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Cardiovascular Disease

Cardiovascular Disease. D. Bellis McCafferty NFSC 370. Cardiovascular Disease – general term that means diseases of the heart and blood vessels

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Cardiovascular Disease

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  1. Cardiovascular Disease D. Bellis McCafferty NFSC 370

  2. Cardiovascular Disease – general term that means diseases of the heart and blood vessels • Coronary Heart Disease (CHD) – AKA Coronary Artery Disease and Ischemic Heart Disease – lack of blood flow to the network of blood vessels surrounding (and serving) the heart. The major cause is atherosclerosis. • Ischemia – insufficient blood flow in a tissue due to functional constriction or actual obstruction of a blood vessel.

  3. Atherosclerosis – thickening and hardening of the walls of the blood vessels caused by deposits of fatty material. Arteries most often affected are the abdominal aorta, coronary and carotid arteries. • Myocardial Infarction (MI) – Ischemia in the coronary arteries resulting in necrosis, tissue damage and sometimes sudden death. • Cerebrovascular Accident (CVA) – event in which the blood flow to a part of the brain is cut off. • Transient Ischemic attack (TIA) – temporary reduction in cerebral blood flow that causes temporary symptoms that mimic those of a CVA.

  4. Atherosclerosis Pathogenesis: “Response to Injury” theory 1. Formation of fatty streaks along arterial walls 2. Proliferation of smooth muscle cells, WBC and calcium  plaques. • Plaques cause the arteries to lose elasticity • Narrowing of arterial lumen • (Most people have well-developed plaques by age 30)

  5. Consequences 1. Loss of elasticity  injury to arterial wall 2. Platelet aggregation and blood clotting (response to injury) • Thrombosis: blood clot obstructs blood flow, causing tissue death • Embolism: clot breaks off and travels to smaller vessel and obstructs blood flow, causing tissue death.

  6. Angina: pain, pressure, and tightness in chest, back, neck, and arms, caused by lack of O2 to heart muscle 3. Hypertension (more pressure required to deliver blood to tissues if arteries are narrowed) • Further damage to blood vessels  more clots, etc.

  7. Dietary Treatment of High Blood Cholesterol in Adults NCEP’s updated clinical guidelines for cholesterol testing and management: ATP III (Adult Treatment Panel III) http://www.nhlbi.nih.gov/guidelines/cholesterol/atp3xsum.pdf “These guidelines are intended to inform, not replace, the physician’s clinical judgment, which must ultimately determine the appropriate treatment for each individual.”

  8. Focus: Lowering LDL cholesterol (major cause of CHD, and LDL-lowering therapy reduces risk for CHD) Major new feature: focus on primary prevention in persons with multiple risk factors.  New recommendation: All adults aged 20 yrs or older should obtain a fasting LP profile every 5 years (TC, HDL, LDL, TG).

  9. Blood Lipid Levels • Total cholesterol (adults) • desirable < 200 mg/dl • borderline high 200-239 mg/dl • high risk 240 mg/dl • LDL cholesterol • optimal <100 mg/dl (goal if CVD, DM or multiple RF’s*) • Above optimal 100-129 mg/dl • borderline high 130-159 mg/dl (<130 goal if 2+ RF’s**) • high risk >160 mg/dl (<160 goal if 0-1 RF) • HDL cholesterol 40 mg/dl (60: neg. risk factor) • Triglycerides (TG)  150 mg/dl (requires tx beyond LDL lowering if >200)

  10. To convert mmol/l of HDL or LDL cholesterol to mg/dl, multiply by 39. To convert mg/dl of HDL or LDL cholesterol to mmol/l, divide by 39. To convert mmol/l of triglycerides to mg/dl, multiply by 89. To convert mg/dl of triglycerides to mmol/l, divide by 89.

  11. Risk FactorsRF’s that modify LDL Goals: blue • Category I risk factors: • Intervention has been proven to decrease CVD risk • Category II risk factors: • Intervention is likely to decrease CVD risk • Category III risk factors: • Intervention may decrease risk • Category IV risk factors: • Intervention does not decrease risk

  12. Category I Risk Factors 1. Cigarette smoking • Doubles CVD risk • Synergistic w/other risk factors •  HDL, VLDL and BG levels 2. LDL Cholesterol •  sat’d fat intake •  cholesterol intake in some people •  trans FA intake • obesity

  13. 3. Hypertension •  Risk for stroke, CHD, and CHF • 140/90 mm Hg • Risk : AA, age, obesity Category II Risk Factors 1. Diabetes • LDL chol goal for people w/DM is 100 mg/dl 2. Physical Inactivity • Sedentary people (60% of US) have double the risk of developing CVD as active people. • Modifies other risk factors

  14. 3. HDL cholesterol <40 mg/dl • Greater effect than LDL? • Reverse cholesterol transport • Increased with: EXERCISE, estrogen replacement, loss of body fat, moderate consumption of alcohol 4. Obesity • BMI ranges • Affects glu tolerance, blood lipids, BP, etc. • Body fat distribution

  15. Category III Risk Factors 1. Psychosocial Factors • Correlated w/risk, but intervention is not strongly correlated with decreased risk. • Type “A” personality, stress, depression • Low education level 2. Triglycerides • Inversely correlated w/HDL • Increased with: high CHO, low fat, vegetarian diet, obesity, uncontrolled DM, excessive EtOH (and factors that decrease HDLs)

  16. 3. Lp(a): Early studies indicated strong correlation w/CHD risk • Conflicting evidence 4. Homocysteine • Strong + correlation w/premature ds. • with inadequate folate, B6 and B12 • Also smoking, inactivity, coffee (>1c/day) 5. Oxidative stress* • LDL damage • Inhibited* by vits C, E, b-carotene, mufa’s •  w/Iron, copper, zinc, and sat’d fat *no conclusive evidence (randomized trials) that supplemental antioxidants reduce disease risk - food vs. supplements

  17. 6. Alcohol consumption - moderate Category IV Risk Factors 1. Age Male gender and over 45 y/o Female gender and over 55 y/o 2. Family history MI <age 55 in a male first degree relative MI <age 65 in a female first degree relative (familial dyslipidemias)

  18. Therapeutic Lifestyle Changes (TLC) • Reduced intakes of saturated fats (<7% of total calories) and • Cholesterol (<200 mg per day) • Therapeutic options for enhancing LDL lowering such as plant stanols/sterols (2 g/day) and increased viscous (soluble) fiber (10-25 g/day) • Weight reduction • Increased physical activity

  19. Nutrient Composition of the TLC Diet Nutrient Saturated fat* Polyunsaturated fat Monounsaturated fat Total fat Carbohydrate† Fiber Protein Cholesterol Total calories (energy)‡ Recommended Intake Less than 7% of total calories Up to 10% of total calories Up to 20% of total calories 25-35% of total calories 50-60% of total calories 20-30 g/day Approximately 15% of total calories Less than 200 mg/day Balance energy intake and expenditure to maintain desirable body weight/prevent weight gain

  20. Drugs Affecting Lipoprotein Metabolism • HMG CoA reductase inhibitors (statins) • HDL (5-15%)  LDL (18-55%)  TG (7-30%) • Lovastatin, atorvastatin (Lipitor), simvstatin, etc. • Bile acid sequestrants •  hepatic synthesis of cholesterol • HDL (3-5%)  LDL (15-30%) • Cholestyrmaine • Nicotinic acid •  hepatic VLDL synthesis and thus LDL formation •  LDL (5-25%)  TG (20-50%) • Fibric Acids • Several mechanisms of action • HDL (10-20%)  LDL (5-20%)  TG (20-50%) • Gemfibrozil

  21. Metabolic Syndrome • Cluster of risk factors that enhance risk for CHD at any given LDL cholesterol level. • Diagnosis: 3 or more of the following risk determinants: Defining Level Waist Circumference† >102 cm (>40 in) >88 cm (>35 in) ³150 mg/dL <40 mg/dL <50 mg/dL ³130/³85 mmHg ³110 mg/dL Risk Factor Abdominal Obesity* Men Women Triglycerides HDL cholesterol Men Women Blood pressure Fasting glucose

  22. Treatment of Metabolic Syndrome: • Treat/reduce underlying causes • TLC Diet: a higher intake of total fat (mostly unsaturated) can help  TG and HDL cholesterol in persons w/Metabolic Syndrome • Weight control • Physical activity • Plant stanols/sterols • Viscous (soluble) fiber

  23. Other Strategies •  folate, B6, B12 ( Homocysteine) •  w-3 FAs ( TG and VLDL,  platelet aggregation/clotting,  BP) •  soluble fiber intake •  intake of soy products • approved health claim, must have over 6 gram per serving to make claim • 25 g/day will lower LDL-cholesterol levels by about 5-12%

  24. Plant Sterols/Stanols • Naturally present in vegetable oils, nuts, cereals, beans • “Benecol” margarine produced by Finnish company/”Take Control” • Sterols/stanols interfere with dietary and biliary cholesterol absorption •  TC,  LDL • May complement statin therapy • Alcohol

  25. CABG: Coronary Artery Bypass Graft: vein from leg or artery from chest is used to alter blood flow around a diseased vessel. New vessels are still subject to atherosclerosis. • Carotid endarterectomy: surgical removal of plaque in carotid artery to prevent stroke. • Coronary Angioplasty: balloon catheter is inserted through an artery in the groin and is guided into the narrowed coronary artery. The balloon is inflated and compresses plaque back onto the arterial wall to allow better blood flow. Restenosis of artery is common.

  26. Holistic treatment: • Dean Ornish’s program shown to reverse atherosclerotic plaque. Radical: includes extremely lowfat/low chol. diet (10-15% fat, 5mg cholesterol, vegetarian) in conjunction with conventional treatment, exercise, stress management, smoking cessation. His studies showed pts had less plaque after 1 year (via angiogram) and had lower BP and lipid levels.

  27. Congestive Heart Failure • Congestive Heart Failure (CHF) • heart loses ability to provide adequate blood flow to the rest of the body • tries to compensate by increasing in size, increasing force of contraction, increasing HR • reduced blood flow to kidneys stimulates kidneys to conserve Na and H2O • As heart fails, blood begins to pool in the pulmonary veins and capillaries  pulmonary edema (ergo “congestion”)

  28. Cardiac Cachexia: Chronic PEM 2heart disease •  nutrient needs 2  work of heart and lungs • Poor delivery of nutrients/oxygen to tissues • Repeated respiratory infections • Anorexia, nausea, altered taste, physical exhaustion • Edema may mask weight loss until severe • PEM  weakening of heart/lungs;  infections

  29. Nutrition Therapy: Don’t overfeed! • Increases cardiac workload • Safe rate of weight loss if indicated (not if PEM, of course) • Sodium restriction proportionate to fluid retention • Fiber: avoid constipation; straining increases cardiac work

  30. HypertensionNew Blood Pressure Cutoffs (2003) Normal: <120/<80 mm Hg Prehypertension: 120-139/80-89 mm Hg Stage 1 hypertension: 140-159/90-99 mm Hg Stage 2 hypertension: >160/>100 mm Hg

  31. Essential or Primary Hypertension: • No identifiable cause • Secondary Hypertension: • Due to underlying disease such as kidney disease • White-coat Hypertension: • Caused by anxiety in a hospital setting. Spanish study reports as many as 2 in 5 diagnoses!

  32. Consequences • CHF • Kidney disease • Peripheral vascular disease • Stroke • Impaired vision/blindness

  33. Risk Factors for HypertensionUncontrollable 1. Age 2. Heredity African Americans: 4x death rate vs. whites 3. Family history

  34. Risk FactorsControllable/Modifiable • Overweight/Obesity • Smoking • Excessive EtOH • Sodium intake 2400mg = 6g (1tsp) table salt • Other minerals: Adequate K+does lower blood pressure. Inadequate data that Ca and Mg supplementsI prevent HTN. K+: fruits, vegetables, dairy foods, and fish.

  35. Prevention/Treatment of Hypertension 1. Follow a healthy eating pattern DASH diet Dietary Approaches to Stop Hypertension

  36. DASH: Dietary Approaches to Stop Hypertension • Diet high in fruits, vegetables, and nonfat dairy • Low in fat, saturated fat, and cholesterol • Sodium • Potassium • (Calcium and Magnesium) • Alcohol • Exercise • Obesity/Weight Management

  37. 1st DASH study • 133 subjects with mild hypertension • 326 subjects with normal blood pressure • 8 week study 1) control diet: average levels of fat/cholesterol; below average levels of K, Ca, Mg 2) fruit and vegetable diet: same as control diet but had 8-10 servings of fruit/veges (hi in K, Mg and fiber) 3) combination diet: Cut fat and cholesterol, high fruit/vege, high in low-fat dairy (Ca-rich)

  38. Results • Lowest blood pressure on DASH diet

  39. 2nd DASH sodium Trial • 412 subjects (120-159/80-95) • 2 weeks of typical American high-Na diet then 30 day intervention • Then typical diet or DASH diet with 1) 3300 mg Na 2) 2400 mg Na 3) 1500 mg Na

  40. Findings • Lower sodium correlated with lower blood pressure • Best results: DASH diet with 1500 mg Na+

  41. 2. Exercise • Several studies show exercise lowers blood pressure (by about 10 mmHg) • How?

  42. How? Not clear but may -  peripheral resistance -  serum catecholamine ( SNS response) -  renin activity (renin activates angiotensin/aldosterone -  Na retention) -  central fat (?)/  insulin levels

  43. Guidelines for Exercise Stage 1 Hypertension: • 50-85% of VO2 max for 20-60 minutes 3-5 days per week Stage 2 Hypertension: • 40-70% of VO2 max for 20-60 minutes 3-5 days per week

  44. Resistance Exercise: • Mild to moderate is OK (30-60% of maximal effort)

  45. Drugs • Diuretics • beta-blockers • (atenolol, metoprolol, propranolol) act as competitive antagonists at the adrenergic beta receptors

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