Hiroyuki Kyono

Consensus standards for acquisition, measurement, and reporting of intravascular optical coherence tomography studies: a report from the International Working Group for Intravascular Optical Coherence Tomography Standardization and Validation.

OBJECTIVES The purpose of this document is to make the output of the International Working Group for Intravascular Optical Coherence Tomography (IWG-IVOCT) Standardization and Validation available to medical and scientific communities, through a peer-reviewed publication, in the interest of improving the diagnosis and treatment of patients with atherosclerosis, including coronary artery disease. BACKGROUND Intravascular optical coherence tomography (IVOCT) is a catheter-based modality that acquires images at a resolution of ~10 μm, enabling visualization of blood vessel wall microstructure in vivo at an unprecedented level of detail. IVOCT devices are now commercially available worldwide, there is an active user base, and the interest in using this technology is growing. Incorporation of IVOCT in research and daily clinical practice can be facilitated by the development of uniform terminology and consensus-based standards on use of the technology, interpretation of the images, and reporting of IVOCT results. METHODS The IWG-IVOCT, comprising more than 260 academic and industry members from Asia, Europe, and the United States, formed in 2008 and convened on the topic of IVOCT standardization through a series of 9 national and international meetings. RESULTS Knowledge and recommendations from this group on key areas within the IVOCT field were assembled to generate this consensus document, authored by the Writing Committee, composed of academicians who have participated in meetings and/or writing of the text. CONCLUSIONS This document may be broadly used as a standard reference regarding the current state of the IVOCT imaging modality, intended for researchers and clinicians who use IVOCT and analyze IVOCT data.

Quantitative optical coherence tomography analysis for late in-stent restenotic lesions.

Coronary optical coherence tomography (OCT) has the potential to identify in-stent neoatherosclerosis, which is a possible risk factor for late acute coronary events after drug-eluting stent implantation. The purpose of this study was to investigate differences between mid-term and late in-stent restenosis after stent implantation by quantitative and semiautomated tissue property analysis using OCT. In total, 1063 OCT image frames of 16 lesions in 15 patients were analyzed. This included 346 frames of 6 lesions in late in-stent restenosis, which was defined as restenosis that was not detected at 6 to 12 months but ≥ 12 months after follow-up coronary angiography. Signal attenuation was circumferentially analyzed using a dedicated semiautomated software. Attenuation was assessed along 200 lines delineated radially for analysis of the in-stent restenotic lesions (between the lumen and stent contours). All lines were anchored by the image wire to avoid artifacts resulting from wire location. Stronger signal attenuation at the frame level (2.46 ± 0.78 versus 1.47 ± 0.32, P < 0.001) and higher maximum signal intensity at the lesion level (9.19 ± 0.19 versus 8.84 ± 0.32, P = 0.018) were observed in late in-stent restenotic lesions than in mid-term in-stent restenotic lesions. OCT demonstrated stronger signal attenuation and higher maximum signal intensity in late in-stent restenotic lesions than in mid-term in-stent restenotic lesions, indicating the possibility of neoatherosclerosis.

Usefulness of Everolimus-Eluting Coronary Stent Implantation in Patients on Maintenance Hemodialysis

The outcomes of second-generation drug-eluting stent (DES) are unknown in patients on maintenance hemodialysis (HD) although HD has been reported as a strong predictor of adverse outcome after the first-generation DES implantation. The OUCH-PRO Study is a prospective multicenter single-arm registry design to study clinical and angiographic outcomes after everolimus-eluting stent (EES). Patients who underwent maintenance HD were prospectively enrolled at the time of elective coronary intervention using EES. Quantitative coronary angiography was performed in an independent core laboratory. The primary end point was the occurrence of target vessel failure (TVF) defined as cardiac death, myocardial infarction (MI), and target vessel revascularization at 1 year. A total of 123 patients were enrolled and 161 EES were implanted. The TVF rate at 1 year was 18% (4% cardiac death, 0% MI, 17% target vessel revascularization). No stent thrombosis was documented. Other clinical events at 1 year were 3% noncardiac death, 3% stroke, and 9% non-target-vessel revascularization. Late lumen loss in stent was 0.37 ± 0.63 mm at 8 months. In conclusion, EES had a high TVF rate and great late lumen loss in patients on HD compared with previous huge EES data in non-HD patients.

Predominant microvessel proliferation in coronary stent restenotic tissue in patients with diabetes: insights from optical coherence tomography image analysis.

BACKGROUND Coronary optical coherence tomography (OCT) enables virtual depiction of histological findings of in-stent restenotic tissue. The aim of this study was to investigate the microvessel proliferation within in-stent restenotic tissue and the influence of diabetes mellitus (DM). METHODS We examined 54 in-stent restenotic coronary artery lesions (stenotic area>50%) from 50 consecutive patients including 28 with DM (56%) and 9 insulin-treated DM patients (18%); who underwent coronary time-domain OCT imaging with automatic pull back (1mm/s, 20 frames/s). Microvessels were defined as low-signal cavities with a diameter of 50-150 microns and a trajectory parallel to the lumen recognized on 3 consecutive cross-sectional OCT image frames. The microvessel index was calculated as the number of frames with microvessel/total number of frames × 100. Patients were stratified into 3 groups: 1) without microvessels, 2) with a low (< median value) microvessel index, 3) with a high microvessel index. RESULTS Microvessels were detected in 566 frames (3.1%) from 26 lesions (48%) in 24 patients (48%). A greater incidence of DM and higher serum glucose levels were observed in the high microvessel index group (DM: 42% vs 58% vs 83%, p=0.049; serum glucose level: 118.2 ± 44.6 vs 122.6 ± 31.0 vs 172.8 ± 63.1mg/dL, p=0.03 between low and high microvessel index group, p=0.005 between no microvessel and high microvessel index group). CONCLUSIONS Microvessel formation may be a unique pathophysiological factor of in-stent restenoses in patients with DM.

Three-Year Clinical and Angiographic Outcomes After Everolimus-Eluting Stent Implantation in Patients With a History of Coronary Artery Bypass Grafting

The clinical and angiographic outcomes after percutaneous coronary intervention (PCI) with everolimus-eluting stent (EES) implantation in patients with a history of coronary artery bypass grafting (CABG) have yet to be fully investigated. The aim of the present study was to investigate 3-year clinical outcomes after EES implantation in patients with a history of CABG.We retrospectively enrolled 176 consecutive patients who had undergone EES implantation. Three-year clinical follow-up data were obtained from all patients. Follow-up angiograms and serial quantitative coronary angiography analysis (QCA) were performed for 139 (79.0%) patients. Patients from the prior CABG (+) group (n = 17; 9.7%) had higher incidences of target lesion revascularization (TLR; 41.2% versus 3.8%, P < 0.001) and major adverse cardiac events (47.1% versus 15.1%, P = 0.004). A landmark analysis conducted 1 year into our study showed a higher incidence of TLR in the prior CABG (+) group (20.0% versus 3.0%, P = 0.017).The reason for EES implantation in the prior CABG (+) group was saphenous vein graft (SVG) failure in 19 (79.2%) lesions, although the target vessel was the SVG in 8 (33.3%) lesions. There were no significant differences in clinical and follow-up QCA data between the native vessel and SVG PCI groups.This study revealed that a history of CABG was a risk factor for TLR after EES implantation. The major reason for PCI after CABG was SVG failure; both native vessel and SVG PCI showed poor outcomes. Further investigations may be warranted to determine which interventions are most effective in this high-risk subset.

Clinical and angiographic outcomes of paclitaxel-eluting coronary stent implantation in hemodialysis patients: A prospective multicenter registry: The OUCH-TL study (outcome in hemodialysis of TAXUS Liberte).

BACKGROUND The outcome of percutaneous coronary intervention (PCI) has been reported to be poor in hemodialysis (HD) patients even in the drug-eluting stent era. We have reported relatively poor outcomes after sirolimus-eluting stent implantation in the OUCH study. METHODS The OUCH-TL study is a prospective, non-randomized, single-arm registry designed to assess the results of paclitaxel-eluting stent (PES) in HD patients with follow-up quantitative coronary angiography analysis. The primary endpoint was the occurrence of target-vessel failure (TVF) defined as cardiac death, myocardial infarction (MI), and target-vessel revascularization (TVR) at 12 months. RESULTS A total of 119 patients with 154 lesions were enrolled (one withdrawal). Mean age was 65±10 years, male gender was 79%, 89% of cases had stable coronary disease. Diabetic nephropathy was diagnosed in 61% of the patients. American College of Cardiology/American Heart Association type B2/C accounted for 96% of lesions and 22.7% of lesions were treated with Rotablator (Boston Scientific Corporation, Natick, MA, USA). Rates of TVF, death, MI, stent thrombosis and TVR at 12 months were 20.2%, 5.9%, 5.0%, 1.4%, and 12.6%, respectively. TVR was performed in 8.4% of the patients up to 12 months. Late loss in-stent was 0.48±0.61mm, and late loss in-segment was 0.37±0.61mm at 9 months. Binary restenosis in-stent was 10.3% and in-segment was 14.5%. CONCLUSIONS Outcomes of PES implantation in hemodialysis patients appears comparable to those of non-hemodialysis patients.

Clinical Characteristics and Long-Term Outcomes of Rotational Atherectomy ― J2T Multicenter Registry ―

BACKGROUND Rotational atherectomy (RA) is an adjunct tool for the management of heavily calcified coronary lesions during percutaneous coronary intervention (PCI), but the long-term clinical outcomes of RA use remain unclear in this drug-eluting stent era.Methods and Results:This multi-center registry assessed the characteristics and outcomes of patients treated by RA for calcified coronary lesions between 2004 and 2015. Among 1,090 registered patients, mean age was 70±10 years and 815 (75%) were male. Sixty percent of patients had diabetes mellitus and 27.7% were receiving hemodialysis. The procedure was successful in 96.2%. In-hospital death occurred in 33 patients (3.0%), and 14 patients (1.3%) developed definite/probable stent thrombosis. During the median follow-up period of 3.8 years, the incidence of major adverse cardiac events (MACE), defined as all-cause death, acute coronary syndrome, stent thrombosis, target vessel revascularization and stroke, was 46.7%. On multivariable Cox hazard analysis, hemodialysis (HR, 2.08; 95% CI: 1.53-2.86; P<0.0001) and age (HR, 1.03; 95% CI: 1.01-1.04; P<0.0001) were strong independent predictors of MACE. Conversely, statin treatment was associated with lower incidence of MACE (P=0.035). CONCLUSIONS This study has provided the largest Japanese dataset for long-term follow-up of RA. Although RA in calcified lesions appears feasible with a high rate of procedural success, a high incidence of MACE was observed.

Incidence, Predictors, and Midterm Clinical Outcomes of Myocardial Injury After Transcatheter Aortic-Valve Implantation

Our aim was to assess the clinical effects of myocardial injury after transcatheter aortic-valve implantation (TAVI). Between October 2013 and July 2016, 157 patients underwent TAVI with Sapien XT, Sapien 3, or CoreValve prostheses at our institute. Of these, 130 patients for whom the transapical approach was not used were included in this study. Myocardial injury was defined as a peak troponin I level of ≥1.5 ng/mL within 48 hours after TAVI. We evaluated the predictors of myocardial injury and compared the clinical outcomes of 82 patients classified as the myocardial injury group and 44 patients classified as the non-myocardial injury group. The patients were aged 85 ± 6 years. Myocardial injury occurred in 82 patients (65.1%). Age (per 1 increase) (odds ratio [OR]: 1.11, 95% confidence interval [CI]: 1.01-1.22, P = 0.041), female sex (OR: 3.88, 95% CI: 1.23-12.22, P = 0.021), valve type (Sapien XT; OR: 4.22, 95% CI: 1.15-15.47, P = 0.03, Core valve; OR: 18.12, 95% CI: 2.86-114.59, P = 0.002), balloon aortic valvuloplasty as a bridge therapy (OR: 0.10, 95% CI: 0.02-0.42, P = 0.002), and left ventricular end-diastolic volume (LVEDV) (per 1 increase) (OR: 0.97, 95% CI: 0.95-0.99, P = 0.003) were associated with myocardial injury in a multivariate model. The myocardial injury group did not have a higher rate of midterm (365-day) mortality (log-rank test P = 0.57) than the non-myocardial injury group on Kaplan-Meier analysis. Myocardial injury after TAVI was not associated with midterm mortality.

Serial Quantitative Coronary Analyses for the Evaluation of One-Year Change in Saphenous Vein Grafts

BACKGROUND A paucity of data exists with respect to changes in whole saphenous vein grafts (SVGs) despite accelerated atherosclerosis within grafted saphenous vein conduits. In the present study, we evaluated the one-year change in SVGs by means of quantitative coronary analysis. METHODS This study enrolled consecutive 52 patients with 109 SVGs, who underwent coronary artery bypass graft surgery successfully. A follow-up study was performed in 33 patients with 65 SVGs after one year because 16 SVGs were obstructed (baseline, 8; follow-up period, 8), and 15 patients with 28 SVGs dropped out within one year. RESULTS Both minimal and mean lumen diameters decreased significantly (3.17 +/- 0.64 mm vs 2.41 +/- 0.57 mm, p < 0.001; 3.70 +/- 0.69 mm vs 2.92 +/- 0.70 mm, p < 0.001; respectively). Graft length also decreased significantly (107.1 +/- 25.8 vs 100.6 +/- 25.2 mm, p < 0.001). The graft shortening rate (graft shortening length/baseline graft length x 100) was greater than 5% in 33 vessels (51%) and greater than 10% in 23 vessels (35%). Coronary risk factors (smoking, diabetes mellitus, hypertension, dyslipidemia) did not reveal significant relationship with late loss of minimal and mean lumen diameters. CONCLUSIONS The present study showed a considerable and uniform lumen loss of SVGs after one year, irrespective of coronary risk factors. Graft length shortening was seen more than elongation.