Week 4: Cardiovascular And Cerebrovascular Disorders Flashcards
Cardiovascular Changes with Aging: Heart
- Slight increase in the size of the heart (especially the left ventricle) is not uncommon (cardiomyopathy).
- Heart wall thickens and heart fills more slowly.
Cardiovascular Changes with Aging: Valves
Thicker and stiffer due to lipid deposits, collagen degeneration and fibrosis.
Cardiovascular Changes with Aging: Conductivity of the Heart
- SA node cells decrease in number as myocardial fat, collagen and elastin fibers increase.
- Results in slightly slower HR.
Cardiovascular Changes with Aging: Contractility of the Heart
Prolonged most likely due to slower release of calcium into the contractile portion of heart during systole.
Cardiovascular Changes with Aging: Blood Vessels
- Diminished elasticity d/t changes in collagen and elastin.
- Thickened vessel walls
- Pooling of blood increases venous pressure diminishing effectiveness of peripheral valves.
- Baroreceptors become less sensitive -> orthostatic hypotension
- Aorta becomes thicker, stiffer and less flexible
Thickened blood vessel walls are a result of
- Reorganization of cellular and extracellular matrix.
- Leads to slightly slower rate of exchange of nutrients and waste.
Baroreceptors
Monitors and makes changes to help maintain BP
Thicker, stiffer and less flexible aorta can result in
Higher BP and makes heart work harder which may lead to thinking of heart muscle (hypertrophy).
What are the effects of changes to the heart in older adults?
An older heart may not be able to pump blood as well when a patient makes it work harder.
Things that make the heart work harder include
Certain medications (NSAIDs) Emotional stress Physical exertion Illness Infections Injuries
Atherosclerosis
Beings as soft deposits of fat that harden with age.
Referred to as “hardening of the arteries”
Although atherosclerosis can occur in any artery in the body, the fatty deposits prefer
The coronary arteries.
What is a major cause of CAD?
Atherosclerosis; endothelial injury and inflammation play a major role in development.
C-reactive protein
- Nonspecific marker of inflammation.
- Increased in many patients with CAD.
Chronic exposure to C-reactive protein is linked with
Unstable plaques and oxidation of LDL cholesterol -> further contributing to atherosclerosis
Collateral Circulation
Arterial anastomoses or connections that exist within coronary circulation.
What are two factors that contribute to the growth and extent of collateral circulation?
- Inherited predisposition to develop new blood vessels (angiogenesis)
- Presence of chronic ischemia
Increases collateral circulation develops when
When plaque blocks the normal flow of blood through a coronary artery and the resulting ischemia is chronic.
When occlusion of the coronary arteries occurs slowly over a long period,
There is a greater chance of collateral circulation developing and the heart muscle may still receive adequate amount of blood and oxygen.
Collateral circulation development with rapid-onset CAD or coronary spasm
- With rapid-onset CAD or coronary spasm, time is inadequate for collateral circulation development.
- Consequently, a reduced blood flow results in more severe ischemia or infarction.
What are non-modifiable risk factors for CAD?
- Age
- Gender
- Ethnicity
- Family History
- Genetic Inheritance
Non-modifiable risk factors for CAD: Age/Gender
- After age 75, the incidence of serious heart events in men and women equalizes, although CAD causes more deaths in women than men.
- On average, women with CAD are older than men who have CAD and are more likely to have co-morbidities (i.e. hypertension, diabetes).
Non-modifiable risk factors for CAD: Ethnicity
African Americans have an earlier onset and more severe CAD than there CAD counterparts
Non-modifiable risk factors for CAD: Family history
Family history is a risk factor for CAD and MI. Often, patients with angina or MI can name a parent or sibling who has died of CAD.
What are major modifiable risk factors for CAD?
- HTN
- Elevate serum lipids
- Tobacco use/second-hand smoke
- Physical inactivity
- Obesity
Major modifiable risk factors for CAD: HTN
- Hypertension increases the risk of death from CAD 10-fold in all persons.
- The stress of an elevated BP increases the rate of atherosclerosis. This relates to the shearing stress that causes endothelial injury.
What is the goal BP in people older than 60 years of age?
less than 150/90 mmHg is recommended to prevent stroke, CAD and heart failure.
What is a high cholesterol level?
> 200 mg/dL
What is an elevated triglyceride level?
> 150 mg/dL
What is an abnormal range for high-density lipoproteins?
<50
What is an elevated low-density lipoprotein?
> 130
What are contributing modifiable risk factors for CAD?
- Diabetes
- Metabolic syndrome
- Substance abuse
- Stress
What drugs are used to treat CAD?
Lipid lowering agents: -Statins -Ezatimibe (Zetia) -Niacin Antiplatelets: -ASA -Clopidogrel (Plavix)
Statins: MOA
Inhabit cholesterol synthesis, decreases LDL and increases HDL
What should you monitor in patients taking statins?
Monitor for liver damage and myopathy. Therefore monitor liver enzymes and recheck with increased dosages.
Serious adverse effects of statins
Liver damage and myopathy that can progress to rhabdomyolysis (breakdown of skeletal muscle)
Ezatimibe (Zetia): MOA
Inhibits the absorption of dietary and biliary cholesterol across the intestinal wall.
Ezatimibe (Zetia) serves as
An adjunct to dietary changes, especially in patients with primary hypercholesterolemia.
Niacin: MOA
- Lowers LDL and triglyceride by inhibiting synthesis
- Increases HDL
Niacin: Side Effects
- Flushing*
- Pruritus
- GI side effects
- Orthostatic Hypotension
Aspirin use in older adults with CAD
- Unless contraindicated, low-dose aspirin is recommended.
- Considered in healthy women 60 years or older if BP is controlled and the benefit for MI prevention outweighs the risk of GI bleed or hemorrhagic stroke.
For high-risk women with CAD that are intolerant to aspirin, what can be used as a substitute?
Clopidogrel (Plavix)
What are necessary modifications to guidelines for physical activity in older adults?
- Longer warm-up
- Longer periods of low-level activity
- Longer rest periods
- Avoid extremes of temperature → heat intolerance results from a decreased ability to sweat
- 30 minutes most days minimum
Angina
When O2 demand of heart is greater than the O2 supply -> myocardial ischemia.
Myocardial ischemia occurs when
- Arteries are blocked 70% or more.
- 50% or more for left main coronary artery.
Chronic Stable Angina
Intermittent chest pain that occurs over a long period with same pattern of onset, duration and intensity of symptoms.
Chronic Stable Angina is provoked by
Physical exertion, stress, or emotional upset.
When patient’s are asked to describe chronic stable angina, they may
- Deny pain but describe a pressure, heaviness or discomfort in chest.
- Discomfort is often described as squeezing, heavy, tight or suffocating sensation.
How long does pain for chronic stable angina last for?
Lasts for only a few minutes and commonly subsides when the precipitating factor is resolved (resting, calming down, using sublingual NTG)
Goal of Chronic Stable Angina
↓ O2 demand and/or ↑ O2 supply
Short-acting nitrates: Nitroglycerin
- Dilate peripheral and coronary blood vessels
- Given via sublingual or oral spray.
- Can be used prophylactically
Frequency of taking Nitroglycerin
- One dose every 5 minutes with no more than 3 doses in 15 minutes
- If chest pain continues after 3rd dose call for emergency help or go to ER.
Nitroglycerin: Patient teaching
- Warn the patient that a headache, dizziness, or flushing may occur.
- Caution the patient to change positions slowly after NTG use because orthostatic hypotension may occur.
Long-acting nitrates
To reduce angina incidence
Main side effects of long-acting nitrates
Headache*
Orthostatic hypotension
Long-Acting nitrates: Methods of administration
- Oral [Isosorbide dinitrate (Isordil) or isosorbide mononitrate (Imdur)]
- Nitroglycerin (NTG) ointment [Nitropaste 2%]
- Transdermal controlled-release NTG
What are other medications that can be used to treat chronic stable angina?
- Beta-blockers
- CCB
- ACE inhibitors
- ARBs
Chronic Stable Angina Treatment: Beta-blockers
- Relief of angina symptoms.
- Patients who have LV dysfunction, elevated BP, or have had an MI should start and continue β-blockers indefinitely.
Calcium channel blockers to treat chronic stable angina
Used if beta-blockers are contraindicated or poorly tolerated.
Angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARBs) to treat chronic stable angina
- Result in vasodilation and reduced blood volume.
- Most important, they can prevent or reverse ventricular remodeling in patients who have had an MI.
Congestive Heart Failure
- An abnormal condition involving impaired cardiac pumping/filling.
- Heart is unable to produce an adequate cardiac output (CO) to meet the oxygen needs of the tissues.
CHF if characterized by:
- Ventricular dysfunction
- Reduced exercise tolerance
- Diminished quality of life
- Shortened life expectancy
Primary Risk Factors for CHF
- HTN
- CAD
Co-morbidities that contribute to development of CHF
Diabetes
Vascular disease
Advanced age
Primary causes of CHF
Conditions that directly damage the heart (CAD including MI, HTN, Rheumatic heart disease)
Precipitating causes of CHF
Conditions that increase workload of ventricles (Anemia, Infection, Nutritional deficiencies).
Systolic HF
Inability of the heart to pump blood effectively
Causes of Systolic HF
- Impaired contractile function (i.e. MI)
- Increased afterload (i.e. Hypertension)
- Cardiomyopathy
- Mechanical abnormalities (i.e. Valve disease)
Ejection Fraction
The amount of blood ejected from the left ventricle.
Hallmark finding of systolic failure is
A decrease in left ventricular ejection fraction.
Less than 45%, can be as low as 10%.
Normal Ejection Fraction
55%-60%
Diastolic HF
Impaired ability of the ventricles to relax and fill during diastole, resulting in decreased stroke volume and CO.