CVD risk factors and risk stratification in primary and secondary prevention Flashcards
Risk factors
characteristic or behaviour increasing a person’s likelihood of developing a disease
Risk Factor model vs. risk marker model
Factor model - risk factor and marker cause atherosclerosis
Marker model - markers given off from atherosclerosis and risk factors
Primordial prevention
population-based strategies applied at all stages along the chronic disease spectrum to reduce the incidence and prevalence of risk factors for chronic disease(s); examples include beneficial changes in behaviour, the built environment, socioeconomics, and health care policy
Primary prevention
population and individual-based strategies applied before a disease is diagnosed in order to prevent disease occurrence; this includes effective screening and aggressive case finding, primordial prevention tactics, and in some cases, the judicious use of pharmacotherapy
Secondary prevention
population and individual based strategy applied to diagnosed chronic disease states in early stages to reduce the general impact or morbidity of the disease; modalities generally include regular medical examinations, effective diagnostic testing, lifestyle medicine, and when needed, pharmacotherapy
Global (absolute) risk assessment
Probability of developing CVD within a defined period of time, taking into account several risk factors simultaneously and recognising the multifactorial nature of this group of diseases ØIn primary prevention a 10yr risk score is calculated ØIn secondary prevention risk of a serious event within 14yrsis usually utilised
Relative Risk
- Relative risk is the ratio of the absolute risk of a given patient (or group) to that of a low-risk group.
- Literally, the term relative risk represents the ratio of the incidence in the exposed population divided by the incidence in unexposed persons.
- The denominator of the ratio can be either the average risk of the entire population or the risk of a group devoid of risk factors.
INTERHEART study (Sign, 2007)
Nine measured and potentially modifiable risk factors, accounted for more than 90% of the proportion of the risk for acute myocardial infarction.
Smoking, history of hypertension or diabetes, waist-to-hip ratio, dietary pattern, physical activity, alcohol consumption, blood apolipoproteins and psychosocial factors were identified as the key risk factors.
Worldwide, the two most important modifiable cardiovascular risk factors are smoking and abnormal lipids. Hypertension, diabetes, psychosocial factors and abdominal obesity are the next most important but their relative effects vary in different regions of the world.
What is cholesterol?
About 20% of total daily cholesterol production occurs in the liver; other sites of higher synthesis rates include the intestines, adrenal glands, and reproductive organs.
• HDL and LDL are not types of cholesterol but rather lipoproteins which are cholesterol (and triglyceride) transporters
• Each consists of a lipid portion (hydrophobic = water insoluble) and a protein portion (hydrophilic = water soluble)
Lipoprotein categories
Based on the proportions between the lipid portion (low density) and the protein portion (high density) lipoproteins vary in their overall density and size and are grouped into 4 categories:
ØChylomicrons (which transport triglycerides from the gut) after digestion ØVLDL –also transport TGs (from the liver rather than the gut) but have a larger amount of cholesterol than chylomicrons
ØIDL –intermediate density lipoproteins
ØLDL –low density lipoproteins –transporting cholesterol (and triglycerides) and making these available to cells ØHDL –high density lipoprotein –which is more than 50% protein and therefore has higher density than all the others –this is thought to mop up excess cholesterol (referred to as ‘reverse transport’)
CHD Risk According to HDL-C Levels Framingham Study
Lower HDL levels - higher CHD risk
Higher TC/HDL ratio - higher CHD risk
HDL protective function
- Ability of HDL to promote efflux of cholesterol from macrophages in the artery wall.
- Ability to inhibit vascular inflammation.
- HDL also has antioxidant and antithrombotic properties.
- They enhance endothelial function, promote endothelial repair, increase angiogenesis in ischaemia, and have recently been reported to have antidiabetic properties.
- It is currently not known which HDL component(s) and which HDL subpopulations are responsible for these potentially cardioprotective functions.
- Ability of HDL to promote efflux of cholesterol from macrophages in the artery wall.
- Ability to inhibit vascular inflammation.
- HDL also has antioxidant and antithrombotic properties.
- They enhance endothelial function, promote endothelial repair, increase angiogenesis in ischaemia, and have recently been reported to have antidiabetic properties.
- It is currently not known which HDL component(s) and which HDL subpopulations are responsible for these potentially cardioprotective functions.
Novel risk markers
• Lipids and lipoproteins ØTG, lipoprotein size, particle number, apoproteins
• Inflammatory markers ØCellular adhesion molecules (CAMs), cytokines (interleukins, tumour necrosis factor), hsCRP
• Other
ØHomocysteine, NT-proBNP, Troponin
• Prothrombotic markers ØFibrinogen, Plasminogen activator inhibitor-1
• Imaging techniques
ØCAC score (assesses atherosclerotic burden using CT scanning)
Secondary prevention treatment targets
Intensive statin therapy is recommended in all patients following MI in the absence of a contraindication or intolerance irrespetice of initial cholestorl values.
Stations should be prescribed with a lower is better approach to achieve values of at least <2.5mmol for non-HDL
