Eveline Regar

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.

Angiographic Findings of the Multicenter Randomized Study With the Sirolimus-Eluting Bx Velocity Balloon-Expandable Stent (RAVEL) Sirolimus-Eluting Stents Inhibit Restenosis Irrespective of the Vessel Size

Background—Restenosis remains the major limitation of coronary catheter-based intervention. In small vessels, the amount of neointimal tissue is disproportionately greater than the vessel caliber, resulting in higher restenosis rates. In the Randomized Study With the Sirolimus-Eluting Bx Velocity Balloon-Expandable Stent (RAVEL) trial, ≈40% of the vessels were small (<2.5 mm). The present study evaluates the relationship between angiographic outcome and vessel diameter for sirolimus-eluting stents. Methods and Results—Patients were randomized to receive either an 18-mm bare metal Bx VELOCITY (BS group, n=118), or a sirolimus-eluting Bx VELOCITY stent (SES group, n=120). Subgroups were stratified into terciles according to their reference diameter (RD; stratum I, RD <2.36 mm; stratum II, RD 2.36 mm to 2.84 mm; stratum III, RD >2.84 mm). At 6-month follow-up, the restenosis rate in the SES group was 0% in all strata (versus 35%, 26%, and 20%, respectively, in the BS group). In-stent late loss was 0.01±0.25 versus 0.80±0.43 mm in stratum I, 0.01±0.38 versus 0.88±0.57 mm in stratum II, and −0.06±0.35 versus 0.74±0.57 mm in stratum III (SES versus BS). In SES, the minimal lumen diameter (MLD) remained unchanged (&Dgr; −0.72 to 0.72 mm) in 97% of the lesions and increased (=late gain, &Dgr;MLD <−0.72 mm) in 3% of the lesions. Multivariate predictors for late loss were treatment allocation (P <0.001) and postprocedural MLD (P = 0.008). Conclusions—Sirolimus-eluting stents prevent neointimal proliferation and late lumen loss irrespective of the vessel diameter. The classic inverse relationship between vessel diameter and restenosis rate was seen in the bare stent group but not in the sirolimus-eluting stent group.

Randomized study to assess the effect of thrombus aspiration on flow area in patients with ST-elevation myocardial infarction: an optical frequency domain imaging study—TROFI trial

AIMS Primary percutaneous coronary intervention (PPCI) with thrombectomy (TB) seems to reduce the thrombus burden, resulting in a larger flow area as measured with optical frequency domain imaging (OFDI). METHODS AND RESULTS In a multi-centre study, 141 patients with ST elevation myocardial infarction <12 h from onset were randomized to either PPCI with TB using an Eliminate catheter (TB: n = 71) or without TB (non-TB: n = 70), having operators blinded for the OFDI results. The primary endpoint was minimum flow area (MinFA) post-procedure assessed by OFDI, defined as: [stent area + incomplete stent apposition (ISA) area] - (intraluminal defect + tissue prolapse area). Sample size was based on the expected difference of 0.72 mm(2) in MinFA. Baseline demographics, pre-procedural quantitative coronary angiography (QCA), and procedural characteristics were well matched between the two groups. On OFDI, the stent area (TB: 7.62 ± 2.23 mm(2), non-TB: 7.05 ± 2.12 mm(2), P = 0.14) and MinFA (TB: 7.08 ± 2.14 mm(2) vs. non-TB: 6.51 ± 1.99 mm(2), Δ0.57 mm(2), P = 0.12) were not different. In addition, the amount of protrusion, intraluminal defect, and ISA area were similar in the both groups. CONCLUSION PPCI with TB was associated with a similar flow area as well as stent area to PPCI without TB.

Angiographic and Optical Coherence Tomography Insights Into Bioresorbable Scaffold Thrombosis Single-Center Experience

Background—As bioresorbable vascular scaffolds (BVSs) are being increasingly used in complex real-world lesions and populations, BVS thrombosis cases have been reported. We present angiographic and optical coherence tomography (OCT) findings in a series of patients treated in our center for definite bioresorbable scaffold thrombosis. Methods and Results—Up to June 2014, 14 patients presented with definite BVS thrombosis in our center. OCT was performed in 9 patients at the operator’s discretion. Angiographic and OCT findings were compared with a control group comprising 15 patients with definite metallic stent thrombosis. In the BVS group, time interval from index procedure to scaffold thrombosis ranged from 0 to 675 days. Incomplete lesion coverage by angiography was identified in 4 of 14 cases, malapposition by OCT in 5 of 9 cases, strut discontinuity in 2 of 9 cases, and underexpansion in 2 of 9 cases. Five patients had discontinued dual antiplatelet therapy, and in 3 of them discontinued dual antiplatelet therapy discontinuation had occurred the week preceding the event. There were no significant differences in angiographic or OCT findings between BVS and metallic stent thrombosis. Conclusions—Suboptimal implantation with incomplete lesion coverage, underexpansion, and malapposition comprises the main pathomechanism for both early and late BVS thrombosis, similar to metallic stent thrombosis. Dual antiplatelet therapy discontinuation seems to also be a secondary contributor in several late events. Our observations suggest that several potential triggers for BVS thrombosis could be avoided.

Rapamycin eluting stent: the onset of a new era in interventional cardiology

Drug eluting stents represent one of the fastest growing fields in interventional cardiology today. At the congress of the European Society of Cardiology in Amsterdam in 2000, I (PWS) was asked to give the Andreas Gruentzig Lecture. In the week preceding the lecture, we re-angiographied patients 32 and 33 of the initial cohort of patients who had received a rapamycin eluting stent in Sao Paulo and in Rotterdam. Scrutinising the 4–6 month angiographic and ultrasonic results of these patients, I became overwhelmingly convinced that we were the privileged witnesses of a new phenomenon: the almost complete abolition of intra-stent neointimal proliferation. Colleagues, invasive and non-invasive cardiologists, old friends, and financial analysts were surprised by the unusual “excess of enthusiasm” coming from somebody who has built over the years a reputation as a critical assessor, never one to be carried away by the hype of a new wave in interventional cardiology. In the history of this field I have recognised (and “got excited” by, as my American colleagues used to put it) only two revolutionary developments: the introduction of the moveable and steerable guidewire by John Simpson, and the advent of the stent (Palmaz-Schatz, Wallstent). The drug eluting stent is the third such development, and almost one year later I would like to restate the fact that we are entering a new era in interventional cardiology. Why? Because the principle of an eluting stent is sound, and because the three major technical challenges have been mastered—the controlled release of an efficient drug from a stable coating. Drug administration for the prevention of restenosis has been tested in the past—with disappointing results throughout. A proposed explanation for the repeated failure of clinical drug studies has been that agents given systematically cannot reach sufficient concentrations in injured arteries, which has a signficant impact …

First use in patients of a combined near infra-red spectroscopy and intra-vascular ultrasound catheter to identify composition and structure of coronary plaque

A 70 year-old diabetic female with a history of hyperlipidaemia treated with statin therapy underwent coronary angioplasty of her right coronary artery (RCA, Figure 1). Post-procedure the RCA was assessed using, for the first time, a combination intravascular ultrasound (IVUS) and near infrared spectroscopy (NIRS) catheter, which indicated that the proximal end of the stent was located in an area of lipid core plaque (Figure 2 and Video 1); a potential risk factor for stent thrombosis.1 Prospective studies are needed to assess the risk of ending a stent in a fibroatheroma, and to investigate the use of NIRS-IVUS to determine the optimal landing zone for a stent. In this manner, the co-localization of lipid core with structure may provide useful information that will enhance the safety of stenting and, with prospective studies, increase the ability to correctly identify plaque at risk of rupture.

Optical Coherence Tomography Findings at 5-Year Follow-Up After Coronary Stent Implantation

Optical coherence tomography (OCT) is an in vivo, high-resolution imaging modality (resolution, 12 μm; wavelength, 1300 nm; probe size, 0.018 inch; Lightlab Imaging). The principle is analogous to that of pulse-echo ultrasound imaging; however light is used rather than sound to create the image. The case presented illustrates the 5-year follow-up examination after bare metal stent implantation (Figure 1). Intravascular ultrasound imaging (IVUS) shows concentric, moderate neointimal hyperplasia (Figure 2). Intravascular …

The diagnostic value of intracoronary optical coherence tomography

Optical coherence tomography (OCT) is a novel light-based imaging modality for application in the coronary circulation. Compared to conventional intravascular ultrasound, OCT has a ten-fold higher image resolution. This advantage has seen OCT successfully applied in the assessment of atherosclerotic plaque, stent apposition, and tissue coverage, heralding a new era in intravascular coronary imaging. The present article discusses the diagnostic value of OCT, both in cardiovascular research as well as in potential clinical application.The unparalleled high image resolution and strong contrast between the coronary lumen and the vessel wall structure enable fast and reliable image interpretation. OCT makes it possible to visualize the presence of atherosclerotic plaque in order to characterize the structure and extent of coronary plaque and to quantify lumen dimensions, as well as the extent of lumen narrowing, in unprecedented detail. Based on optical properties, OCT is able to distinguish different tissue types, such as fibrous, lipid-rich, necrotic, or calcified tissue. Furthermore, OCT is able to cover the visualization of a variety of features of atherosclerotic plaques that have been associated with rapid lesion progression and clinical events, such as thin cap fibroatheroma, fibrous cap thickness, dense macrophage infiltration, and thrombus formation. These unique features allow the use of OCT to assess patients with acute coronary syndrome and to study the dynamic nature of coronary atherosclerosis in vivo and over time. This permits new insights into plaque progression, regression, and rupture, as well as the study of effects of therapies aimed at modulating these developments.Today’s OCT technology allows high detail resolution as well as fast and safe clinical image acquisition. These unique features have established OCT as the gold standard for the assessment of coronary stents. This technique makes it possible to study stent expansion, peri-procedural vessel trauma, and the interaction of the stent with the vessel wall down to the level of individual stent struts, both acutely as well as in the long term, where it is has proven extremely sensitive to the detection of even minor amounts of tissue coverage. These qualities render OCT indispensable to addressing vexing clinical questions such as the relationship of drug-eluting stent deployment, vascular healing, the true time course of endothelial stent coverage, and late stent thrombosis. This may also better guide the optimal duration of dual anti-platelet therapy that currently remains unclear and relatively empirical.In the future, OCT might emerge, parallel to its undisputed position in research, as the tool of choice in all clinical scenarios where angiography is limited by its nature as a two-dimensional luminogram.ZusammenfassungDie intrakoronare optische Kohärenztomographie (OCT) ist ein relativ neues optisches Verfahren zur Beurteilung der Koronarmorphologie. OCT erstellt, ähnlich wie die konventionelle intrakoronare Ultraschallbildgebung, ein Querschnittsbild der Gefäßwand, mit einer 10-fach höheren Auflösung. Der Beitrag fasst die Erkenntnisse zum diagnostischen Vermögen der OCT zusammen und bewertet sie im Hinblick auf eine mögliche breitere klinische Anwendung.OCT erlaubt eine klare und detaillierte Darstellung endoluminaler Strukturen. Atherosklerotische Plaques können schon im frühen Stadium sicher erkannt und detailliert erfasst werden. Verschiedene Plaquekomponenten können aufgrund ihrer optischen Eigenschaften verlässlich typisiert werden, in lipidreiches, nekrotisches, verkalktes und fibröses Gewebe. Darüber hinaus können morphologische Marker, die in Studien mit klinischen Ereignissen assoziiert wurden, wie ausgedehnte Fibroatherome, dünne fibröse Kappen, Makrophageninfiltrationen und Thromben diagnostiziert werden. Mit diesem diagnostischen Profil ermöglicht OCT Analysen bei akutem Koronarsyndrom und vor allem longitudinale Untersuchungen zum Verständnis von Plaqueprogression, -regression sowie -ruptur und ihrer therapeutischen Modifikation. Wegen der hohen Detailauflösung von OCT etablierte sich diese Methode rasch zum neuen Goldstandard zur Beurteilung von Koronarstents, sowohl im akuten als auch im Langzeitverlauf. OCT erlaubt die Analyse individueller Stent-Struts, ihrer Apposition und Neointimabekleidung im Lauf der Zeit. Diese Informationen sind wertvoll für die Entwicklung von Koronarstents, aber auch zur Therapie von Stentrestenose und Thrombose. In Zukunft können diese Einblicke möglicherweise auch zu einer Optimierung der antithrombozytären Therapie beitragen.Die hohe Detailauflösung sowie die schnelle, patienten- und anwenderfreundliche Bildgebung machen die OCT, neben ihrer längst akzeptierten Rolle in der Forschung, prinzipiell attraktiv für eine breitere klinische Anwendung in all den Situationen, in denen die Angiographie aufgrund ihres zweidimensionalen Luminogrammcharakters limitiert ist.

Combined optical coherence tomography and intravascular ultrasound radio frequency data analysis for plaque characterization. Classification accuracy of human coronary plaques in vitro

This study was performed to characterize coronary plaque types by optical coherence tomography (OCT) and intravascular ultrasound (IVUS) radiofrequency (RF) data analysis, and to investigate the possibility of error reduction by combining these techniques. Intracoronary imaging methods have greatly enhanced the diagnostic capabilities for the detection of high-risk atherosclerotic plaques. IVUS RF data analysis and OCT are two techniques focusing on plaque morphology and composition. Regions of interest were selected and imaged with OCT and IVUS in 50 sections, from 14 human coronary arteries, sectioned post-mortem from 14 hearts of patients dying of non-cardiovascular causes. Plaques were classified based on IVUS RF data analysis (VH-IVUSTM), OCT and the combination of those. Histology was the benchmark. Imaging with both modalities and coregistered histology was successful in 36 sections. OCT correctly classified 24; VH-IVUS 25, and VH-IVUS/OCT combined, 27 out of 36 cross-sections. Systematic misclassifications in OCT were intimal thickening classified as fibroatheroma in 8 cross-sections. Misclassifications in VH-IVUS were mainly fibroatheroma as intimal thickening in 5 cross-sections. Typical image artifacts were found to affect the interpretation of OCT data, misclassifying intimal thickening as fibroatheroma or thin-cap fibroatheroma. Adding VH-IVUS to OCT reduced the error rate in this study.

Very late bioresorbable scaffold thrombosis after discontinuation of dual antiplatelet therapy

A 57-year-old gentleman was admitted with unstable angina with dynamic ECG changes (E), 4 days after discontinuation of dual antiplatelet therapy (DAT) with aspirin and clopidogrel. He had undergone staged percutaneous coronary intervention with bioresorbable vascular scaffold (BVS; ABSORB 1.1, Abbott Vascular, Santa Clara, CA, USA) implantation in the ostial left circumflex artery (LCx) 2 years ago ( Panels A–D ), followed by everolimus-eluting metal stent implantation in …