From the Guidelines
A recent definition of stroke (ACV - Accidente Cerebrovascular) is a neurological condition characterized by a sudden interruption of blood flow to the brain, resulting in brain cell damage due to lack of oxygen and nutrients, with a focus on time-sensitive treatment to minimize brain damage and improve recovery potential. This definition is supported by the most recent guidelines, such as the 2021 guideline for the prevention of stroke in patients with stroke and transient ischemic attack from the American Heart Association/American Stroke Association 1. The definition emphasizes that stroke is a medical emergency that can occur through two main mechanisms: ischemic stroke (approximately 85% of cases), caused by a blood clot blocking an artery supplying the brain, or hemorrhagic stroke, resulting from a ruptured blood vessel causing bleeding in or around the brain.
Key Points
- Stroke is a time-sensitive medical emergency that requires immediate attention to minimize brain damage and improve recovery potential 1.
- The definition of stroke recognizes transient ischemic attacks (TIAs) as temporary stroke-like symptoms that resolve within 24 hours but serve as important warning signs 1.
- Modern definitions highlight the urgency of treatment within the first few hours after symptom onset to minimize brain damage and improve recovery potential, with the common phrase "time is brain" emphasizing this point 1.
- The risk of recurrent ischemic stroke and hemorrhagic transformation after stroke is significant, and anticoagulation reduces the risk of recurrent ischemic stroke but increases the risk of cerebral hemorrhage during the acute poststroke phase 1.
Clinical Implications
The recent definition of stroke has significant implications for clinical practice, emphasizing the need for rapid diagnosis and treatment to improve outcomes and reduce permanent disability. This includes the use of anticoagulation therapy to reduce the risk of recurrent ischemic stroke, while also considering the risk of hemorrhagic transformation and delaying initiation of oral anticoagulation in patients with large cerebral infarcts or early signs of hemorrhage on neuroimaging 1.
From the Research
Definition of Acute Cerebrovascular Accident (CVA) or Stroke
- Stroke is a clinically defined syndrome of acute, focal neurological deficit attributed to vascular injury (infarction, haemorrhage) of the central nervous system 2
- Acute ischemic stroke (AIS) is defined as sudden neurologic dysfunction caused by focal brain ischemia with imaging evidence of acute infarction 3
- Transient ischemic attack (TIA) is defined as an ischemic episode with neurologic deficits but without acute infarction 3
- TIA is also defined as a brief episode of reversible neurological deficits caused by focal and temporary central nervous system ischemia 4
Types of Stroke
- Ischemic stroke: accounts for approximately 85% of strokes, predominantly caused by small vessel arteriolosclerosis, cardioembolism, and large artery athero-thromboembolism 2
- Intracerebral haemorrhage: accounts for approximately 15% of strokes, can be deep (basal ganglia, brainstem), cerebellar, or lobar 2
Diagnosis and Management
- The ABCD2 score is a validated measure that can help predict which patients are at greatest risk of stroke after TIA 5
- Dual antiplatelet therapy with aspirin and clopidigrel is generally indicated for minor noncardioembolic ischemic strokes and high-risk transient ischemic attacks 3, 6
- Secondary prevention of ischemic stroke includes optimization of chronic disease management, nonpharmacologic lifestyle interventions, and pharmacologic interventions 6