Prognostic Role of Microembolic Signals After Endovascular Treatment in Anterior Circulation Ischemic Stroke Patients

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

INTRODUCTION

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.

PATIENTS AND METHODS

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.

RESULTS

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.

CONCLUSIONS

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).

Point-of-Care Ultrasound in Neurology - Report of the EAN SPN/ESNCH/ERcNsono Neuro-POCUS Working Group

In the last decade, ultrasound examination in neurology has been undergoing a significant expansion of its modalities. In parallel, there is an increasing demand for rapid and high-quality diagnostics in various acute diseases in the prehospital setting, the emergency room, intensive care unit, and during surgical or interventional procedures. Due to the growing need for rapid answers to clinical questions, there is particular demand for diagnostic ultrasound imaging. The Neuro-POCUS working group, a joint project by the European Academy of Neurology Scientific Panel Neurosonology, the European Society of Neurosonology and Cerebral Hemodynamics, and the European Reference Centers in Neurosonology (EAN SPN/ESNCH/ERcNsono Neuro-POCUS working group), was given the task of creating a concept for point-of-care ultrasound in neurology called "Neuro-POCUS". We introduce here a new ultrasound examination concept called point-of-care ultrasound in neurology (Neuro-POCUS) designed to streamline conclusive imaging outside of the ultrasound center, directly at the bedside. The aim of this study is to encourage neurologists to add quick and disease-oriented Neuro-POCUS to accompany the patient in the critical phase as an adjunct not a substitution for computed tomography, magnetic resonance imaging, or standard comprehensive neurosonology examination. Another goal is to avoid unwanted complications during imaging-free periods, ultimately resulting in advantages for the patient.

The intensive care management of acute ischaemic stroke

PURPOSE OF REVIEW

To discuss recent advances in the critical care management of acute ischaemic stroke patients and highlight controversies and consensus.

RECENT FINDINGS

Intravenous thrombolysis and endovascular thrombectomy are standard of care reperfusion therapies that have revolutionized the management of acute ischaemic stroke and transformed outcomes for patients. They can now be delivered in extended time windows and to those previously ineligible for intervention based on advanced neuroimaging criteria. Secondary systemic insults, such as hypo- and hypertension, hyperthermia or hyperglycaemia, which can extend the area of ischaemia must also be prevented or corrected to minimize infarct progression. Meticulous blood pressure management is of central importance, particularly in patients that have undergone reperfusion therapies. Neurological deterioration can occur because of infarct extension, haemorrhagic transformation or worsening cerebral oedema. Transcranial Doppler ultrasonography allows bedside, noninvasive evaluation of cerebral haemodynamics and is increasingly used in acute stroke triage, management and recovery prediction. The management of acute ischaemic stroke raises several ethical issues, and shared decision making is essential to ensure outcomes that are compatible with an individual patient's expectations.

SUMMARY

A bundle of medical, endovascular and surgical strategies implemented by a multidisciplinary team working to locally agreed protocols can improve long-term stroke outcomes.

Quantitative 3D analysis of tissue damage in a rat model of microembolization

There is a discrepancy between successful recanalization and good clinical outcome after endovascular treatment (EVT) in acute ischemic stroke patients. During removal of a thrombus, a shower of microemboli may release and lodge to the distal circulation. The objective of this study was to determine the extent of damage on brain tissue caused by microemboli. In a rat model of microembolization, a mixture of microsphere (MS) sizes (15, 25 and 50 µm diameter) was injected via the left internal carotid artery. A 3D image of the left hemisphere was reconstructed and a point-pattern spatial analysis was applied based on G- and K-functions to unravel the spatial correlation between MS and the induced hypoxia or infarction. We show a spatial correlation between MS and hypoxia or infarction spreading up to a distance of 1000-1500 µm. These results imply that microemboli, which individually may not always be harmful, can interact and result in local areas of hypoxia or even infarction when lodged in large numbers.

Trans-cranial Doppler predicts early neurologic deterioration in anterior circulation ischemic stroke after successful endovascular treatment

Background

Early neurologic deterioration (END) may occur in patients with anterior circulation ischemic stroke (ACIS) after receiving endovascular treatment (EVT). Hemodynamic insufficiency, re-occlusion, and post-re-canalization hyper-perfusion are likely to play a critical role in END. We hypothesized that hemodynamic changes can predict END in patients with ACIS post-successful EVT using trans-cranial Doppler (TCD).

Methods

We utilized a prospectively maintained database of ACIS patients treated with EVT between September 2016 and June 2018 in the Xuanwu Hospital, Capital Medical University. TCD parameters including peak systolic velocity (PSV), bilateral mean flow velocity (MFV), and pulse index (PI) were determined via the middle cerebral arteries within 72 h post-EVT. A logistic regression model was applied to detect independent predictors for END.

Results

Totally, 112 EVT patients were included in this study and 80/112 patients experienced successful re-canalization with <50% residual stenosis, while 17/80 (21.3%) patients suffered END, for which vasogenic cerebral edema (11/17) was considered as a leading role and followed by symptomatic intra-cranial hemorrhage (4/17) and ischemia progression (2/17). For the 80 patients, the PSV (median: 127 cm/s vs. 116 cm/s, P = 0.039), the ratio of ipsilateral-MFV/contra-lateral-MFV (iMFV/cMFV) (median: 1.29 vs. 1.02, P = 0.036) and iMFV/mean blood pressure (MBP) (median: 0.97 vs. 0.79, P = 0.008) in END patients were higher than those of non-END. Using the receiver-operating characteristic curve to obtain cut-off values for PSV, PI, iMFV/cMFV, and iMFV/MBP for END, we found that PI ≥0.85 (odds ratio: 11.03, 95% confidence interval: 1.92–63.46, P = 0.007) and iMFV/MBP ≥0.84 (odds ratio: 9.20, 95% confidence interval: 2.07–40.84, P = 0.004) were independent predictors of END in a multivariate logistic regression model, with a sensitivity of 82.4% and 76.5% and a specificity of 42.9% and 66.7%, respectively, and had the positive predictive values of 29.0% and 38.2%, and negative predictive values of 90.0% and 91.3%, with an area under the receiver-operating characteristic curve of 0.57 and 0.71, respectively.

Conclusion

TCD examination of EVT patients may be used as a real-time tool to detect END predictors, such as the higher PI and iMFV/MBP, allowing for better post-thrombectomy management in ACIS patients.

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

BACKGROUND AND PURPOSE

Although transcranial Doppler detects microembolic signals (MES) in numerous settings, the practical significance of such findings remains unclear.

METHODS

Clinical information from ischemic stroke or transient ischemic attack patients (n = 248) who underwent embolic monitoring from January 2015 to December 2018 was obtained.

RESULTS

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).

CONCLUSIONS

MES may help to risk stratify patients as their presence is associated with ischemic recurrence and worse outcomes.

Microemboli After Successful Thrombectomy Do Not Affect Outcome but Predict New Embolic Events

Background and Purpose- We aimed to determine if microemboli after endovascular thrombectomy correlate with unfavorable outcomes despite successful recanalization. Methods- This is a prospective multicenter study of consecutive patients with ischemic stroke and occlusion of anterior circulation vessels (terminal internal carotid or main trunk of the middle cerebral artery/first-order branch of the main trunk of the middle cerebral artery segments of middle cerebral artery) after successful thrombectomy (modified Treatment In Cerebral Ischemia grades 2b-3). Microembolic signals (MES) were assessed by 30 minutes of transcranial Doppler monitoring within 72 hours of the last-seen-well time. Major outcomes included modified Rankin Scale at 90 days and infarct volume on head computed tomography at 24 hours. We also assessed early outcomes based on National Institutes of Health Stroke Scale variation and recurrence of stroke, transient ischemic attack, or systemic embolism within 90 days. Results- Among 111 patients, MES were detected in 43 (39%), with a median rate of 4 counts/h (interquartile range 2-12). The occurrence of MES was not associated with a significant difference in modified Rankin Scale (ordinal shift analysis, adjusted odds ratio, 1.06 [95% CI, 0.48-2.34] P=0.85) nor in functional independence (modified Rankin Scale, 0-2: adjusted odds ratio, 0.52 [95% CI, 0.19-1.39] P=0.19). Patients with and without MES had similar infarct volumes (adjusted beta, 11.2 [95% CI, -46.6 to +22.9] P=0.51) on 24-hour computed tomography. MES did predict new embolic events (adjusted Cox hazard ratio, 6.78 [95% CI, 1.63-27.8] P=0.01). Conclusions- MES detected by transcranial Doppler following endovascular treatment of anterior circulation occlusions do not predict clinical or radiological outcome. However, such emboli are an independent marker of recurrent embolic events within 90 days.

Early hemodynamic predictors of good outcome and reperfusion injury after endovascular treatment

Objective

To find early hemodynamic predictors of outcome and reperfusion injury in patients with acute ischemic stroke due to anterior circulation large artery occlusion (LAO) after endovascular treatment (EVT).

Methods

Serial transcranial color-coded sonography examinations assessed the vessel status and cerebral hemodynamics of 185 (109 [58.9%] men, mean age 69.5 ± 12.3 years) consecutive patients with acute anterior circulation LAO soon after, at 48 hours after, and 1 week after EVT.

Results

Successful recanalization (odds ratio [OR] 0.25, 95% confidence interval [CI] 0.11–0.61) and normal peak systolic velocity (PSV) ratio (PSV of recanalized middle cerebral artery/PSV of contralateral middle cerebral artery) at 48 hours (OR 0.22, 95% CI 0.15–0.64) and after 1 week (OR 0.11, 95% CI 0.07–0.31) from EVT were independent predictors of good outcome at 3 months. Thrombectomy failure (OR 10.22, 95% CI 1.47–45.53) and pathologic PSV ratio at 1 week from EVT (OR 15.23, 95% CI 4.54–46.72) were associated with a worse 90-day outcome. Patients who subsequently developed postinterventional intracranial hemorrhage (ICH) showed a higher mean PSV ratio (3.5 ± 0.2 vs 2.4 ± 0.1, p < 0.0001) soon after successful recanalization. In multivariate analysis, early PSV ratio was independently associated with postprocedural ICH (OR 8.474, 95% CI 3.066–45.122, p < 0.01]. At 1 week from EVT, 15 of 21 (71.4%) patients with ICH who resumed normal PSV values had a better 90-day outcome (modified Rankin Scale score 0–2: 40% vs 0%).

Conclusion

Post-EVT ultrasound monitoring of stroke patients might be an effective bedside method for assessing treatment efficacy, shedding light on outcome variability and identifying patients at increased risk of ICH.