Seasonal Variations in Neurological Severity and Outcomes of Ischemic Stroke - 5-Year Single-Center Observational Study

Transportation for Patients with Stroke in Need of Mechanical Thrombectomy: A Simulation-Based Study in Hyogo Prefecture, Japan

Objective

This study aimed to simulate patient transportation to a mechanical thrombectomy (MT)-capable hospital within 60 minutes, taking into account patient volume (demand side of healthcare) and hospital capacity to accept patients (supply side of healthcare).

Methods

Simulations were conducted in Hyogo Prefecture, Japan. The estimates of the annual number of patients with stroke eligible for MT in 2020 were based on the incidence of stroke by age group and the percentage of patients with stroke indicated for MT in existing publications. Patients were then randomly placed on a 1 km2 mesh map. The patients were randomly generated 100 times using R software (version 4.1.2; R Foundation for Statistical Computing, Vienna, Austria). Hospitals were selected based on 2 criteria: (1) actual provision patterns (39 hospitals) and (2) consolidated patterns (12 hospitals). Simulations were performed using ArcGIS Pro (version 10.8; Esri, Redlands, CA, USA) and Network Analyst extension (Esri) in 3 cases: (1) number of patients estimated from the population in 2020 transported to hospitals that provided MT, (2) number of patients estimated based on the 2020 population transported to selected hospitals in the case of consolidation, and (3) number of patients estimated based on 2040's projected population and transportation to the selected hospitals.

Results

In Case 1, the estimated annual number of patients undergoing MT in 2020 was 976. The average number of patients undergoing MT and transported was 961, indicating that 98% (961/976) of the total generated patients could be transported within 60 min. In Case 2, the average number of patients undergoing MT and transported was 940, indicating that 96.3% (940/976) of the total patients could be transported within 60 min. In Case 3, the average number of patients undergoing MT and transported was 1184, showing that 95.1% (1184/1244) of the total generated patients could be transported within 60 min. A few patients in rural areas and remote islands required longer transport times.

Conclusion

The simulations showed that patient estimates from the incidence of cerebral infarction by age group and the percentage of patients with stroke indicated for MT were similar to the actual values. The simulation was closed to reality when both the supply and demand sides of healthcare were considered. Thus, this simulation study informs future healthcare policy by demonstrating the geographic distribution of human and capital resources and potential cost reduction through consolidation, taking into account demographic changes.

Association between ambient temperature and stroke risk in high-risk populations: a systematic review

Background

Significant associations exist between ambient temperature and stroke risk, but results in high cardiovascular risk populations are lacking. This systemic review summarised current evidence on ambient temperature and overall stroke risk in a high cardiovascular risk population.

Methods

We performed a systematic literature search across MEDLINE, Embase, PsycINFO, CINAHL, Web of Science, and GEOBASE, from inception to 3 July 2023, to identify all population-based studies. Eligible studies screened by independent reviewers recruited individuals aged 18 years and over, where minimum 80% of participants had a high cerebral vascular disease (CVD) risk profile. The primary outcomes are stroke morbidity and mortality, while the secondary outcomes are morbidity and mortality of ischaemic stroke (IS), intracranial cerebral haemorrhage (ICH), and subarachnoid haemorrhage (SH).

Results

The database searches identified 9,025 articles. After removing duplicates, 7,647 articles were screened in title and abstract to identify 380 articles for full-text screening. After the full-text screening of 380 articles by two independent reviewers, 23 articles were included in the review.

Conclusion

The evidence for an association between ambient temperature and stroke incidence is that lower temperatures were more likely to increase morbidity and mortality risk of both haemorrhagic and ischaemic stroke in older people. Conversely, higher ambient temperature is significantly associated with intracranial haemorrhage risk, but decreased risk with IS. Higher and lower ambient temperatures consistently increase stroke risks in patients with comorbidities of congestive heart failure and dyslipidaemia. This evidence implies the need to establish clinical guidelines for preventive intervention in patients with high stroke risks during extreme ambient temperatures.

Seasonal Variation in Neurological Severity and Clinical Outcomes in Ischemic Stroke Patients - A 9-Year Study of 5,238 Patients

BACKGROUND

Because the effects of extreme weather conditions on stroke severity and outcomes are unclear, we evaluated seasonal variations in stroke severity and clinical outcomes.

METHODS AND RESULTS

Between 2012 and 2020 we enrolled 5,238 patients with acute ischemic stroke, who were divided into 4 seasons according to stroke onset: spring, summer, autumn and winter. We analyzed the effect of season on the severity and outcomes of all subjects. Multivariable analysis showed that the winter group had 1.234-fold increased risk of moderate-to-severe neurological deficits than the summer group (95% confidence interval (CI): 1.034-1.472, P=0.020). Compared with the summer group, the winter and the spring groups experienced 1.243- and 1.251-fold the risk of suffering from worse outcomes among all patients at 6-month follow-up (95% CI 1.008-1.534, P=0.042, 95% CI 1.013-1.544, P=0.037). The 1-year follow-up revealed similar results. Further comparison of each season in the 2012-2015 and 2016-2020 periods found that the proportion of poor outcomes in the latter autumn group was lower than that in the former time period, with significant differences in both 6-month and 1-year follow-up.

CONCLUSIONS

The onset season was related to the severity and clinical outcomes of ischemic stroke. Patients with winter onset had more severe neurological deficits and worse outcomes than those with summer onset.

Mechanical Thrombectomy Up to 24 Hours in Large Vessel Occlusions and Infarct Velocity Assessment

Background

We retrospectively compared early‐ (<6 hours) versus late‐ (6–24 hours) presenting patients using perfusion‐weighted imaging selection and evaluated clinical/radiographic outcomes.

Methods and Results

Large vessel occlusion patients treated with mechanical thrombectomy from August 2017 to July 2020 within 24 hours of onset were retrieved from a single‐center database. Perfusion‐weighted imaging was analyzed by automated software and final infarct volume was measured semi‐automatically within 14 days. The primary end point was good outcome (modified Rankin Scale 0–2 at 90 days). Secondary end points were excellent outcome (modified Rankin Scale 0–1 at 90 days), symptomatic intracranial hemorrhage, and death. Clinical characteristics/radiological values including hypoperfusion volume and infarct growth velocity (baseline volume/onset‐to‐image time) were compared between the groups. Of 1294 patients, 118 patients were included. The median age was 74 years, baseline National Institutes of Health Stroke Scale score was 14, and core volume was 13 mL. The late‐presenting group had more female patients (67% versus 31%, respectively; P=0.001). No statistically significant differences were seen in good outcome (42% versus 53%, respectively; P=0.30), excellent outcome (26% versus 32%, respectively; P=0.51), symptomatic intracranial hemorrhage (6.5% versus 4.6%, respectively; P=0.74), and death (3.2% versus 5.7%, respectively; P=0.58) between the groups. The late‐presenting group had more atherothrombotic cerebral infarction (19% versus 6%, respectively; P=0.03), smaller hypoperfusion volume (median: 77 versus 133 mL, respectively; P=0.04), and slower infarct growth velocity (median: 0.6 versus 5.1 mL/h, respectively; P=0.03).

Conclusions

Patients with early‐ and late‐time windows treated with mechanical thrombectomy by automated perfusion‐weighted imaging selection have similar outcomes, comparable with those in randomized trials, but different in infarct growth velocities.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02251665.

Seasonal Variation in Incidence of Stroke in a General Population of 1.4 Million Japanese: The Shiga Stroke Registry

INTRODUCTION

The purpose of this study was to investigate seasonal variation in stroke incidence using data from a large-scale stroke registry of general population in current Japan.

METHODS

Shiga Stroke Registry (SSR) is an ongoing population-based registry of stroke that occurred in the Shiga Prefecture in central Honshu, Japan. A total 6,688 cases of first-ever stroke, with onset dates ranging from 1 January 2011 to 31 December in 2013 were included in this study. Incidence rates of first-ever stroke in each season were estimated using the person-year approach and adjusted for age and sex using the Poisson regression models.

RESULTS

From 2011 to 2013, we identified a total of 6,688 stroke cases (3,570 men, 3,118 women), of which 4,480 cases had ischemic stroke (2,518 men, 1,962 women), 1,588 had intracerebral hemorrhage (857 men, 731 women) and 563 had subarachnoid hemorrhage (166 men, 397 women). Age- and sex-adjusted incidence rates of total stroke were 151 (95% confidence interval [CI] 144-160, p = <0.001 vs. summer) in spring, 130 (95% CI 122-137) in summer, 141 (95% CI 133-149, p = 0.020 vs. summer) in autumn and 170 (95% CI 161-179, p = <0.001 vs. summer) in winter. Seasonal variation was more pronounced in intracerebral hemorrhage than in ischemic stroke.

CONCLUSION

In the present large-scale stroke registry of general population, incidence rates of stroke were highest in winter and lowest in summer in current Japan.

Blind Exchange With Mini-Pinning Technique Using the Tron Stent Retriever for Middle Cerebral Artery M2 Occlusion Thrombectomy in Acute Ischemic Stroke

Introduction: The usefulness of the blind exchange with mini-pinning (BEMP) technique has recently been reported for mechanical thrombectomy in patients with stroke owing to medium vessel occlusion (MeVO). The Tron stent retriever can be delivered and deployed through a 0.0165-inch microcatheter. This retriever has potential as an effective and safe treatment for acute ischemic stroke (AIS) due to occlusion of the M2 segment of the middle cerebral artery (MCA). Here, we report the outcomes of the BEMP technique using Tron stent retrievers for M2 occlusion thrombectomy.

Methods: Consecutive patients with AIS owing to M2 occlusion who underwent the BEMP technique using 2 × 15-mm or 4 × 20-mm Tron stent retrievers were included. The technique involves deploying a Tron stent retriever through a 0.0165-inch microcatheter, followed by microcatheter removal and blind navigation of a 3MAX or 4MAX aspiration catheter over the bare Tron delivery wire until the aspiration catheter reaches the clot. A Tron stent retriever is inserted into the aspiration catheter like a cork and subsequently pulled as a unit. We assessed procedural outcomes [first-pass expanded thrombolysis in cerebral infarction (eTICI) score 2c/3 and 2b/2c/3], safety outcomes [symptomatic intracranial hemorrhage (sICH)], and clinical outcomes (good outcome rate defined as modified Rankin Scale score 0–2 at 90 days and mortality at 90 days).

Results: Eighteen M2 vessels were treated in 15 patients (six female, median age: 80 years, and median National Institutes of Health Stroke Scale score: 18). The BEMP technique was performed successfully in all cases. Whether to use a 3MAX or 4MAX catheter was determined by considering one of the following target vessels: dominant, non-dominant, or co-dominant M2 (3MAX, n = 9; 4MAX, n = 9). The first-pass eTICI 2c/3 and 2b/2c/3 rates were 47 (7/15) and 60% (9/15), respectively; sICH was not observed. Seven patients (47%) achieved good outcomes, and one patient (7%) died within 90 days.

Conclusions: The Tron stent retriever was safely and effectively used in the BEMP technique for acute MCA M2 occlusion and can be combined with a 0.0165-inch microcatheter, which may be useful for treating MeVO, in general.

Dependence of seasonal dynamics of hemorrhagic and ischemic strokes on the climate of a region: A meta-analysis

BACKGROUND

Cardiovascular events occur more often in winter than in summer; however, the dependence of strokes on various meteorological factors remains unclear.

AIMS

The purpose of this meta-analysis was to determine the dependence of the circannual dynamics of hospitalizations for hemorrhagic stroke and ischemic stroke on seasonal fluctuations in meteorological factors.

SUMMARY OF REVIEW AND CONCLUSIONS

For our meta-analysis, we selected 20 and 26 publications examining the seasonal dynamics of hemorrhagic stroke and ischemic stroke, respectively . The meta-analysis showed that hemorrhagic stroke is less likely to occur in summer than in other seasons and does not depend on a region's climate. The seasonal dynamics of ischemic stroke are not clearly expressed and are determined by the characteristics of a region's climate. In a climate without pronounced seasonal dynamics of atmospheric pressure and in wet winters, the vector of ischemic stroke incidents will not be expressed or slightly shifted toward winter. Low atmospheric pressure in summer is associated with an increased likelihood of ischemic stroke during this season compared to winter. There was also a relation between ischemic stroke risk with high relative humidity and a significant decrease in ρO₂ in summer, but there is not enough evidence regarding this association. We did not reveal dependence of the seasonal dynamics of strokes on the amplitude of annual fluctuations in air temperature.

Ischaemic stroke in the time of coronavirus disease 2019

BACKGROUND AND PURPOSE

Stroke assistance is facing changes and new challenges since COVID-19 became pandemic. A variation on the patient influx might be one of the greater concerns, due to fewer people coming to emergency departments or coming too late. However, no data quantifying this have been published until now. The aim was to analyse the impact of the COVID-19 epidemic outbreak on hospital stroke admissions and their characteristics in our region.

METHODS

The data of every patient admitted to any hospital of our healthcare system with a diagnosis of ischaemic stroke between 30 December 2019 and 19 April 2020 were reviewed. Demographic and clinical data were recorded and compared between periods before and after the setting of the state of emergency secondary to the COVID-19 outbreak.

RESULTS

In total, 354 patients with ischaemic stroke were admitted in our study period. There was a weekly average of 27.5 cases before the setting of the state of emergency against 12 afterwards (P < 0.001). This drop in stroke cases occurred progressively from week 11, persisting in time despite the decrease in confirmed cases of COVID-19. No differences in the proportion of intravenous thrombolysis (21.1% vs. 21.5%, P = 0.935) or endovascular therapy (12.4% vs. 15.2%, P = 0.510) were found, nor in other demographic or clinical characteristics except for median onset-to-door time (102 vs. 183 min, P = 0.015).

CONCLUSIONS

This observational study offers the perspective of a whole region in one of the countries more heavily stricken by the SARS-CoV-2 epidemic and shows that the decrease of stroke events, since the beginning of the COVID-19 outbreak, happened globally and without any specific patient distribution.

Does the "Weekend Effect" Extend to Friday Admissions? An Analysis of Ischemic Stroke Hospitalizations in South Carolina

Background: Weekend admission has been found to be associated with higher hospital mortality and longer hospital stay among patients with acute cardiovascular conditions. Whether those admitted on Fridays face similar risk as those admitted on Sundays and Saturdays remain uncertain. Methods: This study used 2012-2013 data from hospital records for nonfatal patients with ischemic stroke in the state of South Carolina. The database contained the records of all hospitalizations in South Carolina except military and federal institutions. Multilevel logistic, negative binomial, and log-linear regression models were performed to explore the temporal pattern by hospital admission on specific day of a week for three outcomes: discharge to hospice care (vs. other alive discharges), length of stay, and total charge, respectively. Each model controlled for the patient age, gender, race/ethnicity, year of hospital admission, season of admission, payer, and Charlson Comorbidity Index. Results: A total of 19,346 nonfatal ischemic stroke hospitalizations were identified. Multilevel logistic regression shows that patients admitted on non-Friday weekdays had a significantly lower odds of being discharged to hospice care as compared with those admitted on Fridays [odds ratio = 0.80, 95% confidence interval (CI) = 0.65-0.99] where there was no significant difference between Friday admissions and weekend admissions. The length of hospital stay for admission on non-Friday weekdays was significantly shorter than that of Friday admissions [incident rate ratio (IRR) = 0.87, 95% CI = 0.84-0.90], whereas longer length of hospital stay was found on weekend admission (IRR = 1.06, 95% CI = 1.02-1.11). Friday admissions were not associated with higher charges as compared with non-Friday weekday admissions. Conclusions: Some hospitalization outcomes admitted on Fridays seemed to have the "weekend effects" too. Further studies are warranted to investigate underlying mechanism for such a difference in outcomes between Friday and other weekdays. Interventions to close the weekend-weekday gap of patient outcomes need to consider the elevated risk on Friday admission.

Use of Diffusion-Weighted Imaging-Alberta Stroke Program Early Computed Tomography Score (DWI-ASPECTS) and Ischemic Core Volume to Determine the Malignant Profile in Acute Stroke

Background Malignant profiles were identified by imaging profiles and unfavorable outcomes that have poor response to reperfusion therapy. Many trials have used this profile in their inclusion criteria including large-vessel occlusion acute ischemic stroke trials. We aimed to redefine the cutoff values for malignant profile in acute ischemic stroke patients with large-vessel occlusion regardless of reperfusion therapy. Methods and Results Consecutive acute ischemic stroke patients with anterior large-vessel occlusion were prospectively extracted from the National Cerebral and Cardiovascular Center Stroke Registry between March 2014 and December 2017. Diffusion-Weighted Imaging-Alberta Stroke Program Early Computed Tomography Score (DWI-ASPECTS) and diffusion-weighted imaging lesion ischemic core volume (VolDWI) were measured in acute ischemic stroke patients with large-vessel occlusion with or without treatment. Unfavorable outcome was defined as a modified Rankin Scale score 5 to 6 at 3 months, and optimal DWI-ASPECTS and VolDWI for unfavorable outcome were assessed. In total, 198 patients (111 men, 77±13 years old) were enrolled. Median DWI-ASPECTS was 7 (5-9), and median VolDWI was 55 (6-134) mL. Among the patients, 72 (36%) patients underwent reperfusion therapy, and 83 (42%) had unfavorable outcomes. The threshold values for a malignant profile on receiver operating characteristic curve analysis for DWI-ASPECTS and VolDWI were 4 (area under the curve 0.78, P<0.01; sensitivity 0.71, specificity 0.75) and 71 mL (area under the curve 0.80, P<0.01; sensitivity 0.76, specificity 0.77), respectively. Conclusions The cutoff values for our redefined malignant profile were DWI-ASPECTS 4 and VolDWI 71 mL with no selection bias for reperfusion therapy in the real-world clinical practice. Clinical Trial Registration URL: http://www.clinicaltrials.gov Unique identifier: NCT02251665.

Detection of Stenosis Progression in Intracranial Vertebral Artery Dissection Using Carotid Ultrasonography

BACKGROUND

The purpose of this study was to assess whether carotid ultrasonography indices detect arterial stenosis progression in patients with vertebral artery (VA) dissection.

METHODS

This was a retrospective, single-center, observational study that enrolled patients with intracranial VA dissection who were admitted from January 2011 to June 2017. Magnetic resonance angiography (MRA) was done on admission and followed up at a median 20 days after onset (interquartile range [IQR] 9-58 days), and ultrasonography was performed at a median of 22 (interquartile range 7-56) days. Peak systolic velocity (PSV), end-diastolic velocity (EDV), mean velocity (MV), and pulsatility index (PI) were measured by ultrasonography, and the ratio of each follow-up value to the baseline (follow-up/baseline) value was calculated. Two stroke neurologists categorized into 3 groups by morphological changes of the dissected vessel: patients with stenosis progression (progression group: P-group); those with no remarkable change or dilatation improved (stable group: S-group); and those with stenosis regression or dilatation enlargement (enlargement group: E-group). Ultrasonography indices were compared among the groups.

RESULTS

Of the 42 patients who were enrolled to this study, 39 patients underwent ultrasonography and MRA on both admission and follow-up. The PI ratio was significantly higher in the P-group than in the S-group (1.96 ± .80 versus .98 ± .44, P = .02) and in the E-group (versus .65 ± .35, P < .01). There were no significant differences in the PSV ratio, EDV ratio, and MV ratio.

CONCLUSIONS

In patients with VA dissection, the PI ratio on ultrasonography is a promising index to detect stenosis progression.

Consensus Guides on Stroke Thrombolysis for Anticoagulated Patients from Japan: Application to Other Populations

Development of direct oral anticoagulants and their antidotes has led to the need to reconsider the eligibility of acute stroke patients who have been taking oral anticoagulants for intravenous thrombolysis. Officially authorized Japanese guidelines on this issue were revised twice at the time of approval for clinical use of direct oral anticoagulants and idarucizumab, a specific reversal agent for dabigatran. A unique recommendation in the latest Japanese clinical guides was that thrombolysis can be recommended if the time of the last dose of direct oral anticoagulants exceeds 4 hours and if commonly available anticoagulation markers are normal or subnormal, i.e., international normalized ratio of prothrombin time <1.7 and activated partial thromboplastin time <1.5 times the baseline value (≤40 seconds only as a guide). These criteria are partly supported by the findings of domestic multicenter and single-center surveys that symptomatic or asymptomatic intracranial hemorrhage following thrombolysis was rare under the conditions of the criteria. Even for dabigatran users, stroke thrombolysis can be considered without pretreatment by idarucizumab if patients meet the above criteria. If not, direct mechanical thrombectomy can be considered without pretreatment by idarucizumab or thrombolysis, and use of idarucizumab, followed immediately by thrombolysis, can be considered only when thrombectomy cannot be quickly performed. These clinical guides are practical and to some extent economical, but they have some limitations, including lack of corroborating information from sufficient numbers of relevant cases. The guides will be further modified based on the results of future research.