Interaction between intravenous thrombolysis and clinical outcome between slow and fast progressors undergoing mechanical thrombectomy: a post-hoc analysis of the SWIFT-DIRECT trial

Comparison of Noncontrast Computed Tomography, Multiphase Computed Tomography Angiography, and Computed Tomography Perfusion to Assess Infarct Growth Rate in Acute Stroke

BACKGROUND

Infarct growth rate is remarkably heterogeneous in acute ischemic stroke, reflecting diverse clinical-physiological phenotypes. We compared different methods of estimating infarct growth rate in patients with acute ischemic stroke undergoing thrombectomy using multimodal computed tomography (CT) stroke imaging.

METHODS

Secondary analysis of the international ESCAPE-NA1 trial (Efficacy and Safety of Nerinetide for the Treatment of Acute Ischemic Stroke) which evaluated the effect of nerinetide in patients with large vessel occlusion undergoing thrombectomy. Infarct growth rate was estimated leveraging each component of multimodal stroke CT imaging: (1) 10 minus baseline Alberta Stroke Program Early CT Score (ASPECTS) divided by hours elapsed from symptom onset on noncontrast CT (ASPECTS decay per hour); (2) collateral status on multiphase CT angiography (mCTA), and (3) hypoperfusion intensity ratio on CT perfusion. Patients were dichotomized into intermediate and slow progressors (since fast progressors were likely to be excluded from ESCAPE-NA1 based on trial enrollment criteria) according to median ASPECTS decay, presence of good versus moderate/poor mCTA collaterals, and median hypoperfusion intensity ratio, respectively. Associations between progressor phenotypes and 90-day modified Rankin Scale score were assessed across neuroimaging modalities using adjusted logistic regression analyses.

RESULTS

Among 1105 patients enrolled in ESCAPE-NA1 between 2017 and 2019, 619 (56.0%) were assessed for progressor phenotypes using noncontrast CT, 1084 (98.1%) with mCTA, and 415 (37.6%) with CT perfusion. Median ASPECTS decay per hour was 1.05 (interquartile range, 0.05-1.85), 188/1084 (17%) patients had good collateral status on mCTA, and the median hypoperfusion intensity ratio was 0.44 (interquartile range, 0.28-0.59). Intermediate progressors showed worse functional outcomes compared with slow progressors only in CT perfusion strata: adjusted common odds ratio for modified Rankin Scale ordinal shift analysis of 1.69 (95% CI, 1.14-2.49). No significant association between progressor phenotypes and 90-day modified Rankin Scale was seen when the noncontrast CT and the mCTA approaches were used.

CONCLUSIONS

Stroke progressor phenotypes based on CT perfusion criteria (using the hypoperfusion intensity ratio approach) were associated with clinical outcomes, while stroke progressor phenotypes based on noncontrast CT (ASPECTS decay) and mCTA (collateral status) criteria were not.

Infarct Growth in Patients with Emergent Large Vessel Occlusion Stroke Transferred for Endovascular Thrombectomy

INTRODUCTION

Patients with a large vessel occlusion (LVO) stroke who are transferred to a comprehensive stroke center (CSC) for endovascular thrombectomy (EVT) often experience infarct growth. We aimed to investigate the clinical predictors of fast infarct growth and its effect on clinical outcomes.

METHODS

We retrospectively collected EVT data of patients with LVO transferred to our center between March 14, 2019, and June 28, 2022. The absolute rate of Alberta Stroke Program Early Computed Tomography Score (ASPECTS) decay was defined as (ASPECTS primary CT - ASPECTS repeat CT)/elapsed hours. The ratio of relative ASPECTS deterioration was defined as (ASPECTS primary CT - ASPECTS repeat CT)/ASPECTS primary CT. In the primary analysis, the study population was dichotomized into absolute slow progressors and absolute fast progressors using the median absolute rate of ASPECTS decay. Secondary analysis was also conducted using the median relative ASPECTS deterioration ratio, and the study population was categorized into relative fast progressors and relative slow progressors. Favorable outcome was defined as a 90-day modified Rankin Scale (mRS) score ≤ 2.

RESULTS

We included 309 patients: median age 72 years (IQR 65-77); median National Institutes of Health Stroke Scale (NIHSS) 14 (IQR 11-18). The median absolute rate of ASPECTS decay was 0.42 points/hour and the median relative ASPECTS deterioration ratio was 11.1%. Overall, fast infarct growth was independently associated with worse 90-day outcome (absolute rate of ASPECTS decay: OR = 3.395; 95% CI 1.844-6.250; P < 0.001; relative ASPECTS deterioration ratio: OR = 3.754; 95% CI 2.050-6.873; P < 0.001). In multivariable analysis, fast infarct growth was independently associated with high admission NIHSS, proximal occlusions, and poor collateral status, while intravenous thrombolysis before transfer was negative with fast inter-hospital infarct growth.

CONCLUSIONS

For patients with LVO stroke who are transferred from a PSC to CSC for EVT, the infarct growth rate is highly variable and is strongly associated with 90-day outcomes. Initiation of intravenous bridging therapy before transfer may limit the infarct growth during inter-hospital transfer.

Cerebral Infarct Growth: Pathophysiology, Pragmatic Assessment, and Clinical Implications

Cerebral ischemic injury occurs when blood flow drops below a critical level, resulting in an energy failure. The progressive transformation of hypoperfused viable tissue, the ischemic penumbra, into infarction is a mechanism shared by patients with ischemic stroke if timely reperfusion is not achieved. Yet, the pace at which this transformation occurs, known as the infarct growth rate (IGR), exhibits remarkable heterogeneity among patients, brain regions, and over time, reflecting differences in compensatory collateral flow and ischemic tolerance. We review (1) the pathophysiology of infarct growth, (2) the advantages and pitfalls of different approaches of IGR measurement, (3) research gaps for future studies, and (4) the clinical implications of stroke progressor phenotypes. The estimated average IGR in patients with acute large vessel occlusion stroke is 5.4 mL/h although there is wide variability based on ischemic stroke subtype, occlusion location, presence of collaterals, and patient baseline status. The IGR can be calculated using various pragmatic strategies, mostly either quantifying the extension of the infarct at a particular time and dividing this measure by the time that elapsed from symptom onset to imaging assessment or by using collateral blood flow status as a radiological surrogate marker. The IGR defines a spectrum of clinical stroke phenotypes, often dichotomized into fast and slow progressors. An IGR ≥10 mL/h and the perfusion metric hypoperfusion intensity ratio ≥0.5 are commonly used definitions of fast progressors. A nuanced understanding of the IGR and stroke progressor phenotypes could have clinical implications, including informing prognostication, acute decision-making in peripheral-to-comprehensive transfer patients eligible for thrombectomy, and selection for adjuvant neuroprotective agents.

Dynamic Evolution of Infarct Volumes at MRI in Ischemic Stroke Due to Large Vessel Occlusion

BACKGROUND AND OBJECTIVES

The typical infarct volume trajectories in stroke patients, categorized as slow or fast progressors, remain largely unknown. This study aimed to reveal the characteristic spatiotemporal evolutions of infarct volumes caused by large vessel occlusion (LVO) and show that such growth charts help anticipate clinical outcomes.

METHODS

We conducted a secondary analysis from prospectively collected databases (FRAME, 2017-2019; ETIS, 2015-2022). We selected acute MRI data from anterior LVO stroke patients with witnessed onset, which were divided into training and independent validation datasets. In the training dataset, using Gaussian mixture analysis, we classified the patients into 3 growth groups based on their rate of infarct growth (diffusion volume/time-to-imaging). Subsequently, we extrapolated pseudo-longitudinal models of infarct growth for each group and generated sequential frequency maps to highlight the spatial distribution of infarct growth. We used these charts to attribute a growth group to the independent patients from the validation dataset. We compared their 3-month modified Rankin scale (mRS) with the predicted values based on a multivariable regression model from the training dataset that used growth group as an independent variable.

RESULTS

We included 804 patients (median age 73.0 years [interquartile range 61.2-82.0 years]; 409 men). The training dataset revealed nonsupervised clustering into 11% (74/703) slow, 62% (437/703) intermediate, and 27% (192/703) fast progressors. Infarct volume evolutions were best fitted with a linear (r = 0.809; p < 0.001), cubic (r = 0.471; p < 0.001), and power (r = 0.63; p < 0.001) function for the slow, intermediate, and fast progressors, respectively. Notably, the deep nuclei and insular cortex were rapidly affected in the intermediate and fast groups with further cortical involvement in the fast group. The variable growth group significantly predicted the 3-month mRS (multivariate odds ratio 0.51; 95% CI 0.37-0.72, p < 0.0001) in the training dataset, yielding a mean area under the receiver operating characteristic curve of 0.78 (95% CI 0.66-0.88) in the independent validation dataset.

DISCUSSION

We revealed spatiotemporal archetype dynamic evolutions following LVO stroke according to 3 growth phenotypes called slow, intermediate, and fast progressors, providing insight into anticipating clinical outcome. We expect this could help in designing neuroprotective trials aiming at modulating infarct growth before EVT.

Idarucizumab in dabigatran-treated patients with acute stroke: a review and clinical update

Idarucizumab is an antibody fragment specific for the immediate reversal of dabigatran anticoagulation effects. The use of idarucizumab is approved for dabigatran-treated patients suffering from life-threatening or uncontrolled bleeding and those in need of urgent surgery or invasive procedures. Data from randomized controlled clinical trials and real-world experience provide reassuring evidence about the efficacy and safety of idarucizmab use in patients with acute stroke. In this narrative review, we summarize the available real-world evidence and discuss the relevance and importance of idarucizumab treatment in acute stroke patients in everyday clinical practice. In addition, we also discuss special issues like prothrombin complex concentrate application as an alternative to idarucizumab, its application before endovascular therapy, sensitivity of thrombi to lysis, and necessary laboratory examinations.

Intravenous thrombolysis for ischemic stroke in the posterior circulation: A systematic review and meta-analysis

OBJECTIVES

Intravenous thrombolysis (IVT) is recommended in patients with ischemic stroke in the anterior and posterior circulation. Neurological outcomes due to posterior circulation strokes (PCS) without treatment remain poor. Our aim was to overview the literature on outcomes of IVT and conservative treatment in PCS, based on a systematic review and meta-analysis.

METHODS

A systematic literature search was performed on February 27th 2023. Outcome measures included favorable functional outcome at 90 days (modified Rankin Scale [mRS] 0-2), mortality at 90 days, and symptomatic intracranial hemorrhages (sICH). Weighted averages with DerSimonian-Laird approach was used to analyze the data. Subgroup analyses by time window were performed: standard time window (<4.5 hours after symptom onset) and extended time window (>4.5 hours). Analyses were performed using R.

RESULTS

Eight prospective and four retrospective cohort studies were included (n = 1589 patients); no studies with conservative treatment were eligible. The pooled weighted probability regarding favorable functional outcome after IVT was 63 % (95 %CI:0.45-0.78), for mortality 19 % (95 %CI:0.11-0.30), and for sICH 4 % (95 %CI:0.02-0.07). Subgroup analyses showed higher probabilities on achieving favorable functional outcomes for patients treated in the standard (77 %; 95 %CI:0.62-0.88) compared to the extended time window (38 %; 95 %CI:0.29-0.48) with RR = 1.93 (95 %CI:1.66-2.24). Lower probabilities regarding mortality at 90 days and sICH were seen in patients treated in standard compared to extended time window (RR = 0.42, 95 %CI:0.34-0.51 and RR = 0.27, 95 %CI:0.16-0.45, respectively).

CONCLUSIONS

IVT in patients with PCS seems to be safe and effective in standard and extended time window. The effect of IVT is higher in the standard time window.