Computed tomography angiography and myocardial computed tomography perfusion in patients with coronary stents: prospective intraindividual comparison with conventional coronary angiography

Abstract

Objectives: This study sought to determine whether adding myocardial computed tomography perfusion (CTP) to computed tomography angiography (CTA) improves diagnostic performance for coronary stents.

Background: CTA of coronary stents has been limited by nondiagnostic studies caused by metallic stent material and coronary motion.

Methods: CTA and CTP were performed in 91 consecutive patients with stents before quantitative coronary angiography, the reference standard for obstructive stenosis (≥50%). If a coronary stent or vessel was nondiagnostic on CTA, adenosine stress CTP in the corresponding myocardial territory was read for combined CTA/CTP.

Results: Patients had an average of 2.5 ± 1.8 coronary stents (1 to 10), with a diameter of 3.0 ± 0.5 mm. Significantly more patients were nondiagnostic for stent assessment by CTA (22%; mainly due to metal artifacts [75%] or motion [25%]) versus CTP (1%; p < 0.001; severe angina precluded CTP in 1 case). The per-patient diagnostic accuracy of CTA/CTP for stents (87%, 95% confidence interval [CI]: 78% to 93%) was significantly higher than that of CTA alone (71%, 95% CI: 61% to 80%; p < 0.001), mainly because nondiagnostic examinations were significantly reduced (p < 0.001). In the analysis of any coronary artery disease, diagnostic accuracy and nondiagnostic rate were also significantly improved by the addition of CTP (p < 0.001). CTA/CTP (7.9 ± 2.8 mSv) had a significantly lower effective radiation dose than angiography (9.5 ± 5.1 mSv; p = 0.005). The area under the receiver-operating characteristic curve for CTA/CTP (0.82, 95% CI: 0.69 to 0.95) was superior to that for CTA (0.69, 95% CI: 0.57 to 0.82; p < 0.001) in identifying patients requiring stent revascularization.

Conclusions: Combined coronary CTA and myocardial CTP improves diagnosis of CAD and in-stent restenosis in patients with stents compared with CTA alone. (Coronary Artery Stent Evaluation With 320-Slice Computed Tomography-The CArS 320 Study [CARS-320]; NCT00967876).

Keywords: CCA; CI; CT; CTA; CTP; ISR; QCA; ROC; computed tomography; computed tomography angiography; computed tomography perfusion; confidence interval(s); conventional coronary angiography; coronary angiography; coronary vessels; diagnostic accuracy; in-stent restenosis; quantitative coronary angiography; receiver-operating characteristic; stents.