Preventing Cardiovascular Disease 10 Preventing Cardiovascular Disease

Prevalence of Cardiovascular Disease About 30% of all deaths in the US are attributed to cardiovascular disease (CVD) CVD: array of conditions that affect the heart and the blood vessels More than 1/3 of adults have some form of disease of the heart and blood vessels About 60% of deaths from heart disease have no previous symptoms

Prevalence of Cardiovascular Disease (cont’d.) Examples of CVD Coronary heart disease Stroke Peripheral vascular disease Narrowing of the peripheral blood vessels Congenital and rheumatic heart disease Atherosclerosis High blood pressure Congestive heart failure

Stroke Stroke is a condition in which a blood vessel that feeds the brain ruptures or is clogged, disrupting blood flow to the brain Third leading cause of death in the US Most significant contributor to mental and physical disability

Stroke Risk Factors Table 10.1. Stroke Risk Factors

Coronary Heart Disease Coronary heart disease (CHD) is a condition in which arteries that supply the heart muscle with oxygen are narrowed by fatty deposits Leading cause of death in the U.S. Several major risk factors for CHD are preventable and reversible Risk factor analyses evaluate a person’s lifestyle and genetics Place an individual in one of five risk categories for potential development of CHD

Leading Risk Factors for CHD Medical factors that lower risk: Blood pressure less than 120/80 Smoking less or quitting High-density lipoprotein (HDL) cholesterol 40 mg/dL or higher “Good” cholesterol; helps clear cholesterol from blood Low-density lipoprotein (LDL) cholesterol less than 100 mg/dL “Bad” cholesterol; increases blood pressure

Critical Thinking

Physical Inactivity Physical activity and aerobic exercise Increase cardiorespiratory endurance Control blood pressure Reduce body fat Lower blood lipids and improve HDL Prevent and help control diabetes Decrease low-grade inflammation Increase and maintain good heart function

Abnormal Electrocardiograms The electrocardiogram (ECG or EKG) measures the heart’s function Heart rate, heart rhythm, axis of the heart, enlargement or hypertrophy of the heart, and myocardial infarction Taken at rest, during exercise, during recovery Stress ECG shows tolerance of heart to increased physical activity Recovery ECG monitors the return of the heart’s activity to normal conditions

Key Terms Electrocardiogram (ECG or EKG) Stress electrocardiogram Recording of electrical activity of the heart Stress electrocardiogram Exercise test during which workload is increased to maximal fatigue Blood pressure and 12-lead electrocardiographic monitoring

Normal Electrocardiogram Figure 10.3. Normal electrocardiogram.

Abnormal Electrocardiogram Figure 10.4. Abnormal electrocardiogram showing a depressed S-T segment.

Abnormal Cholesterol Profile Blood lipids (cholesterol and triglycerides) are carried in the bloodstream by protein molecules of HDLs, LDLs, very-low-density lipoproteins (VLDLs), and chylomicrons Cholesterol For building cell membranes, some hormones, fatty sheath around nerve fibers, etc. Triglycerides Fats formed by glycerol and three fatty acids

Abnormal Cholesterol Profile (cont’d.) Very-low-density lipoproteins (VLDLs) Triglyceride, cholesterol, and phospholipid- transporting molecules in the blood Chylomicrons Triglyceride-transporting molecules An abnormal cholesterol profile contributes to atherosclerosis Typical symptoms of heart disease, such as angina pectoris, do not start until the arteries are about 75% blocked

Key Terms Atherosclerosis Myocardial infarction (heart attack) Fatty/cholesterol deposits in the walls of the arteries leading to formation of plaque Myocardial infarction (heart attack) Damage to or death of an area of the heart muscle as a result of an obstructed artery Angina pectoris Chest pain associated with CHD

Abnormal Cholesterol Profile (cont’d.) Cholesterol seems not to cause a problem until it is oxidized by free radicals In reverse cholesterol transport, HDL molecules help preventing plaque from forming in the arteries – they carry cholesterol to the liver, where it is changed to bile and excreted

Healthy and Diseased Arteries Figure 10.5. Comparison of a normal health artery (A) and diseased arteries (B and C)

Cholesterol Guidelines Table 10.3. Cholesterol Guidelines

Counteracting Cholesterol Saturated and trans fats (trans fatty acids) raise cholesterol levels more than anything else Saturated fats are found mostly in meats and dairy products Unsaturated fats are mainly of plant origin and cannot be converted to cholesterol Antioxidants may provide benefits A single unstable free radical (oxygen compound produced during metabolism) can damage LDL and accelerate the atherosclerotic process

Trans Fats Foods containing trans fatty acids, hydrogenated fat, or partially hydrogenated vegetable oil elevate LDLs and lower HDLs Trans fats are found primarily in processed foods that have been chemically altered through additives, or manufactured through combination or other methods

Lowering LDL Cholesterol LDL cholesterol levels can be lowered through dietary changes, losing body fat, taking medication, and by participating in a regular aerobic exercise program A diet lower in saturated fat, trans fats, and cholesterol and high in fiber is recommended NCEP guidelines to decrease LDL cholesterol allow for a diet with up to 35% of calories from fat, including 10% from polyunsaturated fats and 20% from monounsaturated fats

Saturated Fat Replacement in the Diet Research studies involving almost 350,000 people failed to prove a significant association between saturated fat intake and risk of CHD Researchers are focusing on the foods in the American diet that have replaced saturated fat

Elevated Triglycerides Triglycerides make up most of the fat in our diet and most of the fat that circulates in the blood Speed up plaque formation Manufactured in the liver from refined sugars, starches, and alcohol

Triglycerides Guidelines Table 10.6. Triglycerides Guidelines

Elevated Triglycerides LDL phenotype B Some people consistently have slightly elevated triglyceride levels (above 140 mg/dL) and HDL cholesterol levels below 35 mg/dL 80% of these people have a genetic condition called LDL phenotype B – higher risk for atherosclerosis and CHD

Cholesterol-Lowering Medications Statin group Lower cholesterol by 60% in 2 to 3 months Slow cholesterol production and increase liver’s ability to remove cholesterol Decrease triglycerides Produce small HDL increases Undesireable side effects

Cholesterol-Lowering Medications (cont’d.) Other drugs effective in reducing LDL cholesterol are bile acid sequestrans, which bind the cholesterol found in bile acids High dosages (1.5 to 3 grams per day) of nicotinic acid or niacin (a B vitamin) also help lower LDL cholesterol, Lp(a), and triglycerides, and increase HDL cholesterol

Elevated Homocysteine Homocysteine is an amino acid that, when allowed to accumulate in the blood, may lead to plaque formation and blockage of arteries Five servings of fruits and vegetables daily can provide enough folate and vitamin B6 to clear homocysteine from the blood

Homocysteine Guidelines Table 10.7. Homocysteine Guidelines

Inflammation Inflammation hidden deep in the body is a common trigger of heart attacks C-reactive protein (CRP) levels increase with inflammation; elevated level are an indicator of potential cardiovascular events

High-Sensitivity CRP Guidelines Table 10.8. High-Sensitivity CRP Guidelines

Diabetes Diabetes mellitus: blood glucose is unable to enter cells Insulin: hormone secreted by the pancreas; essential for metabolism of blood glucose and maintenance of blood glucose level Insulin resistance: inability of the cells to respond appropriately to insulin Chronic high blood sugar leads to CVD, stroke, nerve damage, vision loss, kidney damage, and decreased immune function

Blood Glucose Guidelines Table 10.9. Blood Glucose Guidelines

Types of Diabetes Type 1 diabetes (juvenile diabetes) Insulin-dependent diabetes mellitus (IDDM) Pancreas produces little or no insulin Type 2 diabetes (adult-onset diabetes) Non–insulin-dependent diabetes (NIDDM) Insulin is not processed properly

Types of Diabetes (cont’d.) 60 to 80% of type 2 diabetes is related to overeating, obesity, and lack of physical activity Once limited primarily to overweight adults, now half of new cases are diagnosed in children Regular exercise helps increase insulin sensitivity and decreases risk for diabetes

Glycemic Index Foods high in the glycemic index cause a rapid increase in blood sugar Diet with many high-glycemic foods increases risk for CVD in people with high insulin resistance and glucose intolerance

Hemoglobin A1c Test Hemoglobin A1c test measures amount of glucose in a person’s blood over last 3 months Goal for diabetics is to keep HbA1c under 7% People with type 2 diabetes should have an HbA1c test twice per year

Metabolic Syndrome Metabolic syndrome is an array of metabolic abnormalities that contribute to development of atherosclerosis triggered by insulin resistance: Low HDL cholesterol High triglycerides High blood pressure Increased blood-clotting mechanism

Diagnosis of Metabolic Syndrome

Blood Pressure Blood pressure is the force exerted against the walls of blood vessels by blood; measured in millimeters of mercury (mm Hg) Systolic blood pressure (higher number) Pressure exerted against walls of arteries during contraction (systole) of the heart Diastolic blood pressure (lower number) Pressure exerted against walls of arteries during relaxation (diastole) of the heart Ideal blood pressure is 120/80 or lower

Hypertension Hypertension is chronically elevated blood pressure, above 140/90 CVD risk doubles with each additional 20/10 Blood pressures ranging from 120/80 to 139/89 are prehypertension “Silent killer” damages epithelial lining of arteries, risk factor for CHD, congestive heart failure, stroke, kidney failure, osteoporosis

Blood Pressure Guidelines Table 10.10. Blood Pressure Guidelines (expressed in mm Hg)

Treatment of Hypertension 90% of hypertension has no definite cause (“essential hypertension”) and is treatable Aerobic exercise and weight reduction Diet: Low salt/fat, high potassium/calcium Lower alcohol and caffeine intake Smoking cessation Stress management Antihypertensive medication

Long-Term Aerobic Exercise and Resting Blood Pressure Table 10.12. Effects of Long-Term (14-18 years) Aerobic Exercise on Resting Blood Pressure

Treatment of Hypertension The remaining 10% of hypertensions are caused by pathological conditions, typically of the kidneys, adrenal glands, or aortic artery With pathological hypertension, the cause has to be treated before blood pressure is corrected

Excessive Body Fat Excessive body fat is independent risk factor for CHD; augmented by risk factors such as high blood lipids, hypertension, and diabetes People who store body fat in the abdominal area are at higher risk for disease than people who store fat in the hips and thighs Abdominal fat stored around internal organs (visceral fat) increases risk more than abdominal fat stored subcutaneously or retroperitoneally

Body Weight, Physical Activity, and Heart Failure Risk Table 10.13. Relationship Between Body Weight, Physical Activity, and Heart Failure Risk

Cigarette Smoking About 20% of all deaths from CVD are attributable to smoking Smoke releases nicotine and 1,200 other toxic compounds into the bloodstream Destructive to arterial lining Formation of blood clots Decrease in HDL cholesterol Raises blood pressure Fatal cardiac arrhythmias

Tension and Stress The human body responds to stress by producing catecholamines such as epinephrine and norepinephrine These “fight or flight” hormones increase heart rate, blood pressure, and blood glucose levels Angina risk increases following an outburst of anger and doubles the risk for a heart attack in the next two hours

Personal and Family History Individuals with previous cardiovascular problems are at higher risk Many risk factors are reversible Genetic predisposition for premature CHD Heart attack before age 55 (males) Heart attack before age 65 (females)

Age Incidence of heart disease increases with age Less physical activity Poorer nutrition Obesity Process of heart disease begins early in life Chronological vs. physiological age

Other Risk Factors for CHD Gum disease Oral bacteria can cause inflammation Loud snoring Sleep apnea stops breathing Low birth weight (under 5.5 pounds)

Cardiovascular Risk Reduction Most risk factors are reversible and preventable Aspirin therapy Healthy habits Willpower and commitment A healthier lifestyle, free of cardiovascular problems, leads to well-being and longevity

Assess Yourself Is your diet low in saturated fat, trans fats, and refined carbohydrates? Do you understand the following concepts? Cardiovascular disease and coronary heart disease How a healthy lifestyle can prevent cardiovascular disease Risk factors for coronary heart disease How to reduce risk for coronary heart disease