Intracranial Vessel Occlusion Research Articles

Neurothrombectomy 2022-Extension of indications and technical innovations

For advanced territorial ischemia numerous retrospective and prospective studies have shown a positive effect of mechanical thrombectomy (MT) compared to best medicinal treatment alone. For patients with minor stroke (NIHSS < 6) there is currently alack of evidence for MT. Appropriate study protocols must differentiate between patients with large vessel occlusion with disproportionately mild symptoms and more distal vascular occlusion and therefore correspondingly fewer clinical symptoms. The role of intravenous lysis treatment before MT as bridging lysis also currently retains its general recommendation, as large studies could not show a uniform noninferiority of MT alone. In addition, the use of intra-arterial lysis after successful MT offers a promising approach, which still needs to be evaluated. Novel aspiration catheters and stent-retrievers as well as competing thrombectomy techniques can be compared by the first pass effect, the successful recanalization with only one attempt at thrombectomy. Contact aspiration and stent-retriever thrombectomy under aspiration are equivalent and established thrombectomy procedures. For the latter, several detailed maneuver tactics are described for improvement of thrombectomy success. Also, in retrospective studies the combination with aballoon-guided catheter promises a further improvement of recanalization results. In the case of failure of supra-aortic vessel probing with inguinal access, radial access and direct carotid puncture are alternative access routes. Recent studies on ICA stenting with tandem occlusions showed a benefit of stents without an increased risk for symptomatic intracranial hemorrhage. The retrograde approach, to first treat the intracranial vessel occlusion and then the carotid stenosis, seems to be advantageous.

Intracranial aspergillosis in immunocompetent adult patients without risk factors: a systematic review.

The clinical features and prognostic factors of intracranial aspergillosis in immunocompetent patients without risk factors are not well known. PubMed, Scopus, Google Scholar, and Web of Science were searched for all relevant case reports/series on adult patient (≥ 18years) with aspergillosis published from 1976 to 2018. One hundred eighty-two patients (median age, 40years; range, 18-83years; male:female, 115:67) were identified. Types of intracranial aspergillosis included intracranial mass from the skull base (54.9%), pure intraparenchymal disease (23.6%), meningoencephalitis (13.2%), and dural-based mass (8.2%). Vascular complications occurred in 44 patients (26.3%). Eighty-one patients (44.5%) had favourable final clinical outcomes without any deficits, whereas 58 (31.9%) died. Disease-related mortality improved significantly over time (43.1% [28/65] before 2000, 25.9% [30/116] after 2001; p = 0.021). Patients with meningoencephalitis demonstrated the highest mortality rate (79.2%, 19/24). Medical non-responders (patients whose disease course worsened after receiving the initial medication regimen) and vascular complications (the presentation of subarachnoid haemorrhage, intracerebral haemorrhage, or infarction related to the rupture or occlusion of intracranial vessels) were significantly associated with mortality (p < 0.001). Findings from the current review may help predict patient prognosis at the initial assessment and determine potential prognostic factors.

Abstract WMP63: Artificial Intelligence Assessment Of Non-contrast Ct Increases Intracranial Occlusion Detection As Compared With Ct-angiograhy Readings

Artificial Intelligence (AI) can assist in vessel occlusion (VO) identification in acute stroke patients. We aim to investigate the impact of using an AI-based software for automated VO detection on non-contrast CT (AI-VO) as compared to CT-Aangiograpphy (CTA). Methods: From April to October 2020 all patients admitted with a suspected acute ischemic stroke underwent urgent non-contrast CT / CTA / CTP and were treated accordingly. Hypoperfusion areas defined as Tmax&gt;6s on CTP (RAPID software), congruent with the clinical symptoms and a vascular territory, were considered VO (CTP-VO: ground truth). In addition, two experienced neuroradiologists blinded to CTP but not to clinical symptoms retrospectively evaluated CT and CTA to identify intracranial VO (CTA-VO). AI-VO was automatically determined by an AI-based software (Methinks). Results: Of the 338 patients included, 157 (46.5%) showed a CTP-VO (median Tmax&gt;6s: 73[29-127]ml). Overall sensitivity to detect CTP-VO was 50.3% for CTA-VO and 66.9% for AI-VO; specificity was 97.8% for CTA-VO and 86.2% for AI-VO. EVT was performed in 103 patients (EVT-VO: 65.6% of CTP-VO; Tmax&gt;6s: 102[63-160]ml); sensitivity to detect EVT-VO was 69% for CTA-VO and 79.6% for AI-VO; specificity was 95.3% for CTA-VO and 79.6% for AI-VO. The probability to detect a CTP-VO was higher with AI than with CTA for distal occlusions (figure). Accordingly, AI-VO sensitivity was higher than CTA-VO for angiographically confirmed M2/M3-MCA occlusions (80.7% vs 34.6%; p=0.002) but not for M1-MCA/ICA occlusions (82.1% Vs 88.1%;p=0.467). Conclusion: AI-assisted vessel occlusion identification on non-contrast CT may be a useful tool in acute stroke evaluation, especially for distal VO identification, potentially increasing endovascular treatment in these cases.

Investigation of Altered Spontaneous Brain Activities in Patients With Moyamoya Disease Using Percent Amplitude of Fluctuation Method: A Resting-State Functional MRI Study.

Background: Moyamoya disease (MMD) is a chronic progressive cerebrovascular abnormality characterized by chronic occlusion of large intracranial vessels with smoky vascular development at the base of the skull. In patients with MMD, abnormal spontaneous brain activity would be expected.Purpose: To assess the brain activity changes in patients with MMD by resting-state functional MRI (rs-fMRI), using the percent amplitude of fluctuation (PerAF) analysis method.Materials and Methods: A total of 17 patients with MMD (3 males and 14 females) and 17 healthy control (HC) subjects with matched gender and age were recruited for this study. We used rs-fMRI to scan all the patients with MMD. Spontaneous neural activity was evaluated using the PerAF approach. The receiver operating characteristic (ROC) curve analysis was used to assess the ability of the PerAF to distinguish patients with MMD from HCs. The Hospital Anxiety and Depression Scale (HADS) tests were performed to assess the emotional status of patients with MMD and retinal nerve fiber layer thickness (RNFLT) was measured using high-resolution optical coherence tomography (hr-OCT). The relationship between the HADS scores, RNFLT values, and the PerAF signals was assessed using the Pearson's correlation analysis.Results: Compared with HCs, the PerAF signals in patients with MMD were decreased in the Frontal_Sup_Medial_R and Precentral_L, whereas those in the Caudate_L were increased. The areas under the ROC curves indicated that signals in these brain regions could distinguish between patients with MMD and HCs. The PerAF value of Frontal_Sup_Medial_R was positively correlated with the left and right eye RNFLT values and negatively correlated with the HADS scores.Conclusion: In patients with MMD, reduced PerAF signals in the Frontal_Sup_Medial_R, Precentral_L, and Caudate_L may be associated with psychiatric diseases including anxiety and depression and decreased RNFLT may be associated with ophthalmic complications due to the compression of terminal branches of the internal carotid artery in the retinal fiber layer. The PerAF can be used as an effective indicator of ocular complications of MMD and to study the neural mechanism underpinning emotional complications in patients with MMD.

Systematic CT perfusion acquisition in acute stroke increases vascular occlusion detection and thrombectomy rates

BackgroundIn patients with stroke, current guidelines recommend non-invasive vascular imaging to identify intracranial vessel occlusions (VO) that may benefit from endovascular treatment (EVT). However, VO can be missed in CT...

The Tigertriever 13 for mechanical thrombectomy in distal and medium intracranial vessel occlusions.

To report our two-center initial experience using the Tigertriever 13 in the treatment of acute stroke of distal, medium vessel occlusions (DMVO). We performed a retrospective analysis of all patients treated by mechanical thrombectomy using the Tigertriever 13 device (a manually expandable low profile stent retriever) due to an acute DMVO. Locations included the anterior, middle, and posterior cerebral artery in the A2 and A3, the M3 and M4, and the P2 or P3 segment and the superior cerebellar artery. Forty-three patients with 45 DMVOs underwent MTE using the Tigertriever 13 with the intention-to-treat approach between May 2019 and December 2020. After a median of two thrombectomy maneuvers, the successful recanalization rate (mTICI 2b-3) was 84.4% (38/45) with a first pass effect of 26.7% (12/45). The rate of symptomatic intracranial hemorrhages (sICH) and subarachnoid hemorrhages (SAH) was 7.0% (3/43) and 14.0% (6/43), respectively. At discharge, 53.5% (23/43) of the patients had a favorable clinical outcome (mRS 0-2). Mechanical thrombectomy in DMVOs using the Tigertriever 13 leads to high recanalization rates. The incidence of mostly asymptomatic hemorrhagic events appears higher compared to MTE procedures in LVOs. Further studies will help to identify anatomic and clinical criteria to define a guideline for MTE in DMVOs.

Reasons for Not Performing Mechanical Thrombectomy: A Population-Based Study of Stroke Codes.

Mechanical thrombectomy (MT) is effective for acute ischemic stroke (AIS) in selected patients with large intracranial vessel occlusion. A minority of patients with AIS receive MT. We aimed to describe the reasons for excluding patients with AIS for MT. We evaluated patients with AIS in a prospective population-based multicenter registry (Codi Ictus Catalunya registry) that includes all stroke code activations from January to June 2018 in Catalonia, Spain. We analyzed the major reasons for not treating with MT. Stroke code was activated in 3060 patients. Excluding 355 intracranial hemorrhages and 502 stroke mimics, resulted in 2203 patients with AIS (mean age 72.8±13.8 years; 44.6% were women). Of the patients with AIS, 405 (18.4%) were treated with MT. We analyzed the reasons for not treating with MT. The following reasons were considered not modifiable: absence of large intracranial vessel occlusion (922, 41.9%), transient ischemic attack (206, 9.4%), and more than one cause (124, 5.6%). The potentially modifiable reasons for not performing MT by changing selection criteria were as follows: an intracranial artery occlusion that was considered inaccessible or not indicated (48, 2.2%); clinical presentation that was considered too mild to be treated (222, 10.1%); neuroimaging criteria (129, 5.9%), age/prior modified Rankin Scale score/medical comorbidities (129, 5.9%), and therapeutic time window >8 hours (16, 0.7%). In our area, considering all potentially modifiable causes for not performing MT, the percentage of patients with AIS eligible for MT could increase from 18.4% to a maximum of 43.1%. The clinical benefit of this increase is still uncertain and should be confirmed in future trials. Criteria for stroke code activation must be considered for the generalizability of these results.

Safety and Outcome of Intravenous Recombinant Tissue Plasminogen Activator (rt-PA) in the Nursing Home Residents Following an Acute Ischemic Stroke

Background and Purpose: Intravenous recombinant tissue plasminogen activator (IV rt-PA) is an effective treatment of acute ischemic stroke. The safety and efficacy of IV rt-PA were extensively studied in adults, including both octogenarians and nonagenarians.This study provides safety outcome of exclusive nursing home (NH) residents (dependent on activities of daily living [ADLs]) , who received IV rt-PA. Not much literature or studies are available exclusively on the NH residents. Aim: To assess the safety and outcome of IV rt-PA in patients from NHs who were admitted to our university-based tertiary care hospital, using data from a prospective stroke registry. Methods: Our study is a retrospective review of patients living in nursing facilities, admitted to our neuroscience intensive care unit after receiving IV rt-PA, from January 2010 to June 2018. We reviewed the clinical symptoms, comorbid conditions, medications, diagnostic evaluation, complications, and functional outcomes. The functional outcome was assessed based on the modified Rankin Scale (mRS) at the time of discharge, and 1- and 3-month follow-up. Results: Twenty-eight NH residents (20 [71.4%] were female with a mean age of 80.96 +/− 12.43 years) were identified who had received IV rt-PA for symptoms of acute ischemic stroke. The median mRS on admission was 3, and all of them were dependent on ADL. Twenty-seven (96.5%) patients were treated within the window (≤3 h) for IV rt-PA. There were no IV rt-PA-related violations from both our hospital and outside hospital treatment protocols. The initial computed tomographic (CT) scan of 8 (28.5%) patients revealed evidence of infarction. CT angiogram of head and neck revealed an acute intracranial blood vessel occlusion in 13 (46.4%) patients, and asymptomatic stenosis of intracranial and extracranial blood vessels in 4 (14.2%) patients. Mechanical thrombectomy was attempted in 6 (21.4%) patients and among them, the procedure was unsuccessful in 2 (7.1%) patients due to severe stenosis. One (1/21; 16.6%) patient received an intra-arterial rt-PA, and 5 (5/6;83.3%) patients developed symptomatic intracranial hemorrhage within 24 h following the procedure. Families of 9/28 (32.1%) patients decided to withdraw care. The median mRS on 30 and 90 days follow-up was 4 (interquartile range: 3-6). Conclusion: In this population, mechanical thrombectomy has a high risk for hemorrhagic conversion. IV rt-PA treatment in the NH residents may not improve the outcome of ischemic stroke.

Coronavirus Disease 2019 and Stroke

An association between coronavirus disease 2019 (COVID-19) and stroke has been suggested in multiple reports. When compared with historic controls admitted for influenza, COVID-19 patients had a higher incidence of stroke than patients with historic influenza. Others have observed an increased severity of stroke and higher mortality in patients with a coincident diagnosis of COVID-19. Higher stroke severity has been related to a greater propensity toward large intracranial vessel occlusion in affected patients. The increased likelihood of large vessel disease causing stroke has been associated with the thrombogenic nature of COVID-19. Endothelial injury and inflammation have also been reported as factors contributing to stroke in COVID-19 patients.

Endovascular Thrombectomy for Large Vessel Occlusions in Covid-19 Patients

INTRODUCTIONCovid 19 infections has been shown to be associated with a range of thromboembolic disease that has implications for the neuro-endovascular management of large vessel occlusions.METHODSFive consecutive Covid-19 positive patients presented with large vessel occlusions to our institution. Covid-19 testing was performed using nasal swab. All thrombectomy cases was performed under general endotracheal anesthesia using a stent-aspiration combination as primary thrombectomy technique. The technical details of each case and the angiographic outcome are described. Routine labs including D-dimer, platelet count, coagulation panel (aPTT, INR), Interleukin 6 (IL-6), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) were evaluated in all patients. Rotational thrombelastography (ROTEM) was performed on the patients' blood samples to assess real-time clot formation/dissolution properties.RESULTSFour patients had anterior circulation large vessel occlusions and one patient had both anterior and posterior circulation occlusions. Mean age was 52.8 years and 80% were males. TICI 3 revascularization was achieved in one patient, TICI 2B achieved in two patients andTICI 2A in two patients. In our cohort, patients were on average 52.8 years old and presented with a median NIHSS of 27. All our patients had very proximal occlusions. Three patients presented with intra-cranial ICA occlusions. Two patients presented with a tandem carotid bulb thrombus in conjunction with an intracranial vessel occlusion. One patient had an ICA terminus occlusion with a concomitant basilar occlusion. Second, the intravascular clots in all our patients were prone to fragment and migrate into both new vascular territories and into distal downstream vasculature. Distal emboli into a different territory (anterior cerebral artery occlusion) was seen in two two of our five patients (40%) and distal emboli into a downstream territory was seen in all five patients (100%). An average of 2.7 pstent-retriever passes was needed to achieve a final TICI revascularization of IIb or better.CONCLUSIONCovid-19 patients are predisposed to a hypercoagulable state. When presenting with large vessel occlusions, these patients present unique challenges that make successful revascularization difficult.

Mechanical Thrombectomy in Medium Vessel Occlusions

Mechanical thrombectomy techniques for intracranial medium vessel occlusions (MeVOs) have evolved in recent years, although the optimal approach is still unclear. The aim of this study was to investigate the effectiveness and safety of mechanical thrombectomy in MeVOs using mini (0.017 inches microcatheter compatible) stent retrievers combined with low-profile (0.035 inches distal inner diameter) distal aspiration catheters through the blind exchange/mini-pinning (BEMP) technique compared with mini stent retrievers alone. Retrospective review of a prospectively maintained database of patients treated with the BEMP technique or mini stent retriever alone for intracranial MeVOs from 2017 to 2020 in a comprehensive stroke center. Both groups were compared about baseline characteristics, occlusion site, clinical presentation, clot cause, procedural outcomes (MeVO first-pass and final expanded Thrombolysis in Cerebral Ischemia score, the mini stent retriever used, number of passes with the front-line approach, and need of rescue therapy), safety outcomes (emboli to unwanted territories and hemorrhagic complications), and clinical outcomes at 90 days. Multivariable logistic regression analysis was performed with potential predictors of vessel recanalization to find independent variables associated with MeVO first-pass expanded Thrombolysis in Cerebral Ischemia 2c/3 recanalization. We reviewed 102 patients/106 MeVOs treated with the BEMP technique (n=56) or mini stent retriever (n=50). There was a higher rate of MeVO first-pass expanded Thrombolysis in Cerebral Ischemia 2c/3 recanalization (57% versus 34%, P=0.017), lower need of rescue therapy (7.1% versus 22%, P=0.028), and lower rate of emboli to new territory (1.8% versus 12%, P=0.035) and symptomatic intracranial hemorrhage (1.9% versus 12.8%, P=0.038) with the BEMP technique. After multivariable analysis, the sole independent factor associated to MeVO first-pass expanded Thrombolysis in Cerebral Ischemia 2c/3 recanalization was the BEMP technique (odds ratio, 2.72 [95% CI, 1.19-6.22]; P=0.018). In the setting of MeVOs, the BEMP technique may lead to higher rates of the first-pass recanalization and a lower incidence of symptomatic intracranial hemorrhage than mini stent retrievers alone.

Open Microvascular Thrombectomy for Acute Intracranial Large Vessel Occlusion: Microsurgery in the Endovascular Thrombectomy Era

Open microsurgical thrombectomy for acute intracranial large vessel occlusion (LVO) has been the subject of dozens of case reports and series. However, no clear indications exist to define its role in the management of acute ischemic stroke. Our aim was to review all the available data on open microsurgical thrombectomy, for both spontaneous as well as iatrogenic intracranial vessel occlusion, in terms of indication and results. Of the 390 articles screened, 33 were included after full text screening. A total of 232 patients were reported, of whom 208 received microsurgical thrombectomy and 24 received bypass for large vessel occlusion. Patients were divided into a historic cohort (before 2002) and a recent cohort (articles published after 2002). Patients from the historic cohort were younger: median age, 55 years (interquartile range, 34-57 years) versus 69 years (interquartile range, 63-75 years) in the recent cohort (P < 0.01). The procedure was successful more often in the recent cohort (65% of patients in the historic cohort vs. 98% of patients in the recent cohort) and more patients experienced neurologic improvement (56% of patients in the historic cohort vs. 69% in the recent cohort). In the era of endovascular thrombectomy, open microsurgical techniques might still play a role in highly selected patients. The reported patients show that microsurgical thrombectomy seems efficient and effective in improving patient outcome. Ideally, a multidisciplinary approach with vascular neurosurgeons trained and skilled in microvascular techniques is recommended.

May endovascular thrombectomy without CT perfusion improve clinical outcome?

BackgroundDAWN and DEFUSE-3 trials demonstrated the benefit of endovascular thrombectomy in late-presenting acute ischemic strokes due to anterior circulation large vessel occlusion. The aim of our study is to evaluate results of endovascular thrombectomy in large intracranial vessel occlusion without perfusion CT patient selection. Methodswe reviewed our prospectively collected endovascular databases for patients with an acute stroke from March 2016 to October 2018, treated after 6 h from stroke onset, without perfusion CT selection. Baseline characteristics, procedural data, and outcomes were evaluated. A good outcome was defined as a 90-day modified Rankin Scale score of 0–2. The association between clinical and procedural parameters and functional outcome was assessed. Resultsout of 212 patients 55 were treated after 6 h from stroke onset, 49 of which for an anterior circulation occlusion. 18/49 were functional independent at 90 days (mRS 0–2), Successful recanalization (mTICI 2b to 3) was achieved in 38/49 patients (77 %). Multivariate logistic regression indicated that a low baseline NIHSS was associated with favorable outcome (OR 0.66, 95 % CI 0.52−0.83, p-value 0.001). Conclusionsin our retrospective analysis, baseline NIHSS is the only parameter that can predict good outcome (90-days mRS 0–2). We confirm data from recent papers assessing that perfusion CT can provide a better patients' selection compared to mCTA for large vessels occlusion treated beyond six hours from symptom onset.

Carotid artery webs in embolic stroke of undetermined source with large intracranial vessel occlusion.

Whether carotid artery web can be considered as a potential source of arterial thromboembolism in ischemic stroke remains uncertain. In a large sample of individuals with large intracranial artery occlusion, we compared the prevalence of carotid artery webs between patients with and without embolic stroke of undetermined source. In a single-center study of consecutive patients with anterior circulation ischemic stroke referred for mechanical thrombectomy, the presence of carotid artery web was systematically assessed by two independent readers. Thereafter, its prevalence was compared between patients with and without embolic stroke of undetermined source. Among 466 patients of whom 12% were considered to have had an embolic stroke of undetermined source, ipsilateral carotid artery web was detected in 1.9% (confidence interval 95% = 0.7-3.1). Ipsilateral carotid artery web was more frequent in embolic stroke of undetermined source than in the rest of the sample (10.7% (confidence interval 95% = 2.7-18.7] vs. 0.7% (0-1.5), P < 0.001). This difference remains significant after adjustment for sex, age, and vascular risk factor (odds ratio: 12.5 (2.1-72), P = 0.005) or after exclusion of patients with any other bulb wall thickening (P = 0.025). In contrast, the difference of prevalence of contralateral carotid artery web between the two groups did not reach statistical significance (2.4% vs. 1.9%, P = 0.6). Our results suggest that the presence of a carotid artery web might be considered as a potential source of large intracranial artery embolism. Longitudinal studies are needed to assess the exact risk of recurrence associated with these lesions.

Transcranial Doppler sonography for detecting stenosis or occlusion of intracranial arteries in people with acute ischaemic stroke

An occlusion or stenosis of intracranial large arteries can be detected in the acute phase of ischaemic stroke in about 42% of patients. The approved therapies for acute ischaemic stroke are thrombolysis with intravenous recombinant tissue plasminogen activator (rt-PA), and mechanical thrombectomy; both aim to recanalise an occluded intracranial artery. The reference standard for the diagnosis of intracranial stenosis and occlusion is intra-arterial angiography (IA) and, recently, computed tomography angiography (CTA) and magnetic resonance angiography (MRA), or contrast-enhanced MRA. Transcranial Doppler (TCD) and transcranial colour Doppler (TCCD) are useful, rapid, noninvasive tools for the assessment of intracranial large arteries pathology. Due to the current lack of consensus regarding the use of TCD and TCCD in clinical practice, we systematically reviewed the literature for studies assessing the diagnostic accuracy of these techniques compared with intra-arterial IA, CTA, and MRA for the detection of intracranial stenosis and occlusion in people presenting with symptoms of ischaemic stroke. To assess the diagnostic accuracy of TCD and TCCD for detecting stenosis and occlusion of intracranial large arteries in people with acute ischaemic stroke. We limited our searches from January 1982 onwards as the transcranial Doppler technique was only introduced into clinical practice in the 1980s. We searched MEDLINE (Ovid) (from 1982 to 2018); Embase (Ovid) (from 1982 to 2018); Database of Abstracts of Reviews of Effects (DARE); and Health Technology Assessment Database (HTA) (from 1982 to 2018). Moreover, we perused the reference lists of all retrieved articles and of previously published relevant review articles, handsearched relevant conference proceedings, searched relevant websites, and contacted experts in the field. We included all studies comparing TCD or TCCD (index tests) with IA, CTA, MRA, or contrast-enhanced MRA (reference standards) in people with acute ischaemic stroke, where all participants underwent both the index test and the reference standard within 24 hours of symptom onset. We included prospective cohort studies and randomised studies of test comparisons. We also considered retrospective studies eligible for inclusion where the original population sample was recruited prospectively but the results were analysed retrospectively. At least two review authors independently screened the titles and abstracts identified by the search strategies, applied the inclusion criteria, extracted data, assessed methodological quality (using QUADAS-2), and investigated heterogeneity. We contacted study authors for missing data. A comprehensive search of major relevant electronic databases (MEDLINE and Embase) from 1982 to 13 March 2018 yielded 13,534 articles, of which nine were deemed eligible for inclusion. The studies included a total of 493 participants. The mean age of included participants was 64.2 years (range 55.8 to 69.9 years). The proportion of men and women was similar across studies. Six studies recruited participants in Europe, one in south America, one in China, and one in Egypt. Risk of bias was high for participant selection but low for flow, timing, index and reference standard. The summary sensitivity and specificity estimates for TCD and TCCD were 95% (95% CI = 0.83 to 0.99) and 95% (95% CI = 0.90 to 0.98), respectively. Considering a prevalence of stenosis or occlusion of 42% (as reported in the literature), for every 1000 people who receive a TCD or TCCD test, stenosis or occlusion will be missed in 21 people (95% CI = 4 to 71) and 29 (95% CI = 12 to 58) will be wrongly diagnosed as harbouring an intracranial occlusion. However, there was substantial heterogeneity between studies, which was no longer evident when only occlusion of the MCA was considered, or when the analysis was limited to participants investigated within six hours. The performance of either TCD or TCCD in ruling in and ruling out a MCA occlusion was good. Limitations of this review were the small number of identified studies and the lack of data on the use of ultrasound contrast medium. This review provides evidence that TCD or TCCD, administered by professionals with adequate experience and skills, can provide useful diagnostic information for detecting stenosis or occlusion of intracranial vessels in people with acute ischaemic stroke, or guide the request for more invasive vascular neuroimaging, especially where CT or MR-based vascular imaging are not immediately available. More studies are needed to confirm or refute the results of this review in a larger sample of stroke patients, to verify the role of contrast medium and to evaluate the clinical advantage of the use of ultrasound.

Endovascular Thrombectomy of Calcified Emboli in Acute Ischemic Stroke: A Multicenter Study.

Large intracranial vessel occlusion due to calcified emboli is a rare cause of major stroke. We assessed the prevalence, imaging appearance, the effectiveness of mechanical thrombectomy, and clinical outcome of patients with large-vessel occlusion due to calcified emboli. We performed a retrospective analysis of clinical and procedural data of consecutive patients who underwent mechanical thrombectomy due to calcified emboli in 7 European stroke centers. We screened 2969 patients, and 40 patients matched the inclusion criteria, accounting for a prevalence of 1.3%. The mean maximal density of the thrombus was 327 HU (range, 150-1200 HU), and the mean thrombus length was 9.2 mm (range, 4-20 mm). Four patients had multiple calcified emboli, and 2 patients had an embolic event during an endovascular intervention. A modified TICI score of ≥2b was achieved in 57.5% (23/40), with minimal-to-no reperfusion (modified TICI 0-1) in 32.5% (13/40) and incomplete reperfusion (modified TICI 2a) in 10% (4/40). Excellent outcome (mRS 0-1) was achieved in only 20.6%, functional independence (mRS 0-2) in 26.5% and 90-day mortality was 55.9%. Acute ischemic stroke with large-vessel occlusion due to calcified emboli is a rare entity in patients undergoing thrombectomy, with considerably worse angiographic outcome and a higher mortality compared with patients with noncalcified thrombi. Good functional recovery at 3 months can still be achieved in about a quarter of patients.

Abstract WMP16: Radiographic Characteristics of Mild Ischemic Stroke Patients With Visible Intracranial Occlusion; Data From the INTERRSeCT Multi-Center Prospective Imaging Study

Background: Early neurological deterioration occurs in one third of mild ischemic strokes primarily due to the presence of a visible intracranial vessel occlusion. We studied the clinical and vascular occlusive patterns, thrombus characteristics and recanalization rates in patients with mild ischemic stroke and a visible intracranial vessel occlusion. Methods: We studied patients enrolled in the INTERRSeCT multi-center prospective study of acute ischemic strokes with visible intracranial occlusions. We compared the clinical, thrombus characteristics and recanalization rates between two groups, 1) mild ischemic NIHSS≤5 and 2) moderate/severe strokes NIHSS &gt;5, with or without IV alteplase treatment. Vessel imaging with CT angiography (CTA) was initiated within 12 hrs of symptom onset followed by repeat imaging with CTA or cerebral angiogram (before endovascular therapy; EVT) within 4 +/- 2 hrs. Results: Among 575 patients with a visible intracranial occlusion, 12.9% had mild strokes with similar patient characteristics compared to the moderate/severe stroke group. Residual flow grades were similar between the two groups (residual flow grades I-II, 21% vs 19%). The mild stroke group had longer symptom-onset-to -CT (240 vs 167 min, p=0.02) and -CTA (246 vs 172 min, p=0.02) times, longer CT to needle time (35 vs 26 min, p&lt;0.01), more distal occlusions (49% in M2 of the middle cerebral artery), lower clot burden scores 9 (6-9) vs 6 (4-9) (p&lt;0.001), better collateral flow (9.1 vs 7.6, p=0.001) and no association between residual flow grade and recanalization. The mild stroke group was less likely to receive IV alteplase (62% vs 84%), but more likely to recanalize (rAOL2b and 3) with (46% vs 29%) and without (38% vs 26%) IV alteplase. Conclusion: Some thrombus characteristics that predict recanalization in more severe strokes do not predict recanalization in mild strokes, such as residual blood flow through intracranial occlusions, though they have similar cardiovascular risk factors. Less than half of patients with mild strokes recanalized with IV alteplase which was associated with longer decision-making times suggesting that more aggressive use of thrombolytics and/or EVT may be viable treatment options in this population.

Abstract WP76: Artificial Intelligence CTA Vessel Density Mapping to Enhance Identification of Large Vessel Occlusions in Mobile Stroke Unit

Background: Equipped with CT scanners capable of imaging the brain parenchyma and vasculature, Mobile Stroke Units (MSU) have the ability to image, diagnose and treat stroke patients in the prehospital setting. Automated CTA vessel density mapping could enhance frontline neurologist scan review in identifying large vessel occlusion (LVO), ensuring appropriate patient diagnosis and routing. Methods: We analyzed consecutive acute ischemic stroke patients undergoing CTA imaging in a regional Mobile Stroke Unit. Automated CTA vessel density mapping was performed in the field immediately after scan completion. CTA source images were wirelessly transferred to an off-site processing server (RAPID.Ai, IschemiaView) for artery reconstruction and color-coded density mapping, with blue, green, yellow, and red color shading indicating vessel density decreases of 70%-85%, 60%-75%, 45%-60%, and &lt;45%. Results: Among all 16 patients, median processing time was 186 secs, and all images were available in time to aid clinical decision-making. Overall, automated processing yielded evaluable images in 94% (suboptimal contrast opacification precluded analysis of 1). Of the 15 diagnostically adequate exams, 100% (15/15) showed concordance for identification of anterior circulation occluded/abnormal vessel territories between automated CTA vessel density mapping and expert physician final CTA interpretation. Cases included true positives in 7, and true negatives in 8. Among true positives, CTA vessel density mapping identified the symptomatic occlusion in 6/6 and also correctly identified a severe cervical ICA stenosis unrelated to the clinical presentation in 1/1. Correctly detected intracranial occlusions included: ICA-17%. M1-17%, M1-M2 junction-17%, and M2-50%. Degree of vessel density diminution correlated with proximal-distal occlusion location. Conclusion: CTA vessel density mapping can feasibly and efficiently be conducted in Mobile Stroke Units and shows high accuracy in detection of large and medium intracranial vessel occlusions. Extension of mapping to the intracranial posterior circulation and algorithmic adjustment for proximal cervical stenoses/occlusions would further improve utility in aiding prehospital routing.

Recanalization of Emergent Large Intracranial Vessel Occlusion through Intravenous Thrombolysis: Frequency, Clinical Outcome, and Reperfusion Pattern

Background: According to a recent meta-analysis, 1 out of 10 patients with emergent large intracranial vessel occlusion (ELVO) causing stroke have recanalization after intravenous thrombolysis (IVT) alone. However, rate, clinical outcome, and recanalization pattern of this phenomenon are poorly understood. Objectives and Methods: Patients with ELVO recanalized only by IVT were analyzed, and frequency of recanalization, clinical outcome, safety variables, and reperfusion pattern were assessed. These patients were compared to a group of patients with ELVO who underwent endovascular thrombectomy with or without prior IVT. Results: Successful or sufficient recanalization after IVT alone occurred in 81 of 760 patients (10.6%) with ELVO who had been referred for endovascular thrombectomy. These 81 patients (group 1) were compared to a group of patients receiving endovascular thrombectomy with prior IVT (group 2) or without (group 3). A good clinical outcome at 90 days was seen in 61.7% of patients in group 1, 32.2% in group 2, and 34.5% in group 3 (p < 0.001). The 3 groups had no significant differences in intracranial hemorrhage. IVT was not independently associated with symptomatic intracranial hemorrhage, parenchymal hematoma, or subarachnoid hemorrhage. Mortality at 90 days was 9.9% in group 1, 20.7% in group 2, and 29.6% in group 3 (p < 0.001). After adjusting for all relevant variables, outcome and mortality differences were nonsignificant. No difference in the rate of successful reperfusion (modified treatment in cerebral ischemia [mTICI] 2b/3) was found. A reperfusion mTICI 3 was achieved in 18.5% in group 1, 60.7% in group 2, and 57.1% in group 3 (p < 0.001). Patients in group 1 had lower chance of achieving a complete recanalization (mTICI 3) compared to patients in group 2, OR 0.15 (95% CI 0.08–0.29) and in group 3, OR 0.17 (95% CI 0.09–0.32; p < 0.001). Conclusions: Primary IVT in ELVO caused a recanalization rate of 10.6%, making endovascular treatment either unnecessary or impossible. Early recanalization of ELVO with only IVT is associated with a 61.7% independence rate at 90 days and similar successful reperfusion rates (mTICI2b/3) compared to ELVO treated with endovascular treatment, with or without previous IVT. However, recanalization only through IVT achieves a lower rate of mTICI 3 reperfusion when compared to endovascular treatment.

“Adaptative endovascular strategy to the CloT MRI in large intracranial vessel occlusion” (VECTOR): Study protocol of a randomized control trial

A correlation between the susceptibility vessel sign (SVS) and red thrombi has been identified in MRI. We hypothesized that the Embotrap allow better retrieving of SVS+ thrombi. The AdaptatiVe Endovascular strategy to the CloT MRI in large intracranial vessel Occlusion (VECTOR) trial is a multicenter, prospective and randomized study designed to compare a first-line strategy combining Embotrap added to contact aspiration (CA) versus CA alone in patients with SVS+ occlusions.