Characteristics of acute ischemic stroke in hospitalized patients in Tibet: a retrospective comparative study

Lu, Yuxuan; Zhuoga, Cidan; Jin, Haiqiang; Zhu, Feiqi; Zhao, Yanxin; Ding, Zhijie; He, Shihua; Du, Ailian; Xu, Jun; Luo, Jingjing; Sun, Ying

doi:10.1186/s12883-020-01957-0

Cited by 11 publications

(10 citation statements)

References 23 publications

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“…This protective effect is stronger if the altitudes range from 2,000 to 3,500 m while residing above 3,500 m may be associated with an increased risk of developing stroke. It is consistent with the high stroke incidence reported in the epidemiological data of Tibet ( 13 ), as most of its cities or towns are located above 3,500 m. However, in this study, we found that this protection seems to be effective for lacunar infarction still, even when the patients reside at a very high altitude (Tibet). Angiogenesis or capillary remodeling in the brain may be the key reasons.…”

Section: Discussionsupporting

confidence: 92%

Cerebral small-vessel disease at high altitude: A comparison of patients from plateau and plain

Shu

Wen²,

Zhang³

et al. 2023

Front. Neurol.

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Background and purposeCerebral small-vessel disease (CSVD) is prevalent worldwide and one of the major causes of stroke and dementia. For patients with CSVD at high altitude, a special environmental status, limited information is known about their clinical phenotype and specific neuroimaging change. We investigated the clinical and neuroimaging features of patients residing at high altitude by comparing with those in the plain, trying to explore the impact of high altitude environment on CSVD.MethodsTwo cohorts of CSVD patients from the Tibet Autonomous Region and Beijing were recruited retrospectively. In addition to the collection of clinical diagnoses, demographic information and traditional vascular risk factors, the presence, location, and severity of lacunes and white matter hyperintensities were assessed by manual counting and using age-related white matter changes (ARWMC) rating scale. Differences between the two groups and influence of long-term residing in the plateau were analyzed.ResultsA total of 169 patients in Tibet (high altitude) and 310 patients in Beijing (low altitude) were enrolled. Fewer patients in high altitude group were found with acute cerebrovascular events and concomitant traditional vascular risk factors. The median (quartiles) ARWMC score was 10 (4, 15) in high altitude group and 6 (3, 12) in low altitude group. Less lacunes were detected in high altitude group [0 (0, 4)] than in low altitude group [2 (0, 5)]. In both groups, most lesions located in the subcortical (especially frontal) and basal ganglia regions. Logistic regressions showed that age, hypertension, family history of stroke, and plateau resident were independently associated with severe white matter hyperintensities, while plateau resident was negatively correlated with lacunes.ConclusionPatients of CSVD residing at high altitude showed more severe WMH but less acute cerebrovascular events and lacunes in neuroimaging, comparing to patients residing at low altitude. Our findings suggest potential biphasic effect of high altitude on the occurrence and progression of CSVD.

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Section: Discussionsupporting

confidence: 92%

Cerebral small-vessel disease at high altitude: A comparison of patients from plateau and plain

Shu

Wen²,

Zhang³

et al. 2023

Front. Neurol.

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“…Study 12: A hospital-based comparative study in Tibet and Beijing with 236 and 1021 patients, respectively, with acute ischaemic stroke published by Lu et al in 2020 demonstrated that patients diagnosed with acute ischaemic stroke located at 3650 m (Tibet) above sea level were younger than those who lived at 40 m (Beijing) above sea level (p<0.001); also, in Tibet, there was a higher proportion of cerebrovascular accidents in young adults, which may be associated with erythrocytosis. 33 …”

Section: Resultsmentioning

confidence: 99%

“…Several anecdotal case reports and case series of people suffering from stroke-related disorders at high altitude have been published since the late 1800s 25. Despite this apparent relationship, very few well-conducted epidemiological studies have been conducted worldwide, and we have only included those studies that fulfilled our inclusion and exclusion criteria 14 15 20 21 26–36…”

Section: Resultsmentioning

confidence: 99%

Chronic high-altitude exposure and the epidemiology of ischaemic stroke: a systematic review

et al. 2022

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IntroductionAbout 5.7% of the world population resides above 1500 m. It has been hypothesised that acute exposure to high-altitude locations can increase stroke risk, while chronic hypoxia can reduce stroke-related mortality.ObjectiveThis review aims to provide an overview of the available evidence on the association between long-term high-altitude exposure and ischaemic stroke.DesignA systematic review was performed from 1 January 1960 to 1 December 2021 to assess the possible link between high-altitude exposure and ischaemic stroke. The AMED, EMBASE, Cochrane Library, PubMed, MEDLINE, the Europe PubMed Central and the Latin-American bibliographic database Scielo were accessed using the University of Southampton library tool Delphis. In this review, we included population and individual-based observational studies, including cross-sectional and longitudinal studies except for those merely descriptive individual-based case reports. Studies were limited to humans living or visiting high-altitude locations for at least 28 days as a cut-off point for chronic exposure.ResultsWe reviewed a total of 1890 abstracts retrieved during the first step of the literature review process. The authors acquired in full text as potentially relevant 204 studies. Only 17 documents met the inclusion criteria and were finally included. Ten studies clearly suggest that living at high altitudes may be associated with an increased risk of stroke; however, five studies suggest that altitude may act as a protective factor for the development of stroke, while two studies report ambiguous results.ConclusionsThis review suggests that the most robust studies are more likely to find that prolonged living at higher altitudes reduces the risk of developing stroke or dying from it. Increased irrigation due to angiogenesis and increased vascular perfusion might be the reason behind improved survival profiles among those living within this altitude range. In contrast, residing above 3500 m seems to be associated with an apparent increased risk of developing stroke, probably linked to the presence of polycythaemia and other associated factors such as increased blood viscosity.

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“…A higher prevalence of acute ischemic stroke (>anterior circulation) was reported in younger Tibetan (Tibet 3650 m) compared to Chinese lowlanders (Beijing 40 m) and the authors suggested that erythrocytosis and hyperhomocysteinemia possibly contribute to these differences. 48 Another retrospective study reported that the first-ever acute ischemic stroke in Tibetan plateau residents were more severe and showed a larger infarct volume and less artherosclerotic factors, suggesting a prevailing risk related to the hypercoagulable state due to polycythemia (reduced blood flow and increase peripheral resistance) and an increased hypoxia-inflammatory response at HA. 44 First ever ischemic stroke due to polycythemia induced by chronic HH (>4000 m) exposure have been reported in Indian soldiers more frequently at high compared to low altitude (13.7 vs 1.05/1000).…”

Section: Literature and Research Methodsmentioning

confidence: 99%

Recommendations for traveling to altitude with neurological disorders

Falla

Giardini²,

Angelini

2021

J Cent Nerv Syst Dis

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Background Several neurological conditions might worsen with the exposure to high altitude (HA). The aim of this review was to summarize the available knowledge on the neurological HA illnesses and the risk for people with neurological disorders to attend HA locations. Methods A search of literature was conducted for several neurological disorders in PubMed and other databases since 1970. The neurological conditions searched were migraine, different cerebrovascular disease, intracranial space occupying mass, multiple sclerosis, peripheral neuropathies, neuromuscular disorders, epileptic seizures, delirium, dementia, and Parkinson’s disease (PD). Results Attempts were made to classify the risk posed by each condition and to provide recommendations regarding medical evaluation and advice for or against traveling to altitude. Individual cases should be advised after careful examination and risk evaluation performed either in an outpatient mountain medicine service or by a physician with knowledge of HA risks. Preliminary diagnostic methods and anticipation of neurological complications are needed. Conclusions Our recommendations suggest absolute contraindications to HA exposure for the following neurological conditions: (1) Unstable conditions–such as recent strokes, (2) Diabetic neuropathy, (3) Transient ischemic attack in the last month, (4) Brain tumors, and 5. Neuromuscular disorders with a decrease of forced vital capacity >60%. We consider the following relative contraindications where decision has to be made case by case: (1) Epilepsy based on recurrence of seizure and stabilization with the therapy, (2) PD (± obstructive sleep apnea syndrome-OSAS), (3) Mild Cognitive Impairment (± OSAS), and (4) Patent foramen ovale and migraine have to be considered risk factors for acute mountain sickness.

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Characteristics of acute ischemic stroke in hospitalized patients in Tibet: a retrospective comparative study

Cited by 11 publications

References 23 publications

Cerebral small-vessel disease at high altitude: A comparison of patients from plateau and plain

Cerebral small-vessel disease at high altitude: A comparison of patients from plateau and plain

Chronic high-altitude exposure and the epidemiology of ischaemic stroke: a systematic review

Recommendations for traveling to altitude with neurological disorders

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