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Hodnotenie kardiovaskulárneho rizika

 


Traditional cardiovascular (CV) risk assessment and its limitations

Framingham and European SCORE

In asymptomatic individuals the traditional risk factors enable identification of high-risk status in two instances. The first, is when, at least one of the following major risk factors is easily determined to be present: very high blood pressure, unusually high cholesterol level, and diabetes are all synonymous with high CV risk. In the second instance, which we also call multi-factor CV risk, several milder risk factors are simultaneously present. We often are not aware of these, since the patients are asymptomatic. Those programs that integrate risk factors in a table facilitate diagnostics. The Framingham risk score is one of the most well-known, taking into account age, sex, total- and HDL cholesterol level, systolic blood pressure and smoking habits. Each risk factor carries a number of risk assessment points, which combined provide us with the so-called total risk, which expresses in terms of percentage the likelihood of the development of fatal or non-fatal coronary disease within 10 years.

The Framingham assessment is unsuitable for identifying high risk patients among those who appear healthy. The limitations stem from the geographic specificity of the method and the lack of attention given to other well-known risk factors, so in individuals with lower risk compared to the North American population, true risk values are overestimated. Thus for Great Britain, Germany, New Zealand and France, other methods are recommended.

The European Risk SCORE (Systematic Coronary Risk Score) method takes age, sex, systolic blood pressure, total cholesterol or total/HDL cholesterol ratio and smoking habits into account, and also separates results by high (northern) and low (southern) risk regions, and estimates the likelihood (in percentage) of fatal heart attack within 10 years.

Limitations of the methods

Framingham and other methods, including the European SCORE, do not take into account other well-known risk factors such as obesity (particularly abdominal), coronary events in first-degree relatives, lack of regular aerobic physical activity and psycho-social factors. Neither method takes into account metabolic syndrome, which is diagnosed by the presence of three of the following: abdominal obesity, high triglyceride level, low HDL level, high blood pressure and impaired fasting glucose level. Metabolic syndrome should be given special attention since it corresponds to high CV risk. In addition, these studies focus on fatal and non-fatal coronary events, whereas ischemic stroke is also a major cause of CV mortality and disability. The Framingham program has a stroke testing version (taking into account age, sex, systolic blood pressure, presence of anti-hypertensive therapy, diabetes, smoking habits, coronary events in clinical history, atrial fibrillation and left ventricular hypertrophy), which calculates the probability of stroke, but is not in widespread use. Besides, in the case of stroke, we are aware of specific risk factors such as ethnicity (primarily in black, Chinese and Japanese individuals), knowledge of past cardiovascular events in the family, coronary disease in clinical history, which better indicate the probability of an incidence of thromboembolic stroke. In sum, we can say that while the traditional risk factors are responsible for 90% of cardiovascular events, their predictive value is weak, because the possibility of identifying CV disease varies widely among individuals. Furthermore, 80% of CV disease cases occur in low- or medium-income countries, where the predictive value of these well-known risk factors has not been determined.

The diagnostic and predictive value of testing for subclinical vascular disease

Therefore, in numerous cases, the traditional risk factors do not serve as sufficient proof of high risk conditions, so it is advisable to improve the risk assessment of asymptomatic individuals by testing for new risk factors. Many methods exist for testing subclinical vascular damage, which focus on the examination of the structure and function of the arterial wall. (LINK az 1.3.4-re)

Individual and multifactor screening has become necessary, including for those risk factors that appear more appropriate than the traditional risk assessment elements in determination of high risk. Among the markers that have reemerged as testable, the typical parameters of subclinical arterial alterations have proven to be effective in detection of CVD.

In asymptomatic individuals who lack diagnosed cardiovascular disease, what additive value do the new, non-invasive tests targeting the small and large arteries offer in addition to the traditional risk factors?

In the past few decades, medical literature in this area and the sudden increase in data resulted in the inclusion of arterial function and the testing of large arterial wall stiffness as a compulsory element already recommended in the newest European methodological recommendations.

2007 Guidelines for the Management of Arterial Hypertension

2009 Reappraisal of European guidelines on hypertension management