Although survival after heart transplantation (HTx) has improved in recent years, cardiac allograft vasculopathy (CAV) is still the leading cause of remote morbidity and mortality in HTx recipients, partly because of difficulty with its diagnosis. In general, routine surveillance for CAV is advocated with coronary angiography accompanied by intravascular ultrasound (IVUS) if necessary. However, these modalities have limitations with respect to low spatial resolution, and sufficient qualitative/quantitative assessment of coronary intima has not been accomplished. Recently, optical coherence tomography (OCT) has emerged as a novel intracoronary imaging technique using an optical analogue of ultrasound with a spatial resolution of ...

The purpose of this study was to determine the effect of PRG filler extraction solution on the demineralization of enamel using optical coherence tomography (OCT). Bovine enamel was treated with lactic acid buffer solution and then placed in artificial saliva (De group). In the second group, specimens were stored in PRG filler extraction solution followed by immersion in lactic acid buffer solution (PRG group). In the control group, specimens were simply stored in artificial saliva. From the OCT image, the peak intensity (dB) and width at (1/e 2 ) were obtained, and the integrated value was calculated. The data were ...

We report a patient’s case of slow progressive in-stent restenosis 10 years after bare-metal stent implantation to his carotid artery. We treated the patient with an additional stent placement under a distal filter protection device. Optical coherence tomographic assessment and plaque histology during the carotid artery stenting (CAS) revealed atheromatous change at in-stent neointima, which contained lipid-rich plaque and calcification deposits. These findings suggest that in-stent neoatherosclerosis may play an important role in the pathogenesis of very late stent restenosis after CAS.

The objective of this study was to determine the efficacy of Swept Source Optical Coherence Tomography (SS-OCT) imaging in assessing a novel fissure caries model. Samples were imaged by both near infrared based SS-OCT and high resolution x-ray tomography imaging to non-destructively quantify artificial lesions. The mean relative reflectivities of the demineralized fissures were at least 6 times higher than the corresponding sound fissures ( p <0.02). Importantly, this study demonstrated that SS-OCT reflectivity images can be used to predict the depth of fissure demineralization. Despite correctly evaluating the depth, this work showed that the lesion width calculated from SS-OCT ...

Although the early failure of drug-eluting stents (DES) is mainly associated with procedural factors, the mechanism for late DES failure has not been fully clarified...

Background:  Although both optical coherence tomography (OCT) and angioscopy are robust tools for detecting intrastent thrombi and neoatherosclerosis in vivo, whether OCT findings are comparable with angioscopy findings remains unclear. Methods and Results:  22 patients presenting with de novo lesions underwent 26 sirolimus-eluting stent (SES) implantations, with follow-up OCT and angioscopy at 10 months post-implantation for segmental assessment of the proximal, mid-, and distal SES segments (66 segments). The mean signal intensity index (signal intensity of the neointima/signal intensity of fibrous intimal hyperplasia) was quantified for angioscopically detected in-stent yellow and white segments. The detection rate for red thrombi ...

We report the case of a 69-year-old male whose left circumflex coronary artery was perforated immediately after implantation of an Endeavor zotarolimus-eluting stent (E-ZES). Despite successful hemostasis by long balloon inflation, a coronary pseudoaneurysm remained at the E-ZES-implanted segment. Coronary angiography performed one year after the coronary perforation showed the pseudoaneurysm had disappeared. Simultaneous optical coherence tomography and coronary angioscopy revealed that stent struts of the E-ZES were fully covered with thick neointima. This is the first case report of a relatively rapid healing process for an E-ZES-related coronary pseudoaneurysm.

Since its invention in the late 1990s, intravascular optical coherence tomography (OCT) has been rapidly adopted in clinical research and, more recently, in clinical practice. Given its unprecedented resolution and high image contrast, OCT has been used to visualize plaque characteristics and to evaluate the vascular response to percutaneous coronary intervention. In particular, OCT is becoming the standard modality to evaluate in vivo plaque vulnerability, including the presence of lipid content, thin fibrous cap, or macrophage accumulation. Furthermore, OCT findings after stent implantation, such as strut apposition, neointimal hyperplasia, strut coverage, and neoatherosclerosis, are used as surrogate markers of the ...

Background: Coronary artery calcification (CAC) presents unique challenges for percutaneous coronary intervention. Calcium appears as a signal-poor region with well-defined borders by frequency-domain optical coherence tomography (FD-OCT). The objective of this study was to demonstrate the accuracy of intravascular FD-OCT to determine the distribution of CAC. Methods and Results: Cadaveric coronary arteries were imaged using FD-OCT at 100-μm frame interval. Arteries were subsequently frozen, sectioned and imaged at 20-μm intervals using the Case Cryo-Imaging automated system TM . Full volumetric co-registration between FD-OCT and cryo-imaging was performed. Calcium area, calcium-lumen distance (depth) and calcium angle were traced on every ...

Frequency-domain optical coherence tomography (FD-OCT) is a novel technology which provides high-resolution cross-sectional images of coronary arteries. The aim of this study was to evaluate the inter-scan reproducibility of geometric FD-OCT measurements in the clinical setting. We examined 20 coronary lesions using FD-OCT. Following the FD-OCT image acquisition (1 st pullback), and after the disengagement and re-engagement of the guiding catheter, an additional acquisition (2 nd pullback) was performed using a new FD-OCT catheter. There was excellent correlation for minimum lumen area ( r = 0.99, P < 0.001), lesion length ( r = 0.99, P < 0.001) and lumen volume ( r ...

Background:  Treatment of coronary bifurcation lesions using a single stenting strategy is preferable over that using a 2-stent technique. The benefit of final kissing inflation (FKI), however, has not been established. Methods and Results:  Seventy-two patients (76 lesions) with true bifurcation lesions treated with a single drug-eluting stent with FKI (n=33 lesions) or without FKI (non-FKI, n=43 lesions) were enrolled in this study. Optical coherence tomography (OCT) was performed at 6–12 months after implantation. Based on the OCT findings, the percentage of jailing struts (number of jailing struts/total number of struts at the bifurcation lesion) was ...

Previous intravascular ultrasound studies have shown that echolucent neointimal hyperplasia occasionally appears after bare-metal stent (BMS) or sirolimus-eluting stent (SES) implantation. Optical coherence tomography (OCT) studies have also demonstrated that paclitaxel-eluting stent (PES) restenosis exhibited similar images showing low signal intensity areas (LSIA) surrounding stent struts and three-layer appearance (TLA). The aim of the present study was to investigate the clinical significance of LSIA on OCT images in various types of stents. Fifty nine consecutive patients who underwent scheduled follow-up coronary angiography and OCT were enrolled. There was no significant difference in the prevalence of LSIA among the 3 stent ...

Chronic thromboembolic pulmonary hypertension (CTEPH) is caused by chronic and mechanical obstruction of central and/or distal pulmonary arteries due to thromboembolic masses.1–4 It is one of the distinct disease entities of pulmonary hypertension (PH), with a mean pulmonary arterial pressure >25 mmHg and is classified into the central- and distal-type CTEPH.4–9 As a new therapeutic strategy, percutaneous transluminal pulmonary angioplasty (PTPA) markedly improves pulmonary hemodynamics and long-term prognosis in patients with distal-type CTEPH with no major complications.10 During this procedure, intravascular ultrasound (IVUS) is used to evaluate the presence of chronic thrombus in pulmonary ...

It is now generally recognized that acute coronary syndromes most commonly result from disruption of thin-cap fibroatheroma (TCFA), which is characterized by a large necrotic core with an overlying thin-fibrous cap measuring <65μm. Recent advances in intracoronary imaging modalities have significantly improved the ability to detect TCFA in vivo. Intravascular ultrasound (IVUS) is perhaps the most promising modality that has been used more than 15 years to evaluate atherosclerotic plaque. IVUS has revealed a lot of the clinical evidence regarding vulnerable plaque detection in live humans. Recently, by analyzing the IVUS acoustic signal before demodulation and scan conversion, IVUS ...

Optical coherence tomography-derived anatomical criteria for functionally significant coronary stenosis assessed by fractional flow reserve. The information obtained from a coronary angiogram is essential for determining the treatment strategy of ischemic heart disease. However, the coronary angiogram has some limitations because it is a form of luminology. Therefore, we use a non-invasive stress test in conjunction with angiography before percutaneous coronary intervention (PCI) to determine the significance of the stenosis. To supplement the angiogram, intracoronary imaging techniques, including intravascular ultrasound (IVUS), intracoronary angioscopy, and optical coherence tomography (OCT), have been developed.

We herein report the case of a 66-year-old patient with acute coronary syndrome who was diagnosed with immunoglobulin G4 (IgG4)-related coronary periarteritis with a perivascular pseudotumor and underwent coronary bypass graft surgery (1). The serum IgG4 concentration markedly decreased after the bypass was performed and gradually returned to the baseline level one-year after surgery (2). Despite initially achieving success, the bypass graft to the left circumflex artery (Lcx) was found to be occluded approximately one year post-operation; therefore, we chose to perform percutaneous coronary artery intervention (PCI) in the Lcx. Optical coherence tomography (OCT) images taken immediately before PCI ...

We hypothesized that the tissue components of in-stent restenosis (ISR) might differ between drug-eluting stents (DES) and bare-metal stents (BMS) and that these differences could be distinguished by qualitative and quantitative optical coherence tomography (OCT) analyses. Methods and Results:  One-hundred and twenty-two initial ISR lesions (sirolimus-eluting stents: n=28; paclitaxel-eluting stents: n=51; BMS: n=43) were evaluated with OCT. Based on their OCT appearance, the lesions were classified as homogeneous, layered or heterogeneous. The optical properties of backscatter, attenuation and signal intensity of the neointimal tissue (NIT) were quantified. To evaluate the vascular response after balloon angioplasty (BA), the ...

Optical coherence tomography (OCT) is a high resolution imaging technique that offers microscopic visualization of the coronary artery. The fast scanning speed and simple imaging procedure of new-generation frequency-domain OCT make this technology easy to use in the clinical setting. The OCT examination is useful for guidance and risk stratification of percutaneous coronary intervention (PCI). OCT-derived thin-cap fibroatheroma, which is characterized by large lipid-core and thin fibrous cap <65μm, is a predictor of peri-PCI complications, such as angiographic no-reflow, microvascular obstruction, and post-PCI cardiac troponin I elevation. Stent malapposition, tissue protrusion, and stent edge dissection are assessed in more ...

Background: Cytochrome P450 (CYP) 2C19 polymorphism is associated with reduced responsiveness to clopidogrel and poor clinical outcome after drug-eluting stent (DES) implantation, but its contribution to lesion outcome after DES implantation is unclear. Methods and Results: The study included 160 Japanese patients who received clopidogrel and underwent DES implantation with follow-up angiography. Patients were divided into 3 groups by CYP2C19 polymorphism: extensive metabolizers (EM), intermediate metabolizers (IM), and poor metabolizers (PM). The incidence of major adverse cardiac events (MACE) and target lesion revascularization (TLR) were compared among the 3 groups. Optical coherence tomography (OCT) was performed for 120 patients to ...

60-year-old man was admitted to our hospital due to acute ST-segment elevation myocardial infarction. He had a history of self-expanding stent implantation in the proximal left anterior descending artery due to stable angina pectoris 7 years earlier. Emergent coronary angiography on admission showed occlusion in the distal portion of the previously stented segment, in which observation by optical coherence tomography revealed the existence of a remarkable proliferation of lipid-laden neointimal tissues with rupture and thrombus. This suggests that very late stent thrombosis in a self-expanding stent may occur through the process of atheromatous formation

Background: For the identification of functionally significant coronary artery disease, there have not been any dedicated optical coherence tomography (OCT) studies reported previously, although OCT can clearly detect coronary vessel lumina at higher resolution than intravascular ultrasound (IVUS). Methods and Results: OCT and fractional flow reserve (FFR) measurements were performed in 62 intermediate coronary lesions in 59 patients. FFR was calculated as the ratio of distal coronary pressure divided by proximal coronary pressure during maximal hyperemia. FFR <0.75 was used as the threshold for diagnosing functionally significant stenosis. Minimal lumen area (MLA), minimal lumen diameter (MLD) and percent lumen ...

In this issue of the Journal, a clinical investigation by Ozaki et al focuses on the flushing solution used for image acquisition with frequency-domain optical coherence tomography (FD-OCT). 1 The authors present the cross-sectional area measurement as a quantitative evaluation using low-molecular dextran L (LMD-L) approximate to that of contrast media, and the non-inferiority of LMD-L to contrast media with regard to FD-OCT image quality. Although the cross-sectional and longitudinal images of OCT are analogous with those of intravascular ultrasound (IVUS), the image resolution of OCT is extremely high ( ≈10– 20 μm), which is more than 10-fold that of IVUS ...

We propose the lateral integration scheme of an MEMS tunable VCSEL and a slow light amplifier for increasing single-mode power. The modeling result predicts the maximum output power over several tens mW for a compact slow light amplifier monolithically integrated with an MEMS VCSEL. In addition, the efficient excitation of slow light in the integrated slow light amplifier is shown. A high coupling efficiency and a radiation angle from the amplifier are almost constant during wide wavelength tuning

Although an intracoronary frequency-domain optical coherence tomography (FD-OCT) system overcomes several limitations of the time-domain OCT (TD-OCT) system, the former requires injection of contrast media for image acquisition. The increased total amount of contrast media for FD-OCT image acquisition may lead to the impairment of renal function. The safety and usefulness of the non-occlusion method with low-molecular-weight dextran L (LMD-L) via a guiding catheter for TD-OCT image acquisition have been reported previously. The aim of the present study was to compare the image quality and quantitative measurements between contrast media and LMD-L for FD-OCT image acquisition in coronary stented lesions ...