Chapter 14 Cardiovascular Diseases: Understanding Risks and Measures of Prevention

1. Chapter 14Cardiovascular Diseases:Understanding Risks and Measures of Prevention

2. Understanding Cardiovascular Diseases • More than 70 million Americans have some form. • Fifty percent of all deaths in the United States each year result from cardiovascular disease. • The term refers to a number of conditions that damage the heart or arteries. • If the coronary arteries (large blood vessels that carry blood to and from the heart) become diseased or blocked, a heart attack may result.

3. Understanding Cardiovascular Diseases • If the heart does not receive a continual supply of blood and oxygen, the heart cells die and an infarction occurs. • If the blood supply to the heart is only partially blocked, the condition is called ischemia. • A stroke occurs when there is damage to the brain from an insufficient supply of blood to the brain cells. • Cardiovascular diseases are preventable and primarily are lifestyle diseases.

4. The Heart and Blood Vessels • Arteries—Carry oxygenated blood from the heart to all organs and tissues in the body • Veins—Return blood to the heart after oxygen and nutrients have been exchanged for carbon dioxide and waste products • Capillaries—Tiny blood vessels that branch out from arteries and veins and circulate blood to all the cells in the body • Myocardium—Muscular wall of the heart • Heart—About the size of a fist

5. Heart and Major Arteries

6. The Heart • Has four chambers: • Upper two chambers are called the left atrium and right atrium. • Lower two chambers are called the left ventricle and right ventricle.

7. Flow of Blood Through the Heart • Blood that is depleted of oxygen returns to the heart via the right atrium. • It flows to the right ventricle and is pumped to the lungs, where it is reoxygenated and returned to the left atrium via the pulmonary vein. • This fresh blood is pumped throughout the body’s tissues from the left ventricle through the large artery called the aorta.

8. Regulating Blood Flow • The cardiovascular system is equipped with one-way valves in the chambers of the heart and blood vessels. • With every heartbeat, the valves open and close to allow blood to flow in one direction. • If the veins in the legs are weakened, blood tends to accumulate in the legs, producing varicose veins. • Varicose veins are a common, but less serious, form of valve damage.

9. Heart Valves

10. Atherosclerosis • Hardening of the arteries • One form is the formation of plaque. • If coronary arteries become partially blocked and the heart does not receive enough oxygen, chest pain, called angina pectoris, occurs. • If the coronary artery is blocked completely, a heart attack occurs.

11. Atherosclerosis

12. Diagnosis of a Heart Attack • More than a million people are admitted to hospitals annually with possible heart attacks. • Diagnosing a heart attack is time-consuming and costly. • Blood levels of the following proteins change during a heart attack: • Creatine kinase • Troponin • Myoglobin • Myosin

13. Repairing Blocked Arteries • Angiocardiography—Procedure that visualizes the flow of blood through the arteries and chambers of the heart to confirm a blocked artery or restricted blood flow. • Arteriography—Invasive procedure that gives a precise image of the flow of blood through the coronary arteries that supply blood to the heart.

14. Repairing Blocked Arteries • Coronary bypass surgery—The diseased segment of the artery is cut out and replaced with a grafted piece of good artery to restore normal flow of blood to the heart. • Open-heart surgery—Heart is exposed while being repaired and blood is diverted through a heart–lung machine.

15. Repairing Blocked Arteries • An alternative surgical procedure is percutaneous transluminal coronary angioplasty, in which a balloon is inserted into the artery and inflated so it pushes the plaque against the wall of the artery, opening the artery. • Costs less than bypass surgery, but the blockage recurs many times.

16. Repairing Blocked Arteries • Alternative to bypass surgery is “stenting,” which involves inserting a catheter into an artery in the arm or leg, threading it to the blockage point, and inserting props or “stents” to open the artery.

17. Repairing Blocked Arteries • Carotid endarterectomy is used to clear plaque. • A stent is inserted into the carotid artery during the procedure to keep blood from flowing to the brain.

18. Stroke • Third leading cause of death in the United States after coronary heart disease and cancer. • High blood pressure is related to at least 70% of all strokes. • It is a form of cardiovascular disease that affects arteries supplying blood to the brain. • Brain cells die within minutes without oxygen. • A person who has had a stroke can lose the ability to speak, have one arm or leg become paralyzed, become paralyzed on one side of the body, or die.

19. Stroke • Can occur from injuries to the head or from weak spots in the arteries, called aneurysms, that balloon and rupture. • Can occur when a weak heart cannot pump enough blood to the brain. • Four kinds of strokes are defined medically.

20. Stroke • Two kinds of stroke are caused by clots that block blood flow to the brain. • Cerebral thrombosis and cerebral embolism are the most common types of stroke; both are caused by clots. • Two are caused by the rupture and hemorrhage of an artery supplying blood to the brain. • Cerebral and subarachnoid hemorrhages are caused by ruptured blood vessels. These occur less frequently, but have a high fatality rate.

21. Warning Signs of a Stroke • Signs of a stroke include: • Sudden weakness or numbness of the face, arm, or leg on one side of the body • Sudden dimness or loss of vision, especially in one eye • Loss of speech, difficulty understanding speech, or trouble talking • Sudden, severe headaches with no known cause • Unexplained unsteadiness, dizziness, or fall

22. Preventing a Stroke • Reduce the risk factors that are controllable largely by changes in lifestyle: • High blood pressure • Heart disease • Cigarette smoking • Transient ischemic attacks • High red blood cell count

23. Risk Factors for Cardiovascular Disease • Research seems to indicate that plaque begins to build up in the arteries at an early age; this is why positive lifestyle behaviors are important at all ages. • Cholesterol—There are two major kinds of cholesterol: HDL (“good” cholesterol) and LDL (“bad” cholesterol). • Familial hyperlipidemia—A rare inherited disease that results in high levels of cholesterol in the blood.

24. Measuring Cholesterol Levels • Total cholesterol levels are measured in milligrams per deciliter (mg/dl) of blood. • Cholesterol level below 200 mg/dl indicates a relatively low risk of coronary heart disease. • A level of 240 mg/dl or higher doubles the risk of coronary heart disease (CHD). • Total cholesterol may not be a reliable indicator because high levels of HDL may counteract the bad effects of a high LDL count.

25. Cholesterol, Statins, and Inflammation • Statins are a class of drugs that reduce the level of blood cholesterol. • Statins also reduce the level of reactive protein in the blood.

26. High Blood Pressure • If the cause of high blood pressure (HBP) is unknown, it is referred to as essential hypertension. • This includes 90% to 95% of cases of HBP. • The remaining HBP cases are symptoms of recognizable diseases, such as kidney abnormality, congenital defect of the aorta, or adrenal gland tumor. • These types of hypertension are referred to as secondary hypertension.

27. Measuring Blood Pressure • The systolic pressure is the maximum pressure in the arteries that occurs when the heart contracts. • The diastolic pressure is the pressure between contractions, when the pressure falls as blood flows from one chamber to another. • Normal blood pressure is defined as less than 140/90 (systolic/diastolic).

28. Lowering Blood Pressure • Can be lowered by making the following lifestyle changes: • Lowering excessive caloric intake • Increasing physical activity • Decreasing salt and alcohol consumption • Consuming adequate amounts of potassium

29. Stages of High Blood Pressure

30. Cigarettes and CVD • Cigarette smoking is a major risk factor contributing to the development of heart disease, heart attacks, and strokes. • Smokers have a two to four times greater risk of dying from a heart attack than nonsmokers. • Risk of heart disease from secondhand smoke is also significant. • Smoking damages blood vessels carrying blood to the arms and legs, which could lead to gangrene.

31. The Metabolic Syndrome • Factors that are shared by people at risk for diabetes, CVD, and heart attack: • Waist circumference larger than 40 inches in men and 35 inches in women • Serum triglyceride level of 150 mg/dl or greater • Blood pressure 135/85 or higher

32. Stress • Main risk factor for heart disease is stress. • Type A behavior includes: • Irritation and impatience while waiting in lines. • Constantly feeling pressured. • Not letting other people finish what they are saying. • Always trying to show others how to do things correctly. • Playing games to win every time. • Not allowing time for relaxation.

33. Diet and CVD • A deficiency of only one nutrient can impair the body’s ability to use all others, even if the others are present in sufficient amounts. • Vitamin E: Antioxidant that removes lingering oxygen atoms that can damage body tissues. • B vitamins: Lower the levels of homocysteine in the blood. • Calcium: Deficiency is a risk factor for hypertension in persons of all ages.

34. Diet and CVD • Soy products: Help remove cholesterol from the blood and block oxidation of LDL, which prevents it from sticking to the walls of arteries. • Fish oils: Populations that consume large amounts of fish show lower rates of CHD than populations that do not. • Tea: Green and black tea contain antioxidant chemicals that help block oxidation of LDL in the blood.

35. Diet and CVD • Aspirin: Significantly reduces the risk of CHD and heart attacks. Helps “thin” blood and combats inflammation. If you feel you might be having a heart attack, call 911, and then take a couple of aspirin to help prevent clotting. • Alcohol: In one study, men who had one or two drinks a day over 12 years reduced their risk of dying from a heart attack by about 20% compared with men who did not drink alcohol.

36. Preventing Cardiovascular Disease • Now that you are armed with knowledge about reducing the chances of heart attacks and stroke, what needs to be done? • Reduce weight • Reduce consumption of foods with saturated fats • Eat a lot of fruits and vegetables • Take supplements • Don’t smoke • Be active