Unknown Onset Stroke: Differences Between Patients with Wake-Up Stroke and Daytime-Unwitnessed Stroke

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.

Wake-up stroke and unknown-onset stroke; occurrence and characteristics from the nationwide Norwegian Stroke Register

Introduction

Population-based knowledge of the characteristics of wake-up stroke and unknown-onset stroke is limited. We compared occurrence and characteristics of ischaemic and haemorrhagic wake-up stroke, unknown-onset stroke and known-onset stroke in a nationwide register-based study.

Patients and methods

We included patients registered in the Norwegian Stroke Register from 2012 through 2019. Age, sex, risk factors, clinical characteristics, acute stroke treatment and discharge destination were compared according to stroke type and time of onset.

Results

Of the 60,320 patients included, 11,451 (19%) had wake-up stroke, 11,098 (18.4%) had unknown time of onset and 37,771 (62.6%) had known symptom onset. The proportion of haemorrhagic stroke was lower among wake-up stroke patients (1107/11,451, 9.7%, 95% CI: 9.1-10.2) than for known-onset stroke (5230/37,771, 13.8%, 95% CI: 13.5-14.2) and for unknown-onset stroke (1850/11,098, 16.7%, 95% CI: 16.0-17.4). Mild stroke (NIHSS <5) was more frequent in ischaemic wake-up stroke (5364/8308, 64.6%, 95% CI: 63.5-65.5) than in known-onset (16,417/26,746, 61.4%, 95% CI: 60.8-62.0) and unknown-onset stroke (3242/5853, 55.4%, 95% CI: 54.1-56.7), while baseline characteristics were otherwise similar to known-onset stroke. Unknown-onset stroke patients were more often female, lived alone and had more severe strokes compared to wake-up stroke and known-onset stroke patients. Unknown-onset stroke patients were more often in need of community-based health care on discharge and had a higher in-hospital mortality.

Discussion and conclusions

Ischaemic wake-up strokes shared baseline characteristics with known-onset strokes, but tended to be milder. Ischaemic unknown-onset stroke patients differed significantly from wake-up stroke, emphasising the importance of considering them as separate entities.

Factors That Influence Susceptibility Vessel Sign in Patients With Acute Stroke Referred for Mechanical Thrombectomy

Background and Purpose

The presence of a Susceptibility Vessel Sign (SVS) in the acute phase of proximal occlusion ischemic stroke indicates the presence of deoxyhemoglobin in the thrombus. Thrombi composition changes over time. The aim of this study was to investigate whether the absence of SVS is associated with a shorter symptom onset to imaging time.

Methods

We retrospectively analyzed all patients referred for mechanical thrombectomy at Besançon University Hospital between 1 January 2015 and 31 December 2020 for whom readable T2^*-weighted imaging was available. We compared patient characteristics according to the presence or absence of an SVS. We also studied the subgroup for whom the exact symptom onset time was known. We performed a univariate statistical analysis, then a multivariate analysis on the variables that were statistically significant in the univariate analysis.

Results

Of the 389 patients included, 309 (79.4%) were SVS+. We found no significant relationship between SVS– and the time between symptom onset and imaging in the whole cohort. In the multivariate analysis, SVS– was associated with anticoagulant treatment (p < 0.01), and SVS+ with age (p = 0.023) and carotid terminus occlusion (p = 0.042). In the known symptom onset subgroup, SVS– was significantly associated with a shorter symptom onset -imaging time (p < 0.001), and this was confirmed in the multivariate analysis (p = 0.011; OR 0.911; 95% CI [0.844; 0.972]).

Conclusion

In the acute phase of proximal occlusion ischemic stroke, absence of SVS was associated with a shorter symptom onset–imaging time for patients with a known symptom onset time.