The term ‘stroke’ refers to a loss of blood supply to one or more areas of the brain1.
Because the brain is reliant on a continuous supply of oxygen and other nutrients, stroke can result in brain damage and various symptom manifestations, including cognitive deficits, depending on the precise regions affected.
The majority of strokes are due to the blockage of part of the brain’s blood supply (ischemic stroke), while others result from bleeding in/around the brain (haemorrhagic stroke). Transient ischaemic attack (TIA) refers to temporary loss of the brain’s blood supply, leading to symptoms that typically resolve within 24 hours.
Stroke can occur at any age but is more common with advancing age. The lifetime risk of having one or more strokes is 1:5 for women, and 1:10 for men2.
When there is persistent impairment in mental abilities due to stroke or other problems with blood supply to the brain, an individual may meet diagnostic criteria for vascular dementia. Vascular dementia is the second most common type of dementia across the world, after Alzheimer’s disease.
The global impact of cerebrovascular disease on quality of life, longer-term outcomes, and the economy is massive3.
In the World Health Organization Global Burden of Diseases survey, cerebrovascular disease was found to be the second leading global cause of death (second only to ischaemic heart disease), accounting for approximately 5.7 million deaths per annum4. The annual cost of strokes has been estimated at >$65 billion in the USA alone5,6.
Pathology and functional impact of Stroke and Cerebrovascular disease
Over 10,000 peer-reviewed manuscripts have been published regarding risk factors for cerebrovascular disease7.
One important mechanism underlying risk for cerebrovascular disease is higher than normal concentrations of low-density lipoprotein (LDL) cholesterol, which in turn alters arterial cell walls and triggers inflammatory responses that lead to plaque formation in arteries.
Risk factors implicated in one or more types of cerebrovascular disease include atrial fibrillation (an irregular heart rhythm), high blood pressure, diabetes, chronic obstructive pulmonary disease, sedentary lifestyle, obesity, and heavy smoking8,9.
Research and development in Stroke and Cerebrovascular disease
Whenever an individual is suspected of having a stroke or other cerebrovascular event, rapid assessment by a specialist team is vital along with consideration of treatment interventions.
Affected individuals should also receive regular follow-ups to monitor risk factors and provide multidisciplinary support to maximise recovery.
Assessment typically includes a clinical history, thorough physical examination (including neurological), blood tests (e.g. to measure lipid profiles and clotting), and (where indicated) imaging investigations. Examples of imaging investigations used in suspected new-onset cerebrovascular disease include carotid artery duplex (ultrasound), brain magnetic resonance imaging (MRI), and/or brain computed tomography (CT).
Treatments for brain bleeds (haemorrhagic stroke) focus on stopping the bleeding, and reducing risk of recurrence, such as insertion of a stent. Treatments for carotid artery disease focus on reducing the risk of emboli, and may include use of antiplatelet medication, and/or carotid endarterectomy.
Cerebrovascular disease is associated with neuropsychological impairment, due to underlying damage to brain regions responsible for distinct cognitive functions10.
Research has found that micro-infarcts in the cortex and subcortical regions are particularly strongly related to cognitive impairment11.
While modifiable risk factors can be targeted across the age span to reduce risk of developing vascular dementia and associated cognitive impairment, targeted evidence-based treatments for reversing cognitive impairment in established disease are lacking12.
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Barquera S., et al (2015). Global Overview of the Epidemiology of Atherosclerotic Cardiovascular Disease. Arch Med Res.
Seidel G.A., et al (2012). Cerebrovascular disease and cognition in older adults. Curr Top Behav Neurosci.
Barnett J.H., et al (2013). Cognitive health begins at conception: addressing dementia as a lifelong and preventable condition. BMC Med.
Mavaddat N., et al (1999). Cognition following subarachnoid haemorrhage from anterior communicating artery aneurysm: relation to timing of surgery. J Neurosurg.
Jaillard A., (2009). Hidden dysfunctioning in subacute stroke. Stroke.
- Stroke Association, 2015.
- Seshadri S, Wolf PA. Lifetime risk of stroke and dementia: current concepts, and estimates from the Framingham Study. Lancet Neurol. 2007 Dec;6(12):1106-14.
- The global burden of disease: 2004 update. World Health Organization, 2004.
- American Heart Association. Heart Disease and Stroke Statistics—2008 Update. Dallas, TX: American Heart Association; 2008.
- Barquera S, Pedroza-Tobías A, Medina C, Hernández-Barrera L, Bibbins-Domingo K, Lozano R, Moran AE. Global Overview of the Epidemiology of Atherosclerotic Cardiovascular Disease. Arch Med Res. 2015 Jul;46(5):328-38.
- Pubmed search conducted September 2015 using search terms “risk AND factors AND cerebrovascular”
- Arboix A. Cardiovascular risk factors for acute stroke: Risk profiles in the different subtypes of ischemic stroke. World J Clin Cases. 2015 May 16;3(5):418-29.
- Behrouz R, Powers CJ. Epidemiology of classical risk factors in stroke patients in the Middle East. Eur J Neurol. 2015 Jun 4.
- Seidel GA, Giovannetti T, Libon DJ. Cerebrovascular disease and cognition in older adults. Curr Top Behav Neurosci. 2012;10:213-41.
- Kalaria RN. Cerebrovascular disease and mechanisms of cognitive impairment: evidence from clinicopathological studies in humans. Stroke. 2012 Sep;43(9):2526-34.
- Barnett JH, Hachinski V, Blackwell AD. Cognitive health begins at conception: addressing dementia as a lifelong and preventable condition. BMC Med. 2013 Nov 19;11:246. doi: 10.1186/1741-7015-11-246.