Leticia C. Rebello

Optimizating Clot Retrieval in Acute Stroke The Push and Fluff Technique for Closed-Cell Stentrievers

Background and Purpose— We aimed to investigate the safety and efficacy of the Push and Fluff technique (PFT) as compared with the standard unsheathing technique for closed-cell stent retrievers in acute ischemic stroke. Methods— Acute ischemic stroke thrombectomy database was analyzed (September 2010 to January 2015) with the Trevo Retriever as a primary strategy. The PFT was compared with our internal standard unsheathing technique and with the Trevo Versus Merci Retrievers for Thrombectomy Revascularization of Large Vessel Occlusions in Acute Ischemic Stroke 2 (TREVO2) trial. Additionally, a silicon flow model was used to compare cell size/configuration, wall apposition/device diameter, and degree of foreshortening/device length across the 2 techniques. Results— One hundred fifty-one out of 662 patients qualified for the study. The PFT (n=71) was associated with higher rates of first-pass reperfusion (54% versus 35%, P=0.03; 54% versus 32.6%, P<0.01), lower number of passes (1.3±0.8 versus 1.8±1.0, P<0.01; 1.7±1.0 versus 2.4±1.6, P<0.01), and higher rates of modified treatment in cerebral ischemia-3 reperfusion (58% versus 40%, P=0.03; 58% versus 14%, P<0.01) as compared with the standard unsheathing technique (n=81) and the TREVO2 Trevo arm (n=88), respectively. No differences in hemorrhagic complications were observed across the groups. The in vitro model indicated that, compared with standard unsheathing technique, PFT resulted in improved wall apposition (device diameter, 75% larger) and cell size (mean area, 51% larger) at the cost of a mild degree of foreshortening (25% length reduction). Conclusions— The PFT is safe and leads to optimization of wall apposition and cell size/configuration, resulting in higher chances of first-pass reperfusion, lower number of passes, and better rates of complete reperfusion.

Too good to intervene? Thrombectomy for large vessel occlusion strokes with minimal symptoms: an intention-to-treat analysis

Introduction The minimal stroke severity justifying endovascular intervention remains elusive; however, a significant proportion of patients presenting with large vessel occlusion (LVO) and mild symptoms subsequently decline and face poor outcomes. Objective To evaluate our experience with these patients by comparing best medical therapy with thrombectomy in an intention-to-treat analysis. Methods Analysis of prospectively collected data of all consecutive patients with National Institutes of Health Stroke Scale (NIHSS) score ≤5, LVO on CT angiography, and baseline modified Rankin Scale (mRS) score 0–2 from November 2014 to May 2016. After careful discussion with patients/family, a decision to pursue medical or interventional therapy was made. Deterioration (development of aphasia, neglect, and/or significant weakness) triggered reconsideration of thrombectomy. The primary outcome measure was NIHSS shift (discharge NIHSS score minus admission NIHSS score). Results Of the 32 patients qualifying for the study, 22 (69%) were primarily treated with medical therapy and 10 (31%) intervention. Baseline characteristics were comparable. Nine (41%) medically treated patients had subsequent deterioration requiring thrombectomy. Median time from arrival to deterioration was 5.2 hours (2.0–25.0). Successful reperfusion (modified Treatment in Cerebral Infarction 2b−3) was achieved in all 19 thrombectomy patients. The NIHSS shift significantly favored thrombectomy (−2.5 vs 0; p<0.01). The median NIHSS score at discharge was low with both thrombectomy (1 (0–3)) and medical therapy (2 (0.5–4.5)). 90-Day mRS 0–2 rates were 100% and 77%, respectively (p=0.15). Multivariable linear regression indicated that thrombectomy was independently associated with a beneficial NIHSS shift (unstandardized β −4.2 (95% CI −8.2 to −0.1); p=0.04). Conclusions Thrombectomy led to a shift towards a lower NIHSS in patients with LVO presenting with minimal stroke symptoms. Despite the overall perception that this condition is benign, nearly a quarter of patients primarily treated with medical therapy did not achieve independence at 90 days.

Endovascular Treatment of Acute Ischemic Stroke Due to Tandem Occlusions: Large Multicenter Series and Systematic Review.

Background: Ischemic strokes due to tandem occlusions (TOs) have poor outcomes if they have been treated with only medical interventions. Recent trials demonstrated the effectiveness of endovascular treatment of acute ischemic stroke due to intracranial occlusions; however, most studies excluded patients with TOs. Methods: Retrospective review of prospectively collected thrombectomy databases from 3 stroke centers between 2011 and 2015. Consecutive patients with tandem extracranial steno-occlusive carotid disease and intracranial occlusions who underwent emergent thrombectomy were selected. Angiographic and clinical outcomes were analyzed; baseline and procedural variables were included in univariate and multivariate analyses to define the independent predictors of good outcomes (90-day modified Rankin Scale ≤2). Results: A total of 100 patients met the study inclusion criteria. The mean age was 64.4 ± 12.5, baseline National Institutes of Health Stroke Scale (NIHSS) 17.6 ± 5.0, time from last known well to puncture 7.3 ± 5.8 h, and Alberta Stroke Program Early CT Score (ASPECTS) 7.5 ± 1.6. Forty percent received intravenous tissue plasminogen activator. Intracranial occlusion sites included: internal carotid artery thrombus, 31%; middle cerebral artery (MCA)-M1, 53%; MCA-M2, 10%; and anterior cerebral artery, 6%. Good outcome was achieved in 42% and successful reperfusion modified thrombolysis in cerebral infarction (mTICI ≥2B) in 88% of the cases, including complete (mTICI 3) reperfusion in 40%. Severe parenchymal hematoma (PH)-2 occurred in 6% of the patients and 90-day mortality was 20%. In the multivariate analysis, younger age (OR 0.93; 95% CI 0.88-0.98; p = 0.004), lower baseline NIHSS (OR 0.84; 95% CI 0.74-0.94; p = 0.003), higher ASPECTS (OR 1.50; 95% CI 1.02-2.19; p = 0.038), and mTICI 3 reperfusion (OR 3.56; 95% CI 1.18-10.76; p = 0.024) were independent predictors of good outcome at 90 days. Conclusions: Acute endovascular treatment of tandem anterior circulation occlusions yields good outcomes and has similar outcome predictors to isolated intracranial occlusions. Given their comparable clinical behavior, these patients should be included in future trials.

Endovascular Treatment for Acute Ischemic Stroke in the Setting of Anticoagulation

Background and Purpose— Oral anticoagulation (OAC) plays a major role in atrial fibrillation stroke prevention but represents a contraindication to intravenous tissue-type plasminogen activator. Intra-arterial therapy remains a potential reperfusion strategy in these patients; however, supporting data are scarce. Methods— Retrospective analysis of prospectively collected consecutive intra-arterial therapies from October 2010 to March 2015 comparing OAC (vitamin-K antagonists and novel oral anticoagulants) versus normal hemostasis versus intravenous tissue-type plasminogen activator patients. Primary safety end point is parenchymal hematoma. Secondary safety end point is 90-day mortality. Efficacy end points are successful reperfusion (modified Thrombolysis in Cerebral Infarction, 2b-3) and good outcome (90-day modified Rankin Scale score of 0–2). Logistic regression for predictors of parenchymal hematoma was performed. Results— A total of 604 patients were qualified for the study. Baseline and outcomes variables were overall similar for vitamin-K antagonists (n=29) and novel oral anticoagulants (n=17) patients. When compared with normal hemostasis (n=265) and intravenous tissue-type plasminogen activator (n=297), OAC (n=46) patients were older and had more comorbidities. There were no statistically significant differences in the rates of parenchymal hematoma (8% versus 5%; P=0.42), 90-day modified Rankin Scale score of 0 to 2 (30% versus 40%; P=0.26), and 90-day mortality (32% versus 26%; P=0.46) among OAC and normal hemostasis patients. Similarly, there were no significant differences between OAC and intravenous tissue-type plasminogen activator patients in terms of parenchymal hematoma (8% versus 4%; P=0.16), 90-day modified Rankin Scale score of 0 to 2 (30% versus 43%; P=0.13), and 90-day mortality (32% versus 22%; P=0.18). The use of OAC was not associated with the occurrence of parenchymal hematoma on multivariate logistic regression analysis. Conclusions— Intra-arterial therapy seems to be safe in patients taking OACs; however, our study showed a nonsignificant increase in hemorrhage and mortality with a nonsignificant decrease in good outcomes in comparison with non-OAC patients. Although these nominal differences may have been related to older age and more comorbidities in the OAC group, larger studies are needed to confirm our findings given our limited sample size.

Endovascular Treatment for Patients With Acute Stroke Who Have a Large Ischemic Core and Large Mismatch Imaging Profile

Importance Endovascular therapy (ET) is typically not considered for patients with large baseline ischemic cores (irreversibly injured tissue). Computed tomographic perfusion (CTP) imaging may identify a subset of patients with large ischemic cores who remain at risk for significant infarct expansion and thus could still benefit from reperfusion to reduce their degree of disability. Objective To compare the outcomes of patients with large baseline ischemic cores on CTP undergoing ET with the outcomes of matched controls who had medical care alone. Design, Setting, and Participants A matched case-control study of patients with proximal occlusion after stroke (intracranial internal carotid artery and/or middle cerebral artery M1 and/or M2) on computed tomographic angiography and baseline ischemic core greater than 50 mL on CTP at a tertiary care center from May 1, 2011, through October 31, 2015. Patients receiving ET and controls receiving medical treatment alone were matched for age, baseline ischemic core volume on CTP, and glucose levels. Baseline characteristics and outcomes were compared. Main Outcomes and Measures The primary outcome measure was the shift in the degree of disability among the treatment and control groups as measured by the modified Rankin Scale (mRS) (with scores ranging from 0 [fully independent] to 6 [dead]) at 90 days. Results Fifty-six patients were matched across 2 equally distributed groups (mean [SD] age, 62.25 [13.92] years for cases and 58.32 [14.79] years for controls; male, 13 cases [46%] and 14 controls [50%]). Endovascular therapy was significantly associated with a favorable shift in the overall distribution of 90-day mRS scores (odds ratio, 2.56; 95% CI, 2.50-8.47; P = .04), higher rates of independent outcomes (90-day mRS scores of 0-2, 25% vs 0%; P = .04), and smaller final infarct volumes (mean [SD], 87 [77] vs 242 [120] mL; P < .001). One control (4%) and 2 treatment patients (7%) developed a parenchymal hematoma type 2 (P > .99). The rates of hemicraniectomy (2 [7%] vs 6 [21%]; P = .10) and 90-day mortality (7 [29%] vs 11 [48%]; P = .75) were numerically lower in the intervention arm. Sensitivity analysis for patients with a baseline ischemic core greater than 70 mL (12 pairs) revealed a significant reduction in final infarct volumes (mean [SD], 110 [65] vs 319 [147] mL; P < .001) but only a nonsignificant improvement in the overall distribution of mRS scores favoring the treatment group (P = .18). All 11 patients older than 75 years had poor outcomes (mRS score >3) at 90 days. Conclusions and Relevance In properly selected patients, ET appears to benefit patients with large core and large mismatch profiles. Future prospective studies are warranted.

Early Endovascular Treatment in Intravenous Tissue Plasminogen Activator–Ineligible Patients

Background and Purpose— Intravenous tissue-type plasminogen activator (tPA) treatment in acute stroke has many exclusion criteria. We aimed to assess the safety and efficacy of endovascular therapy (ET) in intravenous (IV) tPA-ineligible patients. Methods— Retrospective analysis of a prospectively collected database of consecutive patients treated with ET within 6 hours of stroke onset between September 2010 and April 2015. Patients treated with IV-tPA followed by ET were compared with those treated with ET alone because of IV-tPA ineligibility. Efficacy and safety end points included the rates of good outcome (90-day modified Rankin scale score ⩽2), successful reperfusion (modified Treatment in Cerebral Ischemia 2b-3), parenchymal hematoma (PH-1 and PH-2), and 90-day mortality. Univariate and logistic regression were performed to identify the predictors of outcomes. Results— A total of 422 patients were included. Two hundred and fifty-three (59%) patients received IV-tPA+ET, and 169 (41%), ET alone. Combined IV-tPA+ET patients were slightly younger (64.9±15.2 versus 67.9±14.9 years; P=0.05), more often males (56% versus 44%; P=0.01), and had less hypertension (70% versus 81%; P=0.02) and vertebrobasilar occlusions (3% versus 8%; P=0.02). The remaining baseline characteristics, including National Institutes of Health Stroke Scale score (20 [15–23] versus 19 [15–24]; P=0.85), Alberta Stroke Program Early CT Score (ASPECTS; 8 [7–9] versus 8 [7–9]; P=0.24), and stroke onset to puncture times (235±70 versus 240±81 minutes; P=0.27), were similar across both groups. There were no significant differences in the rates of modified Treatment in Cerebral Ischemia 2b-3 (83% versus 80%; P=0.52), 90-day modified Rankin scale score ⩽2 (45% versus 38%; P=0.21), or any PH (3% versus 5%; P=0.21). Unadjusted 90-day mortality was higher with ET alone (21% versus 34%; P<0.01); however, IV-tPA ineligibility was not associated with modified Treatment in Cerebral Ischemia 2b-3, any PH, good outcome, or 90-day mortality on logistic regression. Conclusions— IV-tPA-eligible and -ineligible patients seem to have similar outcomes after early ET.

Even Small Decreases in Blood Pressure during Conscious Sedation Affect Clinical Outcome after Stroke Thrombectomy: An Analysis of Hemodynamic Thresholds

BACKGROUND AND PURPOSE: The adverse effects of general anesthesia in stroke thrombectomy have been attributed to intraprocedural hypotension, yet optimal hemodynamic targets remain elusive. Identifying hemodynamic thresholds from patients without exposure to general anesthesia may help separate the effect of hypotension from the effect of anesthesia in thrombectomy outcomes. Therefore, we investigated which hemodynamic parameters and targets best correlate with outcome in patients treated under sedation with monitored anesthesia care. MATERIALS AND METHODS: We performed a retrospective analysis of a prospectively collected data base of patients with anterior circulation stroke who were successfully reperfused (modified TICI ≥ 2b) under monitored anesthesia care sedation from 2010 to 2015. Receiver operating characteristic curves were generated for the lowest mean arterial pressure before reperfusion, both as absolute values and relative changes from baseline. Cutoffs were tested in binary logistic regression models of poor outcome (90-day mRS > 2). RESULTS: Two-hundred fifty-six of 714 patients met the inclusion criteria. In a multivariable model, a ≥10% mean arterial pressure decrease from baseline had an OR for poor outcome of 4.38 (95% CI, 1.53–12.56; P < .01). Other models revealed that any mean pressure of <85 mm Hg before reperfusion had an OR for poor outcome of 2.22 (95% CI, 1.09–4.55; P = .03) and that every 10-mm Hg drop in mean arterial pressure below 100 mm Hg had an OR of 1.28 (95% CI, 1.01–1.62; P = .04). CONCLUSIONS: A ≥10% mean arterial pressure drop from baseline is a strong risk factor for poor outcome in a homogeneous population of patients with stroke undergoing thrombectomy under sedation. This threshold could guide hemodynamic management of patients during sedation and general anesthesia.

Large Volumes of Critically Hypoperfused Penumbral Tissue Do Not Preclude Good Outcomes After Complete Endovascular Reperfusion Redefining Malignant Profile

Background and Purpose— Acute ischemic stroke patients with large volumes of severe hypoperfusion (Tmax>10 s>100 mL) on magnetic resonance imaging have a higher likelihood of intracranial hemorrhage and poor outcomes after reperfusion. We aim to evaluate the impact of the extent of Tmax>10 s CTP lesions in patients undergoing successful treatment. Methods— Retrospective database review of endovascular acute ischemic stroke treatment between September 2010 and March 2015 for patients with anterior circulation occlusions with baseline RAPID CTP and full reperfusion (mTICI 3). The primary outcome was the impact of the Tmax>10 s lesion spectrum on infarct growth. Secondary safety and efficacy outcomes included parenchymal hematomas and good clinical outcomes (90-day modified Rankin Scale score, 0–2). Results— Of 684 treated patients, 113 patients fit the inclusion criteria. Tmax>10 s>100 mL patients (n=37) had significantly higher baseline National Institutes of Health Stroke Scale (20.7±3.8 versus 17.0±5.9; P<0.01), more internal carotid artery terminus occlusions (29% versus 9%; P=0.02), and larger baseline (38.6±29.6 versus 11.7±15.8 mL; P<0.01) and final (60.7±60.0 versus 29.4±33.9 mL; P<0.01) infarct volumes when compared with patients without Tmax>10 s>100 mL (n=76); however, the 2 groups were otherwise well balanced. There were no significant differences in infarct growth (22.1±51.6 versus 17.8±32.4 mL; P=0.78), severe intracranial hemorrhage (PH2: 2% versus 4%; P=0.73), good outcomes (90-day mRS score, 0–2: 56% versus 59%; P=0.83), or 90-day mortality (16% versus 7%; P=0.28). On multivariate analysis, only baseline National Institutes of Health Stroke Scale (odds ratio, 1.19; 95% confidence interval, 1.06–1.34; P<0.01) and baseline infarct core volume (odds ratio, 1.05; 95% confidence interval, 1.02–1.08; P<0.01) were independently associated with Tmax>10 s>100 mL. There was no association between Tmax>10 s>100 mL with any PH, good outcome, or infarct growth. Conclusions— In the setting of limited baseline ischemic cores, large Tmax>10 s lesions on computed tomographic perfusion do not seem to be associated with a higher risk of parenchymal hematomas and do not preclude good outcomes in patients undergoing endovascular reperfusion with contemporary technology.

Cervical Carotid Pseudo-Occlusions and False Dissections: Intracranial Occlusions Masquerading as Extracranial Occlusions

Background and Purpose— Pseudo-occlusion (PO) of the cervical internal carotid artery (ICA) refers to an isolated occlusion of the intracranial ICA that appears as an extracranial ICA occlusion on computed tomography angiography (CTA) or digital subtraction angiography because of blockage of distal contrast penetration by a stagnant column of unopacified blood. We aim to better characterize this poorly recognized entity. Methods— Retrospective review of an endovascular database (2010–2015; n=898). Only patients with isolated intracranial ICA occlusions as confirmed by angiographic exploration were included. CTA and digital subtraction angiography images were categorized according to their apparent site of occlusion as (1) extracranial ICA PO or (2) discernible intracranial ICA occlusion. Results— Cervical ICA PO occurred in 21/46 (46%) patients on CTA (17 proximal cervical; 4 midcervical). Fifteen (71%) of these patients also had PO on digital subtraction angiography. A flame-shaped PO mimicking a carotid dissection was seen in 7 (33%) patients on CTA and in 6 (29%) patients on digital subtraction angiography. Patients with and without CTA PO had similar age (64.8±17.1 versus 60.2±15.7 years; P=0.35), sex (male, 47% versus 52%; P=1.00), and intravenous tissue-type plasminogen activator use (38% versus 40%; P=1.00). The rates of modified Treatment In Cerebral Ischemia 2b-3 reperfusion were 71.4% in the PO versus 100% in the non-PO cohorts (P<0.01). The rates of parenchymal hematoma, 90-day modified Rankin Scale score 0–2, and 90-day mortality were 4.8% versus 8% (P=0.66), 40% versus 66.7% (P=0.12), and 25% versus 21% (P=0.77) in PO versus non-PO patients, respectively. Multivariate analysis indicated that PO patients had lower chances of modified Treatment In Cerebral Ischemia 3 reperfusion (odds ratio 0.14; 95% confidence interval 0.02–0.70; P=0.01). Conclusions— Cervical ICA PO is a relatively common entity and may be associated with decreased reperfusion rates.

Automated CT Perfusion Ischemic Core Volume and Noncontrast CT ASPECTS (Alberta Stroke Program Early CT Score) Correlation and Clinical Outcome Prediction in Large Vessel Stroke

Background and Purpose— The semiquantitative noncontrast CT Alberta Stroke Program Early CT Score (ASPECTS) and RAPID automated computed tomography (CT) perfusion (CTP) ischemic core volumetric measurements have been used to quantify infarct extent. We aim to determine the correlation between ASPECTS and CTP ischemic core, evaluate the variability of core volumes within ASPECTS strata, and assess the strength of their association with clinical outcomes. Methods— Review of a prospective, single-center database of consecutive thrombectomies of middle cerebral or intracranial internal carotid artery occlusions with pretreatment CTP between September 2010 and September 2015. CTP was processed with RAPID software to identify ischemic core (relative cerebral blood flow<30% of normal tissue). Results— Three hundred and thirty-two patients fulfilled inclusion criteria. Median age was 66 years (55–75), median ASPECTS was 8 (7–9), whereas median CTP ischemic core was 11 cc (2–27). Median time from last normal to groin puncture was 5.8 hours (3.9–8.8), and 90-day modified Rankin scale score 0 to 2 was observed in 54%. The correlation between CTP ischemic core and ASPECTS was fair (R=−0.36; P<0.01). Twenty-six patients (8%) had ASPECTS <6 and CTP core ⩽50 cc (37% had modified Rankin scale score 0–2, whereas 29% were deceased at 90 days). Conversely, 27 patients (8%) had CTP core >50 cc and ASPECTS ≥6 (29% had modified Rankin scale 0–2, whereas 21% were deceased at 90 days). Moderate correlations between ASPECTS and final infarct volume (R=−0.42; P<0.01) and between CTP ischemic core and final infarct volume (R=0.50; P<0.01) were observed; coefficients were not significantly influenced by the time from stroke onset to presentation. Multivariable regression indicated ASPECTS ≥6 (odds ratio 4.10; 95% confidence interval, 1.47–11.46; P=0.01) and CTP core ⩽50 cc (odds ratio 3.86; 95% confidence interval, 1.22–12.15; P=0.02) independently and comparably predictive of good outcome. Conclusions— There is wide variability of CTP-derived core volumes within ASPECTS strata. Patient selection may be affected by the imaging selection method.