Cardiac Catheterization Trumps CT Scan For Detecting Heart Blockage

Kathleen Blanchard's picture
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CT scans are less invasive and carry less risk for patients who have symptoms of heart blockage. The test, though fairly accurate, are still not considered as diagnostic as cardiac catheterization, otherwise known as coronary angiography.

Cardiac catheterization carries risks of bleeding, stroke from clot mobilization and heart attack. A guide wire is used to insert a catheter through the patient's groin and into the heart, following sedation and a local anesthetic in the groin area. Dye is then injected through the catheter to allow imaging cameras to follow the blood flow to the heart to detect heart blockages. High resolution CT scans can detect blockages, but they expose patients to high doses of radiation, and miss about 13% of blockages according to a study analysis.

According toresearchers at Johns Hopkins, cardiac catheterization is still the best choice of testing for anyone suspected of heart blockage. Julie M. Miller, MD; one of the hospital researchers says, "CT angiography cannot replace conventional coronary angiography in this population of patients at present,"

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Many patients cannot undergo stress testing, currently recommended as a screening tool for heart blockages. .CT scans can provide "an alternative diagnostic tool," according to the Hopkins researchers, and could be used to "rule in or rule out" heart blockages.

Alternative stress tests include the administration of drugs as Doutamine, which stimulates the heart. An Adenosine stress test can also be given. Adenosine increases blood flow the heart, as occurs with exercise, while patients sit for the test. Stress testing without exercise is given in conjunction with nuclear imaging scans that also trace blood flow to the heart, known.

In an editorial to the John's Hopkins findings, Rita F. Redberg, MD, director of women's cardiovascular services, and Judith Walsh, MD, MPH, of the University of California, San Francisco suggest more studies are need to define the role of CT technology in screening for heart blockages. They write, "Without such evidence, a high-resolution cardiac CT angiographic image of the heart is just another pretty picture."

CT scans cost less, and appeal to many patients because they are less invasive. If CT scan (or stress testing) detects heart blockages, cardiac catheterization is still needed to perform procedures, such as stent placement or angioplasty. The dual treatment could actually increase patient cost.

The study appears in the Nov. 27 issue of the New England Journal of Medicine.

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