Diagnostic test shows potential to noninvasively identify significant coronary artery disease

August 26, 2012

Among patients with suspected or known coronary artery disease, use of a method that applies computational fluid dynamics to derive certain data from computed tomographic (CT) angiography demonstrated improved diagnostic accuracy vs. CT angiography alone for the diagnosis of ischemia, according to a study being published online by JAMA. The study is being released early to coincide with its presentation at the European Society of Cardiology Congress.

"Coronary computed tomographic angiography is a noninvasive anatomic test for diagnosis of coronary stenosis [narrowing of a blood vessel] that does not determine whether a stenosis causes ischemia [inadequate blood supply]. In contrast, fractional (FFR) is a physiologic measure of coronary stenosis expressing the amount of coronary flow still attainable despite the presence of a stenosis, but it requires an . Noninvasive FFR computed from CT (FFRCT) is a novel method for determining the physiologic significance of (CAD), but its ability to identify ischemia has not been adequately examined to date," according to background information in the article.

James K. Min, M.D., of the Cedars-Sinai Heart Institute, Los Angeles, and colleagues conducted a study to evaluate the performance of noninvasive FFRCT compared with an invasive FFR reference standard for diagnosis of ischemia. The study included 252 patients with suspected or known CAD from 17 centers in 5 countries who underwent CT, invasive (ICA), FFR, and FFRCT between October 2010 and October 2011. About 77 percent of patients had experienced angina within the last month. Ischemia was defined by certain criteria. Anatomically obstructive CAD was defined by a stenosis of 50 percent or larger on CT and ICA. Among 615 study vessels, 271 had less than 30 percent stenosis and 101 had at least 90 percent stenosis.

Among , 137 (54.4 percent) had an abnormal FFR as determined by ICA. The researchers found that the diagnostic accuracy for FFRCT plus CT was 73 percent, which did not meet a prespecified primary end point for accuracy (as pre-specified based on the lower limit of a calculated 95 percent confidence interval). By comparison, diagnostic accuracy of CT alone for detecting coronary lesions with stenosis of 50 percent or greater, was 64 percent. When comparing FFRCT alone with CT alone for detecting these lesions, FFRCT demonstrated superior discrimination.

"On a per-patient basis, , sensitivity, specificity, positive predictive value, and negative predictive value of FFRCT plus CT were 73 percent, 90 percent, 54 percent, 67 percent, and 84 percent, respectively," the authors write. They note that the sensitivity and negative predictive value of FFRCT were high, indicating a low rate of false-negative studies. "These diagnostic features of FFRCT may encourage a greater sense of diagnostic certainty that patients who undergo CT who have ischemia are not overlooked, such that clinicians may be confident in not proceeding to invasive angiography in patients with stenoses on CT when FFRCT results are normal."

"Taken together, these study results suggest the potential of FFRCT as a promising noninvasive method for identification of individuals with ."

In an accompanying editorial, Manesh R. Patel, M.D., of Duke University Medical Center, Durham, N.C., writes that future studies with the FFRCT technology "should be aimed at diagnostic strategies involving patients with varying pretest risks, thereby providing information on the incremental benefit from the test."

"Additionally, important comparison technologies beyond invasive angiography are needed, although improved access techniques and safety of invasive FFR may make it a plausible comparator. In addition to diagnostic performance, other outcomes of interest such as resource utilization and clinical outcomes should be captured. Finally, future studies will need to have local sites rather than core laboratories perform, analyze, and interpret the images to provide a sense of real-world function. It is with these types of continued rigorous studies that noninvasive technologies such as FFRCT plus CT may move the clinical community closer to the holy grail of a high-quality combined anatomic and functional test for detection of CAD that improves efficiency and patient outcomes."

Explore further: The next stage of heart function testing

More information:
doi:10.1001/2012.jama.11274
doi:10.1001/2012.jama.11383

Related Stories

The next stage of heart function testing

October 11, 2011
A new non-invasive technique for measuring how well the heart and blood vessels function in patients already suffering from coronary artery disease could, in a single test, identify which abnormally narrowed blood vessels ...

Recommended for you

Early study shows shoe attachment can help stroke patients improve their gait

December 14, 2017
A new device created at the University of South Florida – and including a cross-disciplinary team of experts from USF engineering, physical therapy and neurology – is showing early promise for helping correct the signature ...

Scientists rewrite our understanding of how arteries mend

December 13, 2017
Scientists from The University of Manchester have discovered how the severity of trauma to arterial blood vessels governs how the body repairs itself.

Deadly heart rhythm halted by noninvasive radiation therapy

December 13, 2017
Radiation therapy often is used to treat cancer patients. Now, doctors at Washington University School of Medicine in St. Louis have shown that radiation therapy—aimed directly at the heart—can be used to treat patients ...

Ultra-thin tissue samples could help to understand and treat heart disease

December 12, 2017
A new method for preparing ultra-thin slices of heart tissue in the lab could help scientists to study how cells behave inside a beating heart.

Young diabetics could have seven times higher risk for sudden cardiac death

December 12, 2017
Young diabetics could have seven times more risk of dying from sudden cardiac arrest than their peers who don't have diabetes, according to new research.

Research reveals how diabetes in pregnancy affects baby's heart

December 12, 2017
Researchers at the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA have discovered how high glucose levels—whether caused by diabetes or other factors—keep heart cells from maturing ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.