Coronary angiography is currently the best diagnostic test for suspected coronary artery disease (CAD), but the risks and patient discomfort associated with this procedure have encouraged research into less invasive alternatives. Multidetector CT (MDCT) has emerged as an effective means of assessing the coronary arteries, but until recently has only been evaluated in single-center studies.OBJECTIVES
To evaluate the sensitivity and specificity of 16-row MDCT in the diagnosis of CAD.DESIGN
The Coronary Assessment by Computed Tomographic Scanning and Catheter Angiography (CATSCAN) trial was a prospective study conducted at centers in Argentina, Germany, Israel, Japan, The Netherlands, UK, (one center each) and US (five centers) between June 2004 and March 2005. Patients aged 30-70 years scheduled to have coronary angiography for evaluation of chest pain or because of suspected CAD were enrolled in this study. Patients who had undergone previous CABG surgery and women of reproductive age were not enrolled. Other exclusion criteria included the presence of a cardiac pacemaker or defibrillator, renal insufficiency, diabetes requiring medication, a BMI greater than 40, myocardial infarction within the 30 days before enrollment, and contraindications to iodine contrast or β-blockers.INTERVENTION
Initially, a noncontrast MDCT was performed to assess the extent of coronary artery calcification. Patients with an Agatston calcium score of less than 600 then underwent 16-row MDCT coronary angiography with iodine contrast-enhancement. Standard angiography was carried out in all patients 1-14 days after MDCT.OUTCOME MEASURES
The main outcomes were segment-based and patient-based sensitivity and specificity for the detection of coronary artery stenosis (CAS) of more than 50% and more than 70% of luminal diameter.RESULTS
Among the 238 patients enrolled in the study (mean age 60 years, 68% were male), 187 had a calcium score of less than 600 and underwent analysis. In total, 1,629 nonstented coronary artery segments with a diameter of more than 2 mm were identified. Stenosis of more than 50% was detected by standard coronary angiography in 89 segments in 59 of the 187 patients. In total, 1,157 (71%) of the 1,629 segments were successfully evaluated by MDCT; sensitivity and specificity for identifying stenosis of more than 50% were 89% (95% CI 82-95%) and 65% (95% CI 62-67%), respectively. The positive predictive value was 13% (95% CI 10-15%) and the negative predictive value was 99% (95% CI 98-100%). The sensitivity and specificity of MDCT for identifying stenosis of more than 70% were 94% (95% CI 87-100%) and 67% (95% CI 65-70%), respectively, with a positive predictive value of 6% (95% CI 4-6%) and a negative predictive value of 99% (95% CI 98-100%).CONCLUSION
The authors concluded that while MDCT could have clinical application in selected patients with inconclusive stress-test results, it should not be adopted as a routine first-line diagnostic test in all patients with suspected CAD.