Karen Witberg

In vivo detection of high-risk coronary plaques by radiofrequency intravascular ultrasound and cardiovascular outcome: results of the ATHEROREMO-IVUS study.

AIMS Acute coronary syndromes (ACS) are mostly caused by plaque rupture. This study aims to investigate the prognostic value of in vivo detection of high-risk coronary plaques by intravascular ultrasound (IVUS) in patients undergoing coronary angiography. METHODS AND RESULTS Between November 2008 and January 2011, IVUS of a non-culprit coronary artery was performed in 581 patients who underwent coronary angiography for ACS (n = 318) or stable angina (n = 263). Primary endpoint was major adverse cardiac events (MACEs) defined as mortality, ACS, or unplanned coronary revascularization. Culprit lesion-related events were not counted. Cumulative Kaplan-Meier incidence of 1-year MACE was 7.8%. The presence of IVUS virtual histology-derived thin-cap fibroatheroma (TCFA) lesions (present 10.8% vs. absent 5.6%; adjusted HR: 1.98, 95% CI: 1.09-3.60; P = 0.026) and lesions with a plaque burden of ≥70% (present 16.2% vs. absent 5.5%; adjusted HR: 2.90, 95% CI: 1.60-5.25; P < 0.001) were independently associated with a higher MACE rate. Thin-cap fibroatheroma lesions were also independently associated with the composite of death or ACS only (present 7.5% vs. absent 3.0%; adjusted HR: 2.51, 95% CI: 1.15-5.49; P = 0.021). Thin-cap fibroatheroma lesions with a plaque burden of ≥70% were associated with a higher MACE rate within (P = 0.011) and after (P < 0.001) 6 months of follow-up, while smaller TCFA lesions were only associated with a higher MACE rate after 6 months (P = 0.033). CONCLUSION In patients undergoing coronary angiography, the presence of IVUS virtual histology-derived TCFA lesions in a non-culprit coronary artery is strongly and independently predictive for the occurrence of MACE within 1 year, particularly of death and ACS. Thin-cap fibroatheroma lesions with a large plaque burden carry higher risk than small TCFA lesions, especially on the short term.

NIRS and IVUS for characterization of atherosclerosis in patients undergoing coronary angiography

OBJECTIVES The aim of this study was to compare the findings of near-infrared spectroscopy (NIRS), intravascular ultrasound (IVUS) virtual histology (VH), and grayscale IVUS obtained in matched coronary vessel segments of patients undergoing coronary angiography. BACKGROUND Intravascular ultrasound VH has been developed to add tissue characterization to the grayscale IVUS assessment of coronary plaques. Near-infrared spectroscopy is a new imaging technique able to identify lipid core-containing coronary plaques (LCP). METHODS We performed NIRS and IVUS-VH pullbacks in a consecutive series of 31 patients with a common region of interest (ROI) between 2 side branches. For each ROI, we analyzed the chemogram blocks by NIRS, plaque area and plaque burden by grayscale IVUS, and tissue types by IVUS-VH. The chemogram block is a summary metric of a 2-mm vertical slice of the chemogram. The value ranges from 0 to 1 according to the presence of lipids and represents the probability of LCP with a color scale from red (low probability) through orange and tan to yellow (high probability). RESULTS Plaque area (mm(2)) increases as percentage VH derived-necrotic core (NC) content (4.6 ± 2.7 vs. 7.4 ± 3.5 vs. 8.6 ± 3.4 vs. 7.9 ± 3.3, grouped in percentage NC quartiles, p<0.001) and chemogram block probability color bin thresholds increase (4.9 ± 3.8 red, 7.3 ± 3.6 orange, 8.1 ± 3.4 tan, and 8.7 ± 3.4 yellow, p<0.001). The correlation between the block chemogram detection of lipid core and percentage NC content by VH was weak (r=0.149). Correction for the presence of calcium does not improve this correlation. CONCLUSIONS Larger plaque area by grayscale IVUS was more often associated with either elevated percentage VH-NC or LCP by NIRS; however, the correlation between the detection of LCP by NIRS and necrotic core by VH is weak.

In vivo findings of tissue characteristics using iMap™ IVUS and virtual histology™ IVUS

1017 Description Intravascular ultrasound (IVUS) with radiofrequency data analysis is a novel technology which allows identification of atherosclerotic plaque components. Todays, tissue characterisation can be achieved using two different IVUS systems: Virtual HistologyTM IVUS (VH, 20 MHz, phased-array transducer, 2.9 F Eagle EyeTM Gold, Volcano Therapeutics, Rancho Cordova, CA, USA), and iMapTM IVUS (iMap, 40 MHz, mechanical-type transducer, 3.2 F Atlantis, Boston Scientific Corporation, Natick, MA, USA). These two methodological approaches so far had not been compared in vivo. The purpose of this paper is to compare overall in vivo findings between these two IVUS radiofrequency based tissue characterisation systems.

A novel method to assess coronary artery bifurcations by OCT: cut-plane analysis for side-branch ostial assessment from a main-vessel pullback.

AIMS In coronary bifurcations assessment, evaluation of side-branch (SB) ostia by an optical coherence tomography (OCT) pullback performed in the main branch (MB) could speed up lesion evaluation and minimize contrast volume. Dedicated software that reconstructs the cross-sections perpendicular to the SB centreline could improve this assessment. We aimed to validate a new method for assessing the SB ostium from an OCT pullback performed in the MB. METHODS AND RESULTS Thirty-one sets of frequency-domain OCT pullbacks from 28 patients, both from the MB and the SB of a coronary artery bifurcation were analysed. Measurements of the SB ostium from the SB pullback were used as a reference. Measurements of the SB ostium from the MB pullback were then performed in a laboratory setting by (i) conventional analysis and (ii) cut-plane analysis, and the measurement error for each analysis was estimated. Correlations of SB ostium measurements acquired from the MB pullback in comparison with reference measurements acquired from the SB pullback were higher with cut-plane analysis compared with conventional analysis, albeit not reaching statistical significance (area: rcut-plane = 0.927 vs. rconventional = 0.870, P = 0.256; mean diameter: rcut-plane = 0.918 vs. rconventional = 0.788, P = 0.056; minimum diameter: rcut-plane = 0.841 vs. rconventional = 0.812, P = 0.734; maximum diameter: rcut-plane = 0.770 vs. rconventional = 0.635, P = 0.316). Cut-plane analysis was associated with lower absolute error than conventional analysis (area: 0.56 ± 0.45, vs. 1.50 ± 1.31 mm(2), P < 0.001; mean diameter: 0.18 ± 0.14 vs. 0.44 ± 0.30 mm, P < 0.001). CONCLUSION Measurements of SB ostium performed in a laboratory setting by cut-plane analysis of an OCT pullback of the main branch have high correlation with reference measurements performed in a SB OCT pullback and lower error compared with conventional analysis.

Calcified nodules: an underrated mechanism of coronary thrombosis?

Coronary thrombosis, typically presenting as acute coronary syndrome, is commonly considered a result of plaque rupture. However, pathologic studies have also suggested other mechanisms, such as plaque erosion and calcified nodules ([1][1]). We present a case of coronary thrombosis in a patient with

Five-Year Optical Coherence Tomography Follow-Up of an Everolimus-Eluting Bioresorbable Vascular Scaffold Changing the Paradigm of Coronary Stenting?

A 58-year-old man, included in cohort A of the Bioabsorbable Vascular Solutions First in Man Clinical Investigation: A Clinical Evaluation of the Bioabsorbable Vascular Solutions Everolimus Eluting Coronary Stent System in the Treatment of Patients With Single de Novo Native Coronary Artery Lesions (ABSORB) trial,1 had undergone implantation of a bioresorbable everolimus-eluting scaffold (BVS; Abbott Vascular, Santa Clara, CA) in June 2006 because of stable angina class III with a positive exercise test (Figure 1). He had a positive family history for coronary artery disease. At implantation, his total cholesterol was 207 mg/dL, his low-density lipoprotein level was 130 mg/dL, and his high-density lipoprotein level was 71 mg/dL. Coronary angiography revealed a single lesion at the middle left anterior descending artery that was treated with a 3.0×12 mm BVS, and he was discharged on a treatment regimen of dual antiplatelet therapy (aspirin clopidogrel) for 6 months and atorvastatin 20 mg. His lipid profile 2 years after implantation showed a total cholesterol of 144.3 mg/dL, a low-density lipoprotein level of 65 mg/dL, and a high-density lipoprotein level of 60 mg/dL. Figure 1. Coronary angiography of the left anterior descending artery before ( A and B ) and after ( C and D ) intervention …

The Rotterdam Radial Access Research: Ultrasound-Based Radial Artery Evaluation for Diagnostic and Therapeutic Coronary Procedures.

Background—Radial artery wall might be damaged after cannulation for cardiac catheterization. We investigated structural changes of the radial artery wall after catheterization to understand whether these might predict radial pulsation loss or occlusion and local pain or functional impairment of the upper extremity. Methods and Results—Ninety patients underwent transradial coronary angiography or intervention and were scanned with a high-resolution 40-MHz ultrasound before cannulation and at 3 hours and 30 days after procedure. Acute injuries of the radial artery occurred in all patients: dissection and intramural hematoma were the most common. However, these phenomena did not predict loss of radial pulsation or occlusion, local pain, or functional impairment at 30 days. Overall, the radial artery lumen was significantly reduced distal to the puncture site. Radial artery intima and total wall thickness increased 3 hours after puncture and persisted at 30 days. Radial occlusion and pulsation loss were observed in 3.9% and 9.2% of patients, respectively, at 30 days. Smaller radial artery lumen at baseline increased the risk of radial pulsation loss at 30 days (odds ratio, 1.23; P=0.049). The number of radial puncture attempts predicted pulsation loss (odds ratio, 2.64; P=0.027), occlusion (odds ratio, 3.49; P=0.022), and symptoms (odds ratio, 2.24; P=0.05) at 30-day follow-up. Conclusions—After catheterization, radial artery puncture site is associated with increased intima and total wall thickness and with modest decrease of inner lumen diameter. Acute injuries of the vessel wall were ubiquitous, but contrary to repeated puncture attempts, did not seem to affect postprocedural radial occlusion or loss of pulsation.

Reproducibility of intravascular ultrasound iMAP for radiofrequency data analysis: Implications for design of longitudinal studies Reproducibility of Intravascular Ultrasound iMAP

Background: iMAP is a new intravascular ultrasound (IVUS) derived technique for tissue characterization using spectral analysis. Since there is a need for reproducibility data to design longitudinal studies, we sought to assess the in vivo reproducibility of this imaging technique. Methods: iMAP (40 MHz, Boston Scientific Corporation) was performed in patients referred for elective percutaneous intervention and in whom a nonintervened vessel was judged suitable for a safe IVUS analysis. Overall 20 patients with 20 non‐angiographically significant lesions were assessed by two independent observers. Five of these 20 patients received an additional iMAP analysis using a new IVUS catheter and using the same catheter after its engagement and reengagement. Results: The interobserver relative difference in plaque area was 2.5%. Limits of agreement for lumen, vessel, and plaque area measurements were 1.62, −2.47 mm2; 2.09, −3.71 mm2; 2.80, −3.72 mm2; respectively. Limits of agreement for fibrotic, lipidic, necrotic, and calcified measurements were 1.32, −1.44 mm2; 0.24, −0.36 mm2; 1.50, −2.26 mm2; 0.09, −0.11 mm2; respectively. The intercatheter and intracatheter relative difference in plaque area were 0.9% and 4.1%, respectively. Although the variability for compositional measurements increased using two different catheters or using the same catheter twice, the variability for compositional measurements keeps always below 10%. Conclusions: Our analysis demonstrates that the geometrical and compositional iMAP analysis is acceptably reproducible.

Safety of optical coherence tomography in daily practice: A comparison with intravascular ultrasound

Aims Previous studies have reported the safety and feasibility of both time-domain optical coherence tomography (TD-OCT) and Fourier-domain OCT (FD-OCT) in highly selected patients and clinical settings. However, the generalizability of these data is limited, and data in unselected patient populations reflecting a routine cathlab practice are lacking. We compared safety of intracoronary FD-OCT imaging to intravascular ultrasound (IVUS) imaging in a large real-world series of consecutive patients who underwent invasive imaging during coronary catheterization in our centre. Methods and results This is a prospective, single-centre registry of patients scheduled for coronary angiography or intervention undergoing intracoronary imaging with FD-OCT or IVUS between April 2008 and December 2013. Intra-procedural and major in-hospital adverse events that could be possibly related to invasive imaging were registered routinely by the operator as part of our clinical report and prospectively recorded in our database. These events were retrospectively individually adjudicated by an independent safety committee. Between April 2008 and December 2013, 13 418 diagnostic or interventional coronary catheterization procedures were performed. Of these, 1142 procedures used OCT and 2476 procedures used IVUS. Invasive imaging-related complications were rare, did not differ between the two imaging methods (OCT: n = 7, 0.6%; IVUS: n = 12, 0.5%; P = 0.6), and were self-limiting after retrieval of the imaging catheter or easily treatable in the catheterization laboratory. No major adverse events, prolongation of hospital stay, or permanent patient harm was observed. Conclusion FD-OCT is safe in an unselected and heterogeneous group of patients with varying clinical settings.

Optical coherence tomography for evaluation of coronary stents in vivo

Coronary optical coherence tomography (OCT) is a light-based imaging modality that emits light in the near-infrared range. Compared with intravascular ultrasound, OCT has an extraordinarily high resolution (nearly tenfold higher), with an axial resolution in the range of 12–15 µm and a lateral resolution of 20–40 µm. The main drawback of OCT is its relatively low penetration power, especially into lipid-rich atherosclerotic tissue. Second-generation OCT systems, known as frequency domain OCT, are now widely available in many catheter laboratories. The hallmark of OCT is its outstanding ability to depict superficial vessel wall structures with high accuracy. In this regard, OCT was used to evaluate stent expansion and stent strut apposition both early and late following stent deployment, as well as neointimal coverage over struts at long-term follow-up. It has discriminated the differences in strut malapposition and strut neointimal coverage among different stent designs and in various strut subsets. Similarly, OCT delineated many forms of vessel wall injury following percutaneous coronary intervention, such as dissections, thrombosis and tissue protrusion between struts. Recently, OCT was used to study the biodegradation of bioresorbable vascular scaffolds. This review focuses on the role of OCT in the in vivo evaluation of coronary stents.