Cardiac CT angiography can guide patient management

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Putting cardiac CT angiography (CCTA) into the care matrix early allows for better patient management than any other non-invasive imaging exam, according to James K. Min, MD. In particular, CCTA allows a physician to confidently rule out obstructive coronary artery disease, provides higher sensitivity in some instances than nuclear myocardial perfusion imaging, and is cost effective in comparison with other diagnostic regimens, he noted.

Min, who works as an assistant professor of medicine in the division of cardiology, an assistant professor of radiology and is director of cardiac CT at Weill Cornell Medical College at New York Presbyterian Hospital in New York City, presented his thoughts on CCTA utilization at the 2008 American College of Cardiology  scientific conference in Chicago earlier this month.

According to Min, using CCTA—which relies heavily on advanced visualization technologies—is both highly accurate and cost-effective for the diagnosis of obstructive coronary disease. In a multicenter trial examining the diagnostic performance of CT scans that he cited, researchers found 95 percent sensitivity for the diagnosis of obstructive coronary artery disease and 99 percent accuracy for determining the absence of disease.

Another research study cited by Min found that CCTA can prevent unnecessary catheterization in patients with abnormal stress tests. In that multicenter trial, CCTA helped avoid catheterizations in 69 percent of the patients with persistent symptoms and an abnormal stress test.

A study conducted by Min and his colleagues at Cornell found that among patients undergoing both myocardial perfusion imaging (MPI) and CCTA, more than 10 percent of the cohort with normal MPI results were shown to have obstructive coronary artery disease via either CCTA or invasive angiography. They found that CCTA is to be of diagnostic utility for assessing coronary anatomy in patients with normal MPI but abnormal stress ECG results.

“I think the argument can be made that there’s no better non-invasive diagnostic test for the detection and exclusion of coronary artery disease,” Min stated.

Min holds that CCTA should be viewed by ordering clinicians as imaging for prevention as well as imaging for possible intervention. He believes that the exam should not only be used to rule out coronary artery disease, but should also help predict outcomes.

“I would make the argument that if CT is to be used for the evaluation of patients with suspected coronary artery disease it should not only detect coronary stenoses, but it should also predict their physiologic significance,” he said.

Min and fellow researchers at Cornell have sought to advance that goal.

In a study cohort of 176 adults free of cardiovascular disease (CVD) from a patient population of 1,168 consecutive CT scans over a period of two years, the scientists worked to establish reference standards for left ventricular hypertrophy (LVH) and LV geometry for the modality. They not only defined normal limits of LV mass with CCTA, they also found a high prevalence of LVH and abnormal LV geometry among hypertensive and obese (a body mass index greater than 30) in adults otherwise free of CVD.

“CCTA provides earlier detection of disease than other modalities and thereby allows us to treat these patients at a point in time before coronary stenoses progresses,” Min said.