Optical coherence tomography in coronary atherosclerosis assessment and intervention.

Since optical coherence tomography (OCT) was first performed in humans two decades ago, this imaging modality has been widely adopted in research on coronary atherosclerosis and adopted clinically for the optimization of percutaneous coronary intervention. In the past 10 years, substantial advances have been made in the understanding of in vivo vascular biology using OCT. Identification by OCT of culprit plaque pathology could potentially lead to a major shift in the management of patients with acute coronary syndromes. Detection by OCT of healed coronary plaque has been important in our understanding of the mechanisms involved in plaque destabilization and healing with the rapid progression of atherosclerosis. Accurate detection by OCT of sequelae from percutaneous coronary interventions that might be missed by angiography could improve clinical outcomes. In addition, OCT has become an essential diagnostic modality for myocardial infarction with non-obstructive coronary arteries. Insight into neoatherosclerosis from OCT could improve our understanding of the mechanisms of very late stent thrombosis. The appropriate use of OCT depends on accurate interpretation and understanding of the clinical significance of OCT findings. In this Review, we summarize the state of the art in cardiac OCT and facilitate the uniform use of this modality in coronary atherosclerosis. Contributions have been made by clinicians and investigators worldwide with extensive experience in OCT, with the aim that this document will serve as a standard reference for future research and clinical application.

Primary Percutaneous Coronary Intervention in Elderly Patients With Acute Myocardial Infarction　- An Analysis From a Japanese Nationwide Claim-Based Database.

BACKGROUND: Primary percutaneous coronary intervention (pPCI) is strongly recommended by guidelines for patients presenting with acute myocardial infarction (AMI), but its applications in elderly patients are less clear.Methods and Results:The JROAD-DPC is a Japanese nationwide registry for patients with cardiovascular diseases combined with an administrative claim-based database. Among 2,369,165 records from 2012 to 2015, data for 115,407 AMI patients were extracted for this study. Elderly patients (≥75 years) comprised 45,645 subjects (39.6%), and received pPCI less frequently (62.2%) than younger patients (79.2%, P<0.001). Clinical variables such as higher age, female sex, higher Killip class, and renal dysfunction, but not functional status on admission, were predictors of non-application of pPCI. Endpoint 30-day mortality increased with aging, and was significantly higher in elderly patients (10.7%) than in younger patients (3.8%, P<0.001). Indeed, pPCI was independently associated with lower 30-day mortality only in subgroups of patients aged ≥60 years. Propensity score-matching analysis confirmed a similar reduction in endpoint 30-day mortality with pPCI in elderly patients. Duration of hospitalization was significantly shorter and functional ability on discharge was significantly better in elderly patients who underwent pPCI. CONCLUSIONS: Elderly patients with AMI underwent pPCI less frequently, but it was consistently associated with better clinical outcome in these patients. Our findings support the proactive application of pPCI for elderly AMI patients when they are eligible for an invasive strategy.

Impact of Institutional and Operator Volume on Short-Term Outcomes of Percutaneous Coronary Intervention: A Report From the Japanese Nationwide Registry.

OBJECTIVES: The aim of this study was to assess the volume-outcome relationship for PCI within the nationwide registration system in Japan. BACKGROUND: The effect of site and operator case load for percutaneous coronary intervention (PCI) on outcomes has not been investigated thoroughly in non-Western regions. METHODS: In the present study, PCI procedural data recorded between January 2014 and December 2015 in the Japanese PCI registry, a nationwide registration system, were analyzed. Institutions and operators were categorized into deciles based on the number of PCIs performed per year. Odds ratios (ORs) for in-hospital mortality and the composite endpoint (in-hospital death and periprocedural complications) were estimated for each decile (with the lowest volume group as a reference group). RESULTS: A total of 323,322 PCIs (at 625 hospitals [median PCI cases/year: 216; quartiles: 121 to 332] by 4,211 operators [median PCI cases/year: 28; quartiles: 10 to 56]) were analyzed, of which 2,959 patients (0.9%) and 7,205 patients (2.2%) experienced in-hospital mortality and the composite endpoint after PCI, respectively. The adjusted risk for in-hospital mortality and the composite endpoint was significantly higher in hospitals included in the lowest decile (<150 PCIs/year); the risk remained consistently low across the remaining deciles. Contrastingly, no significant volume-outcome relationship was observed between operator volume and outcomes. A similar trend was observed when the analysis was confined to emergency/urgent PCI cases. CONCLUSIONS: In contemporary Japanese PCI practice, lower institutional volume was related inversely to in-hospital outcomes, but the association of annual operator volume with outcomes was less clear.

In vivo assessment of vasa vasorum neovascularization using intravascular ultrasound: A comparison between acute coronary syndrome and stable angina pectoris.

BACKGROUND: Previous studies have suggested that vasa vasorum (VV) neovascularization plays an important role in the progression and vulnerability of coronary atherosclerotic plaque. METHODS: A total of 130 patients with coronary artery disease including 75 acute coronary syndrome (ACS) cases and 55 stable angina pectoris (SAP) cases were studied. By using intravascular ultrasound (IVUS), VV was defined as a small (<1mm) tubular or vesicular, low-echoic structure observed exterior to the media. Prevalence and maximal number of VV were compared between patients with ACS versus SAP. RESULTS: The prevalence of VV at the culprit lesion was similar between the 2 groups (97% vs. 93%, p=0.216). On the other hand, it was significantly higher in ACS than SAP at both reference sites (proximal: 93% vs. 81%, p=0.047 and distal: 88% vs. 60%, p<0.001, respectively). The maximum number of VV was significantly higher in ACS than in SAP (at the culprit lesion: 2.8±1.3 vs. 1.8±1.0, p<0.001, at the proximal reference: 1.9±1.1 vs. 1.3±0.9, p=0.003 and distal reference: 1.7±1.1 vs. 1.1±1.1, p=0.003, respectively). CONCLUSIONS: VV neovascularization of coronary arteries was more enhanced in patients with ACS than in those with SAP, supporting its relation to plaque vulnerability. VV detected by widely used IVUS could be an adequate surrogate marker for plaque vulnerability in vivo.

Assessment of Coronary Plaque Vulnerability with Optical Coherence Tomography.

UNLABELLED: Several catheter-based imaging modalities have been developed over the past 2 decades for visualizing the morphological features of coronary atherosclerotic plaques that are susceptible to future development of serious cardiovascular events. Optical coherence tomography (OCT) is a new high-resolution intracoronary imaging modality based on near-infrared interferometry, and it has been shown to be able to identify various components of atheromatous plaques. In this review, we examine the histopathology of vulnerable plaques as a target for imaging technology, and discuss the evidence of OCT in identifying vulnerable atherosclerotic lesions in patients with coronary artery disease. KEY WORDS: Coronary artery disease; Optical coherence tomography; Vulnerable plaque.

OCT compared with IVUS in a coronary lesion assessment: the OPUS-CLASS study.

OBJECTIVES: The aim of this study was to investigate the reliability of frequency domain optical coherence tomography (FD-OCT) for coronary measurements compared with quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS). BACKGROUND: Accurate luminal measurement is expected in FD-OCT because this technology offers high resolution and excellent contrast between lumen and vessel wall. METHODS: In 5 medical centers, 100 patients with coronary artery disease were prospectively studied by using angiography, FD-OCT, and IVUS. In addition, 5 phantom models of known lumen dimensions (lumen diameter 3.08 mm; lumen area 7.45 mm(2)) were examined using FD-OCT and IVUS. Quantitative image analyses of the coronary arteries and phantom models were performed by an independent core laboratory. RESULTS: In the clinical study, the mean minimum lumen diameter measured by QCA was significantly smaller than that measured by FD-OCT (1.81 ± 0.72 mm vs. 1.91 ± 0.69 mm; p < 0.001) and the minimum lumen diameter measured by IVUS was significantly greater than that measured by FD-OCT (2.09 ± 0.60 mm vs. 1.91 ± 0.69 mm; p < 0.001). The minimum lumen area measured by IVUS was significantly greater than that by FD-OCT (3.68 ± 2.06 mm(2) vs. 3.27 ± 2.22 mm(2); p < 0.001), although a significant correlation was observed between the 2 imaging techniques (r = 0.95, p < 0.001; mean difference 0.41 mm(2)). Both FD-OCT and IVUS exhibited good interobserver reproducibility, but the root-mean-squared deviation between measurements was approximately twice as high for the IVUS measurements compared with the FD-OCT measurements (0.32 mm(2) vs. 0.16 mm(2)). In a phantom model, the mean lumen area according to FD-OCT was equal to the actual lumen area of the phantom model, with low SD; IVUS overestimated the lumen area and was less reproducible than FD-OCT (8.03 ± 0.58 mm(2) vs. 7.45 ± 0.17 mm(2); p < 0.001). CONCLUSIONS: The results of this prospective multicenter study demonstrate that FD-OCT provides accurate and reproducible quantitative measurements of coronary dimensions in the clinical setting.

Morphological features of coronary arteries in patients with coronary spastic angina: assessment with intracoronary optical coherence tomography.

BACKGROUND: Coronary spasm (CS) plays an important role in the pathogenesis of many types of ischemic heart disease, but morphological appearance of non-stenotic coronary segments with CS is not fully understood. We evaluate the morphological characteristics of coronary arteries in patients with coronary spastic angina (CSA) using intravascular optical coherence tomography (OCT). METHODS: We evaluated 37 patients with resting chest pain whose coronary angiograms did not reveal significant stenosis. These patients underwent an acetylcholine (ACh) provocation test. OCT was performed after complete dilatation of coronary arteries, and additionally during ACh-induced CS in four patients. RESULTS: Based on the ACh test, 23 patients were diagnosed as having CSA, and the remaining 14 patients without CS were referred to as CS-negative. OCT study revealed that coronary segments with ACh-induced CS had homogeneous intimal thickening, and quantitative analysis showed that CS-positive segments had a significantly greater intima area as compared with corresponding CS-negative segments without lipid or calcium content. By contrast, CS-positive segments had a significantly smaller intima area as compared with CS-negative segments with lipid or calcium deposit. During ACh-induced CS, lumen and total vascular areas were significantly decreased, whereas intima area did not change in comparison with complete vasodilatation. The luminal surface of the intima formed a markedly wavy configuration during CS. CONCLUSIONS: Coronary artery segments involved in CS are characterized by diffuse intimal thickening without lipid or calcium content. High-resolution coronary OCT imaging could make it possible to analyze the vascular pathophysiology in patients with CS.

Novel application of black-blood echo-planar imaging to the assessment of myocardial infarction.

The purpose of this study was to clarify the characteristics of black-blood echo-planar imaging (BB-EPI) in the assessment of infarct-related myocardial edema (IRME), compared with T2-weighted imaging (T2WI). Thirteen acute myocardial infarction (MI) patients after reperfusion and 11 old MI patients underwent BB-EPI and T2WI, excluding those with posterior MI. In acute MI patients, signal intensity ratio (SI ratio) of edema to normal myocardium was measured. Black-blood echo-planar imaging revealed hyperintensity in the same region identified as IRME on T2WI in all acute MI patients, and SI ratio was significantly higher in BB-EPI (2.66 +/- 1.58) than in T2WI (1.44 +/- 0.22) (P < 0.05). However, BB-EPI showed hyperintensity in posterior wall, where there is no clinical evidence of acute MI, in 2 out of 13 acute MI patients. Both T2WI and BB-EPI detected no IRME in known old infarct area of all old MI patients, but BB-EPI showed hyperintensity in the posterior wall of 4 out of 11 old MI patients. Black-blood echo-planar imaging can depict IRME with sufficient suppression of background and blood flow signals, and with excellent edema-to-normal myocardium contrast resolution. However, BB-EPI sometimes shows an inconsistent signal area with T2WI specifically in posterior wall. The wide practical use of BB-EPI requires the solution to this serious problem.

[Assessment of coronary artery by four-detector multislice computed tomography: diagnostic accuracy and limitations for coronary artery lesions].

OBJECTIVES: The applicability of four-detector multislice computed tomography (MSCT) was investigated for evaluating coronary arteries. METHODS: MSCT (Somatom Volume Zoom, Siemens) was used to evaluate the coronary arteries in 94 patients. The reconstructed images were analyzed using retrospective electrocardiographic gating to determine the image quality of the coronary arteries. In addition, the ability of MSCT to detect coronary artery lesions of > or = 70% (> or = 50% in the left main trunk) diameter stenoses documented by standard coronary angiography was assessed in 67 patients who underwent coronary angiography within the same period. RESULTS: Good image quality was displayed in 488 (58%) and fair in 184 (22%) of a total of 846 coronary segments, but non-assessable in 174 (21%) due to degraded image quality. MDCT detected 33 stenotic lesions correctly in 494 assessable segments, comparable to coronary angiography. The sensitivity and specificity of MSCT were 0.79 and 0.95, respectively. However, an additional 15 lesions were detected by coronary angiography among the non-assessable segments. In total, 24 lesions were missed by MSCT. Accordingly, coronary segments were completely assessable and correctly detected by MSCT in only 20 patients (30%), or 35 (52%) if the distal coronary segments were excluded from analysis. CONCLUSIONS: Four-detector MSCT for detection of coronary artery lesions was applicable to assessable segments. However, clinical use may presently be limited because of the insufficient overall accuracy. Further technical improvement is expected in the near future.