Daisuke Yokota

Impact of Frequency-Domain Optical Coherence Tomography Guidance for Optimal Coronary Stent Implantation in Comparison With Intravascular Ultrasound Guidance

Background— Frequency-domain optical coherence tomography (FD-OCT) is a novel, high resolution intravascular imaging modality. Intravascular ultrasound (IVUS) is a widely used conventional imaging modality for achieving optimal stent deployment. The aim of this study was to evaluate the impact of FD-OCT guidance for coronary stent implantation compared with IVUS guidance. Methods and Results— A total of 70 patients with de novo coronary artery lesions and either unstable or stable angina pectoris were enrolled in this randomized study (optical coherence tomography [OCT] group: n=35, IVUS group: n=35). In the OCT group, stent implantation was performed under FD-OCT guidance alone and final stent expansion was evaluated by IVUS. In the IVUS group, conventional IVUS guidance was used and final stent apposition was evaluated by FD-OCT. There were no significant differences regarding the procedural, fluoroscopy time, and contrast volume. Although device and clinical success rates also were similar, the visibility of vessel border was significantly lower in the OCT group (P<0.05). Minimum and mean stent area and focal and diffuse stent expansion were smaller (6.1±2.2 mm versus 7.1±2.1 mm, 7.5±2.5 versus 8.7±2.4 mm, 64.7±13.7% versus 80.3±13.4%, 84.2±15.8% versus 98.8±16.5%, P<0.05, respectively), and the frequency of significant residual reference segment stenosis at the proximal edge was higher in the OCT group (P<0.05). Incomplete apposed struts in both groups were similar (P=0.34). Conclusions— FD-OCT guidance for stent implantation was associated with smaller stent expansion and more frequent significant residual reference segment stenosis compared with conventional IVUS guidance.

Morphological differences of tissue characteristics between early, late, and very late restenosis lesions after first generation drug-eluting stent implantation: an optical coherence tomography study

AIMS Restenosis of drug-eluting stents (DESs) might be different from that of bare metal stent restenosis in diverse ways including mechanisms and time course; however, these have not been fully examined. To gain insight into the mechanisms and time course of DES restenosis, we evaluated the characteristics of restenotic lesions of first generation DES using optical coherence tomography (OCT). METHODS AND RESULTS We compared the morphological characteristics of early in-stent restenosis (<1 year: E-ISR, n = 43), late ISR (1-3 years: L-ISR, n = 22), and very late ISR (>3 years: VL-ISR, n = 21). OCT qualitative restenotic tissue analysis included the assessment of tissue structure [homogeneous or four types of heterogeneous intima (thin-cap fibroatheroma (TCFA)-like, layered, patchy or speckled pattern)], the presence of the peri-strut low intensity area (PLIA), microvessels, disruption with cavity, and intraluminal material and was performed at every 1 mm slice of the entire stent length. In addition to a greater trend for heterogeneous intima at the later phase, TCFA-like pattern image, intra-intima microvessels were increased from the early to the very late phase. On the other hand, the speckled pattern image was decreased from the early to the very late phase. CONCLUSION The OCT morphological characteristics of DES restenotic tissue varied at different time-points. OCT images in early DES ISR might be associated with delayed arterial healing, and neoatherosclerosis might contribute to late catch-up phenomenon (L-ISR and VL-ISR) after DES implantation.

Impact of Cholesterol Metabolism on Coronary Plaque Vulnerability of Target Vessels: A Combined Analysis of Virtual Histology Intravascular Ultrasound and Optical Coherence Tomography

OBJECTIVES The aim of this study was to evaluate the relationship between cholesterol metabolism and coronary plaque vulnerability. BACKGROUND Cholesterol homeostasis, defined as the balance between absorption and synthesis, influences the progression of coronary atherosclerosis. METHODS Consecutive stable angina pectoris patients (N = 80) not receiving any lipid-lowering therapy were divided into 2 groups based on the presence of in vivo thin cap fibroatheroma (TCFA) in de novo target vessels assessed by the combined use of virtual histology intravascular ultrasound and optical coherence tomography. RESULTS Patients with in vivo TCFA (n = 42) showed a higher campesterol-to-lathosterol ratio (3.36 [interquartile range, 2.10 to 4.26] vs. 1.50 [1.20 to 2.50], p < 0.0001). The campesterol-to-lathosterol ratio, low-density lipoprotein (LDL) cholesterol, and high-sensitivity C-reactive protein (hsCRP) were positively correlated with the percentage of necrotic core volume (r = 0.520, p < 0.0001; r = 0.520, p < 0.0001; and r = 0.539, p < 0.0001, respectively) and negatively correlated with thinnest fibrous cap thickness (r = -0.566, p < 0.0001; r = -0.530, p < 0.0001; and r = -0.358, p = 0.007, respectively) . The independent predictors of the incidence of TCFA were the campesterol-to-lathosterol ratio (odds ratio: 3.989, 95% confidence interval: 1.688 to 9.428; p = 0.002), LDL cholesterol (odds ratio: 1.425, 95% confidence interval: 1.023 to 1.985; p = 0.03), hsCRP (odds ratio: 1.025, 95% confidence interval: 1.003 to 1.047; p = 0.02), and the percentage of necrotic core volume (odds ratio:1.084, 95% confidence interval: 1.012 to 1.161; p = 0.02). CONCLUSIONS Enhanced absorption and reduced synthesis of cholesterol may be related to coronary plaque vulnerability.

Impact on Optical Coherence Tomographic Coronary Findings of Fluvastatin Alone Versus Fluvastatin + Ezetimibe

Although lipid-lowering therapy with statin and ezetimibe has been reported to provide greater reduction in low-density lipoprotein cholesterol levels than statin monotherapy, the effect of supplemental therapy on plaque stabilization is yet to be fully elucidated. Cap thickness of fibroatheroma evaluated by optical coherence tomography (OCT) is a major determinant of vulnerable plaque. The primary objective of this study is to evaluate the effect of ezetimibe in addition to fluvastatin on the progression of coronary atherosclerotic plaque evaluated by OCT. Sixty-three patients with angina pectoris with intermediate, nonculprit, lipid-rich plaque lesions evaluated by OCT were enrolled. The patients were divided into 2 groups: ezetimibe (10 mg/day) + fluvastatin (30 mg/day), and fluvastatin (30 mg/day) alone, and serial OCT examinations were performed at baseline and 9-month follow-up. A total of 57 patients (ezetimibe + fluvastatin, n = 31; fluvastatin alone, n = 26) underwent serial OCT examinations. The change in low-density lipoprotein cholesterol level was significantly larger in the ezetimibe + fluvastatin group compared with fluvastatin-alone group (-34.0 ± 32.0 vs -8.3 ± 17.4 mg/dl, p <0.001). Fibrous cap thickness was significantly increased and the angle of the lipid plaque was significantly decreased in both groups. The change in the fibrous cap thickness was significantly greater in the ezetimibe + fluvastatin group (0.08 ± 0.08 mm vs 0.04 ± 0.06 mm, p <0.001). In conclusion, lipid-lowering therapy by ezetimibe + fluvastatin could increase the fibrous cap thickness of lipid-rich plaque compared with fluvastatin monotherapy.

PRIOR CORONARY ARTERY BYPASS GRAFTING DIMINISH THE INITIAL SUCCESS RATE OF PERCUTANEOUS CORONARY INTERVENTION TO THE CHRONIC TOTAL OCCLUSION IN THE NATIVE CORONARY ARTERY

Background: The epoch-making techniques for percutaneous coronary intervention (PCI) of the chronic total occlusions (CTO) such as retrograde approach and CART technique have contributed to the improvement of initial success of PCI to the CTO lesions, however, we are still forced to do complex procedures to recanalize the CTO lesions in the native coronary artery (NCA) in the prior coronary artery bypass grafting (CABG) patients. Thus, the purpose of this study is to compare the initial success rate of CTO lesions in NCA between the prior CABG patients and without CABG patients, and to speculate the affecting factors.

Response to Letter Regarding Article, “Impact of Frequency-Domain Optical Coherence Tomography Guidance for Optimal Coronary Stent Implantation in Comparison With Intravascular Ultrasound Guidance”

We appreciate the valuable comments by Garcia-Garcia et al regarding our article.1 We agree with the comments on our limitations about study design especially with regard to criteria of the procedure. First, the efficacy of distal protection devices in native coronary arteries is still controversial, and criteria regarding usage of this device are not defined yet. However, we believe this device could be helpful for prevention of distal embolus in certain cases as we have sometimes experienced, and optical frequency-domain imaging (OFDI) is helpful to predict such cases. Making use of the criteria of this study, …

LONG-TERM SERIAL ANGIOGRAPHIC OUTCOMES AFTER SIROLIMUS-ELUTING STENT IMPLANTATION: CONTEMPORARY PRACTICE IN REAL WORLD POPULATION

Methods: A total of 4,428 lesions were treated with sirolimus-eluting stent (SES) from June 2004 to Jun 2009 in our institution. Of those, 424 lesions without restenosis at early follow-up (9.5 ± 2.4 months, range: 6.3 to 25.6 months) had late follow-up angiography (22.3 ± 6.7 months, range: 24.2 to 50.1 months). We evaluated serial angiographic outcomes and predictors of late restenosis among patients treated with SES > 2 years after the index procedure.