Additional value of dipyridamole stress myocardial perfusion by 64-row computed tomography in patients with coronary stents

BackgroundCoronary computed tomography angiography (CTA) is a well-established diagnostic tool for coronary artery disease (CAD). However, coronary segments with prior stent implantation visualized with CTA may have limited evaluation and reduced accuracy.ObjectiveWe assessed the incremental value of stress myocardial CT perfusion (CTP) over anatomical assessment by coronary CTA alone in patients with stents, using quantitative invasive coronary angiography (≥50%) as reference.MethodsForty-six patients (56.9 ± 7.2 years; 28 men) referred to invasive coronary angiography were evaluated, combining coronary CTA and dipyridamole stress myocardial CTP with 64 detector-row CT. Coronary CTA was evaluated for ≥50% coronary stenosis, and myocardial CTP was used to potentially reclassify coronary territories, including those with stents and poorly evaluated stents because of artifacts.ResultsWe evaluated 138 coronary territories, 62 with ≥1 stent. From these, 21 (34%) territories had adequately evaluated stents, 28 (45%) had limitedly evaluated stents still allowing diagnosis, and 13 (21%) had inadequately evaluated stents (no luminal assessment possible). Sensitivity, specificity, positive predictive value, negative predictive value and accuracy for coronary CTA in stent territories were, respectively, 85%, 77%, 87%, 74%, and 81%, and the combined use of coronary CTA and myocardial CTP were 88%, 95%, 97%, 81%, and 91% (P = 0.0292). In territories with impaired stent evaluation (limited or inadequate), the diagnostic performance of coronary CTA alone was 83%, 72%, 79%, 76% and 77%, and combined with myocardial CTP were 87%, 94%, 95%, 85%, and 91% (P = 0.036).ConclusionThe combined evaluation of coronary CTA and stress myocardial CTP improved the diagnostic accuracy for the detection of significant obstructive CAD in patients with stents.