Unit # 5 Cardiovascular Disease

Cardiovascular Disease Overview

• #1 cause of mortality in Canada

Laboratory Centre for Disease Control; Statistics Canada, 1997

Cardiovascular Disease Overview

• Refers to diseases of the heart (“cardio”) and blood vessels (“vascular”)

• Typically affects – the ability of the heart to pump or – the ability of the blood vessels to deliver blood

• Arteries bring 02/nutrient rich blood to where it is required

• Coronary arteries provide the heart with blood

Cardiovascular System

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Major forms of Cardiovascular Disease (CVD)

• Atherosclerosis: progressive narrowing of the arteries typically caused by fatty deposits

• Coronary Artery Disease (CAD)/ coronary heart disease (CHD): atherosclerosis of the coronary artery

• Heart Failure

• Hypertension (high blood pressure)

• Cerebrovascular disease

Atherosclerosis

Development of Atherosclerosis1. Begins with a lesion (injury) to the inner wall of

the artery

2. Dietary saturated fat is converted into cholesterol, which is carried by lipoproteins in the blood

Development of Atherosclerosis

3. The LDL (low-density lipoproteins) and VLDL (very low-density lipoproteins) forms of cholesterol, as well as other fatty substances can deposit in the artery wall

Development of Atherosclerosis

4. Over time, this cholesterol is replaced with calcium and other deposits. This calcified area is now known as a plaqueAt this point, the damage is irreversible

Copyright ©2000 American College of Cardiology Foundation. Restrictions may apply.

Pasterkamp, G. et al. J Am Coll Cardiol 2000;36:13-21

Picro Sirius staining for collagen of atherosclerotic cross-sections

Major Consequences of Atherosclerosis

Atherosclerosis can reduce the elasticity of the arteries, making them less able to respond to demand and putting more strain on the heart

Major Consequences of Atheroscleorsis

Atherosclerosis reduces blood flow and can completely block blood flow if a thrombus (blood clot) gets lodged there

Thrombus + AtherosclerosisIf this happens in the coronary arteries, a

myocardial infarction (heart attack) may occur

If this happens in an important artery in the brain, a stroke may occur

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Acute CVD consequences

• Angina pectoris is caused by temporary lack of oxygen to the heart. – Symptoms include: chest, arm and neck pain

• A transient ischemic attack (TIA) is when the brain is temporarily deprived of oxygen– Symptoms include headache, dizziness, loss of

consciousness, inability to speak

CVD RISK FACTORS

CVD Risk Factors

• Major Changeable– Hypertension, high blood cholesterol, tobacco

smoke, physical inactivity, obesity, diabetes

• Minor Changeable– Stress, low omega-3 FA, high alcohol consumption

• Non-Changeable– Age, male gender, heredity, ethnicity

Major Changeable CVD Risk Factors

• Hypertension = high arterial blood pressure– Can cause damage to blood vessels, put extra

strain on the heart– Cause of hypertension can be unknown. However,

high body fat, high salt intake, lack of exercise are known risk factors

Major Changeable CVD Risk Factors

• High serum (blood) cholesterol– Typically caused by eating too much saturated fat– Can deposit in artery walls

• LDL/VLDL = “bad” cholesterol• HDL = “good” cholesterol

Major Changeable CVD Risk Factors

• Tobacco smoke• Nicotine can cause lesions in the artery wall• Carbon monoxide in cigarette smoke is doubly

damaging– causes lesions in the artery wall – decreases the ability of the blood to transport

oxygen

Major Changeable CVD Risk Factors

Physical Inactivity: exercise can lower blood pressure, increase HDL and lower LDL and VLDL, reduce stress, maintain body weight and control type II Diabetes.

• Obesity/overweight, especially abdominal obesity– Can lead to hypertension, low HDL, type II

diabetesDiabetes Mellitus: impaired ability of the blood to

store glucose (sugar)

Major non-changeable risk factors for CVD

Age : the older you are, the higher the risk

Gender: males are at higher risk than females. Biological difference or cultural difference?

Heredity

Ethnicity: Higher risk in African Canadians, Latinos, Aboriginals and South Asians

Worldwide Age-Standardized Mortality Rates for CVD (WHO, 1995)

Other risk factors for CVDStress: increases blood pressure, increases blood

clotting, can increase cholesterol levels

Low Omega-3 fatty acid intake: found in cold water fish fat.

Alcohol: low daily intake (1-2 glasses per day) of alcohol has been associated with lower risk of CVD! However, high intake can damage the heart muscle and increase CVD risk.

Prevention of CVD:Primary vs. Secondary Prevention

• Primary prevention looks to reduce risk factors to prevent a disease before it starts– Ex’s:

• Secondary prevention focuses on treatment and early detection to prevent morbidity and mortality after a disease has started– Ex’s:

Treatment of CVD• The decline in the cases of CVD-related deaths

in North America is mainly due to medical advances such as– Heart transplants

– Artificial hearts: now used as a bridge during surgery, possible permanent devices in the future

– Implanted pacemakers

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Treatment of CVDCoronary artery bypass surgery: replacing blocked/ narrow coronary arteries with healthy segments of other arteries

Treatment of CVD

Angioplasty: enlarging an artery by using a balloon-type instrument

Treatment of CVDDrugs: target lowering blood pressure,

reducing blood cholesterol, opening blood vessels, stabilizing heart rhythm

Improvements in ambulance service and emergency room care

Cardiac rehabilitation programs

Treatment of CVD• Public education and motivation campaigns

• Screening

• Aspirin: decreases tendency of blood to clot. Side effects can be serious!

• Cardiopulmonary resuscitation (CPR) training of many individuals