October 5, 2010 in Nation/World

Gene test for heart disease aimed at reducing angiograms

Marilynn Marchione Associated Press
 

It’s not a perfect test. Yet researchers report a key step for the first gene test aimed at reducing unnecessary angiograms – expensive and somewhat risky procedures that hundreds of thousands of Americans have each year to check for clogged arteries. Most of these exams, done in hospital cardiac catheterization labs, turn out negative.

A simple blood test to show who truly needs an angiogram would help, and 6,000 people have had the gene test since it went on sale last year. It has drawbacks. It suggests too many chronic chest pain sufferers have heart disease when they really don’t, and misses others who do.

Today, an American Heart Association journal will publish details of an international effort by scientists to pool information and find more of these genes.

“This could ultimately really help to reduce unnecessary angiograms,” Dr. Eric Topol, of Scripps Health in La Jolla, Calif., said of the test.

He led the study of the test, called Corus CAD. The research was published Monday in Annals of Internal Medicine.

Chest pain is never a symptom to ignore; it can be a sign of a blocked artery causing a heart attack. But millions of people have chronic chest pain that might mean arteries starting to clog or another problem, even just anxiety.

The new test is for these non-emergency cases. It costs $1,195. Results take three days.

Unlike other gene tests that try to predict the odds of someday developing heart disease, this one aims to tell whether you have it now. Rather than looking for certain genes or mutations, it measures how active 23 key genes are.

Scientists developed the test from gene information on 226 patients, analyzed it in 640 patients, and on Monday reported a validation study of it in 526 others.

All had symptoms warranting an angiogram, in which a tube is placed in a blood vessel in the groin and dye is injected to make clogs in heart arteries show up on X-rays. It’s the gold standard for diagnosing heart disease, but it costs more than $30,000 and involves a large amount of radiation.

To decide whether to order one, doctors use formulas that consider a patient’s age, gender and type of chest pain. The gene test was compared to these methods. It improved diagnosis for 16 percent more patients than the leading method, as verified by angiograms they had later.

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