The prognostic value of mean platelet volume in patients with coronary artery disease: An updated systematic review with meta-analyses.

BACKGROUND: Mean platelet volume (MPV) is a widely available laboratory index, however its prognostic significance in patients with coronary artery disease (CAD) is still unclear. We intended to investigate and pool the evidence on the prognostic utility of admission MPV in predicting clinical outcomes in patients with CAD. METHODS: PubMed, Web of Science, and Scopus were the major databases used for literature search. The risk of bias was assessed using the quality in prognostic factor studies. We used random-effects pairwise analysis with the Knapp and Hartung approach supported further with permutation tests and prediction intervals (PIs). RESULTS: We identified 52 studies with 47,066 patients. A meta-analysis of nine studies with 14,864 patients demonstrated that one femtoliter increase in MPV values was associated with a rise of 29% in the risk of long-term mortality (hazard ratio [HR] 1.29, 95% confidence interval [CI] 1.22-1.37) in CAD as a whole. The results were further supported with PIs, permutation tests and leave-one-out sensitivity analyses. MPV also demonstrated its stable and significant prognostic utility in predicting long-term mortality as a linear variable in patients treated with percutaneous coronary intervention (PCI) and presented with acute coronary syndrome (ACS) (HR 1.29, 95% CI 1.20-1.39, and 1.29, 95% CI 1.19-1.39, respectively). CONCLUSION: The meta-analysis found robust evidence on the link between admission MPV and the increased risk of long-term mortality in patients with CAD patients, as well as in patients who underwent PCI and patients presented with ACS.

The effects of catheter ablation of outflow tract premature ventricular complexes on atrial electromechanical delay.

BACKGROUND: Consistent data from several studies have shown that catheter ablation of frequent premature ventricular complexes (PVCs) results in substantial improvement in left ventricular ejection fraction (LVEF), left ventricular diastolic function, and left atrial volume and mechanics. However, the effects of catheter ablation of PVCs on atrial electromechanical properties have not been documented yet. AIMS: In the present study, we investigated the short-term effects of radiofrequency catheter ablation (RFCA) of outflow tract PVCs on atrial electromechanical delay (EMD). METHODS: A total of 71 subjects with idiopathic outflow tract PVCs who underwent RFCA were included. Interatrial and intra-atrial EMDs were measured by tissue Doppler imaging before and 3 months after catheter ablation. RESULTS: The study population was divided into normal ejection fraction (EF) and low-EF subgroups according to their LVEF. In all study groups, substantial improvement was found in lateral electromechanical coupling time (PA), septal PA, right ventricular PA, interatrial EMD, left-sided intra-atrial EMD, and right-sided intra-atrial EMD. No treatment heterogeneity was observed when comparing low-EF and normal-EF subgroups with respect to atrial EMDs (interatrial EMD, interaction p = .29; left-sided intra-atrial EMD, interaction p = .13; right-sided intra-atrial EMD, interaction p = .88). CONCLUSION: RFCA of outflow tract PVC has a favorable early effect on intra- and inter-atrial EMDs irrespective of preprocedural LVEF.

Effect of the number of parity on right heart chamber quantification.

INTRODUCTION: Pregnancy is a process that can cause several physiologic changes to the cardiovascular system such as ventricular hypertrophy and dilation of cardiac chambers. Although there are studies about pregnancy-related changes in echocardiographic examination; there is no data about the long-term effects of parity on these alterations. Therefore, we evaluated the long-term effect of pregnancy on right ventricular (RV) dilation and RV hypertrophy and their relation to the parity number. METHODS: This prospective study included a total of 600 women (200 consecutive women who had no parity, 200 women who had a parity number of 1 to 4 and 200 women who had a parity number of more than 4). Right chambers' measurements were compared between the groups. RESULTS: In echocardiographic analysis, RV and right atrial dimensions and areas and RV wall thickness were higher in parous women. On the other hand, RV systolic function parameters were significantly lower in parous women. These significant changes showed a gradual increase or decrease by increasing parity number. By multivariate hierarchical logistic regression analysis, the four independent factors that increased the risk of RV dilation were age (OR: 1.16 CI: 1.10-1.20), body mass index (OR: 1.05, CI: 1.02-1.08), smoking (OR: 1.87, CI: 1.28-4.02), and giving a birth (OR: 3.94 CI: 1.82-8.81). There was also independent relationship between the number of parity and RV hypertrophy even after adjustment for several confounders. CONCLUSION: Pregnancy-related physiological changes mostly resolve after delivery. This study about long-term effects of pregnancy on RV has demonstrated that there is a significant relation between the number of parity and either RV dilation or RV hypertrophy. Each parity had also additive effect on these changes.

The relationship between hemoglobin A1c levels and thrombus load in patients with type 2 diabetes mellitus and non-ST-segment elevation myocardial infarction.

BACKGROUND: We aimed to investigate the relationship between hemoglobin A1c (HbA1c) and coronary thrombus load in type-2 diabetes mellitus (T2DM) patients with non-ST segment elevation myocardial infarction (NSTEMI). MATERIALS AND METHODS: Ninety diabetic patients with NSTEMI were recruited for the study. They were separated into two groups according to HbA1c levels. Forty-seven patients having HbA1c ≤6.5% formed Group-I (35 male, mean age 58 ± 10.5 years) and the remaining 43 patients with HbA1c >6.5% formed Group-II (23 male, mean age 58 ± 11.1 years). Both the groups were evaluated in terms of thrombolysis in myocardial infarction (TIMI) thrombus score and Syntax score. RESULTS: Baseline patient characteristics were comparable in both the groups. TIMI thrombus score and Syntax score were higher in Group II than in Group I (3.2 ± 1.4 vs. 4.7 ± 0.5 and 20.2 ± 3.4 vs. 26.3 ± 3.0 respectively, P < 0.05). No significant difference was found in other parameters. In stepwise linear regression analysis, prepercutaneous coronary intervention (PCI) and post-PCI TIMI frame number and HbA1c were significantly related to the coronary thrombus scale. However, no significant relationship has been found between thrombus formation and hypertension, previous PCI history, pre-PCI heart rate, pre-PCI cholesterol status, and high-sensitive troponin T. CONCLUSION: In NSTEMI with T2DM, increased HbA1c (HbA1c >6.5%) is related with coronary thrombus in the target vessel. In those patient population, strict anticoagulation should be considered to prevent potential adverse events.

The role of oxidative stress on subclinical atherosclerosis in premature ovarian insufficiency and relationship with carotid intima-media thickness.

Objective: We aimed to investigate the relationship between oxidative stress (OS) and subclinical atherosclerosis in patients with premature ovarian insufficiency (POI), by analyzing the dynamic thiol/disulfide homeostasis (TDH) parameters as an OS marker and carotid intima-media thickness (CIMT).Materials and methods: A total of 69 women, 34 with POI and 35 healthy controls were included in this prospective cross-sectional study. TDH parameters (plasma native thiol, total thiol, disulfide, disulfide/native thiol, native thiol/total thiol, and disulfide/total thiol ratios) and CIMT were measured and compared between the two groups.Results: In primary ovarian insufficiency group, native thiol (p=.009) and total thiol (p=.010) levels were significantly decreased, and CIMT values were significantly increased (p= <.001). CIMT values were negatively correlated with native thiol (r=-0.553, p=.001) and total thiol levels (r=-0.565, p=.001); and positively correlated with age (r = 0.457, p=.007), BMI (r = 0.408, p=.017), and total cholesterol (r = 0.605, p<.001) in POI group.Conclusions: Decreased native thiol and total thiol levels demonstrate the defective anti-oxidant mechanism in POI. Negative correlation between native thiol, total thiol levels, and CIMT means the presence of abnormal anti-oxidant mechanisms may play a role in the development of subclinical atherosclerosis in patients with POI. This is a novel report on the mechanism of subclinical atherosclerosis in women with POI, which needs to be supported with further studies evaluating the pathophysiology of OS.

Bioresorbable Scaffold: The Emerging Reality and Future Directions.

In the era of drug-eluting stents, large-scale randomized trials and all-comer registries have shown excellent clinical results. However, even the latest-generation drug-eluting stent has not managed to address all the limitations of permanent metallic coronary stents, such as the risks of target lesion revascularization, neoatherosclerosis, preclusion of late lumen enlargement, and the lack of reactive vasomotion. Furthermore, the risk of very late stent, although substantially reduced with newer-generation drug-eluting stent, still remains. These problems were anticipated to be solved with the advent of fully biodegradable devices. Fully bioresorbable coronary scaffolds have been designed to function transiently to prevent acute recoil, but have retained the capability to inhibit neointimal proliferation by eluting immunosuppressive drugs. Nevertheless, long-term follow-up data of the leading bioresorbable scaffold (Absorb) are becoming available and have raised a concern about the relatively higher incidence of scaffold thrombosis. To reduce the rate of clinical events, improvements in the device, as well as implantation procedure, are being evaluated. This review will focus on the current CE-mark approved bioresorbable scaffolds, their basic characteristics, and clinical results. In addition, we summarize the current limitations of bioresorbable scaffold and their possible solutions.

Serial Optical Coherence Tomography at Baseline, 7 Days, and 1, 3, 6 and 12 Months After Bioresorbable Scaffold Implantation in a Growing Porcine Model.

BACKGROUND: Little is known about serial changes in lumen and device dimensions after bioresorbable scaffold implantation in a growing animal model. Methods and Results: ABSORB (n=14) or bare metal stents (ICROS amg [Abbott Vascular, Santa Clara, CA, USA], Winsen-Luhe, Germany; n=15) were implanted in the coronary arteries of domestic swine (a hybrid of Finnish-Norwegian Landrace swine) weighing 30-35 kg. Angiography and optical coherence tomography (OCT) were performed immediately after implantation and repeated at 7 days, 1, 3, 6 and 12 months after the index procedure. One month after implantation, mean lumen area decreased relative to baseline in both groups (relative area change from baseline, -41.4±15.6% for ABSORB vs. -20.9±18.6% for ICROS) while mean device area decreased only in the ABSORB group (relative area change: -11.1±9.4% vs. +0.14±7.95%, respectively). At 12 months, mean lumen area increased relative to baseline in both groups (relative area change from baseline, +55.6±22.4% vs. +32.3±83.6%, respectively) in accordance with the swine growth weighing up to 260-300 kg. Mean device area in the ICROS group remained stable whereas that in the ABSORB group began to increase between 3 and 6 months along with the vessel growth (relative area change: +107.8±25.7% vs. +0.14±7.95%). CONCLUSIONS: In the growing porcine model, ABSORB was associated with greater extent of recoil 1 month after implantation compared with ICROS but demonstrated substantial adaptability to vessel growth in late phase.

Successful cryoablation of atrial fibrillation from jugular approach in patient with interrupted inferior vena cava and azygos continuation.

We herein report successful cryoablation of paroxysmal atrial fibrillation via right jugular vein in a patient with interrupted inferior vena cava. We preferred cryoablation instead of radiofrequency ablation in the treatment of our patient. For stronger support in aiming the Brockenbrough needle toward the septum, we manuallly curved the needle with a 120° angle about 6 cm proximal to the tip. After successful transseptal puncture, we performed balloon dilatation in the septal puncture zone to facilitate passage. Cryoablation has theoretical advantage, particularly in challenging anatomies, in which it eliminates the need for point-by-point ablation around the pulmonary vein.

Increased exercise-related platelet activation assessed by impedance aggregometry in diabetic patients despite aspirin therapy.

Aspirin is widely used for the prevention of thromboembolic diseases, but inhibition of platelet aggregation (PA) is not uniform. Additionally, aspirin has been shown to be ineffective in blunting PA in response to exercise in patients with coronary artery disease (CAD). Limited data exists about platelet function following acute exercise in diabetics taking aspirin. In our study, we aimed to investigate PA before and after exercise stress test in type-2 diabetic patients taking aspirin. Forty-three patients with type-2 diabetes mellitus (DM) and 36 subjects (age- and sex-matched) as control group were included prospectively. All participants were under aspirin (100 mg/day) therapy for at least 1 week. The measures of PA were assessed by impedance aggregometry using arachidonic acid as an agonist (ASPI test). Blood samplings were undertaken before and immediately after treadmill exercise test. At rest, diabetic and control groups had comparable pre-exercise PA (22.97 ± 14.57 versus 22.11 ± 12.71 AU min, p = NS, respectively). After treadmill exercise, both groups showed significantly higher absolute increase (9.02 ± 13.08 and 3.66 ± 5.87 AU min, p < 0.01, p < 0.01, respectively) and percent (%) increase (45.67 ± 49.34 and 24.04 ± 46.59 AU min, p < 0.01, p = 0.01, respectively) in PA. Both absolute increase (p < 0.05) and % increase (p < 0.05) in PA were significantly higher in DM group compared to the control group. Multiple regression analysis revealed that high-sensitive C-reactive protein (p = 0.014) was independent predictor of absolute increase PA. Our study showed that aspirin has limited effect in inhibiting exercise-induced PA, even in the absence of documented CAD. The increase in PA following exercise was significantly greater in patients with DM compared with controls.

Angiographic late lumen loss revisited: impact on long-term target lesion revascularization.

Aim: In current device trials, the values of angiographic late lumen loss (LLL) have become extremely low and the relationship between LLL and clinical endpoints has not been recently re-evaluated. The impact of LLL on target lesion revascularization (TLR) in a patient- and study-level analysis of contemporary coronary devices was investigated. Methods and results: We performed a patient-level meta-analysis of seven randomized controlled trials including 2426 patients treated with first- and second-generation drug-eluting stents (DES) and a study-level meta-analysis of 40 studies including 19 199 patients treated with CE-marked DES. In the patient-level analysis, the probability regression curve showed an exponential relationship between in-stent LLL and 2-year incidence of TLR. The optimal cut-off value of LLL based on Youden's index for 2-year TLR event was 0.50 mm. In the Cox proportional hazard model, LLL >0.50 mm was independently associated with an increased incidence of TLR up to 4 years after angiographic follow-up {adjusted hazard ratio (HR) 6.62 [95% confidence interval (95% CI) 4.67-9.39], P < 0.001}. In the meta-regression analysis of the DES studies, pooled mean value of LLL was as low as 0.23 mm (95% CI 0.20-0.26), and there was a moderate correlation between the 1- and 5-year incidence of TLR and the percentage of the lesions with LLL >0.50 mm (R2 = 0.44, P < 0.001 at 1 year, R2 = 0.40, P < 0.001 at 5 years). Conclusion: An angiographic LLL ≤0.50 mm was not predictive of the incidence of TLR whereas a LLL >0.50 mm was. Low LLL in contemporary device trials may not be a sufficiently discriminating parameter for the comparative evaluation of devices.

Endothelial shear stress 5 years after implantation of a coronary bioresorbable scaffold.

Aims: As a sine qua non for arterial wall physiology, local hemodynamic forces such as endothelial shear stress (ESS) may influence long-term vessel changes as bioabsorbable scaffolds dissolve. The aim of this study was to perform serial computational fluid dynamic (CFD) simulations to examine immediate and long-term haemodynamic and vascular changes following bioresorbable scaffold placement. Methods and results: Coronary arterial models with long-term serial assessment (baseline and 5 years) were reconstructed through fusion of intravascular optical coherence tomography and angiography. Pulsatile non-Newtonian CFD simulations were performed to calculate the ESS and relative blood viscosity. Time-averaged, systolic, and diastolic results were compared between follow-ups. Seven patients (seven lesions) were included in this analysis. A marked heterogeneity in ESS and localised regions of high blood viscosity were observed post-implantation. Percent vessel area exposed to low averaged ESS (<1 Pa) significantly decreased over 5 years (15.92% vs. 4.99%, P < 0.0001) whereas moderate (1-7 Pa) and high ESS (>7 Pa) did not significantly change (moderate ESS: 76.93% vs. 80.7%, P = 0.546; high ESS: 7.15% vs. 14.31%, P = 0.281), leading to higher ESS at follow-up. A positive correlation was observed between baseline ESS and change in lumen area at 5 years (P < 0.0001). Maximum blood viscosity significantly decreased over 5 years (4.30 ± 1.54 vs. 3.21± 0.57, P = 0.028). Conclusion: Immediately after scaffold implantation, coronary arteries demonstrate an alternans of extremely low and high ESS values and localized areas of high blood viscosity. These initial local haemodynamic disturbances may trigger fibrin deposition and thrombosis. Also, low ESS can promote neointimal hyperplasia, but may also contribute to appropriate scaffold healing with normalisation of ESS and reduction in peak blood viscosity by 5 years.

Diagnostic performance of angiography-derived fractional flow reserve: a systematic review and Bayesian meta-analysis.

Aims: Pressure-wire assessment of coronary stenosis is considered the invasive reference standard for detection of ischaemia-generating lesions. Recently, methods to estimate the fractional flow reserve (FFR) from conventional angiography without the use of a pressure wire have been developed, and were shown to have an excellent diagnostic accuracy. The present systematic review and meta-analysis aimed at determining the diagnostic performance of angiography-derived FFR for the diagnosis of haemodynamically significant coronary artery disease. Methods and results: A systematic review and meta-analysis of studies assessing the diagnostic performance of angiography-derived FFR systems were performed. The primary outcome of interest was pooled sensitivity and specificity. Thirteen studies comprising 1842 vessels were included in the final analysis. A Bayesian bivariate meta-analysis yielded a pooled sensitivity of 89% (95% credible interval 83-94%), specificity of 90% (95% credible interval 88-92%), positive likelihood ratio (+LR) of 9.3 (95% credible interval 7.3-11.7) and negative likelihood ratio (-LR) of 0.13 (95% credible interval 0.07-0.2). The summary area under the receiver-operating curve was 0.84 (95% credible interval 0.66-0.94). Meta-regression analysis did not find differences between the methods for pressure-drop calculation (computational fluid dynamics vs. mathematical formula), type of analysis (on-line vs. off-line) or software packages. Conclusion: The accuracy of angiography-derived FFR was good to detect haemodynamically significant lesions with pressure-wire measured FFR as a reference. Computational approaches and software packages did not influence the diagnostic accuracy of angiography-derived FFR. A diagnostic strategy trial with angiography-derived FFR evaluating clinical endpoints is warranted.

Left Atrial Function Is Improved in Short-Term Follow-Up after Catheter Ablation of Outflow Tract Premature Ventricular Complexes.

Background: Association of premature ventricular complexes (PVC) with left ventricular systolic dysfunction (LVSD) and efficacy of catheter ablation treatment have been demonstrated in studies. The role of left atrial (LA) mechanics in the etiopathogenesis of PVC-induced cardiomyopathy (PVC-CMP) as well as changes in LA mechanics with catheter ablation have not been studied before. Methods: A total number of 61 patients (Mean Age 43 ± 3) with idiopathic outflow tract (OT) PVCs undergoing radiofrequency catheter ablation (RFCA) were enrolled. ECG, 24 h Holter, and echocardiographic evaluation with left ventricular (LV) diastolic functions and LA volumetric assessments were performed before and three months after RFCA. Results: Along with a marginal increase in left ventricle ejection fraction (LVEF), improvement in diastolic functions and left atrial mechanics were observed in the study (LVEF 53 ± 7 versus 57 ± 6, p < 0.01) in short-term follow-up. The frequency of LV diastolic dysfunction (LVDD) decreased with catheter ablation (n = 5 to 0, p = 0.02). The overall LA function improved. Left atrium passive and overall emptying fraction (LAEF) increased significantly (0.32 ± 0.04 to 0.41 ± 0.04, p < 0.05 and 0.62 ± 0.04 to 0.65 ± 0.004, p < 0.05, respectively). Active LAEF decreased significantly (0.29 ± 0.005 to 0.24 ± 0.006, p < 0.05). Conclusions: The results of this study are indicative of "PVC-induced atriomyopathy" which responds to RFCA in short-term follow-up. Atrial dysfunction might play a role in symptoms and etiopathogenesis of LVSD.

Hemodynamic analysis of a novel bioresorbable scaffold in porcine coronary artery model.

BACKGROUND: The shear stress distribution assessment can provide useful insights for the hemodynamic performance of the implanted stent/scaffold. Our aim was to investigate the effect of a novel bioresorbable scaffold, Mirage on local hemodynamics in animal models. METHOD: The main epicardial coronary arteries of 7 healthy mini-pigs were implanted with 11 Mirage Microfiber sirolimus-eluting Bioresorbable Scaffolds (MMSES). Optical coherence tomography (OCT) was performed post scaffold implantation and the obtained images were fused with angiographic data to reconstruct the coronary artery anatomy. Blood flow simulation was performed and Endothelial Shear Stress(ESS) distribution was estimated for each of the 11 scaffolds. ESS data were extracted in each circumferential 5-degree subunit of each cross-section in the scaffolded segment. The generalized linear mixed-effect analysis was implemented for the comparison of ESS in two scaffold groups; 150-µm strut thickness MMSES and 125-µm strut thickness MMSES. RESULTS: ESS was significantly higher in MMSES (150 µm) [0.85(0.49-1.40) Pa], compared to MMSES (125 µm) [0.68(0.35-1.18) Pa]. Both MMSES (150 µm) and MMSES (125 µm) revealed low recirculation zone percentages per luminal surface area [3.17% ± 1.97% in MMSES (150 µm), 2.71% ± 1.32% in MMSES (125 µm)]. CONCLUSION: Thinner strut Mirage scaffolds induced lower shear stress due to the small size vessels treated as compared to the thick strut version of the Mirage which was implanted in relatively bigger size vessels. Vessel size should be taken into account in planning BRS implantation. Small vessels may not get benefit from BRS implantation even with a streamlined strut profile. This pilot study warrants comparative assessment with commercially available bioresorbable scaffolds.

Local Hemodynamic Forces After Stenting: Implications on Restenosis and Thrombosis.

Local hemodynamic forces are well-known to modulate atherosclerotic evolution, which remains one of the largest cause of death worldwide. Percutaneous coronary interventions with stent implantation restores blood flow to the downstream myocardium and is only limited by stent failure caused by restenosis, stent thrombosis, or neoatherosclerosis. Cumulative evidence has shown that local hemodynamic forces affect restenosis and the platelet activation process, modulating the pathophysiological mechanisms that lead to stent failure. This article first covers the pathophysiological mechanisms through which wall shear stress regulates arterial disease formation/neointima proliferation and the role of shear rate on stent thrombosis. Subsequently, the article reviews the current evidence on (1) the implications of stent design on the local hemodynamic forces, and (2) how stent/scaffold expansion can influence local flow, thereby affecting the risk of adverse events.

Late thrombotic events after bioresorbable scaffold implantation: a systematic review and meta-analysis of randomized clinical trials.

AIMS: To compare the long-term safety and efficacy of bioresorbable vascular scaffold (BVS) with everolimus-eluting stent (EES) after percutaneous coronary interventions. METHODS AND RESULTS: A systematic review and meta-analysis of randomized clinical trials comparing clinical outcomes of patients treated with BVS and EES with at least 24 months follow-up was performed. Adjusted random-effect model by the Knapp-Hartung method was used to compute odds ratios (OR) and 95% confidence intervals (CI). The primary safety outcome of interest was the risk of definite/probable device thrombosis (DT). The primary efficacy outcome of interest was the risk of target lesion failure (TLF). Five randomized clinical trials (n = 1730) were included. Patients treated with Absorb BVS had a higher risk of definite/probable DT compared with patients treated with EES (OR 2.93, 95%CI 1.37-6.26, P = 0.01). Very late DT (VLDT) occurred in 13 patients [12/996 (1.4%, 95%CI: 0.08-2.5) Absorb BVS vs. 1/701 (0.5%, 95%CI: 0.2-1.6) EES; OR 3.04; 95%CI 1.2-7.68, P = 0.03], 92% of the VLDT in the BVS group occurred in the absence of dual antiplatelet therapy (DAPT). Patients treated with Absorb BVS had a trend towards higher risk of TLF (OR 1.48, 95%CI 0.90-2.42, P = 0.09), driven by a higher risk of target vessel myocardial infarction and ischaemia-driven target lesion revascularization. No difference was found in the risk of cardiac death. CONCLUSION: Compared with EES, the use of Absorb BVS was associated with a higher rate of DT and a trend towards higher risk of TLF. VLDT occurred in 1.4% of the patients, the majority of these events occurred in the absence of DAPT.

Hybrid intravascular imaging: recent advances, technical considerations, and current applications in the study of plaque pathophysiology.

Cumulative evidence from histology-based studies demonstrate that the currently available intravascular imaging techniques have fundamental limitations that do not allow complete and detailed evaluation of plaque morphology and pathobiology, limiting the ability to accurately identify high-risk plaques. To overcome these drawbacks, new efforts are developing for data fusion methodologies and the design of hybrid, dual-probe catheters to enable accurate assessment of plaque characteristics, and reliable identification of high-risk lesions. Today several dual-probe catheters have been introduced including combined near infrared spectroscopy-intravascular ultrasound (NIRS-IVUS), that is already commercially available, IVUS-optical coherence tomography (OCT), the OCT-NIRS, the OCT-near infrared fluorescence (NIRF) molecular imaging, IVUS-NIRF, IVUS intravascular photoacoustic imaging and combined fluorescence lifetime-IVUS imaging. These multimodal approaches appear able to overcome limitations of standalone imaging and provide comprehensive visualization of plaque composition and plaque biology. The aim of this review article is to summarize the advances in hybrid intravascular imaging, discuss the technical challenges that should be addressed in order to have a use in the clinical arena, and present the evidence from their first applications aiming to highlight their potential value in the study of atherosclerosis.

Intracoronary optical coherence tomography: Clinical and research applications and intravascular imaging software overview.

By providing valuable information about the coronary artery wall and lumen, intravascular imaging may aid in optimizing interventional procedure results and thereby could improve clinical outcomes following percutaneous coronary intervention (PCI). Intravascular optical coherence tomography (OCT) is a light-based technology with a tissue penetration of approximately 1 to 3 mm and provides near histological resolution. It has emerged as a technological breakthrough in intravascular imaging with multiple clinical and research applications. OCT provides detailed visualization of the vessel following PCI and provides accurate assessment of post-procedural stent performance including detection of edge dissection, stent struts apposition, tissue prolapse, and healing parameters. Additionally, it can provide accurate characterization of plaque morphology and provides key information to optimize post-procedural outcomes. This manuscript aims to review the current clinical and research applications of intracoronary OCT and summarize the analytic OCT imaging software packages currently available. © 2017 Wiley Periodicals, Inc.

Impact of Implantation Technique and Plaque Morphology on Strut Embedment and Scaffold Expansion of Polylactide Bioresorbable Scaffold　- Insights From ABSORB Japan Trial.

BACKGROUND: The optimal implantation technique for the bioresorbable scaffold (Absorb, Abbott Vascular) is still a matter of debate. The purpose of the present study was to evaluate the effect of implantation technique on strut embedment and scaffold expansion.Methods and Results:Strut embedment depth and scaffold expansion index assessed by optical coherence tomography (OCT) (minimum scaffold area/reference vessel area) were evaluated in the ABSORB Japan trial (OCT subgroup: 87 lesions) with respect to implantation technique using either quantitative coronary angiography (QCA) or OCT. Strut embedment was assessed at the strut level (n=667), while scaffold expansion was assessed at the lesion level (n=81). The mean embedment depth was 63±59 µm. Balloon sizing and inflation pressure had no direct effect on strut embedment. Plaque morphology affected strut embedment [nonatherosclerotic (58.9±54.3 µm), fibroatheroma (73.3±59.6 µm), fibrous plaque (59.7±51.1 µm), and fibrocalcific plaque (-3.1±61.6 µm, negative value means malapposition), P <0.001]. The balloon-artery ratio positively correlated with the expansion index. This relationship was stronger when the OCT-derived reference vessel diameter (RVD) was used as a reference for balloon selection rather than the QCA-derived one [predilatation (Pearson correlation r: QCA: 0.167 vs. OCT: 0.552), postdilatation (QCA: 0.316 vs. OCT: 0.717)]. CONCLUSIONS: Underlying plaque morphology influenced strut embedment, whereas implantation technique had no direct effect on it. Optimal balloon sizing based on OCT-derived RVD might be recommended. However, the safety of such a strategy should be investigated in a prospective trial. (Circ J 2016; 80: 2317-2326).

Edge Vascular Response After Resorption of the Everolimus-Eluting Bioresorbable Vascular Scaffold　- A 5-Year Serial Optical Coherence Tomography Study.

BACKGROUND: The edge vascular response (EVR) has been linked to important prognostic implications in patients treated with permanent metallic stents. We aimed to investigate the relationship of EVR with the geometric changes in the everolimus-eluting bioresorbable scaffold using serial optical coherence tomography (OCT) analysis. METHODS AND RESULTS: In the first-in-man ABSORB trial, 28 patients (29 lesions) underwent serial OCT at 4 different time points (Cohort B1: post-procedure, 6, 24, and 60 months [n=13]; Cohort B2: post-procedure, 12, 36, and 60 months [n=15]) following implantation of the scaffold. In Cohort B1, there was no significant luminal change at the distal or proximal edge segment throughout the entire follow-up. In contrast, there was a significant reduction of the lumen flow area (LFA) of the scaffold between post-procedure and 6 months (-1.03±0.49 mm(2)[P<0.001]), whereas between 6 and 60 months the LFA remained stable (+0.31±1.00 mm(2)[P=0.293]). In Cohort B2, there was a significant luminal reduction of the proximal edge between post-procedure and 12 months (-0.57±0.74 mm(2)[P=0.017]), whereas the lumen area remained stable (-0.26±1.22 mm(2)[P=0.462]) between 12 and 60 months. The scaffold LFA showed a change similar to that observed in Cohort B1. CONCLUSIONS: Our study demonstrated a reduction in the scaffold luminal area in the absence of major EVR, suggesting that the physiological continuity of the lumen contour is restored long term. (Circ J 2016; 80: 1131-1141).