Iwao Goto

Clinical and pathological characteristics of homogeneous and nonhomogeneous tissue of in-stent restenosis visualized by optical coherence tomography.

BackgroundAlthough it is known that in-stent restenosis (ISR) patterns appear homogeneous or nonhomogeneous by optical coherence tomography (OCT), interpretations of the ISR inflammatory response, of the OCT image, and its pathological implications are unclear. The aim of this study was to use OCT to characterize ISR and its inflammatory index in patients after coronary stenting. MethodsOCT was performed at follow-up in 100 angiographic ISR lesions. ISR lesions were divided into two groups: (a) homogeneous (n=48) and (b) nonhomogeneous (n=52) image groups. We assessed the ISR images produced by OCT for tissue heterogeneity and neo-intimal hyperplasia using the normalized standard deviation of OCT signal-intensity (OCT-NSD) observed in neo-intimal hyperplasia tissue. In some patients with a nonhomogeneous OCT image, we collected pathological tissue. ResultsThe prevalence of drug-eluting stents was 48% in the nonhomogeneous group and 29% in the homogeneous group (P=0.05). The OCT-NSD value in the nonhomogeneous group (0.223±0.019) was significantly higher than that in the homogeneous group (0.203±0.025; P<0.0001). Pathological tissue showed fibrin thrombi with infiltrating macrophage in 12 cases of nonhomogeneous ISR. The area under the receiver operating characteristic curve for the prediction of a nonhomogeneous image was 0.73 for OCT-NSD (95% confidence interval: 0.62–0.83: P<0.0001). The odds ratio for the prediction of a nonhomogeneous image was 3.47 (95% confidence interval: 1.18–10.2: P=0.02) for smoking by logistic regression analysis. ConclusionNonhomogeneous ISR visualized by OCT showed a high OCT-NSD value, which was a useful predictor for nonhomogeneous images. Moreover, the nonhomogeneous ISR image visualized by OCT may show chronic inflammation and fibrin thrombi.

“Intracoronary Whirling Current Phenomenon” and Thrombus Formation After Sirolimus-Eluting Stent Implantation Visualized by Optical Coherence Tomography

We present a case of imaged “intracoronary whirling current phenomenon.” A 60-year-old Japanese man was treated with 2 sirolimus-eluting stents (SES; 3.0×18 and 3.5×33 mm) in the right coronary artery (RCA) for chronic total occlusion in October 2007. After percutaneous coronary intervention, he was taking 200 mg of aspirin and 200 mg of ticlopidine. However, he had recurrent transient ischemic chest pain beginning at 7 months. A second coronary angiography at 8 months after SES implantation showed reocclusion at a site just proximal to the SES. A repeat percutaneous coronary intervention was performed for RCA chronic total occlusion (Figure 1). After crossing the guide wire to the distal portion of the RCA, the target lesion was dilated using a 1.25×10 mm balloon catheter. After minimum balloon dilatation, optical coherence tomography (OCT) was performed to evaluate in-stent reocclusion from the distal portion to the proximal portion (Figure 2). Two different types of tissue coverage (may be consistent with thrombus formations of different ages) were observed in the stent reocclusion.1 Moreover, in the patent distal portion of the RCA, an intracoronary whirling current …

Chronic thrombus occlusion after bare metal stenting in a patient with acute coronary syndrome visualized by optical coherence tomography

We present a case of chronic thrombus occlusion visualized by optical coherence tomography (OCT) in a patient following bare metal stent (BMS) implantation. A 74-year-old Japanese man was treated with single BMS implantation for acute coronary syndrome. The second follow-up angiography demonstrated no restenosis at the BMS site in the convalescent phase before discharge. A third coronary angiography at 6 months after BMS implantation showed sub-total occlusion at a site just proximal to the BMS. OCT was performed to evaluate in-stent restenosis. OCT demonstrated an organized thrombus-like image containing a micro-channel in the target lesion. Repeat percutaneous coronary intervention (PCI) was performed with a distal protection device and we were able to aspirate some tissue from the culprit lesion. Pathological examination of this tissue revealed an organized fibrin thrombus with angiogenesis. Phosphotungstic acid hematoxylin staining and CD68 immunological staining were positive in this tissue. Moreover, immunological staining for CD34 was positive in the micro-channel of this tissue, suggesting chronic build up. This case demonstrated that chronic, organized thrombus formation is a possible cause of restenosis after BMS implantation in the convalescent phase, and that OCT is a useful modality to discriminate thrombus formation from regular neo-intimal hyperplasia in in-stent restenosis lesions.