Abstract 3825: Spiral Coronary CT Angiography as a Screening Tool in Asymptomatic Population: a Troubleshooter or Troublemaker?
OBJECTIVES: Recent reports demonstrated that spiral coronary CT angiography (CCTA) showed promise for noninvasive detection of coronary stenosis in various subsets of patients. However, there is a paucity of information on the role of CCTA in asymptomatic population. This study sought to assess the impact of CCTA on management in asymptomatic population.
METHODS: We enrolled 1,165 asymptomatic consecutive subjects (mean age 49.1 ± 9.5 years, 63% men, and mean Framingham risk score (FRS) 7.4 ± 6.6%) who underwent CCTA as a part of health check between 2004 and 2006. Five hundreds and eighty-seven (50.5%) subjects underwent exercise treadmill test together in programs. End points included (1) identification of subjects with coronary artery disease (CAD) on coronary angiography (CAG) and (2) performance of any second diagnostic test (ST) within 90 days of index CCTA.
RESULTS: Among 192 (16.5%) subjects who had abnormal CCTA findings, 66 (5.7%) subjects had hemodynamically significant stenosis. A ST after CCTA was performed in 75 (6.4%) patients (in 31, CAG; in 44, myocardial perfusion scintigraphy, followed by CAG in 8). Of the 31 patients who underwent CAG, CAD was detected in 21 patients (1.9%) and 13 (1.1%) of them had undergone revascularization therapy. The most powerful predictor of referral to ST was the severity of stenosis on CCTA (OR 19.5, 95% confidence interval [9.9 - 38.6], p<0.001). Dividing the whole population according to FRS, incidence of significant stenosis on CCTA and referral rates to ST were similar in high-and intermediate-risk group, but was significantly lower in low-risk group (significant stenosis: 11.9% vs. 11.9% vs. 2.9%; secondary test: 13.1% vs. 10.2% vs. 3.6%, all p<0.05, respectively). Comparing with age, sex-matched population, not performing CCTA, the referral rates to ST of CCTA group was significantly higher only in high-risk subjects (13.1% vs 4.0%, p=0.024).
CONCLUSIONS: In asymptomatic population, the prevalence of CAD on CCTA was 5.7%. Even in asymptomatic population, especially those with high-risk group, CCTA had a significant impact on screening and managing occult CAD. However, CCTA had no impact on patient management and might be harmful considering radiation hazard in those with low to intermediate risk.