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

OBJECTIVES: Cerebral 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 METHODS: Patients 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. RESULTS: We 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. CONCLUSIONS: Microembolic 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-URL: http://www. CLINICALTRIALS: gov. Unique identifier: NCT03543319.

Evaluation of microembolic signals on carotid ultrasound during pulmonary vein isolation with high-power short-duration and cryoballoon ablations: When and where do bubble and solid emboli arise?

INTRODUCTION: The underlying risks of asymptomatic embolization during high-power short-duration (HPSD) ablation for atrial fibrillation remain unclear. We aimed to evaluate microembolic signals (MESs) during HPSD ablation with power settings of 50 and 90 W in comparison with those during cryoballoon (CB) ablation using a novel carotid ultrasound-Doppler system that classifies solid and air bubble signals using real-time monitoring. METHODS AND RESULTS: Forty-seven patients underwent HPSD ablation using radiofrequency (RF), and 13 underwent CB ablation. MESs were evaluated using a novel pastable soft ultrasound probe equipped with a carotid ultrasound during pulmonary vein isolation. We compared the detailed MESs and their timing between RF and CB ablations. The number of MESs and solid signals were significantly higher in the RF group than in CB group (209 ± 229 vs. 79 ± 32, p = .047, and 83 ± 89 vs. 28 ± 17, p = .032, respectively). In RF ablation, the number of MESs, solid, and bubble signals per ablation point, or per second, was significantly higher at 90 W than at 50 W ablation. The MESs, solid, and bubble signals were detected more frequently in the bottom and anterior walls of the left pulmonary vein (LPV) ablation. In contrast, many MESs were observed before the first CB application and decreased chronologically as the procedure progressed. Signals were more prevalent during the CB interval rather than during the freezing time. Among the 28 patients, 4 exhibited a high-intensity area on postbrain magnetic resonance imaging (MRI). The MRI-positive group showed a trend of larger signal sizes than did the MRI-negative group. CONCLUSION: The number of MESs was higher in the HPSD RF group than in the CB group, with this risk being more pronounced in the 90 W ablation group. The primary detection site was the anterior wall of the LPV in RF and the first interval in CB ablation.

Cognitive changes associated with cerebral emboli during coronary intervention.

OBJECTIVE: To investigate factors influencing the frequency and type of microembolic signals (MES) detected using transcranial Doppler (TCD) in patients undergoing elective coronary intervention, and to correlate MES with silent stroke detected using magnetic resonance imaging (MRI) and cognitive dysfunction. METHODS: The subset study of a randomized clinical trial was conducted on 70 patients (58 males; mean age 59.9 ± 8.4 years) who underwent bilateral TCD monitoring of middle cerebral arteries (MCAs) during elective coronary interventions. Neurologic examination and brain MRI were performed prior to, and 24 h post­intervention. Cognitive function tests were performed prior to, and on day 30 post­intervention. RESULTS: The incidence of detected MES was 94.3 %. Eighteen (25.7 %) patients had new clinically asymptomatic ischemic lesions on MRI. The number of solid MES negatively correlated with changes in revised Addenbrooke's Cognitive Examination test (ACE-R) and, the number of solid MES and combinations of solid and gaseous MES negatively correlated with changes in Mini Mental­State Examination (MMSE) conducted on day 30 after the intervention (p < 0.05 in all cases). CONCLUSION: Cardiac catheterization was associated with a high risk of cerebral embolism in our patients. A higher number of solid MES and combinations of solid and gaseous MES was associated with the deterioration in cognitive tests (Tab. 5, Fig. 3, Ref. 30).

Microembolic signal monitoring in patients with HeartMate 3 and HeartWare left ventricular assist devices: Association with antithrombotic treatment and cerebrovascular events.

BACKGROUND: In patients with left ventricular assist devices (LVADs), ischemic and hemorrhagic stroke are dreaded complications. Predictive markers for these events are lacking. This study aimed to investigate the prevalence and predictive value of microembolic signals (MES) for stroke, detected by Transcranial Doppler sonography (TCD) in patients with HeartMate 3 (HM 3) or HeartWare (HW). METHODS: A thirty-minute bilateral TCD monitoring of the middle cerebral artery (MCA) was performed in 62 outpatients with LVAD (HM 3 N = 31, HW N = 31) and 31 healthy controls. Prevalence and quantity of MES were investigated regarding clinical and laboratory parameters. Cerebrovascular events (CVE) were recorded on follow-up at 90 and 180 days. RESULTS: MES were detected in six patients with HM 3, three patients with HW, and three controls. Within the LVAD groups, patients on monotherapy with vitamin-K-antagonist (VKA) without antiplatelet therapy were at risk for a higher count of MES (negative binomial regression: VKA: 1; VKA + ASA: Exp(B) = 0.005, 95%CI 0.001-0.044; VKA + clopidogrel: Exp(B) = 0.012, 95%CI 0.002-0.056). There was no association between the presence of MES and CVE or death on follow-up (p > 0.05). CONCLUSION: For the first time, the prevalence of MES was prospectively investigated in a notable outpatient cohort of patients with HM 3 and HW. Despite optimized properties of the latest LVAD, MES remain detectable depending on antithrombotic therapy. No association between MES and CVE could be detected.

Cerebral fat embolism syndrome at a single trauma center.

OBJECTIVES: Based on a 16-year case series, we sought lessons about diagnosis and treatment of cerebral fat embolism syndrome. MATERIALS AND METHODS: Using discharge codes at a Level 1 Trauma Center, we performed a retrospective chart review of clinical characteristics, diagnostic studies, treatments, and outcome in cerebral fat embolism syndrome. RESULTS: Thirty-nine (40%) of 97 patients with fat embolism syndrome were diagnosed with cerebral fat embolism syndrome, with 29 (74%) presenting with coma. All had abnormal brain magnetic resonance imaging, with scattered cytotoxic edema (starfield pattern) in 29 (74%). All but two of the 21 patients with dilated fundoscopy showed retinal embolism. Among 29 patients with transcranial Doppler, the presence of microembolic signals in 15 (52%) was associated with fever (p = 0.039), right-to-left intracardiac shunting (p = 0.046) and a trend towards initial coma. In 11 patients with serial transcranial Dopplers and treatment with high-intensity statin therapy, the frequency of microembolic signals tended to decrease after therapy was initiated. Of the 28 (72%) of the 39 patients discharged, 16 (57%) had mild to moderate disability at last follow up. CONCLUSIONS: The recognition of cerebral fat embolism syndrome may be improved with routine inclusion of brain magnetic resonance imaging, dilated fundoscopy, and transcranial Doppler. We share our empiric management algorithm for cerebral fat embolism syndrome using these studies and with consideration of experimental therapies in select patients to prevent ongoing cerebral injury.

Microembolic signals and antiplatelet therapy in Moyamoya angiopathy.

BACKGROUND: 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. PATIENTS AND METHODS: 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 30 min 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. RESULTS: 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. CONCLUSION: 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.

BACKGROUND: 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). OBJECTIVE AND METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

The Prevalence of Microembolic Signals in Transcranial Doppler Sonography With Bubble Test in Acute Ischemic Stroke.

OBJECTIVES: Transcranial Doppler ultrasound (TCD) is noninvasive and highly sensitive and specific for the diagnosis of patent foramen ovale (PFO). We evaluated the diagnostic implications of the TCD with a saline agitation test as a routine work-up for ischemic stroke patients. METHODS: A TCD bubble study was performed in all consecutive ischemic stroke patients as a routine work-up. We evaluated the prevalence of microembolic signals (MES) for each stroke etiology and the optimal number of MES for predicting the PFO-attributable stroke. RESULTS: Subjects (N = 499) with acute ischemic stroke were enrolled. A significant fraction of patients had MES during both normal respiration (5.7-44.4%) and the Valsalva maneuver (19.5-55.6%) across all stroke etiology categories. The optimal MES threshold for the diagnosis of PFO-attributable stroke confirmed by transesophageal echocardiography was 46 MES during the Valsalva maneuver (96% sensitivity and 95% specificity). Applying ≥46 MES during the Valsalva maneuver as a threshold effectively increased the ability to differentially diagnose PFO-attributable stroke from other etiologies. The number of MES during the Valsalva maneuver was negatively correlated with increasing age (r = -.108; P = .016). CONCLUSIONS: A significant fraction of patients had right to left shunt across all Trial of ORG 10172 in Acute Stroke Treatment etiologies. A threshold number of MES facilitated the differential diagnosis of PFO-attributable stroke from other etiologies, and the optimal threshold was 46 MES during the Valsalva maneuver.

The Course of Carotid Plaque Vulnerability Assessed by Advanced Neurosonology.

Background: Carotid artery atherosclerosis is a major risk factor for ischemic stroke. This risk is related to plaque vulnerability and is characterized by plaque morphology, intraplaque neovascularization, and cerebral microembolization. Advanced neurosonology can identify vulnerable plaques and aid in preventing subsequent stroke. We aimed to assess the time course of cerebral microembolization and intraplaque neovascularization during 6 months of follow-up and to explore the utility of advanced neurosonology in patients with acute cerebral ischemia. Methods: Fifteen patients with acute cerebral ischemia and carotid artery plaques underwent comprehensive extra- and intracranial ultrasound examinations, including microemboli detection and contrast-enhanced ultrasound. The examinations were repeated after 3 and 6 months. Results: We examined 28 plaques in 15 patients. The ultrasonographic features of plaque vulnerability were frequent in symptomatic and asymptomatic plaques. There were no significant differences in stenosis degree, plaque composition, plaque surface, neovascularization, or cerebral microembolization between symptomatic and asymptomatic plaques, but symptomatic plaques had a higher number of vulnerable features. None of the patients had recurrent clinical stroke or transient ischemic attack during the follow-up period. We observed a decrease in cerebral microembolization at 6 months, but no significant change in intraplaque neovascularization. Conclusions: In patients with acute cerebral ischemia and carotid artery plaques, cerebral microembolization decreased during 6 months of follow-up, indicating plaque stabilization. Clinical Trial Registration:ClinicalTrial.gov, identifier NCT02759653.

Intracranial microembolic signals might be a potential risk factor for cognitive impairment.

Objective: We aimed to explore the relationship between microembolic signals (MES) and cognitive impairment in patients with neurological disorders using a 30-minute MES monitoring test.Methods: We retrospectively reviewed patients who visited outpatient departments and underwent a 30-minute MES monitoring session using dual-channel transcranial doppler (TCD) at Beijing Tiantan hospital between July 2016 and December 2018. All patients completed the Montreal Cognitive Assessment (MoCA) and underwent magnetic resonance imaging (MRI). Cognitive impairment was defined as a MoCA score of less than 26. MES were identified according to the criteria of the International Consensus Group on Microembolus Detection.Results: Of the 1356 subjects who underwent MES monitoring, 159 patients (including 50 cases of MES positive and 109 cases of MES negative) had both analyzable MES monitoring recording and cognition evaluation data, of which 72 had cognitive impairment. Compared with the group with no deficits in cognitive function, the proportion of MES positive was significantly higher in patients with impaired cognitive function - that is, 47% (34/72) versus 18.4% (16/87), respectively, with p < 0.05. In multivariate logistic regression analysis, MES were independently associated with lower MoCA score (odd ratios (OR), 7.36; 95% confidence intervals (CI), 2.72-19.85, P < 0.0001).Conclusions: In this retrospective study, we found a possible correlation and relationship between MES and cognitive impairment. Further studies are required to determine whether continuous cerebral microembolization to the brain will lead to progressive cognitive impairment.

Comparison of clinical and biological differences between patent foramen ovale subtypes in ischemic stroke.

BACKGROUNDS: The patent foramen ovale (PFO) is an atrial septal tunnel with a flap-like opening, causing a right-to-left shunt (RLS) between the atrial chambers. There are few studies on ischemic stroke characteristics based on PFO subtypes. In this study, we investigated whether there are differences in clinical characteristics, RLS amount, and the etiology of stroke defined by the Trial of ORG 10,172 in Acute Stroke Treatment (TOAST) classification between PFO subtypes. METHODS: We retrospectively analyzed consecutive ischemic stroke patients with PFO who were admitted to the Jeonbuk National University Hospital from November 2013 to February 2015, and performed a microbubble test to detect RLS. The patients were divided into two groups according to RLS characteristics: constant RLS group and provoked RLS group. We compared the clinical characteristics and degree of RLS between the PFO subtypes. RESULTS: Out of 144 ischemic patients evaluated in this study, 83 (58%) were classified into the constant RLS group and 61 (42%) into the provoked RLS group. The proportion of microembolic signal (MES) grades 3 and 4 was significantly higher in the constant RLS group than in the provoked RLS group. There were no statistical differences in the distribution of TOAST classification between the two groups. CONCLUSION: The constant RLS group showed a higher proportion of high-grade MES than the provoked RLS group.

Superb Microvascular Imaging Ultrasound for Cervical Carotid Artery Stenosis for Prediction of the Development of Microembolic Signals on Transcranial Doppler during Carotid Exposure in Endarterectomy.

INTRODUCTION: During exposure of the carotid arteries, embolism from the surgical site is recognized as a primary cause of neurological deficits or new cerebral ischemic lesions following carotid endarterectomy (CEA), and associations have been reported between histological neovascularization in the carotid plaque and both plaque vulnerability and the development of artery-to-artery embolism. Superb microvascular imaging (SMI) enables accurate visualization of neovessels in the carotid plaque without the use of intravenous contrast. This study aimed to determine whether preoperative SMI ultrasound for cervical carotid artery stenosis predicts the development of microembolic signals (MES) on transcranial Doppler (TCD) during exposure of the carotid arteries in CEA. METHODS: Preoperative cervical carotid artery SMI ultrasound followed by CEA under TCD monitoring of MES in the ipsilateral middle cerebral artery was conducted in 70 patients previously diagnosed with internal carotid artery stenosis (defined as ≥70%). First, observers visually identified intraplaque microvascular flow (IMVF) signals as moving enhancements located near the surface of the carotid plaque within the plaque on SMI ultrasonograms. Next, regions of interest (ROI) were manually placed at the identified IMVF signals (or at arbitrary places within the plaque when no IMVF signals were identified within the carotid plaque) and the carotid lumen, and time-intensity curves of the IMVF signal and lumen ROI were generated. Ten heartbeat cycles of both time-intensity curves were segmented into each heartbeat cycle based on gated electrocardiogram findings and averaged with respect to the IMVF signal and lumen ROI. The difference between the maximum and minimum intensities (ID) was calculated based on the averaged IMVF signal (IDIMVF) and lumen (IDl) curves. Finally, the ratio of IDIMVF to IDl was calculated. RESULTS: MES during exposure of the carotid arteries were detected in 17 patients (24%). The incidence of identification of IMVF signals was significantly greater in patients with MES (94%) than in those without (57%; p = 0.0067). The IDIMVF/IDl ratio was significantly greater in patients with MES (0.108 ± 0.120) than in those without (0.017 ± 0.042; p < 0.0001). The specificity and positive predictive value for the IDIMVF/IDl ratio for prediction of the development of MES were significantly higher than those for the identification of IMVF signals. Logistic regression analysis revealed that only the IDIMVF/IDl ratio was significantly associated with the development of MES (95% CI 101.1-3,628.9; p = 0.0048). CONCLUSION: Preoperative cervical carotid artery SMI ultrasound predicts the development of MES on TCD during exposure of the carotid arteries in CEA.

Cerebral microemboli in mini-sternotomy compared to mini- thoracotomy for aortic valve replacement: a cross sectional cohort study.

BACKGROUND: Recently adopted mini-thoracotomy approach for surgical aortic valve replacement has shown benefits such as reduced pain and shorter recovery, compared to more conventional mini-sternotomy access. However, whether limited exposure of the heart and ascending aorta resulting from an incision in the second intercostal space may lead to increased intraoperative cerebral embolization and more prominent postoperative neurologic decline, remains inconclusive. The aim of our study was to assess potential neurological complications after two different minimal invasive surgical techniques for aortic valve replacement by measuring cerebral microembolic signal during surgery and by follow-up cognitive evaluation. METHODS: Trans-cranial Doppler was used for microembolic signal detection during aortic valve replacement performed via mini-sternotomy and mini-thoracotomy. Patients were evaluated using Addenbrooke's Cognitive Examination Revised Test before and 30 days after surgical procedure. RESULTS: A total of 60 patients were recruited in the study. In 52 patients, transcranial Doppler was feasible. Of those, 25 underwent mini-sternotomy and 27 had mini-thoracotomy. There were no differences between groups with respect to sex, NYHA class distribution, Euroscore II or aortic valve area. Patients in mini-sternotomy group were younger (60.8 ± 14.4 vs.72 ± 5.84, p = 0.003), heavier (85.2 ± 12.4 vs.72.5 ± 12.9, p = 0.002) and had higher body surface area (1.98 ± 0.167 vs. 1.83 ± 0.178, p = 0.006). Surgery duration was longer in mini-sternotomy group compared to mini-thoracotomy (158 ± 24 vs. 134 ± 30 min, p < 0.001, respectively). There were no differences between groups in microembolic load, length of ICU or total hospital stay. Total microembolic signals count was correlated with cardiopulmonary bypass duration (5.64, 95%CI 0.677-10.60, p = 0.027). Addenbrooke's Cognitive Examination Revised Test score decreased equivalently in both groups (p = 0.630) (MS: 85.2 ± 9.6 vs. 82.9 ± 11.4, p = 0.012; MT: 85.2 ± 9.6 vs. 81.3 ± 8.8, p = 0.001). CONCLUSION: There is no difference in microembolic load between the groups. Total intraoperative microembolic signals count was associated with cardiopulmonary bypass duration. Age, but not micorembolic signals load, was associated with postoperative neurologic decline. TRIAL REGISTRY NUMBER: clinicaltrials.gov , NCT02697786 14.

[Floating structure of the carotid artery as a cause of microembolism in the basin of cerebral arteries]. / Flotiruiushchaia struktura sonnoi arterii kak prichina mikroémbolii v basseine mozgovykh arterii.

This article describes a rare clinical and diagnostic case report regarding a female patient presenting with frequent transitory attacks in the basin of both middle cerebral arteries. Based on the findings of duplex scanning of the cervical arteries we revealed floating structures with the presence of pronounced slow turbulent blood flow. After excluding all known causes of cerebral artery microembolism, associated with heart pathology or with the presence of unstable atherosclerotic plaques, the leading hypothesis of transitory ischaemic attacks in the woman concerned was the formation of microthrombi in the zone of motility of the structures revealed. The results of bitemporal transcranial Doppler monitoring carried out during 30 minutes detected more than 10 microembolic signals in the middle cerebral artery, thus confirming the embolic nature of transitory ischaemic attacks.

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

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.

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

INTRODUCTION: Atrial 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 METHODS: In 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. RESULTS: The 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. CONCLUSIONS: The 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.

Transcranial Doppler Emboli Monitoring for Infective Endocarditis.

BACKGROUND AND PURPOSE: Ischemic stroke can occur in 20-55% of patients with infective endocarditis (IE) with 75% occurring during the first 2 weeks of treatment. CT or MRI brain can diagnose the sequelae of stroke but transcranial Doppler (TCD) can document active embolization. We undertook a retrospective review of our patient cohort and a systematic review of literature to assess the role of TCD in early diagnosis and management of ischemic stroke in IE. METHODS: Retrospective chart review and literature review. RESULTS: We found 89 patients with stroke caused by IE at our institution from December 2011 to April 2018. TCDs were obtained on 26 patients; 16 were abnormal for cerebrovascular abnormalities. Only 4 patients had 30-minute emboli monitoring performed, of which one revealed emboli. We found 3 studies investigating the role of TCDs in IE that showed promise in its use as a predictive tool in stroke risk stratification. CONCLUSIONS: Presence of embolization in the form of high-intensity transient signals (HITS) detected on TCDs can be used for early diagnosis of IE, assessing efficacy of antibiotic therapy, and stratification of stroke risk in IE. This can aid further research into testing preventative interventions for reducing stroke burden in IE such as earlier valvular surgery or vacuum-assisted vegetation extraction.

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

OBJECTIVES: The 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. BACKGROUND: The role of both stent type and brain protection during carotid artery stenting (CAS) remains unsettled. METHODS: A 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. RESULTS: No 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. CONCLUSIONS: In 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).

Cerebral Microembolization in Left Ventricular Assist Device Associated Ischemic Events.

INTRODUCTION: The 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. METHODS: We 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. RESULTS: Of 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. CONCLUSIONS: LVAD 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.

Prevalence of Microembolic Signals in Embolic Stroke of Undetermined Source and Other Subtypes of Ischemic Stroke.

Background and Purpose- Embolic stroke of undetermined source (ESUS) has been proposed to cause thromboembolic infarction from unknown but potential embolic sources. However, an embolus remains undetected in ESUS. The goal of this study was to characterize the prevalence and risk factors of microembolic signals (MESs) in ESUS. Methods- We examined 108 patients with acute ischemic stroke in the internal carotid artery territory or transient ischemic attack within 14 days of symptom onset and who were admitted to our hospital between April 2017 and March 2019. MESs were monitored in the middle cerebral artery on transcranial Doppler for 60 minutes. We examined the prevalence and number of MES in ESUS and other stroke subtypes, such as cardioembolism, large artery atherosclerosis, cerebral small vessel disease, and transient ischemic attack. The present study was registered in University Hospital Medical Information Network Clinical Trials Registry (UMIN000031913). Results- MESs were detected in 33 (31%) of 108 patients. ESUS showed the highest proportion (12/24 [50%]), followed by large artery atherosclerosis (8/20 [40%]), cardioembolism (6/18 [33%]), transient ischemic attack (4/24 [17%]), and cerebral small vessel disease (3/21 [14%]). Univariate analysis showed that higher systolic blood pressure, body mass index, hemoglobin A1c, and ESUS were significantly associated with MES. In multiple logistic regression analysis, ESUS remained significantly associated with MES after adjustment for described covariates from univariate analysis (odds ratio, 2.86 [95% CI, 1.01-8.08]). Conclusions- This study demonstrated significant association of ESUS with MES, supporting the embolic nature of this stroke subtype. Registration- URL: https://upload.umin.ac.jp. Unique identifier: UMIN000031913.