Mechanisms that Produce a Stroke

1. Mechanisms that Produce a Stroke • Blockage of an artery (80% of strokes) • --causes ischemia (inadequate blood flow) This • deprives the brain of oxygen and glucose, and • slows waste removal • --affected brain tissue functions abnormally or stops • functioning, and will die if ischemia persists • Rupture of an artery (20% of strokes) • --causes hemorrhage within or around the brain. This • distorts, compresses, and tears surrounding tissue ventricle Lumen

2. Stroke Risk Factors Relationship to pathology Directly or indirectly promote conditions that ‘encourage’ blockage or rupture of arteries supplying the brain: ventricle • Development of atherosclerotic plaque • Thrombus formation in heart or cerebral arteries • Physical stress and direct damage to walls of • large and small arteries Lumen

3. Stroke Risk Factors Behaviors / Lifestyles ‘Who We Are’ Medical Conditions (treatable/controllable) Age Gender Race/Ethnicity Family History Prior Stroke/TIA Cigarette Smoking Physical Inactivity Excess Alcohol Use Obesity Hypertension Heart Disease Myocardial Infarction Atrial Fibrillation Diabetes Mellitus Hyperlipidemia Carotid Stenosis ventricle Lumen

4. Stroke Risk Factors Behaviors or Lifestyles • Cigarette Smoking • Increases risk about 1.5X • The heavier the smoking, the greater the risk • 5 years after quitting, risk matches that for nonsmokers • Physical Inactivity • Sedentary lifestyle is independent risk factor • (30 min. moderate-to-vigorous daily exercise recommended) • Excessive Alcohol Consumption • ≥ 5 drinks/day and binge drinking • Obesity • Body mass index ≥ 30 doubles risk ventricle Lumen

5. Stroke Risk Factors Medical conditions: treatable or controllable • Hypertension • Blood pressure ≥ 140/90 mm Hg for extended periods • Heart Disease • Myocardial Infarction • Atrial Fibrillation • Diabetes Mellitus • Fasting plasma glucose ≥ 126 mg/dL • Hyperlipidemia • Total cholesterol ≥ 240 mg/dL accelerates atherosclerosis • Carotid Artery Stenosis • ≥ 70% narrowing of the carotid artery in the neck • Hypertension is the most significant treatable risk factor! increase risk of thrombus formation in heart, and thus embolic strokes ventricle

6. Stroke Risk Factors Unmodifiable conditions: ‘Who we are’ • Age • Risk of stroke doubles every 10 years after age 55 • Gender • Women’s first strokes occur when they are older • Race/Ethnicity • African-Americans 60% more likely to have a stroke, • and twice as likely to die compared to other groups • Family History • First-degree relative with stroke • Inherited defects influencing blood clotting • Previous Stroke or TIA • 1:6 ischemic stroke survivors has another stroke in 2 yrs • Having a TIA increases the chances of stroke 10 times ventricle Lumen

7. plaque Basilar Artery atherosclerotic plaque narrows lumen ( )

8. Aorta - Atherosclerosis Numerous ulcerated plaques

9. Carotid Bifurcation atherosclerotic plaque and thrombus Thrombus on plaque surface plaque Thrombus on plaque surface

10. Embolus Plugging Artery Piece of thrombus that traveled from heart Arterial wall ventricle Lumen Plugged lumen

11. Intracerebral Hemorrhage ventricle Lumen Clotted blood

12. Intracerebral Hemorrhage CT Scan - 3 Hours after onset of symptoms ventricles