CT angiography and stress tests can predict heart attacks

Invasive angiography unnecessary?

Noninvasive CT angiography and CT myocardial stress perfusion imaging can adequately predict heart attacks and major adverse cardiovascular events, according to a study published yesterday in Radiologyno invasive coronary angiography (ICA) required.

Invasive coronary angiography (ICA), along with stress tests and single photon emission tomography (SPECT) imaging, has long been the "gold standard" for making determinations of whether a lesion is hemodynamically significant and likely to result in major adverse cardiovascular events, reads a Radiological Society of North America press release.

But this "gold standard" has its drawbacks—in costs and risk.

"The traditional approach with invasive catheterization requires that patients go to the hospital, get a catheter inserted into their leg and go in for the nuclear SPECT study on a different day," said coauthor Marcus Chen, MD, of the National Institutes of Health, in the press release.

"Invasive angiography is generally safe, but it can cause vascular problems in a significant number of patients, most commonly at site of the puncture," said lead author João A.C. Lima, MD, from Johns Hopkins Hospital and School of Medicine, in the release. "In rare cases, it can cause strokes or heart attacks. These risks are not trivial."

Study authors set out to prove that a non-invasive approach would be less costly, less risky and provide the same information as the invasive approach.

Changing the gold standard?

The study compared this traditional approach—ICA and SPECT stress tests—with a noninvasive approach—CT angiography and stress CT perfusion—and found both techniques to have "similarly high values for predicting MACE at two tears after presentation," reads the release.

"Our ensemble of findings clearly shows that a purely noninvasive anatomic and physiologic assessment is adequate in the assessment of patients suspected of having CAD," write the study authors. "Now with just one noninvasive test we can get two important but different pieces of information about the coronary arteries," said Dr. Chen in the release.

One benefit stands out—the noninvasive approach takes much less time.

In the study, CT angiography and stress CT perfusion could be performed at the same time, resulting in a median procedure time of 34 minutes. Compared to historical data for the invasive approach—30 minutes for ICA and an additional 120 minutes or more for SPECT stress testing—this is a significant reduction in time and related costs.

In the RSNA press release, doctors Lima and Chen suggest that this approach is safer, less expensive, preferred by patients and easy to learn.

"The study indicates that the technique is relatively easy to incorporate into existing practices: 15 of the 16 centers in the trial had never done the procedure before, according to Dr. Chen, and all we able to learn it effectively," reads the release.

"The noninvasive option should be a preferred or at least strongly considered option by cardiologists and radiologists managing these patients," said Dr. Lima in the release.

Of course, obstacles remain—not the least of which being that stress CT perfusion lacks a reimbursement code. Studies like this one, however, might contribute to reimbursement discussions, which were already "gaining momentum" last year, according to Radiology Today Magazine.

ACC Updates Appropriate Use Criteria

In other news, the American College of Cardiology and partner organizations released updated appropriate use criteria, last Friday, regarding coronary revascularization in patients with ischemic heart disease.

The update, "the second of a two-part revision for coronary revascularization," according to the press release, places a "greater emphasis on global risk assessments for future events and non-invasive testing results."

Specific changes include the replacement of a mandate for two antianginal drugs with a "step-wise use of antianginals" for medical therapy. "This starts ideally with a guidelines-directed beta-blocker as a first-line therapy, with other antianginals used to escalate therapy as clinically necessary," reads the release.

You can find the updated appropriate use criteria for coronary revascularization at the Journal of the American College of Cardiology website.

ACVP Blog previously created an infographic depicting the potential reduction in volume and $2.3 billion in cost savings for the healthcare system if the ACC's Appropriate Use Criteria for coronary revascularization were adopted nationwide.

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