Using a Gene Test to Better Identify Heart Disease in Patients With Chest Pain

Investigators. What is the problem and what is known about it so far? When patients have chest pain, their physicians can have difficulty deciding whether it is a sign of disease in the blood vessels around the heart, called coronary artery disease (CAD). To evaluate the risk for CAD, physicians can use information gained from studies of large groups of patients, knowing that older persons, men, smokers, and diabetic persons have a higher risk for CAD. Physicians can also obtain heart tracings (electrocardiograms) or stress tests that can indicate signs of damage or a problem with the heart’s blood supply. However, many patients still go through a costly and somewhat risky test called coronary angiography (in which a catheter is placed through a blood vessel in the arm or groin to examine blood vessels around the heart with dye) but are found not to have CAD, whereas others are found to have CAD despite few signs or risk factors. Therefore, better approaches are needed to identify patients with chest pain who are more likely to have CAD. Analysis of a patient’s genes may be a useful tool to help distinguish patients with CAD.


What is the problem and what is known about it so far?
When patients have chest pain, their physicians can have difficulty deciding whether it is a sign of disease in the blood vessels around the heart, called coronary artery disease (CAD). To evaluate the risk for CAD, physicians can use information gained from studies of large groups of patients, knowing that older persons, men, smokers, and diabetic persons have a higher risk for CAD. Physicians can also obtain heart tracings (electrocardiograms) or stress tests that can indicate signs of damage or a problem with the heart's blood supply. However, many patients still go through a costly and somewhat risky test called coronary angiography (in which a catheter is placed through a blood vessel in the arm or groin to examine blood vessels around the heart with dye) but are found not to have CAD, whereas others are found to have CAD despite few signs or risk factors. Therefore, better approaches are needed to identify patients with chest pain who are more likely to have CAD. Analysis of a patient's genes may be a useful tool to help distinguish patients with CAD.

Why did the researchers do this particular study?
To investigate how well their previously developed gene test, with a score based on the pattern of 23 genes that may be associated with having CAD, performed in patients who had chest pain.
Who was studied? 526 nondiabetic patients with chest pain or another indication for coronary angiography.

How was the study done?
The patients had their gene test score determined from a blood sample and then underwent coronary angiography to evaluate whether they had significant disease, defined as narrowing of at least 1 heart blood vessel by 50% or more. The authors then compared the effectiveness of the gene test score in identifying patients who did or did not have CAD with that of 3 other CAD risk measures.

What did the researchers find?
The gene test modestly improved physicians' ability to find patients with CAD compared with a measure that looks at the type of chest pain and some patient characteristics. Compared with using more clinical information available to the physician, the improvement from using the gene test was small. The test was better able to identify patients who had the disorder than those who did not.

What were the limitations of the study?
The study patients were referred for evaluation of chest pain, so they had an increased risk for heart disease. The gene test could not be performed on patients with certain types of diseases, such as diabetes or rheumatoid arthritis, and is expensive.

What are the implications of the study?
These results suggest that further work is needed to examine how a gene test score can complement other ways of distinguishing patients who have clinically important CAD from those who do not.

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