Outcomes with Endovascular Treatment of Patients with M2 Segment MCA Occlusion in the Late Time Window.

BACKGROUND AND PURPOSE: Randomized trials in the late window have demonstrated the efficacy and safety of endovascular thrombectomy in large-vessel occlusions. Patients with M2-segment MCA occlusions were excluded from these trials. We compared outcomes with endovascular thrombectomy in patients with M2-versus-M1 occlusions presenting 6-24 hours after symptom onset. MATERIALS AND METHODS: Analyses were on pooled data from studies enrolling patients with stroke treated with endovascular thrombectomy 6-24 hours after symptom onset. We compared 90-day functional independence (mRS ≤ 2), mortality, symptomatic intracranial hemorrhage, and successful reperfusion (expanded TICI = 2b-3) between patients with M2 and M1 occlusions. The benefit of successful reperfusion was then assessed among patients with M2 occlusion. RESULTS: Of 461 patients, 367 (79.6%) had M1 occlusions and 94 (20.4%) had M2 occlusions. Patients with M2 occlusions were older and had lower median baseline NIHSS scores. Patients with M2 occlusion were more likely to achieve 90-day functional independence than those with M1 occlusion (adjusted OR = 2.13; 95% CI, 1.25-3.65). There were no significant differences in the proportion of successful reperfusion (82.9% versus 81.1%) or mortality (11.2% versus 17.2%). Symptomatic intracranial hemorrhage risk was lower in patients with M2-versus-M1 occlusions (4.3% versus 12.2%, P = .03). Successful reperfusion was independently associated with functional independence among patients with M2 occlusions (adjusted OR = 2.84; 95% CI, 1.11-7.29). CONCLUSIONS: In the late time window, patients with M2 occlusions treated with endovascular thrombectomy achieved better clinical outcomes, similar reperfusion, and lower symptomatic intracranial hemorrhage rates compared with patients with M1 occlusion. These results support the safety and benefit of endovascular thrombectomy in patients with M2 occlusions in the late window.

Infarct Growth despite Successful Endovascular Reperfusion in Acute Ischemic Stroke: A Meta-analysis.

BACKGROUND: Infarct volume inversely correlates with good recovery in stroke. The magnitude and predictors of infarct growth despite successful reperfusion via endovascular treatment are not known. PURPOSE: We aimed to summarize the extent of infarct growth in patients with acute stroke who achieved successful reperfusion (TICI 2b-3) after endovascular treatment. DATA SOURCES: We performed a systematic review and meta-analysis by searching MEDLINE and Google Scholar for articles published up to October 31, 2020. STUDY SELECTION: Studies of >10 patients reporting baseline and post-endovascular treatment infarct volumes on MR imaging were included. Only patients with TICI 2b-3 were included. We calculated infarct growth at a study level as the difference between baseline and follow-up MR imaging infarct volumes. DATA ANALYSIS: Our search yielded 345 studies, and we included 10 studies reporting on 973 patients having undergone endovascular treatment who achieved successful reperfusion. DATA SYNTHESIS: The mean baseline infarct volume was 19.5 mL, while the mean final infarct volume was 37.5 mL. A TICI 2b reperfusion grade was achieved in 24% of patients, and TICI 2c or 3 in 76%. The pooled mean infarct growth was 14.8 mL (95% CI, 7.9-21.7 mL). Meta-regression showed higher infarct growth in studies that reported higher baseline infarct volumes, higher rates of incomplete reperfusion (modified TICI 2b), and longer onset-to-reperfusion times. LIMITATIONS: Significant heterogeneity among studies was noted and might be driven by the difference in infarct growth between early- and late-treatment studies. CONCLUSIONS: These results suggest considerable infarct growth despite successful endovascular treatment reperfusion and call for a faster workflow and the need for specific therapies to limit infarct growth.

Imaging Triage of Patients with Late-Window (6-24 Hours) Acute Ischemic Stroke: A Comparative Study Using Multiphase CT Angiography versus CT Perfusion.

BACKGROUND AND PURPOSE: The role of collateral imaging in selecting patients for endovascular thrombectomy beyond 6 hours from onset has not been established. To assess the comparative utility of collateral imaging using multiphase CTA in selecting late window patients for EVT. MATERIALS AND METHODS: We used data from a prospective multicenter observational study in which all patients underwent imaging with multiphase CT angiography as well as CTP. Two blinded reviewers evaluated patients' eligibility for endovascular thrombectomy using published collateral imaging (multiphase CTA) criteria compared with CTP using the selection criteria of the Clinical Mismatch in the Triage of Wake Up and Late Presenting Strokes Undergoing Neurointervention with Trevo (DAWN) and Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke 3 (DEFUSE-3) trials. CTP images were processed using automated commercial software. The outcomes of patients eligible for endovascular thrombectomy according to multiphase CTA, DAWN, or DEFUSE-3 criteria were compared using multivariable logistic regression modeling. Model characteristics were compared using the C-statistic for the receiver operating characteristic curve, the Akaike information criterion, and the Bayesian information criterion. RESULTS: Eighty-six patients presented beyond 6 hours from onset/last known well (median, 9.6 hours; interquartile range, 4.1 hours). Thirty-five patients (40.7%) received endovascular thrombectomy, of whom good functional outcome (90-day mRS, 0-2) was achieved in 16/35 (47%). Collateral-based imaging paradigms significantly modified the treatment effect of endovascular thrombectomy on 90-day mRS 0-2 (P interaction = .007). The multiphase CTA-based regression model best fit the data for the 90-day outcome (C-statistic, 0.86; 95% CI, 0.77-0.94) and was associated with the least information loss (Akaike information criterion, 95.7; Bayesian information criterion, 114.9) compared with CTP-based models. CONCLUSIONS: The collateral-based imaging paradigm using multiphase CTA compares well with CTP in selecting patients for endovascular thrombectomy in the late time window.

Imaging of Patients with Suspected Large-Vessel Occlusion at Primary Stroke Centers: Available Modalities and a Suggested Approach.

The overwhelming benefit of endovascular therapy in patients with large-vessel occlusions suggests that more patients will be screened than treated. Some of those patients will be evaluated first at primary stroke centers; this type of evaluation calls for standardizing the imaging approach to minimize delays in assessing, transferring, and treating these patients. Here, we propose that CT angiography (performed at the same time as head CT) should be the minimum imaging approach for all patients with stroke with suspected large-vessel occlusion presenting to primary stroke centers. We discuss some of the implications of this approach and how to facilitate them.

Impact of age and baseline NIHSS scores on clinical outcomes in the mechanical thrombectomy using solitaire FR in acute ischemic stroke study.

BACKGROUND AND PURPOSE: Age and stroke severity are inversely correlated with the odds of favorable outcome after ischemic stroke. A previously proposed score for Stroke Prognostication Using Age and NIHSS Stroke Scale (SPAN) indicated that SPAN-100-positive patients (ie, age + NIHSS score = 100 or more) do not benefit from IV-tPA. If this finding holds true for endovascular therapy, this score can impact patient selection for such interventions. This study investigated whether a score combining age and NIHSS score can improve patients' selection for endovascular stroke therapy. MATERIALS AND METHODS: The SPAN index was calculated for patients in the prospective Solitaire FR Thrombectomy for Acute Revascularization study: an international single-arm multicenter cohort for anterior circulation stroke treatment by using the Solitaire FR. The proportion with favorable outcome (90-day mRS score ≤2) was compared between SPAN-100-positive versus-negative patients. RESULTS: Of the 202 patients enrolled, 196 had baseline NIHSS scores. Fifteen (7.7%) patients were SPAN-100-positive. There was no difference in the rate of successful reperfusion (Thrombolysis In Cerebral Infarction 2b or 3) between SPAN-100-positive versus -negative groups (93.3% versus 82.8%, respectively; P = .3). Stroke SPAN-100-positive patients had a significantly lower proportion of favorable clinical outcomes (26.7% versus 60.8% in SPAN-100-negative, P = .01). In a multivariable analysis, SPAN-100-positive status was associated with lower odds of favorable outcome (OR, 0.3; 95% CI, 0.1-0.9; P = .04). A higher baseline Alberta Stroke Program Early CT Score and a short onset to revascularization time also predicted favorable outcome in the multivariable analysis. CONCLUSIONS: A significantly lower proportion of patients with a positive SPAN-100 achieved favorable outcome in this cohort. SPAN-100 was an independent predictor of favorable outcome after adjusting for time to treatment and the extent of preintervention tissue damage according to the Alberta Stroke Program Early CT Score.

When is carotid angioplasty and stenting the cost-effective alternative for revascularization of symptomatic carotid stenosis? A Canadian health system perspective.

BACKGROUND AND PURPOSE: Carotid revascularization procedures can be complicated by stroke. Additional disability adds to the already high costs of the procedure. To weigh the cost and benefit, we estimated the cost-utility of carotid angioplasty and stenting compared with carotid endarterectomy among patients with symptomatic carotid stenosis, with special emphasis on scenario analyses that would yield carotid angioplasty and stenting as the cost-effective alternative relative to carotid endarterectomy. MATERIALS AND METHODS: A cost-utility analysis from the perspective of the health system payer was performed by using a Markov analytic model. Clinical estimates were based on a meta-analysis. The procedural costs were derived from a microcosting data base. The costs for hospitalization and rehabilitation of patients with stroke were based on a Canadian multicenter study. Utilities were based on a randomized controlled trial. RESULTS: In the base case analysis, carotid angioplasty and stenting were more expensive (incremental cost of $6107) and had a lower utility (-0.12 quality-adjusted life years) than carotid endarterectomy. The results are sensitive to changes in the risk of clinical events and the relative risk of death and stroke. Carotid angioplasty and stenting were more economically attractive among high-risk surgical patients. For carotid angioplasty and stenting to become the preferred option, their costs would need to fall from more than $7300 to $4350 or less and the risks of the periprocedural and annual minor strokes would have to be equivalent to that of carotid endarterectomy. CONCLUSIONS: In the base case analysis, carotid angioplasty and stenting were associated with higher costs and lower utility compared with carotid endarterectomy for patients with symptomatic carotid stenosis. Carotid angioplasty and stenting were cost-effective for patients with high surgical risk.

Mechanical thrombectomy with the Solitaire stent: is there a learning curve in achieving rapid recanalization times?

METHODS: In acute ischemic stroke, good outcome following successful recanalization is time dependent. In patients undergoing endovascular therapy at our institution, recanalization times with the Solitaire stent were retrospectively evaluated to assess for the presence of a learning curve in achieving rapid recanalization. METHODS: We reviewed patients who presented to our stroke center and achieved successful recanalization with the Solitaire stent exclusively. Time intervals were calculated (CT to angiography arrival, angiography arrival to groin puncture, groin puncture to first deployment, and deployment to recanalization) from time stamped images and angiography records. Patients were divided into three sequential groups, with overall CT to recanalization time and subdivided time intervals compared. RESULTS: 83 patients were treated with the Solitaire stent from May 2009 to February 2012. Recanalization (Thrombolyis in Cerebral Infarction score 2A) occurred in 75 (90.4%) patients. CT to recanalization demonstrated significant improvement over time, which was greatest between the first 25 and the most recent 25 cases (161-94 min; p<0.01). The maximal contribution to this was from improvements in first stent deployment to recanalization time (p=0.001 between the first and third groups), with modest contributions from moving patients from CT to the angiography suite faster (p=0.02 between the first and third groups) and from groin puncture to first stent deployment (p=0.02 between the first and third groups). CONCLUSIONS: There is a learning curve involved in the efficient use of the Solitaire stent in endovascular acute stroke therapy. Along with improvements in patient transfer to angiography and improved efficiency with intracranial access, mastering this device contributed significantly towards reducing recanalization times.

CTA collateral status and response to recanalization in patients with acute ischemic stroke.

BACKGROUND AND PURPOSE: Collateral status at baseline is an independent determinant of clinical outcome among patients with acute ischemic stroke. We sought to identify whether the association between recanalization after intra-arterial acute stroke therapy and favorable clinical response is modified by the presence of good collateral flow assessed on baseline CTA. MATERIALS AND METHODS: Data are from the Keimyung Stroke Registry, a prospective cohort study of patients with acute ischemic stroke from Daegu, South Korea. Patients with M1 segment MCA with or without intracranial ICA occlusions on baseline CTA from May 2004 to July 2009 who also had baseline MR imaging were included. Two readers blinded to all clinical information assessed baseline and follow-up imaging. Leptomeningeal collaterals on baseline CTA were assessed by consensus by use of the regional leptomeningeal score. RESULTS: Among 84 patients (mean age, 65.2 ± 13.2 years; median NIHSS score, 14; interquartile range, 8.5), median time from stroke onset to initial MR imaging was 164 minutes. TICI 2b-3 recanalization was achieved in 38.1% of patients and mRS 0-2 at 90 days in 35.8% of patients. In a multivariable model, the interaction between collateral status and recanalization was significant. Only patients with intermediate or good collaterals who recanalized showed a statistically significant association with good clinical outcome (rate ratio = 3.8; 95% CI, 1.2-12.1). Patients with good and intermediate collaterals who did not achieve recanalization and patients with poor collaterals, even if they achieved recanalization, did not do well. CONCLUSIONS: Patients with good or intermediate collaterals on CTA benefit from intra-arterial therapy, whereas patients with poor collaterals do not benefit from treatment.

A meta-analysis of observational intra-arterial stroke therapy studies using the Merci device, Penumbra system, and retrievable stents.

BACKGROUND AND PURPOSE: The time from arterial puncture to successful recanalization is an important milestone toward timely recanalization. With the significant improvement in recanalization rates by using thrombectomy devices, procedural time to recanalization is becoming a determinant factor in choosing among available devices. We aimed to assess the impact of time to recanalization on the outcome of intra-arterial stroke therapies. MATERIALS AND METHODS: We conducted a meta-analysis of studies reporting procedural times in patients with stroke treated with the MD, PS, and RS. RESULTS: We identified 16 eligible studies: 4 on the MD (n = 357), 8 on the PS (n = 455), and 4 on RS (n = 113). Merci device studies described total procedural duration, while PS and RS studies described puncture-to-recanalization times. With a random-effects model, mean procedural duration for the MD was 120 minutes (95% CI, 105.7-134.2 minutes). Mean puncture to recanalization time for the PS was 64.6 minutes (95% CI, 44.4-84.8 minutes) and 54.7 minutes for RS (95% CI, 47.3-62.2 minutes). Successful recanalization was achieved in 211 of 357 patients (59.1%) in the MD studies (95% CI, 49.3-77.7), 394 of 455 (86.6%) in the PS studies (95% CI, 84.1-93.8), and 105 of 113 (92.9%) in the RS studies (95% CI, 90.9-99.9). Functional independence (mRS ≤2) was achieved in 31.5% of patients in the MD studies, 36.6% in the PS studies, and 46.9% in the RS studies. CONCLUSIONS: The use of the PS and RS was associated with comparable procedural time to recanalization. Available data did not allow this parameter to be determined for trials using the MD. Retrievable stents achieved the highest rate of successful recanalization and functional outcome and the lowest mortality.

Subacute seizure incidence in thrombolysis-treated ischemic stroke patients.

BACKGROUND: To assess the incidence of seizures in acute ischemic stroke patients treated with chemical (tPA) thrombolysis. METHODS: Retrospective study including all thrombolysis patients treated in Calgary between January 1, 2001, and October 31, 2006. Descriptive statistics and age/sex-adjusted P values were calculated. RESULTS: Of 400 eligible patients (median age 74.0 years, range: 24-77), 16 (4%) developed post-stroke seizures: 10 (62.5%) within one week (early) and 6 (37.5%) after 1 week but within the hospital stay (late). Single-vessel anterior circulation involvement (93.8% vs. 87%, P = 0.34) and hemorrhage (37.5% vs. 20%, P = 0.15) were more common in those with compared to without seizures but did not reach statistical significance. Atrial fibrillation was more common in those with (56.3%) than without (36.1%) seizures (P = 0.04). Death during admission was more likely (P = 0.03) in those who sustained seizures (37.5%) compared to those without seizures (17.6%). CONCLUSIONS: In this cohort of tPA-treated patients, post-stroke seizures were associated with atrial fibrillation and early mortality.

Outcomes after carotid angioplasty and stenting in symptomatic octogenarians.

OBJECTIVE: Octogenarians were excluded from participation in many carotid endarterectomy trials due to the high complication rates observed in past studies. However, stroke resulting from carotid stenosis is expected to increase with the aging population. Moreover, advances in Carotid Angioplasty and Stenting (CAS) techniques have resulted in perceived improved safety of this procedure. We sought to review our experience with carotid stenting in symptomatic octogenarians with an emphasis on short-term outcomes and complications. METHODS: This is a retrospective longitudinal cohort study of all symptomatic patients who underwent CAS in our center between 1997 and 2007. Thirty-day stroke and death rates, and length of hospitalization were compared between the symptomatic octogenarians and non-octogenarians. RESULTS: A total of 214 procedures were performed on 211 symptomatic patients (56 females). Fifty-nine patients (14 females) were octogenarians. The median (interquartile range) age on procedure date for the octogenarian cohort was 83 (4) years. Periprocedural death occurred in two (3.4%) octogenarians and five (3.3%) non-octogenarians (p = 0.97). At 30 days from the procedure, stroke occurred in four (6.8%) octogenarians and seven (4.6%) non-octogenarians (p= 0.52). The mean hospital stay (4.8 days) was not different between the two cohorts. Age was not a predictor of the 30-day risk of composite stroke or death. CONCLUSION: The complications rate observed in octogenarians was not significantly higher than non-octogenarians. Our findings suggest that octogenarians should be included in randomized trials examining CAS to better define the risk-benefit profile of this procedure in the elderly.

Carotid stenting in asymptomatic carotid stenosis: the Calgary experience.

BACKGROUND: Although carotid endarterectomy is considered the 'gold standard' for standard risk symptomatic patients, the treatment of choice for asymptomatic patients remains controversial. Carotid stenting has demonstrated real-world outcomes consistent with established guidelines for carotid endarterectomy in asymptomatic high-surgical risk patients in recent prospective multicenter trials. We describe our experience with asymptomatic patients who underwent carotid stenting at our center in a routine clinical setting. METHODS: This is a retrospective, longitudinal cohort study of patients who underwent carotid angioplasty and stenting at the Foothills Medical Center, Calgary, Canada between 1997 and 2007. The qualifying events were categorized as symptomatic and asymptomatic. The procedures were performed by four experienced neurointerventionists. The primary outcome was stroke or death at 30-day follow- up. RESULTS: 243 patients underwent 255 carotid stenting procedures. Their ages ranged from 50 to 83 years; the mean age was 72.0 ± 9.3 years; 67(26.3%) were women. Forty one patients (16.1%) were asymptomatic; 214 patients (83.9%) were symptomatic. The patients in the asymptomatic group were significantly younger - 66.0 ± 8.8 years compared to patients in the symptomatic group 73.2 ± 8.9 years (p < 0.0001). Intraprocedurally one minor stroke (2.4%) occurred in the asymptomatic group. At 30-day follow-up, no deaths or further strokes were noted in the asymptomatic group; while eight deaths, six major and seven minor strokes occurred in the symptomatic group (p = 0.22). CONCLUSION: Carotid stenting appears to be a safe procedure in asymptomatic patients with severe carotid stenosis in routine clinical settings as witnessed in this single center study.

Recurrent cerebral ischemia in medically treated patent foramen ovale: a meta-analysis.

BACKGROUND: Among patients with a patent foramen ovale (PFO) and a prior cryptogenic ischemic stroke or TIA, the absolute and relative risk of recurrent events is unclear. METHODS: We conducted a systematic review and meta-analysis of clinical studies in any language published up to February 2008. We included studies reporting original data on recurrent cerebrovascular events in patients with prior cryptogenic stroke or TIA and PFO. Two authors independently extracted data and evaluated study quality. RESULTS: We identified 15 eligible studies, four with a non-PFO comparison group. In these four studies, the pooled relative risk (RR) for recurrent ischemic stroke or TIA in patients with vs without a PFO was 1.1 (95% confidence interval [CI] 0.8 to 1.5). For ischemic stroke, the pooled RR was 0.8 (95% CI 0.5 to 1.3). We tabulated the absolute rate of recurrent events in all 15 studies. The pooled absolute rate of recurrent ischemic stroke or TIA in patients with PFO was 4.0 events per 100 person-years (95% CI 3.0 to 5.1) while the rate of recurrent ischemic stroke was 1.6 events per 100 person-years (95% CI 1.1 to 2.1). CONCLUSIONS: In medically treated patients with prior cryptogenic stroke, while the absolute rate of recurrent events is variable, available evidence does not support an increased relative risk of recurrent ischemic events in those with vs without a patent foramen ovale. Patent foramen ovale closure in these patients cannot be recommended until the results of ongoing clinical trials are reported.