Forty-two diagnostic accuracy studies (5,390 participants) and 11 patient outcome studies (1,483 participants) were included in the review. Most test accuracy studies were small (less than 100 participants), range 30 to 1,372. Spectrum bias (due to the high prevalence of coronary artery disease) was considered to be present in two thirds of the included test accuracy studies. Other frequently failed criteria were information on study withdrawals and observer variation.
Intention-to-diagnose analyses resulted in pooled estimates of sensitivity 98% (95% CI 96 to 99%), Ι²=59.8% and specificity 85% (95% CI 81 to 89%), Ι²=82,5%. When non-diagnostic coronary CT angiography results were excluded from the analysis, the pooled estimate of specificity was 88% (95% CI 85 to 91%) and sensitivity did not change.
There was no evidence of a threshold effect. Age was the only significant variable in the meta-regression. Subgroup analyses indicated that sensitivity was unaffected by age and specificity decreased with age (91% in studies with a mean participant age under 59 years and 77% in studies with a mean participant age over 62 years).
Of the 11 patient outcome studies, only two provided a comparison of coronary CT angiography with standard care; most were case series or retrospective cohort studies that compared major cardiovascular event rates in patients with positive and negative coronary CT angiography results. There was some indication (mainly from emergency department studies) that triage of low-risk patients using coronary CT angiography produced no serious adverse outcomes and was time-saving compared to usual care.