Diagnostic accuracy of CT angiography to assess coronary stent thrombosis as determined by intravascular OCT.

CORONARY STENT THROMBOSIS REMAINS A POTENTIAL COMPLICATION AFTER STENT IMPLANTATION. Detection of intracoronary thrombus has been demonstrated with invasive imaging such as coronary angiography, intravascular ultrasound, angioscopy, and optical coherence tomography (OCT). Above all, OCT has an excellent diagnostic accuracy for intracoronary thrombus (1). However, OCT is a specialized research tool which requires complex procedures for image acquisition. Multidetector row computed tomography (MDCT) is a promising noninvasive method for the assessment of coronary artery disease (2). Recent technical improvements have significantly improved the potential of MDCT to visualize stents and assess the in-stent lumen. Although stent diameter, material, and design, as well as procedure characteristics substantially affect image analysis and interpretation, identification of luminal obstruction is usually possible in larger stents as long as the computed tomography (CT) dataset does not contain major artefacts. Thrombus will typically appear as a hypodense structure within the stent lumen. To evaluate diagnostic accuracy of MDCT for stent thrombosis, we performed 64-slice CT and OCT in 79 patients who presented at a mean interval of 24 h (18 to 43 h) after the onset of acute chest pain within 1 month after coronary stent implantation. Stent thrombosis was identified in 21 patients by OCT. CT correctly identified 20 patients with stent thrombosis but misclassified 5 patients: 4 patients with a false-positive interpretation of CT had stents with a diameter of 2.5 mm. One patient with a false-negative CT interpretation had a small thrombus with diameter < 1.0 mm in OCT. The sensitivity, specificity, and positive and negative predictive values of CT for the identification of stent thrombosis were 95%, 93%, 83%, and 98%, respectively. Figures 1 and 2 show representative findings of stent thrombosis with incomplete occlusion, Figures 3 and 4 demonstrate complete thrombotic occlusion, and Figure 5 a false-positive CT dataset. It is important to be familiar with the described features, especially when considering CT imaging in patients with chest pain early after coronary stent implantation.