Early venous drainage after successful endovascular recanalization in ischemic stroke -- a predictor for final infarct volume?

Early venous filling after mechanical thrombectomy in acute ischemic stroke due to large vessel occlusion in anterior circulation

BACKGROUND

The significance of early venous filling (EVF) after mechanical thrombectomy (MT) in acute ischemic stroke (AIS) is not fully understood. In this study, we aimed to investigate the impact of EVF after MT.

METHODS

From January 2019 to May 2022, AIS patients with successful recanalization (modified Thrombolysis in Cerebral Infarction score (mTICI) ≥2b) after MT were retrospectively reviewed. EVF was evaluated on final digital subtraction angiography runs after successful recanalization and was categorized into phase subgroups (arterial phase and capillary phase) and pathway subgroups (cortical veins subgroup and thalamostriate veins subgroup), respectively. The impact of EVF subgroups on functional outcomes after successful recanalization were both investigated.

RESULTS

A total of 349 patients achieving successful recanalization after MT were included, including 45 patients in the EVF group and 304 patients in the non-EVF group. Multivariable logistic regression analysis showed the EVF group had a higher rate of intracranial hemorrhage (ICH; 66.7% vs 22%, adjusted odds ratio (aOR) 6.805, 95% CI 3.389 to 13.662, P<0.001), symptomatic ICH (sICH; 28.9% vs 4.9%, aOR 6.011, 95% CI 2.493 to 14.494, P<0.001) and malignant cerebral edema (MCE; 20% vs 6.9%, aOR 2.682, 95% CI 1.086 to 6.624, P=0.032) than the non-EVF group. Furthermore, the cortical veins subgroup of EVF had a higher rate of mortality than the thalamostriate veins subgroup (37.5% vs 10.3%, P=0.029).

CONCLUSIONS

EVF is independently associated with ICH, sICH and MCE after successful recanalization of MT, but not with favorable outcome and mortality.

Value of Angiographic Regional Circulation Signs in Predicting Hemorrhagic Transformation after Endovascular Thrombectomy

OBJECTIVE

The aim of this study was to evaluate the predictive value of the early venous filling (EVF) sign, the basal ganglia blush (BGB) sign and both the EVF and BGB signs for the hemorrhagic transformation (HT) and parenchymal hematoma (PH) in patients after endovascular thrombectomy.

METHODS

This study included patients with anterior circulation large vessel occlusive stroke treated with endovascular thrombectomy from May 2017 to December 2021. The predictive value of regional circulation signs for HT and PH were assessed using logistic regression models adjusted for confounders, and further a multiplicative interaction term was added to investigate the effect of different stroke severity on its predictive value.

RESULTS

Among the 350 patients included and after adjusting for confounders, those with the EVF sign (adjusted OR=3.934, 95% CI:2.326-6.655), the BGB sign (adjusted OR=3.776, 95% CI:2.341-6.089), and both the EVF and BGB signs (adjusted OR=3.250, 95% CI: 1.886-5.600) were more likely to have HT. The EVF sign (adjusted OR=3.545, 95% CI:2.036-6.170), the BGB sign (adjusted OR=3.742, 95% CI:2.110-6.639), and both the EVF and BGB signs (adjusted OR=3.139, 95% CI: 1.776-5.549) were also significantly correlated with PH. When stratified according to stroke severity, we further found there were significant interactions between regional circulation signs and stroke severity on postoperative HT and PH (all P for interaction < 0.001).

CONCLUSIONS

Regional circulation signs were independently associated with HT and PH after endovascular thrombectomy and had a higher predictive value in patients with severe stroke compared with mild to moderate stroke.

TAGE Score for Symptomatic Intracranial Hemorrhage Prediction After Successful Endovascular Treatment in Acute Ischemic Stroke

BACKGROUND

Determine if early venous filling (EVF) after complete successful recanalization with mechanical thrombectomy in acute ischemic stroke is an independent predictor of symptomatic intracranial hemorrhage (sICH) and integrate EVF into a risk score for sICH prediction.

METHODS

Consecutive patients with anterior acute ischemic stroke treated by mechanical thrombectomy issued from patients enrolled in the THRACE trial (Thrombectomie des Artères Cérébrales) and from 2 prospective registries were included and divided into a derivation (Center I; n=402) and validation cohorts (THRACE and center 2; n=507). EVF was evaluated by 2 blinded readers. sICH was defined according to the modified European cooperative acute stroke study II. Clinical and radiological data were analyzed in the derivation cohort (C1) to identify independent predictors of sICH and construct a predictive score test on the validation cohort (THRACE + C2).

RESULTS

Symptomatic ICH rate was similar between the two cohorts (9.9% and 8.9% respectively, P=0.9). Time from onset-to-successful recanalization >270 minutes (odds ratio [OR], 7.8 [95% CI, 2.5-24]), Alberta Stroke Program Early CT Score (≤5 [OR, 2.49 (95% CI, 1.8-8.1) or 6-7 [OR, 1.15 (95% CI, 1.03-4.46)]), glucose blood level >7 mmol/L (OR, 2.92 [95% CI, 1.26-6.7]), and EVF presence (OR, 11.9 [95% CI, 3.8-37.5]) were independent predictors of sICH and constituted the Time-Alberta Stroke Program Early CT-Glycemia-EVF score. Time-Alberta Stroke Program Early CT-Glycemia-EVF score was associated with an increased risk of sICH in the derivation cohort (OR increase per unit, 1.99 [95% CI, 1.53-2.59]; P<0.001) with area under the curve, 0.832 [95% CI, 0.767-0.898]. The score had good performance in the validation cohort (area under the curve, 0.801 [95% CI, 0.69-0.91]).

CONCLUSIONS

Time-Alberta Stroke Program Early CT-Glycemia-EVF score is a simple tool with readily available clinical variables with good performances for sICH prediction after mechanical thrombectomy.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT01062698.

Intraprocedural Angiographic Signs Observed During Endovascular Thrombectomy in Patients With Acute Ischemic Stroke: A Systematic Review

OBJECTIVE

In the real-world practice of endovascular thrombectomy (EVT) for acute ischemic stroke (AIS), the analysis of intraprocedural angiographic signs (IPASs) still challenges neurointerventionists. This review provides insights into the significance of these subtle changes for predicting underlying etiology, technical feasibility, and patient prognosis, thus promoting the potential real-time application of these signs.

METHODS

A systematic literature search was conducted using PubMed, Ovid Medline/Embase, and Cochrane. The search focused on studies published between January 1995 and August 2020 that reported findings related to intraprocedural angiographic manifestations in endovascular recanalization therapy for AIS.

RESULTS

We identified 12 IPASs in 22 studies involving 1,683 patients. The IPASs were assigned into 3 subsets according to their clinical meanings.

CONCLUSION

The systematic analysis of IPAS in clinical trials and practice will lead to a better understanding of treatment effects, responses, and mechanisms during EVT. Studies of larger cohorts using more robust statistical methods are needed.

Early Venous Filling Following Thrombectomy: Association With Hemorrhagic Transformation and Functional Outcome

Background and Purpose: Previous studies have noted the angiographic appearance of early venous filling (EVF) following recanalisation in acute ischemic stroke. However, the prognostic implications of EVF as a novel imaging biomarker remain unclear. We aimed to evaluate the correlation between EVF with (i) the risk of subsequent reperfusion hemorrhage (RPH) and (ii) the association of EVF on both the NIHSS score at 24 h and functional outcome as assessed with the Modified Rankin Scale (mRS) score at 90 days. Methods: We conducted a retrospective cohort study of patients presenting with an acute ischemic stroke due to a proximal large-vessel occlusion of the anterior circulation treated by thrombectomy. Post-reperfusion digital subtraction angiography was reviewed to look for EVF as evidenced by the contrast opacification of any cerebral vein before the late arterial phase. Results: EVF occurred in 22.4% of the 147 cases included. The presence of EVF significantly increased the risk of RPH (p = 0.0048), including the risk of symptomatic hemorrhage (p = 0.0052). The presence of EVF (p = 0.0016) and the absence of RPH (p = 0.0021) were independently associated with a better outcome as defined by the NIHSS difference at 24 h, most significantly in the EVF⁺RPH^- group. No significant relationship was however found between either EVF or RPH and a mRS score ≤ 2 at 90 days. Conclusion: Early venous filling on angiographic imaging is a potential predictor of reperfusion hemorrhage. The absence of subsequent RPH in this sub-group is associated with better outcomes at 24 h post-thrombectomy than in those with RPH.

Angiographic Blush after Mechanical Thrombectomy is Associated with Hemorrhagic Transformation of Ischemic Stroke

BACKGROUND AND PURPOSE

Risk factors for hemorrhagic transformation of ischemic stroke after mechanical thrombectomy (MT) are not well established. We conducted a study to determine if prominent angiographic cerebral vascularity following recanalization with thrombectomy (angiographic blush) is associated with hemorrhagic transformation.

METHODS

Using the Cornell AcutE Stroke Academic Registry, we identified stroke patients who had thrombectomy and achieved recanalization of anterior circulation large-vessel occlusion between 2012 and 2015. The exposure variable was presence of angiographic blush after recanalization, defined as capillary blush with or without early venous drainage. The primary outcome was volume of hemorrhagic transformation on brain imaging after thrombectomy, as determined by semiautomated volumetric analysis on computed tomography or magnetic resonance imaging among those adjudicated to have hemorrhagic conversion by neuroradiology investigators blinded to angiography results. Using a doubly robust estimator with propensity scores and outcome regression adjusting for demographics and known risk factors for hemorrhagic transformation, we evaluated whether angiographic blush after recanalization is associated with an increased volume of hemorrhagic transformation.

RESULTS

Among 48 eligible patients, 31 (64.6%) had angiographic blush and 26 (54.2%) had radiographic hemorrhagic transformation (mean volume, 7.6 ml). Patients with angiographic blush averaged lower thrombolysis in cerebral infarction scores and more often received intravenous thrombolysis. In adjusted analysis, angiographic blush was associated with an increased volume of hemorrhagic transformation: mean volume, 10.3ml (95% CI, 3.7-16.9 ml) with blush versus 1.8ml (95% Confidence Interval (CII = Confidence Interval), 0.1-3.4 ml) without (P = .01).

CONCLUSIONS

Presence of angiographic blush after MT was independently associated with the volume of hemorrhagic transformation.

Cerebral venous collaterals: A new fort for fighting ischemic stroke?

Stroke therapy has entered a new era highlighted by the use of endovascular therapy in addition to intravenous thrombolysis. However, the efficacy of current therapeutic regimens might be reduced by their associated adverse events. For example, over-reperfusion and futile recanalization may lead to large infarct, brain swelling, hemorrhagic complication and neurological deterioration. The traditional pathophysiological understanding on ischemic stroke can hardly address these occurrences. Accumulating evidence suggests that a functional cerebral venous drainage, the major blood reservoir and drainage system in brain, may be as critical as arterial infusion for stroke evolution and clinical sequelae. Further exploration of the multi-faceted function of cerebral venous system may add new implications for stroke outcome prediction and future therapeutic decision-making. In this review, we emphasize the anatomical and functional characteristics of the cerebral venous system and illustrate its necessity in facilitating the arterial infusion and maintaining the cerebral perfusion in the pathological stroke content. We then summarize the recent critical clinical studies that underscore the associations between cerebral venous collateral and outcome of ischemic stroke with advanced imaging techniques. A novel three-level venous system classification is proposed to demonstrate the distinct characteristics of venous collaterals in the setting of ischemic stroke. Finally, we discuss the current directions for assessment of cerebral venous collaterals and provide future challenges and opportunities for therapeutic strategies in the light of these new concepts.

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.

Venous imaging-based biomarkers in acute ischaemic stroke

Vascular neuroimaging plays a decisive role in selecting the best therapy in patients with acute ischaemic stroke. However, compared with the arterial system, the role of veins has not been thoroughly studied. In this review, we present the major venous imaging-based biomarkers in ischaemic stroke. First, the presence of hypodense veins in the monophasic CT angiography ipsilateral to the arterial occlusion. Second, the asymmetry of venous drainage in the pathological cerebral hemisphere on CT and MRI dynamic angiography. Finally, the presence of hypodense veins on T2* -based MRI. From the physiological point of view, the venous imaging-based biomarkers would detect the alteration of brain perfusion (flow), as well as the optimisation of extraction oxygen mechanisms (misery perfusion). Several studies have correlated the venous imaging-based biomarkers with grade of collateral circulation, the ischaemic penumbra and clinical functional outcome. Although venous imaging-based biomarkers still have to be validated, growing evidence highlights a potential complementary role in the acute stroke clinical decision-making process.

Association of Cortical Vein Filling with Clot Location and Clinical Outcomes in Acute Ischaemic Stroke Patients

Delay in cortical vein filling during the late-venous phase (delayed-LCVF) is characterized by opacification of cerebral veins despite contrast clearance from contralateral veins on dynamic computed tomography angiography (dCTA) in acute ischemic stroke (AIS) patients. The aim of the study was to investigate the associations of delayed-LCVF with clot location, reperfusion status at 24 hours, and 90-days functional outcome in AIS patients who received reperfusion therapy. A prospective cohort of AIS patients treated with intravenous thrombolysis was studied. Groupwise comparison, univariate, and multivariate regression analyses were used to study the association of delayed-LCVF with clot location and clinical outcomes. Of 93 patients (mean age = 72 ± 12 years) with hemispheric AIS included in the study, 46 (49%) demonstrated delayed-LCVF. Patients with delayed-LCVF demonstrated a significantly higher proportion of proximal occlusion (72% vs 13%, P =< 0.0001), and poor reperfusion at 24 hours (41% vs 11%, P = 0.001). The proportion of poor functional outcome at 90 days was not significantly different (22/56 (48%) vs 17/61 (36%), P = 0.297). The appearance of delayed-LCVF on baseline dCTA may be a surrogate for large vessel occlusion, and an early marker for poor 24-hour angiographic reperfusion.

Scoring flow restoration in cerebral angiograms after endovascular revascularization in acute ischemic stroke patients

Endovascular revascularization techniques are increasingly used to treat arterial occlusions in patients with acute ischemic stroke. To monitor and communicate treatment results, a valid, reproducible, and clinically relevant, yet easy to use grading scheme of arterial recanalization and tissue reperfusion for digital subtraction angiography is needed. An ideal scoring system would consider the target arterial lesion, the perfusion deficit, and the collateral status before treatment and measure recanalization, reperfusion, early venous shunting, vasospasm, as well as distal embolization after flow restoration. Currently, a variety of different flow restoration scales are in use, including the Thrombolysis in Myocardial Infarction scoring system, the Thrombolysis in Cerebral Infarction score, and the Arterial Occlusive Lesion score, which describe the local recanalization result. These scores are not used homogeneously throughout the literature, are often modified and not fully documented, which make them inept to compare treatment effects across studies. In addition, none of these scores cover all of the above-mentioned aspects, nor are they able to describe satisfactorily all relevant angiographic findings, and data on their reliability and predictive power regarding clinical outcome are sparse. We aimed to review and illustrate the different revascularization scales, discuss their advantages and limitations as well as the available data regarding standardization, reliability testing, and outcome prediction. In addition, we give examples for the use of the scales and show potential pitfalls.