Stroke Overview
- After heart disease and cancer, stroke is the biggest cause of premature death in America. Stroke is a major cause of morbidity, mortality, and functional disability. Targeted interventions such as physical activity, smoking, and a healthy diet (low in sodium) could reduce blood pressure and the burden of stroke.1 (See Stroke prevention). Unlike heart attack, there are three different types of stroke.
- Ischemic stroke occurs when vessels carrying blood to brain become blocked by a blood clot and oxygen and nutrients cannot get to a part of the brain. Sometimes the clot can form in another part of the body, becomes dislodged and free-floating (an embolus). The embolus can make its way through the bloodstream to the brain where it can cause an ischemic stroke. This accounts for 85% of all strokes. Ischemic strokes accounts for >10% of all deaths globally and are the third most common cause of mortality in developed countries.2
- Hemorrhagic stroke (non-ischemic stroke) occurs when blood vessels in the brain burst causing blood leaks in or around the brain. This accounts for 15% of all strokes. The leaking blood fills the space between the brain and skull (subarachnoid hemorrhage). This can also occur if a defective artery in the brain bursts and fills the surrounding tissue with blood (cerebral hemorrhage). In both cases there is poor blood flow to the brain, plus the accumulation of leaking blood with excessive pressure on the brain.
- There is a high burden of silent heart disease in people with stroke (62%). The prevalence is even higher in patients with evidence of carotid and/or femoral plaque (84%).3 A significant (>50%) stenosis of carotid arteries confer a 6-fold risk of coronary plaques.3
- Cardiac mortality is nearly twice as high as mortality owing to recurrent stroke, but long-term risk of all stroke, (fatal or nonfatal) is approximately twice the risk of all cardiac events.3, 4 The high risk of nonfatal recurrent stroke reinforces the importance of therapies aimed at preventing stroke recurrence in addition to preventing cardiac events.4
- The high burden of heart disease in patients with stroke points to the importance of secondary prevention of cardiovascular disease (CVD). It has been shown recently that routine revascularization (coronary angioplasty, stent or bypass surgery) does not improve major clinical outcomes (heart attack or deaths) compared to intensive medical therapy in stable heart disease, but it improves symptom control.5, 6 Statin therapy reduces the risk of an ischemic stroke by as much as 50% but remains underutilized.7
- There is no need to systematically image coronary arteries in patients with stroke, unless individuals have symptoms of heart disease or have evidence of ischemia on noninvasive tests.3In short, most survivors of a stroke will also have heart disease and probably will die from heart disease rather than from a repeat stroke.3
- Lifestyle choices may reduce stroke risk by 80%.8 A person who engages in healthy lifestyle choices may have an 80% reduced risk of first time stroke, according to research. Two factors that can significantly reduce this first-time incidence rate are healthy lifestyle choices and emergency room interventions.
- Since 77% of the 795,000 strokes that occur per year in the US are first events, people’s adoption of daily health habits have the potential to greatly reduce strokes overall. 8 Healthy lifestyle choices – don’t smoke, follow a healthy low fat diet with plenty of fruits and vegetables, if you consume alcohol do so in moderation, keep your body weight within normal limits, and exercise regularly.
Sources
1. O’Donnell M. J., Xavier D, Liu L, et al. Risk factors for ischaemic and intracerebral haemorrhagic stroke in 22 countries (the INTERSTROKE study): a case-control study. Lancet. Jul 10 2010;376(9735):112-123.
2. Gunarathne A, Patel JV, Gammon B, Gill PS, Hughes EA, Lip GY. Ischemic stroke in South Asians: a review of the epidemiology, pathophysiology, and ethnicity-related clinical features. Stroke. Jun 2009;40(6):e415-423.
3. Amarenco P, Lavallee PC, Labreuche J, et al. Prevalence of coronary atherosclerosis in patients with cerebral infarction. Stroke. Jan 2011;42(1):22-29.
4. Dhamoon MS, Sciacca RR, Rundek T, Sacco RL, Elkind MS. Recurrent stroke and cardiac risks after first ischemic stroke: the Northern Manhattan Study. Neurology. Mar 14 2006;66(5):641-646.
5. Boden WE, O’Rourke R A, Teo KK, et al. Optimal Medical Therapy with or without PCI for Stable Coronary Disease. N Engl J Med. Mar 26 2007.
6. Hochman JS, Steg PG. Does preventive PCI work? N Engl J Med. Apr 12 2007;356(15):1572-1574.
7. Ridker PM, Danielson E, Fonseca FA, et al. Rosuvastatin to prevent vascular events in men and women with elevated C-reactive protein. N Engl J Med. Nov 20 2008;359(21):2195-2207.
8. Goldstein L B, Bushnell CD, Adams RJ, et al. Guidelines for the Primary Prevention of Stroke. A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke. Dec 6 2010.