Intra-Arterial Thrombolysis is Associated with Delayed Reperfusion of Remaining Vessel Occlusions following Incomplete Thrombectomy.

BACKGROUND AND PURPOSE: Intra-arterial thrombolytics may be used to treat distal vessel occlusions, which cause incomplete reperfusion following mechanical thrombectomy. Because immediate reperfusion after intra-arterial thrombolytics occurs rarely, the aim of this study was to assess the delayed effect of intra-arterial thrombolytics using follow-up perfusion imaging. MATERIALS AND METHODS: We included patients from a prospective stroke registry (February 2015 to September 2022) who had undergone mechanical thrombectomy and had incomplete reperfusion (expanded TICI 2a-2c) and available 24 hour perfusion imaging. Perfusion imaging was rated as delayed reperfusion if time-sensitive perfusion maps did not show wedge-shaped delays suggestive of persisting occlusions corresponding to the post-mechanical thrombectomy angiographic deficit. Patients treated with intra-arterial thrombolytics were compared with controls using multivariable logistic regression and inverse probability of treatment weighting matching for baseline differences and factors associated with delayed reperfusion. RESULTS: The median age of the final study population (n = 459) was 74 years (interquartile range, 63-81 years), and delayed reperfusion occurred in 61% of cases. Patients treated with additional intra-arterial thrombolytics (n = 40) were younger and had worse expanded TICI scores. After matching was performed, intra-arterial thrombolytics was associated with higher rates of delayed reperfusion (adjusted OR = 2.7; 95% CI, 1.1-6.4) and lower rates of new infarction in the residually hypoperfused territory after mechanical thrombectomy (adjusted OR = 0.3; 95% CI, 0.1-0.7). No difference was found in the rates of functional independence (90-day mRS, 0-2; adjusted OR = 1.4; 95% CI, 0.4-4.1). CONCLUSIONS: Rescue intra-arterial thrombolytics is associated with delayed reperfusion of remaining vessel occlusions following incomplete mechanical thrombectomy. The value of intra-arterial thrombolytics as a potential therapy for incomplete reperfusions after mechanical thrombectomy should be assessed in the setting of randomized controlled trials.

Endovascular therapy outcome in isolated posterior cerebral artery occlusion strokes: A multicenter analysis of the Swiss Stroke Registry.

PURPOSE: There is little data on the safety and efficacy of endovascular treatment (EVT) in comparison with intravenous thrombolysis (IVT) in acute ischemic stroke due to isolated posterior cerebral artery occlusion (IPCAO). We aimed to investigate the functional and safety outcomes of stroke patients with acute IPCAO treated with EVT (with or without prior bridging IVT) compared to IVT alone. METHODS: We did a multicenter retrospective analysis of data from the Swiss Stroke Registry. The primary endpoint was overall functional outcome at 3 months in patients undergoing EVT alone or as part of bridging, compared with IVT alone (shift analysis). Safety endpoints were mortality and symptomatic intracranial hemorrhage. EVT and IVT patients were matched 1:1 using propensity scores. Differences in outcomes were examined using ordinal and logistic regression models. FINDINGS: Out of 17,968 patients, 268 met the inclusion criteria and 136 were matched by propensity scores. The overall functional outcome at 3 months was comparable between the two groups (EVT vs IVT as reference category: OR = 1.42 for higher mRS, 95% CI = 0.78-2.57, p = 0.254). The proportion of patients independent at 3 months was 63.2% in EVT and 72.1% in IVT (OR = 0.67, 95% CI = 0.32-1.37, p = 0.272). Symptomatic intracranial hemorrhages were overall rare and present only in the IVT group (IVT = 5.9% vs EVT = 0%). Mortality at 3 months was also similar between the two groups (IVT = 0% vs EVT = 1.5%). CONCLUSION: In this multicenter nested analysis, EVT and IVT in patients with acute ischemic stroke due to IPCAO were associated with similar overall good functional outcome and safety. Randomized studies are warranted.

Correlation of Collateral Scores Derived from Whole-Brain Time-Resolved Flat Panel Detector Imaging in Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: Flat panel detector CT imaging allows simultaneous acquisition of multiphase flat panel CTA and flat panel CTP imaging directly in the angio suite. We compared collateral assessment derived from multiphase flat panel CTA and flat panel CTP with collateral assessment derived from DSA as the gold-standard. MATERIALS AND METHODS: We performed a retrospective analysis of patients with occlusion of the first or second segment of the MCA who underwent pre-interventional flat panel detector CT. The hypoperfusion intensity ratio as a correlate of collateral status was calculated from flat panel CTP (time-to-maximum > 10 seconds volume/time-to-maximum > 6 seconds volume). Intraclass correlation coefficients were calculated for interrater reliability for the Calgary/Menon score for multiphase flat panel CTA and for the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) score for DSA collateral scores. Correlations of the hypoperfusion intensity ratio, multiphase flat panel CTA score, and the ASITN/SIR score were calculated using the Spearman correlation. RESULTS: From November 2019 to February 2020, thirty patients were included. Moderate interrater reliability was achieved for the ASITN/SIR DSA score (0.68; 95% CI, 0.50-0.82) as well as for the Calgary/Menon multiphase flat panel CTA score (0.53; 95% CI, 0.29-0.72). We found a strong correlation between the ASITN/SIR DSA and Calgary/Menon multiphase flat panel CTA score (ρ = 0.54, P = .002) and between the hypoperfusion intensity ratio and the Calgary/Menon multiphase flat panel CTA score (ρ = -0.57, P < .001). The correlation was moderate between the hypoperfusion intensity ratio and the ASITN/SIR DSA score (ρ = -0.49, P = .006). The infarct core volume correlated strongly with the Calgary/Menon multiphase flat panel CTA score (ρ = -0.66, P < .001) and the hypoperfusion intensity ratio (ρ = 0.76, P < .001) and correlated moderately with the ASITN/SIR DSA score (ρ = -0.46, P = .01). CONCLUSIONS: The Calgary/Menon multiphase flat panel CTA score and the hypoperfusion intensity ratio correlated with each other and with the ASITN/SIR DSA score as the gold-standard. In our cohort, the collateral scoring derived from flat panel detector CT was clinically reliable.

Risks of Undersizing Stent Retriever Length Relative to Thrombus Length in Patients with Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: Results regarding the association of thrombus length, stent retriever length, and recanalization success in patients with acute ischemic stroke are inconsistent. We hypothesized that the ratio of thrombus length to stent retriever length may be of particular relevance. MATERIALS AND METHODS: Patients with acute ischemic stroke undergoing stent retriever thrombectomy at our institution between January 2010 and December 2018 were reviewed retrospectively. Thrombus length was assessed by measuring the susceptibility vessel sign on SWI using a 1.5T or 3T MR imaging scanner. Multivariable logistic regression models were used to determine the association between thrombus length, stent retriever length, and thrombus length/stent retriever length ratio with first-pass recanalization, overall recanalization, and embolization in new territories. Results are shown as adjusted ORs with 95% CIs. Additional mediation analyses were performed to test for indirect effects on first-pass recanalization and overall recanalization success. RESULTS: The main analysis included 418 patients (mean age, 74.9 years). Increasing stent retriever length was associated with first-pass recanalization. Decreasing thrombus length and lower thrombus length/stent retriever length ratios were associated with first-pass recanalization and overall recanalization. Thrombus length and stent retriever length showed no association with first-pass recanalization or overall recanalization once thrombus length/stent retriever length ratio was factored in, while thrombus length/stent retriever length ratio remained a significant factor in both models (adjusted OR, 0.316 [95% CI, 0.112-0.892]; P = .030 and adjusted OR, = 0.366 [95% CI, 0.194-0.689]; P = .002). Mediation analyses showed that decreasing thrombus length and increasing stent retriever length had a significant indirect effect on first-pass recanalization mediated through thrombus length/stent retriever length ratio. The only parameter associated with embolization in new territories was an increasing thrombus length/stent retriever length ratio (adjusted OR, 5.079 [95% CI, 1.332-19.362]; P = .017). CONCLUSIONS: Information about thrombus and stent length is more valuable when combined. High thrombus length/stent retriever length ratios, which may raise the risk of unsuccessful recanalization and embolization in new territories, should be avoided by adapting stent retriever selection to thrombus length whenever possible.

SWI Susceptibility Vessel Sign in Patients Undergoing Mechanical Thrombectomy for Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: The frequency and clinical significance of the susceptibility vessel sign in patients with acute ischemic stroke remains unclear. We aimed to assess its prevalence in patients with acute ischemic stroke undergoing mechanical thrombectomy and to analyze its association with interventional and clinical outcome parameters in that group. MATERIALS AND METHODS: Six hundred seventy-six patients with acute ischemic stroke and admission MR imaging were reviewed retrospectively. Of those, 577 met the eligibility criteria for further analysis. Imaging was performed using a 1.5T or 3T MR imaging scanner. Associations between baseline variables, interventional and clinical outcome parameters, and susceptibility vessel sign were determined with multivariable logistic regression models. Results are shown as adjusted ORs with 95% CIs. RESULTS: The susceptibility vessel sign was present in 87.5% (n = 505) of patients and associated with tandem occlusion (adjusted OR, 3.3; 95% CI, 1.1-10.0; P = .032) as well as successful reperfusion, defined as an expanded TICI score of ≥2b (adjusted OR, 2.4; 95% CI, 1.28-4.6; P = .007). The susceptibility vessel sign was independently associated with functional independence (mRS ≤ 2: adjusted OR, 2.1; 95% CI, 1.1-4.0; P = .028) and lower mortality (adjusted OR, 0.4; 95% CI, 0.2-0.7; P = .003) at 90 days, even after adjusting for successful reperfusion. The susceptibility vessel sign did not influence the number of passes performed during mechanical thrombectomy, the first-pass reperfusion, or the risk of peri- or postinterventional complications. CONCLUSIONS: The susceptibility vessel sign is an MR imaging phenomenon frequently observed in patients with acute ischemic stroke and is associated with successful reperfusion after mechanical thrombectomy. However, superior clinical functional outcome and lower mortality noted in patients showing the susceptibility vessel sign could not be entirely attributed to higher reperfusion rates.

Evolution of MRI Findings in Patients with Idiopathic Intracranial Hypertension after Venous Sinus Stenting.

BACKGROUND AND PURPOSE: The correlation between imaging findings and clinical status in patients with idiopathic intracranial hypertension is unclear. We aimed to examine the evolution of idiopathic intracranial hypertension-related MR imaging findings in patients treated with venous sinus stent placement. MATERIALS AND METHODS: Thirteen patients with idiopathic intracranial hypertension (median age, 26.9 years) were assessed for changes in the CSF opening pressure, transstenotic pressure gradient, and symptoms after venous sinus stent placement. Optic nerve sheath diameter, posterior globe flattening and/or optic nerve protrusion, empty sella, the Meckel cave, tonsillar ectopia, the ventricles, the occipital emissary vein, and subcutaneous fat were evaluated on MR imaging before and 6 months after venous sinus stent placement. Data are expressed as percentages, medians, or correlation coefficients (r) with P values. RESULTS: Although all patients showed significant reductions of the CSF opening pressure (31 versus 21 cm H2O; P = .005) and transstenotic pressure gradient (22.5 versus 1.5 mm Hg; P = .002) and substantial improvement of clinical symptoms 6 months after venous sinus stent placement, a concomitant reduction was observed only for posterior globe involvement (61.5% versus 15.4%; P = .001), optic nerve sheath diameter (6.8 versus 6.1 mm; P < .001), and subcutaneous neck fat (8.9 versus 7.4 mm; P = .001). Strong correlations were observed between decreasing optic nerve sheath diameters and improving nausea/emesis (right optic nerve sheath diameter, r = 0.592, P = .033; left optic nerve sheath diameter, r = 0.718, P = .006), improvement of posterior globe involvement and decreasing papilledema (r = 0.775, P = .003), and decreasing occipital emissary vein diameter and decreasing headache frequency (r = 0.74, P = .035). Decreasing transstenotic pressure gradient at 6 months strongly correlated with decreasing empty sella (r = 0.625, P = .022) and regressing cerebellar ectopia (r = 0.662, P = .019). CONCLUSIONS: Most imaging findings persist long after normalization of intracranial pressure and clinical improvement. However, MR imaging findings related to the optic nerve may reflect treatment success.

Basal Ganglia versus Peripheral Infarcts: Predictive Value of Early Fiber Alterations.

BACKGROUND AND PURPOSE: Impairment of fiber integrity of the corticospinal tract in the subacute and chronic phases after ischemic stroke has been linked to poor motor outcome. The aim of the study was an assessment of fiber integrity in the acute poststroke phase and an evaluation of its association with the clinical course dependent on the infarction pattern (subtypes: peripheral versus basal ganglia infarction). MATERIALS AND METHODS: All patients who underwent mechanical recanalization of a large-vessel occlusion in the anterior circulation and postinterventional DTI were included (n = 165). The fractional anisotropy index of the patient-specific corticospinal tract within the posterior limb of the internal capsule was correlated to clinical parameters (NIHSS scores/mRS at 90 days), and the interaction of stroke subtype (peripheral infarcts versus basal ganglia infarction) was tested in a moderation analysis. RESULTS: The fractional anisotropy index was reduced in the acute poststroke phase with a correlation to clinical presentation, especially in case of peripheral infarcts (eg, with the NIHSS motor subscore: r = -0.4, P < .001). This correlation was absent for basal ganglia infarction (r = -0.008, P > .05). There was a significant association between the fractional anisotropy index and clinical outcome (mRS after 90 days, P < .01), which is moderated by stroke subtype with significant effects only for peripheral infarcts. CONCLUSIONS: Corticospinal tract abnormalities can be observed in the early stage after mechanical recanalization and have prognostic capacity. This finding increases the clinical value of early DTI imaging parameters. Because the effects observed were limited to peripheral infarcts, further and longitudinal evaluation of fiber integrities within basal ganglia infarction is required.

A short history of thrombectomy - Procedure and success analysis of different endovascular stroke treatment techniques.

BACKGROUND: The historical development of interventional stroke treatment shows a wide variation of different techniques and materials used. Thus, the question of the present work is whether the technical and procedural differences of thrombectomy techniques lead to different technical and clinical results. METHODS AND RESULTS: Analysis of a mixed retrospective/prospective database of all endovascular treated patients with an occlusion of the Carotid-T or M1 segment of the MCA at a single comprehensive stroke center since 2008. Patients were classified regarding the technical approach used. Six hundred sixty-eight patients were available for the final analysis. Reperfusion rates ranged between 56% and 100% depending on the technical approach. The use of balloon guide catheters and most recently the establishment of combination techniques using balloon guide catheters, aspiration catheters and stent retrievers have shown a further significant increase in the rates of successful recanalization, full recanalization and first-pass recanalization. Additionally, the technical development of interventional techniques has led to a subsequent drop in complications, embolization into previously unaffected territories in particular. CONCLUSION: Technical success of MT has improved substantially over the past decade owing to improved materials and procedural innovations. Combination techniques including flow modulation have emerged to be the most effective approach and should be considered as a standard of care.Level of evidence: Level 3, retrospective study.

Spine MRI in Spontaneous Intracranial Hypotension for CSF Leak Detection: Nonsuperiority of Intrathecal Gadolinium to Heavily T2-Weighted Fat-Saturated Sequences.

BACKGROUND AND PURPOSE: Spine MR imaging plays a pivotal role in the diagnostic work-up of spontaneous intracranial hypotension. The aim of this study was to compare the diagnostic accuracy of unenhanced spine MR imaging and intrathecal gadolinium-enhanced spine MR imaging for identification and localization of CSF leaks in patients with spontaneous intracranial hypotension. MATERIALS AND METHODS: A retrospective study of patients with spontaneous intracranial hypotension examined from February 2013 to October 2017 was conducted. Their spine MR imaging was reviewed by 3 blinded readers for the presence of epidural CSF using 3 different sequences (T2WI, 3D T2WI fat-saturated, T1WI gadolinium). In patients with leaks, the presumed level of the leak was reported. RESULTS: In total, 103 patients with spontaneous intracranial hypotension (63/103 [61%] women; mean age, 50 years) were evaluated. Seventy had a confirmed CSF leak (57/70 [81%] proved intraoperatively), and 33 showed no epidural CSF on multimodal imaging. Intrathecal gadolinium-enhanced spine MR imaging was nonsuperior to unenhanced spine MR imaging for the detection of epidural CSF (P = .24 and .97). All MR imaging sequences had a low accuracy for leak localization. In all patients, only 1 leakage point was present, albeit multiple suspicious lesions were reported in all sequences (mean, 5.0). CONCLUSIONS: Intrathecal gadolinium-enhanced spine MR imaging does not improve the diagnostic accuracy for the detection of epidural CSF. Thus, it lacks a rationale to be included in the routine spontaneous intracranial hypotension work-up. Heavily T2-weighted images with fat saturation provide high accuracy for the detection of an epidural CSF collection. Low accuracy for leak localization is due to an extensive CSF collection spanning several vertebrae (false localizing sign), lack of temporal resolution, and a multiplicity of suspicious lesions, albeit only a single leakage site is present. Thus, dynamic examination is mandatory before targeted treatment is initiated.

Etiology of recurrent large vessel occlusions treated with repeated thrombectomy.

BACKGROUND: Repeated mechanical thrombectomy for acute stroke treatment in individual patients has been proven feasible. However, less is known about the etiology of recurrent vessel occlusions after prior thrombectomy. We aimed to understand if the etiology of such recurrent events differs from the first stroke. METHODS: Retrospectively, we identified all patients at our center who received a repeated mechanical thrombectomy between 2007 and 2019. Clinical data were retrieved from medical records. Etiology of stroke was evaluated retrospectively, and angiographic studies were revisited. RESULTS: Twenty-three patients (1.5%) were identified. Median age was 68 years (IQR 56-77). Median NIHSS at first admission was 11 points (IQR 5-15). In nine cases (39.1%), the recurrent vessel occlusion was located exactly at the same position as the prior occlusion. Overall, five (21.7%) patients had a remarkable extracranial pathology as likely cause of stroke recurrence. In 16 patients (69.6%), the etiology of the first stroke and its recurrence was considered as likely being the same, mostly of cardioembolic or unknown origin. In the seven remaining patients (30.4%), the cause of stroke possibly differed from the first event, with five patients (21.7%) having a postinterventional intracranial intimal lesion as possible cause of stroke. CONCLUSION: Incidence of repeated thrombectomy was low. However, the high number of patients with known origin of stroke etiology raises the question how their monitoring may be optimized. The number of patients with remarkable extracranial pathologies or intracranial endothelial lesions supports current clinical practice to pay attention to final angiographic series.

Microstructural Integrity of Salvaged Penumbra after Mechanical Thrombectomy.

BACKGROUND AND PURPOSE: There are sparse data on the microstructural integrity of salvaged penumbral tissue after mechanical thrombectomy of large-vessel occlusions. The aim of the study was to analyze possible microstructural alteration in the penumbra and their association with clinical symptoms as well as angiographic reperfusion success in patients undergoing mechanical thrombectomy. MATERIALS AND METHODS: All patients who underwent mechanical thrombectomy for large-vessel occlusions in the anterior circulation and who received an admission CT perfusion together with postinterventional DTIs were included (n = 65). Angiographic reperfusion success by means of modified Thrombolysis in Cerebral Infarction (mTICI) scale and clinical outcome were recorded. Microstructural integrity was assessed by DTI evaluating the mean diffusivity index within the salvaged gray matter of the former penumbra. RESULTS: The mean diffusivity index was higher in completely recanalized patients (mTICI 3: -0.001 ± 0.034 versus mTICI <3: -0.030 ± 0.055, P = .03). There was a positive correlation between the mean diffusivity index and NIHSS score improvement (r = 0.49, P = .003) and the mean diffusivity index was associated with midterm functional outcome (r = -0.37, P = .04) after adjustment for confounders. In mediation analysis, the mean diffusivity index and infarction growth mediated the association between reperfusion success and clinical outcomes. CONCLUSIONS: The macroscopic salvaged penumbra included areas of microstructural integrity changes, most likely related to the initial hypoperfusion. These abnormalities were found early after mechanical thrombectomy, were dependent on angiographic results, and correlated with the clinical outcome. When confirmed, these findings prompt the evaluation of therapies for protection of the penumbral tissue integrity.

Opportunistic osteoporosis screening in multi-detector CT images via local classification of textures.

Our study proposed an automatic pipeline for opportunistic osteoporosis screening using 3D texture features and regional vBMD using multi-detector CT images. A combination of different local and global texture features outperformed the global vBMD and showed high discriminative power to identify patients with vertebral fractures. INTRODUCTION: Many patients at risk for osteoporosis undergo computed tomography (CT) scans, usable for opportunistic (non-dedicated) screening. We compared the performance of global volumetric bone mineral density (vBMD) with a random forest classifier based on regional vBMD and 3D texture features to separate patients with and without osteoporotic fractures. METHODS: In total, 154 patients (mean age 64 ± 8.5, male; n = 103) were included in this retrospective single-center analysis, who underwent contrast-enhanced CT for other reasons than osteoporosis screening. Patients were dichotomized regarding prevalent vertebral osteoporotic fractures (noFX, n = 101; FX, n = 53). Vertebral bodies were automatically segmented, and trabecular vBMD was calculated with a dedicated phantom. For 3D texture analysis, we extracted gray-level co-occurrence matrix Haralick features (HAR), histogram of gradients (HoG), local binary patterns (LBP), and wavelets (WL). Fractured vertebrae were excluded for texture-feature and vBMD data extraction. The performance to identify patients with prevalent osteoporotic vertebral fractures was evaluated in a fourfold cross-validation. RESULTS: The random forest classifier showed a high discriminatory power (AUC = 0.88). Parameters of all vertebral levels significantly contributed to this classification. Importantly, the AUC of the proposed algorithm was significantly higher than that of volumetric global BMD alone (AUC = 0.64). CONCLUSION: The presented classifier combining 3D texture features and regional vBMD including the complete thoracolumbar spine showed high discriminatory power to identify patients with vertebral fractures and had a better diagnostic performance than vBMD alone.

Reasons for Reperfusion Failures in Stent-Retriever-Based Thrombectomy: Registry Analysis and Proposal of a Classification System.

BACKGROUND AND PURPOSE: In 5%-10% of patients with acute ischemic stroke with an intention to treat with mechanical thrombectomy, no reperfusion can be achieved (Thrombolysis in Cerebral Infarction score = 0/1). Purpose of this analysis was a systematic assessment of underlying reasons for reperfusion failures. MATERIALS AND METHODS: An intention-to-treat single-center cohort (n = 592) was re-evaluated for all patients in whom no reperfusion could be achieved (n = 63). Baseline characteristics of patients were compared between patients with and without reperfusion failures. After qualitative review of all cases with reperfusion failures, a classification system was proposed and relative frequencies were reported. In a second step, occurrence of delayed recanalization at 24 hours after reperfusion failure and dependency on IV-tPA were evaluated. RESULTS: In 63/592 patients with an intention to perform stent-retriever thrombectomy, no reperfusion was achieved (TICI 0/1, 10.6%, 95% CI, 8.2%-13.1%). Older patients (adjusted OR per yr = 1.03; 95% CI, 1.01-1.05) and patients with M2 occlusion (adjusted OR = 3.36; 95% CI, 1.82-6.21) were at higher risk for reperfusion failure. In most cases, no reperfusion was a consequence of technical difficulties (56/63, 88.9%). In one-third of these cases, reperfusion failures were due to the inability to reach the target occlusion (20/63, 31.7%), while "stent-retriever failure" occurred in 39.7% (25/63) of patients. Delayed recanalization was very rare (18.2%), without dependence on IV-tPA pretreatment status. CONCLUSIONS: Reasons for reperfusion failure in stent-retriever thrombectomy are heterogeneous. The failure to establish intracranial or cervical access is almost as common as stent-retriever failure after establishing intracranial access. Systematic reporting standards of reasons may help to further estimate relative frequencies and thereby guide priorities for technical development and scientific effort.

Aspiration thrombectomy in clinical routine interventional stroke treatment : Is this the end of the stent retriever era?

PURPOSE: The aim of our study was the technical evaluation of a first pass approach of primary thrombus aspiration (AST) in patients with emergency large intracerebral vessel occlusions (ELVO) under routine clinical conditions. MATERIALS AND METHODS: We collected procedural and clinical data of 104 patients who underwent mechanical thrombectomy due to ELVO between June 2014 and January 2016 with intentional first-line thrombus aspiration. Procedures were conducted due to occlusions of the distal internal carotid artery, middle cerebral artery, anterior cerebral artery, basilar artery and posterior cerebral artery and were performed with the patient under either conscious sedation or general anesthesia. If the AST technique failed completely or to some extent, stent retriever-based thrombectomy (SRT) was performed. RESULTS: As a stand-alone method AST was successful in achieving TICI (Thrombolysis in Cerebral Infarction) score 2b or 3 results in 29 cases (27.8%). After additional use of SRT successful recanalization was achieved in a total of 95 cases (91.3%, p = 0.048). If AST was performed exclusively, median procedure time until TICI 2b/3 was 15 min, in cases of combined procedures 35 min (p = 0.001). Subarachnoid hemorrhage (SAH) after thrombectomy appeared only if additional SRT was performed (12.0%) and not in cases of AST maneuvers alone (p = 0.09). CONCLUSION: When used as a first pass attempt AST is a fast and safe approach for patients suffering from stroke due to ELVO. Nonetheless, early conversion to SRT is needed in most cases and leads to overall excellent procedural results with low complication rates.

Risk of Thrombus Fragmentation during Endovascular Stroke Treatment.

BACKGROUND AND PURPOSE: Periprocedural thrombus fragmentation is a relevant risk in endovascular stroke treatment. Because factors influencing its occurrence are largely unknown, this study addresses a potential relationship between thrombus histology and clot stability. MATERIALS AND METHODS: Eighty-five patients with anterior circulation stroke treated with thrombectomy were included in this retrospective study. The number and location of emboli after retrieving the primary thrombus, the number of maneuvers, and TICI scores were evaluated. H&E and neutrophil elastase staining of retrieved clots was performed, and semiquantitative measurements of thrombus components were correlated with procedural parameters. RESULTS: An inverse correlation between maneuvers required for thrombus retrieval and the number of distal and intermediate emboli was observed (Spearman r, -0.23; P = .032). Younger patients were at higher risk for periprocedural thrombus fragmentation (Spearman r, -0.23; P = .032). Bridging thrombolysis tended to be associated with fewer maneuvers (2 vs 3, P = .054) but more emboli (1 vs 0, P = .067). While no consistent correlation between procedural parameters and red/white blood cells and fibrin-/platelet fractions could be found, higher amounts of neutrophil elastase-positive cells within the thrombus were independently associated with the occurrence of multiple emboli (adjusted OR, 4.6; 95% CI, 1.1-19.7; P = .041) and lower rates of complete recanalization (adjusted OR, 0.3; 95% CI, 0.1-0.9; P = .050). CONCLUSIONS: Younger age, easy-to-retrieve thrombi, and bridging thrombolysis may be risk factors for periprocedural thrombus fragmentation. Findings from standard histologic stains did not provide insight into thrombectomy-relevant thrombus stability. However, higher neutrophil levels in the thrombus tissue were related to an increased risk of periprocedural thrombus fragmentation. This observation aligns with the proposed thrombolytic capacity of neutrophil elastase and points to its potential clinical relevance in the context of stroke thrombectomy.