Knowing your risk for a Heart Attack -What’s in the numbers?

Heart attack concept. Senior man suffering from chest pain indoor

Heart disease is the leading global cause of death. Every year, over 17 million people die of heart disease, and this number is expected to reach 24 million by 2030. Ironically, heart attack often affects people at the height of their professional careers with profound social, economic and vocational consequences. Although recent pharmaceutical and technological advances have improved the outcome of patients hospitalised with a heart attack, the suddenness with which heart attack develops and takes its victim by surprise poses a significant barrier for any timely medical intervention. Almost half of deaths from heart attack happen outside a hospital within one hour, before the person can reach the hospital or before the hospital can reach him/her. Many of these victims of heart attack were normally functioning apparently healthy people without any symptoms of an impending health catastrophe. Hence, it is evident that prevention of heart attack in the non-suspecting people cannot be overemphasised.

Epidemiological researchers have identified several biological and social factors that increase the risk of heart attack. Fortunately, most of these ‘traditional risk factors’ are modifiable by specific preventive measures. For example, a substantial decline in heart attack rates in the communities can be achieved through the universal adoption of healthy lifestyle practices, such as regular physical exercise, smoking cessation, and healthy diet. Appropriate management of health conditions like hypertension, high blood cholesterol and diabetes has also been found to reduce the risk of heart attack. In addition to these general measures, specific preventive therapies are now available that could significantly reduce the risk of heart attack in individual patients.

A major challenge facing the contemporary healthcare practitioners and medical scientists lies in identifying individuals who are at elevated risk of a heart attack and who would potentially benefit from the available preventive therapies cost-effectively. The task is especially difficult among apparently healthy people who are free of any symptoms and yet could be at high risk of heart attack. While a general estimate of the ‘relative risk’ for heart attack can be approximated by counting the number of traditional risk factors present in a patient, a more precise estimation of the ‘absolute risk’ is desirable when making treatment recommendations for individual patients.

Physicians generally estimate the risk of heart attack using mathematical algorithms called ‘risk calculators.’ The first such risk calculator to be clinically used was the ‘Framingham Risk Score’ derived from the famous Framingham Heart Study. It uses a person’s current age, cholesterol level, blood pressure, smoking history and diabetic status to estimate his/her gender-specific risk of heart attack in next ten years. The original Framingham score was later found to have limitations in generalisability and accuracy. Several other risk calculators that included additional risk markers like physical inactivity, family history of heart disease, ethnicity, and social deprivation were subsequently developed. These different risk calculators provide 10-year estimates of the risk of heart attack in the form of a percent figure; some of these can even be used to assess the 30-year or lifetime risk.

Although it might seem cumbersome at the outset, most of the available risk calculators are simple and easy to use. Their application has been further simplified by the development of online tools wherein a physician just needs to plug in few values to get the risk estimate for an individual patient. Lately, applets based on risk prediction algorithms have become freely available on hand-held electronic devices for more efficient and easy use in physicians’ offices.

Estimation of the risk of heart attack helps both physicians and their patients in decision-making regarding any further clinical workup and mitigation of the actual risk of a heart attack. A patient is considered to be at high risk if his/her 10-year risk estimate is ≥ 7.5% and low risk if it is <2.5%. Individuals who are found to have high risk are advised appropriate further clinical testing and risk reduction therapy while those at low risk are encouraged to continue and optimise healthy living habits. The American College of Cardiology and the American Heart Association currently recommend to assess estimate 10-year risk every 4 to 6 years in adults over 40 years of age who are free from heart disease; assessing 30-year or lifetime risk may be considered in adults 20 to 59 years of age who are not at high short-term risk.

A limitation of the available ‘heart attack risk estimation tools’ is that these may sometimes overestimate or underestimate the actual risk of a heart attack. Further, a substantial number of individuals are categorised in the ‘intermediate risk’ category (10-year risk between 2.5% and 7.5%) where management decisions are less clear. Over the past few decades, medical researchers have identified additional risk markers knowledge of which could improve our accuracy of predicting heart attack. Scientists have also attempted to use imaging modalities like ultrasonography, computed tomography scanning, and magnetic resonance imaging to identify abnormalities that may predate a heart attack. While some of these ‘Novel Biomarkers’ appear promising, these are not ‘Prime Time’ yet for routine clinical application.

In summary, estimation of an individual’s risk of heart attack can potentially provide a window of opportunity to intervene and reduce or eliminate the risk of heart attack in apparently healthy people. Such risk estimation can be easily performed in terms of an objective number in physician’s office. No single risk model will be appropriate for all patients, and your physician will determine the most appropriate risk assessment tool for you and any need for additional testing.

So next time you walk in for a health check, ask your physician about your ‘number’ to help you take appropriate steps for preventing a heart attack!

 

Written By :

Dr. Abdul Rauoof Malik – MBBS, MD, DM
Specialist Cardiologist
PrimaCare Speciality Clinic – Bur Dubai

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