Selection of Candidates for Endovascular Treatment: Characteristics According to Three Different Selection Methods

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.

Collateral Status and Outcomes after Thrombectomy

Endovascular treatment (EVT) using novel mechanical thrombectomy devices has been the gold standard for patients with acute ischemic stroke caused by large vessel occlusion. Selection criteria of randomized control trials commonly include baseline infarct volume with or without penumbra evaluation. Although the collateral status has been studied and is known to modify imaging results and clinical course, it has not been commonly used for trials. Many post hoc studies, however, revealed that collateral status can help predict infarct growth, recanalization success, decreased hemorrhagic transformation after EVT, and extension of the therapeutic time window for revascularization. Here, we systematically review the recent literature and summarized the outcomes of EVT according to the collateral status of patients with acute ischemic stroke caused by large vessel occlusion. The studies reviewed indicate that pretreatment collateral circulation is associated with both clinical and imaging outcomes after EVT in patients with acute ischemic stroke due to large vessel occlusion although most patients were already selected by other imaging or clinical criteria. However, treatment decisions using information on patients' collateral status have not progressed in clinical practice. Further randomized trials are needed to evaluate the risks and benefits of EVT in consideration of collateral status.

Stroke imaging prior to thrombectomy in the late window: results from a pooled multicentre analysis

BACKGROUND AND PURPOSE

Collateral assessment using CT angiography is a promising modality for selecting patients for endovascular thrombectomy (EVT) in the late window (6-24 hours). The outcome of these patients compared with those selected using perfusion imaging is not clear.

METHODS

We pooled data from seven trials and registries of EVT-treated patients in the late-time window. Patients were classified according to the baseline imaging into collateral imaging alone (collateral cohort) and perfusion plus collateral imaging (perfusion cohort). The primary outcome was the proportion of patients achieving independent 90-day functional outcome (modified Rankin Scale 'mRS' 0-2). We used the propensity score-weighting method to balance important predictors between the cohorts.

RESULTS

In 608 patients, the median onset/last-known-well to emergency arrival time was 8.8 hours and 53.2% had wake-up strokes. Both cohorts had collateral imaging and 379 (62.3%) had perfusion imaging. Independent functional outcome was achieved in 43.1% overall: 168/379 patients (45.5%) in the perfusion cohort versus 94/214 (43.9%) in the collateral cohort (p=0.71). A logistic regression model adjusting for inverse-probability-weighting showed no difference in 90-day mRS score of 0-2 among the perfusion versus collateral cohorts (adjusted OR 1.05, 95% CI 0.69 to 1.59, p=0.83) or in a favourable shift in 90-day mRS (common adjusted OR 1.01, 95% CI 0.69 to 1.47, p=0.97).

CONCLUSION

This pooled analysis of late window EVT showed comparable functional outcomes in patients selected for EVT using collateral imaging alone compared with patients selected using perfusion and collateral imaging.

PROSPERO REGISTRATION NUMBER

CRD42020222003.

Sex-Related Differences in Outcomes After Endovascular Treatment of Patients With Late-Window Stroke

BACKGROUND AND PURPOSE

Sex-related differences exist in many aspects of acute stroke and were mainly investigated in the early time window with conflicting results. However, data regarding sex disparities in late presenters are scarce. Therefore, we sought to investigate differences in outcomes between women and men treated with endovascular treatment in the late time window.

METHODS

Analyses were based on the SOLSTICE Consortium (Selection of Late-Window Stroke for Thrombectomy by Imaging Collateral Extent), which was an individual-patient level analysis of seven trials and registries. Baseline characteristics, 90-day functional independence (modified Rankin Scale score ≤2), mortality, and symptomatic intracranial hemorrhage were compared between women and men. Effect of sex on the association of age and successful reperfusion (final Thrombolysis in Cerebral Infarction 2b-3) with outcomes was assessed using multivariable logistic regression adjusted for age, National Institutes of Health Stroke Scale score, Alberta Stroke Program Early CT Score, time from onset to puncture, occlusion location, intravenous thrombolysis, and successful reperfusion, with interaction terms.

RESULTS

Among 608 patients treated with endovascular treatment, 50.5% were women. Women were older than men (median age of 72 versus 68 years, P=0.02) and had a lower prevalence of tandem occlusions (14.0% versus 22.9%, P=0.005). Workflow times were similar between sexes. Adjusted outcomes did not differ between women and men. Functional independence at 90 days was achieved by 127 out of 292 women (43.5%) and 135 out of 291 men (46.4%). Mortality at 90 days (54 [18.5%] versus 48 [16.5%]) and symptomatic intracranial hemorrhage (37 [13.3%] versus 33 [11.6%]) were similar between women and men. There was no sex-by-age interaction on functional outcomes. However, men had higher likelihood of mortality (P_interaction=0.003) and symptomatic intracranial hemorrhage (P_interaction=0.017) with advancing age. Sex did not influence the relation between successful reperfusion and outcomes.

CONCLUSIONS

In this multicenter analysis of late patients treated with endovascular treatment, sex was not associated with functional outcome. However, sex influenced the association between age and safety outcomes, with men experiencing worse outcomes with advancing age.

Clinical-Diffusion Mismatch Is Associated with Early Neurological Improvement after Late-Window Endovascular Treatment

BACKGROUND

Clinical-diffusion mismatch (CDM) and perfusion-diffusion mismatch (PDM) are used to select patients for endovascular thrombectomy (EVT) in the late-window period. As CDM well reflects true penumbra, we hypothesized that patients with CDM and PDM would respond better to EVT than those with PDM only at the late-window period.

METHODS

Acute ischemic stroke patients who received EVT 6-24 h after stroke onset were included. PDM (perfusion-/diffusion-weighted image (DWI) lesion volume >1.8) was used to select candidates for EVT in this time-period in our center. CDM was defined according to the DAWN trial criteria. Response to EVT was compared between patients with and without CDM. Early neurological improvement (ENI) was defined as improvement >4 points on National Institutes of Health Stroke Scale (NIHSS) score 1 day after EVT. Multivariable analysis was performed to investigate independent factors associated with ENI. The correlation between DWI lesion volume and NIHSS score was investigated in those with and without CDM.

RESULTS

Among 94 patients enrolled, all patients had PDM and 44 (46.3%) had CDM. Forty-eight patients (51.1%) showed ENI. The prevalence of hypertension, initial NIHSS score, improvement in NIHSS score after EVT, and prevalence of ENI were greater in patients with CDM than those without. ENI was independently associated with onset-to-door time (odds ratio [95% confidence interval]: 0.998 [0.997-1.000]; p = 0.042), complete recanalization (23.912 [2.238-255.489]; p = 0.009), initial NIHSS score (1.180 [1.012-1.377]; p = 0.034), and the presence of CDM (5.160 [1.448-18.386]; p = 0.011). The correlation between DWI lesion volume and initial NIHSS score was strong in patients without CDM (r = 0.731) but only moderate in patients with CDM (r = 0.355).

CONCLUSION

Patients with both CDM and PDM had a better response to late-window EVT than those with PDM only.

Endovascular Treatment After Stroke Due to Large Vessel Occlusion for Patients Presenting Very Late From Time Last Known Well

IMPORTANCE

Endovascular treatment (EVT) after ischemic stroke due to emergent large vessel occlusion is usually constrained by a specific window of less than 16 to 24 hours from the time the patient was last known well (LKW). Patients with slow progression and tenacious collateral circulation may persist beyond 16 hours.

OBJECTIVES

To estimate the prevalence of salvageable tissues 16 hours or more from LKW after ischemic stroke due to emergent large vessel occlusion and investigate the effectiveness of EVT in delayed large vessel occlusion.

DESIGN, SETTING AND PARTICIPANTS

In this case-control study, from a total of 8032 patients with stroke or transient ischemic attack who were admitted between January 1, 2012, and December 31, 2018, to a single referral university hospital, 150 patients were retrospectively identified who had an acute ischemic stroke with internal carotid artery or middle cerebral artery occlusion, had a baseline National Institutes of Health Stroke Scale score of 6 or more, and arrived 16 hours or more from time LKW. The decision for EVT was made by a treating physician according to the institutional protocol.

MAIN OUTCOMES AND MEASURES

Baseline ischemic core, collateral circulation status, and computed tomographic or magnetic resonance perfusion parameters were retrospectively quantified. Follow-up images, evaluated a median of 93 hours (interquartile range, 66-120 hours) after arrival, were used to assess the final infarct and hemorrhagic transformation. The main outcome was the modified Rankin Scale score at 90 days.

RESULTS

For 150 patients (81 men [54%]; mean [SD] age at onset, 70.1 [13.0] years; median National Institutes of Health Stroke Scale score, 12 [interquartile range, 8-18]), the median ischemic core volume was 11.5 mL (interquartile range, 0-39.1 mL), the median penumbra volume (>6 seconds) was 55.0 mL (interquartile range, 15-128 mL), and the median mismatch ratio was 4.0 (interquartile range, 0.9-18.3). By the imaging inclusion criteria for EVT trials, there were 50 DAWN (DWI or CTP Assessment With Clinical Mismatch in the Triage of Wake-up and Late Presenting Strokes Undergoing Neurointervention With Trevo)-eligible patients (33%), 58 DEFUSE 3 (Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke)-eligible patients (39%), and 57 ESCAPE (Endovascular Treatment for Small Core and Anterior Circulation Proximal Occlusion With Emphasis on Minimizing CT to Recanalization Times)-eligible patients (38%). Endovascular treatment was performed for 24 patients (16%). In propensity score-matched analyses, EVT was associated with better odds of a 90-day modified Rankin Scale score of 0 to 2 (adjusted odds ratio, 11.08 [95% CI, 1.88-108.60]) and a 90-day modified Rankin Scale score shift (common adjusted odds ratio, 5.17 [95% CI, 1.80-15.62]). Type 2 parenchymal hemorrhage was seen in 3 of 24 patients (13%) who received EVT and in 4 of 126 patients (3%) who received medical management (adjusted odds ratio, 4.06 [95% CI, 0.63-26.30]). In a subgroup of 109 patients who were 24 hours from time LKW, EVT was associated with a favorable mRS shift (common adjusted odds ratio, 10.54 [95% CI, 2.18-59.34]).

CONCLUSIONS AND RELEVANCE

This study suggests that patients with anterior circulation large vessel occlusion presenting very late (>16 hours to 10 days) from the time they were LKW may benefit from EVT.

Pathophysiologic and Therapeutic Perspectives Based on Thrombus Histology in Stroke

Recent advances in endovascular thrombectomy have enabled the histopathologic analysis of fresh thrombi in patients with acute stroke. Histologic analysis has shown that the thrombus composition is very heterogeneous between patients. However, the distribution pattern of each thrombus component often differs between patients with cardiac thrombi and those with arterial thrombi, and the efficacy of endovascular thrombectomy is different according to the thrombus composition. Furthermore, the thrombus age is related to the efficacy of reperfusion therapy. Recent studies have shown that neutrophils and neutrophil extracellular traps contribute to thrombus formation and resistance to reperfusion therapy. Histologic features of thrombi in patients with stroke may provide some clues to stroke etiology, which is helpful for determining the strategy of stroke prevention. Research on thrombus may also be helpful for improving reperfusion therapy, including the development of new thrombolytic agents.