CCTA with 64-slice effective in diagnosing three-vessel heart disease

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Cardiac CT angiography (CCTA) with 64-MDCT is highly accurate in diagnosing three-vessel disease, which is one of the potential candidates for coronary artery bypass surgery (CABG), according to a study presented at the 93rd annual meeting of the Radiological Society of North America (RSNA) this week in Chicago.

The study, “Diagnostic Accuracy of 64-slice CT in Detecting Three-vessel CAD: Potential Candidates for CABG” was conducted by Myungsoo Lee, MD, and colleagues at the department of radiology at the Research Institute of Radiological Science at the Yonsei University College of Medicine, Severance Hospital in Seoul, Korea.

CABG is the treatment of choice in the patients with three-vessel disease, according to the ACC/AHA 2004 Guidelines Update for CABG, published in Circulation in 2004. CABG is superior to percutaneous coronary intervention (PCI with DES) in the areas of death, target vessel failure and more adverse cardiovascular and cerebrovascular events, according to the researchers. 

CCTA is highly accurate in diagnosis of coronary artery disease, and the researcher predicted that CCTA could diagnose three-vessel disease with high accuracy. The current role of CCTA is to rule out of CAD when a patient does not need invasive coronary angiography (ICA) in intermediate-risk patients with symptoms. “If we can accurately diagnose three-vessel disease, ICA could be skipped before CABG,” according to Lee.

There were a total of 90 patients who underwent CCTA and CAG: consecutive 30 patients with one-vessel disease on CCTA; consecutive 30 patients with two-vessel disease on CCTA; and consecutive 30 patients with three-vessel disease on CCTA.

The exclusion criteria are previous stent insertion; previous CABG; heart rate higher than 70 bpm; severe heart rhythm irregularity; and previous history of side effects of iodinated contrast agent.

The analysis included the interpretation of CCTA, which was read by two experienced radiologists with more than four years experience in CCTA before ICA; the interpretation of ICA, which was read by cardiologists in routine clinical practice; a comparison of CCTA and ICA. The researchers “compared the result of CCTA and ICA in terms of the number of diseased vessels.” Sensitivity, specificity, positive and negative predictive value of CCTA in diagnosing three-vessel disease were calculated; and the proper choice of treatment modality in clinical practice in the study group was searched as well.

The researchers used CT scan protocols, using a Siemens Medical Solutions Somatom 64-slice CT scanner; pre-medication, including a beta blocker in patients with a heart rate higher than 65 bpm; a vasodilator in all patients; and contrast medical administration.

The study examined 60 patients without three-vessel disease, including 27 males, with a mean age of 64.4, hypertension of 41 (68 percent) and diabetes mellitus (DM) of 20 (33%). There were 30 patients with three-vessel disease, including nine males with a mean age of 62, hypertension of 21 (73 percent), and a DM of 17 (57 percent).

The treatment choice in 34 patients with three-vessel disease was ICA. The treatment modality, five had medical treatment, 14 had stent insertion and 14 CABG. One patient was recommended to undergo CABG, but refused.

Of the 14 patients who underwent CABG: more than 70 percent had stenosis in all three major vessels (12); more than 70 stenosis in left circumflex coronary artery (LCx) and the right coronary artery (RCA), with 50 to 70 percent stenosis. Of the 14 patients who underwent PTCA with stent insertion: one or more vessels with 50 to 70 percent stenosis (11) and more than 70 percent stenosis in all three major coronary artery but collateral among them was good, so only two major vessel stent were indicated. One major vessel without significant stenosis but had more than 70 percent stenosis in its major branch. In the five patients who only took medical treatment, all of them were symptom-free after taking the medications.

The researchers proved their hypothesis and the diagnostic accuracy of CCTA with MDCT for three-vessel disease.