Endovascular therapy in patients with internal carotid artery occlusion and patent circle of Willis.

BACKGROUND: Occlusion of the internal carotid artery (ICA) may extend into the middle or anterior cerebral artery (ICA-T) or be confined to the intracranial (ICA-I) or extracranial segment (ICA-E). While there is excellent evidence for endovascular therapy (EVT) in ICA-T occlusions, studies on EVT in non-tandem ICA-I or ICA-E occlusions are scarce. OBJECTIVE: To characterize EVT-treated patients with ICA-I- and ICA-E occlusion by comparing them with ICA-T occlusions. METHODS: The German Stroke Registry (GSR), a national, multicenter, prospective registry was searched for EVT-treated patients with isolated ICA occlusion between June 2015 and December 2021. We stratified patients by ICA occlusion site: (a) ICA-T, (b) ICA-I, (c) ICA-E. Baseline factors, procedural variables, technical (modified Thrombolysis in Cerebral Infarction (mTICI)), and functional outcomes (modified Rankin scale score at 3 months) were analyzed. RESULTS: Of 13 082 GSR patients, 2588 (19.8%) presented with an isolated ICA occlusion, thereof 1946 (75.2%) ICA-T, 366 (14.1%) ICA-I, and 276 (10.7%) ICA-E patients. The groups differed in age (77 vs 76 vs 74 years, Ptrend=0.02), sex (53.4 vs 48.9 vs 43.1% female, Ptrend<0.01), and stroke severity (median National Institutes of Health Stroke Scale score at admission 17 vs 14 vs 13 points, Ptrend<0.001). In comparison with ICA-T occlusions, both ICA-I and ICA-E occlusions had lower rates of successful recanalization (mTICI 2b/3: 85.4% vs 80.4% vs 76.3%; aOR (95% CI for ICA-I vs ICA-T 0.71 (0.53 to 0.95); aOR (95% CI) for ICA-E vs ICA-T 0.57 (0.42 to 0.78)). In adjusted analyses, ICA-E occlusion was associated with worse outcome when compared with ICA-T occlusion (mRS ordinal shift, cOR (95% CI) 0.70 (0.52 to 0.93)). CONCLUSION: Patient characteristics and outcomes differ substantially between ICA-T, ICA-I, and ICA-E occlusions. These results warrant further studies on EVT in ICA-I and ICA-E patients.

Decline of thrombolysis rates before endovascular therapy in patients with acute anterior circulation large vessel occlusion ischemic stroke: A multicenter analysis from the German Stroke Registry.

INTRODUCTION: In recent years, the role of intravenous thrombolysis (IVT) before endovascular stroke treatment (EVT) has been discussed intensively. Whether the discussion was accompanied by changing rates of bridging IVT is unknown. METHODS: Data were extracted from the prospectively maintained German Stroke Registry, including patients treated with EVT at one of 28 stroke centers in Germany between 2016 and 2021. Primary outcome parameters were the rate of bridging IVT (a) in the entire registry cohort and (b) in patients without formal contraindications to IVT (i.e. recent oral anticoagulants, time window ⩾4.5 h, extensive early ischemic changes) adjusted for demographic and clinical confounders. RESULTS: 10,162 patients (52.8% women, median age 77 years, median National Institutes of Health Stroke Scale score 14) were analyzed. In the entire cohort, the rate of bridging IVT decreased from 63.8% in 2016 to 43.6% in 2021 (average absolute annual decrease 3.1%, 95% CI 2.4%-3.8%), while the proportion of patients with at least one formal contraindication increased by only 1.2% annually (95% CI 0.6%-1.9%). Among 5460 patients without record of formal contraindications, the rate of bridging IVT decreased from 75.5% in 2016 to 63.2% in 2021 and was significantly associated with admission date in a multivariable model (average absolute annual decrease 1.4%, 95% CI 0.6%-2.2%). Clinical factors associated with lower odds of bridging IVT included diabetes mellitus, carotid-T-occlusion, dual antiplatelet therapy, and direct admission to a thrombectomy center. CONCLUSION: We observed a substantial decline in bridging IVT rates independent of demographic confounders and not explained by an increase in contraindications. This observation deserves further exploration in independent populations.

Delirium in older hospitalized patients-A prospective analysis of the detailed course of delirium in geriatric inpatients.

BACKGROUND: Delirium in older hospitalized patients (> 65) is a common clinical syndrome, which is frequently unrecognized. AIMS: We aimed to describe the detailed clinical course of delirium and related cognitive functioning in geriatric patients in a mainly non-postoperative setting in association with demographic and clinical parameters and additionally to identify risk factors for delirium in this common setting. METHODS: Inpatients of a geriatric ward were screened for delirium and in the case of presence of delirium included into the study. Patients received three assessments including Mini-Mental-Status-Examination (MMSE) and the Delirium Rating Scale Revised 98 (DRS-R-98). We conducted correlation and linear mixed-effects model analyses to detect associations. RESULTS: Overall 31 patients (82 years (mean)) met the criteria for delirium and were included in the prospective observational study. Within one week of treatment, mean delirium symptom severity fell below the predefined cut-off. While overall cognitive functioning improved over time, short- and long-term memory deficits remained. Neuroradiological conspicuities were associated with cognitive deficits, but not with delirium severity. DISCUSSION: The temporal stability of some delirium symptoms (short-/long-term memory, language) on the one hand and on the other hand decrease in others (hallucinations, orientation) shown in our study visualizes the heterogeneity of symptoms attributed to delirium and their different courses, which complicates the differentiation between delirium and a preexisting cognitive decline. The recovery from delirium seems to be independent of preclinical cognitive status. CONCLUSION: Treatment of the acute medical condition is associated with a fast decrease in delirium severity. Given the high incidence and prevalence of delirium in hospitalized older patients and its detrimental impact on cognition, abilities and personal independence further research needs to be done.

Thrombus migration in ischemic stroke due to large vessel occlusion: a question of time.

BACKGROUND: Thrombus migration (TM) is frequently observed in large vessel occlusion (LVO) ischemic stroke to be treated by endovascular thrombectomy (EVT). TM may impede complete recanalization and hereby worsen clinical outcomes. This study aimed to delineate factors associated with TM and clarify its impact on technical and functional outcome. METHODS: All patients undergoing EVT due to LVO in the anterior circulation at two tertiary stroke centers between October 2015 and December 2020 were included. Source imaging data of all individuals were assessed regarding occurrence of TM by raters blinded to clinical data. Patient data were gathered as part of the German Stroke Registry, a multicenter, prospective registry assessing real-world outcomes. Technical outcome was assessed by modified Thrombolysis in Cerebral Infarction scale (mTICI). Functional outcome was assessed by modified Rankin Scale (mRS) at 3 months. RESULTS: The study consisted of 512 individuals, of which 71 (13.8%) displayed TM. In adjusted analyses, TM was associated with longer time from primary imaging to reassessment in the angio suite (aOR 2.37 (1.47 to 3.84) per logarithmic step) and intravenous thrombolysis (IVT; aOR 4.07 (2.17 to 7.65)). In individuals with IVT, a needle-to-groin time >1 hour was associated with higher odds for TM (aOR 2.60 (1.20 to 5.99)). TM was associated with lack of complete recanalization (aORmTICI3 0.46 (0.24 to 0.90)) but TM did not worsen odds for good clinical outcome (aORmRS≤2_d90 0.89 (0.47 to 1.68)). CONCLUSIONS: TM is associated with IVT and longer time between sequential assessments of thrombus location. Consequently, TM may be of high relevance in patients with drip-and-ship treatment.

Mechanical thrombectomy of acute occlusions of individual distal anterior cerebral artery branches.

To describe our experience with mechanical thrombectomy (MT) in distal anterior cerebral artery (ACA) occlusions regarding recanalization rates, MT techniques and procedural safety. From a prospectively maintained thrombectomy database all patients with distal ACA occlusions treated with MT between April 2013 and February 2021 were retrospectively identified. Imaging data and angiographic features as well as clinical data were collected. 41 patients were included in the study, including 23 patients (56.1%) with distal main stem occlusions (occlusions distal to the anterior communicating artery but proximal to the origin of the pericallosal and callosomarginal arteries) and 18 patients (46.3%) with distal individual branch occlusions (occlusions of the pericallosal or callosomarginal arteries and their ramifications). A stent retriever mediated technique was applied in 34 patients (82.9%), the ADAPT technique in 7 patients (17.1%). Successful (mTICI 2b/3) and complete recanalization (mTICI 3) rates did not differ for the distal ACA main stem occlusion group (82.6%/56.5%), and the individual branch occlusion group (83.3%/55.6%) (p ≫ 0.05). No severe complications specific to distal MT maneuvers were noted. MT for acute distal individual ACA branch occlusions beyond the common A2/3 trunk appears safe and technically effective in different clinical settings and occlusion patterns with high recanalization rates. However, further studies are required to determine the clinical effectiveness.

Mechanical thrombectomy of acute distal posterior cerebral artery occlusions.

To describe our experience with mechanical thrombectomy (MTE) of acute distal posterior cerebral artery (PCA) occlusions, either isolated or in combination with more proximal vessel occlusions regarding recanalization rates, MTE techniques, and procedural safety. From the prospectively maintained stroke thrombectomy databases of two institutions, all consecutive patients subjected to MTE of acute distal PCA occlusion (P2 and 3 segments) between July 2013 and May 2020 were retrospectively identified. Imaging data and angiographic features, as well as patients' demographic and clinical data were evaluated. 35 consecutive patients were included in the study. In 17 patients MTE of isolated acute distal PCA occlusion was performed. 9 patients had combined basilar artery (BA) and distal PCA occlusion on stroke imaging and 3 had embolic distal PCA occlusion following MTE for BA occlusion. 6 patients harbored distal PCA occlusions in combination with carotid-T occlusion and a dominant posterior communicating artery. The median NIHSS at presentation was 14 (IQR 8 - 27). 25 patients (71.4%) had occlusions of the P2 and 10 patients (28.6%) of the P3 segment. Successful recanalization (TICI 2b/3) was achieved in 31 patients (88.6%). 10 patients (28.6%) were treated with a direct contact aspiration technique, while a stent retriever was used in 25 patients (71.4%). No complication attributable to distal PCA MTE occurred. Good outcome (mRS ≤ 2) was achieved in 14 patients (46.7%) and mortality was 22.9%. MTE for acute distal PCA occlusion in the setting of different occlusion patterns appears both safe and angiographically effective. Yet, clinical effectiveness remains to be determined.

Early Thrombectomy Protects the Internal Capsule in Patients With Proximal Middle Cerebral Artery Occlusion.

BACKGROUND AND PURPOSE: Proximal middle cerebral artery (MCA) occlusions impede blood flow to the noncollateralized lenticulostriate artery territory. Previous work has shown that this almost inevitably leads to infarction of the dependent gray matter territories in the striate even if perfusion is restored by mechanical thrombectomy. Purpose of this analysis was to evaluate potential sparing of neighboring fiber tracts, ie, the internal capsule. METHODS: An observational single-center study of patients with proximal MCA occlusions treated with mechanical thrombectomy and receiving postinterventional high-resolution diffusion-weighted imaging was conducted. Patients were classified according to internal capsule ischemia (IC+ versus IC-) at the postero-superior level of the MCA lenticulostriate artery territory (corticospinal tract correlate). Associations of IC+ versus IC- with baseline variables as well as its clinical impact were evaluated using multivariable logistic or linear regression analyses adjusting for potential confounders. RESULTS: Of 92 included patients with proximal MCA territory infarctions, 45 (48.9%) had an IC+ pattern. Longer time from symptom-onset to groin-puncture (adjusted odds ratio, 2.12 [95% CI, 1.19-3.76] per hour), female sex and more severe strokes were associated with IC+. Patients with IC+ had lower rates of substantial neurological improvement and functional independence (adjusted odds ratio, 0.26 [95% CI, 0.09-0.81] and adjusted odds ratio, 0.25 [95% CI, 0.07-0.86]) after adjustment for confounders. These associations remained unchanged when confining analyses to patients without ischemia in the corona radiata or the motor cortex and here, IC+ was associated with higher National Institutes of Health Stroke Scale motor item scores (ß, +2.8 [95% CI, 1.5 to 4.1]) without a significant increase in nonmotor items (ß, +0.8 [95% CI, -0.2 to 1.9). CONCLUSIONS: Rapid mechanical thrombectomy with successful reperfusion of the lenticulostriate arteries often protects the internal capsule from subsequent ischemia despite early basal ganglia damage. Salvage of this eloquent white matter tract within the MCA lenticulostriate artery territory seems strongly time-dependent, which has clinical and pathophysiological implications.

Direct puncture of the carotid artery as a bailout vascular access technique for mechanical thrombectomy in acute ischemic stroke-the revival of an old technique in a modern setting.

PURPOSE: To describe our single-center experience of mechanical thrombectomy (MTE) via a direct carotid puncture (DCP) with regard to indication, time metrics, procedural details, as well as safety and efficacy aspects. METHODS: DCP thrombectomy cases performed at our center were retrospectively identified from a prospectively maintained institutional MTE database. Various patient (age, sex, stroke cause, comorbidities), clinical (NIHSS, mRS), imaging (occlusion site, ASPECT score), procedural (indication for DCP, time from DCP to reperfusion, materials used, technical nuances), and outcome data (NIHSS, mRS) were tabulated. RESULTS: Among 715 anterior circulation MTEs, 12 DCP-MTEs were identified and analyzed. Nine were left-sided M1 occlusions, one right-sided M1 occlusion, and two right-sided M2 occlusions. DCP was successfully carried out in 91.7%; TICI 2b/3-recanalization was achieved in 83.3% via direct lesional aspiration and/or stent-retrieval techniques. Median time from DCP to reperfusion was 23 min. Indications included futile transfemoral catheterization attempts of the cervical target vessels as well as iliac occlusive disease. Neck hematoma occurred in 2 patients, none of which required further therapy. CONCLUSION: MTE via DCP in these highly selected patients was reasonably safe, fast, and efficient. It thus represents a valuable technical extension of MTE, especially in patients with difficult access.

Direct mechanical thrombectomy in tPA-ineligible and -eligible patients versus the bridging approach: a meta-analysis.

BACKGROUND: Whether pretreatment with intravenous thrombolysis prior to mechanical thrombectomy (IVT+MTE) adds additional benefit over direct mechanical thrombectomy (dMTE) in patients with large vessel occlusions (LVO) is a matter of debate. METHODS: This study-level meta-analysis was presented in accord with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled effect sizes were calculated using the inverse variance heterogeneity model and displayed as summary Odds Ratio (sOR) and corresponding 95% confidence interval (95% CI). Sensitivity analysis was performed by distinguishing between studies including dMTE patients eligible for IVT (IVT-E) or ineligible for IVT (IVT-IN). Primary outcome measures were functional independence (modified Rankin Scale≤2) and mortality at day 90, successful reperfusion, and symptomatic intracerebral hemorrhage. RESULTS: Twenty studies, incorporating 5279 patients, were included. There was no evidence that rates of successful reperfusion differed in dMTE and IVT+MTE patients (sOR 0.93, 95% CI 0.68 to 1.28). In studies including IVT-IN dMTE patients, patients undergoing dMTE tended to have lower rates of functional independence and had higher odds for a fatal outcome as compared with IVT+MTE patients (sOR 0.78, 95% CI 0.61 to 1.01 and sOR 1.45, 95% CI 1.22 to 1.73). However, no such treatment group effect was found when analyses were confined to cohorts with a lower risk of selection bias (including IVT-E dMTE patients). CONCLUSION: The quality of evidence regarding the relative merits of IVT+MTE versus dMTE is low. When considering studies with lower selection bias, the data suggest that dMTE may offer comparable safety and efficacy as compared with IVT+MTE. The conduct of randomized-controlled clinical trials seems justified.

Detecting optic nerve lesions in clinically isolated syndrome and multiple sclerosis: double-inversion recovery magnetic resonance imaging in comparison with visually evoked potentials.

BACKGROUND AND AIM: Optic neuritis (ON) is a frequent manifestation of multiple sclerosis (MS), traditionally diagnosed clinically and by visually evoked potentials (VEP). However, ON can also be assessed by MRI. Here we compare the diagnostic performance of 3D-double inversion recovery-MRI (3D-DIR) and VEPs in patients with definite MS or clinically isolated syndrome (CIS). METHODS: 39 patients and 17 healthy controls were studied. Whole-brain-3D-DIR images (3T) were independently assessed for DIR-hyperintense optic nerve lesions (DHLs) by two neuroradiologists, and results related to quantitative VEP-parameters. RESULTS: Interrater concordance for DHLs was high (κ = 0.82). No DHLs were observed in controls. In patients, abnormal VEPs, i.e. prolonged latencies, diminished amplitudes or abnormal latency or amplitude differences (re contralateral nerve) of the P100-component, were observed in 22, and DHLs in 32 of 78 optic nerves, the latter including 11 nerves with normal VEPs, 10 without clinical signs or history of ON, and 6 with both normal VEPs and no clinical evidence for ON. Using either abnormal VEPs and/or presence of DHLs and/or clinical evidence for ON as a compound reference criterion of optic nerve affection, sensitivity was significantly higher for 3D-DIR than for VEPs (91%, 95%-CI 77-98% vs. 63%, 95%-CI 45-79%, respectively, p = 0.006). CONCLUSION: DHLs are highly specific for optic nerve pathology. In the context of MS, 3D-DIR-MRI is a suitable tool to reveal acute or chronic optic nerve lesions and more sensitive than VEPs. The significance of optic nerve involvement in the diagnostic classification of CIS vs. definite MS requires further study.

Impact of time to endovascular reperfusion on outcome differs according to the involvement of the proximal MCA territory.

BACKGROUND: The time interval between symptom onset and reperfusion is a major determinant of the benefit of endovascular therapy (ET) and patients' outcome. The impact of time may be attenuated in patients with robust collaterals. However, not all regions in the middle cerebral artery (MCA) territory have access to collaterals. PURPOSE: To evaluate if the involvement of the poorly collateralized proximal MCA territory has an impact on the degree of time dependency of patients' outcome. METHODS: Patients with MCA occlusions treated with ET and involvement/sparing of the proximal striatocapsular MCA territory (SC+/SC-, each n=97) were matched according to their symptom onset to reperfusion times (SORTs). Correlation and impact of time on outcome was evaluated with strata of SC+/SC- using multivariate logistic regression models (LRMs), including interaction terms. Discharge National Institute of Health Stroke Scale (NIHSS-DIS) score <5 and discharge modified Rankin Scale (mRS-DIS) score ≤2 were prespecified outcome measures. RESULTS: A stronger correlation between all outcome measures (NIHSS-DIS/ΔNIHSS/mRS-DIS) and SORTs was found for SC+ patients than for SC-patients. SORTs were significant variables in LRMs for mRS-DIS score ≤2 and NIHSS-DIS score <5 in SC+ but not in SC- patients. Interaction of SC+ and SORTs was significant in LRMs for both endpoints. CONCLUSION: Time dependency of outcome after ET is more pronounced if parts of the proximal MCA territory are affected. This may reflect the lack of collateralization in the striatocapsular region and a more stringent cell death with time. If confirmed, this finding may affect the selection of patients based on different time windows according to the territory at risk.

Bridging Therapy with i. v. rtPA in MCA Occlusion Prior to Endovascular Thrombectomy: a Double-Edged Sword?

BACKGROUND: Recent studies suggested that preinterventional intravenous (i. v.) recombinant tissue plasminogen activator (rtPA) as bridging therapy facilitates successful and fast vessel recanalization in endovascular stroke treatment (EST); however, data on this effect and the associated clinical value are discrepant. OBJECTIVE: This study examined if this discrepancy could be related to an effect-modifying variable, specifically to the exact occlusion site. METHODS: Retrospective analysis of 239 patients with acute occlusion of the middle cerebral artery (MCA) treated with up to date endovascular techniques. Effects of i. v.-rtPA bridging on clinical outcomes and safety/efficacy of EST, defined as the respective rates of successful, first pass and thrombolysis in cerebral infarction (TICI) scale 3 recanalization, were evaluated and stratified according to distal versus proximal occlusion sites. RESULTS: Overall, i. v.-rtPA bridging was associated with a significantly higher rate of successful recanalization (86.9 % vs. 75.7 %, p = 0.028). i. v.-rtPA bridging-related effects, however, were observable only in distal, but not in proximal MCA-occlusions. In distal occlusions, i. v.-rtPA clearly favored successful recanalization (adj. OR 4.6, 95 %-CI 1.5-13.6, p = 0.006) and first-pass successes (adj. OR 2.8, 95 %-CI 1.0-7.6, p = 0.042), but tended to be associated with lower rates of complete (TICI-3) reperfusion (adj. OR 0.4, 95 %-CI 0.2-1.1, p = 0.068). The net effect was a small clinical benefit, reflected in higher rates of strong neurological improvement (adj. OR: 2.8, 95 %-CI: 1.1-6.9, p = 0.03). CONCLUSION: i. v.-rtPA-bridging-related effects are occlusion site-dependent, paralleling similar effects of systemic i. v.-rtPA when applied without subsequent endovascular therapy. In distal occlusions, i. v.-rtPA facilitates thrombectomy, but may also promote distal embolization, with a small clinical benefit as overall net effect. Randomized trials assessing i.v-rtPA bridging need to be stratified according to occlusions sites.

Clinical outcome prediction after thrombectomy of proximal middle cerebral artery occlusions by the appearance of lenticulostriate arteries on magnetic resonance angiography: A retrospective analysis.

Post-ischemic vasodynamic changes in infarcted brain parenchyma are common and range from hypo- to hyperperfusion. In the present study, appearance of the lenticulostriate arteries (LSAs) on postinterventional 3T time-of-flight (TOF)-MRA suggestive for altered post-stroke vasodynamics following thrombectomy was investigated. Patients who underwent thrombectomy for a proximal MCA occlusion and for whom postinterventional 3T TOF-MRA (median at day 3) was available, were included in this retrospective analysis (n=98). LSA appearance was categorized into presence (LSA-sign+) or absence (LSA-sign-) of vasodilatation in the ischemic hemisphere. Functional outcome was determined using the modified Rankin scale (mRS). LSA-sign+ was observed in 64/98 patients. Hypertension (adjusted OR: 0.171, 95% CI: 0.046-0.645) and preinterventional IV rtPA (adjusted OR: 0.265, 95% CI: 0.088-0.798) were associated with absence of the LSA-sign+. In multivariate logistic regression, LSA-sign+ was associated with substantial neurologic improvement (adjusted OR: 10.18, 95% CI: 2.69-38.57) and good functional outcome (discharge-mRS ≤ 2, adjusted OR: 7.127, 95% CI: 1.913-26.551 and day 90 mRS ≤ 2, adjusted OR: 3.786, 95% CI: 1.026-13.973) after correcting for relevant confounders. For all clinical endpoints, model fit improved when including the LSA-sign term (p<0.05). Asymmetrical dilatation of LSAs following successful thrombectomy indicates favorable neurologic and mid-term functional outcomes. This may indicate preserved cerebral blood flow regulatory mechanisms.

Tissue-Selective Salvage of the White Matter by Successful Endovascular Stroke Therapy.

BACKGROUND AND PURPOSE: White matter (WM) is less vulnerable to ischemia than gray matter. In ischemic stroke caused by acute large-vessel occlusion, successful recanalization might therefore sometimes selectively salvage the WM, leading to infarct patterns confined to gray matter. This study examines occurrence, determinants, and clinical significance of such effects. METHODS: Three hundred twenty-two patients with acute middle cerebral artery occlusion subjected to mechanical thrombectomy were included. Infarct patterns were categorized into WM- (sparing the WM) and WM+ (involving WM). National Institutes of Health Stroke Scale-based measures of neurological outcome, including National Institutes of Health Stroke Scale improvement or National Institutes of Health Stroke Scale worsening, good functional midterm outcome (day 90-modified Rankin Scale score of ≤2), the occurrence of malignant swelling, and in-hospital mortality were predefined outcome measures. RESULTS: WM- infarcts occurred in 118 of 322 patients and were associated with successful recanalization and better collateral grades (P<0.05). Shorter symptom-onset to recanalization times were also associated with WM- infarcts in univariate analysis, but not when adjusted for collateral grades. WM- infarcts were independently associated with good neurological outcome (adjusted odds ratio, 3.003; 95% confidence interval, 1.186-7.607; P=0.020) and good functional midterm outcome (adjusted odds ratio, 8.618; 95% confidence interval, 2.409-30.828; P=0.001) after correcting for potential confounders, including final infarct volume. Only 2.6% of WM- patients, but 20.5% of WM+ patients exhibited neurological worsening, and none versus 12.8% developed malignant swelling (P<0.001), contributing to lower mortality in this group (2.5% versus 10.3%; P=0.014). CONCLUSIONS: WM infarction commonly commences later than gray matter infarction after acute middle cerebral artery occlusion. Successful recanalization can therefore salvage completely the WM at risk in many patients even several hours after symptom onset. Preservation of the WM is associated with better neurological recovery, prevention of malignant swelling, and reduced mortality. This has important implications for neuroprotective strategies, and perfusion imaging-based patient selection, and provides a rationale for treating selected patients in extended time windows.

Isolated Striatocapsular Infarcts after Endovascular Treatment of Acute Proximal Middle Cerebral Artery Occlusions: Prevalence, Enabling Factors, and Clinical Outcome.

BACKGROUND: Striatocapsular infarcts (SCIs) are defined as large subcortical infarcts involving the territory of more than one lenticulostriate artery. SCI without concomitant ischemia in the more distal middle cerebral artery (MCA) territory [isolated SCI (iSCI)] has been described as a rare infarct pattern. The purpose of this study was to assess the prevalence of iSCI in patients treated with endovascular thrombectomy (ET), to evaluate baseline and procedural parameters associated with this condition, and to describe the clinical course of iSCI patients. METHODS: A retrospective analysis of 206 consecutive patients with an isolated MCA occlusion involving the lenticulostriate arteries and treated with ET was performed. Baseline patient and procedural characteristics and ischemic involvement of the striatocapsular and distal MCA territory [iSCI, as opposed to non-isolated SCI (niSCI)] were analyzed using multivariate logistic regression models. Prevalence of iSCI was assessed, and clinical course was determined with the rates of substantial neurological improvement and good functional short- and mid-term outcome (discharge/day 90 Modified Rankin Scale ≤2). RESULTS: iSCI was detected in 53 patients (25.7%), and niSCI was detected in 153 patients (74.3%). Successful reperfusion [thrombolysis in cerebral infarction (TICI) 2b/3] [adjusted odds ration (aOR) 8.730, 95% confidence interval (95% CI) 1.069-71.308] and good collaterals (aOR 2.100, 95% CI 1.119-3.944) were associated with iSCI. In successfully reperfused patients, TICI 3 was found to be an additional factor associated with iSCI (aOR 5.282, 1.759-15.859). Patients with iSCI had higher rates of substantial neurological improvement (71.7 vs. 37.9%, p < 0.001) and higher rates of good functional short- and mid-term outcome (58.3 vs. 23.7%, p < 0.001 and 71.4 vs. 41.7%, p < 0.001). However, while iSCI patients, in general, had a more favorable outcome, considerable heterogeneity in outcome was observed. CONCLUSION: High rates of successful reperfusion (TICI 2b/3) and in particular, complete reperfusion (TICI 3) are associated with iSCIs. The high prevalence of iSCI in successfully reperfused patients with good collaterals corroborates previous concepts of iSCI pathogenesis. iSCI, once considered a rare pattern of cerebral ischemia, is likely to become more prevalent with increases in endovascular stroke therapy. This may have implications for patient rehabilitation and pathophysiological analyses of ischemic damage confined to subcortical regions of the MCA territory.

Hemorrhagic Transformations after Thrombectomy: Risk Factors and Clinical Relevance.

BACKGROUND: Hemorrhagic transformation (HT) is a major complication of acute ischemic stroke, potentially associated with clinical deterioration. We attempted to identify risk factors and evaluated clinical relevance of minor and major HTs following endovascular thrombectomy (ET) in isolated middle cerebral artery (MCA) occlusions. METHODS: This is a retrospective single-center analysis of 409 patients with isolated MCA occlusion treated with ET. Patients' and procedural characteristics, severity of HT according to the European Cooperative Acute Stroke Study criteria, and clinical outcomes were analyzed. Multivariate logistic regression models with standard retention criteria (p < 0.1) were used to determine risk factors and clinical relevance of HT. Results are shown as adjusted OR (aOR) and respective 95% CIs. Good neurologic short-term outcome was defined as National Institutes of Health Stroke Scale (NIHSS) score <5 at the day of discharge. RESULTS: Of 299 patients included, hemorrhagic infarction (HI) was detected in 87 patients, while 13 patients developed parenchymal hematoma (PH). Higher age (aOR 0.970, 95% CI 0.947-0.993, p = 0.012), eligibility for intravenous recombinant tissue plasminogen activator (IV rtPA; aOR 0.512, 95% CI 0.267-0.982, p = 0.044), and complete recanalization (TICI 3, aOR 0.408, 95% CI 0.210-0.789, p = 0.008) were associated with a lower risk of HI. Risk factors for HI included higher admission NIHSS score (aOR 1.080, 95% CI 1.010-1.153, p = 0.024) and higher admission glucose levels (aOR 1.493, 95% CI 1.170-1.904, p = 0.001). Further, female sex tended to be associated with a lower risk of HI (aOR 0.601, 95% CI 0.316-1.143, p = 0.121), while a statistical trend was observable for proximal MCA occlusion (aOR 1.856, 95% CI 0.945-3.646, p = 0.073) and a history of hypertension (aOR 2.176, 95% CI 0.932-5.080, p = 0.072) to increase risk of HI. Longer intervals from symptom onset to first digital subtraction angiography runs (aOR 1.013, 95% CI 1.003-1.022, p = 0.009), lower preinterventional Alberta Stroke Program Early CT score (aOR 0.536, 95% CI 0.307-0.936, p = 0.028) and wake-up stroke (aOR 18.540, 95% CI 1.352-254.276, p = 0.029) were associated with PH. Both, PH and HI were independently associated with lower rates of good neurologic outcome (aOR 0.086, 95% CI 0.008-0.902, p = 0.041 and aOR 0.282, 95% CI 0.131-0.606, p = 0.001). CONCLUSION: Risk of HI following MCA occlusion and subsequent ET is mainly determined by factors influencing infarct severity. Good recanalization results seem to be protective against subsequent HI. Our results support the notion that occurrence of PH after ET is time dependent and risk increases with more extensive early ischemic damage. Both, HI and PH do not seem to be facilitated by bridging therapy with IV rtPA or the use of oral anticoagulants, but were independently associated with more severe neurologic disability. These results support the notion that HI is not a "benign" imaging sign.

Thrombus Migration in the Middle Cerebral Artery: Incidence, Imaging Signs, and Impact on Success of Endovascular Thrombectomy.

BACKGROUND: Thrombus migration (TM) in intracranial vessels during ischemic stroke has been reported in the form of case reports, but its incidence, impact on the technical success of subsequent endovascular thrombectomy and patients' outcome have never been studied systematically. METHODS AND RESULTS: Retrospective analysis was done of 409 patients with isolated middle cerebral artery occlusions treated with endovascular thrombectomy. TM was observed (1) by analyzing discrepancies between computed tomographic angiography and digital subtraction angiography and (2) by comparing infarct pattern in the striatocapsular region with exact, angiographically assessed thrombus location within the M1-segment and the involvement of the middle cerebral artery perforators. Preinterventional infarction of discrepant regions (infarction in regions supplied by more proximal vessels than those occluded by the clot) was ensured by carefully reviewing available preinterventional multimodal imaging. Adequate imaging inclusion criteria were met by 325 patients. Ninety-seven patients showed signs of TM (26 with direct evidence, 71 with indirect evidence). There was no difference in the frequency of preinterventional intravenous recombinant tissue plasminogen activator administration between patients with TM and those without (63.9% vs 64.9%, P=0.899). TM was associated with lower rates of complete reperfusion (Thrombolysis in Cerebral Infarction score 3) (adjusted odds ratio 0.400, 95% CI 0.226-0.707). Subsequently, preinterventional TM was associated with lower rates of substantial neurologic improvement (adjusted odds ratio 0.541, 95% CI 0.309-0.946). CONCLUSIONS: Preinterventional TM does not seem to be facilitated by intravenous recombinant tissue plasminogen activator and often occurs spontaneously. However, TM is associated with the risk of incomplete reperfusion in subsequent thrombectomy, suggesting increased clot fragility. Occurrence of TM may thereby have a substantial impact on the outcome of endovascularly treated stroke patients.

Lenticulostriate infarctions after successful mechanical thrombectomy in middle cerebral artery occlusion.

BACKGROUND: In stroke due to middle cerebral artery (MCA) occlusion, collaterals may sustain tissue in the peripheral MCA territory, extending the time window for recanalizing therapies. However, MCA occlusions often block some or all of the 'lenticulostriate' (LS) arteries originating from the M1 segment, eliminating blood flow to dependent territories in the striatum, which have no collateral supply. This study examines whether mechanical thrombectomy (MTE) can avert imminent striatal infarction in patients with acute MCA occlusion. METHODS: 279 patients with isolated MCA occlusion subjected to MTE were included. Actual LS occlusions and infarctions were assigned to predefined 'LS occlusion' and 'LS infarct' patterns derived from known LS vascular anatomy. The predictive performance of LS occlusion patterns regarding ensuing infarction in striatal subterritories was assessed by standard statistical measures. RESULTS: LS occlusion patterns predicted infarction in associated striatal subterritories with a positive predictive value (PPV) of 91% and a negative predictive value of 81%. In 15 of the 22 patients who did not develop the predicted striatal infarctions, reassessment of angiographies revealed LS vascular supply variants that explained these 'false positive' LS occlusion patterns, raising the PPV to 96%. Symptom onset to recanalization times were relatively short, but this alone could not account for the false positive LS occlusion patterns in the remaining seven of these patients. CONCLUSIONS: With currently achievable symptom onset to recanalization times, striatal infarctions are determined by MCA occlusion sites and individual vascular anatomy, and cannot normally be averted by MTE, but there are exceptions. Further study of such exceptional cases may yield important insights into the determinants of infarct growth in the hyperacute phase of infarct evolution.

Time to redefine success? TICI 3 versus TICI 2b recanalization in middle cerebral artery occlusion treated with thrombectomy.

BACKGROUND: The Thrombolysis in Cerebral Infarction (TICI) scale is the most widely applied scoring system to grade technical results of recanalizing therapies in acute ischemic stroke (AIS). TICI 2b and TICI 3 are conventionally subsumed as 'successful recanalization'. Previous studies reported conflicting results for the clinical relevance of achieving complete (TICI 3) versus 'almost' complete reperfusion (TICI 2b). OBJECTIVE: To examine if neurologic outcome differs significantly between TICI 2b and TICI 3 in patients with AIS with middle cerebral artery (MCA) occlusion treated 'successfully' with mechanical thrombectomy (MTE). METHODS: Retrospective analysis of prospectively collected data from 352 consecutive patients with isolated MCA occlusion subjected to MTE between January 2007 and July 2015. RESULTS: 262 of the 277 successfully treated patients had adequate follow-up and were included. Patients (n=119) in the TICI 3 group had a lower National Institutes of Health Stroke Scale score at discharge (NIHSS-DIS; median 5 vs 7, p=0.005), and showed higher rates of strong neurologic improvement (ΔNIHSS≥8 or NIHSS-DIS≤1, 68.4% vs 37.1%, p=0.002) and favorable NIHSS outcome (NIHSS-DIS≤5, 49.2% vs 31.9%, p=0.005). Hospital stays were shorter in the TICI 3 group (median 10 vs 12 days, p=0.014). After adjusting for relevant baseline and treatment parameters, TICI 3 was independently associated with strong neurologic improvement (OR=4.3, 95% CI 2.2 to 8.3, p<0.001) and favorable NIHSS outcome (OR=3.0, 95% CI 1.5 to 6.3, p=0.003). CONCLUSIONS: Neurologic outcome is substantially better in TICI 3 than TICI 2b patients, and hospital stays are shorter. Endovascular strategies that consequently strive to achieve TICI 3 may be warranted and cost-effective, and should be examined by future research. TICI 3 rates should be included as a safety measure in studies evaluating MTE devices and techniques.