Meteorological Factors and Seasonal Stroke Rates: A Four-year Comprehensive Study

Influence of Meteorological Parameters on the Prevalence of TEE Detected Left Atrial Appendage Thrombi

(1) Background: Meteorological factors seem to exert various effects on human health, influencing the occurrence of diseases such as thromboembolic events and strokes. Low atmospheric pressure in summer may be associated with an increased likelihood of ischemic stroke. The aim of this study was to investigate the potential impact of meteorological conditions on left atrial appendage (LAA) thrombus formation. (2) Methods: A total of 131 patients were included, diagnosed with a first instance of thrombus via 3D transesophageal echocardiography (TEE) between February 2009 and February 2019. Months with frequent thrombus diagnoses of at least 10 thrombi per month were categorized as frequent months (F-months), while months with fewer than 10 thrombus diagnoses per month were labelled as non-frequent months (N-months). The analysis focused on differences in meteorological parameters in two-week and four-week periods before the diagnosis. (3) Results: F-months were predominantly observed in spring and summer (April, May, June, and July), as well as in February and November. During F-months, a higher absolute temperature difference, lower relative humidity, longer daily sunshine duration, and greater wind speed maximum were observed in the two- and four-week periods rather than for N-months. In the two-week period, average temperatures, equivalent temperatures, and temperature maxima were also significantly higher during F-months than N-months. (4) Conclusion: Thrombi in the left atrial appendage are more prevalent during periods characterized by high absolute temperature differences, low relative humidity, and long daily sunshine duration.

Age-dependent seasonality in the incidence of stroke: A 21-year population-based study

INTRODUCTION

Seasonality in the incidence of stroke has been examined in numerous studies, yet data on whether it differs with age are limited. To fill this gap, we utilized a largescale dataset from Israel.

PATIENTS AND METHODS

We retrieved data of all hospitalizations for ischemic stroke (IS), transient ischemic attack (TIA) and intra cerebral hemorrhage (ICH) from 2000 to 2020. We maintained separate datasets for IS/TIA and ICH, divided into five age groups: 18-49, 50-59, 60-69, 70-79, and 80+. We modeled the monthly incidence using a generalized additive model. The seasonal effect was defined by the rate ratio (RR) of each month compared to the annual mean.

RESULTS

The analysis included 317,586 and 23,789 events of IS/TIA and ICH respectively. We found an interaction between age and seasonality, accounting for a phase shift with age in the seasonal pattern of IS/TIA incidence. For cases under 70 years, the peak was during summertime and the RRs increased with decreasing age, reaching 1.11 (95% CI 1.09-1.13) at the youngest age group. In contrast, among the elderly, a winter peak was observed and the RRs increased with age to 1.07 (95% CI 1.06-1.08) at the oldest age group. For ICH, a winter/autumn peak was identified and the RRs increased with age to 1.20 (95% CI 1.16-1.24).

CONCLUSIONS

Our finding of age-dependent seasonal patterns in the occurrence of stroke, suggests closer monitoring of cardiovascular risk factors during wintertime among elderly individuals. The mechanism governing the seasonal phase shift with age in IS/TIA incidence, requires further investigation.

Time of the day and season distribution among stroke code subtypes: differences between ischemic stroke, intracranial hemorrhage, and stroke mimic

Background

Circadian variations in the timing of the onset of stroke symptoms have been described, showing a morning excess of cardiovascular risk. To date, no differences have been found between stroke subtype and time distribution throughout the day. The present study aims to compare the seasonal and circadian rhythm of symptoms onset in ischemic, hemorrhagic, and stroke mimic patients.

Methods

This study was conducted prospectively at a hospital and involved a cohort of stroke alert patients from 2018 to 2021. Stroke subtypes were classified as ischemic stroke, intracerebral hemorrhage (ICH), transient ischemic attack (TIA), and stroke mimic. Clinical variables were recorded, and each patient was assigned to a 4-h interval of the day according to the time of onset of symptoms; unwitnessed stroke patients were analyzed separately. Seasonal changes in stroke distribution were analyzed at 3-month intervals.

Results

A total of 2,348 patients were included in this analysis (ischemic 67%, ICH 13%, mimic 16%, and TIA 3%). Regardless of stroke subtype, most of the patients were distributed between 08-12 h and 12-16 h. Significant differences were found in the time distribution depending on stroke subtype, with ICH predominating in the 4-8 h period (dawn), most of which were hypertensive, TIA in the 12-16 h period (afternoon), and stroke mimic in the 20 h period (evening). The ischemic stroke was evenly distributed throughout the different periods of the day. There were no differences in the seasonal pattern between different stroke subtypes, with winter being the one that accumulated the most cases.

Conclusion

The present study showed different circadian patterns of stroke subtypes, with a predominance of ICH at dawn and stroke mimic in the afternoon. The stroke circadian rhythm resembles previous studies, with a higher incidence in the morning and a second peak in the afternoon.

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.

The onset of cerebral infarction may be affected by differences in atmospheric pressure distribution patterns

Background

Some papers have highlighted a possible causal relationship between the onset of ischemic stroke and weather conditions. This study aimed to elucidate the onset mechanism of cerebral infarction from a meteorological approach. We focused on the atmospheric pressure distribution patterns (APDPs).

Methods

The subjects are 221 cases diagnosed as cardiogenic cerebral embolism (Group A) and 612 cases diagnosed as atherosclerotic cerebral thrombosis (Group B). We investigated the APDP on the date closest to the date and time of onset of cerebral infarction in each patient on the website and chose the most similar one from the reported 11 APDPs. Groups A and B were compared for clinical characteristics and the appearance rate of each APDP in each group.

Results

The clinical characteristics of Groups A and B were consistent with some previously reported clinical characteristics of cerebral embolism and cerebral thrombosis except for smoking. The appearance rate of the other high-pressure type, which cannot be classified as either the anticyclone belt type or the migratory anticyclone type, in Group B was statistically significantly higher than that in Group A, and the appearance rate of the anticyclone belt type in Group A was statistically significantly higher than that in Group B (p < 0.05, Fisher's exact probability method, respectively).

Conclusions

Cerebral embolism and cerebral thrombosis exhibited significant differences in APDPs on the day of onset. Dehydration particularly in the other high-pressure type or in the anticyclone belt type should be prevented. Further investigation should focus on the other meteorological factors.

The Impact of Weather and Mode of Transport on Outcomes of Patients With Acute Ischemic Stroke Undergoing Mechanical Thrombectomy

BACKGROUND

Efficient transfer to mechanical thrombectomy (MT)-capable centers is essential for patients with stroke. Weather may influence stroke risk, transportation, and outcomes.

OBJECTIVE

To investigate how weather affects stroke patient transfer and outcomes after MT.

METHODS

We retrospectively collected data for patients with stroke transferred from spoke to our hub hospital to undergo MT between 2017 and 2021. We examined associations between weather, transportation, and patient outcomes.

RESULTS

We included 543 patients with a mean age of 71.7 years. The median National Institutes of Health Stroke Score increased from 14 to 15 after transportation. The median modified Rankin Scale was 4 at discharge and 90 days, and 3 at the final follow-up (mean 91.7 days). Higher daily temperatures were associated with good outcome, whereas daily drizzle was associated with poor outcome. More patients were transferred by air when visibility was better, and by ground during heavier precipitation, higher humidity, rain, mist, and daily drizzle, fog, and thunder . Patient outcomes were not associated with transportation mode. Among the independent predictors of good outcome, none was a weather variable. Lower hourly relative humidity ( P = .003) and longer road distance ( P < .001) were independent predictors of using air transportation, among others.

CONCLUSION

During transportation, higher temperature was associated with good outcome, whereas daily drizzle was associated with poor outcome after MT. Although weather was associated with transportation mode, no differences in outcomes were found between transportation modes. Further studies are needed to modify transfer protocols, especially during cold and rainy days, and potentially improve outcomes.

The effects of combined early oral health care and early mobilisation on the incidence of stroke-associated pneumonia

OBJECTIVE

To investigate the effects of combined early oral healthcare and early mobilisation on the incidence of stroke-associated pneumonia during hospitalisation of acute stroke patients.

MATERIALS AND METHODS

In this single-centre, non-blinded, before-and-after cohort study, patients received basic stroke rehabilitation by a multidisciplinary team within 72 h of symptom onset from July to September 2016 and from July to September 2018. Patients were divided into two groups: 1) patients who received combined early oral healthcare and early mobilisation (early intervention group) (n=107), and 2) patients who received usual care (control group) (n=107). The relationship between the stroke-associated pneumonia incidence and prognosis was examined.

RESULTS

The early intervention group had a significantly lower incidence of stroke-associated pneumonia than the control group (0.93% vs. 7.48%; P=0.01). Moreover, the early intervention group had a significantly lower proportion of patients who died or required medical care because of recurrent pneumonia at discharge (0.93% vs. 5.6%; P=0.04). In contrast, there were no significant differences between the two groups regarding the Revised Hasegawa's Dementia Scale on day 14 (22.5 vs. 23; P=0.87), Functional Independence Measure on day 14 (112 vs. 116; P=0.06), and rate of total oral diet (Food Intake LEVEL Scale ≥7) at discharge (95.2% vs. 93.5%; P=0.55).

CONCLUSIONS

Combined early oral healthcare and early mobilisation by a multidisciplinary team significantly decreased the stroke-associated pneumonia incidence within 7 days and reduced the percentage of patients who died or required medical care because of recurrent pneumonia after stroke.

Effect of ambient temperature and other environmental factors on stroke emergency department visits in Beijing: A distributed lag non-linear model

Background

Most studies have focused on the relationship between ambient temperature and stroke mortality, but studies on the relationship between ambient temperature and stroke occurrence are still limited and inconsistent.

Objective

This study aimed to analyze the effect of ambient temperature and other environmental factors on emergency stroke visits in Beijing.

Methods

Our study utilized stroke visit data from the Beijing Red Cross Emergency Medical Center during 2017-2018, and applied a generalized additive model (GAM) as well as a distributed lag non-linear model (DLNM), respectively, regarding the direct, lagged, and cumulative effects of ambient temperature alone and with correction for other environmental factors on stroke occurrence.

Results

With a total of 26,984 emergency stroke patients in 2017-2018, both cold and hot effects were observed and weakened after correction for other environmental factors. Compared to the reference temperature, in the multi-factor model, extreme cold (-10°C) reached a maximum relative risk (RR) of 1.20 [95% Confidence Interval (CI): 1.09, 1.32] at lag 14 days, and extreme hot (30°C) had a maximum RR of 1.07 (95% CI: 1.04, 1.11) at lag 6 days. The cumulative effect of extreme cold reached a maximum of 2.02 (95% CI: 1.11, 3.67) at lag 0-14 days, whereas the cumulative effect of extreme hot temperature is greatest at lag 0-10 days, but no statistically significant effect was found. In addition, ischemic stroke patients, the elderly, and males were more susceptible to the effects of cold temperature.

Conclusions

There is a non-linear relationship between ambient temperature and stroke occurrence, with cold temperature having a greater and longer-lasting impact than hot temperature.

Association between reported work in cold environments and stroke occurrence in the CONSTANCES cohort: a prospective study

OBJECTIVE

Cold environments are a potential risk factor for stroke. The aim of this study was to investigate the association between performing work tasks in cold environments and the occurrence of a first stroke event.

METHODS

From the French population-based cohort CONSTANCES ('Cohorte des consultants des Centres d'examens de santé' in French), we collected data from baseline questionnaires along with medical interviews on cardiovascular risk factors and reported exposure to cold temperatures (<10°C) at work. Exposures were categorised as rare (<2 hours/day), often (≥2 and <4 hours/day) and almost always (≥4 hours/day). Incidence of stroke was retrieved from the French National Health database. Bivariate and multivariable logistic regression models were used to assess the association between working in cold environments and the incidence of stroke. Stratified analyses on stroke types were also conducted.

RESULTS

There were 160 782 participants and 224 strokes (168 ischaemic and 76 haemorrhagic) included in our study. No significant increase in stroke was found for working in cold environments; the adjusted OR for often or almost always exposed was 1.14 (95% CI 0.46 to 2.84).

CONCLUSIONS

This study did not reveal a significant excess risk of stroke for occupational exposures to low temperatures. Further studies are needed to better assess the effect of preventive measures and very low temperature on occurrence of cardiovascular diseases.

Associations between ambient air pollution, meteorology, and daily hospital admissions for ischemic stroke: a time-stratified case-crossover study in Beijing

Air pollution and ischemic stroke (IS) are both vital factors affecting the health of Beijing citizens. This study aims at exploring the associations between air pollution, meteorology, and the hospital admission of IS (IS HA). Information on 476,659 IS inpatients in secondary and higher hospitals in Beijing from 2013 to 2018 were collected. A time-stratified case-crossover design with the generalized additive model and the distributed lag nonlinear model were used. In the single-pollutant models, an inter-quartile range increase in O_3, SO₂, CO, and NO₂ resulted in a significant highest increase in IS HA by 2.23% (95% CI: 1.56%, 2.90%), 1.53% (95% CI: 1.12%, 1.95%), 1.05% (95% CI: 0.70%, 1.40%), and 0.51% (95% CI: 0.24%, 0.79%) on the day of pollution, so did PM_2.5 and PM₁₀ by 1.13% (95% CI: 0.68%, 1.59%) and 1.19% (95% CI: 0.74%, 1.64%) at a lag of 0-5 days. There was a nonlinear relationship between meteorology and IS HA. In the multivariate model, the cumulative relative risks with a maximum lag time of 21 days of PM_2.5 and NO₂ were 1.11 (95% CI: 1.04, 1.19) and 0.88 (95% CI: 0.82, 0.94), while the effects of SO₂, O₃, and meteorology were insignificant. The findings suggested that particulate pollutants could increase the risk of IS, and the elderly were more sensitive to it, while the results of gaseous pollutants are still discordant. The control of air pollution and the protection of susceptible populations should receive higher attention from policymakers.

Association of sunshine duration with acute myocardial infarction hospital admissions in Beijing, China: A time-series analysis within-summer

BACKGROUND

Over the years, various epidemiological studies found that acute myocardial infarction (AMI) often shows seasonal rhythm patterning, which is usually influenced by the variations of environmental factors, such as air pollution, ambient temperature, solar activity, relative humidity. However, there are few studies on the impact of sunlight-induced AMI especially in developing countries, and they had inconsistent results. This study aimed to examine within-summer variations in the temporal association between sun exposure and AMI.

METHODS

We obtained hospitalization data for AMI of Beijing during 2013-2019. We used a distributed lag non-linear model (DLNM) combined with a quasi-Poisson regression model to estimate the non-linear lag effects of sunshine duration on AMI incidences. We evaluated the overall effect of AMI admissions with exposure to sunshine duration in the lag 0-21 days.

RESULTS

A total of 45,301 AMI cases were enrolled in our study during summer (June-September). The minimum of the morbidity was during days with a sunshine duration of 3.9 h. We found significant and U-shaped associations between sunshine duration and AMI, and the overall estimated relative risk was 1.29 (95% CI: 1.02,1.62) and 1.69 (95% CI: 1.28,2.24) for short (1st percentile) and long (99th percentile) sunshine duration, respectively. The males and younger people (<65 years) were most susceptible to these effects.

CONCLUSION

Our results suggest that both short and long sunshine duration could increase the risk of AMI admissions, especially for males and younger people. We suggest that public health policymakers should fully consider the balance of the pros and cons of solar exposure, and provide appropriate public health recommendations accordingly to gain the greatest benefits from sunlight.

Investigating the association between temperature and hospital admissions for major psychiatric diseases: A study in Greece

Evidence has emerged regarding the role of seasonality and several meteorological parameters on bipolar disorder, schizophrenia and depression. We investigated the relationship between ambient and apparent temperature and hospital admissions of major psychiatric diseases in a psychiatric clinic of a General Hospital situated in Northern Greece during 2013-19. Temperature data was provided by the National Observatory of Athens and diagnosis for psychotic, schizophrenic, manic and bipolar and unipolar depression were retrieved from medical records. A total of 783 admissions were recorded. Poisson regression models adjusted for time trends were applied to analyze the impact of temperature on monthly admissions. A summer peak was observed for the bipolar disorder, irrespectively of substance/alcohol use status. Seasonality emerged also for psychotic and schizophrenic patients with a through in winter. An increase of 1 °C in either ambient or apparent temperature was associated with an increase 1-2% in the monthly admissions in most outcomes under investigation. Alcohol and drug abuse did not modify this effect. Although our results indicate effects of temperature on psychiatric admissions, they are not consistent across subgroups populations and need to be replicated by other methodologically superior studies.

The Influence of Selected Meteorological Factors on the Prevalence and Course of Stroke

Background: The objective of this study was to evaluate the impact of weather factors on stroke parameters. Methods: This retrospective study analyzed the records of stroke patients concerning the influence of meteorological conditions and moon phases on stroke parameters. Results: The study group consisted of 402 patients aged between 20 and 102; women constituted 49.8% of the subjects. Ischaemic stroke was diagnosed in 90.5% of patients and hemorrhagic stroke was diagnosed in 9.5% of patients. The highest number of hospitalizations due to stroke was observed in January (48 events); the lowest number was observed in July (23 events). There was no statistically significant correlation between the meteorological parameters on the day of onset and the preceding day of stroke and the neurological status (NIHSS) of patients. Mean air temperature on the day of stroke and the day preceding stroke was significantly lower in the group of patients discharged with a very good functional status (≤2 points in modified Rankin scale (mRS)) compared to the patients with a bad functional status (>2 points in mRS); respectively: 7.98 ± 8.01 vs. 9.63 ± 7.78; p = 0.041 and 8.13 ± 7.72 vs. 9.70 ± 7.50; p = 0.048). Humidity above 75% on the day of stroke was found to be a factor for excellent functional state (RR 1.61; p = 0.016). The total anterior circulation infarcts (in comparison with stroke in the other localization) were more frequent (70%) during a third quarter moon (p = 0.011). The following parameters had a significant influence on the number of stroke cases in relation to autumn having the lowest number of onsets: mean temperature (OR 1.019 95% CI 1.014–1.024, p < 0.000), humidity (OR 1.028, CI 1.023–1.034, p < 0.0001), wind speed (OR 0.923, 95% CI 0.909–0.937, p < 0.0001), insolation (OR 0.885, 95% CI 0.869–0.902, p < 0.0001), precipitation (OR 0.914, 95% CI 0.884–0.946, p < 0.0001). Conclusion: Air humidity and air temperature on the day of stroke onset as well as air temperature on the day preceding stroke are important for the functional status of patients in the acute disease period. A combination of the following meteorological parameters: lowered mean temperature and low sunshine, high humidity and high wind speed all increase the risk of stroke during the winter period. High humidity combined with high precipitation, low wind speed and low sunshine in the autumn period are associated with the lowest stroke incidence risk. A possible relationship between phases of the moon and the incidence requires further investigation.

Stroke Seasonality and Weather Association in a Middle East Country: A Single Tertiary Center Experience

Background: Stroke is a medical condition that leads to major disability and mortality worldwide. Some evidence suggests that weather and seasonal variations could have an impact on stroke incidence and outcome. However, the current evidence is inconclusive. Therefore, this study examines the seasonal variations and meteorological influences on stroke incidence and outcome in the largest city in Saudi Arabia.

Methods: From February 2016 to July 2019, we retrospectively reviewed data from all patients with acute ischemic (AIS) or hemorrhagic stroke (HS) admitted to the stroke unit in a tertiary academic center in Saudi Arabia. The corresponding daily meteorological data were obtained for the same period. We considered the months from November to March as the cold season and April to October as the hot season.

Results: The final cohort included 1,271 stroke patients; 60.89% (n = 774) cases occurred in the hot season, while 39.1% (n = 497) in the cold season. Males accounted for 69.6% (n = 884) of the cases. The proportion of ischemic stroke was 83.2% [hot season 83.9% (n = 649) vs. cold season 82.3% (n = 409)]. We found no statistically significant difference between seasons (hot or cold) in stroke incidence, severity [National Institutes of Health Stroke Scale (NIHSS)], hospital course (pneumonia, thromboembolism, intensive care stay, or length of stay), or outcome [modified Rankin scale (mRS) on discharge and death].

Conclusions: In Riyadh, Saudi Arabia, our study found no impact of weather or seasonal variations on stroke incidence, hospital course, or outcomes. However, our findings warrant further research in different country regions.

Differentiation between Stroke Subtypes and the Causes of Monthly Variations: The Akita Stroke Registry

Objective It has been established that stroke occurrence is influenced by seasonality. Stroke is divided into three subtypes: cerebral hemorrhage (CH), cerebral infarction (CI), and subarachnoid hemorrhage (SAH). The purpose of this paper was to analyze stroke events by subtype and month, in order to clarify the biggest factors that affect seasonal differences and thereby gain insight into stroke prevention. Methods Initial stroke events in the Akita Stroke Registry from 1991 to 2010 (58,684 cases; male 30,549, female 28,135) were classified by subtype and the month of onset, and correlations were estimated based on 115 healthy volunteers' monthly mean resting blood pressure (BP) at home and outdoor temperature measured by the Akita Meteorological Observatory in 2001. Results Systolic BP showed monthly variation in both morning and evening measurements. BP and outdoor temperature showed significant correlations with hemorrhagic stroke events by month (CH: r=0.87, r=-0.82; SAH: r=0.68, r=-0.82). Among the stroke subtypes, seasonal differences were the greatest in CH. Systolic BP was the most important factor for monthly and seasonal variation in stroke events. By comparing monthly BP variations with CH incidence throughout the year, we concluded that a decrease in home BP of 5 mmHg can reduce the risk of CH by 35%. Conclusion Our findings suggest that lowering BP would be the best strategy for CH prevention. Simple daily actions may be affected by cold stress. As physicians, we must strive to help patients lower their BP throughout the year not only with medication but with lifestyle guidance, especially in winter.

Global warming and neurological practice: systematic review

Background

Climate change, including global warming, will cause poorer global health and rising numbers of environmental refugees. As neurological disorders account for a major share of morbidity and mortality worldwide, global warming is also destined to alter neurological practice; however, to what extent and by which mechanisms is unknown. We aimed to collect information about the effects of ambient temperatures and human migration on the epidemiology and clinical manifestations of neurological disorders.

Methods

We searched PubMed and Scopus from 01/2000 to 12/2020 for human studies addressing the influence of ambient temperatures and human migration on Alzheimer’s and non-Alzheimer’s dementia, epilepsy, headache/migraine, multiple sclerosis, Parkinson’s disease, stroke, and tick-borne encephalitis (a model disease for neuroinfections). The protocol was pre-registered with PROSPERO (2020 CRD42020147543).

Results

Ninety-three studies met inclusion criteria, 84 of which reported on ambient temperatures and nine on migration. Overall, most temperature studies suggested a relationship between increasing temperatures and higher mortality and/or morbidity, whereas results were more ambiguous for migration studies. However, we were unable to identify a single adequately designed study addressing how global warming and human migration will change neurological practice. Still, extracted data indicated multiple ways by which these aspects might alter neurological morbidity and mortality soon.

Conclusion

Significant heterogeneity exists across studies with respect to methodology, outcome measures, confounders and study design, including lack of data from low-income countries, but the evidence so far suggests that climate change will affect the practice of all major neurological disorders in the near future. Adequately designed studies to address this issue are urgently needed, requiring concerted efforts from the entire neurological community.

Seasonal patterns and associations in the incidence of acute ischemic stroke requiring mechanical thrombectomy

Background

In order to identify risk periods with an increased demand in technical and human resources, we tried to determine patterns and associations in the incidence of acute ischemic stroke due to embolic large vessel occlusions (eLVO) requiring mechanical thrombectomy (MT).

Methods

We conducted a time series analysis over a 9‐year period (2010–2018) based on observational data in order to detect seasonal patterns in the incidence of MT due to eLVO (n = 2628 patients). In a series of sequential negative binominal regression models, we aimed to detect further associations (e.g., temperature, atmospheric pressure, air pollution).

Results

There was a 6‐month seasonal pattern in the incidence of MT due to eLVO (p = 0.024) peaking in March and September. Colder overall temperature was associated with an increase in MT due to eLVO (average marginal effect [AME], [95% CI]: −0.15 [−0.30–0.0001]; p = 0.05; per °C). A current increase in the average monthly temperature was associated with a higher incidence of MT due to eLVO (0.34 [0.11–0.56]; p = 0.003). Atmospheric pressure was positively correlated with MT due to eLVO (0.38 [0.13–0.64]; p = 0.003; per hectopascal [hPa]). We could detect no causal correlation between air pollutants and MT due to eLVO.

Conclusions

Our data suggest a 6‐month seasonal pattern in the incidence of MT due to eLVO peaking in spring and early autumn. This might be attributed to two different factors: (1) a current temperature rise (comparing the average monthly temperature in consecutive months) and (2) colder overall temperature. These results could help to identify risk periods requiring an adaptation in local infrastructure.

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.

Impact of COVID-19 pandemic on stroke admissions in Qatar

Introduction

The COVID-19 pandemic has resulted in a dramatic unexplained decline in hospital admissions due to acute coronary syndromes and stroke. Several theories have emerged aiming to explain this decline, mostly revolving around the fear of contracting the disease and thus avoiding hospital visits.

Aims

In this study, we aim to examine the impact of the COVID-19 pandemic on stroke admissions to a tertiary care centre in Qatar.

Methods

The Hamad General Hospital stroke database was interrogated for stroke admissions between September 2019 and May 2020. The number of stroke admissions, stroke subtypes and short-term outcomes was compared between the ‘pre-COVID-19’ period (September 2019 to February 2020) and the COVID-19 pandemic period (March to May 2020).

Results

We observed a significant decline in monthly admissions in March (157), April (128) and May (135) compared with the pre-COVID-19 6-month average (229) (p=0.024). The reduction in admissions was most evident in functional stroke mimics. The average admissions decreased from 87 to 34 per month (p=0.0001). Although there were no significant differences in admissions due to ischaemic stroke (IS), intracranial haemorrhage or transient ischaemic attacks between the two periods, we noted a relative decrease in IS due to small vessel disease and an increase in those due to large vessel atherosclerosis in March to May 2020.

Conclusions

The decline in overall stroke admissions during the COVID-19 pandemic is most likely related to concerns of contracting the infection, evidenced mainly by a decline in admissions of stroke mimics. However, a relative increase in large vessel occlusions raises suspicion of pathophysiological effects of the virus, and requires further investigation.