S4: Ageing Heart and Lungs

Question 1

Define healthy ageing

Answer 1

Process of developing and maintaining the functional ability that enables wellbeing in older age (WHO)

Question 2

Describe functional ability

Answer 2

Functional ability is about having the capabilities that enable all the people to be and do what they have reason to value. This includes a person’s ability to :

• Meet their basic needs.
• To learn, grow and make decisions.
• To be mobile.
• To build and maintain relationships .
• To contribute to society.

Question 3

Describe primary ageing

Answer 3

• Postulated to reflect and intrinsic, genetically pre-programmed limit on cellular longevity.
• Hayflick Phenomenon - cells have a finite ability to replicate and at a certain point they cannot and then undergo apoptosis.
• Seems to account for the relatively constant maximum life span in all animal species.

Question 4

Describe secondary ageing

Answer 4

• Due to the accumulated effects of environmental insults, disease and trauma over a lifespan.
• It seems to explain the variability in life span of individuals of a species.

Question 5

Describe normal heart and functions of CVS system

Answer 5

• Made up of muscle, valves and electrical conduction system.
• Dual chamber pump.
• Figure of 8 circulation system from heart –>. Lungs –> heart –> body.
• It is the body’s major transport system made up of the heart, arteries and veins.
• It delivers oxygenated blood, nutrients and chemical signals to the organs and tissues.
• It also transports waste products for elimination.

Question 6

List normal structural (anatomical) changes in CVS with age

Answer 6

Changes occur in:

• Heart muscle
• Heart valves
• Conduction pathways
• Arteries and veins

Question 7

List normal physiological changes in CVS with age

Answer 7

• HR
• BP
• Myocardial function
• CO
• Valvular function
• Endothelial function
  Conduction pathways

Question 8

Describe anatomical changes to heart muscle with age

Answer 8

Increase in left ventricular wall thickness due to:
- Increase myocyte size.
- Deposition of fibrous tissue (scarring of the muscle).
- Deposition of Amyloid.
There is also enlargement of the L atrium and slight enlargement and hypertrophy of left ventricular cavity in older.

Question 9

Describe anatomical changes to heart valves with age

Answer 9

• Increased thickness.
• Decreased flexibility.
• Calcification.
  This puts more strain on heart as different valves need to overcome pressure of other valves not working as well.

Question 10

Describe physiological changes to heart valves with age

Answer 10

Systolic and diastolic murmurs may result from thickened, calcified and maligned valve leaflets.
The heart may have to generate higher pressure in heart to push blood pass the valves. This is worse if individual has high afterload.

Question 11

Describe anatomical changes to conduction pathway in heart with age

Answer 11

• Decreased number of pacemaker cells (SA node cells and 50-75% lost by age 50).
• Fibrous tissue infiltration of conductive system which can cause conduction delays.
• Number of cells in AV node remain constant. This is probably because these are blocking cells rather the cells generating the electrical potential which tend to get worn out at a faster rate.

Question 12

Describe physiological changes to conduction pathway in heart with age

Answer 12

Irritability of the myocardium may result in extra systoles along with sinus arrhythmias and sinus bradycardia.

Question 13

Describe anatomical changes with arteries with ageing

Answer 13

• Arteries are elastic and compliant at birth.
• During systole when blood is ejected into the circulation, the arteries stretch reducing the resistance to blood flow. Capacitance when younger gives us the ability to react faster to problems CVS encounters e.g. Low BP arteries and veins can contract to increase vascular resistance to push blood around the body.
  With age:
• Blood vessels lose their elasticity and compliance with age. They lose muscle tissue (elastic quality) and more connective tissue (not much functional capacity).
• Lining of vessels problems starts in 20s e.g. plaque development, cholesterol development, atherosclerosis disease.
• Peripheral arteries less resilient.
• Larger arteries stiffer and less elastic and difficult to dilate.
• Calcifications in artery walls including aorta.

Question 14

Describe changes in aorta with ageing

Answer 14

• May become dilated, elongated and rigid.
• Stiffness affects the afterload of heart putting a lot of pressure on L ventricle.
• May develop calcifications and become tortuous
  Decreased elastin + increased collagen = calcification = increased stiffness + decreased compliance.

Question 15

Describe anatomical changes in veins with ageing

Answer 15

Veins dilate and stretch with decreased elasticity:

• Intima and muscular walls thicken and become less elastic.
• Veins lose functional ability e.g. varicosities.

Question 16

Describe physiological heart rate changes with age

Answer 16

• Decreased cardiac responsiveness rate with exercise.
• Heart may take longer to return to baseline rate
• Linear decrease in the maximal heart rate achievable during exercise with age.
• With age, the supine resting heart rate does not change in healthy men.
• However, ability to increase heart rate reduces significantly e.g. During excersize.

Question 17

Describe physiological changes in BP in age

Answer 17

Systolic blood pressure may rise disproportionately higher than diastolic BP.
This can cause microvascular damage to blood vessels (narrowing and blockage) especially at end arteries in eyes and brain due to uncontrolled hypertension.

Question 18

List 3 changes in myocardial function with age

Answer 18

Decreased contractile strength and efficiency

Decreased cardiac output

Decreased cardiac reserve to recover

Question 19

Describe physiological changes in CO in age

Answer 19

Decreased CO in response to excersize or stress.

No change at rest as not under strain.

Question 20

Describe physiological changes in cardiac function (preload and afterload) with age

Answer 20

Preload:
- Early diastolic left ventricular filling rate progressively slows with age.
- Late diastole is greater because of increased atrial contraction.
- End diastolic volume in supine or seated position is not usually decreased in a healthy older patient.
Afterload:
- Decrease in elasticity and lumen diameter within the arterial tree leads to a gradual increased systolic blood pressure (more strain in LV to push blood out increasing back pressure)with age.
- Small arteries and arterioles become less responsive to vasodilator cues with age, further increasing peripheral resistance.

Question 21

List changes in left ventricle with ageing

Answer 21

• Concentric hypertrophy.
• Aortic valvulopathy.
• Decreased heart rate variability.
• Diastolic dysfunction.
• Conduction abnormalities.
• Mitral annular calcification.

Question 22

Describe diastolic dysfunction, diastolic abnormality , diastolic heart failure

Answer 22

• Diastolic abnormality is most mild e.g. abnormal relaxation, abnormal early filling with normal exercise tolerance.
• Diastolic dysfunction/HF-PEF in elderly –> ability of heart to fully relax to fill ventricles with blood decreases (problem in higher HR). there is reduced exercise tolerance.It is heart failure with preserved ejection fraction (in echogram).
• Diastolic heart failure: HF with reduced ejection fraction.

Question 23

Describe changes in ejection fraction with age

Answer 23

On increased exertion, the ejection fraction is reduced due to a number of factors:

• Increased vascular resistance.
• Increased EDV.
• Decreased maximal myocardial contractility.
• Decreased contractility by adrenergic NS stimulation.

Question 24

What are the functional implications of normal age related changes of CVS?

Answer 24

They are influenced by presence of disease and lifestyle variations (secondary ageing). Implications:

• Decreased response to stress.
• Activity intolerance.
• Orthostatic hypotension –> Blood vessels are too thick and when standing they cannot change in size for BF.

Question 25

Relationship between cardiac ageing and excersize

Answer 25

- Peak exercise capacity and peak oxygen consumption decreases with age. - Aerobic capacity decreases by 50% between ages 20 and 80. - There is a decreased stress response with age.

Question 26

Summary of cardiovascular ageing and their consequences

Answer 26

- Decreased elasticity - Decreased compliance - Atherosclerosis - Vascular stiffness and thickening - Endothelial dysfunction - Alterations in conduction tissue - Fibrosis - Increase in LV mass - Calcification - Amyloid deposition Consequences - Higher BP - Ischaemic heart disease - Myocardial infarction - Heart failure - Arrhythmias - Stroke

Question 27

Modifiable CV risk factors

Answer 27

``` BP (most important!) Diabetes mellitus Dyslipidemia Smoking Physical inactivity Obesity Stress Post menopausal hormone therapy Excess alcohol intake ```

Question 28

What are the important roles of respiratory system?

Answer 28

- Major role is in gaseous exchange (O2, CO2). Also involved in: - Acid base homeostasis. - Control of BP. - Important role in non specific immune responses.

Question 29

What are the anatomical changes in respiratory ageing?

Answer 29

- Loss of elasticity of rib cage (stiffer due to calcification, reduced amount of connective tissue). - Kyphosis. - Diaphragm falls in height thereby reducing its ability to generate force. - Lung parenchyma: loss of elasticity, alveolar degeneration, increasing air trapping (non functional air not being moved), reduced clearance of surface material secretions from small airways.

Question 30

What are the lung functional changes in respiratory ageing?

Answer 30

- Reduced residual volume. - Increased dead space. - Reduced gas exchange, lung perfusion, resting plasma oxygen, loss of central autoregulation from CNS leading to a reduced response to hypoxia and hypercarbia.

Question 31

Describe the structural changes with lung

Answer 31

- Decrease in elastic recoil - Alveolar sacs become shallower, decreased alveolar surface are by 15% by the age of 70. - Increased diameter of the respiratory bronchioles and alveolar ducts. - Changes result in premature closure of small airways during normal breathing which can cause air trapping and hyperinflation ('senile emphysema').

Question 32

Describe age associated changes in the chest wall

Answer 32

With ageing there is reduction in chest wall compliance due to: - Stiffening of the thoracic cage from calcification of the rib cage. - Age related kyphosis. - Arthritis of costovertebral joint. Therefore more muscular work is therefore required for ventilation and (20% more at 60 years vs 20 years) and increased work for breathing.

Question 33

Describe kyphosis in age

Answer 33

- Kyphosis is collapsed curvature of spine. If not dealt with straight away it continues to progress. - Severe kyphosis --> oxygen needed at rest. This is because it can compress thorax reducing size it can expand. - 43% in 75-93 years old. Some causes of kyphosis: - Vertebral fractures (can be treated). - Decreased intervertebral disc space. - Osteoporosis --> collapsed vertebrae.

Question 34

Describe anatomical changes in respiratory muscles with age

Answer 34

Reduction in respiratory muscle strength in healthy elderly subjects: - Muscle atrophy. - Decrease in fast twitch fibres. Predisposes individuals to diaphragmatic fatigue, higher work for breathing and ventilatory failure with increased ventilatory load

Question 35

Describe functional changes in respiratory muscles with age

Answer 35

Respiratory muscle performance is impaired by the age related increased in functional residual capacity. - Closely related to nutritional status. - MIP and MEP correlate with lead body mass (LBM). They are measures of diaphragmatic power and their ability to force air in and out. Demonstrates older you get, the less functional and weaker diaphragm is. MVV significantly lower in undernourished subjects - Necroscopic studies: correlation with LBM and diaphragmatic muscle mass.

Question 36

Functional changes in the lungs with age with the following measures : RV, VC, TLC, gas exchange and ppO2

Answer 36

1. Residual volume (RV): Air remaining in the lungs following a full and forced expiration. Increased with age due to loss of lung elasticity and air trapping. 2. Vital capacity (VC): Total volume of air that can be exhaled. Decreased with age due to chest wall rigidity and reduced respiratory muscle strength. 3. Total lung capacity (TLC): Total volume of air within the lungs following a full inspiration. No change in age due to loss of elasticity counterbalanced by chest wall rigidity. 4. Gas Exchange: The diffusion of gases from an area of higher concentration to an area of lower concentration. Reduced is age due to decreased alveolar surface area and increased ventilation/perfusion mismatch. 5. Partial Pressure of Oxygen: The part of total blood gas pressure exerted by oxygen gas. Reduced in age due to decreased alveolar surface area, decreased gas exchange and increased ventilation/perfusion mismatch.

Question 37

Describe changes in spirometry with age

Answer 37

``` FEV1 and FVC Increased up to: - 20 years in females. - 26 years in males. Then annual decrease of: - 29 ml (25-39). - 38 ml (>65). Particularly accelerated loss after 70 years. ```

Question 38

Changes in static pressure volume curve with age

Answer 38

Shifts left with steeper curve in age. Older --> harder to get air in and out.

Question 39

Describe vascular remodelling in lungs with age

Answer 39

Age related remodelling of pulmonary vasculature results in: - Increased pulmonary vascular stiffness. - Increased vascular pressure and resistance. - Decreased pulmonary capillary blood volume. These can put pressure on right side of the heart.

Question 40

Describe immunological changes to lungs in ageing

Answer 40

Increased risk of respiratory tract infections due to: - Decreased mucociliary transport.. - Blunted cough reflex. - Increased swallowing problems. - Decreased in number and function of T cells and macrophages. Ageing lungs may be subject to chronic low grade inflammation in the absence of overt lung disease. Bronchoalveolar lavage has demonstrated increased levels of neutrophils. IL-1 and IL-8 as well as neutrophil elastase. Thought to be related to long standing exposures to atmospheric particles and pollutants, including passive smoking. Problem with chronic inflammation in alveoli: - Swelling of alveoli. - Disruption of interaction between blood vessel which affects gas exchange

Question 41

Relationship between respiratory ageing and excersize

Answer 41

- Excersize capacity is highly variable. - VO2 max (maximum oxygen consumption) is 'an objective surrogate of fitness' decrease by a rate of about 1% a year. - Increased decline seen in more sedentary individuals. - Depends upon individuals fitness levels.