Category: Coronary heart disease

Risk assessment at individual level

In contrast to community-based public health interventions, clinicians are responsible for preventive advice for a particular patient. An important step in determining an individual preventive strategy is to assess the risk of developing a clinically significant outcome, because indicators of the cost-effectiveness ratio of any intervention vary depending on the overall risk of the individual or population.

Since the absolute risk in people with an established disease is high, in order to save one life or prevent one cardiovascular event (SSSob) among them, fewer people with high risk should be treated compared with the number of people with lower risk, even if the decrease in relative risk is the same in both groups.

To illustrate this point, suppose that intervention reduces mortality by 25% in primary and secondary prevention, then a high-risk patient with coronary heart disease (CHD) has a chance to die from cardiovascular disease (CVD) over the next 10 years equal to 20%, while in a patient with a low risk, the chance of dying for the same period is 1%.

To save one life among high-risk individuals, only 20 patients need to be treated for 10 years, and 4 of them will die. Thus, reducing the relative risk by 25% will save one life (3 death instead of 4). In the case of a low risk, so that a 25% reduction in relative risk would lead to 3 deaths instead of 4, 400 people will have to be treated, of whom 4 will also die.

Thus, the total cost of one life saved is significantly lower (1/20 of the cost) among those with a high absolute risk. Costly interventions are usually cost-effective only for high-risk individuals, but with a low intervention cost, the cost-effectiveness relationship can be cost-effective even in low-risk populations.

When forecasting a risk, the “ideal” risk factor (DF) is one whose prevalence prevails in a population that can be easily and safely measured and which has a great predictive value.

The measurement should be inexpensive because cost is a major constraint on the use of imaging techniques such as electron beam tomography (CRT) or MRI. In addition, the frequency of false positives should be low to avoid unnecessary and potentially dangerous consequences. Age and gender are examples of non-modifiable risk factors (RF) that meet these criteria.

Blood pressure and smoking are examples of modifiable risk factors (RF) that are easy to identify. The results of diagnostic tests can also serve as predictors of future cardiovascular events (SSSob).

Risk factor assessment at the population level

To conduct sound public policy, it is necessary to assess the contribution of various risk factors (RF) at the population level. The population risk depends not only on the strength of the factor-disease association and the benefits of the intervention, but also on how widespread this risk factor (RF) is in the population.

For evaluation, indicators such as the frequency of new cases, prevalence, and population attributive risk are used. The frequency of new cases is the emergence of new cases of disease or risk factors (RF) for a certain period of time; prevalence is the proportion of people with a specific disease or risk factor (RF) at a given time.

The population attributive risk shows what amount of risk is caused by a given risk factor (RF), and depends on the proportion of people with this risk factor and on the magnitude of the associated risk.

Population attributive risk also reflects the relationship between exposure to a risk factor (RF) and a disease. Many factors linearly increase risk, so a population attributable risk can be calculated relative to the ideal standard or to an individual with a low risk.

For example, the relationship between hypertension and heart disease or cerebral stroke (MI) is linear, so a decrease in blood pressure at any elevated level reduces the risk. In contrast, the shape of the risk curve for obesity is not linear, the risk increases logarithmically, i.e. Each kilogram gained is associated with a higher risk for those who are already overweight.

Population attributive risk is an important criterion in determining the resources needed for carrying out various preventive interventions and determining priorities in measures to improve public health, such as anti-smoking campaigns. However, this chapter focuses on individual risk assessment for predicting future cardiovascular events (SSSob).

The use of risk factors in clinical practice

Regardless of how risk factors (RF) affect the progression of atherosclerosis, they can be divided into 2 broad categories depending on their use in clinical practice:

(1) factors that are useful for risk prediction (risk predictors);
(2) factors that are targets for risk reduction interventions.

Such risk factors (RF), such as smoking and blood pressure, fall into both categories. Even if a particular factor has predictive value, it cannot be argued that modifying it will reduce the risk. If the benefit of an intervention is substantially greater than any of its risks and costs, then the intervention should be used in the appropriate population. So, how do you decide which risk factor (DF) to use as a predictor of risk and what will be the target for risk reduction?

The approaches to using a risk factor (RF) for predicting or reducing risk will be defined below. This article discusses only those risk factors (RF) that affect intermediate or long-term risk. Interventions used to quickly reduce short-term risk, such as aspirin or thrombolysis in acute myocardial infarction (AMI).

Forecasting and risk assessment. Risk prediction can be applied both to the population as a whole and to the individual. Information about the population can be obtained by studying a representative population sample in order to establish the frequency of various risk factors (RF) and plan public health objectives and resources for screening programs.

Individual risk assessment is carried out in order to identify in the population of a separate part of individuals who need a more intensive risk reduction program.

The articles on the site will briefly describe the assessment of the risk factor (RF) and the frequency of events in the general population, and further – a detailed assessment of the individual risk.

Cholesterol recommendations and control

All patients with cardiovascular diseases (CVD) should be screened to determine the level of cholesterol in serum. Some controversy remains regarding screening for primary prevention. The NCEP recommends routine screening for all individuals> 20 years old, ACP (American College of Physicians) – only men 35–65 years old and women 45–65 years old, and USPSTF – screening all men aged> 35 years old and women aged 45 years old. Screening for CVD patients should include a complete fasting lipid profile, including total cholesterol, cholesterol, and HD. For patients without CVDs, the need for screening for HDL cholesterol is questionable: the NCEP recommends such screening, but the ACP does not.

Due to the fact that cholesterol cholesterol levels and the ratio of cholesterol to cholesterol cholesterol are very strong predictors of risk and help in identifying individuals with elevated levels of LDL cholesterol, despite moderate levels of cholesterol, it seems appropriate to determine cholesterol cholesterol simultaneously with cholesterol. .

To reduce the prevalence of HLP in the United States, the NCEP in 1988 released the first report on the treatment of HCS in adults. The latter was published in 2002, in 2004 some components were updated. According to the latest NCEP guidelines, the number of adults in the United States who need to modify lipid levels through lifestyle changes has grown from 52 million to 65 million, and those who need medication from 13 million to 36 million. The goals of the intervention are determined based on the individual risk of coronary heart disease. (KBS).

The updated ATP III guideline recommends different therapeutic goals depending on the patient’s overall risk calculated on the Framingham scale, taking into account other risk markers (elevated levels of TG, CRP and family history). Patients with an existing ASC (or its equivalent – DM or PAD) are at the highest risk of a cardiovascular event (SSSob), therefore their target level of ANS cholesterol is the lowest – <100 mg / dL or even lower – <70 mg / dl for those who have recently had ACS or have KBS and diabetes or high or poorly controlled RF.

In 2006, the ACC / ANA updated their secondary prevention guidelines on lipid control, repeating the recommendations made by the NCEP and strengthening some of them. As with the NCEP guideline, a target LDL-C level of <70 mg / dL was added as optional. However, ACC / ANA expanded the choice of target LDL cholesterol levels <70 mg / dl for all patients with CHD, and not just those who have a very high risk; However, this position is not supported by all researchers. In addition, patients with a TG level of 200-499 mg / dL should have a non-HDL cholesterol content <130 mg / dL, and further decrease to <100 mg / dL is considered appropriate.

According to the NCEP primary prevention guidelines, patients with a moderately high risk of CHD (RF> 2, total 10-year risk 10-20%) should receive appropriate therapy to achieve LDL <130 mg / dL (optimally <100 mg / dL) . These indicators are also a goal for patients with moderate risk (RF> 2, 10-year risk <10%). For patients with a lower risk, the target LDL level should be <160 mg / dL. In addition to this, according to the recommendations of the NCEP on lifestyle changes, the diet should include 25-35% of calories due to fat, while the proportion of saturated fatty acids should be <7% and cholesterol <200 mg / day.

It is difficult for patients to understand the calculation of calories in percentages, so it is recommended to convert them to grams of fat, protein and other components of the diet. Professional nutrition counseling can also be helpful. If using dietary therapy fails to reach the target level of LDL cholesterol, it is necessary to begin drug therapy. In all cases, it should be an addition to diet therapy and increase of FA.

The guidelines of the European Society Cardiology also include gradations of target levels. Although they are identical for all patients (cholesterol <190 mg / dl, or 5 mmol / l; LDL cholesterol <115 mg / dl, or 3 mmol / l), the duration and intensity of drug therapy are different. In primary prevention, if the 10-year absolute risk of CHD or a risk calculated for the age of 60 years> 5%, modification of the lifestyle and analysis of lipid levels after 3 months are recommended. If after this time, cholesterol or LDL cholesterol is still above the target level, then you can begin drug therapy.

For asymptomatic high-risk patients who have cholesterol and LDL cholesterol are close to target levels (5 and 3 mmol / l, respectively), target levels should be <4.5 mmol / l (175 mg / dl) for cholesterol and <2, 5 mmol / l (100 mg / dl) for LDL cholesterol. The same target levels are set for persons with KBS and / or SD.

In secondary prophylaxis in patients with high LDL cholesterol and low HDL cholesterol or high TG, aggressive treatment is necessary, perhaps even combined. For individuals with established disease, low levels of HDL cholesterol and normal LDL cholesterol, pharmacological intervention may be considered based on the results of the VA-HIT study.

Efficacy of taking ACE inhibitors and direct anticoagulants for coronary heart disease

Efficacy of an ACE inhibitor (ACE inhibitor) in coronary heart disease (CHD). There is ample evidence of the benefits of an ACE inhibitor in individuals with a high risk of coronary heart disease (CHD). After myocardial infarction (MI), an ACE inhibitor is associated with a 7% decrease in mortality by day 30 of the disease. Among patients with myocardial infarction with low EF, the decrease in total mortality is 26%.

A meta-analysis of 6 randomized controlled trials showed that long-term therapy with an ACE inhibitor reduces the risk of major clinical outcomes by 22%. The NORE study revealed that the benefits of an ACE inhibitor apply to patients with CHD and DM, even in the absence of LV dysfunction. The results of the CHARM (Candesartan in Heart Failure Assessment of Mortality and Morbidity) study showed that the use of ARBs of candesartan in patients with HF can prevent 1 death in the treatment of 63 patients, 1 first hospitalization for HF in the treatment of 23 patients and 1 new case of diabetes in the treatment of 71 patients.

Efficacy of direct anticoagulants for coronary heart disease (CHD). Per os anticoagulants prevent embolic complications in patients with prosthetic heart valves and atrial fibrillation. The role of the anticoagulant as an independent drug or in combination with aspirin in the secondary prevention of patients with coronary heart disease (CHD) is less defined.

The results of randomized controlled trials are ambiguous, anxious is such a side effect (PE) of anticoagulants as bleeding.

The 1999 meta-analysis provided comprehensive data on the different efficacy of treating patients with cardiovascular disease (CVD) with anticoagulants of varying intensity in combination with aspirin or aspirin alone as compared with placebo. In this analysis, it was shown that treatment with moderate or high intensity anticoagulants reduced the incidence of MI and MI compared to placebo, but increased the risk of hemorrhage.

The combination of low-intensity anticoagulants with aspirin did not lead to an increase in efficacy compared with aspirin alone, while a combination treatment with moderate-to-high-intensity anticoagulants with aspirin gave promising results. However, a recent analysis included the results of more recent studies of CHAMP (Cardiac Hospitalization Atherosclerosis Management Program), LoWASA (Low-dose warfarin and aspirin), WARIS II (Warfarin-Aspirin Reinfarction Study) and ASPECT-2 (Antithrombotics in the Secondary Prevention of Events in Coronary Thrombosis) led to the conclusion that moderate to high intensity anticoagulants should not be used routinely as an alternative or aspirin supplement in patients with acute coronary syndrome (ACS) because of the increased risk of bleeding.

Additional clinical studies are needed comparing the effectiveness of a combination of anticoagulants with clopidogrel. c) Recommendations. Aspirin should be used to treat all patients with various forms of coronary artery disease. The combination of aspirin with another anti-platelet drug, such as clopidogrel, should be used only in acute situations when treating patients at very high risk.

β-AB should be considered for the treatment of patients after MI or with HF. An ACE inhibitor should be considered a standard cost-effective therapy for patients with low EF and other high-risk patients. All three classes of the drug are recommended by AHA, ACC and ESC for secondary prophylaxis. The USPSTF recommended aspirin for primary prophylaxis in patients with a 5-year risk of CVDs> 3% (equivalent to 6% of a 10-year risk).

Per os anticoagulants, although they are clearly useful in the treatment of patients with AF and certain prosthetic heart valves, are not recommended for the general prevention of KBS-related events.

The effectiveness of physical training for coronary heart disease

The prevalence of low physical activity (NFA). NFA is one of the most frequently occurring modifiable RFs. National Health Interview Survey data showed that 70% of American adults do not follow current guidelines for 30-minute mild or moderate physical activity (FA) for at least 5 days a week or intense physical activity (FA) for at least 20 minutes 5 days a week.

About 25% do not engage in any physical activity (FA) in their free time, while women lead a more sedentary lifestyle compared to men. The lack of sufficient FA is also common in children. Only a small number of schoolchildren have daily physical education classes, and children have had less time spent walking and cycling. On the contrary, the time spent on such sedentary activities, such as watching TV, computer games, has increased dramatically. It is unlikely that older people, most of whom are at risk for CVD, will be more physically active than the young.

All of these demographic changes have led to an increase in the incidence of diabetes among children, so diabetes mellitus-2 is no longer considered an adult disease.

Associated with low physical activity (NPA) risk. Results> 40 observational studies revealed a clear inverse linear dose-dependent relationship between FA and OS of men and women of younger and older. The results obtained in the mid-1950s showed that the frequency of KBS was lower for bus and postman conductors compared with slow-moving bus drivers and postal managers. Having included the evaluation of FA in their free time from work, the researchers found that employees who were engaged in intensive sports had MI 2 times less often than employees who were not involved in these activities. Later, in a number of observational studies, the same inverse relationship was found between the degree of FA at work or sports and KBS.

Minimal adherence to modern recommendations on physical activity (FA), which is accompanied by costs of 1000 kcal / week, is associated with a significant reduction in the risk of OS by 20-30%. A 1990 meta-analysis of 27 observational cohort studies revealed that the risk of KBS among people with a sedentary lifestyle after control of other RFs is almost 2 times higher than that of physically active people. Long-term, prospective studies of men and women have shown that FA protects against legal outcome in CHD.

For this, a simple fast walk is sufficient, which, as has been shown, reduces the risk of CHD in women and men, as well as the risk of diabetes mellitus 2. Even in a later period of life, the transition from a sedentary lifestyle to a more active one leads to a decrease in mortality from KBS. FA is also associated with a reduced risk of MI in men and women, primarily due to its beneficial effect on serum MT, BP, serum glucose tolerance and glucose tolerance.

Although there are no large-scale randomized studies of physical activity (FA), a number of studies have been conducted of moderate size and duration among healthy individuals and CVD patients. Despite differences in design, these studies have generally demonstrated the benefit of FA. However, the FA of ideal intensity, frequency, and duration has not yet been determined.

Benefits of Weight Loss and Obesity Treatment

There are no large-scale randomized studies of isolated weight loss (MT) interventions to evaluate the effect of this reduction on reducing the risk of CHD. However, there is enough information from a number of observational studies and small randomized clinical trials for the duration to conclude that a decrease in MT brings significant health benefits. A small (by 5-10%) decrease in MT is associated with a significant improvement in blood pressure in individuals with and without AH. A small decrease in MT improves the lipid profile, reducing the level of TG, increasing the level of HDL cholesterol and slightly reducing cholesterol and LDL cholesterol, as well as increasing glucose tolerance and / or TS. Reducing MT also helps relieve sleep apnea.

However, there is no consistent approach to reducing MT, and the results of lifestyle modifications to reduce MT are disappointing. In the USA, 25% of men and 43% of women try to reduce MT during the year, but the rate of failed attempts is very high. One of the reasons may be that most people trying to reduce MT do not follow recommendations to reduce calorie intake and increase physical activity (FA) to at least 150 minutes a week.

Effective treatment strategies are usually multifaceted, including nutritional counseling, behavioral therapy, increasing FA and psychosocial support. Recent observational and clinical studies have shown that pharmacotherapy and bariatric surgery may be helpful in reducing MT, but long-term success and risk, as well as the cost-effectiveness relationship, have not been fully evaluated.

The ratio of cost-effectiveness. The lack of benefit assessments and the large variability of intervention strategies do not allow an assessment of the cost-effectiveness ratio of programs or interventions to reduce MT.

Recommendations and guidelines. The guidelines developed by the National Heart, the Lung and Blood Institute and the North American Association for the Study of Obesity offer a threefold strategy for reducing MT, which includes calorie restriction, structured physical activity (FA) and behavioral therapy for all patients with an IMT of> 30 kg / m2, for patients with BMI = 25.0-29.9 kg / m2, suffering from CHD or having RF> 2 (see further discussion of interventions using specific FN and nutritional recommendations). For some patients, pharmacotherapy is suitable, and for very obese patients – bariatric surgery.