When to Do a Coronary CTA: Defining Appropriate Use

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Abbott Northwestern Hospital in Minneapolis, Minn., performs 12 to 17 coronary CTAs daily with its Siemens Medical Solutions Somatom Definition dual source CT scanner.

Cardiac care is on the upswing in 2007. Aging baby boomers, advancing medical technology, more educated physicians and public awareness are driving an unprecedented growth in the diagnosis and treatment of heart disease. One of the fastest growing diagnostic procedures is the coronary computed tomography angiogram (coronary CTA) using a 64-slice CT scanner. The explosion in coronary CTA has created a need to educate cardiologists, radiologists and internists on its appropriateness of use—who, what, when, where, and why.

More and more physicians are becoming aware of the benefits of coronary CTA thanks to immense growth of 64-slice CT imaging. The benefits include speed, very low risk, and an amazing amount of information, says Tony DeFrance, MD, a board-certified interventional cardiologist and medical director of CVCTA Education Center in San Francisco. “In just 10 seconds, we can get an entire roadmap of the arteries,” DeFrance says. “We can see into the walls of the blood vessels and see the earliest stages of coronary artery disease, so we can detect it even long before an invasive angiogram.” 

The procedure offers a less-expensive, noninvasive alternative to cardiac catherization. There has been tremendous growth in the use of CTA, especially in the emergency room setting and outpatient imaging facilities. The growth is creating a huge need and demand for training in this area, says DeFrance, who each week spends most of his time teaching nearly 100 physicians onsite and across the country. But his eyes are busy reading images, too. At CVCTA, he oversees eight to 12 coronary CTAs that are performed daily on the facility’s Toshiba America Medical Systems’ Aquilion 64. 

DeFrance’s outreach is part of a national effort to educate practitioners, with the support of various cardiology organizations, healthcare facilities and systems and medical technology vendors.

Guidelines offer a beginning

On a national level, help in determining the appropriate use of CCTA comes in the way of guidelines published in 2006. Last November, the American College of Cardiology Foundation (ACCF) along with the Society of Cardiovascular Computed Tomography (SCCT) and other key groups released “Appropriateness Criteria for Cardiac Computed Tomography and Cardiac Magnetic Resonance Imaging.” While not meant to be a federal standard, it provides a general basis of knowledge and direction.

“Developing appropriateness criteria and best practice guidelines for coronary CTA is essential. We need this technology adopted and incorporated in a way that benefits the patient and uses the best available evidence,” says DeFrance, who is a founding member of SCCT.

John Lesser, MD, FACC, an SCCT board member says, “Appropriateness guidelines are very important. They are developed based on the combination of literature and diverse expert opinion…and are designed to be frequently updated.” Lesser is a cardiologist at Abbott Northwestern Hospital in Minneapolis, Minn., where in January they installed a Siemens Medical Solutions Somatom Definition dual source CT scanner. Abbott Northwestern performed 5,000 cath lab procedures last year, and currently performs 12 to 17 coronary CTAs daily.

“Guidelines allow payors and physicians who do not have extensive experience in the technique to have confidence and knowledge about whether the technology is being used responsibly,” Lesser says.

Some insurance companies turn to the guidelines to determine payment for the procedure, which on average costs $1,200. Others, such as California Medicare, have drafted their own criteria to determine payment for the procedure. DeFrance says CVCTA follows “Medicare guidelines for California in terms of coverage indications. Most of these overlap with the appropriateness document.”

Good, old-fashioned judgment

But the guidelines are not designed to replace good, experienced physician judgment about which cardiac patients should undergo CTA. “I think it’s very difficult with these cardiac patients to strictly adhere to guidelines because there are so many variables from patient to patient,” says Radiologist James P. Earls, MD, vice president and medical director of Fairfax Radiological Consultants (FRC) in Fairfax, Va., who is director of FRC’s cardiac CT program, and co-director of the cardiac CT program at Inova