Stroke Overview

Nearly 90% of strokes are ischemic, meaning that blood flow in the brain is blocked by an obstruction.¹ A smaller proportion of strokes are hemorrhagic. This type of stroke occurs when an artery ruptures and sends blood into the space between the brain and the arachnoid layer (subarachnoid hemorrhage) or into the brain itself (intracerebral hemorrhage).² Without steady blood flow, permanent brain damage can occur within minutes.³ Risk factors for stroke include hypertension, older age, dyslipidemia, diabetes, obesity, smoking, and a family history of strokes.⁴

The lifetime risk of stroke is higher in women than in men in the United States.⁵ Many of the major risk factors are similar regardless of sex, but in some cases, the same risk factor can confer a higher risk of stroke in women than in men. For example, research suggests that women with atrial fibrillation, especially women over 65 years of age, have a higher risk of stroke than men with the same condition.⁶ Similarly, diabetes is associated with a higher risk of stroke in women than in men.^{5 , 7}

In addition, some risk factors are specific to women; these often involve changes in the levels of certain hormones that can occur during specific life stages, such as during pregnancy, childbirth, and menopause. The risk of stroke, including ischemic stroke and subarachnoid hemorrhage, is especially high during pregnancy. Pre-eclampsia and certain adverse pregnancy outcomes (e.g., preterm delivery) have been shown to substantially increase a woman’s long-term risk of stroke. Women who are receiving hormone replacement therapy to alleviate menopause symptoms may also be at a higher risk.²

Magnetic resonance imaging (MRI) and computed tomography (CT) are commonly used to diagnose stroke. Stroke severity can be assessed with a standardized scale, such as the NIH Stroke Scale, which was developed using research supported by the National Institute of Neurological Disorders and Stroke (NINDS). Treatment varies depending on the type of stroke, but in general, it involves using medications or surgical procedures to minimize the injury to the brain and providing interventions to prevent recurrence. Rehabilitation services, such as physical, occupational, and speech therapies, help patients return to activities of daily living and improve their overall quality of life.^{4 , 8}

Some active areas of stroke research include investigations that aim to better understand the risk factors for stroke and the associations between stroke and certain comorbidities. Researchers are also evaluating potential new treatment options and methods for improving rehabilitation and post-stroke recovery.

StrokeNet is a network of clinical trials that are investigating methods for treating and preventing strokes, as well as strategies for rehabilitation and recovery. Created in 2013 by NINDS, the network includes 27 regional coordinating centers that are linked to stroke hospitals across the United States. The DEFUSE 3 trial is one of the trials that was conducted through StrokeNet. Results from this trial suggest that the window of time for restoring blood flow with a thrombectomy may be longer than expected for some patients who have had an ischemic stroke. Brain imaging techniques may be able to identify the patients who could benefit from a thrombectomy outside the usual 6-hour timeframe.⁹