Nieves Gonzalo

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.

A bioabsorbable everolimus-eluting coronary stent system (ABSORB): 2-year outcomes and results from multiple imaging methods

BACKGROUND Drug-eluting metallic coronary stents predispose to late stent thrombosis, prevent late lumen vessel enlargement, hinder surgical revascularisation, and impair imaging with multislice CT. We assessed the safety of the bioabsorbable everolimus-eluting stent (BVS). METHODS 30 patients with a single de-novo coronary artery lesion were followed up for 2 years clinically and with multiple imaging methods: multislice CT, angiography, intravascular ultrasound, derived morphology parameters (virtual histology, palpography, and echogenicity), and optical coherence tomography (OCT). FINDINGS Clinical data were obtained from 29 of 30 patients. At 2 years, the device was safe with no cardiac deaths, ischaemia-driven target lesion revascularisations, or stent thromboses recorded, and only one myocardial infarction (non-Q wave). 18-month multislice CT (assessed in 25 patients) showed a mean diameter stenosis of 19% (SD 9). At 2-year angiography, the in-stent late loss of 0.48 mm (SD 0.28) and the diameter stenosis of 27% (11) did not differ from the findings at 6 months. The luminal area enlargement on OCT and intravascular ultrasound between 6 months and 2 years was due to a decrease in plaque size without change in vessel size. At 2 years, 34.5% of strut locations presented no discernible features by OCT, confirming decreases in echogenicity and in radiofrequency backscattering; the remaining apparent struts were fully apposed. Additionally, vasomotion occurred at the stented site and adjacent coronary artery in response to vasoactive agents. INTERPRETATION At 2 years after implantation the stent was bioabsorbed, had vasomotion restored and restenosis prevented, and was clinically safe, suggesting freedom from late thrombosis. Late luminal enlargement due to plaque reduction without vessel remodelling needs confirmation.

Optical coherence tomography patterns of stent restenosis

BACKGROUND Stent restenosis is an infrequent but poorly understood clinical problem in the drug-eluting stent era. The aim of the study was to evaluate the morphologic characteristics of stent restenosis by optical coherence tomography (OCT). METHODS Patients (n = 24, 25 vessels) presenting with angiographically documented stent restenosis were included. Quantitative OCT analysis consisted of lumen and stent area measurement and calculation of restenotic tissue area and burden. Qualitative restenotic tissue analysis included assessment of tissue structure, backscattering and symmetry, visible microvessels, lumen shape, and presence of intraluminal material. RESULTS By angiography, restenosis was classified as diffuse, focal, and at the margins in 9, 11, and 5 vessels, respectively. By OCT, restenotic tissue structure was layered in 52%, homogeneous in 28%, and heterogeneous in 20%. The predominant backscatter was high in 72%. Microvessels were visible in 12%. Lumen shape was irregular in 28% and there was intraluminal material in 20%. The mean restenotic tissue symmetry ratio was 0.58 +/- 0.19. Heterogeneous and low scattering restenotic tissue was more frequent in focal (45.5% and 54.5%, respectively) than in diffuse (0 and 11.1%) and margin restenosis (0 and 0%) (P = .005 for heterogeneous, P = .03 for low scattering). Restenosis patients with unstable angina symptoms presented more frequently irregular lumen shape (60 vs 6.7%, P = .007). Stents implanted </=12 months ago had more frequently restenotic tissue with layered appearance (84.6% vs 16.7%, P = .003). CONCLUSIONS We demonstrate the ability of OCT to identify differential patterns of restenotic tissue after stenting. This information could help in understanding the mechanism of stent restenosis.

Expert review document part 2: methodology, terminology and clinical applications of optical coherence tomography for the assessment of interventional procedures.

This document is complementary to an Expert Review Document on Optical Coherence Tomography (OCT) for the study of coronary arteries and atherosclerosis.1 The goal of this companion manuscript is to provide a practical guide framework for the appropriate use and reporting of the novel frequency domain (FD) OCT imaging to guide interventional procedures, with a particular interest on the comparison with intravascular ultrasound (IVUS).1–4 In the OCT Expert Review Document on Atherosclerosis, a comprehensive description of the physical principles for OCT imaging and time domain (TD) catheters (St Jude Medical, Westford, MA, USA) was provided.1 The main advantage of FD-OCT is that the technology enables rapid imaging of the coronary artery, using a non-occlusive acquisition modality. The FD-OCT catheter (DragonflyTM; St Jude Medical) employs a single-mode optical fibre, enclosed in a hollow metal torque wire that rotates at a speed of 100 r.p.s. It is compatible with a conventional 0.014″ angioplasty guide wire, inserted into a short monorail lumen at the tip. The frequency domain optical coherence tomography lateral resolution is improved in comparison with TD-OCT, while the axial resolution did not change. These features, together with reduced motion artefacts and an increased maximum field of view up to 11 mm, have significantly improved both the quality and ease of use of OCT in the catheterization laboratory.3,4 However, the imaging depth of the FD-OCT is still limited to 0.5–2.0 mm.5 The main obstacle to the adoption of TD-OCT imaging in clinical practice is that OCT cannot image through a blood field, and therefore requires clearing or flushing of blood from the lumen.1 The 6 Fr compatible DragonflyTM FD-OCT catheter is so far the only one in the market, as two other systems from Volcano and Terumo, which …

Atherosclerotic tissue characterization in vivo by optical coherence tomography attenuation imaging

Optical coherence tomography (OCT) is rapidly becoming the method of choice for assessing arterial wall pathology in vivo. Atherosclerotic plaques can be diagnosed with high accuracy, including measurement of the thickness of fibrous caps, enabling an assessment of the risk of rupture. While the OCT image presents morphological information in highly resolved detail, it relies on interpretation of the images by trained readers for the identification of vessel wall components and tissue type. We present a framework to enable systematic and automatic classification of atherosclerotic plaque constituents, based on the optical attenuation coefficient mu(t) of the tissue. OCT images of 65 coronary artery segments in vitro, obtained from 14 vessels harvested at autopsy, are analyzed and correlated with histology. Vessel wall components can be distinguished based on their optical properties: necrotic core and macrophage infiltration exhibit strong attenuation, mu(t)>or=10 mm(-1), while calcific and fibrous tissue have a lower mu(t) approximately 2-5mm(-1). The algorithm is successfully applied to OCT patient data, demonstrating that the analysis can be used in a clinical setting and assist diagnostics of vessel wall pathology.

Incomplete Stent Apposition and Delayed Tissue Coverage Are More Frequent in Drug-Eluting Stents Implanted During Primary Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction Than in Drug-Eluting Stents Implanted for Stable/Unstable Angina: Insights From Optical Coherence Tomography

OBJECTIVES The aim of this study was to compare the frequency of incomplete stent apposition (ISA) and struts not covered by tissue at long-term follow-up (as assessed by optical coherence tomography [OCT]) in drug-eluting stents (DES) implanted during primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) versus DES implanted for unstable and stable angina. BACKGROUND Incomplete stent apposition and the absence of strut endothelialization might be linked to stent thrombosis. DES implanted for STEMI might have a higher risk of thrombosis. METHODS Consecutive patients in whom OCT was performed at least 6 months after DES implantation were included in the study. Stent struts were classified on the basis of the presence or absence of ISA and tissue coverage. RESULTS Forty-seven lesions in 43 patients (1,356 frames, 10,140 struts) were analyzed (49% stable angina, 17% unstable angina, 34% STEMI). Median follow-up time was 9 (range 7 to 72) months. Drug-eluting stents implanted during primary PCI presented ISA more often than DES implanted in stable/unstable angina patients (75% vs. 25.8%, p = 0.001). The frequency of uncovered struts was also higher in the STEMI group (93.8% vs. 67.7%, p = 0.048). On multivariate analysis, DES implantation in STEMI was the only independent predictor of ISA (odds ratio: 9.8, 95% confidence interval: 2.4 to 40.4, p = 0.002) and the presence of uncovered struts at follow-up (odds ratio: 9.5, 95% confidence interval: 1.0 to 90.3, p = 0.049). CONCLUSIONS DES implanted for STEMI had a higher frequency of incompletely apposed struts and uncovered struts as assessed by OCT at follow-up. DES implantation during primary PCI in STEMI was an independent predictor of ISA and the presence of uncovered struts at follow-up.

Optical Coherence Tomography Assessment Of The Acute Effects Of Stent Implantation On The Vessel Wall. A Systematic Quantitative Approach

Objective: To observe and characterise vessel injury after stenting using optical coherence tomography (OCT), to propose a systematic OCT classification for periprocedural vessel trauma, to evaluate its frequency in stable versus unstable patients and to assess its clinical impact during the hospitalisation period. Setting: Stenting causes vessel injury. Design and interventions: All consecutive patients in whom OCT was performed after stent implantation were included in the study. Qualitative and quantitative assessment of tissue prolapse, intra-stent dissection and edge dissection were performed. Results: Seventy-three patients (80 vessels) were analysed. Tissue prolapse within the stented segment was visible in 78/80 vessels (97.5%). Median number of tissue prolapse sites was 8 (IQR 4–19), mean (SD) area 1.04 (0.9) mm2. Intra-stent dissection flaps were visible in 69/80 vessels (86.3%) (median number 3 (IQR 1.25–6), maximum flap length 450 (220) μm). Fifty-five out of 80 vessels (68.8%) showed dissection cavities (median number 2 (IQR 0–4.75), maximum depth 340 (170) μm). Edge dissection was visible in 20 vessels (mean (SD) length flap 744 (439) μm). The frequency of tissue prolapse or intra-stent dissection was similar in stable and unstable patients (95.6% vs 100%, p = 0.5 for tissue prolapse; 91.1% vs 82.9%, p = 0.3 for intra-stent dissection). There were no events during the hospitalisation period. Conclusions: OCT allows a detailed visualisation of vessel injury after stent implantation and enables a systematic classification and quantification in vivo. In this study, frequency of tissue prolapse or intra-stent dissections after stenting was high, irrespective of the clinical presentation of the patients, and was not associated with clinical events during hospitalisation.

Efficacy and Safety of Drug-Eluting Stents in Chronic Total Coronary Occlusion Recanalization: A Systematic Review and Meta-Analysis

OBJECTIVES The aim of this study was to compare the efficacy and safety of drug-eluting stent (DES) and bare-metal stent (BMS) use in chronic total occlusion (CTO) recanalization. BACKGROUND The long-term effectiveness and safety of DES use in CTO recanalization are unclear, and performance of randomized clinical trials in the field is complex. METHODS Major electronic information sources were explored for articles comparing outcomes with DES and BMS use among patients with CTO. Assessed clinical outcomes were death, myocardial infarction, target vessel revascularization, major adverse cardiac events, and stent thrombosis; angiographic outcomes were stent restenosis and stent reocclusion. RESULTS Fourteen comparative studies were identified (a total of 4,394 patients). When compared with BMS, DES significantly reduced risk of major adverse cardiac events (relative risk [RR]: 0.45, 95% confidence interval [CI]: 0.34 to 0.60, p < 0.001) and TVR (RR: 0.40, 95% CI: 0.28 to 0.58, p < 0.001) without increasing death (RR: 0.87, 95% CI: 0.66 to 1.16, p = 0.88) or myocardial infarction (RR: 0.89, 95% CI: 0.54 to 1.46, p = 0.80). This benefit was sustained at >/=3 years of follow-up. Lower RRs for restenosis (RR: 0.25, 95% CI: 0.16 to 0.41, p < 0.001) and stent reocclusion (RR: 0.30, 95% CI: 0.18 to 0.49, p < 0.001) were also observed in the DES group. A strong trend toward a higher rate of stent thrombosis was documented in DES-treated patients (RR: 2.79, 95% CI: 0.98 to 7.97, p = 0.06). CONCLUSIONS DES use in CTO recanalization is associated with significantly fewer major adverse cardiac events and fewer occurrences of target vessel revascularization, restenosis, and stent reocclusion than with BMS. Although a statistical trend toward a higher risk of stent thrombosis was observed, the use of DES in this context seems to be safe, with an overall benefit sustained in the long term.

A Prospective Randomized Trial of Drug-Eluting Balloons Versus Everolimus-Eluting Stents in Patients With In-Stent Restenosis of Drug-Eluting Stents: The RIBS IV Randomized Clinical Trial.

BACKGROUND Treatment of patients with drug-eluting stent (DES) in-stent restenosis (ISR) remains a major challenge. OBJECTIVES This study evaluated the comparative efficacy of drug-eluting balloons (DEB) and everolimus-eluting stents (EES) in patients presenting with DES-ISR. METHODS The study design of this multicenter randomized clinical trial assumed superiority of EES for the primary endpoint, in-segment minimal lumen diameter at the 6- to 9-month angiographic follow-up. RESULTS A total of 309 patients with DES-ISR from 23 Spanish university hospitals were randomly allocated to DEB (n = 154) or EES (n = 155). At late angiography (median 247 days; 90% of eligible patients), patients in the EES arm had a significantly larger minimal lumen diameter (2.03 ± 0.7 mm vs. 1.80 ± 0.6 mm; p < 0.01) (absolute mean difference: 0.23 mm; 95% CI: 0.07 to 0.38) [corrected], net lumen gain (1.28 ± 0.7 mm vs. 1.01 ± 0.7 mm; p < 0.01), and lower percent diameter stenosis (23 ± 22% vs. 30 ± 22%; p < 0.01) and binary restenosis rate (11% vs. 19%; p = 0.06), compared with patients in the DEB arm. Consistent results were observed in the in-lesion analysis. At the 1-year clinical follow-up (100% of patients), the main clinical outcome measure (composite of cardiac death, myocardial infarction, and target vessel revascularization) was significantly reduced in the EES arm (10% vs. 18%; p = 0.04; hazard ratio: 0.58; 95% CI: 0.35 to 0.98), mainly driven by a lower need for target vessel revascularization (8% vs. 16%; p = 0.035). CONCLUSIONS In patients with DES-ISR, EES provided superior long-term clinical and angiographic results compared with DEB. (Restenosis Intra-Stent of Drug-Eluting Stents: Drug-Eluting Balloon vs Everolimus-Eluting Stent [RIBS IV]; NCT01239940).

In vivo assessment of high-risk coronary plaques at bifurcations with combined intravascular ultrasound and optical coherence tomography.

OBJECTIVES This study sought to evaluate the in vivo frequency and distribution of high-risk plaques (i.e., necrotic core rich) at bifurcations using a combined plaque assessment with intravascular ultrasound-virtual histology (IVUS-VH) and optical coherence tomography (OCT). BACKGROUND Pathological examinations have shown that atherosclerotic plaque rich in necrotic core is prone to develop at bifurcations. High-risk plaque detection could be improved by the combined use of a technique able to detect necrotic core (IVUS-VH) and a high-resolution technique that allows the measurement of the fibrous cap thickness (OCT). METHODS From 30 patients imaged with IVUS-VH and OCT, 103 bifurcations were selected. The main branch was analyzed at the proximal rim of the ostium of the side branch, at the in-bifurcation segment and at the distal rim of the ostium of the side branch. Plaques with more than 10% confluent necrotic core by IVUS-VH were selected and classified as fibroatheroma (FA) or thin-cap fibroatheroma (TCFA) depending on the thickness of the fibrous cap by OCT (>65 or < or =65 microm for FA and TCFA, respectively). RESULTS Twenty-seven FA (26.2%) and 18 TCFA (17.4%) were found out of the 103 lesions studied. Overall the percentage of necrotic core decreases from proximal to distal rim (16.8% vs. 13.5% respectively, p = 0.01), whereas the cap thickness showed an inverse tendency (130 +/- 105 microm vs. 151 +/- 68 microm for proximal and distal rim, respectively, p = 0.05). The thin caps were more often located in the proximal rim (15 of 34, 44.1%), followed by the in-bifurcation segment (14 of 34, 41.2%), and were less frequent in the distal rim (5 of 34, 14.7%). CONCLUSIONS The proximal rim of the ostium of the side branch has been identified as a region more likely to contain thin fibrous cap and a greater proportion of necrotic core.