L1: Cardiovascular Disease Flashcards
What percentage of UK deaths is attributable to CVD in 2018?
27%
What where the two experiments to identify the association between physical activity and CHD?
Morris et al, 1980: London bus conductors
Paffenbarger 1975: Work intensity
What curve does volume of physical activity follow as a risk factor for CVD mortality?
U-shaped curve
What range of physical activity (Met hours per week) is associated with the lowest risk of CVD mortality and what is the risk reduction?
15 - 40 MET hours per week reduces the risk of mortality from CVD by 42% compared to sedentary people
Other than physical activity, what other modifiable risk factor for CVD mortality is there>
Cardiorespiratory fitness
Who identified the association between cardiorespiratory fitness and CVD mortality?
Barlow et al
What reduction in risk is associated with a 1 MET increase in cardiorespiratory fitness?
18% CVD mortality reduction
What did Tikkenan et al, 2018 identify?
- Cardiorespiratory fitness is capable of reducing the risk caused by high genetic risk.
- Those with high cardiorespiratory fitness reduced there risk below 1 despite having high genetic risk.
What are the three layers of arteries?
Tunica intima, Tunica media and tunica externa
What is the tunica intima?
Inner muscular layer which contains a layer of endothelial cells
What is the Tunica Media?
Smooth muscular layer responsible for vasoconstriction and vasodilation
What is the Tunica Externa
Connective tissue composed of mainly collagen and elastin responsible for providing structure and support.
Describe the process of Atherosclerosis formation
1) Damage to the endothelial lining of blood vessels leads to increased permeability between the blood and vessel wall.
2) Increased diffusion of LDLs and VLDLs into the tunica media.
3) Immune response recruits circulating monocytes which differentiate into macrophages.
4) Macrophages engulf lipid molecules becoming foam cells which contribute to the formation of fatty streaks
5) Smooth muscle cells migrate and proliferate and collagen deposition occurs ultimately producing an advance fibrous cap lesion.
6) The AFC causes a thrombus that can either rupture causing an haemorrhage or break off causing a clot. This can lead to a myocardial infarction or stroke.
What causes damage to the endothelial lining?
1) High blood pressure
2) Diabetes
3) High cholesterol
4) Smoking
5) Chronic low grade inflammation
What is the clinical identification of CVD?
40% reduction in blood flow identifies as cardiovascular disease
When does atherosclerosis begin developing and how does this effect primary intervention?
Development has been identified in very early ages and so primary intervention needs to occur early in life.
What are other risk factors for Cardiovascular Disease?
- Physical inactivity/activity
- Lipid metabolism
- Blood pressure
- Vascular function
- Inflammation
How is physical inactivity a modifiable risk factor?
- Physical inactivity reduces GLUT-4 recruitment in muscle cells. GLUT-4 receptors are responsible for Glucose uptake, meaning the more insulin is required for a given glucose uptake.
- Physical inactivity leads to elevated blood pressure which increase arterial stress and contributes to endothelial damage.
What are chylomicrons?
Transport molecules responsible for the transport of dietary triglycerides from the small intestines to peripheral adipose.
What do VLDL do?
Transport of endogenous triglycerides from the liver to peripheral adipocytes
What do LDL do?
Transport of cholesterol around the body
What does HDL do?
Transport and removal of cholesterol from circulation
What to lipid transport molecules can provide protective benefits against cardiovascular disease?
VLDL reduces in response to exercise which prevents the over accumulation of adipocytes and the development of chronic inflammation.
HDL increases in response to exercise which increases the removal of cholesterol from the circulating blood, reducing the effect of cholesterol of endothelial dysfunction and damage.
How can acute and chronic exercise modify blood pressure and subsequently cardiovascular disease risk?
Acute
transient Reduction in systolic blood pressure hours after exercise caused by increased endothelial-dependent vasodilation. Vasodilation occurs in response to increased vascular resistance from exercise.
Arterial baroreflex resetting occurs which reduces parasympathetic nerve activity meaning reduced epinephrine responsible for vasoconstriction. Subsequently, vasodilation increases.
Chronic
chronic exercise promotes IL-10 anti-inflammatory cytokine release whilst decreasing IL-6 and TNF-Alpha thus changing the inflammatory profile of the body.
Angiogenesis occurs along with increase lumen size of blood vessels resulting in increased cross-sectional area. Wall thickness is also reduced and overall blood pressure is lower.
