Clinical Risk Factors for IHD PDF

Ischaemic heart disease is myocardial oxygen starvation due to an imbalance in supply and demand, leading to cell death. Demand is increased by: -​ Wet Beri Beri (Vit B1 deficiency) -​ Cocaine -​ Left ventricular hypertrophy (from hypertension, aortic stenosis or steroid misuse) -​ Paget's...

Ischaemic heart disease is myocardial oxygen starvation due to an imbalance in supply and demand, leading to cell death. Demand is increased by: -​ Wet Beri Beri (Vit B1 deficiency) -​ Cocaine -​ Left ventricular hypertrophy (from hypertension, aortic stenosis or steroid misuse) -​ Paget's disease (affects bone renewal) -​ Thyrotoxicosis (excess thyroid hormone) -​ Tachydysrhythmia Supply is decreased by: -​ Anaemia -​ Aortic Valve stenosis -​ Atherosclerosis -​ Coronary artery spasm (from cocaine, inflammation or prinzmetal’s angina (temporary increase in vascular tone decreasing lumen diameter)) -​ Hypoxia -​ Hypovolaemia (decreased blood volume) -​ Tachydysrhythmia These are all risk factors for IHD. Risk Factor- Attribute, characteristic or exposure which increases an individual's likelihood of developing a disease or injury. Traditional Risk Factors of IHD: -​ Age- increased risk over time -​ Sex- higher risk in males -​ Smoking History -​ Hypertension -​ Hyperlipidaemia -​ Type 2 diabetes mellitus -​ Metabolic syndrome Clinical Risk Factors of IHD: -​ Acquired behaviours e.g. smoking -​ Inherited disorders e.g. Familial hyperlipidaemia -​ Complex disorders e.g. hypertension or Type 2 diabetes mellitus -​ Laboratory biomarkers e.g. hsCRP (indicates inflammation) Age Hypertension Naturally as we age, systolic pressure increases while diastolic decreases. Pulse pressure= Systolic-Diastolic Mean Arterial Pressure= ⅓ Systolic+ ⅔ Diastolic The wider pulse pressure may indicate less compliant and damaged vessels or even a leaky heart valve. Increased MAP indicates true hypertension This has a quantitative mortality, where the higher the pressure the worse the prognosis. There isn’t a true cut off between high and low blood pressure but there is a rough estimate: High blood pressure 140/90 mmHg, At risk 130/80 mmHg, Ideal between 90/60 and 120/80mmHg An increase in blood pressure also increases the risk of a stroke , when over 50, high systolic pressure increases risk of vascular dementia. Hypertension can be staged: Stage Systolic Pressure Diastolic Pressure Stage 1 140-159 90-100 Stage 2 160-180 90-100 Severe 180 >110 Stage 2 and severe are always treated however, stage 1 is treated if the person is under 80 and presents with at least one of the following: Target organ damage, cardiovascular disease, renal disease, diabetes mellitus , 10 year risk of IHD or Vascular dementia risk >20 years Every 1mmHg decrease in blood pressure reduces myocardial infarction (heart attack) risk by 2-3%. Treatment Progression: 1)​ Under 55 years old: Angiotensin converting enzyme (ACE) inhibitor or low cost Angiotensin II receptor blocker (ARB) ​ 55+ years old or Black: 2 calcium channel blockers 2)​ Use ACE or ARB with 2 CCBs 3)​ ACE/ARB + CCB + Thiazide like diuretic​ ​ If the patient doesn’t respond to this, they are classed as resistive hypertensives 4)​ ACE/ARB + CCB + Diuretics + More diuretics or an alpha/beta blocker. Will also require expert advice Smoking Risk is linked to the effect on vasculature; the effect is dose dependent. If you smoke more, the risk is higher. Overall, relative risk of IHD in smokers is three times greater than age matched counterparts. By stopping smoking, the risk begins to fall and so, the earlier you stop, the longer your life expectancy. Generally people develop either a physiological or psychological nicotine addiction. Physiological dependence is indicated by how soon after waking up someone has to smoke. Treat addiction with nicotine replacements and antidepressants. Future challenges involve looking into the effects of E-cigarettes and lower quality air. Type 2 Diabetes Insulin resistance leads to hyperglycemia. Risk of IHD is 2-3 times higher, slightly greater in women HbA1c is glycated haemoglobin (Hb bound to glucose) and it’s levels are an indicator of insulin resistance. Every 1% reduction in HbA1c leads to: 14% decrease in MI risk, a 37% decrease in microvascular complication, a 21% decrease in diabetes related death and a 21% decrease in risk of reaching endpoint disease related to diabetes. All T2DM complications (except cataracts) are associated with systolic blood pressure and thus, decreasing systolic pressure by 10mmHg leads to: 11% decrease in MI risk, a 13% decrease in microvascular complication, a 15% decrease in diabetes related death and a 12% decrease in risk of diabetes other complications. In short, glucose has two shared sources of risk increases; decreasing blood pressure and blood sugar both decrease the risk of MI. Metabolic Syndrome This is a cocktail of many risk factors in one person Obesity (waist circumference 94cm in men, 80cm in women) + two of these factors: Raised TAG levels- ≥ 1.7mmol/L (150mh/dL) Reduced HDL- Males: