Permanent death of neurons caused by inadecuate perfusion of a region of brain or brainstem.
This disturbance is due to either ischemia (lack of blood flow) or hemorrhage.
The term major stroke is used to distinguish a full-blown stroke from a minor stroke, or transient ischemic attack (TIA).
Stroke is the fourth killer and number one cause of adult disability in the United States. The estimated direct and indirect costs of stroke care in this country are $68.9 billion for 2009. The prevalence of stroke and its cost will undoubtedly rise as the aging population increases. In addition, stroke incidence and mortality are increasing in less developed countries in which the lifestyles and population restructuring are rapidly changing. More population-based research to assess incidence, risk factors, and outcomes are needed in these countries. Epidemiologic studies can help identify groups of individuals or regions at higher risk for stroke. They can also help us better understand the natural history of certain conditions and therefore push the direction of therapeutic investigations. Furthermore, the study of trends across different time periods and different populations can help investigators evaluate the effects of stroke care programs and treatment options 2).
Although the prevalence of stroke and its risk factors has been widely reported in some Western countries, information on essential stroke parameters is lacking in China, the most populous nation. A community-based cross-sectional study with 8,018 Chinese adults aged ≥40 years was used to determine the prevalence of stroke and associated risk factors. Within the screened population, the prevalence of stroke was 2.21% for both sexes, 1.60% for females, and 3.18% for males. Prevalence increased with age in both sexes (P < 0.0001). In a multivariable model, factors significantly associated with stroke were increasing age (odds ratio [OR] = 1.87, 95% CI: 1.58-2.24), male gender (OR = 2.03, 95% CI: 1.42-2.90), family history of stroke (OR = 4.33, 95% CI: 2.89-6.49), history of hyperlipidemia (OR = 1.87, 95% CI 1.31-2.68), history of hypertension (OR = 1.47, 95% CI 1.02-2.12), and physical inactivity (OR = 1.74, 95% CI: 1.16-2.59). The findings indicate that stroke prevalence in middle-aged and older Chinese adults is higher in males than in females, and increases with age in both sexes. Population-based public health intervention programs and policies targeting hyperlipidemia and hypertension control and encouragement of physical activity should be highly prioritized for middle-aged and older adults in Shenzhen, China 3).
Stroke etiology was classified as cardioembolism in 22 patients (59.4%), large-artery atherosclerosis in 8 (21.6%), and undetermined in 7 (18.9%). The clots from cardioembolism had a significantly higher proportion of red blood cells (37.8% versus 16.9%, P = .031) and a lower proportion of fibrin (32.3% versus 48.5%, P = .044) compared with those from large artery atherosclerosis. The proportion of red blood cells was significantly higher in clots with a susceptibility vessel sign than in those without it (48.0% versus 1.9%, P < .001), whereas the proportions of fibrin (26.4% versus 57.0%, P < .001) and platelets (22.6% versus 36.9%, P = .011) were significantly higher in clots without a susceptibility vessel sign than those with it.
The histologic composition of clots retrieved from cerebral arteries in patients with acute stroke differs between those with cardioembolism and large-artery atherosclerosis. In addition, a susceptibility vessel sign on gradient echo sequence is strongly associated with a high proportion of red blood cells and a low proportion of fibrin and platelets in retrieved clots 4).
There is conflicting evidence for whether or not the incidence of stroke is influenced by the daily temperature.
Pathophysiology and Neuroprotective Strategies in Hypoxic-Ischemic Brain Injury and Stroke 6).
see Stroke syndromes.
A rapid and reliable diagnostic test to distinguish ischemic from hemorrhagic stroke in patients presenting with stroke-like symptoms is essential to optimize management and triage for thrombolytic therapy.
Stroke has been extensively studied in clinical practice and experimental research by means of MR images with ever-emerging new technologies, such as DWI, PWI, and ADC maps. More recently, different PWI-derived parameters, such as the rCBV), the relative cerebral blood flow (rCBF), the relative MTT, and the time to peak (TTP) have been applied to quantify the perfusion deficit and to evaluate the temporal infarct growth in acute stroke either in patients or in small animals with high field strength MR spectrometers 7).
A bursting inflammation has been observed that compromises neurologic function in patients who experience stroke.
A common complication after stroke is development of cognitive impairment and dementia.
Stroke is deemed a worldwide leading cause of neurological disability and death.
Stroke causes life long disabilities where few therapeutic options are available. Using electrical and magnetic stimulation of the brain and physical rehabilitation, recovery of brain function can be enhanced even late after stroke.
see Stroke biomarker.
Effective strategies for reducing the risk of developing problems after stroke remain undefined. Potential strategies include intensive lowering of blood pressure (BP) and/or lipids.
Time is of the essence when diagnosing, and treating a stroke (brain attack) and restoring normal blood flow to the affected areas. The success and effectiveness of interventional stroke therapy literally depends on how quickly a patient recognizes the symptoms of stroke and seeks emergency medical care. Interdisciplinary in nature.
TeleStroke considerably improves quality of stroke care (for instance, by increasing thrombolysis) and may be valuable for the management of intracranial hemorrhages in rural hospitals and hospitals lacking neurosurgical departments, given that surgical/interventional therapy is only recommended for a subgroup of patients.
For ischemic strokes caused by blood clots, the medical team will first give clot-busting drugs, such as tPA (tissue plasminogen activator) intravenously to patients who arrive at the hospital within three hours from the onset of stroke symptoms. If the tPA does not adequately dissolve the clot or cannot be administered within the ideal timeframe, Northwestern’s neuroendovascular experts can offer intra-arterial (through the artery) thrombolysis treatment. This therapy helps extend the required treatment time for tPA up to six hours by delivering the clot-busting drug directly to the blockage. This intra-arterial procedure involves inserting, under x-ray guidance, a catheter (a thin tube) into the femoral artery located in the patient’s leg, near the groin area, and guiding it to the site of the clot. From there, the interventional neuroradiology team can locally administer a clot-busting agent to dissolve the blockage. The patient undergoes the entire procedure under general anesthesia.
Clots can also be broken up or removed via mechanical means. Using the same type of catheter-based technique as other intra-arterial therapies, Northwestern’s interventional neuroradiologists have at their disposal advanced clot-retrieving systems for the treatment of ischemic stroke. Inserted through the catheter, a tiny corkscrew-shaped device, called the MERCI, allows the neuroendovascular specialists to capture the clot and pull it free and away from the site of the blockage. This procedure can be used up to eight hours after the onset of stroke symptoms.
For Guideline see American Heart Association.
611 ischemic and 805 hemorrhagic stroke patients who were admitted within 24 h after the symptom onset. Data were analyzed with independent t test and Chi square test, and then with multivariate logistic regression analysis.
In ischemic stroke, National Institutes of Health Stroke Scale (NIHSS) score (OR 1.08; 95 % CI 1.06-1.11; P < 0.01), white blood cell count (OR 1.11; 95 % CI 1.05-1.18; P < 0.01), systolic blood pressure (BP) (OR 0.49; 95 % CI 0.26-0.90; P = 0.02) and age (OR 1.03; 95 % CI 1.00-1.05; P = 0.03) were associated with in-hospital mortality. In hemorrhagic stroke, NIHSS score (OR 1.12; 95 % CI 1.09-1.14; P < 0.01), systolic BP (OR 0.25; 95 % CI 0.15-0.41; P < 0.01), heart disease (OR 1.94; 95 % CI 1.11-3.39; P = 0.02) and creatinine (OR 1.16; 95 % CI 1.01-1.34; P = 0.04) were related to in-hospital mortality. Nomograms using these significant predictors were constructed for easy and quick evaluation of in-hospital mortality.
Variables in acute stroke can predict in-hospital mortality and help decision-making in clinical practice using nomogram 8).