Stent Stenosis After Percutaneous Coronary Intervention

Background: Coronary artery stenosis is the leading cause of mortality worldwide. Most of the patients are treated with percutaneous coronary intervention (PCI). Inserted stents may themselves develop stenosis and result in ischemic cardiac events. Objectives: In this presentation, we want to assess the frequency of stent stenosis among a large group of patients underwent the PCI using the 64-multidetector CT scan. Patients and Methods: Over a period of 6 years (2007-2012), a total of 2525 patients were referred to two university affiliated multislice CT scan centers (a GE 64 multislice CT scan machine and a Siemens 256 multislice machine) for cardiac CT angiography. The patients were referred because of some clinical symptoms or signs or due to control imaging after an intervention (CABG or PCI). Among these patients, 243 had at least one stent (in LAD, LCx or RCA) who were enrolled into the study. Standard image reconstruction was performed, and the coronary angiography was done for all patients. Stents were assessed for stenosis in reformatted images. The three above-mentioned vessels were assessed in terms of main anatomical parts such as proximal, middle and distal portions. Results: Mean age of the patients was 58.2 + 11.6 years old. 167 patients were male (68.7%). 166 stents (68.3%) had been placed in the LAD, 73 stents (30%) in the LCx and 74 stents (31.5%) in the RCA. Among 87 stents of the proximal portion of the LAD, distribution of normal, mild stenosis, moderate stenosis, severe stenosis, and complete occlusion were 58 (66.7%), 12 (13.8%), 6 (6.9%), 8 (9.2%) and 3 (3.4%) respectively. Among 61 stents of the middle portion of the LAD, distribution of normal, mild stenosis, moderate stenosis, severe stenosis, and complete occlusion were 53 (86.9%), 4 (6.6%), 1 (1.6%), 2 (3.3%) and 1 (1.6%), respectively. Eight cases of stent in distal portion of LAD were all normal (100%). Among all stents in other parts of the LAD, 1 had mild stenosis and 1 had complete occlusion. Among 19 stents of the proximal portion of the LCx, distribution of normal, mild stenosis, moderate stenosis and severe stenosis were 16 (84.2%), 1 (5.3%), 1 (5.3%) and 1 (5.3%), respectively. Among 27 stents of the middle portion of the LCx, 22 were normal (81.5%), 4 had moderate stenosis (14.8%), and one had severe stenosis (3.7%) All six stents of distal LCX were normal. Among stents inserted in other parts of the LCx, one had moderate stenosis, 2 had severe stenosis and 3 had complete occlusion. Among 37 stents of the proximal portion of the RCA, distribution of normal, mild stenosis, moderate stenosis and severe stenosis were 27 (73%), 4 (10.8%), 1 (2.7%) and 5 (13.5%) respectively. Among 28 stents of the middle portion of the RCA, distribution of normal, mild stenosis, moderate stenosis, and severe stenosis were 21 (75%), 1 (3.6%), 2 (7.1%) and 4 (14.3%), respectively. All 4 stents in the distal portion of the RCA and 5 stents in other parts of the RCA were normal. Conclusions: The rate of stenosis in stents is considerable and needs special attention when the patients are evaluated clinically.