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Prevention of Cardiovascular
Diseases in Latin America
Edgardo Escobar, MD
Departamento de Medicina, Hospital San
Borja, Universidad de Chile,
In the last few decades, the causes of cardiovascular disease have changed, being before, rheumatic heart disease the most frequent one.
Nowadays, valvular heart disease of this cause has had a significant decrease, due to the improvement of socioeconomic conditions and the correct treatment of streptococcal infection.
In some Latin American countries still exists a high rate of chagasic cardiomyopathy which has shown a slow but progressive decrement thanks to public health campaigns.
On the other hand, hypertension, obesity, and diabetes have become more relevant. Each one of them represents an important cause of cardiovascular disease. Due to them and other causes like tobacco abuse and lack of physical activity atherosclerotic disease is the epidemy of the XXI century.
In 1999, 50 million people died and in 6.3 million the cause was coronary heart disease (CHD). Interestingly, only 2.7 million were from developed countries. More than 4 million died due to a cerebral vascular accident (CVA) and only 1.4 million were from first world's countries.
For the year 2020 it is expected that 7 out of 10 deaths would be by no transmissible disease, CHD being the main reason and CVA ranking in the fourth place.
In Latin America and the Caribbean there are twice more deaths due to non transmissible diseases than transmissible diseases.
Risk factors of the atherosclerosis disease are well known. It is important to remember that those factors potentiate each other. For example, if tobacco abuse, hypertension and dyslipidemia coexist the risk can increase sixteen times.
Mortality rate due to disease of cardiovascular system, according to the OPS, are quite high in Latin America and they have not changed significantly between 1980 and 1990. Some examples:
Argentina: 46.6 and 46.4, Chile: 29.4 and 29, Honduras: 15 and 13.9, Puerto Rico: 50 and 34, Uruguay 44.1 and 41.4 %, respectively.
Latin America has dealt and keep dealing with high rates of migration which influenced their genetic characteristics and living and nutritional habits.
A recent publication of the Interamerican Heart Foundation reports detailed statistics of cardiovascular diseases in America. This information shows the high rate of mortality due to atherosclerotic disease in Latin American countries.
The prevention of cardiovascular diseases must be based primarily on a change of lifestyles and, in a second place, on the use of pharmacological tools.
Studies performed in Chile and Argentina show that urban and rural population have a similar prevalence of cardiovascular risk factors. Therefore, prevention is a synonymous of EDUCATION of general population, process that in my opinion must begin at primary school level to teach the children healthy living habits.
Important component of these habits is regular exercise, the practice of which has proved to prolong life. Regular physical activity increases the concentration of HDL cholesterol, the activity of the lipoproteic lipase of fat and muscle tissues, insulin sensibility and fibrinolytic activity secondary to thrombotic occlusion. On the other hand, it decreases the LDC cholesterol, VLDC and triglycerides concentration, heart rate and it contributes to normalize arterial pressure in mild hypertensives.
A thirty minutes daily walk is associated to a longer life. There are no studies of the impact of physical training in primary prevention but it improves quality of life.
The cessation of tobacco abuse increases the level of HDL cholesterol in the first month. In the first two months it is evident a decrease of fibrinogen levels, an improvement of the platelet function and a tendency to normalize the hypercoagulable states. In the course of the first six months, hypertensive patients under treatment with betablockers obtain total benefit in comparison with the non smokers. The risk of myocardial infarction in an ex smoker falls to the risk of a non smoker. Within five years, patients that have had angina, myocardial infarction or arrhythmia, reduce the risk of infarction or re infarction and the symptoms of intermittent claudication may decrease, in part due to collateral circulation in obstructed areas of peripheral arteries. All the above without considering the beneficial effects that produces to stop smoking on the physiology of the airways and in the decline of cancer risk, mainly pulmonary. It is projected that for the year 2020 tobacco abuse will kill more people than any other individual disease. Even passive tobacco exposure increases significantly cardiovascular risk.
Programs to stop smoking do not have an important success and they vary between 5 and 40%. This last number can be reached with multidisciplinary programs, with charges between 790 and 1200 dollars per person who stops smoking.
The primary and secondary prevention studies show above any possible doubt that reduction of cholesterol concentrations it is associated to a less incidence of cardiovascular events and mortality.
Meta analysis have shown a significant correlation between the magnitude of reduction of cholesterol concentration and less mortality. Reductions greater than 25% are associated to a prolonged survival.
The use of statins in primary prevention has a cost of 1.2 million dollars to save one life and 210 000 dollars to prolong a year of life. These are excessive costs for most of Latin-American countries. In secondary prevention the cost/benefit of using statins is considerably less and it falls to figures of 4 000 to 30,000 dollars per year of life saved. If we add the indirect costs of diseases by loss of productivity there would be an important save of resources with the use of statins.
In the majority of Latin American countries there is no access to these medications, but there is no doubt that health authorities have to do the effort to include these drugs in the treatment, including primary prevention, if we are consequent with the practice of evidence based medicine.
Regarding to arterial hypertension several studies have proven the impact of treatment on mortality. A decrease of 5 to 6 mmHg of diastolic pressure, it is associated to a 35% decrease in CVA and to a 25% decrease of acute myocardial infarction. Present information do not support the hypothesis that the use of betablockers and/or diuretics has an unfavorably influence on the prognostic of CHD and together with the other anti hypertensives should be in the first line of treatment.
Obesity is associated to a higher mortality, particularly the one characterized by an increased waist/hip ratio which is related to a higher resistance to insulin and arterial hypertension.
Obesity is an epidemiological problem of a great magnitude an importance and must be controlled since childhood. However, treatments have a high index of desertion and obtain small looses of weight.
More recently, the hyperhomocisteinemia has been included as a risk factor, but there are not long term studies that show a beneficial effect of its treatment on cardiovascular events or mortality.
Anyway, the administration of folic acid to reduce the concentration of homocysteina is very effective, and being of a low cost it is probable that in the future will be incorporated in foods, when there will be solid information of its impact in atherosclerotic disease.
Diet, independent of its effects on lipids, is important to decrease the risk of atherosclerosis. The restriction of the consumption of hydrogenated fatty acids and saturated fat it is associated to important reductions in cardiovascular risk.. The trans fatty acids are generated during the industrial hydrogenation of oils, process which is utilized for margarine production. The configuration of these acids produces changes in the function of membranes and increase the HDL and total cholesterol concentration.
Omega-3 fatty acids are highly unsaturated and exist mainly in cold water fishes. These acids reduce the platelet aggregation and decrease the concentration of triglycerides. More than replacing the diet with those fatty acids, is important to stimulate the intake of fish at least once a week which is associated to a reduction of cardiovascular mortality.
The prevalence of atherosclerotic disease risk factors in Chilean and Argentinean population, for example is similar to the one in developed countries.
Therefore, control measures of those factors should reduce morbi mortality by atherosclerosis and should be implemented promptly.
The Euroaspire II study shows very similar results to Euroaspire I, made five years before. The Euroaspire II, European study aimed to improve the prevention of cardiovascular diseases in 5556 patients hospitalized for coronary surgery, angioplasty, myocardium infarction or unstable angina, shows a high prevalence of tobacco consumption (21%), overweight or obesity (81%), sedentarism (61%), hypertension (50%), diabetes (20%), hypercholesterolemia (59%), numbers very similar to the Euroaspire I, which underlines the need of EDUCATION in relation to lifestyles, tobacco abuse, weight control and physical activity.
Programs of prevention must consider, among others factors, the need, of the population be conscious about risk factors, inculcate the concept of PREVENTION, difficult mission in apparently healthy and asymptomatic people.
This results in a high rate of desertion, between 20 and 50% of the people entering a program. Prevention programs can make necessary the incorporation of expensive medications, like statins.
The most important part is the role of health professionals and their most important tool is EDUCATION thru a good relationship with healthy people or patients.
In 1990 developed countries contributed with a 68% of the total number of deaths caused by no transmissible diseases and with 63% of the world mortality by cardiovascular diseases.
Latin America contributed in a 6% to the mortality by any cause and in a 5% to the cardiovascular mortality in 1990, and the contribution of developing countries to total global burden of cardiovascular diseases, in terms of incapacity due to years of lives lost (DALY), was 2.8 larger than countries already developed.
In summary, the prevalence of cardiovascular risk factors in developing countries and as a consequence in Latin America is similar to the one in developed countries. It is necessary to have precise measurements of the burden of cardiovascular diseases in each of the countries and to develop maximal efforts to decrease it considering the difficulty that represents the transition to a better developed economy.
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2nd Virtual Congress of Cardiology
Dr. Florencio Garófalo
Dr. Raúl Bretal
Dr. Armando Pacher
Technical Committee - CETIFAC
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