Transcript Unit # 5 Cardiovascular Disease

Unit # 5 Cardiovascular Disease
Cardiovascular Disease Overview
• #1 cause of mortality in Canada and the world
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
http://hcd2.bupa.co.uk/images/factsheets/cardiovascular_427x500.jpg
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 Atherosclerosis
 1. Begins with a lesion (injury) to the inner wall of
the artery. This is typically caused by ____________
or _________________
 2. Dietary _________________is converted into
cholesterol, which can be carried in the blood by a
type of lipoprotein called low-density lipoprotein
(LDL; aka ‘bad cholesterol’)
Development of Atherosclerosis
• 3. This LDL become oxidized by free radicals
in the blood stream. This oxidized LDL (ox-LDL)
causes further damage to the artery wall,
while calcium, cellular waste and platelets get
deposited into the area
Development of Atherosclerosis
• 4. Macrophages infiltrate the area to try to
repair the damage by absorbing the ox-LDL
• 5. These macrophages then become enlarged
foam cells, which cannot process the ox-LDL
Development of Atherosclerosis
• 6. The foam cells then rupture, depositing
more ox-LDL into the artery wall, narrowing it
Development of Atherosclerosis
• 7. More macrophages are then recruited to
help with the damage, leading to more
deposition of ox-LDL. This area narrowed by
cholesterol is called a __________
• 8. Smooth muscle cells on the artery wall then
form a hard cover over the inflamed area,
narrowing the artery
Picro Sirius staining for collagen of atherosclerotic cross-sections
Healthy artery
Lesion
Smooth muscle cells
Plaque filled with ox-LDL,
debris, calcium and
platelets
Pasterkamp, G. et al. J Am Coll Cardiol 2000;36:13-21
Copyright ©2000 American College of Cardiology Foundation. Restrictions may apply.
Major Consequences of
Atherosclerosis
 1. 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
Atherosclerosis
• 2. Atherosclerosis can cause an aneurism, a
dilation of the artery, which can eventually
rupture, leaking blood into the surroundings
(haemorrhage)
Major Consequences of
Atherosclerosis
 3. Atherosclerosis reduces blood flow and can
completely block blood flow if a thrombus
(blood clot) gets lodged there
Myocardial Infarction (MI)
 A myocardial Infarction (heart attack) can
occur when there is an absence of blood flow
to the heart. This is most often caused by
coronary artery disease (atherosclerosis of an
artery in the heart)
Warning signs of an MI
• Pain
– Sudden; constant pain in the chest, neck, jaw, shoulder, arms or
pack
– Pain feels like burning, squeezing, heaviness, tightness, pressure
• Shortness of breath
• Nausea
– Indigestion, vomiting
• Sweating
• Fear
– Anxiety, denial
Responding to the signs of an MI
• CALL 911!
• All activity should be stopped, lie/sit
comfortably
• If chest pain is experienced, swallow a 325mg
tablet of Aspirin (acetylsalicylic acid; thins
blood)
• If you take nitro-glycerine, take normal dosage
• Patient should rest comfortably and wait for
emergency response
• CPR can be performed by a trained person
Stroke
• Ischemic strokes: (80%) caused by lack of blood flow
to brain typically due to thrombus + atherosclerosis
– 1. Thrombotic stroke:
• Thrombus starts in artery near brain
– 2. Embolic stroke:
• Thrombus develops somewhere else
in body and travels to the brain
• A transient ischemic attack (TIA)
Is caused by a temporary disruption of blood flow to
brain; ‘mini-stroke’; warning sign
Stroke
• Hemorrhagic stroke: (20%) are caused by
uncontrolled bleeding in the brain
– Disrupts normal blood flow, kills brain cells
– Can be caused by weakness of the artery wall
• Aneurysm: weakened vessel full of blood
• Arteriovenous malformation (AVM): malformed blood
vessels in the brain that make the artery weak; typically
present at birth
5 Stroke Warning Signs
• Weakness- sudden loss of strength, numb
face, arms of legs
• Trouble speaking- both understanding and
speaking
• Vision problems
• Headache
• Dizziness
Stroke Response
• CALL 911!
• Patient should rest comfortably
• TIME is the most important factor in stroke
recovery. For most cases of stroke, a patient
has a narrow window of time (60 minutes) to
get to the hospital to minimize its lasting
effects
CVD RISK FACTORS
The Framingham Study:
Identifying the risk factors for CVD
• Begun in 1948 in Framingham, Mass
•
•
•
•
5000+ volunteers
On 3rd generation now!
Monitored at 2-year intervals
Made associations between CVD death and
lifestyle behaviours/ non-changeable factors
• Coined term “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
– Recall: ox-LDL deposits in artery walls, forms plaque
• HDL = “good” cholesterol
– Lowers ox-LDL deposition in artery walls!
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
diabetes
 Diabetes Mellitus: impaired ability of the blood to
store glucose (sugar)
Other risk factors for CVD
 Stress: increases blood pressure, increases blood
clotting, can increase cholesterol levels
 Low Omega-3 fatty acid intake: found in cold
water fish fat, inverse correlation with CVD
 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.
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)
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
http://cardiophile.org/wp-content/uploads/2008/11/scout-scan-of-pacemaker.jpg
Treatment of CVD
Coronary 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 CVD
 Drugs: 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! Take only if
prescribed by doctor
• Cardiopulmonary resuscitation (CPR) training of
many individuals