Microembolic Signals Research Articles

Determination of cerebral blood flow velocity and microembolic signals in essential thrombocytosis by transcranial doppler ultrasonography

ABSTRACT Objectives The goal of treatment in essential thrombocytosis (ET) is to prevent vascular complications such as thrombosis and hemorrhage. This study aimed to evaluate the risk of cerebrovascular microembolism in ET patients due to detection of microembolic signals (MES) and measure cerebral blood flow velocity (CBFV) by Transcranial Doppler (TCD) ultrasonography. Material and Methods In this prospective case-control study, forty patients with diagnosed ET and age and sex-matched forty healthy controls were examined by the TCD sonography. Results The ET group had a higher rate of MES (8/40) in the right MCA than that in the control group (none), as measured by TCD. Five patients had MES at the left MCA compared to that in no subjects in the control group. The comparison of the ET and control groups in terms of CBFV parameters showed significantly lower end-diastolic FV at the right MCA in the ET group compared to that in the control group (p < 0.05). On the other hand; both pulsatility and resistance indices in the right and left MCA and the ratios of systolic to diastolic blood flow rates in the right and left MCA were significantly higher in the ET group than that in the control group. Discussion This study revealed that MES seems to be more common in patients with ET despite treatment. We could suggest that ET patients should be monitored more closely to address the potential risk of developing a cerebrovascular disease, which can be estimated by detection MES and raised CBFV, combine antiplatelet therapies to standard treatments.

Von Willebrand Factor Antigen, von Willebrand Factor Propeptide, and ADAMTS13 in Carotid Stenosis and Their Relationship with Cerebral Microemboli.

The relationship between von Willebrand factor antigen (VWF:Ag), VWF propeptide (VWFpp), VWFpp/VWF:Ag ratio, ADAMTS13 activity, and microembolic signal (MES) status in carotid stenosis is unknown. This prospective, multicenter study simultaneously assessed plasma VWF:Ag levels, VWFpp levels and ADAMTS13 activity, and their relationship with MES in asymptomatic versus symptomatic moderate-to-severe (≥50-99%) carotid stenosis patients. One-hour transcranial Doppler ultrasound of the middle cerebral arteries classified patients as MES+ve or MES-ve. Data from 34 asymptomatic patients were compared with 43 symptomatic patients in the "early phase" (≤4 weeks) and 37 patients in the "late phase" (≥3 months) after transient ischemic attack (TIA)/ischemic stroke. VWF:Ag levels were higher (p = 0.049) and VWFpp/VWF:Ag ratios lower (p = 0.006) in early symptomatic than in asymptomatic patients overall, and in early symptomatic versus asymptomatic MES-ve subgroups (p ≤0.02). There were no intergroup differences in VWFpp expression or ADAMTS13 activity (p ≥0.05). VWF:Ag levels and ADAMTS13 activity decreased (p ≤ 0.048) and VWFpp/VWF:Ag ratios increased (p = 0.03) in symptomatic patients followed up from the early to late phases after TIA/stroke. Although there were no differences in the proportions of symptomatic and asymptomatic patients with blood group O, a combined analysis of early symptomatic and asymptomatic patients revealed lower median VWF:Ag levels in patients with blood group O versus those without blood group O (9.59 vs. 12.32 µg/mL, p = 0.035). VWF:Ag expression, a marker of endothelial ± platelet activation, is enhanced in recently symptomatic versus asymptomatic carotid stenosis patients, including in MES-ve patients, and decreases with ADAMTS13 activity over time following atherosclerotic TIA/ischemic stroke.

Transcranial Doppler as a Predictor of Ischemic Events in Vertebral Artery Dissection.

Transcranial Doppler (TCD) helps identify patients with carotid dissections at risk of ischemic events (IEs). There is paucity of data identifying independent predictors of IE in vertebral arterial dissection (VAD). We sought to investigate the clinical and ultrasound predictors of IE. Patients with VAD admitted between June 2017 and February 2020 were evaluated clinically and with TCD; sonographic curves, microembolic signals (MES), and the breath-holding index (BHI) test were applied. Covariates found on univariate screen (P < .25) were included in a multivariable linear regression to identify independent predictors of IEs. Of 88 patients with 100 VAD, 75 (85.2%) were females with a mean age 37.9 ± 7.5 years. All patients received antiplatelet treatment. TCD monitoring lasted an average of 21 ± 2.1 minutes. TCD was abnormal in 23 cases (26.1%); 21 patients had abnormal sonographic curves in the vertebral/basilar arteries, while in 4 cases, MES were present and in 5 (4.5%), BHI was abnormal. None of the patients with a normal TCD had an IE. Six strokes occurred during follow up. On univariate analysis, male sex, diabetes, dyslipidemia, a previous myocardial infarct, migraine, time of consultation to the ER, bilateral VAD, MES, BHI abnormalities, post stenotic flow in the basilar artery (PFB), and basilar/vertebral velocities were significantly associated with the risk of IEs. In the multivariate analysis, only the presence of PFB was a significant predictor of IE (OR: 68.6, 95% CI 5-937, <.001). TCD in VAD predicts patients at high risk of IE.

Cerebral Microembolism in Intracerebral Hemorrhage: A Prospective Case–Control Study

Small and remote acute ischemic lesions may occur in up to one-third of patients with spontaneous intracerebral hemorrhage (ICH). Possible mechanisms include cerebral embolism, small vessel disease, blood pressure variability and others. The embolic mechanism has not been adequately studied. Using transcranial Doppler (TCD), we assessed the incidence of spontaneous microembolic signals (MESs) in patients with acute ICH. Twenty acute ICH patients were prospectively evaluated within 48h of hospital admission. Clinical and imaging data were collected. Continuous TCD monitoring was performed in both middle cerebral arteries for a one-hour period on days 1, 3 and 7 of hospital admission. Monitoring was performed in the emergency room, ICU or ward, according to patient location. We compared the frequency and risk factors for MES in patients with ICH and in 20 age- and gender-matched controls without history of ischemic or hemorrhagic stroke. The mean age was 57.5 ± 14.1years, and 60% were male. MESs were detected in 7 patients with ICH and in one control patient without ICH (35% vs 5%, p = 0.048). The frequency of MES on day 1 was 15% (3 of 20 patients), on day 3, 26% (5 of 19 patients) and on day 7, 37.5% (3 of 8 patients). Among patients with ICH, those with MES had a tendency to higher frequencies of dyslipidemia (83% vs 33%, p = 0.13) and lobar location of hemorrhages (71% vs 30%, p = 0.15). Two out of 6 patients with ICH who also underwent MRI had remote DWI lesions, of whom one showed MES on TCD. Micro-embolic signals occur in over one-third of patients with ICH. Further research is needed to identify the sources of cerebral microembolism and their relationship with small acute infarcts in ICH.

Microembolic Signals Detected by Transcranial Doppler Predict Future Stroke and Poor Outcomes.

Although transcranial Doppler detects microembolic signals (MES) in numerous settings, the practical significance of such findings remains unclear. Clinical information from ischemic stroke or transient ischemic attack patients (n = 248) who underwent embolic monitoring from January 2015 to December 2018 was obtained. MES were found in 15% of studies and ischemic recurrence was seen in 11% of patients (over 7 ± 6 days). Patients with MES had more lacunes than those without MES (1 ± 3 vs. 1 ± 2, P = .016), were more likely to have ischemic recurrence (37% vs. 6%, P < .001), undergo a future revascularization procedure (26% vs. 10%, P = .005), have a longer length of stay (9 vs. 4 days, P = .043), and have worse functional disability at discharge (modified Rankin Scale 3-6, 66% vs. 34%, P < .001). After controlling for several relevant cofactors, patients with MES were more likely to have ischemic recurrence (HR 4.90, 95% CI 2.16-11.09, P < .001), worse functional disability (OR 3.31, 95% CI 1.22-8.99, P = .019), and longer length of stays (β = .202, P < .001). MES may help to risk stratify patients as their presence is associated with ischemic recurrence and worse outcomes.

Brain Protection in the Endo-Management of Proximal Aortic Aneurysms

Neurological brain injury (NBI) remains the most feared complication following thoracic endovascular aortic repair (TEVAR), and can manifest as clinically overt stroke and/or more covert injury, detected only on explicit neuropsychological testing. Microembolic signals (MES) detected on transcranial Doppler (TCD) monitoring of the cerebral arteries during TEVAR and the high prevalence and incidence of new ischaemic infarcts on diffusion-weighted magnetic resonance imaging (DW-MRI) suggests procedure-related solid and gaseous cerebral microembolisation to be an important cause of NBI. Any intervention that can reduce the embolic burden during TEVAR may, therefore, help mitigate the risk of stroke and the covert impact of ischaemic infarcts to the function of the brain. This perspective article provides an understanding of the mechanism of stroke and reviews the available evidence regarding potential neuroprotective strategies that target high-risk procedural steps of TEVAR to reduce periprocedural cerebral embolisation.

Abolition of micro embolic signals in symptomatic carotid stenosis using dual antiplatelet therapy

Introduction : Micro-Embolic Signals (MES) detected by Trans-Cranial Doppler (TCD) in symptomatic carotid stenosis (CS) are considered a marker of subsequent stroke. We aimed to investigate the role of antiplatelet and antithrombotic agents in abolishing the MES in recently symptomatic CS. Materials and Methods: Transient ischemic attack/stroke patients with 50%CS or unstable carotid plaque, who were prospectively enrolled within 48hours of symptom onset, underwent bilateral middlecerebral artery one-hour TCD emboli monitoring within 48hours. Those with MES underwent second monitoring at 48hours of the initial study. Treatment given during the interval period was recorded. Results: Out of 73 patients enrolled from April 2016 to March 2019, 22 (17 males, mean age 67.4years) had ipsilateral MES on initial TCD (30.1%). Ten were on a single-antiplatelet agent (aspirin/clopidogrel) and one was on dual (aspirin&clopidogrel) therapy prior to this. Single-antiplatelet agent was started after TCD in seven, dual-agents in six and unfractionated-heparin in seven patients. Second TCD showed no MES in 14 patients. Only one out of three on a single antiplatelet agent alone had abolition of MES while all ten patients on dual-antiplatelet agents had a complete suppression (p=0.027,Chi-square test). Although heparin suppressed MES in 5/7 patients, all five had additional dual-agent therapy. MES was not abolished in one patient treated with heparin alone and another one on a combination of heparin and single-antiplatelet agent. Conclusion: Aspirin/Clopidogrel combination is very effective in suppressing arterial emboli in recently symptomatic carotid stenosis whereas unfractionated-heparin, single-antiplatelet agent or their combination is not useful for the same. Keywords: Micro-Embolic Signals, Trans-Cranial Doppler, Carotid stenosis.

Noninvasive Neurological Monitoring in Extracorporeal Membrane Oxygenation.

Optimal neurologic monitoring methods have not been characterized for patients on extracorporeal membrane oxygenation (ECMO). We assessed the feasibility of noninvasive multimodal neuromonitoring (NMN) to prognosticate outcome. In this prospective observational study, neurologic examinations, transcranial Doppler (TCD), electroencephalography (EEG), and somatosensory evoked potentials (SSEPs) were performed at prespecified intervals. Outcome at discharge was defined as favorable when modified Rankin Scale (mRS) 0-3; unfavorable when mRS >3. Of 20 patients (median age 60 years), 17 had TCDs, 13 had EEGs, and seven had SSEPs. With NMN, 17 (85%) were found to have neurologic complications. Fourteen (70%) had unfavorable outcomes. The unfavorable outcome was associated with absent EEG reactivity, coma, central cannulation, higher transfusion requirement, and higher Acute Physiology and Chronic Health Evaluation II and Sepsis-related Organ Failure Assessment scores. Seven patients had both SSEPs and EEGs and exhibited intact N20 responses despite poor outcomes. Four of these seven showed absent EEG reactivity despite intact N20. Eighteen thromboembolic events were observed, 14 of which had positive microembolic signals (MESs) in TCD. All 10 patients with arterial-sided thrombotic events had positive MES. NMN caused no adverse effects. NMN during ECMO is feasible and found high neurologic complication rate. EEG and TCD showed potential for prognostication of neurologic outcome.

Relationship of spontaneous microembolic signals to risk stratification, recurrence, severity, and mortality of ischemic stroke: a prospective study

IntroductionThe presence of microembolic signals (MES) during the acute phase of stroke is poorly understood, and its role and clinical application in relation to risk stratification and prognosis in patients remain uncertain. We assessed the prevalence of spontaneous MES in acute stroke and their relationship with risk stratification, stroke recurrence, morbidity, and mortality.Patients and methodsThis was a prospective cohort study conducted in the Stroke Unit. The MES presence was evaluated by transcranial Doppler (TCD) in patients with ischemic stroke within 48 h. The outcomes (risk stratification, morbidity, mortality, and recurrence of a stroke) were followed up for 6 months. The relationship between risk stratification and MES was obtained by odds ratios and that between MES and stroke recurrence, morbidity, and mortality using multiple logistic regression; considering statistical significance at P < 0.05.ResultsOf the 111 patients studied, 70 were men (63.1%) and 90 were white (81.1%), with a median age of 68 years. The MES frequency was 7%. There was a significant relationship between MES and symptomatic carotid disease (OR = 22.7; 95% CI 4.1–125.7; P < 0.001), a shorter time to monitoring (OR = 12.4; 95% CI 1.4–105.4; P = 0.02), and stroke recurrence (OR = 16.83; 95% CI 2.01–141; P = .009).DiscussionIt was observed that the stroke recurrence adjusted for prior stroke was higher and earlier among patients with MES detection. In conclusion, MES demonstrated a significant correlation with symptomatic carotid disease and a shorter DELAY until monitoring, and could be a predictor for the early recurrence of stroke in the long term.

Cerebral Microembolization in Left Ventricular Assist Device Associated Ischemic Events

IntroductionThe significance of microembolic signals (MES) detected by transcranial Doppler ultrasound emboli monitoring (TCD-e) in patients supported with left ventricular assist devices (LVAD) remains unclear. We aimed to investigate the relationship between cerebral microembolization detected by TCD-e and acute ischemic events in LVAD patients. MethodsWe reviewed consecutive patients with acute ischemic stroke or transient ischemic attack (TIA) in a prospectively collected database of LVAD patients. TCD-e exams consisted of monitoring the middle cerebral arteries for microembolic signals (MES) over 30 minutes. ResultsOf 515 persons with LVAD, 41 TCD-e studies were performed in 35 patients with acute ischemic stroke or transient ischemic attack (TIA) in a median of 1 day (Interquartile range [IQR]: 0-2) after the event. MES were present in 15 (44%) TCD-e studies with a median MES count of 4 (IQR: 2-15.5). Bloodstream infections were more common in patients with MES (38% versus 8%, P = .039). There were trends for lower international normalized ratio (1.39 versus 1.69, P = .214), lower activated partial thromboplastin (33.2 versus 36.6, P = .577), higher lactate dehydrogenase (531 versus 409, P = .323) and a higher frequency of pump thrombosis (13% versus 8%, P = .637) in patients with MES compared with those without MES. ConclusionsLVAD patients with acute ischemic stroke or TIA have a high prevalence of MES on TCD-e, which may serve as a marker for a prothrombotic state. Further study of MES in LVAD patients is warranted.

Abstract WP266: Microembolic Signals and Association With Stroke Etiology in Ischemic Stroke

Background: Microembolic signals (MES) detected by the transcranial Doppler ultrasound (TCD) have established prognostic value for stroke recurrence in patients with carotid stenosis. However, the frequency of MES in the context of other stroke etiologies remains unknown. Methods: All stroke admissions to Northwestern Memorial hospital between 2016-2018 who underwent TCD within the first 48 hours of admission were reviewed. Final stroke diagnosis was extracted from chart review. Presence or absence of MES was extracted from clinical TCD reports. Frequency of stroke etiology among MES groups were compared using chi-squared test. Results: A total of 789 patient charts were reviewed (mean age 62±17 years, 55% male). MES were present in 95 patients. Demographics and medical history of patients were not different among those with and without MES. Compared to patients without MES, those with MES were more frequently diagnosed with cardioembolic stroke (36.4% vs 21%, p =0.001) and less frequently with small vessel disease stroke (5.7% vs 24%, p &lt;0.001). However, there was no difference in the frequency of cryptogenic strokes between patients with and without MES ( p =0.844). Among patients with MES, the most frequent etiologies of stroke were cardioembolic (36.4%), cryptogenic (19.3%), large vessel disease (17.1%), and small vessel disease (5.7%). Conclusion: TCD detection of MES is seen across all stroke subtypes and may provide additional information for risk stratification in secondary stroke prevention. We are currently reviewing the prognostic utility of MES for stroke recurrence in this cohort.

Abstract WP359: Microembolic Signals Are Associated With Stroke Readmission in Patients With Ischemic Stroke

Background: Microembolic signals (MES) identified by transcranial Doppler (TCD) are strong predictors of recurrent stroke in patients with carotid disease. In this study, we investigated the association of MES with transient ischemic attack (TIA) or stroke readmission among ischemic stroke patients. Methods: We included a total of 789 patients (mean age 62±17 years, 55% male) who were consecutively admitted to Northwestern Memorial hospital with a diagnosis of stroke. All patients who underwent TCD studies within the first 48 hours of admission were included. Using an electronic database warehouse, patients were followed during 12 months for any hospital readmission due to ischemic stroke or TIA. Risk of stroke readmission was estimated using multivariate Cox proportional hazard models. Results: MES were detected in 95 patients on admission. During 12 months of follow-up, incidence rates for stroke and TIA readmission, and stroke readmission alone were 23.0 and 7.0 per 100 person-years across the entire cohort, respectively. In multivariate adjusted models, patients with MES, as compared to patients without MES, had 1.80-fold (95% CI=1.07, 2.53; p =0.008) higher risk of stroke and TIA readmission, and 2.30-fold (95% CI=1.13, 4.67, p =0.021) higher risk of readmission due to stroke alone. Conclusion: We showed that the presence of MES early after stroke admission is associated with higher risk of stroke and TIA readmission in stroke patients. This not only highlights the importance of identifying MES in the stroke population upon first admission, but also the need to further identify and implement therapeutic strategies to reduce stroke burden and prevent readmission in this high-risk population.

Abstract TP351: Microembolic Signals Monitoring in Acute Intracerebral Hemorrhage

Background: The etiology of remote DWI lesions in acute intracerebral hemorrhage (ICH) is still unknown. Postulated mechanisms include intracranial or extracranial emboli, small vessel abnormalities and ischemia following acute intracranial hypertension. Our aim is to evaluate the presence of spontaneous microembolic signals (MES) using transcranial Doppler (TCD) in acute ICH patients. Methods: Twenty patients with acute ICH were prospectively enrolled and monitored with TCD for 1 hour on admission days 1, 3 and 7. TCD monitoring was performed using 2MHz probes. Results: Of the 20 patients evaluated, 40% were females and mean age was 55.6±14.1. Eight patients (40%) had dyslipidemia, 15 (75%) hypertension, 5 (20%) diabetes, 2 (10%) ethanol abuse, 6 (30%) smoking and 1 (10%) had prior ischemic stroke. Most frequent location was lobar (9 patients). The mean hematoma volume was 13,5±17,9 ml. Of six patients who underwent MRI, 2 (20%) had remote DWI lesions. Embolic sources were found in 3 patients (1 with atrial fibrillation and 2 with large artery atherosclerosis). Microembolic signals were detected in seven patients (35%). Conclusion: The high occurrence of microemboli in patients admitted with acute ICH indicates a possible embolic mechanism for DWI lesions in these patients.

Abstract WP253: Diagnostic Evaluation and Outcome of Cerebral Fat Embolism: Single Center Retrospective Review

Introduction: Cerebral Fat Embolism (CFE) is an underappreciated complication of trauma and orthopedic surgery whose diagnosis is mostly based on clinical suspicion. The utility of diagnostic testing is poorly defined. Methods: Using discharge diagnosis codes and a stroke database at a Level 1 Trauma Center, we performed a retrospective chart review of diagnostic workup and outcome for CFE from 2005 to 2019. Among those with a diagnosis of systemic fat emboli syndrome after long-bone fracture, cerebral involvement was established based on altered mental status, retinal findings, brain MRI findings or a combination of these. This report focuses on those who had MRI, all of which had findings of CFE. Results: Forty patients with CFE were identified, comprising 0.3% of all patients admitted with long-bone fractures. Of these patients, the average age was 39 years (SD 22), 30 (75%) were men, 28 (70%) had hypoxemia, 2 (5%) had petechial rash, and 29 (73%) were comatose, including 16 (40%) following orthopedic surgery. Brain MRI findings of CFE included scattered diffusion-restriction (60%), confluent white-matter edema (33%) and diffuse petechial hemorrhage (30%), with 27% having multiple findings of CFE. Ophthalmologic evaluation revealed exudates or hemorrhage suggestive of Purtscher-like retinopathy in 20 (91%) of 22 patients examined. Transcranial doppler microembolic signals (MES) were detected in 17 (53%) of 32 patients examined and were associated with scattered diffusion-restriction on MRI (chi square, p =0.01). Twelve patients (30%) died before discharge, 15 (38%) were discharged to a nursing facility, 12 (30%) to a rehabilitation facility and 1 (3%) to home. After a mean of 5.4 months, 1 patient had died, 11 had severe disability and 16 had moderate disability or better. Conclusion: The diagnosis of CFE is complicated by unknown sensitivity of diagnostic modalities. Nonetheless, typical MRI and ophthalmologic findings can assist in diagnosis. MES are associated with scattered infarction on MRI, suggesting active disease. The outcome of patients with CFE is highly variable, and a better understanding of this potentially devastating disease will require studies with larger numbers of cases collected in a standard fashion at multiple trauma centers.

Abstract WMP46: Frequency of High-Risk Features and Stroke Risk in Asymptomatic Carotid Atherosclerosis: Systematic Review and Meta-Analysis

Background: The recommended treatment of asymptomatic carotid atherosclerosis is best medical therapy since the 1% annual risk of stroke is lower than the risk of stroke from revascularization. Specific imaging features may identify patients at increased risk of stroke and optimize the risk-benefit ratio of carotid surgery. To assess the relevance and feasibility of such approach, we aimed to summarize available data on the frequency of high-risk features and the related risk of stroke in patients with asymptomatic carotid atherosclerosis. Methods: A search of Pubmed and Ovid-Embase identified prospective studies reporting findings of carotid plaque imaging and incidence of stroke in patients with asymptomatic carotid atherosclerosis. Prevalence of high-risk features and incidence of ipsilateral ischemic events were pooled using random-effect meta-analysis. Results: Thirty-five studies enrolling 5808 participants with asymptomatic carotid atherosclerosis of various grades were included. The pooled prevalence (95% CI) of high-risk features on plaque imaging was 28.8 (18.8 - 38.7). The prevalence of neovascularization was 53.5% (45.2 - 61.8), echolucency 40.0% (30.8 - 49.6), lipid-rich necrotic core 35.7% (24.1 - 48.1), thin or ruptured fibrous cap 27.5% (14.2 - 43.3), silent brain infarcts 27.0% (15.3 - 40.5), impaired cerebrovascular reserve 25.9% (10.3 - 45.5), intraplaque hemorrhage 19.2% (13.9 - 25.1), microembolic signals 14.4% (8.9 - 20.8), and ulceration 13.5% (1.3 - 34.0). In 15 cohort studies enrolling 4215 participants, the mean duration of follow-up was 3.5 years (2.0 - 4.6). The pooled incidence of ipsilateral ischemic events was 2.7 per 100 person-years (1.6 - 4.0). This incidence was higher in patients with a high-risk feature (4.9%, 2.3 - 8.2) than in those without (0.9%, 0.2 - 1.8) with an odds ratio of 4.6 (2.3 - 9.3). Conclusion: High-risk features on imaging are frequent in asymptomatic carotid atherosclerosis and associated with a fourfold increase in the annual risk of ipsilateral ischemic events. A risk-oriented selection of patients with asymptomatic carotid atherosclerosis prior to randomization in revascularization trials appears relevant and may be a strategy to prevent stroke in asymptomatic carotid atherosclerosis.

Carotid Wallstent Versus Roadsaver Stent and Distal Versus Proximal Protection on Cerebral Microembolization During Carotid Artery Stenting

ObjectivesThe aim of this study was to randomly compare the double-layer Roadsaver stent (RS) (Terumo, Tokyo, Japan) with the single-layer Carotid Wallstent (CW) (Boston Scientific, Santa Clara, California) in association with either distal embolic protection with the FilterWire (FW) device (Boston Scientific) or proximal protection with the Mo.Ma Ultra device (Medtronic, Santa Rosa, California) in patients with lipid-rich carotid plaques. BackgroundThe role of both stent type and brain protection during carotid artery stenting (CAS) remains unsettled. MethodsA total of 104 consecutive patients with carotid artery stenosis were randomized to CAS with FW + RS (group 1, n = 27), FW + CW (group 2, n = 25), Mo.Ma + RS (group 3, n = 27), or Mo.Ma + CW (group 4, n = 25). The primary endpoint was the number of microembolic signals (MES) on transcranial Doppler among groups in the following CAS steps: 1 and 2) target vessel access; 3) lesion wiring; 4) pre-dilation; 5) stent crossing; 6) stent deployment; 7) stent dilation; and 8) device retrieval and deflation. ResultsNo significant differences in baseline characteristics were found among the 4 groups. Compared with the FW device, the Mo.Ma Ultra device significantly reduced mean MES count (p < 0.0001) during lesion crossing, stent crossing, stent deployment, and post-dilation. Compared with the CW, the RS significantly reduced MES count (p = 0.016) in steps 6 to 8, including spontaneous MES (29% of patients). The combination of Mo.Ma + RS performed significantly better than Mo.Ma + CW (p = 0.043). Clinical major adverse cardiac and cerebrovascular events occurred in 3 patients (p = 0.51). After CAS, peak systolic velocity significantly decreased in all patients. In-stent restenosis developed in 1 patient (0.98%) at 6-month follow-up. The RS was an independent predictor of external carotid artery patency over time. ConclusionsIn patients with high-risk, lipid-rich plaque undergoing CAS, Mo.Ma + RS led to the lowest microembolic signals count. (Role of the Type of Carotid Stent and Cerebral Protection on Cerebral Microembolization During Carotid Artery Stenting. A Randomized Study Comparing Carotid Wallstent vs Roadsaver® Stent and Distal vs Proximal Protection; NCT02915328)

Diagnostic Accuracy of Carotid Doppler Ultrasound for the Detection of Right-to-Left Cardiac Shunt.

Background:Right-to-left cardiac shunt is a condition anatomically related to patent foramen ovale (PFO) and potentially related to cryptogenic cerebrovascular events. As recent studies demonstrated a reduction of recurrent stroke in patients undergoing percutaneous PFO closure after a cryptogenic cerebrovascular event, it is now of pivotal importance to screen these patients for Right-to-left shunt(RLS) presence. At this regard, transcranial color Doppler (TCCD) with contrast has a good sensitivity (97%) and specificity (93%) compared to transesophageal echocardiography and became the test of choice to assess RLS presence, thanks to its noninvasive nature. However, temporal bone window is not accessible in 6%–20% patients. Several approaches have been explored to overcome this limitation with encouraging but not definitive results for extracranial internal carotid artery (ICA) approach, proposed in previous pivotal studies. Aims of this study were to further assess the diagnostic accuracy of ICA Doppler ultrasound with contrast for RLS detection compared to TCCD, with the two tests performed simultaneously.Materials and Methods:Sixty-four patients underwent simultaneously to TCCD and ICA Doppler ultrasound, both performed at rest and after Valsalva maneuver. Diagnosis of RLS was made, both for TCCD and ICA ultrasound, if=1 microembolic signals (MES) were detected during the examination (either at rest or after Valsalva maneuver).Results:ICA Doppler ultrasound sensitivity and specificity resulted respectively of 97% (confidence interval [CI] 95%) and 100% ([CI] 95%), while negative likelihood ratio was 0.03 (CI 95%).Conclusions:ICA Doppler ultrasound represents a valid alternative to TCCD for RLS screening in patients without adequate transcranial acoustic window.

Cerebral microembolism during atrial fibrillation ablation can result from the technical aspects and mostly does not cause permanent neurological deficit.

IntroductionAtrial fibrillation ablation can be associated with microembolism detected in the intracranial arteries and risk of neurological incidents. The aims of this study were to evaluate microembolic signals (MES) during pulmonary vein isolation (PVI) and establish the potential significance of MES for damage of the brain in radiological investigation and neurological state.Material and methodsIn the prospective study we included patients with atrial fibrillation undergoing percutaneous pulmonary vein isolation (radiofrequency ablation/balloon cryoablation) with ultrasound monitoring of microembolisms in the middle cerebral artery. Neurological examination and MRI of the head were performed in all participants.ResultsThe study enrolled 80 patients at a mean age of 58 years. Microembolisms during the monitoring of the flow in the right middle cerebral artery were recorded in 61 (76.3%) patients in the amount of 51–489 (mean: 239). Most often the microembolic signals were registered during the trans-septal puncture and the stage of ablation. In 89%, microembolisms were gaseous. Mean score on the Fazekas scale for the whole group before ablation: 0.87 ±0.7 (0–3, med. 1); after: 0.93 ±0.71. In 3 (4.3%) patients the lesions worsened during the follow-up period. None of the patients revealed a cardiovascular event during the follow-up period and no changes were observed in the neurological status.ConclusionsThe majority of cerebral microembolisms generated during PVI are gaseous in nature. The cerebral microembolisms associated with PVI probably result from the technical aspects of the procedure and do not cause either permanent brain damage in the radiological investigation or neurological deficit.

The applications of transcranial Doppler in ischemic stroke.

This overview provides a summary of the applications of transcranial Doppler (TCD) in ischemic stroke. A fast-track neurovascular ultrasound protocol has been developed for detecting occlusion or stenosis. The technique is more reliable in the carotid area than in the posterior circulation. By monitoring the pulsatility index the in-crea-sed intracranial pressure can be diagnosed. TIBI score was developed for grading residual flow. TCD has been shown to accurately predict complete or any recanalization. Regarding recanalization, TCD has a sensitivity of 92%, a specificity of 88%, a positive predictive value of 96%, a negative predictive value of 78% and an overall accuracy of 91%, respectively. Sonothrombolysis seemed to be a promising application but randomized controlled trials have shown that it does not improve clinical outcome. TCD examination can detect microembolic signals (MES) which are associated with an increased risk of stroke. Micro-em-boli were detected in symptomatic and asymptomatic carotid artery stenosis and during carotid endarterectomy. The number of microemboli can be decreased by antithrombotic therapy. Contrast en-chan-ced examination and Valsalva maneuver with continuous TCD monitoring can accurately screen for right-to-left shunt.

Detection of microembolic signals before and after stent treatment of patients with carotid stenosis and determination of related factors

Detection of microembolic signals before and after stent treatment of patients with carotid stenosis and determination of related factors