Thrombectomy for Distal, Medium Vessel Occlusions: A Consensus Statement on Present Knowledge and Promising Directions

Complete recanalization predicts favorable outcome in patients with distal M2-M3 middle cerebral artery occlusions following endovascular thrombectomy

BACKGROUND

- scanty articles illustrate the prognostic factors for favorable outcome after endovascular thrombectomy (EVT) in distal vessel occlusion (DMVO). Moreover, the current literature is diversified; conglomerating both primary, secondary, and anterior, posterior circulations embolic strokes in the same shell.

PURPOSE

to identify the association between complete reperfusion and favorable outcome following EVT for DMVO in the middle cerebral artery (MCA) territory.

METHODS

-we performed a retrospective analysis of prospectively maintained EVT registries at two comprehensive stroke centers between January 2015 and December 2019 for consecutive stroke patients with MCA-DMVO. DMVO was defined as an occlusion of distal M2 and M3 segments of the MCA. Only patients with primary isolated occlusions were included. A multivariate logistic regression was utilized to identify clinical and procedural-related factors associated with the 90-day favorable clinical outcome [defined as modified Rankin score (mRS) 0-2] after EVT.

RESULTS

-Out of 1823 within the registries; 66 patients (median age was 72 (60-78) and 59% were males) with primary isolated DMVO of the MCA were eligible for inclusion in the current study. Complete reperfusion was achieved in 56% (37/66) of the patients with no difference among the reperfusion strategies while the favorable outcome was observed in 68% (45/66). In the multivariate analysis, final complete reperfusion [modified Thrombolysis In Cerebral Infarction (mTICI) score 2c-3] was significantly associated with favorable outcome [aOR=7.69; (95% CI 1.73-34.17); p=.01], while higher baseline NIHSS score [aOR=0.82; (95% CI 0.69-0.98); p=.03] and increased imaging to puncture interval [aOR=0.99; (95% CI 0.98, 1.00); p=.01] decreased the probability of the favorable outcome.

CONCLUSION

according to our results, complete reperfusion was the most significant predictor of the favorable outcome, while higher baseline NIHSS and longer imaging to puncture interval decreased the probability of the favorable outcome.

Initial Experience Using the New pHLO 0.072-inch Large-Bore Catheter for Direct Aspiration Thrombectomy in Acute Ischemic Stroke

PURPOSE

A direct aspiration, first pass technique (ADAPT) has been introduced as a rapid and safe thrombectomy strategy in patients with intracranial large vessel occlusion (LVO). The aim of the study is to determine the technical feasibility, safety, and functional outcome of ADAPT using the newly released large bore pHLO 0.072-inch aspiration catheter (AC; Phenox).

MATERIALS AND METHODS

We performed a retrospective analysis of data collected prospectively (October 2019-November 2021) from 2 comprehensive stroke centers. Accessibility of the thrombus, vascular recanalization, time to recanalization, and procedure-related complications were evaluated. National Institutes of Health stroke scale scores at presentation and discharge and the modified Rankin scale (mRS) score at 90 days post-procedure were recorded.

RESULTS

Twenty-five patients (14 female, 11 male) with occlusions of the anterior circulation were treated. In 84% of cases, ADAPT led to successful recanalization with a median procedure time of 28 minutes. In the remaining cases, successful recanalization required (to a total of 96%; modified thrombolysis in cerebral infarction score 2b/3) the use of stent retrievers. No AC-related complications were reported. Other complications included distal migration of the thrombus, requiring a stent-retriever, and symptomatic PH2 hemorrhage in 16% and 4%, respectively. After 3 months, 52% of the patients had mRS scores of 0-2 with an overall mortality rate of 20%.

CONCLUSION

Results from our retrospective case series revealed that thrombectomy of LVOs with pHLO AC is safe and effective in cases of large-vessel ischemic stroke. Rates of complete or near-complete recanalization after the first pass with this method might be used as a new benchmark in future trials.

Recommendations on the use of computed tomography in the stroke code: Consensus document SENR, SERAU, GEECV-SEN, SERAM

The Spanish Society of Emergency Radiology (SERAU), the Spanish Society of Neuroradiology (SENR), the Spanish Society of Neurology through its Cerebrovascular Diseases Study Group (GEECV-SEN) and the Spanish Society of Medical Radiology (SERAM) have met to draft this consensus document that will review the use of computed tomography in the stroke code patients, focusing on its indications, the technique for its correct acquisition and the possible interpretation mistakes.

Desired Qualities of Endovascular Tools and Barriers to Treating Medium Vessel Occlusion MeVO : Insights from the MeVO-FRONTIERS International Survey

BACKGROUND

Endovascular treatment (EVT) for stroke due to medium vessel occlusion (MeVO) can be technically challenging and specific endovascular tools are needed to safely and effectively recanalize these relatively small and fragile vessels. We aimed to gain insight into availability and desired qualities of endovascular devices used in MeVO stroke and examined barriers to adoption of MeVO EVT in clinical practice on a global scale.

METHODS

We conducted a case-based international survey among neurointerventionalists. As a part of the survey, participants were asked whether they felt appropriate endovascular tools for MeVO stroke exist and are available to them in their clinical practice. We then examined barriers to adopting MeVO EVT and analyzed them by geographic regions.

RESULTS

A total of 263 neurointerventionists participated, of which 178 (67.7%) and 83 (31.6%) provided responses on desired qualities of MeVO EVT tools and on barriers to their adoption in local practice, respectively. The majority 121/178 (68%) felt there was substantial room for improvement regarding existing tools. A large proportion 131/178 (73.6%) felt they had appropriate access to existing tools. The most commonly mentioned barrier for adopting MeVO EVT in North America was "awaiting better tools" (9/28 responses, 32.1%), while "awaiting better evidence" (8/26 responses, 30.8%), and the need for improved "funding" (7/26 responses, 26.9%) were important barriers in Europe.

CONCLUSION

The majority of surveyed neurointerventionalists felt that dedicated MeVO EVT tools can be substantially improved upon. Different regions face various challenges in adoption of MeVO EVT, but overall, physicians are mostly awaiting better MeVO EVT tools.

Reperfusion Treatments in Disabling Versus Nondisabling Mild Stroke due to Anterior Circulation Vessel Occlusion

BACKGROUND

The benefit of distinguishing between disabling versus nondisabling deficit in mild acute ischemic stroke due to endovascular thrombectomy-targetable vessel occlusion (EVT-tVO; including anterior circulation large and medium-vessel occlusion) is unknown. We compared safety and efficacy of acute reperfusion treatments in disabling versus nondisabling mild EVT-tVO.

METHODS

From the Safe Implementation of Treatments in Stroke-International Stroke Thrombolysis Register, we included consecutive acute ischemic stroke patients (2015-2021) treated within 4.5 hours, with full NIHSS items availability and score ≤5, evidence of intracranial internal carotid artery, M1, A1-2, or M2-3 occlusion. After propensity score matching, we compared efficacy (3-month modified Rankin Scale score of 0-1, modified Rankin Scale score of 0-2, and early neurological improvement) and safety (nonhemorrhagic early neurological deterioration, any intracerebral or subarachnoid hemorrhage, symptomatic intracranial hemorrhage, and death at 3-month) outcomes in disabling versus nondisabling patients-adopting an available definition.

RESULTS

We included 1459 patients. Propensity score matched analysis of disabling versus nondisabling EVT-tVO (n=336 per group) found no significant differences in efficacy (modified Rankin Scale score 0-1: 67.4% versus 71.5%, P=0.336; modified Rankin Scale score 0-2: 77.1% versus 77.6%, P=0.895; early neurological improvement: 38.3% versus 44.4%, P=0.132) and safety (nonhemorrhagic early neurological deterioration: 8.5% versus 8.0%, P=0.830; any intracerebral hemorrhage or subarachnoid hemorrhage: 12.5% versus 13.3%, P=0.792; symptomatic intracranial hemorrhage: 2.6% versus 3.4%, P=0.598; and 3-month death: 9.8% versus 9.2%, P=0.844) outcomes.

CONCLUSIONS

We found similar safety and efficacy outcomes after acute reperfusion treatment in disabling versus nondisabling mild EVT-tVO; our findings suggest to adopt similar acute treatment approaches in the 2 groups. Randomized data are needed to clarify the best reperfusion treatment in mild EVT-tVO.

Thrombectomy versus Medical Management for Isolated Anterior Cerebral Artery Stroke: An International Multicenter Registry Study

Background Evidence supporting a potential benefit of thrombectomy for distal medium vessel occlusions (DMVOs) of the anterior cerebral artery (ACA) is, to the knowledge of the authors, unknown. Purpose To compare the clinical and safety outcomes between mechanical thrombectomy (MT) and best medical treatment (BMT) with or without intravenous thrombolysis for primary isolated ACA DMVOs. Materials and Methods Treatment for Primary Medium Vessel Occlusion Stroke, or TOPMOST, is an international, retrospective, multicenter, observational registry of patients treated for DMVO in daily practice. Patients treated with thrombectomy or BMT alone for primary ACA DMVO distal to the A1 segment between January 2013 and October 2021 were analyzed and compared by one-to-one propensity score matching (PSM). Early outcome was measured by the median improvement of National Institutes of Health Stroke Scale (NIHSS) scores at 24 hours. Favorable functional outcome was defined as modified Rankin scale scores of 0-2 at 90 days. Safety was assessed by the occurrence of symptomatic intracerebral hemorrhage and mortality. Results Of 154 patients (median age, 77 years; quartile 1 [Q1] to quartile 3 [Q3], 66-84 years; 80 men; 94 patients with MT; 60 patients with BMT) who met the inclusion criteria, 110 patients (median age, 76 years; Q1-Q3, 67-83 years; 50 men; 55 patients with MT; 55 patients with BMT) were matched. DMVOs were in A2 (82 patients; 53%), A3 (69 patients; 45%), and A3 (three patients; 2%). After PSM, the median 24-hour NIHSS point decrease was -2 (Q1-Q3, -4 to 0) in the thrombectomy and -1 (Q1-Q3, -4 to 1.25) in the BMT cohort (P = .52). Favorable functional outcome (MT vs BMT, 18 of 37 [49%] vs 19 of 39 [49%], respectively; P = .99) and mortality (MT vs BMT, eight of 37 [22%] vs 12 of 39 [31%], respectively; P = .36) were similar in both groups. Symptomatic intracranial hemorrhage occurred in three (2%) of 154 patients. Conclusion Thrombectomy appears to be a safe and technically feasible treatment option for primary isolated anterior cerebral artery occlusions in the A2 and A3 segment with clinical outcomes similar to best medical treatment with and without intravenous thrombolysis. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Zhu and Wang in this issue.

Acute isolated posterior cerebral artery stroke treated with mechanical thrombectomy: A single-center experience and review of the literature

BACKGROUND

Acute isolated posterior cerebral artery (PCA) occlusions account for 5-10% of all ischemic events. Due to peculiar patient presentation, the potential benefit of mechanical thrombectomy (MT) remains controversial. We evaluated the safety, feasibility, and effectiveness of MT in our patients and compared our results with the literature review conducted.

METHODS

Charts were reviewed retrospectively for consecutive patients diagnosed with acute PCA stroke who underwent MT. Demographics, procedural, and follow-up details were noted. For the literature review, a systematic search of PubMed, MEDLINE, and EMBASE databases was conducted for the keywords "posterior cerebral artery" and "thrombectomy" for articles published between January 1, 2010 and June 30, 2021. Estimated rates for recanalization, favorable outcomes (modified Rankin Scale [mRS] score 0-2), symptomatic intracerebral hemorrhage (sICH), and mortality were extracted.

RESULTS

Our cohort included 21 patients. Mean age was 71.2 years (standard deviation [SD] ± 10.2). Median National Institutes of Health Stroke Scale (NIHSS) presentation score was 9 (interquartile range [IQR] 5-15), with visual symptoms reported in 12(57.1%) patients. Overall, final modified thrombolysis in cerebral infarction (mTICI) 2b-3 was achieved in 17 patients (80.9%) with first-pass mTICI 2b-3 attained in 8 (38.1%). Postprocedure sICH occurred in 1 (4.8%) patient. Fifteen (71.4%) patients had a 0-2 mRS score at 90 days. Visual symptoms resolved in 10 of 12(83.3%) patients. Mortality occurred in 2 (9.5%) patients. For the systematic review, cohorts from 4 articles plus ours were included, totaling 222 patients. The estimated rate of successful recanalization was 85.25% (95% confidence interval[CI], 73.05%-97.45%), sICH was 3.60% (95% CI, 1.11%-6.09%), and mortality was 10.51% (95% CI, 5.88%-15.15%).

CONCLUSION

The results of our series and systematic review indicate MT as a potentially safe and effective treatment modality for acute PCA stroke. These results also indicate that patient selection and assessment may be the key in obtaining favorable outcomes.

Distal Embolization in Relation to Radiological Thrombus Characteristics, Treatment Details, and Functional Outcome

BACKGROUND

Distal embolization (DE) is a common complication of endovascular treatment (EVT). We investigated the association of radiological thrombus characteristics and treatment details with DE.

METHODS

Patients with thin-slice (≤2.5 mm) baseline noncontrast computed tomography and computed tomography angiography from the ESCAPE-NA1 trial (Efficacy and Safety of Nerinetide for the Treatment of Acute Ischemic Stroke) were included. Thrombus annotation was performed manually on coregistered scans by experienced readers. We assessed thrombus location, distance from internal carotid artery terminus, length, perviousness, absolute attenuation, and hyperdense artery sign. In addition, we evaluated balloon guide catheter use during EVT, first-line EVT approach, the number of thrombectomy passes, and prior intravenous thrombolysis administration. DE was defined as the occurrence of emboli distal to the target artery or in new territories during EVT. The association between thrombus characteristics, treatment details, and DE was evaluated using descriptive statistics and multivariable mixed-effects logistic regression, resulting in adjusted odds ratios (aOR) with 95% CI. Interaction between IVT and radiological thrombus characteristics was assessed by adding interaction terms in separate models.

RESULTS

In total, 496 out of 1105 (44.9%) ESCAPE-NA1 patients were included. DE was detected in 251 out of 496 patients (50.6%). Patients with DE had longer thrombi (median, 28.5 [interquartile range, 20.8-42.3] mm versus 24.4 [interquartile range, 17.1-32.4] mm; P<0.01). There were no statistically significant differences in the other thrombus characteristics. Factors associated with DE were thrombus length (aOR, 1.02 [95% CI, 1.01-1.04]), balloon guide catheter use (aOR, 0.49 [95% CI, 0.29-0.85]), and number of passes (aOR, 1.24 [95% CI, 1.04-1.47]). In patients with hyperdense artery sign, IVT was associated with reduced odds of DE (aOR, 0.55 [95% CI, 0.31-0.97]), P for interaction=0.04.

CONCLUSIONS

DE was associated with longer thrombi, no balloon guide catheter use, and more EVT passes. IVT was associated with a reduced risk of DE in patients with hyperdense artery sign. These findings may support treatment decisions on IVT and EVT approaches.

Comparing Tigertriever 13 to other thrombectomy devices for distal medium vessel occlusion: A systematic review and meta-analysis

BACKGROUND

There is limited evidence on the optimal endovascular strategy for treatment of distal medium-vessel occlusions (DMVO). The low-profile Tigertriever 13 stent-triever shows early promise as an adaptable device that can navigate the distal vasculature without increasing complication risk in DMVO.

METHODS

Using Nested Knowledge, we screened literature for RCTs and cohort studies on the endovascular treatment of DMVO. The primary outcome was reperfusion success, as measured by thrombolysis in cerebral infarction (TICI) ≥ 2b and secondary outcomes included rate of symptomatic intracranial hemorrhage (sICH), mortality at 90 days, and modified Rankin scale (mRS) scores 0-2 at 90 days. A random-effects model was used to compute pooled prevalence rates and their corresponding 95% confidence intervals (CI).

RESULTS

Eleven studies with 1402 patients, 167 patients treated by Tigertriever 13 and 1235 patients treated by other devices, were included in the meta-analysis. The rate of reperfusion success was similar in patients treated by Tigertriever 13 (83.2% [95% CI: 71.5-96.7%]) versus other devices (81.6% [95% CI: 75.3-88.4%], p > 0.05). The rate of sICH was also similar in patients treated by Tigertriever 13 (7.2% [95% CI: 4.1-12.5%]) versus other devices (6.9% [95% CI: 5.5-8.8%]). There was significant heterogeneity in the reporting of mortality and mRS.

CONCLUSIONS

Tigertriever 13 had similar rates of reperfusion success and sICH as other devices used for the treatment of DMVO. Heterogeneity in data element reporting prevented further analyses. Further studies evaluating Tigertriever 13 and other potential devices in DMVO should attempt to harmonize data element reporting.

The Benefit of a Complete over a Successful Reperfusion Decreases with Time

OBJECTIVE

Time from stroke onset to reperfusion (TSOR) is strongly associated with outcomes after endovascular treatment. A near-to-complete or complete reperfusion (modified Treatment in Cerebral Ischemia [mTICI] 2c-3) is associated with improved outcomes compared with a successful reperfusion (mTICI 2b). However, it is unknown whether this association remains stable as TSOR increases. Therefore, we sought to investigate the association between TSOR and outcomes according to the reperfusion status.

METHODS

We analyzed data from the Endovascular Treatment in Ischemic Stroke registry, a prospective, observational, multicentric study of acute ischemic stroke patients treated with endovascular treatment in 21 centers in France. We included patients with anterior occlusions (M1, internal carotid artery, tandem), with a known time of symptom onset. Outcomes were early neurological improvement at 24 hours and favorable outcome (modified Rankin Scale between 0 and 2) at 90 days.

RESULTS

Overall, 4,444 patients were analyzed. Compared with a mTICI 2b, a mTICI 2c-3 at 1 hour was associated with higher mean marginal probabilities of early neurological improvement (25.6%, 95% CI 11.7-39.5, p = 0.0003) and favorable outcome (15.2%, 95% CI 3.0-27.4, p = 0.0143), and progressively declined with TSOR. The benefit of a mTICI 2c-3 over a mTICI 2b was no longer significant regarding the rates of early neurological improvement and favorable outcome after a TSOR of 414 and 344 minutes, respectively.

INTERPRETATION

The prognostic value of a complete over a successful reperfusion progressively declined with time, and no difference regarding the rates of favorable outcome was observed between a complete and successful reperfusion beyond 5.7 hours. ANN NEUROL 2023.

Clinical criteria to exclude acute vascular pathology on CT angiogram in patients with dizziness

BACKGROUND

Patients presenting to the emergency department (ED) with dizziness may be imaged via CTA head and neck to detect acute vascular pathology including large vessel occlusion. We identify commonly documented clinical variables which could delineate dizzy patients with near zero risk of acute vascular abnormality on CTA.

METHODS

We performed a cross-sectional analysis of adult ED encounters with chief complaint of dizziness and CTA head and neck imaging at three EDs between 1/1/2014-12/31/2017. A decision rule was derived to exclude acute vascular pathology tested on a separate validation cohort; sensitivity analysis was performed using dizzy "stroke code" presentations.

RESULTS

Testing, validation, and sensitivity analysis cohorts were composed of 1072, 357, and 81 cases with 41, 6, and 12 instances of acute vascular pathology respectively. The decision rule had the following features: no past medical history of stroke, arterial dissection, or transient ischemic attack (including unexplained aphasia, incoordination, or ataxia); no history of coronary artery disease, diabetes, migraines, current/long-term smoker, and current/long-term anti-coagulation or anti-platelet medication use. In the derivation phase, the rule had a sensitivity of 100% (95% CI: 0.91-1.00), specificity of 59% (95% CI: 0.56-0.62), and negative predictive value of 100% (95% CI: 0.99-1.00). In the validation phase, the rule had a sensitivity of 100% (95% CI: 0.61-1.00), specificity of 53% (95% CI: 0.48-0.58), and negative predictive value of 100% (95% CI: 0.98-1.00). The rule performed similarly on dizzy stroke codes and was more sensitive/predictive than all NIHSS cut-offs. CTAs for dizziness might be avoidable in 52% (95% CI: 0.47-0.57) of cases.

CONCLUSIONS

A collection of clinical factors may be able to "exclude" acute vascular pathology in up to half of patients imaged by CTA for dizziness. These findings require further development and prospective validation, though could improve the evaluation of dizzy patients in the ED.

Tandem occlusions involving the internal carotid and anterior cerebral arteries-A rare form of stroke: Results from the multicenter EVATRISP collaboration study

Background

Patients with stroke secondary to isolated anterior cerebral artery (ACA) occlusions have poor outcomes. Whether tandem occlusions (TO) of the extracranial internal carotid (ICA) and the ACA carry even worse outcomes that remain unknown.

Methods

Patients with TO involving ICA and ACA occlusions were identified from 14 participating centers from the EndoVascular treatment And ThRombolysis in Ischemic Stroke Patients (EVATRISP) project which is a multicenter, observational, cohort study with prospective accrual of data followed by retrospective data analysis. Patients with isolated ACA stroke served as controls.

Results

Included were 92 patients with isolated ACA and 16 patients with ICA-ACA TO stroke. On univariate analyses, patients with TO had more severe strokes on admission [median NIHSS (IQR) 13.5 (9-21) vs. 8 (5-12), p = 0.003] and were more often treated with thrombectomy (81 vs. 40%, p = 0.002). Mortality rates were higher among TO patients (31 vs. 11%, p = 0.03). Rates of favorable functional outcomes were numerically lower among TO patients (38 vs. 60%) but the difference was not statistically significant (p = 0.09). On multivariate analyses, the presence of TO did not modify the chances for favorable outcomes.

Conclusion

TO stroke with ICA and isolated ACA involvement is rare and results in more severe initial neurological deficits and higher mortality compared to those seen in patients with isolated ACA stroke.

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

BACKGROUND

In 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 angiography (CTA) readings. We aim to evaluate the impact of consistently including CT perfusion (CTP) in admission stroke imaging protocols.

METHODS

From April to October 2020 all patients admitted with a suspected acute ischemic stroke underwent urgent non-contrast CT, CTA and CTP and were treated accordingly. Hypoperfusion areas defined by time-to-maximum of the tissue residue function (Tmax) >6 s, congruent with the clinical symptoms and a vascular territory, were considered VO (CTP-VO). In addition, two experienced neuroradiologists blinded to CTP but not to clinical symptoms retrospectively evaluated non-contrast CT and CTA to identify intracranial VO (CTA-VO).

RESULTS

Of the 338 patients included in the analysis, 157 (46.5%) presented with CTP-VO (median Tmax >6s: 73 (29-127) mL). CTA-VO was identified in 83 (24.5%) of the cases. Overall CTA-VO sensitivity for the detection of CTP-VO was 50.3% and specificity was 97.8%. Higher hypoperfusion volume was associated with increased CTA-VO detection (OR 1.03; 95% CI 1.02 to 1.04). EVT was performed in 103 patients (30.5%; Tmax >6s: 102 (63-160) mL), representing 65.6% of all CTP-VO. Overall CTA-VO sensitivity for the detection of EVT-VO was 69.9% and specificity was 95.3%. Among patients who received EVT, the rate of false negative CTA-VO was 30.1% (Tmax >6s: 69 (46-99.5) mL).

CONCLUSION

Systematically including CTP in acute stroke admission imaging protocols may increase the diagnosis of VO and rate of EVT.

First-Pass Effect Predicts Clinical Outcome and Infarct Growth After Thrombectomy for Distal Medium Vessel Occlusions

BACKGROUND

The first-pass effect in endovascular thrombectomy (EVT) has been associated with better clinical outcomes and decreased stroke progression in large vessel occlusion but has not been evaluated in distal, medium vessel occlusions (DMVOs).

OBJECTIVE

To assess the impact on clinical outcome and stroke progression of the modified first-pass effect (defined as a successful first-pass [modified Thrombolysis In Cerebral Infarction 2b/2c/3] revascularization) in patients who underwent EVT for a primary DMVOs.

METHODS

We collected data from consecutive patients who underwent EVT for a primary DMVO at a single large academic center. We compared the rate of good clinical outcome (modified Rankin Scale of 0-2 at 3 months) and stroke progression between patients who demonstrated modified first-pass effect (mFPE) vs those who did not (no-mFPE).

RESULTS

Between January 2018 and January 2021, we included 60 patients who underwent EVT for an acute ischemic stroke with a primary DMVO. Overall, mFPE was achieved in 32% (19/60) of EVTs. The mFPE was associated with a higher rate of good clinical outcome compared with no-mFPE (89% vs 46%, odds ratio = 16.04 [2.23-115.39], P = .006 in multivariate analysis). Final stroke volume was less among mFPE patients (6.9 mL [4.7-13.6] vs 23 mL [14.6-47], P = .001) as was stroke progression (6.8 mL [4-12.1] vs 17.8 mL [8.1-34.9], P = .016). The mFPE was still associated with higher rates of good clinical outcome when compared with patients reaching an modified Thrombolysis In Cerebral Infarction score ≥2b in more than 1 pass (89% vs 53%; odds ratio = 7.37 [1.43-38.08], P = .017).

CONCLUSION

The mFPE may be associated with better clinical outcomes and lower stroke progression in DMVO.

Spectrum of Large and Medium Vessel Vasculitis in Adults: Primary Vasculitides, Arthritides, Connective Tissue, and Fibroinflammatory Diseases

PURPOSE OF REVIEW

To provide a comprehensive overview of the spectrum of large and medium vessel vasculitis in adults with primary vasculitides, arthritides, connective tissue, and fibroinflammatory diseases as well as vasculitis mimics, for an efficient differential diagnosis and initial diagnostic approach.

RECENT FINDINGS

Imaging has had a tremendous impact on the diagnosis of medium to large vessel vasculitis, now often replacing histopathologic confirmation and identifying new disease manifestations (e.g., intracranial disease in giant cell arteritis; vascular manifestations of IgG4-related disease). Novel diseases or syndromes involving blood vessels have been described (e.g., VEXAS-Syndrome with polychondritis). The use of the terms "medium" or "large" vessel varies considerably between medical specialties. The differential diagnosis of large and medium vessel vasculitis is becoming increasingly complex as new entities or disease manifestations of known inflammatory rheumatic diseases are regularly identified. A more precise and widely recognized definition of the vessel sizes would make future research more comparable.

Effective Dose Measurements of the Latest-Generation Angiographic System in Patients with Acute Stroke: A Comparison with the Newest Multidetector CT Generation

BACKGROUND AND PURPOSE

Patients with acute ischemic stroke are increasingly triaged with one-stop management approaches, resulting in baseline imaging with a flat detector CT scanner. This study aimed to estimate the effective dose to a patient of a novel cervical and intracranial flat detector CT angiography and a flat detector CT perfusion protocol and to compare it with the effective dose of analogous multidetector row CT protocols.

MATERIALS AND METHODS

We estimated the effective dose to the patient according to the International Commission on Radiological Protection 103 using an anthropomorphic phantom with metal oxide semiconductor field effect transistor dosimeters. Placement was according to the organ map provided by the phantom manufacturer. We used 100 measurement points within the phantom, and 18 metal oxide semiconductor field effect transistor dosimeters were placed on the surface of the phantom. All protocols followed the manufacturer's specifications, and patient positioning and collimation were performed as in routine clinical practice. Measurements were obtained on the latest-generation angiography and multidetector row CT systems with identical placement of the metal oxide semiconductor field effect transistor dosimeters.

RESULTS

The estimated effective doses of the investigated perfusion protocols were 4.52 mSv (flat detector CT perfusion without collimation), 2.88 mSv (flat detector CT perfusion with collimation), and 2.17 mSv (multidetector row CT perfusion). A novel protocol called portrait flat detector CT angiography that has a z-axis coverage area comparable with that of multidetector row CT angiography had an estimated effective dose of 0.91 mSv, while the dose from multidetector row CT was 1.35 mSv.

CONCLUSIONS

The estimated effective dose to the patient for flat detector CT perfusion and angiography on a modern biplane angiography system does not deviate substantially from that of analogous multidetector row CT protocols.

First-line thrombectomy strategy for distal and medium vessel occlusions: a systematic review

BACKGROUND

The benefit of mechanical thrombectomy (MT) and efficacy of different first-line MT techniques remain unclear for distal and medium vessel occlusions (DMVOs). In this systematic review, we aimed to compare the performance of three first-line MT techniques in DMVOs.

METHODS

The PubMed database was searched for studies examining the utility of MT in DMVOs (middle cerebral artery M2-3-4, anterior cerebral artery, and posterior cerebral artery). Studies providing data for aspiration thrombectomy (ASP), stent retriever thrombectomy (SR), and combined SR+ASP technique were included. Non-comparative studies were excluded. Safety and efficacy data were collected for each technique. The Nested Knowledge AutoLit platform was utilized for literature search, screening, and data extraction. Pooled data were presented as descriptive statistics.

RESULTS

13 studies comprising 2422 MT procedures were identified. The overall successful recanalization rate was 77.0% (1513/1964) for DMVOs. SR+ASP had a successful recanalization rate of 83.7% (297/355), SR had a 75.6% rate (638/844), while ASP alone had a 74.2% rate (386/520). The overall functional independence rate was 51.3% (851/1659) among DMVOs. The ASP alone group had a functional independence rate of 46.9% (219/467), while functional independence rates of the SR and SR+ASP groups were 51.5% (372/723) and 61.7% (174/282), respectively. Finally, the subarachnoid hemorrhage rates were 1.8% (4/217) for the ASP group, 9.3% (26/281) for the SR group, and 11.9% (41/344) for the SR+ASP group.

CONCLUSIONS

Our systematic review supports the proposition that MT is a safe and effective treatment option for DMVOs. Additionally, while the SR+ASP group had consistently high rates of clot clearance and good neurological outcomes, the SR and SR+ASP groups also had higher rates of subarachnoid hemorrhage, highlighting the need for improved DMVO treatment devices.

Endovascular Therapy vs Medical Management for Patients With Acute Stroke With Medium Vessel Occlusion in the Anterior Circulation

Importance

Randomized clinical trials have shown the efficacy of endovascular therapy (EVT) for acute large vessel occlusion strokes. The benefit of EVT in acute stroke with distal, medium vessel occlusion (DMVO) remains unclear.

Objective

To examine the efficacy and safety outcomes associated with EVT in patients with primary DMVO stroke when compared with a control cohort treated with medical management (MM) alone.

Design, Setting, and Participants

This multicenter, retrospective cohort study pooled data from patients who had an acute stroke and a primary anterior circulation emergency DMVO, defined as any segment of the anterior cerebral artery (ACA) or distal middle cerebral artery, between January 1, 2015, and December 31, 2019. Those with a concomitant proximal occlusion were excluded. Outcomes were compared between the 2 treatment groups using propensity score methods. Data analysis was performed from March to June 2021.

Exposures

Patients were divided into EVT and MM groups.

Main Outcomes and Measures

Main efficacy outcomes included 3-month functional independence (modified Rankin Scale [mRS] scores, 0-2) and 3-month excellent outcome (mRS scores, 0-1). Safety outcomes included 3-month mortality and symptomatic intracranial hemorrhage.

Results

A total of 286 patients with DMVO were evaluated, including 156 treated with EVT (mean [SD] age, 66.7 [13.7] years; 90 men [57.6%]; median National Institute of Health Stroke Scale [NIHSS] score, 13.5 [IQR, 8.5-18.5]; intravenous tissue plasminogen activator [IV tPA] use, 75 [49.7%]; ACA involvement, 49 [31.4%]) and 130 treated with medical management (mean [SD] age, 69.8 [14.9] years; 62 men [47.7%]; median NIHSS score, 7.0 [IQR, 4.0-14.0], IV tPA use, 58 [44.6%]; ACA involvement, 31 [24.0%]). There was no difference in the unadjusted rate of 3-month functional independence in the EVT vs MM groups (151 [51.7%] vs 124 [50.0%]; P = .78), excellent outcome (151 [38.4%] vs 123 [31.7%]; P = .25), or mortality (139 [18.7%] vs 106 [11.3%]; P = .15). The rate of symptomatic intracranial hemorrhage was similar in the EVT vs MM groups (weighted: 4.0% vs 3.1%; P = .90). In inverse probability of treatment weighting propensity analyses, there was no significant difference between groups for functional independence (adjusted odds ratio [aOR], 1.36; 95% CI, 0.84-2.19; P = .20) or mortality (aOR, 1.24; 95% CI, 0.63-2.43; P = .53), whereas the EVT group had higher odds of an excellent outcome (mRS scores, 0-1) at 3 months (aOR, 1.71; 95% CI, 1.02-2.87; P = .04).

Conclusions and Relevance

The findings of this multicenter cohort study suggest that EVT may be considered for selected patients with ACA or distal middle cerebral artery strokes. Further larger randomized investigation regarding the risk-benefit ratio for DMVO treatment is indicated.

Diagnostic Utility of Computed Tomography Perfusion in the Telestroke Setting

BACKGROUND

Definitive diagnosis of acute ischemic stroke is challenging, particularly in telestroke settings. Although the prognostic utility of CT perfusion (CTP) has been questioned, its diagnostic value remains under-appreciated, especially in cases without an easily visible intracranial occlusion. We assessed the diagnostic accuracy of routine CTP in the acute telestroke setting.

METHODS

Acute and follow-up data collected prospectively from consecutive suspected patients with stroke assessed by a state-wide telestroke service between March 2020 and August 2021 at 12 sites in Australia were analyzed. All patients in the final analysis had been assessed with multimodal CT, including CTP, which was post-processed with automated volumetric software. Diagnostic sensitivity and specificity were calculated for multimodal CT and each individual component (noncontrast CT [NCCT], CT angiogram [CTA], and CTP). Final diagnosis determined by consensus review of follow-up imaging and clinical data was used as the reference standard.

RESULTS

During the study period, complete multimodal CT examination was obtained in 831 patients, 457 of whom were diagnosed with stroke. Diagnostic sensitivity for ischemic stroke increased by 19.5 percentage points when CTP was included with NCCT and CTA compared with NCCT and CTA alone (73.1% positive with NCCT+CTA+CTP [95% CI, 68.8-77.1] versus 53.6% positive with NCCT+CTA alone [95% CI, 48.9-58.3], P<0.001). No difference was observed between specificities of NCCT+CTA and NCCT+CTA+CTP (98.7% [95% CI, 98.5-100] versus 98.7% [95% CI, 96.9-99.6], P=0.13). Multimodal CT, including CTP, demonstrated the highest negative predictive value (75.0% [95% CI, 72.1-77.7]). Patients with stroke not evident on CTP had small volume infarcts on follow-up (1.2 mL, interquartile range 0.5-2.7mL).

CONCLUSIONS

Acquisition of CTP as part of a telestroke imaging protocol permits definitive diagnosis of cerebral ischemia in 1 in 5 patients with normal NCCT and CTA.

Novel imaging markers for altered cerebrovascular morphology in aging, stroke, and Alzheimer's disease

BACKGROUND AND PURPOSE

Altered brain vasculature is a key phenomenon in several neurologic disorders. This paper presents a quantitative assessment of the anatomical variations in the Circle of Willis (CoW) and vascular morphology in healthy aging, acute ischemic stroke (AIS) and Alzheimer's Disease (AD).

METHODS

We used our novel automatic method to segment and extract geometric features of the cerebral vasculature from MR angiography scans of 175 healthy subjects, which were used to create a probabilistic atlas of cerebrovasculature and to study normal aging and intersubject variations in CoW anatomy. Subsequently, we quantified and analyzed vascular alterations in 45AIS and 50 AD patients, two prominent cerebrovascular and neurodegenerative disorders.

RESULTS

In the sampled cohort, we determined that the CoW is fully formed in only 35% of healthy adults and found significantly (p < .05) increased tortuosity and fractality, with increasing age and also with disease in both AIS and AD. We also found significantly lower vessel length, volume, and number of branches in AIS patients, as expected. The AD cerebral vessels exhibited significantly smaller diameter and more complex branching patterns, compared to age-matched healthy adults. These changes were significantly heightened (p < .05) among healthy, early onset mild AD, and moderate/severe dementia groups.

CONCLUSION

Although our study does not include longitudinal data due to paucity of such datasets, the specific geometric features and quantitative comparisons demonstrate the potential for using vascular morphology as a noninvasive imaging biomarker for neurologic disorders.

Endovascular treatment for acute ischaemic stroke due to medium vessel occlusion: data from ANGEL-ACT registry

OBJECTIVES

To investigate the safety and efficacy of endovascular treatment (EVT) for acute medium vessel occlusion (MeVO) in the anterior circulation and to explore the independent predictors of the 90-day good outcome for such patients.

METHODS

Data from ANGEL-ACT Registry were analysed in our study. The outcomes, such as the modified Rankin Scale (mRS) at 90 days, successful recanalisation rate and symptomatic intracranial haemorrhage (SICH) rate, were compared between MeVO and acute large vessel occlusions (LVO). Then, the independent predictors of the good outcome at 90 days in MeVO patients were determined by the logistic regression analyses.

RESULTS

We included 1032 subjects in the analysis, of which, 147 were MeVO and 885 were LVO. mRS at 90 days distribution (3 (0-4) vs 3 (0-5), common odds ratio (OR) =1.00, 95% confidence interval (CI) 0.73 to 1.38, p=0.994), SICH rate (4.8% vs 8.9%; OR=0.59, 95% CI 0.26 to 1.34, p=0.205) and successful recanalisation rate (89.8% vs 89.7%; OR=1.00 95% CI 0.51 to 1.93, p=0.992) were similar between the MeVO and LVO groups after adjusting for the confounders. We identified that baseline neutrophil-to-lymphocyte ratio ≤4.1 (OR=2.13, 95% CI 1.14 to 3.99, p=0.019), baseline National Institutes of Health Stroke Scale ≤14 (OR=1.96, 95% CI 1.02 to 3.80, p=0.045) and mechanical thrombectomy passes ≤1 (OR=2.16, 95% CI 1.14 to 4.11, p=0.021) were independent predictors of the 90-day good outcome in MeVO patients undergoing EVT.

CONCLUSIONS

Patients with MeVO achieved similar 90-day mRS, SICH rate and successful recanalisation rate after EVT compared with patients with LVO. Several independent predictors of 90-day good outcome in MeVO patients undergoing EVT were determined, which should be highly considered in MeVO stroke management.

Middle Cerebral Artery M2 Thrombectomy: Safety and Technical Considerations in the German Stroke Registry (GSR)

There is ongoing debate concerning the safety and efficacy of various mechanical thrombectomy (MT) approaches for M2 occlusions. We compared these for MT in M2 versus M1 occlusions. Subgroup analyses of different technical approaches within the M2 MT cohort were also performed. Patients were included from the German Stroke Registry (GSR), a multicenter registry of consecutive MT patients. Primary outcomes were reperfusion success events. Secondary outcomes were early clinical improvement (improvement in NIHSS score > 4) and independent survival at 90 days (mRS 0−2). Out of 3804 patients, 2689 presented with M1 (71%) and 1115 with isolated M2 occlusions (29%). The mean age was 76 (CI 65−82) and 77 (CI 66−83) years, respectively. Except for baseline NIHSS (15 (CI 10−18) vs. 11 (CI 6−16), p < 0.001) and ASPECTS (9 (CI 7−10) vs. 9 (CI 8−10, p < 0.001), baseline demographics were balanced. Apart from a more frequent use of dedicated small vessel stent retrievers (svSR) in M2 (17.4% vs. 3.0; p < 0.001), intraprocedural aspects were balanced. There was no difference in ICH at 24 h (11%; p = 1.0), adverse events (14.4% vs. 18.1%; p = 0.63), clinical improvement (62.5% vs. 61.4 %; p = 0.57), mortality (26.9% vs. 22.9%; p = 0.23). In M2 MT, conventional stent retriever (cSR) achieved higher rates of mTICI3 (54.0% vs. 37.7−42.0%; p < 0.001), requiring more MT-maneuvers (7, CI 2−8) vs. 2 (CI 2−7)/(CI 2−2); p < 0.001) and without impact on efficacy and outcome. Real-life MT in M2 can be performed with equal safety and efficacy as in M1 occlusions. Different recanalization techniques including the use of svSR did not result in significant differences regarding safety, efficacy and outcome.

Adaptive wireless millirobotic locomotion into distal vasculature

Microcatheters have enabled diverse minimally invasive endovascular operations and notable health benefits compared with open surgeries. However, with tortuous routes far from the arterial puncture site, the distal vascular regions remain challenging for safe catheter access. Therefore, we propose a wireless stent-shaped magnetic soft robot to be deployed, actively navigated, used for medical functions, and retrieved in the example M4 segment of the middle cerebral artery. We investigate shape-adaptively controlled locomotion in phantoms emulating the physiological conditions here, where the lumen diameter shrinks from 1.5 mm to 1 mm, the radius of curvature of the tortuous lumen gets as small as 3 mm, the lumen bifurcation angle goes up to 120°, and the pulsatile flow speed reaches up to 26 cm/s. The robot can also withstand the flow when the magnetic actuation is turned off. These locomotion capabilities are confirmed in porcine arteries ex vivo. Furthermore, variants of the robot could release the tissue plasminogen activator on-demand locally for thrombolysis and function as flow diverters, initiating promising therapies towards acute ischemic stroke, aneurysm, arteriovenous malformation, dural arteriovenous fistulas, and brain tumors. These functions should facilitate the robot's usage in new distal endovascular operations.

Worldwide anaesthesia use during endovascular treatment for medium vessel occlusion stroke

INTRODUCTION

The optimal anaesthesia approach for endovascular treatment (EVT) in acute ischaemic stroke is currently unknown. In stroke due to medium vessel occlusions (MeVO), the occluded vessels are particularly small and more difficult to access, especially in restless or uncooperative patients. In these patients, general anaesthesia (GA) may be preferred by physicians to prevent complications due to patient movement. We investigated physicians' approaches to anaesthesia during EVT for MeVO stroke.

METHODS

In a worldwide, case-based, online survey, physicians' preferred anaesthesia approach during EVT for MeVO stroke was categorized as "initial GA", "initial GA if necessary" (depending on patient cooperation), "no initial GA, but conversion if necessary" (start with local anaesthesia or conscious sedation), and "no GA". Preferred anaesthesia approaches were reported overall and stratified by physician and patient characteristics.

RESULTS

A total of 366 survey participants provided 1464 responses to 4 primary MeVO EVT case-scenarios. One-third of responses (489/1464 [33%]) favoured no initial GA, but conversion if necessary. Both initial GA and initial GA if necessary were preferred in 368/1464 (25%) of responses respectively. No GA was favoured in 244/1464 (17%). Occlusion location, respondent specialization (interventional neuroradiology), higher age, and female respondent sex were significantly associated with GA preference. GA was more often used in Europe than in other parts of the world (p < 0.001).

CONCLUSIONS

Anaesthesia approaches in MeVO EVT vary across world regions and patient and physician factors. Most physicians in this survey preferred to start with local anaesthesia or conscious sedation and convert to GA if necessary.

The Anch'Or Harpoon Technique With a Manually Expandable Stentretriever (Tigertriever 13), a Technical Note

Background and purpose

Stent and balloon anchor techniques have been described to obtain distal support and straighten catheter loops, stabilize microcatheters in giant aneurysms, or access distal tortuous anatomy during thrombectomy. These techniques require catheterization of distal arteries with a microcatheter but tortuosity and length issues may render it challenging, precluding the distal unsheathing of a classical auto-expandable stentretriever with the anchor technique.

Methods

Therefore, we developed the so-called Anch'Or Harpoon Technique using a manually expandable stent retriever, the Tigertriever 13 (Rapid Medical, Yoqneam, Israel). Here, the stent retriever is not unsheathed but pushed out of a microcatheter, and then advanced as far as possible before manual opening.

Results and conclusion

This technique may be used in 2 different situations. First, in the case of vessel tortuosity if the microcatheter can't be advanced as far as the physician wants: the Tigertriever 13 could be delivered through the microcatheter without having to unsheathe it, and be advanced and opened distally to its microcatheter to establish a stable anchor prior to advancing the guiding, intermediate, and micro-catheters (Anchor technique). The second situation is when distal occlusions lead to length issues; the microcatheter may be too short to cross a distal clot: the Tigertriever 13 could then be pushed out of the microcatheter, and be used to cross a sub-occlusive clot as it has a soft shaped distal tip and the physician has a visual on the artery beyond the sub-occlusion. Then, the Tigertriever would be manually expanded through the clot and retrieved (Harpoon technique) to obtain a recanalization.

Absence of Perilesional Neuroplastic Recruitment in Chronic Poststroke Aphasia

BACKGROUND AND OBJECTIVES

A prominent theory proposes that neuroplastic recruitment of perilesional tissue supports aphasia recovery, especially when language-capable cortex is spared by smaller lesions. This theory has rarely been tested directly and findings have been inconclusive. We tested the perilesional plasticity hypothesis using 2 fMRI tasks in 2 groups of patients with previous aphasia diagnosis.

METHODS

Two cohorts totaling 82 patients with chronic left-hemisphere stroke with previous aphasia diagnosis and 82 control participants underwent fMRI using either a naming task or a reliable semantic decision task. Individualized perilesional tissue was defined by dilating anatomical lesions and language regions were defined using meta-analyses. Mixed modeling examined differences in activity between groups. Relationships with lesion size and aphasia severity were examined.

RESULTS

Patients exhibited reduced activity in perilesional language tissue relative to controls in both tasks. Although a few cortical regions exhibited greater activity irrespective of distance from the lesion, or only when distant from the lesion, no regions exhibited increased activity only when near the lesion. Larger lesions were associated with reduced language activity irrespective of distance from the lesion. Using the reliable fMRI task, reduced language activity was related to aphasia severity independent of lesion size.

DISCUSSION

We found no evidence for neuroplastic recruitment of perilesional tissue in aphasia beyond its typical role in language. Rather, our findings are consistent with alternative hypotheses that changes in left-hemisphere activation during recovery relate to normalization of language network dysfunction and possibly recruitment of alternate cortical processors. These findings clarify left-hemisphere neuroplastic mechanisms supporting language recovery after stroke.

Silk Vista Baby flow diverter stent for ruptured intracranial aneurysms: a retrospective observational study

PURPOSE

Flow diversion changed the approach to complex intracranial aneurysms, leading to a widespread use and a rapid technological evolution. Indeed, indications continued to expand, including ruptured intracranial aneurysms in selected cases. Recently, new devices have been designed specifically to target smaller vessels. Therefore, we conducted a multicenter study to evaluate clinical outcome, complications, and occlusion rate of patients with ruptured aneurysms treated with new generation low profile Silk Vista Baby (SVB) flow diverter stent (FD).

METHODS

We performed a retrospective observational study on consecutive patients who underwent treatment with SVB for ruptured aneurysms at 12 Italian centers. Primary end point was favorable clinical outcome rate, defined as modified ranking score (mRS) of 0-2 at the 3 months. Secondary outcomes were complication rate, aneurysm re-rupture, and complete aneurysm occlusion at last radiological follow-up.

RESULTS

Twenty-five patients were included; at 3 months' follow-up, 19 patients (79.1%) had favorable clinical outcome (mRS 0-2). Three patients (12.5%) died during follow-up. In-stent thrombosis occurred in two cases (8.3%), managed with glycoprotein IIb/IIIA and intra-stent angioplasty, without clinical consequences. In 18 (85.7%) patients, complete occlusion at 3 months was demonstrated. No rebleeding occurred during follow-up. Presentation with unfavorable World Federation of Neurosurgical Societies grading system (WFNS) and posterior circulation location were both significantly correlated with unfavorable clinical outcome (p = 0.005 and p = 0.02).

CONCLUSIONS

Our data suggests that low profile FD treatment of ruptured intracranial aneurysms located distally of the circle of Willis is feasible. New generation low profile FD may represent an alternative option in carefully selected cases.

A clinically relevant model of focal embolic cerebral ischemia by thrombus and thrombolysis in rhesus monkeys

Over decades of research into the treatment of stroke, nearly all attempts to translate experimental treatments from discovery in cells and rodents to use in humans have failed. The prevailing belief is that it might be necessary to pretest pharmacological neuroprotection in higher-order brains, especially those of nonhuman primates (NHPs). Over the past few years, chemical thrombolysis and mechanical thrombectomy have been established as the standard of care for ischemic stroke in patients. The spotlight is now shifting towards emphasizing both focal ischemia and subsequent reperfusion in developing a clinically relevant stroke model in NHPs. This protocol describes an embolic model of middle cerebral artery occlusion in adult rhesus monkeys. An autologous clot is combined with a microcatheter or microwire through endovascular procedures, and reperfusion is achieved through local intra-artery thrombolysis with tissue plasminogen activator. These NHP models formed relatively stable infarct sizes, delivered predictable reperfusion and survival outcomes, and recapitulated key characteristics of patients with ischemic stroke as observed on MRI images and behavioral assays. Importantly, treated animals could survive 30 d after the surgery for post-stroke neurologic deficit analyses. Thus far, this model has been used in several translational studies. Here we describe in detail the teamwork necessary for developing stroke models of NHPs, including the preoperation preparations, endovascular surgery, postoperation management and histopathological analysis. The model can be established by the following procedures over a 45-d period, including preparation steps (14 d), endovascular operation (1 d) and evaluation steps (30 d).

Endovascular Treatment for Posterior Circulation Stroke: Ways to Maximize Therapeutic Efficacy

The efficacy of endovascular treatment (EVT) in patients with posterior circulation stroke has not been proven. Two recent randomized controlled trials failed to show improved functional outcomes after EVT for posterior circulation stroke (PC-EVT). However, promising results for two additional randomized controlled trials have also been presented at a recent conference. Studies have shown that patients undergoing PC-EVT had a higher rate of futile recanalization than those undergoing EVT for anterior circulation stroke. These findings call for further identification of prognostic factors beyond recanalization. The significance of baseline clinical severity, infarct volume, collaterals, time metrics, core-penumbra mismatch, and methods to accurately measure these parameters are discussed. Furthermore, their interplay on EVT outcomes and the potential to individualize patient selection for PC-EVT are reviewed. We also discuss technical considerations for improving the treatment efficacy of PC-EVT.

Endovascular Therapy versus No Endovascular Therapy in Patients receiving Best Medical Management for Acute Isolated Occlusion of the Posterior Cerebral Artery: Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Endovascular therapy (EVT) is increasingly reported for treatment of isolated posterior cerebral artery (PCA) occlusions although its clinical benefit remains uncertain. This study-level meta-analysis investigated functional outcome and safety of EVT and best medical management (BMM) compared to BMM for treatment of PCA occlusion stroke.

METHODS

We conducted a literature search in PubMed, Web of Science and Embase for articles reporting patients with isolated PCA occlusion stroke treated with EVT+BMM or BMM including intravenous thrombolysis. There were no randomized trials and all studies were retrospective. Primary outcome was a modified Rankin Scale score of 0-2 at 3 months; safety outcomes included mortality rate and incidence of symptomatic intracranial hemorrhage.

RESULTS

Twelve articles with a total of 679 patients were included in the meta-analysis consisting of 338 patients with EVT+BMM and 341 patients receiving BMM alone. Good functional outcome at 3 months was achieved in 58.0% [95% confidence interval (CI) 43.83-70.95] of patients with EVT+BMM and 48.1% [95% CI 40.35-55.92] of patients with BMM with respective mortality rates of 12.6% [7.30-20.93] and 12.3% [8.64-17.33]. Symptomatic intracranial hemorrhage occurred in 4.2% [95% CI 2.47-7.03] of patients with EVT+BMM and 3.2% [95% CI 1.75-5.92] of patients with BMM. Comparative analyses were performed of publications reporting both treatments and demonstrated no significant differences.

CONCLUSIONS

The results demonstrate that EVT represents a safe treatment for patients with isolated PCA occlusion stroke. There were no differences in clinical or safety outcomes between treatments, supporting randomization of future patients into distal vessel occlusion trials.

The End of Tissue-Type Plasminogen Activator's Reign?

Mechanical thrombectomy is a highly effective treatment for acute ischemic stroke caused by large-vessel occlusion in the anterior cerebral circulation, significantly increasing the likelihood of recovery to functional independence. Until recently, whether intravenous thrombolysis before mechanical thrombectomy provided additional benefits to patients with acute ischemic stroke-large-vessel occlusion remained unclear. Given that reperfusion is a key factor for clinical outcome in patients with acute ischemic stroke-large-vessel occlusion and the efficacy of both intravenous thrombolysis and mechanical thrombectomy is time-dependent, achieving complete reperfusion with a single pass should be the primary angiographic goal. However, it remains undetermined whether extending the procedure with additional endovascular attempts or local lytics administration safely leads to higher reperfusion grades and whether there are significant public health and cost implications. Here, we outline the current state of knowledge and research avenues that remain to be explored regarding the consistent therapeutic benefit of intravenous thrombolysis in anterior circulation strokes and the potential place of adjunctive intra-arterial lytics administration, including alternative thrombolytic agent place.

Multiphase CTA-derived tissue maps aid in detection of medium vessel occlusions

PURPOSE

Medium vessel occlusions (MeVOs) can be challenging to detect on imaging. Multiphase computed tomography angiography (mCTA) has been shown to improve large vessel occlusion (LVO) detection and endovascular treatment (EVT) selection. The aims of this study were to determine if mCTA-derived tissue maps can (1) accurately detect MeVOs and (2) predict infarction on 24-h follow-up imaging with comparable accuracy to CT perfusion (CTP).

METHODS

Two readers assessed mCTA tissue maps of 116 ischemic stroke patients (58 MeVOs, 58 non-MeVOs) and determined by consensus: (1) MeVO (yes/no) and (2) occlusion site, blinded to clinical or imaging data. Sensitivity, specificity, and area under the curve (AUC) for MeVO detection were estimated in comparison to reference standards of (1) expert readings of baseline mCTA and (2) CTP maps. Volumetric and spatial agreement between mCTA- and CTP-predicted infarcts was assessed using concordance/intraclass correlation and Dice coefficients. Interrater agreement for MeVO detection on mCTA tissue maps was estimated with Cohen's kappa.

RESULTS

MeVO detection from mCTA-derived tissue maps had a sensitivity of 91% (95% CI: 80-97), specificity of 82% (95% CI: 70-90), and AUC of 0.87 (95% CI: 0.80-0.93) compared to expert reads of baseline mCTA. Interrater reliability was good (0.72, 95% CI: 0.60-0.85). Compared to CTP maps, sensitivity was 87% (95% CI: 75-95), specificity was 78% (95%CI: 65-88), and AUC was 0.83 (95% CI: 0.76-0.90). The mean difference between mCTA- and CTP-predicted final infarct volume was 4.8 mL (limits of agreement: - 58.5 to 68.1) with a Dice coefficient of 33.5%.

CONCLUSION

mCTA tissue maps can be used to reliably detect MeVO stroke and predict tissue fate.

Decision-making strategies for reperfusion therapies: navigating through stroke trials gaps

Despite there being a robust amount of literature and numerous randomized clinical trials regarding acute ischemic stroke treatment, the trials have not included some frequent controversial situations for which decision-making strategies are an urgent and unmet need in clinical practice. This article tries to summarize the current evidence about some selected situations (mechanical thrombectomy in low ASPECTS, low NIHSS with proximal occlusion, acute basilar occlusion, distal and medium vessel occlusion, among others), make suggestions on how to approach them in clinical practice and show what to expect in acute stroke research in the near future.

Aspiration Versus Stent Retriever Thrombectomy for Distal, Medium Vessel Occlusion Stroke in the Posterior Circulation: A Subanalysis of the TOPMOST Study

BACKGROUND

The optimal endovascular strategy for reperfusing distal medium-vessel occlusions (DMVO) remains unknown. This study evaluates angiographic and clinical outcomes of thrombectomy strategies in DMVO stroke of the posterior circulation.

METHODS

TOPMOST (Treatment for Primary Medium Vessel Occlusion Stroke) is an international, retrospective, multicenter, observational registry of patients treated for DMVO between January 2014 and June 2020. This study analyzed endovascularly treated isolated primary DMVO of the posterior cerebral artery in the P2 and P3 segment. Technical feasibility was evaluated with the first-pass effect defined as a modified Thrombolysis in Cerebral Infarction Scale score of 3. Rates of early neurological improvement and functional modified Rankin Scale scores at 90 days were compared. Safety was assessed by the occurrence of symptomatic intracranial hemorrhage and intervention-related serious adverse events.

RESULTS

A total of 141 patients met the inclusion criteria and were treated endovascularly for primary isolated DMVO in the P2 (84.4%, 119) or P3 segment (15.6%, 22) of the posterior cerebral artery. The median age was 75 (IQR, 62-81), and 45.4% (64) were female. The initial reperfusion strategy was aspiration only in 29% (41) and stent retriever in 71% (100), both achieving similar first-pass effect rates of 53.7% (22) and 44% (44; P=0.297), respectively. There were no significant differences in early neurological improvement (aspiration: 64.7% versus stent retriever: 52.2%; P=0.933) and modified Rankin Scale rates (modified Rankin Scale score 0-1, aspiration: 60.5% versus stent retriever 68.6%; P=0.4). In multivariable logistic regression analysis, the time from groin puncture to recanalization was associated with the first-pass effect (adjusted odds ratio, 0.97 [95% CI, 0.95-0.99]; P<0.001) that in turn was associated with early neurological improvement (aOR, 3.27 [95% CI, 1.16-9.21]; P<0.025). Symptomatic intracranial hemorrhage occurred in 2.8% (4) of all cases.

CONCLUSIONS

Both first-pass aspiration and stent retriever thrombectomy for primary isolated posterior circulation DMVO seem to be safe and technically feasible leading to similar favorable rates of angiographic and clinical outcome.

Endovascular Thrombectomy for Distal Medium Vessel Occlusions of the Middle Cerebral Artery: A Safe and Effective Procedure

BACKGROUND

Distal medium vessel occlusions (DMVOs) are increasingly recognized as a next target for endovascular thrombectomy (EVT). Our objective was to investigate safety and clinical outcomes of EVT for DMVO of the middle cerebral artery (MCA).

METHODS

We analyzed data of the Lille Reperfusion Registry from January 2017 to September 2020. Patients with a primary or secondary DMVO of the MCA seen on pretreatment angiogram were included. Only patients with a eTICI score 2b50-2b67 on initial angiogram were considered. Baseline characteristics, angiographic clinical, and safety outcomes were compared between patients treated with EVT or standard medical treatment (no-EVT).

RESULTS

Of the 171 patients included, 96 received EVT (46.9% male, 68.7 ± 15.8 years) and 75 received standard medical treatment (44% male, 73.9 ± 13.1 years). EVT patients had a better improvement of the NIHSS score at discharge (adjusted mean difference: 3.71; 95% CI: 1.18-6.24). In the distal M2 occlusions subgroup, EVT was significantly associated with a higher rate of early neurologic improvement (adjusted OR: 3.62 95% CI: 1.31-10.03), NIHSS improvement at discharge (adjusted mean difference: 5.23; 95% CI: 2.18-8.29), and improved modified Rankin Scale score at 3 months (adjusted common OR for 1 point improvement: 3.06; 95% CI: 1.30 to 7.23). Symptomatic intracranial hemorrhage occurred in 3.1% in the EVT group and in 9.5% in the no-EVT group.

CONCLUSIONS

EVT for DMVO of the MCA appears to be safe and may lead to improved clinical outcomes. This effect was especially pronounced in patients with distal M2 occlusions, warranting randomized trials to validate this result.

Association of reperfusion success and emboli in new territories with long term mortality after mechanical thrombectomy

BACKGROUND

The degree of reperfusion is the most important modifiable predictor of 3 month functional outcome and mortality in ischemic stroke patients treated with mechanical thrombectomy. Whether the beneficial effect of reperfusion also leads to a reduction in long term mortality is unknown.

METHODS

Patients undergoing mechanical thrombectomy between January 2010 and December 2018 were included. The post-thrombectomy degree of reperfusion and emboli in new territories were core laboratory adjudicated. Reperfusion was evaluated according to the expanded Thrombolysis in Cerebral Infarction (eTICI) scale. Vital status was obtained from the Swiss population register. Adjusted hazard ratios (aHRs) using time split Cox regression models were calculated. Subgroup analyses were performed in patients with borderline indications.

RESULTS

Our study included 1264 patients (median follow-up per patient 2.5 years). Patients with successful reperfusion had longer survival times, attributable to a lower hazard of death within 0-90 days and for >90 days to 2 years (aHR 0.34, 95% CI 0.26 to 0.46; aHR 0.37, 95% CI 0.22 to 0.62). This association was homogeneous across all predefined subgroups (p for interaction >0.05). Among patients with successful reperfusion, a significant difference in the hazard of death was observed between eTICI2b50 and eTICI3 (aHR 0.51, 95% CI 0.33 to 0.79). Emboli in new territories were present in 5% of patients, and were associated with increased mortality (aHR 2.3, 95% CI 1.11 to 4.86).

CONCLUSION

Successful, and ideally complete, reperfusion without emboli in new territories is associated with a reduction in long term mortality in patients treated with mechanical thrombectomy, and this was evident across several subgroups.

Suction thrombectomy using a microcatheter as a salvage method for acute distal occlusion during cerebral aneurysm embolization: A case report

The aneurysm coiling process presents a risk of thromboembolic complications, mostly in patients with ruptured aneurysms, given the fact that they cannot receive antiplatelet therapy. Management strategies include medical anticoagulation or antiplatelet therapy, intra-arterial thrombolysis, and mechanical thrombectomy using direct aspiration first-pass technique or stent retrievers. We report our own experience of using an Excelsior SL-10 Microcatheter (Stryker, Fremont, California, USA) with an internal diameter of 0.0165”, originally designed for coil delivery, for contact aspiration of a thrombotic occlusion of a distal anterior cerebral artery during coiling of a broad-based trilobar anterior communicating artery aneurysm. The clot was removed under continuous manual aspiration, and complete recanalization has been accomplished. Mechanical thrombectomy through microcatheter aspiration may be a safe and feasible treatment option for acute distal artery occlusions, especially in the case of tortuous distal vessels during embolization of cerebral aneurysms.

Accuracy of CTA evaluations in daily clinical practice for large and medium vessel occlusion detection in suspected stroke patients

INTRODUCTION

Early detection of large vessel occlusion (LVO) is essential to facilitate fast endovascular treatment. CT angiography (CTA) is used to detect LVO in suspected stroke patients. We aimed to assess the accuracy of CTA evaluations in daily clinical practice in a large cohort of suspected stroke patients.

PATIENTS AND METHODS

We used data from the PRESTO study, a multicenter prospective observational cohort study that included suspected stroke patients between August 2018 and September 2019. Baseline CTAs were re-evaluated by an imaging core laboratory and compared to the local assessment. LVO was defined as an occlusion of the intracranial internal carotid artery, M1 segment, or basilar artery. Medium vessel occlusion (MeVO) was defined as an A1, A2, or M2 occlusion. We calculated the accuracy, sensitivity, and specificity to detect LVO and LVO+MeVO, using the core laboratory evaluation as reference standard.

RESULTS

We included 656 patients. The core laboratory detected 89 LVOs and 74 MeVOs in 155 patients. Local observers missed 6 LVOs (7%) and 28 MeVOs (38%), of which 23 M2 occlusions. Accuracy of LVO detection was 99% (95% CI: 98-100%), sensitivity 93% (95% CI: 86-97%), and specificity 100% (95% CI: 99-100%). Accuracy of LVO+MeVO detection was 95% (95% CI: 93-96%), sensitivity 79% (95% CI: 72-85%), and specificity 99% (95% CI: 98-100%).

DISCUSSION AND CONCLUSION

CTA evaluations in daily clinical practice are highly accurate and LVOs are adequately recognized. The detection of MeVOs seems more challenging. The evolving EVT possibilities emphasize the need to improve CTA evaluations in the acute setting.

Predictors and Prognostic Implications of Hemorrhagic Transformation Following Cerebral Endovascular Thrombectomy in Acute Ischemic Stroke: A Multicenter Analysis

PURPOSE

Hemorrhagic transformation (HT) following cerebral endovascular thrombectomy (EVT) for large vessel occlusion (LVO) in acute ischemic stroke is associated with poor outcome. Recent studies have shown that EVT can be efficacious in imaging-selected patients as late as 6-24 h from onset (late time window; LTW). We sought to determine predictors and prognostic implications of HT following EVT in LTW.

METHODS

Consecutive patients undergoing EVT for LVO were recruited into a prospective multicenter database. HT was divided into petechial hemorrhagic-infarction and parenchymal hematoma (PH) type 1 or 2 defined as confluent hemorrhage covering < or > than 1/3 of the infarct volume, respectively. Multivariate analyses were performed to determine variables associated with HT subtypes.

RESULTS

Among 611 patients included (mean age 70.5 ± 12.5 years; median NIHSS 16), 115 (18.8%) had HT and 33 of them (5.4%) had PH2. Independent PH2 predictors included failed recanalization (OR 7.0, 95% CI 2.3-21.6), longer time from symptom onset to admission (OR 1.002 per minute 95% CI 1.001-1.003) and hyperlipidemia (OR 3.12; 95%CI 1.12-8.7). HT was not associated with outcome. In contrast, PH2 patients had lower favorable outcome rates (14.3 vs 41.6%, p = 0.004) and higher mortality rates (39 vs 17%, p = 0.001). Patients who underwent EVT in the late versus early window had similar PH2 rates (4.5 vs 6.7%, p = 0.27). In multivariate models, PH2 tripled the odds of both 90-day poor outcome (OR 3.1, 95% CI 1.01-9.5) and 90-day mortality (OR 3.2, 95% CI 1.4-7.3).

CONCLUSIONS

PH2 following EVT is associated with increased mortality and unfavorable outcome rates. Rates of PH2 are not different between LTW patients and those treated < 6 h from symptom onset.

Early Neurological Improvement Predicts Clinical Outcome After Thrombectomy for Distal Medium Vessel Occlusions

Background and Purpose

Good clinical outcome predictors have been established in mechanical thrombectomy (MT) for acute ischemic stroke (AIS) caused by large vessel occlusion (LVO). An early neurological improvement (ENI), defined as a reduction of ≥8 on the National Institutes of Health Stroke Scale (NIHSS), compared with the baseline score or an NIHSS of 0 or 1 at 24 h after MT, is a strong predictor of favorable outcome. We aimed to study the impact of ENI after MT for distal medium vessel occlusions (DMVO).

Methods

We retrospectively analyzed the data of consecutive patients who underwent MT for a primary DMVO in one large academic center. We compared clinical outcomes between patients with DMVO stratified by ENI. Multivariate analyses were performed to determine the impact of ENI on good 90-day outcome (modified Rankin scale of 0–2) and identify factors contributing to ENI.

Results

Between January 2018 and January 2021, 61 patients underwent an MT for an AIS with a primary DMVO. An ENI was seen in 24 (39%) patients (ENI+). Outcomes were significantly better in ENI+ patients, with 83% achieving a good outcome at 3 months vs. 43% for patients without ENI (ENI–; p = 0.019). ENI was an independent predictive factor of good clinical outcome even after adjusting for potential confounding factors [odds ratio 12.49 (1.49–105.01), p = 0.020]. The use of intravenous tissue plasminogen activator [IVtPA; Odds-ratio 6.59 (1.82–23.89), p = 0.004] was a positive predictor of ENI.

Conclusion

ENI at day 1 following MT for DMVO stroke is a strong independent predictor of good to excellent 3-month clinical outcome.

Endovascular thrombectomy for acute ischemic stroke

This review describes the evolution of endovascular treatment for acute ischemic stroke, current state of the art, and the challenges for the next decade. The rapid development of endovascular thrombectomy (EVT), from the first attempts into standard of care on a global scale, is one of the major achievements in modern medicine. It was possible thanks to the establishment of a scientific framework for patient selection, assessment of stroke severity and outcome, technical development by dedicated physicians and the MedTech industry, including noninvasive imaging for patient selection, and radiological outcome evaluation. A series of randomized controlled trials on EVT in addition to intravenous thrombolytics, with overwhelmingly positive results for anterior circulation stroke within 6 h of onset regardless of patient characteristics with a number needed to treat of less than 3 for any positive shift in outcome, paved the way for a rapid introduction of EVT into clinical practice. Within the "extended" time window of 6-24 h, the effect has been even greater for patients with salvageable brain tissue according to perfusion imaging with a number needed to treat below 2. Even so, EVT is only available for a small portion of stroke patients, and successfully recanalized EVT patients do not always achieve excellent functional outcome. The major challenges in the years to come include rapid prehospital detection of stroke symptoms, adequate clinical and radiological diagnosis of severe ischemic stroke cases, enabling effective recanalization by EVT in dedicated angiosuites, followed by personalized post-EVT stroke care.