A CVA, or cerebrovascular accident, is the medical term for a stroke. It happens when blood flow to part of the brain is suddenly cut off or when a blood vessel in the brain ruptures, causing brain cells to die within minutes. About 87% of all strokes are ischemic, meaning a blood clot blocks an artery supplying the brain. The remaining 13% are hemorrhagic, caused by bleeding in or around the brain.
How a CVA Damages the Brain
Your brain cells need a constant supply of oxygen and glucose delivered through blood flow. When a clot or rupture interrupts that supply, the affected cells begin to die rapidly. Without fuel, neurons release a flood of signaling chemicals that trigger a cascade of damage: calcium builds up inside cells, toxic free radicals form, and the energy-producing structures within cells start to fail.
Surrounding the core of dead tissue is a region called the ischemic penumbra, where cells are stressed and damaged but not yet dead. This is the tissue that emergency treatment aims to save. The penumbra can survive for hours if some blood flow trickles through, but without intervention, it gradually dies too, expanding the area of permanent brain injury.
Ischemic vs. Hemorrhagic Stroke
Ischemic strokes, the most common type, occur when a blood clot forms in a brain artery or travels there from somewhere else in the body (often the heart). Because the clot can potentially be dissolved or removed, time-sensitive treatments exist that can limit damage.
Hemorrhagic strokes account for about 13% of cases and come in two forms. Intracerebral hemorrhage (10% of all strokes) happens when a weakened blood vessel bursts inside the brain itself. Subarachnoid hemorrhage (3%) involves bleeding in the space between the brain and its surrounding membrane, often from a ruptured aneurysm. Hemorrhagic strokes tend to be more severe. They strike younger patients on average, cause more intense initial damage, and carry a higher risk of death in the first days and weeks.
Recognizing the Symptoms
The American Stroke Association uses the acronym F.A.S.T. to help people identify a stroke quickly:
- Face drooping: One side of the face goes numb or droops. A lopsided smile is a telltale sign.
- Arm weakness: One arm feels weak or numb. If you ask the person to raise both arms, one drifts downward.
- Speech difficulty: Words come out slurred or garbled.
- Time to call 911: Every minute without treatment means more brain tissue lost.
Beyond the classic signs, strokes can also cause sudden confusion, trouble understanding what others are saying, vision loss in one or both eyes, dizziness, and loss of balance or coordination. These symptoms appear without warning and are not subtle. If any of them come on suddenly, treat it as an emergency.
What Happens at the Hospital
The first priority is a brain scan, typically a non-contrast CT scan, which can be completed within minutes of arrival. The goal is to determine whether the stroke is caused by a clot or by bleeding, because the treatments are completely different. Hospitals aim to have this scan done and interpreted within 45 minutes of the patient walking through the door.
For ischemic strokes, clot-dissolving medication can be given intravenously within 4.5 hours of symptom onset. Current guidelines endorse two versions of this medication, and the decision to administer it is made immediately after the brain scan rules out bleeding. For some patients who arrive after the 4.5-hour window, or who wake up with stroke symptoms, advanced imaging can determine whether salvageable brain tissue remains. In those cases, treatment may still be effective up to 24 hours after symptoms began.
When a large artery in the brain is blocked, a procedure called mechanical thrombectomy may be performed. A catheter is threaded through a blood vessel to physically remove the clot. Within the first 6 hours, this option is available for a broad range of patients. Between 6 and 24 hours, eligibility is more selective, requiring brain imaging that confirms enough tissue can still be saved to justify the procedure.
The Biggest Risk Factor: High Blood Pressure
Hypertension is the single most important modifiable risk factor for stroke. Across a pooled analysis of 1.8 million people, high blood pressure roughly doubled overall stroke risk, with the strongest effect seen in hemorrhagic stroke. Even blood pressure readings at or above 130 mmHg systolic, which falls below the traditional “high” threshold, increase the risk of cerebrovascular events.
The good news is that lowering blood pressure has a measurable payoff. Each 5-point reduction in systolic blood pressure lowers stroke risk by about 22%. Among people with diabetes, intensive blood pressure control (keeping systolic pressure below 120) reduced stroke incidence by 41%.
Other major risk factors include high cholesterol, smoking, physical inactivity, diabetes, atrial fibrillation (an irregular heart rhythm that allows clots to form in the heart), and obesity. Many of these interact with and amplify each other.
TIA: The Warning Stroke
A transient ischemic attack, or TIA, produces the same symptoms as a full stroke but resolves on its own, usually within minutes to hours. It happens when a clot temporarily blocks blood flow and then breaks up before causing permanent damage. People sometimes call it a “mini-stroke,” but that label understates how serious it is.
A TIA is one of the strongest warning signs that a full stroke is coming. About 5% of people who have a TIA experience a stroke within 7 days, and roughly 9% have one within 90 days. That risk is highest in the first 48 hours, which is why a TIA warrants the same emergency response as a completed stroke. The upside is that fast evaluation and treatment after a TIA, such as blood thinners and blood pressure management, can dramatically reduce the chance of a subsequent stroke.
Reducing Your Risk
Stroke prevention comes down to managing the conditions that damage blood vessels over time. The American Heart Association’s current guidelines emphasize starting early with lifestyle changes: regular physical activity, maintaining a healthy weight, avoiding tobacco, and prioritizing consistent sleep. For cholesterol, the primary prevention target is an LDL level below 100 mg/dL for people at borderline or intermediate cardiovascular risk, and below 70 mg/dL for those at high risk.
Newer risk calculators now estimate both 10-year and 30-year risk of heart attack or stroke for adults aged 30 to 79, which helps identify people who might benefit from cholesterol-lowering medication earlier than previous guidelines suggested. The shift reflects growing evidence that cumulative exposure to high blood pressure and high cholesterol over decades, not just levels at a single point in time, drives stroke risk.
Recovery After a CVA
Recovery varies enormously depending on the type of stroke, its severity, and how quickly treatment was received. Ischemic stroke patients generally have better outcomes than hemorrhagic stroke patients, partly because effective acute treatments exist and partly because the initial brain injury tends to be less severe. Hemorrhagic stroke survivors typically require longer and more intensive hospitalization, both in the acute phase and during rehabilitation.
Rehabilitation usually begins within days of the stroke and can continue for months or longer. It may involve physical therapy to regain movement, speech therapy to recover language skills, and occupational therapy to relearn daily tasks. The brain has a limited ability to rewire itself after injury, and the mechanisms of recovery appear to differ between ischemic and hemorrhagic strokes, which is why rehabilitation programs are increasingly tailored to the specific type of stroke a person experienced.