 9.45 ms for the average duration, and 0.16 J for the average energy index. For patients with atrial fibrillation, characteristic MES power was found to be 13 dB. The MES frequency limit was determined to be 650 Hz for microemboli differentiation by acoustic density.&#x0D; Conclusion. The data obtained can be used to further search for optimal limit ranges for biophysical parameters of various MES in order to establish a single MES classification, which will increase the diagnostic value of microembolus detection by TCD in stroke treatment practice.

Diagnostic criteria for determining the type of the right-to-left shunt using contrast-enhanced transcranial Doppler ultrasound in young patients with ischemic stroke/transient ischemic attack

Objective. To determine specific diagnostic criteria for detecting the type of the right-to-left shunt by contrast-enhanced transcranial Doppler ultrasound (cTCD) in young patients with paradoxical embolism and ischemic stroke/TIA. Material and methods. The study included 64 ischemic stroke or transient ischemic attack patients (age 28–44 years) with patent foramen ovale (PFO), atrial septal defect (ASD) or pulmonary arteriovenous malformation (PAVM). cTCD was used to assess the degree of shunting, its change during the Valsalva maneuver (VM), time to the fi rst microembolic signal (MES) detection, and the duration of MES registration. Results. According to cTCD data, 20% of patients with PFO had no shunt at rest, and 80% had a mild to moderate right-to-left shunt. After VM, a severe shunt was detected in 75% of patients in this group and a moderate shunt in 25%. All patients with ASD and PAVM had a marked shunt at rest. The difference in time to first MES detection from the start of contrast administration was not statistically significant for all groups. The duration of MES registration that indicated shunting was shorter in patients with PFO compared to those with ASD (p &lt; 0.001) or with PAVM (p &lt; 0.001) and it was significantly longer in patients with PAVM compared to those with ASD (p &lt; 0.001). Conclusion. The key diagnostic criteria to defi ne the right-to-left shunt type are the functional shunt degree at rest and the duration of MES registration. Severe shunting at rest can suggest the presence of ASD or PAVM, while the duration of MES registration &gt; 2 min suggests a PAVM.

Non Vitamin k Antagonist Oral Anticoagulation Assessment in Non Valvular Atrial Fibrillation Using Transcranial Doppler Ultrasonography

<i>Background</i>: Warfarin with optimized international normalization ratio (INR); is significantly affect the Micro embolic signals (MES), in many studies. Non vitamin k antagonist oral anticoagulants (NOACs) are recently approved for stroke prevention in non valvular AF. In contrast to Warfarin; effect of NOACs on MES is not yet fully researched. <i>Aim</i>: To determine the effect of NOACs on MES, in comparison to warfarin in non valvular AF, to reflect the potential embolization risk. <i>Methods</i>: The incidence and number of MES was studied in patients with non valvular AF. Two groups in the current study; the first, patients were put on warfarin with INR levels were optimized to (2-3), and considered as a control group. The second; patients were put on NOAC (rivaroxaban, 15 mg /day). Study patients were recruited from cardiology outpatient clinics and departments (Al-Azhar University hospitals; Cairo and New Damietta, Egypt). Patients of the both groups were subjected to MES detection and counting by transcranial Doppler ultrasonography (TCD) monitoring. <i>Results</i>: MES did not detected in 22.5% in study groups; no statistically significant differences between study groups. The incidence and number of MES; within the warfarin group; MES were detected in (30 patients, 75%), while within the rivaroxaban group (32 patients, 80%). The average number of MES; in group one were (11.65 ±7.20), and in group two (11.50 ±7.20), with no significant statistical difference also. <i>Conclusion</i>: The effect of warfarin and NOAC use is not statistically different and Rivaroxaban is not inferior to warfarin.

Abstract Number ‐ 140: Transcranial Doppler Emboli Monitoring for Stroke Prevention after Flow Diversion: A Single Center Experience

Introduction Following the favorable clinical and radiographical results of flow diversion, its use has continually expanded for the treatment of complex intracranial aneurysms. The high metal surface of flow diverters (FD) increases the risk of thromboembolic complications. Current emboli monitoring data after FD placement is limited. Transcranial doppler (TCD) offers a non‐invasive evaluation of microembolic signals and might be a valuable tool to prevent ischemic complications. We evaluated the rate of embolic signals and their management after FD implantation. Methods We performed a retrospective, single‐center evaluation of adult patients who underwent a FD procedure with the Pipeline Embolization Device (PED) for unruptured intracranial aneurysms between 2012 and 2016. Covariates included patient demographics, comorbidities, aneurysm characteristics, procedure characteristics, and post‐procedure TCD emboli monitoring (immediate and &gt;12 hours post‐operative). TCD emboli signals were classified as positive (&lt; 15 microembolic signals) and strongly positive (&gt;15 signals). The primary outcome was the rate of symptomatic stroke at 2 and 12 weeks in these patients. Results 105 patients with 132 aneurysms were analyzed. Mean age was 59.7 years, and 78% were females. Mean aneurysm size was 7.8 ± 6.4 mm. Most of them were located in the paraclinoid region (40%). Two PEDs were implanted in 12 (11%) cases and adjunctive coiling was performed in 15 (14%) cases. Microemboli were detected in 11.4% of cases (12/105 patients) after PED deployment. In 5/12 patients, the emboli resolved upon repeat testing with no intervention. In 6/12 patients, further heparinization, additional clopidogrel administration, or change in antiplatelet agents were needed. These treatments reduced the microembolic events. In 1 patient who was clopidogrel‐resistant and a ticagrelor super‐responder, mechanical thrombectomy was necessary due to acute in‐stent thrombosis. There were no symptomatic strokes at 2 and 12 weeks. Conclusions TCD emboli monitoring can be a powerful non‐invasive tool for the early identification and prevention of thromboembolic events after FD implantation. Early detection of microembolic signals offers the possibility to modify postoperative management, avoid silent emboli, and potentially avoid symptomatic strokes.

Abstract WP110: Predictors Of False Positive Shunt Detected By Transcranial Doppler: When Is Intracardiac Echocardiogram Beneficial?

Background and Objective: Right to left shunts (RLS) found with patent foramen ovale (PFO) are implicated in the pathogenesis of cryptogenic stroke and a risk factor for neurological event. The capability and sensitivity of Transcranial Doppler ultrasound (TCD) to detect a PFO has been established. However, predictors of false positive shunts detected by TCD and benefit of intracardiac echocardiogram (ICE) when studies show conflicting results have not been determined. Methods: In this retrospective study, patients who underwent shunt testing with ICE ± endovascular atrial septal defect closure from 2018 till 2022 were included. We abstracted data regarding the type of study used for shunt detection such as transthoracic echocardiogram (TTE), transesophageal echocardiogram (TEE), ICE and TCD. PFO size and characteristics were evaluated. International consensus criteria were used for TCD PFO detection. Results: A total of 184 patients underwent ICE testing, of which 169 (93.4%) had prior TTE, 116 (63%) TEE, and 48 (25%) prior TCD. Among 48 patients with TCD, 24 had negative TTE and 4 had negative TEE. Mean (SD) age was 51.1(14.4). 110(59.8%) were female. Among all patient with ICE 169 (91.8%) had PFO. PFOs were detected in 38 out of 48 (79.1%) patients who had been assessed with both ICE and TCD, whereas 6 patients (12/5%) were found to have a RLS on TCD but no PFO on ICE, p&lt;0.01. Comparing ICE and TCD grading scores for shunt detected, 45.2% had higher grade by TCD compared to ICE, p= 0.17. Among the six false positive cases on TCD, four of them had shower of microembolization and 2 of them had 0-10 HITS microemboli detection. Conclusion: Transcranial Doppler ultrasound detection of right to left shunt remains highly sensitive and a non-invasive tool. Considering ICE as gold standard, TCD is associated with false positive shunt detection. Further studies are warranted to assess the shunt characteristics on TCD that are associated with higher predictive value for identifying PFO.

Взаимосвязь факторов риска микроэмболии с возрастом в восстановительном периоде ишемического инсульта

Identification of the age-related features of interaction between the risk factors of microembolism can improve understanding of the mechanisms underlying the development of ischemic stroke (IS). The study was aimed to assess the effects of age and other risk factors of stroke on the biophysical characteristics of microembolic signals (MES) recorded during the ischemic stroke recovery period. Transcranial Doppler ultrasound (TCD) involving microembolus detection (MED) was performed in 515 people, the data of 28 patients having a history of ischemic stroke, among them 9 women (32%) and 19 men (68%) aged 33–78 (average age 58 ± 13 years), were included in the study. Using the mixed-effects linear model it was found that age and interaction between age and atrial fibrillation affected the power of MES. The increase in the power of the recorded MES with age is observed, that is especially evident in patients with atrial fibrillation (р &lt; 0.0005). As for cardioembolic IS variant, the power and duration of MES turn out to be significantly higher in elderly patients (p &lt; 0.0005). The power of MES gradually increases with age in patients with no atherosclerosis and gradually decreases in patients with atherosclerosis, while MES power in patients with atherosclerosis in general (all age groups) is significantly higher (р &lt; 0.0005) than that observed in patients with no atherosclerosis.

Transcranial Doppler detects micro emboli in patients with asymptomatic carotid stenoses undergoing endarterectomy

ObjectiveThe objective of this study was to assess the primary endpoint defined as the detection of micro-embolic signals (MES) by the use of transcranial Doppler (TCD) in patients with asymptomatic carotid stenosis (≥70%) scheduled for carotid endarterectomy. The secondary endpoint consisted of testing the association of MES with stenosis severity, histopathological, and ultrasound characteristics. MethodsThis was a single-center, single-arm, prospective, observational trial. Computed tomography angiography and ultrasound assessment (Geroulakos classification) were mandatory as well as being under best medical therapy. MES number and characteristics were investigated in Holter mode TCD-X device with a standard 1.5 MHz probe. The time points of evaluation were: 24 hours preoperative, 24 hours postoperative, and 30 days postoperative. The histopathological analysis was performed according to the modified American Heart Association classification. One-way analysis of variance tested MES differences over time. Univariable and multivariable logistic regression tested variables potentially associated with MES. ResultsA total of 120 patients demonstrated a significant reduction of the mean number of MES (3.35 ± 10.04 and 0.82 ± 2.39; pre- and post-carotid endarterectomy, respectively), becoming undetectable at 30 days (P = .001). Hypoechogenic plaques assessed by ultrasound were a significant risk factor for MES (P = .001). The features of plaque vulnerability, such as hemorrhagic component (P = .011), neovascularization (P = .025), signs of inflammation (P = .027), and rupture of the fibrous cap (P = .002) were predictors of MES. Cap rupture was the only predictor in the multivariate analysis (odds ratio, 5.98; P = .030). The stenosis severity was not associated with MES (P = .95) ConclusionsPatients under best medical therapy had a preoperative embolic activity becoming no more detectable after surgery. Both ultrasound and histologic markers of vulnerability were predictors of MES, and stenosis severity was not associated. TCD gives better insight into the real embolic risk, and future studies should evaluate clinical results coming from its implementation with standard imaging techniques.ClinicalTrial.gov registration number NCT05134493.

Ischemic stroke with cancer: Hematologic and embolic biomarkers and clinical outcomes

BackgroundPatients with cancer and acute ischemic stroke (AIS) face high rates of recurrent thromboembolism or death. ObjectivesTo examine whether hematologic and embolic biomarkers soon after AIS are associated with subsequent adverse clinical outcomes. MethodsWe prospectively enrolled 50 adults with active solid tumor cancer and AIS at two hospitals from 2016 to 2020. Blood was collected 72–120 h after stroke onset. A 30‐min transcranial Doppler (TCD) microemboli detection study was performed. The exposure variables were hematologic markers of coagulation (D‐dimer, thrombin‐antithrombin), platelet (P‐selectin), and endothelial activation (thrombomodulin, soluble intercellular adhesion molecule‐1 [sICAM‐1], soluble vascular cell adhesion molecule‐1 [sVCAM‐1]), and the presence of TCD microemboli. The primary outcome was a composite of recurrent arterial/venous thromboembolism or death. We used Cox regression to evaluate associations between biomarkers and subsequent outcomes. ResultsDuring an estimated median follow‐up time of 48 days (IQR, 18–312), 43 (86%) participants developed recurrent thromboembolism or death, including 28 (56%) with recurrent thromboembolism, of which 13 were recurrent AIS (26%). In unadjusted analysis, D‐dimer (HR 1.6; 95% CI 1.2–2.0), P‐selectin (HR 1.9; 95% CI 1.4–2.7), sICAM‐1 (HR 2.2; 95% CI 1.6–3.1), sVCAM‐1 (HR 1.6; 95% CI 1.2–2.1), and microemboli (HR 2.2; 95% CI 1.1–4.5) were associated with the primary outcome, whereas thrombin‐antithrombin and thrombomodulin were not. D‐dimer was the only marker associated with recurrent AIS (HR 1.2; 95% CI 1.0–1.5). Results were generally consistent in analyses adjusted for important prognostic variables. ConclusionsMarkers of hypercoagulability and embolic disease may be associated with adverse clinical outcomes in cancer‐related stroke.

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.

Pulsed-wave Doppler for ultrasound-based tip location using bubble test: A pilot study.

MicroBubbles Time test (MBT), consisting in the rapid infusion of saline with addition of air microbubbles, visualized by B-mode echocardiography, represents a potential alternative to Intracavitary ECG (IC-ECG) and chest X-ray for central venous catheters (CVCs) tip location. Even if promising, this technique lacks of standardization: a clear time cut-off between bubble infusion and their detection in heart's right chambers hasn't been yet established. At these regard, microbubbles could be also detected as microembolic signals (MES) with an alternative ultrasound technique: the pulse wave Doppler (PW). The first aim of this pilot study is to establish agreement of MBT with PW test (MBT-PW) compared with reference standard IC-ECG and normal MBT for tip location on CVCs. Corrected tip's position was established through reference standard IC-ECG, afterward MBT-PW was performed, with the sample volume placed at tricuspid valve to detect MES simultaneously with micro-bubbles injection in CVCs. The second aim was to evaluate inter-observer variability for MES detection and grading. Eight patients were enrolled; we obtained three records for each patients (24 with MBT and 24 with MBT-PW, the two techniques were acquired simultaneously). Inter-methods agreement through reference standard IC-ECG versus MBT-PW and MBT versus MBT-PW methodic was satisfying (Cohen's kappa value = 1). MBT-PW and MBT signals were recorded within the first heart beat after microbubble infusion in all patients. Mean time delay thorough MBT-PW and MBT was 0.76 ±0.07 and 0.78 ± 0.07 s respectively; Intraclass correlation coefficient was 0.992 (95% CI: 0.981-0.996) suggesting excellent correlation. Inter-observer variability for positive MBT-PW evaluation was optimal (Cohen's kappa value was 1), while indicated substantial agreement for MES grade evaluation (Fleiss' Kappa value was 0.704; 95% CI: 0.328-1.000). Our study supports agreement between MBT-PW and reference standard IC-ECG for tip location. Satisfactory agreement was observed also for MBT-PW and MBT.

Incidence of cerebral microembolization in patients with nonvalvular atrial fibrillation using transcranial Doppler

Background and aim Atrial fibrillation (AF)-related stroke represented more than 79% of all strokes of cardiogenic origin. AF is the crucial factor of cardiogenic stroke. AF-related stroke is manifested with severe clinical manifestation, significant disability, high mortality, and easier relapse. The incidence of mortality is twice as high as non-AF-related stroke. The AF type is usually of nonvalvular origin. The current work is aiming to determine the incidence of cerebral microembolization in nonvalvular AF patients. Patients and methods The current study was a prospective study of two groups of individuals: control and nonvalvular asymptomatic AF cardiac condition, hypertension, age, diabetes, sex, and stroke (CHADS) score 2 or more. Patients were collected from the cardiology clinic and department (Al-Azhar University Hospital, New Damietta, Egypt). Patients were submitted to history taking, clinical assessment, echocardiography, and transcranial Doppler ultrasonography, and microembolic signal detection and count. Also, the transcranial Doppler was used to monitor both middle cerebral arteries. Results There was a statistically significant difference between the control and study groups in relation to the number of microembolic signals. Signals of microembolizations were detected in eight cases (all were in the study group). There was a positive correlation between embolic signals and patient age (r=0.424, P=0.020) and there was a significant association with female sex. In addition, there was a positive correlation between embolic signals and left-atrium dimension (r=0.502). Regarding correlation, there was a negative interaction between embolic signals and anticoagulation use (r=−0.413, P=0.023). Conclusion Asymptomatic embolic signals occur in patients with nonvalvular AF who are not being treated with anticoagulants at a significantly greater frequency than in age-matched controls.

Flow Cytometry Based Platelet Reactivity Testing to Predict the Occurrence of Per-operative Solid Microemboli During Carotid Endarterectomy

Peri-operative antiplatelet therapy (APT) aims to prevent thrombotic events such as stroke. High platelet reactivity ,despite the use use of APT, increases the risk of thrombotic events. Transcranial Doppler imaging (TCD) is used to detect peri-operative microembolic signals (MES) during carotid endarterectomy (CEA). Peri-operative MES are associated with an increased risk of procedural stroke and new silent lesions on diffusion weighted magnetic resonance imaging following surgery. The main components of TCD detected MES are platelet aggregates, and therefore patients displaying multiple MES during surgery could have benefited from more stringent APT. This study investigated whether the use of flow cytometry based platelet reactivity measurements were correlated with the incidence of pre-operative MES and thereby in the future suitable to predict patients at increased risk of peri-operative thrombotic events. Bilateral TCD with MES detection was performed in 197 patients undergoing CEA. Platelet reactivity was assessed with a flow cytometry based platelet reactivity assay measuring platelet response in whole blood. High on treatment platelet reactivity status was assessed for all patients. The secondary outcome was major adverse cardiovascular events (MACE) within one year. In total, 197 patients were included, 49 had peri-operative MES. The platelet response to adenosine diphosphate (ADP) correlated with MES (p= .021), and high on treatment platelet reactivity after adenosine diphosphate stimulation was associated with MACE (OR 2.34, 95% confidence interval 1.126 - 4.890, p= .023). Pre-operative platelet reactivity determined by flow cytometry after ADP stimulation correlated with the occurrence of intra-operative MES and post-operative MACE. Clopidogrel treatment showed the most substantial effect on reducing MES frequency and platelet reactivity measured by flow cytometry.

Abstract WP198: Hematological And Embolic Biomarkers And Clinical Outcomes In Patients With Cancer And Ischemic Stroke

Introduction: We previously showed that patients with cancer and acute ischemic stroke (AIS) have higher markers of coagulation, platelet, and endothelial activation, and more circulating microemboli than patients with AIS and no cancer. Herein, we evaluate whether these markers are associated with clinical outcomes in patients with cancer and AIS. Methods: In the MOST-Cancer prospective study, we enrolled 50 adults with active solid-tumor cancer and AIS at 2 New York hospitals from 2016-2020. We collected blood from participants 72-120 hours after stroke onset. We performed a 30-minute transcranial Doppler (TCD) microemboli detection study a median of 4 days after stroke onset. The exposure variables were hematological markers of coagulation (D-dimer, thrombin-antithrombin), platelet (P-selectin), and endothelial activation (thrombomodulin, soluble intercellular adhesion molecule-1 [sICAM-1], soluble vascular cell adhesion molecule-1 [sVCAM-1]), and the presence of microemboli on TCD. The primary outcome was a composite of recurrent arterial or venous thromboembolism or death. The secondary outcome was recurrent AIS. We used Cox regression to evaluate individual associations between biomarkers and subsequent outcomes. Results: Median age was 69 years (IQR, 60-76) and 24 participants (48%) were women. The most common cancers were lung (28%) and pancreatic (22%); 86% of participants had distant metastases. During a mean follow-up of 278 days (SD, 367), 43 (86%) participants had the primary outcome of recurrent thromboembolism or death, including 28 (56%) who had recurrent thromboembolism, 13 who had recurrent AIS (26%), and 30 (60%) who died. D-dimer, P-selectin, sICAM-1, sVCAM-1, and microemboli were associated with the composite outcome (Table). Similar results were seen for recurrent AIS. Conclusion: Markers of hypercoagulability and embolic disease were associated with adverse clinical outcomes in cancer-related stroke.

Principle of carotid micro-embolic signal detection, and comparison of HITS detected in disaster-stricken area medical examinations and ones by pseudo-emboli detected in mock experiments

Principle of carotid micro-embolic signal detection, and comparison of HITS detected in disaster-stricken area medical examinations and ones by pseudo-emboli detected in mock experiments

The Emerging Clinical Utility of Neurosonology During COVID-19 Pandemic

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 infection. Over the last 2 years the virus has spread worldwide with enormous implications on the healthcare systems. COVID-19 patients suffer from mild upper-airway manifestations to pneumonia and severe acute respiratory distress syndrome and their hospitalizations are often prolonged. Neurological manifestations of the disease are common. Neurosonology (transcranial Doppler &amp; cervical duplex ultrasound) is an easily repeatable diagnostic imaging modality that can be simply applied at the bedside of COVID-19 patients with cerebrovascular diseases or in critically ill patients in the intensive care unit. Neurosonology may provide hemodynamic assessment of cerebral circulation, quantitative evaluation of increased intracranial pressure and detection of micro-embolic signals in real-time. Consequently, it may assist substantially in the diagnosis, risk stratification and therapeutic approach of COVID-19 patients with or without cerebrovascular complications. In the present narrative review, we discuss the emerging clinical utility of neurosonology during COVID-19 pandemic and highlight the upgraded role of neurosonology resulting from the combination of the established applications coupled with the reduced risk of virus spreading during ultrasound evaluation compared to other imaging modalities including computed tomography and magnetic resonance imaging.

Circulating microRNAs in Symptomatic and Asymptomatic Carotid Stenosis.

Background: Specific microRNAs (miRs) have been implicated in the pathophysiology of atherosclerosis and may represent interesting diagnostic and therapeutic targets in carotid stenosis. We hypothesized that the levels of specific circulating miRs are altered in patients with symptomatic carotid stenosis (sCS) in comparison to those in patients with asymptomatic carotid stenosis (aCS) planned to undergo carotid endarterectomy (CEA). We also studied whether miR levels are associated with plaque vulnerability and stability over time after CEA.Methods: Circulating levels of vascular-enriched miR-92a, miR-126, miR-143, miR-145, miR-155, miR-210, miR-221, miR-222, and miR-342-3p were determined in 21 patients with sCS and 23 patients with aCS before CEA and at a 90-day follow-up. Transcranial Doppler ultrasound for detection of microembolic signals (MES) in the ipsilateral middle cerebral artery was performed prior to CEA. Carotid plaques were histologically analyzed.Results: Mean levels of miRs were not considerably different between groups and were only marginally higher in sCS than aCS concerning miR-92a, miR-210, miR-145, and miR-143 with the best evidence concerning miR-92a. After adjustment for vascular risk factors and statin pre-treatment, the effect sizes remained essentially unchanged. At follow-up, however, these modest differences remained uncorroborated. There were no relevant associations between miR-levels and MES or histological plaque vulnerability features.Conclusions: This study does not provide evidence for strong associations between specific circulating miRs and symptomatic state in a collective of comprehensively characterized patients with carotid stenosis. Further work is needed to elucidate the role of circulating miRs as targets in advanced carotid atherosclerosis.