What is stroke: A stroke or “brain attack” occurs when a blood clot blocks the blood flow in a vessel or artery or when a blood vessel breaks. There are two types of “brain attacks” — ischemic and hemorrhagic. When brain cells die during a stroke, abilities controlled by that area of the brain are lost. These abilities include speech, movement and memory. How a stroke patient is affected depends on where the stroke occurs in the brain and how much the brain is damaged.
With ischemic strokes, a blood clot blocks or “plugs” a blood vessel in the brain. Limited treatments are tPA “clot buster” or surgical removal of the clot within a 2-3 hour time window (and sometimes up to 6 hours).
- An estimated 7,000,000 Americans 20 years of age have had a stroke. Overall stroke prevalence during this period is an estimated 3%.
- The prevalence of silent cerebral infarction between 55 and 64 years of age is ~11%. This prevalence increases to 22% between 65 and 69 years of age; 28% between 70 and 74 years of age; 32% between 75 and 79 years of age; 40% between 80 and 85 years of age; and 43% at 85 years of age. Application of these rates to 1998 U.S. population estimates results in an estimated 13 million people with prevalent silent stroke every year.
- Silent stroke may be important in the development of AD since cerebral perfusion is often found to be reduced in association with an increased oxygen extraction fraction during an attack, a hemodynamic presentation typically found in AD patients.
- For the incidence, it is estimated that each year, ~795 000 people experience a new or recurrent stroke. From 1999 data, approximately 610,000 of these are first attacks, and 185 000 are recurrent attacks.
- On average, every 40 seconds, someone in the U.S. has a stroke. On average, every 4 minutes, someone dies of a stroke. Stroke accounted for ~1 of every 18 deaths in the U.S. in 2007.
- Each year, ~55,000 more women than men have a stroke.
- It now appears that coronary artery bypass grafting (CABG) surgery may induce cognitive loss in as many as 50% of patients undergoing this procedure.
- The number of TIAs in the U.S. has been estimated to be ~200,000 to 500,000 per year, with a population prevalence into ~5 million people. The prevalence of TIA increases significantly with older age. Approximately half of all patients who experience a TIA fail to report it to their healthcare providers.
With hemorrhagic strokes, a blood vessel in the brain breaks or ruptures.The occurrence rate of ischemic stroke is ~83% and for hemorrhagic it is ~17%.
- Among people 45 to 64 years of age, approximately 8% to 12% of ischemic strokes and 37% to 38% of hemorrhagic strokes result in death within 30 days.
- In a study of people 65 years of age recruited from a random sample of Health Care Financing Administration Medicare Part B eligibility lists in four US communities, the 1-month case fatality rate was 12.6% for all strokes, 8.1% for ischemic strokes, and 44.6% for hemorrhagic strokes.
- Approximately half of incident childhood strokes are hemorrhagic. Despite current treatment, 1 of 10 children with ischemic or hemorrhagic stroke will have a recurrence within 5 years.
Risk Factors: Some of the risk factors are: age, gender, race, family history, diabetes, high blood pressure, heart disease, smoking, weight, etc.