Coronary heart disease
- 1. Coronary heart disease Dr. Sanjeev Gupta Professor, Dept of Community Medicine LN Medical College Bhopal.
- 2. Introduction: • “Impairment of heart function due to inadequate blood flow to the heart compared to its needs, caused by obstructive changes in the coronary circulation to the heart“ • Cause of 25-30 per cent of deaths in most industrialized countries. • Named as modern EPIDEMICS
- 3. • Manifest itself in many presentations : • a. angina pectoris of effort • b. myocardial infarction • c. irregularities of the heart • d. cardiac failure • e. sudden death.
- 4. Measuring the burden of disease • (a) Proportional mortality ratio: CHD is held responsible for about 30 per cent of deaths in men and 25 per cent of deaths in women • (b) Loss of life expectancy : average gain in life expectation that would follow a complete elimination of all cardiovascular deaths if other mortality rates remain unchanged. The benefit would range for men from 3.4 years to 9.4 years, and even greater for women.
- 5. Contd…… • (c) CHD incidence rate: This is the sum of fatal and nonfatal attack rates • ( d) Age-specific death rates :Age-specific death rates suggest a true increase in incidence. • ( e) Prevalence rate : The prevalence of CHD can be estimated from cross-sectional surveys using ECG for evidence of infarction and history of prolonged chest pain.
- 6. (f) Case fatality rate : This is defined as the proportion of attacks that are fatal within 28 days of onset. "sudden deaths" be defined to include deaths occurring instantly or within an estimated 24 hours of the onset of acute symptoms or signs“. • 25-28 per cent of patients who suffer a heart attack die suddenly. In about 55 per cent of all cardiac deaths mortality occurs within the first hour
- 7. • (g) Measurement of risk factor levels : These include measurement of levels of cigarette smoking, blood pressure, alcohol consumption and serum cholesterol in the community. • (h) Medical care : Measurement of levels of medical care in the community are also pertinent.
- 8. Epidemicity • CHD began at different times in different countries. • Countries where the epidemic began earlier are now showing a decline. • The reasons for the changing trends in CHD are not precisely known. The WHO has completed a project known as MONICA "(multinational monitoring of trends and determinants in cardiovascular diseases)" to elucidate this issue. • Inverse relation between social class and CHD in developed countries
- 10. Coronary heart disease in India • It was expected to be the single most important cause of death by the year 2015. • There is a considerable increase in prevalence of CHD in urban areas during the last decade. • According to medical certification of cause of death data, 25.1 per cent of total deaths in urban areas are attributable to diseases of the circulatory system.
- 12. Risk factors
- 13. Smoking • The risk declines quite substantially within one year of stopping smoking and more gradually thereafter until, after 10-20 years, • Possible mechanisms carbon monoxide induced atherogenesis; nicotine stimulation of adrenergic drive raising both blood pressure and myocardial oxygen demand; lipid metabolism with fall in "protective" high- density lipoproteins, etc. • The degree of risk of developing CHD is directly related to the number of cigarettes smoked per day
- 15. Hypertension • In the past, emphasis was placed an the importance of diastolic blood pressure. • Many investigators feel that systolic blood pressure is a better predictor of CHD than is the diastolic. However, both components are significant risk factors.
- 16. To further refine CHD risk prediction based on serum lipid levels, a total "cholesterol/HDL ratio" has been developed. A ratio of less than 3.5 has been recommended as a clinical goal for CHO prevention
- 17. Other risk factors • Diabetes : The risk of CHD is 2-3 times higher in diabetics than in non-diabetics. • Genetic factors : A family history of CHD is known to increase the risk of premature death. • Physical activity : Sedentary life-style is associated with a greater risk of the development of early CHD.
- 18. • Hormones : The pronounced difference in the mortality rates for CHO between male and female • Type A personality : Type A behaviour is associated with competitive drive, restlessness, hostility and a sense of urgency or impatience. Type-A individuals are more coronary prone to CHD than the calmer, more philosophical Type B individuals
- 19. • Alcohol : High alcohol intake, defined as 75 g or more per day is an independent risk factor for CHD, hypertension and all cardiovascular diseases • Oral contraceptives: Women using oral contraceptives have higher systolic and diastolic blood pressure.
- 20. PREVENTION OF CHD a. Population strategy (i) prevention in whole populations (ii) primordial prevention in whole populations b. High risk strategy c. Secondary prevention
- 21. a. Population strategy • The strategy should therefore be based on mass approach focusing mainly on the control of underlying causes (risk factors) in whole populations, not merely in individuals. • Based on the principle that small changes in risk factor levels in total populations can achieve the biggest reduction in mortality • The aim should be to shift the whole risk-factor distribution in the direction of "biological normality"
- 22. Specific interventions 1. Dietary changes : Reduction of fat intake to 20-30 per cent of total energy intake consumption of saturated fats must be limited to less than 10 per cent of total energy intake; some of the reduction in saturated fat may be made up by mono and poly- unsaturated fats • A reduction of dietary cholesterol to below 100 mg per 1000 kcal per day • an increase in complex carbohydrate consumption {i.e., vegetables, fruits, whole grains and legumes) • avoidance of alcohol consumption; reduction of salt intake to 5 g daily or less.
- 23. 2. Smoking : As far as CHD is concerned, present evidence does not support promotion of the so-called "safer cigarette" . The goal should be to achieve a smoke-free society, and several countries are progressing towards this goal. 3. Blood pressure : It has been estimated that even a small reduction in the average blood pressure of the whole population by a mere 2 or 3 mm Hg would produce a large reduction in the incidence of cardiovascular complications 4. Physical activity : Regular physical activity should be a part of normal daily life.
- 24. PRIMORDIAL PREVENTION • It involves preventing the emergence and spread of CHO risk factors and life-styles that have not yet appeared or become endemic. • Several well-planned risk factor intervention trials (e.g., The Multiple Risk Factor Intervention Trial (MRFIT) in the US , The Stanford Heart Disease Prevention Programme in California, and The North Kerelia Project in Finland have demonstrated that primary prevention can achieve substantial reduction in the incidence of coronary heart disease.
- 25. b. High risk strategy • (i) Identifying risk : High-risk intervention can only start once those at high risk have been identified. • (ii) Specific advice : Having identified those at high risk, the next step will be to bring them under preventive care and motivate them to take positive action against all the identified risk factors,
- 26. c. Secondary prevention • Secondary prevention (SP) must be seen as a continuation of primary prevention. It forms an important part of an overall strategy. The aim of secondary prevention is to prevent the recurrence and progression of CHD. SP is a rapidly expanding field with much research in progress (e.g., drug trials, coronary surgery, use of pace makers).
- 27. Revascularization procedures for patients with angina pectoris The indications for coronary artery revascularization i.e. coronary artery bypass grafting (CABG) and percutaneous transluminal coronary angioplasty (PTCA.)
- 28. RISK FACTOR INTERVENTION TRIALS 1. Stanford-Three-Community Study: To determine whether community health education can reduce the risk of cardiovascular disease, a field experiment. • was undertaken in 1972 in three northern California towns with populations varying between 12,000 and 15,000. • In two of these towns intensive mass education campaigns were conducted against cardiovascular risk factors over a period of 2 years. • The third community served as a control.
- 29. 2. The North Kerelia Project: A county in the eastern part of Finland, where CHD is particularly common. • Its 185,000 inhabitants work mostly in farming and forestry and live in the countryside. • Two aims : (a) to reduce the high levels of risk factors for cardiovascular disease (e.g., smoking, blood pressure and serum cholesterol), and • (b) to promote the early diagnosis, treatment and rehabilitation of patients with CV disease. • A control population was established in a neighboring county which has similar CV mortality.
- 30. Other trials were: 4. Oslow diet/smoking Intervention Study 5. Lipid Research Clinics Study • Secondary prevention trials : Secondary prevention trials are aimed at preventing a subsequent coronary attack or sudden death. 3. The multiple risk factor intervention trial (MRFIT) carried . out in USA was aimed at high risk adult males aged 35-57 years.
- 31. Thank you