Wake-Up Stroke versus Stroke with Known Onset Time: Clinical and Multimodality CT Imaging Characteristics

Mode of Onset Modifies the Effect of Time to Endovascular Reperfusion on Clinical Outcomes after Acute Ischemic Stroke: An Analysis of the DAWN Trial

OBJECTIVE

We aimed to assess the impact of time to endovascular thrombectomy (EVT) on clinical outcomes in the DAWN trial, while also exploring the potential effect modification of mode of stroke onset on this relationship.

METHODS

The association between every 1-h treatment delay with 90-day functional independence (modified Rankin Scale [mRS] score 0-2), symptomatic intracranial hemorrhage, and 90-day mortality was explored in the overall population and in three modes of onset subgroups (wake-up vs. witnessed vs. unwitnessed).

RESULTS

Out of the 205 patients, 98 (47.8%) and 107 (52.2%) presented in the 6 to 12 hours and 12 to 24 hours time window, respectively. Considering all three modes of onset together, there was no statistically significant association between time last seen well to randomization with either functional independence or mortality at 90 days in either the endovascular thrombectomy (mRS 0-2 1-hour delay OR 1.07; 95% CI 0.93-1.24; mRS 6 OR 0.84; 95% CI 0.65-1.03) or medical management (mRS 0-2 1-hour delay OR 0.98; 95% CI 0.80-1.14; mRS 6 1-hour delay OR 0.94; 95% CI 0.79-1.09) groups. Moreover, there was no significant interaction between treatment effect and time (p = 0.439 and p = 0.421 for mRS 0-2 and 6, respectively). However, within the thrombectomy group, the models that tested the association between time last seen well to successful reperfusion (modified Treatment in Cerebral Infarction ≥2b) and 90-day functional independence showed a significant interaction with mode of presentation (p = 0.013). This appeared to be driven by a nominally positive slope for both witnessed and unwitnessed strokes versus a significantly (p = 0.018) negative slope in wake-up patients. There was no association between treatment times and symptomatic intracranial hemorrhage.

INTERPRETATION

Mode of onset modifies the effect of time to reperfusion on thrombectomy outcomes, and should be considered when exploring different treatment paradigms in the extended window. ANN NEUROL 2024.

Diffusion-/perfusion-weighted imaging fusion to automatically identify stroke within 4.5 h

OBJECTIVES

We aimed to develop machine learning (ML) models based on diffusion- and perfusion-weighted imaging fusion (DP fusion) for identifying stroke within 4.5 h, to compare them with DWI- and/or PWI-based ML models, and to construct an automatic segmentation-classification model and compare with manual labeling methods.

METHODS

ML models were developed from multimodal MRI datasets of acute stroke patients within 24 h of clear symptom onset from two centers. The processes included manual segmentation, registration, DP fusion, feature extraction, and model establishment (logistic regression (LR) and support vector machine (SVM)). A segmentation-classification model (X-Net) was proposed for automatically identifying stroke within 4.5 h. The area under the receiver operating characteristic curve (AUC), sensitivity, Dice coefficients, decision curve analysis, and calibration curves were used to evaluate model performance.

RESULTS

A total of 418 patients (≤ 4.5 h: 214; > 4.5 h: 204) were evaluated. The DP fusion model achieved the highest AUC in identifying the onset time in the training (LR: 0.95; SVM: 0.92) and test sets (LR: 0.91; SVM: 0.90). The DP fusion-LR model displayed consistent positive and greater net benefits than other models across a broad range of risk thresholds. The calibration curve demonstrated the good calibration of the DP fusion-LR model (average absolute error: 0.049). The X-Net model obtained the highest Dice coefficients (DWI: 0.81; Tmax: 0.83) and achieved similar performance to manual labeling (AUC: 0.84).

CONCLUSIONS

The automatic segmentation-classification models based on DWI and PWI fusion images had high performance in identifying stroke within 4.5 h.

CLINICAL RELEVANCE STATEMENT

Perfusion-weighted imaging (PWI) fusion images had high performance in identifying stroke within 4.5 h. The automatic segmentation-classification models based on DWI and PWI fusion images could provide clinicians with decision-making guidance for acute stroke patients with unknown onset time.

KEY POINTS

• The diffusion/perfusion-weighted imaging fusion model had the best performance in identifying stroke within 4.5 h. • The X-Net model had the highest Dice and achieved performance close to manual labeling in segmenting lesions of acute stroke. • The automatic segmentation-classification model based on DP fusion images performed well in identifying stroke within 4.5 h.

Characteristics and outcomes of unknown onset stroke: The Japan Stroke Data Bank

BACKGROUND

Clinical outcomes of unknown onset stroke (UOS) are influenced by the enlargement of the therapeutic time window for reperfusion therapy. This study aimed to investigate and describe the characteristics and clinical outcomes of patients with UOS.

METHODS

Patients with acute ischemic stroke (AIS) who were admitted within 24 h of their last known well time, from January 2017 to December 2020, were included. Data were obtained from a long-lasting nationwide hospital-based multicenter prospective registry: the Japan Stroke Data Bank. The co-primary outcomes were the National Institutes of Stroke Scale (NIHSS) scores on admission and unfavorable outcomes at discharge, corresponding to modified Rankin Scale (mRS) scores of 3-6.

RESULTS

Overall, 26,976 patients with AIS were investigated. Patients with UOS (N = 5783, 78 ± 12 years of age) were older than patients with known onset stroke (KOS) (N = 21,193, 75 ± 13 years of age). Age, female sex, higher premorbid mRS scores, atrial fibrillation, and congestive heart failure were associated with UOS in multivariate analysis. UOS was associated with higher NIHSS scores (median = 8 [interquartile range [IQR]: 3-19] vs. 4 [1-10], adjusted incidence rate ratio = 1.37 [95% CI: 1.35-1.38]) and unfavorable outcomes (52.1 vs. 33.6%, adjusted odds ratio = 1.27 [1.14-1.40]). Intergroup differences in unfavorable outcomes were attenuated among females (1.12 [0.95-1.32] vs. males 1.38 [1.21-1.56], P = 0.040) and in the subgroup that received reperfusion therapy (1.10 [0.92-1.33] vs. those who did not receive therapy 1.23 [1.08-1.39], P = 0.012).

CONCLUSIONS

UOS was associated with unfavorable outcomes but to a lesser degree among females and patients receiving reperfusion therapy.

CT perfusion - an up-to-date element of the contemporary multimodal diagnostic approach to acute ischemic stroke

Acute ischemic stroke is of great clinical and societal importance due to its high incidence and mortality rates, as well as the fact that those who are affected suffer from permanent acquired disability. Modern trends explicitly state that the disease's diagnostic plan should use a multidisciplinary approach. The therapeutic steps that ultimately determine the clinical outcome are defined by an accurate diagnosis of acute ischemic stroke. Highly specialized facilities for the diagnosis and treatment of acute ischemic stroke (Stroke Units) are in operation in countries that make significant investments in healthcare. Imaging the brain parenchyma at risk, or the so-called ischemic penumbra, in acute ischemic stroke is one of the main tasks of the multimodal computed tomography approach. The most rapid method for imaging the ischemic penumbra is computed tomography perfusion (CTP). This modality provides information about the anatomy and the physiologic state of the brain parenchyma.

Ischemic stroke with unknown onset of symptoms: current scenario and perspectives for the future

BACKGROUND

Stroke is a major cause of disability worldwide and a neurological emergency. Intravenous thrombolysis and mechanical thrombectomy are effective in the reperfusion of the parenchyma in distress, but the impossibility to determine the exact time of onset was an important cause of exclusion from treatment until a few years ago.

OBJECTIVES

To review the clinical and radiological profile of patients with unknown-onset stroke, the imaging methods to guide the reperfusion treatment, and suggest a protocol for the therapeutic approach.

METHODS

The different imaging methods were grouped according to current evidence-based treatments.

RESULTS

Most studies found no difference between the clinical and imaging characteristics of patients with wake-up stroke and known-onset stroke, suggesting that the ictus, in the first group, occurs just prior to awakening. Regarding the treatment of patients with unknown-onset stroke, four main phase-three trials stand out: WAKE-UP and EXTEND for intravenous thrombolysis, and DAWN and DEFUSE-3 for mechanical thrombectomy. The length of the therapeutic window is based on the diffusion weighted imaging-fluid-attenuated inversion recovery (DWI-FLAIR) mismatch, core-penumbra mismatch, and clinical core mismatch paradigms. The challenges to approach unknown-onset stroke involve extending the length of the time window, the reproducibility of real-world imaging modalities, and the discovery of new methods and therapies for this condition.

CONCLUSION

The advance in the possibilities for the treatment of ischemic stroke, while guided by imaging concepts, has become evident. New studies in this field are essential and needed to structure the health care services for this new scenario.

Surrogate biomarkers of outcome for wake-up ischemic stroke

Background

Wake-up ischemic stroke (IS) has been usually excluded from acute stroke therapy options for being outside of the safe treatment window. We identified risk factors, and clinical or molecular biomarkers that could be therapeutic targets for wake-up stroke prevention, thus hopefully leading to a decrease in its mortality and disability in medium to long-term outcome.

Methods

4251 ischemic stroke (IS) patients from a prospectively registered database were recruited; 3838 (90.3%) had known onset-symptom time, and 413 (9.7%) were wake-up strokes. The main endpoint was to analyze the association between different serum biomarkers with wake-up IS episodes and their progression. Leukocytes count, serum levels of C-reactive protein, fibrinogen, interleukin 6 (IL-6), and vitamin D were analyzed as inflammation biomarkers; N-terminal pro-B-type Natriuretic-Peptide and microalbuminuria, used as atrial/endothelial dysfunction biomarkers; finally, glutamate levels as excitotoxicity biomarker. In addition, demographic, clinical and neuroimaging variables associated with the time-evolution of wake-up IS patients and functional outcome at 3 months were evaluated. Good and poor functional outcome were defined as mRS ≤2 and mRS > 2 at 3 months, respectively.

Results

Wake-up IS showed a poorer outcome at 3-months than in patients with known on-set-symptom time (59.1% vs. 48.1%; p < 0.0001). Patients with wake-up IS had higher levels of inflammation biomarkers; IL-6 levels at admission (51.5 ± 15.1 vs. 27.8 ± 18.6 pg/ml; p < 0.0001), and low vitamin D levels at 24 h (5.6 ± 5.8 vs. 19.2 ± 9.4 ng/ml; p < 0.0001) are worthy of attention. In a logistic regression model adjusted for vitamin D, OR was 15.1; CI 95%: 8.6–26.3, p < 0.0001. However, we found no difference in vitamin D levels between patients with or without clinical-DWI mismatch (no: 18.95 ± 9.66; yes: 17.84 ± 11.77 ng/mL, p = 0.394). No difference in DWI volume at admission was found (49.3 ± 96.9 ml in wake-up IS patients vs. 51.7 ± 98.2 ml in awake IS patients; p = 0.895).

Conclusions

Inflammatory biomarkers are the main factors that are strongly associated with wake-up IS episodes. Wake-up IS is associated with lower vitamin D levels. These data indicate that vitamin D deficiency could become a therapeutic target to reduce wake-up IS events.

OUP accepted manuscript

The recanalization effect of large-vessel occlusion (LVO) in anterior circulation is well documented but only some patients benefit from endovascular treatment. We analysed clinical and radiological factors determining clinical outcome after successful mechanical intervention. We included 146 patients from the Prague 16 study enrolled from September 2012 to December 2020, who had initial CT/CTA examination and achieved good recanalization status after mechanical intervention (TICI 2b-3). One hundred and six (73%) patients achieved a good clinical outcome (modified Rankin Scale 0–2 in 3 months). It was associated with age, leptomeningeal collaterals (LC), onset to intervention time, ASPECTS, initial NIHSS, and leukoaraiosis (LA) in univariate analysis. The regression model identified good collateral status [odds ratio (OR) 5.00, 95% confidence interval (CI) 1.91–13.08], late thrombectomy (OR 0.24, 95% CI 0.09–0.65), LA (OR 0.44, 95% CI 0.19–1.00), ASPECTS (OR 1.45, 95% CI 1.08–1.95), and NIHSS score (OR 0.86, 95% CI 0.78–0.95) as independent outcome determinants. In the late thrombectomy subgroup, 14 out of 33 patients (42%) achieved a favourable clinical outcome, none of whom with poor collateral status. The presence of LC and absence of LA predicts a good outcome in acute stroke patients after successful recanalization of LVO in anterior circulation. Late thrombectomy was associated with higher rate of unfavourable clinical outcome. Nevertheless, collateral status in this subgroup was validated as a reliable selection criterion.

Multimodal CT Imaging Characteristics in Predicting Prognosis of Wake-Up Stroke

Background: Multimodal CT imaging can evaluate cerebral hemodynamics and stroke etiology, playing an important role in predicting prognosis. This study aimed to summarize the comprehensive image characteristics of wake-up stroke (WUS), and to explore its value in prognostication.

Methods: WUS patients with anterior circulation large vessel occlusion were recruited into this prospective study. According to the 90-day modified Rankin Scale (mRS), all patients were divided into good outcome (mRS 0–2) or bad (mRS 3–6). Baseline clinical information, multimodal CT imaging characteristics including NECT ASPECTS, clot burden score (CBS), collateral score, volume of penumbra and ischemic core on perfusion were compared. Multivariate logistic regression analysis was further used to analyze predictive factors for good prognosis. Area under curve (AUC) was calculated from the receiver operating characteristic (ROC) curve to assess prognostic value.

Results: Forty WUS were analyzed in this study, with 20 (50%) achieving good outcome. Upon univariable analysis, the good outcome group demonstrated higher ASPECTS, higher CBS, higher rate of good collateral filling and lower penumbra volume when compared with the poor outcome group. Upon logistic regression analysis, poor outcome significantly correlated with penumbra volume (OR: 1.023, 95% CI = 1.003–1.043) and collateral score (OR: 0.140, 95% CI = 0.030–0.664). AUC was 0.715 for penumbra volume (95% CI, 0.550–0.846) and 0.825 for good collaterals (95% CI, 0.672–0.927) in predicting outcome.

Conclusions:Penumbra volume and collateral score are the most relevant baseline imaging characters in predicting outcome of WUS patients. These imaging characteristics might be instructive to treatment selection. As the small sample size of current study, further studies with larger sample size are needed to confirm these observations.

CT Imaging Characteristics and Influence Factors of Renal Dialysis-Associated Peritoneal Injury

Peritoneal dialysis (PD), as one of the main renal replacement modalities for end-stage renal disease, gets the advantages of better protection of residual renal function and better quality of survival. However, ultrafiltration failure after peritoneal injury is an important reason for patients to withdraw from PD treatment. Peritonitis is a major complication of peritoneal dialysis, which results in an accelerated process of peritoneal injury due to direct damage from acute inflammation and local release of cytokine TGF-β. In this paper, the application of ultrasound to examine the peritoneum revealed a positive correlation between peritoneal thickness and the development of peritonitis. The results of this study also further confirmed the effect of peritonitis on peritoneal thickening. A multifactorial regression analysis also revealed that peritonitis and its severity were independent risk factors for peritoneal thickening and omental structural abnormalities. This paper reported a correlation between mural peritoneal thickness and peritoneal transit function. In this study, patients with high peritoneal transit and high mean transit were found to be more prone to omental structural abnormalities than patients with low mean and low transit and a higher proportion of patients with mural peritoneal thickening, but this did not reach statistical significance, which may be related to the still small number of cases.

Thrombolytic therapy for wake-up stroke: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

According to evidence-based clinical practice guidelines, patients presenting with disabling stroke symptoms should be treated with intravenous tissue plasminogen activator (IV tPA) within 4.5 h of time last known well. However, 25% of strokes are detected upon awakening (i.e., wake-up stroke [WUS]), which renders patients ineligible for IV tPA administered via time-based treatment algorithms, because it is impossible to establish a reliable time of symptom onset. We performed a systematic review and meta-analysis of the efficacy and safety of IV tPA compared with normal saline, placebo, or no treatment in patients with WUS using imaging-based treatment algorithms.

METHODS

We searched MEDLINE, Web of Science, and Scopus between January 1, 2006 and April 30, 2020. We included controlled trials (randomized or nonrandomized), observational cohort studies (prospective or retrospective), and single-arm studies in which adults with WUS were administered IV tPA after magnetic resonance imaging (MRI)- or computed tomography (CT)-based imaging. Our primary outcome was recovery at 90 days (defined as a modified Rankin Scale [mRS] score of 0-2), and our secondary outcomes were symptomatic intracranial hemorrhage (sICH) within 36 h, mortality, and other adverse effects.

RESULTS

We included 16 studies that enrolled a total of 14,017 patients. Most studies were conducted in Europe (37.5%) or North America (37.5%), and 1757 patients (12.5%) received IV tPA. All studies used MRI-based (five studies) or CT-based (10 studies) imaging selection, and one study used a combination of modalities. Sixty-one percent of patients receiving IV tPA achieved an mRS score of 0 to 2 at 90 days (95% confidence interval [CI]: 51%-70%, 12 studies), with a relative risk (RR) of 1.21 compared with patients not receiving IV tPA (95% CI: 1.01-1.46, four studies). Three percent of patients receiving IV tPA experienced sICH within 36 h (95% CI: 2.5%-4.1%; 16 studies), which is an RR of 4.00 compared with patients not receiving IV tPA (95% CI: 2.85-5.61, seven studies).

CONCLUSIONS

This systematic review and meta-analysis suggests that IV tPA is associated with a better functional outcome at 90 days despite the increased but acceptable risk of sICH. Based on these results, IV tPA should be offered as a treatment for WUS patients with favorable neuroimaging findings.

A Novel Fast CT Perfusion Core-Penumbra Mismatch Score: Correlation With Stroke Outcome

BACKGROUND

Advanced neuroimaging can identify patients who can most benefit from reperfusion treatment, discriminating between ischemic core and penumbra area in a quick and accurate manner. Despite core-penumbra mismatch being an independent prognostic factor, computed tomography perfusion (CTP) assessment is still debated in hyperacute decision-making. The authors aimed to study a novel CTP mismatch score in emergency settings and to investigate its relation with clinical outcome in acute ischemic stroke patients treated with intravenous thrombolysis (IVT).

METHODS

Neuroimaging and clinical data of 226 consecutive acute ischemic stroke patients were analyzed. The study population was divided into 5 different CTP scores: (0) without perfusion deficit, (1) only penumbra, (2) penumbra > core, (3) core ≥ penumbra, (4) only core. For differences in outcome between treated and nontreated patients, and among CTP core-penumbra groups to be assessed, the authors have evaluated the outcome in terms of National Institutes of Health Stroke Scale (NIHSS) and modified Rankin scale (mRS) at discharge and symptomatic intracerebral hemorrhage.

RESULTS

A decrease in NIHSS was statistically greater in IVT-treated patients compared to nontreated patients showing only penumbra (ΔNIHSS%: 80.0% vs. 50.0%; P=0.0023) or no perfusion deficit (ΔNIHSS%: 89.4% vs. 61.5%; P=0.027) on CTP maps. The same trend was found in other groups without significant difference. A significant correlation was found in IVT patients between core/penumbra score and outcome in terms of ΔNIHSS (Kendall τ=-0.19; P=0.004).

CONCLUSIONS

The authors proposed a novel immediate CTP assessment to score perfusion mismatch in emergency settings to guide clinicians' decision-making for aggressive treatment and to prevent stroke-related disability.

Stroke Treatment With PAR-1 Agents to Decrease Hemorrhagic Transformation

Ischemic stroke is the most widespread cause of disability and a leading cause of death in developed countries. To date, the most potent approved treatment for acute stroke is recanalization therapy with thrombolytic drugs such as tissue plasminogen activator (rt-PA or tPA) or endovascular mechanical thrombectomy. Although tPA and thrombectomy are widely available in the United States, it is currently estimated that only 10-20% of stroke patients get tPA treatment, in part due to restrictive selection criteria. Recently, however, tPA and thrombectomy selection criteria have loosened, potentially allowing more patients to qualify. The relatively low rate of treatment may also reflect the perceived risk of brain hemorrhage following treatment with tPA. In translational research and a single patient study, protease activated receptor 1 (PAR-1) targeted therapies given along with thrombolysis and thrombectomy appear to reduce hemorrhagic transformation after recanalization. Such adjuncts may likely enhance the availability of recanalization and encourage more physicians to use the recently expanded selection criteria for applying recanalization therapies. This narrative review discusses stroke therapies, the role of hemorrhagic transformation in producing poor outcomes, and presents the data suggesting that PAR-1 acting agents show promise for decreasing hemorrhagic transformation and improving outcomes.

[Retrospective analysis of endovascular thrombectomy in anterior cerebral circulation out of 6-hours «therapeutic window» in regional vascular centers of Saint-Petersburg]

OBJECTIVE

Based on a retrospective analysis, to evaluate technical results and functional outcomes at discharge after endovascular thrombectomy (EVT) in anterior circulation out of 6-hours «therapeutic window» in patients with stroke.

MATERIAL AND METHODS

The retrospective analysis of EVT in 594 acute stroke patients (303 male, 291 female, median age 69 years) with the anterior circulation large vessel occlusion was performed. EVT was carried out before 6 hrs in 550, later in 44 patients. Time to artery puncture was defined as a cut point. Patients were included in the study if they met the criterion for 0-6 hours «therapeutic window».

RESULTS

No significant differences in functional outcomes at discharge assessed with the Rankin scale (mRs 0-2 29.8% and 20.5% p<0.19; mRs 3-5 38.7% and 38.6% p<0.99; mRs 6 31.5% and 40.9% p<0.2) and the rates of intracranial haemorrhage, haemorrhagic transformation and symptomatic haemorrhagic transformation (4% and 0% p<0.17; 20.9% and 29.5% p<0.49; 10.1% and 11.4% p<0.78) were observed in patients exposed to EVT before 6 hrs and later.

CONCLUSION

EVT in anterior circulation stroke over 6 hrs «therapeutic window» based on the criterion for 0-6 hrs provides comparable functional outcomes at discharge without the increase in the frequency of intracranial haemorrhages, haemorrhagic and symptomatic haemorrhagic transformations.

Effect of the Number of Neurointerventionalists on Off-Hour Endovascular Therapy for Acute Ischemic Stroke Within 12 Hours of Symptom Onset

Background

Off‐hour presentation can affect treatment delay and clinical outcomes in endovascular therapy (EVT) for acute ischemic stroke. We aimed to examine the treatment delays and clinical outcomes of EVT between on‐ and off‐hour admission and to evaluate the effect of hospital procedure volume and the number of neurointerventionalists on off‐hour EVT.

Methods and Results

From a multicenter registry, we identified patients who were treated with EVT within 12 hours of symptom. Annual hospital procedure volume was divided as low (<30), medium (30–60), and high (>60). The effect of the number of neurointerventionalists and annual hospital procedure volume on clinical outcome was estimated by the generalized estimation equation. Of the 31 133 stroke patients, 1564 patients met the eligibility criteria (mean age: 69±12 years; median baseline National Institutes of Health stroke scale score, 15 [interquartile range, 10–19]). Of 1564 patients, 893 (57.1%) arrived during off‐hour. The off‐hour patients had greater median door‐to‐puncture time (110  versus 95 minutes; P<0.001) compared with on‐hour patients. Despite the treatment delay, the functional outcome at 3 months did not differ between off‐ and on‐hour (odds ratio with 95% CI for 3‐month modified Rankin Scale 0–2, 0.99 [0.78–1.25]; P=0.90). The presence of three neurointerventionalists was significantly associated with favorable outcomes at 3 months during on‐ and off‐hour (2.07 [1.53–2.81]; P<0.001). The association was not observed for annual hospital procedural volume and the functional outcomes.

Conclusions

The number of neurointerventionalists was more crucial to effective around‐the‐clock EVT for acute stroke patients than hospital procedural volume.