Non-invasive computed tomography angiography in the assessment of coronary stent patency: an Australian experience

This study aimed to evaluate the feasibility and accuracy of 16-slice computed tomography (CT) in the assessment of coronary stent patency. CT coronary angiography (CA) has a high degree of accuracy in the assessment of coronary artery disease compared with invasive selective CA. However, its accuracy in the evaluation of stent patency is not well investigated.

We conducted a retrospective observational study of paired CT coronary angiography (CT-CA) and invasive fluoroscopic coronary angiography (FCA) in 37 patients with 47 coronary stents. CT-CA was carried out with an electrocardiogram-gated 16-slice CT (LightSpeed-16, General Electric (GE), WI, USA). Two CT reporters, blinded to the FCA findings, assessed CT images for stent patency. A cardiologist blinded to CT findings reported FCA. FCA was regarded as the reference standard.

A CT-CA could assess 45 of 47 coronary stents (96%). Non-assessable stents on CT-CA were due to motion artefacts and stent-blooming effects. Of those 45 assessable stents, CT-CA correctly identified five out of seven stents with binary in-stent restenosis (ISR) and 37 of 38 stents without binary ISR. The sensitivity and specificity of 16-slice CT in the evaluation of coronary stents for binary ISR were 71% (95% confidence interval (CI) (29%, 96%)) and 97% (95%CI (86%, 100%)), respectively, exclusive of non-assessable stents. The positive and negative predictive values of 16-slice CT were 83% (95%CI (36%, 100%)) and 95% (95%CI (83%, 99%)), respectively.

Sixteen-slice CT has a low sensitivity, but very a high specificity when compared with FCA in the evaluation of coronary stents for ISR.