%0 Journal Article
%T CT Imaging of Coronary Stents: Past, Present, and Future
%A Andreas H. Mahnken
%J ISRN Cardiology
%D 2012
%R 10.5402/2012/139823
%X Coronary stenting became a mainstay in coronary revascularization therapy. Despite tremendous advances in therapy, in-stent restenosis (ISR) remains a key problem after coronary stenting. Coronary CT angiography evolved as a valuable tool in the diagnostic workup of patients after coronary revascularization therapy. It has a negative predictive value in the range of 98% for ruling out significant ISR. As CT imaging of coronary stents depends on patient and stent characteristics, patient selection is crucial for success. Ideal candidates have stents with a diameter of 3£¿mm and more. Nevertheless, even with most recent CT scanners, about 8% of stents are not accessible mostly due to blooming or motion artifacts. While the diagnosis of ISR is currently based on the visual assessment of the stent lumen, functional information on the hemodynamic significance of in-stent stenosis became available with the most recent generation of dual source CT scanners. This paper provides a comprehensive overview on previous developments, current techniques, and clinical evidence for cardiac CT in patients with coronary artery stents. 1. Rationale for CT Imaging of Coronary Stents Coronary artery stenting was pioneered in the mid 1980s [1]. It rapidly replaced ¡°plain old balloon angioplasty¡± for coronary revascularization and became the most commonly used revascularization technique in obstructive coronary artery disease. The major drawback of coronary artery stenting is the occurrence of in-stent restenosis (ISR), which has been reported to occur in 11 to 46% at 6 months in bare metal stents (BMS) [2]. With introduction of drug eluting stents (DES), early ISR became less common and nowadays about 76% of revascularizations are performed using DES [3]. However, ISR still poses a major problem in coronary revascularization therapy with more than 200.000 estimated cases of DES ISR in the US alone. Late catchup in ISR when using DES has also been discussed [4, 5]. Moreover, in-stent thrombosis has been identified as a relevant problem in DES [6]. Another potential late complication of DES is the occurrence of stent fractures. The latter is considered a predisposing factor for ISR and late thrombosis. Coronary stent fractures are diagnosed in about 3% of patients [7], but autopsy data reports a much higher frequency of up to 29% [8]. While acute in-stent thrombosis typically becomes symptomatic with chest pain, the detection of ISR is more problematic as patients are often asymptomatic and about half of the patients with significant ISR do not experience any symptoms [9]. In
%U http://www.hindawi.com/journals/isrn.cardiology/2012/139823/