Diagnostic accuracy of 64-slice computed tomography coronary angiography in a large population of patients without revascularisation: registry data on the impact of calcium score

Purpose

This study evaluated the diagnostic accuracy of computed tomography coronary angiography (CTCA) for detecting significant coronary artery stenosis (??50% lumen reduction) at different coronary calcium score (CACS) values with conventional coronary angiography (CAG) as the reference standard.

Material and methods

A total of 1,500 patients (928 men, mean age 58.2??12.5 years) in sinus rhythm who underwent CTCA (64-slice technology) and CAG were enrolled. Diagnostic accuracy and likelihood ratios (LR) of CTCA were evaluated against CAG for the total population and in different CACS classes (0; 1?C10; 11?C100; 101?C400; 401?C1,000; >1,000).

Results

The prevalence of obstructive disease was 51% (23.5% single vessel; 27.5% multivessel; progressive increase from 17.9% to 94% through the CACS classes). In the per-patient analysis, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of CTCA were 99%, 92%, 94% and 99%, respectively. Per-patient analysis showed a worse PPV of CTCA (76?C77%) in classes with low CACS (1?C10/11?C100). Per-patient LR were higher in classes with extreme CACS values (0 = LR+ 18.3 and LR? = 0.0; c1,000 = LR+ 17.0 and LR? = 0.0) with values always >7 for LR+ and <0.033 for LR? for all CACS classes.

Conclusions

CTCA is a reliable diagnostic modality, with high sensitivity and NPV regardless of CACS.