Patency control of coronary stents

Abstract

The use of percutaneous intervention (PCI) for the treatment of ischemic coronary artery disease has expanded dramatically over the last two decades. Initially, balloon angioplasty offered an alternative to bypass surgery in focal lesions, but it involved a considerable risk of acute dissection, thrombosis, or late coronary re-stenosis. Continuous technical innovation has expanded the indications for PCI and reduced both the procedural risk and the occurrence of post-procedural re-stenosis. Nowadays, most interventions involve intra-coronary expansion of stents. Still, until the introduction of coated stents, neointimal hyperplasia caused clinically significant re-stenosis in at least 20% of patients (Kiemeneij 2001). Although the occurrence of re-stenosis may be less in the future with increasing use of drugeluting stents, the progression of atherosclerotic degeneration in the remaining coronary arteries is not affected (Morice 2002). Multi-slice spiral CT allows minimally invasive angiographic imaging of the coronary arteries. The diagnostic accuracy to detect coronary stenoses is good (Nieman 2001, Achenbach 2001), particularly in the absence of extensive vascular calcification and in patients with low heart rates: The introduction of 16-slice and 64-slice CT scanners with sub-millimeter resolution have resulted in further improvements (Nieman 2002, Ropers 2003, Leschka 2005). Patients who previously underwent PCI often developed recurrent symptoms due either to re-stenosis at the location of the previous obstruction or to progression of atherosclerosis at other sites. Post-PCI patients are more likely to require repeated angiographic coronary evaluation, so that a non-invasive technique would therefore be desired. Possible clinical indications for multi-slice coronary CTA could include suspected early occlusion of stents after the procedure, late in-stent restenosis, or progression of coronary artery disease in non-stented vessel segments. © 2007 Springer-Verlag Berlin Heidelberg.