Diagnostic accuracy and clinical utility of noninvasive testing for coronary artery disease.

BACKGROUND: Computed tomography coronary angiography (CTCA) has become a popular noninvasive test for diagnosing coronary artery disease. OBJECTIVE: To compare the accuracy and clinical utility of stress testing and CTCA for identifying patients who require invasive coronary angiography (ICA). DESIGN: Observational study. SETTING: University medical center in Rotterdam, the Netherlands. PATIENTS: 517 patients referred by their treating physicians for evaluation of chest symptoms by using stress testing or ICA. INTERVENTION: Stress testing and CTCA in all patients. MEASUREMENTS: Diagnostic accuracy of stress testing and CTCA compared with ICA; pretest probabilities of disease by Duke clinical score; and clinical utility of noninvasive testing, defined as a pretest or posttest probability that suggests how to proceed with testing (no further testing if < or =5%, proceed with ICA if between 5% and 90%, and refer directly for ICA if > or =90%). RESULTS: Stress testing was not as accurate as CTCA; CTCA sensitivity approached 100%. In patients with a low (<20%) pretest probability of disease, negative stress test or CTCA results suggested no need for ICA. In patients with an intermediate (20% to 80%) pretest probability, a positive CTCA result suggested need to proceed with ICA (posttest probability, 93% [95% CI, 92% to 93%]) and a negative result suggested no need for further testing (posttest probability, 1% [CI, 1% to 1%]). Physicians could proceed directly with ICA in patients with a high (>80%) pretest probability (91% [CI, 90% to 92%]). LIMITATIONS: Referral and verification bias might have influenced findings. Stress testing provides functional information that may add value to that from anatomical (CTCA or ICA) imaging. CONCLUSION: Computed tomography coronary angiography seems most valuable in patients with intermediate pretest probability of disease, because the test can distinguish which of these patients need invasive angiography. These findings need to be confirmed before CTCA can be routinely recommended for these patients.

Comparison of frequency of calcified versus non-calcified coronary lesions by computed tomographic angiography in patients with stable versus unstable angina pectoris.

Computed tomographic coronary angiography (CTCA) can noninvasively identify calcified and noncalcified coronary plaques. The aim of this study was to compare the phenotypes of all plaques and of culprit plaques between patients with unstable angina pectoris (UAP) and those with stable angina pectoris (SAP), because plaque characteristics may differ between these patients. In 110 patients with UAP and 189 with SAP from a multicenter study comparing 64-slice CTCA with conventional coronary angiography, the number and phenotypes (noncalcified, mixed, and calcified) of coronary plaques were compared. In a subanalysis in 50 patients with UAP and 64 with SAP, culprit plaque characteristics, including culprit plaque cross-sectional area relative to total vessel cross-sectional area, culprit plaque length, remodeling index, and spotty calcification, were determined. Odds ratios for the presence of UAP, adjusted for clinical variables and the total number of plaques, were calculated for plaque characteristics on CTCA. Although the number of plaques was similar for patients with UAP and those with SAP, plaques in patients with UAP were more frequently noncalcified than in patients with SAP. The odds ratio for UAP was 1.3 (95% confidence interval [CI] 1.1 to 1.5) per noncalcified plaque. In the culprit plaque subanalysis, odds ratios for UAP were 0.99 (95% CI 0.96 to 1.01) per millimeter culprit plaque length, 2.7 (95% CI 1.2 to 6.4) for noncalcified culprit plaque, and 1.06 (95% CI 0.99 to 1.13) per percentage relative culprit plaque cross-sectional area. No significant relation was found between remodeling index or spotty calcification and UAP. In conclusion, noncalcified plaques and large noncalcified culprit plaques are more frequently found in patients with UAP than in those with SAP.