In many patients, the first symptom of coronary artery disease is heart attack or sudden death, with no preceding chest pain as a warning. Screening tests are of particular importance for patients with risk factors for coronary heart disease. The gold standard for coronary artery disease is coronary angiogram, used to identify the exact location of disease, anatomical details and the severity of disease.

 

Importance of health screening in heart disease

Major heart attack could be the first and only symptom of coronary artery disease, at least in the beginning.

Since it is very difficult to wait for the onset of signs and symptoms that pre-empt a heart attack, and then diagnose a heart problem, it’s always good to have a health check-up, even if you feel you are perfectly healthy.

Screening for heart disease in normal individuals is done by 35 yrs. If the risk factors for heart disease is there then it to be done by 30 yrs.

But otherwise, the person should have a check up by the age of 35 years and repeat it once every 5 years until the age of 50, and once every two years thereafter, and once every year after the age of 55.

The prime purpose of screening for heart disease is to diagnose patients having heart disease at an early stage, and treat the condition well in advance.

The importance of screening for heart disease as a preventive measure cannot be stressed enough. It can end up saving the life of the individual.

Risk factor assessment and screening

• Family history – update regularly, screening at the age of 30 yrs 
• Smoking status – ideal is to quit smoking 
• Level of alcohol intake – at every routine evaluation
• Diet – rich in proteins and vitamins, reduced fat and carbohydrates  
• Blood pressure – at each visit, at least every 2 years
• Fasting blood glucose – at least every 5 years, every 2 years if risk factors are present (diabetes is a risk factor for heart disease) 
• Body mass index – at each visit, at least every 2 years 
• Waist circumference – at each visit, at least every 2 years  
• Fasting serum lipoprotein or total and HDL cholesterol – at least every 5 years, every 2 years if risk factors are present 
• Level of physical activity – end sedentary life styles

Initial screening test for heart disease

Initial screening test for heart disease involves stressing the heart under controlled conditions.

There are two types of stress tests; those that involve exercising the patient to stress the heart (exercise cardiac stress tests), and those that involve chemically stimulating the heart directly to mimic the stress of exercise (physiologic stress testing).

Exercise cardiac stress test - ECST

• In a patient at high risk for CAD (e.g.: older age, diabetes, hypertension), an abnormal ECST is very predictive of the presence of CAD (over 90% accurate).
• A relatively normal ECST may not reflect the absence of significant disease in a patient with the same risk factors.
• Conversely, in a low- risk patient, a normal ECST is very predictive of the absence of significant CAD (over 90% accurate), but an abnormal test may not reflect the true presence of CAD (so-called "false-positive ECST").

Radionucleide stress test

• Radionucleide stress testing involves injecting a radioactive isotope (typically thallium or cardiolyte) into the patient's vein after which an image of the heart is taken.
• During exercise, if a blockage in a coronary artery results in diminished blood flow to a part of the cardiac muscle, this region will appear as a relative "cold spot" on the radionucleide scan.
• Radionucleide stress testing, while more time consuming and expensive than a simple ECST, greatly enhances the accuracy in diagnosing coronary artery disease.

Stress Echocardiography

In a heart with normal blood supply, all segments of the left ventricle exhibit enhanced contractions of the heart muscle during peak exercise.

Conversely, in the setting of coronary heart disease, if the part of the left ventricle does not receive blood flow during exercise, that part will demonstrate reduced contractions of heart muscle relative to the rest of the heart on the exercise echocardiogram.

Patients who are unable to exercise adequately- Pharmacological stress test

Dobutamine is slowly administered to gradually increase the heart rate and strength of the contractions of the heart muscle.

Simultaneously, echocardiography or radionucleide imaging is performed.

Alternatively, a medicine called adenosine is administered; adenosine is combined with radionucleide isotope imaging to provide a very accurate test for the detection of significant coronary artery disease.

Non invasive test in heart disease

• Ultrafast CT is designed to measure calcium deposits in the coronary arteries.
• In patients with coronary artery disease, the plaques which make up the blockages contain significant amounts of calcium, which can be detected with Ultrafast CT.
• The major value of Ultrafast CT is in the screening of young patients with one or more risk factors for the development of heart disease.
• Ultrafast CT scanning is of limited value in older patients, in whom some degree of calcification is commonly found.

Most accurate method for defining coronary heart disease

Coronary Angiography

The coronary angiogram is the only test which allows the precise examination of the extent and severity of coronary artery disease to optimally make these treatment decisions.