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

Laser device placed on the heart identifies insufficient oxygenation better than other measures

September 20, 2017
A new device can assess in real time whether the body's tissues are receiving enough oxygen and, placed on the heart, can predict cardiac arrest in critically ill heart patients, report researchers at Boston Children's Hospital ...

Metabolism switch signals end for healing hearts

September 19, 2017
Researchers have identified the process that shuts down the human heart's ability to heal itself, and are now searching for a drug to reverse it.

Beta blockers not needed after heart attack if other medications taken

September 18, 2017
A new study from the University of North Carolina at Chapel Hill finds beta blockers are not needed after a heart attack if heart-attack survivors are taking ACE inhibitors and statins. The study is the first to challenge ...

Which single behavior best prevents high blood pressure?

September 15, 2017
(HealthDay)—You probably already know that certain healthy lifestyle behaviors can reduce your risk of developing high blood pressure, but is any one behavior more important than the others?

RESPECT trial shows closing a small hole in heart may protect against recurrent stroke

September 13, 2017
A device used to close a small hole in the heart may benefit certain stroke patients by providing an extra layer of protection for those facing years of ongoing stroke risk, according to the results of a large clinical trial ...

Study shows so-called 'healthy obesity' is harmful to cardiovascular health

September 11, 2017
Clinicians are being warned not to ignore the increased cardiovascular health risks of those who are classed as either 'healthy obese' or deemed to be 'normal weight' but have metabolic abnormalities such as diabetes.

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.