Showing papers by "Ik-Kyung Jang published in 2014"

Comprehensive overview of definitions for optical coherence tomography-based plaque and stent analyses.

Abstract: Optical coherence tomography (OCT) is the current state-of-the-art intracoronary imaging modality that allows visualization of detailed morphological characteristics of both atherosclerotic plaque and stent. So far, three expert review documents have been released for standardization of OCT image an

Endothelial shear stress and coronary plaque characteristics in humans: combined frequency-domain optical coherence tomography and computational fluid dynamics study.

Abstract: Background— Despite the exposure of the entire vasculature to the atherogenic effects of systemic risk factors, atherosclerotic plaques preferentially develop at sites with disturbed flow. This study aimed at exploring in vivo the relationship between local endothelial shear stress (ESS) and coronary plaque characteristics in humans using computational fluid dynamics and frequency-domain optical coherence tomography. Methods and Results— Three-dimensional coronary artery reconstruction was performed in 21 patients (24 arteries) presenting with acute coronary syndrome using frequency-domain optical coherence tomography and coronary angiography. Each coronary artery was divided into sequential 3-mm segments and analyzed for the assessment of local ESS and plaque characteristics. A total of 146 nonculprit segments were evaluated. Compared with segments with higher ESS [≥1 Pascal (Pa)], those with low ESS (<1 Pa) showed higher prevalence of lipid-rich plaques (37.5% versus 20.0%; P =0.019) and thin-cap fibroatheroma (12.5% versus 2.0%; P =0.037). Overall, lipid plaques in segments with low ESS had thinner fibrous cap (115 μm [63–166] versus 170 μm [107–219]; P =0.004) and higher macrophage density (normalized standard deviation: 8.4% [4.8–12.6] versus 6.2% [4.2–8.8]; P =0.017). Segments with low ESS showed more superficial calcifications (minimum calcification depth: 93 μm [50–140] versus 152 μm [105–258]; P =0.049) and tended to have higher prevalence of spotty calcifications (26.0% versus 12.0%; P =0.076). Conclusions— Coronary regions exposed to low ESS are associated with larger lipid burden, thinner fibrous cap, and higher prevalence of thin-cap fibroatheroma in humans. Frequency-domain optical coherence tomography–based assessment of ESS and wall characteristics may be useful in identifying vulnerable coronary regions. Clinical Trial Registration— URL: . Unique identifier: [NCT01110538][1]. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01110538&atom=%2Fcirccvim%2F7%2F6%2F905.atom

Imaging Plaques to Predict and Better Manage Patients With Acute Coronary Events

Abstract: Culprit lesions of patients, who have had an acute coronary syndrome commonly, are ruptured coronary plaques with superimposed thrombus. The precursor of such lesions is an inflamed thin-capped fibroatheroma. These plaques can be imaged by means of invasive techniques, such as intravascular ultrasound (and derived techniques), optical coherence tomography, and near-infrared spectroscopy. Often these patients exhibit similar (multiple) plaques beyond the culprit lesion. These remote plaques can be assessed noninvasively by computed tomographic angiography and MRI and also using invasive imaging. The detection of these remote plaques is not only feasible but also in natural history studies have been associated with clinical coronary events. Different systemic pharmacological treatments have been studied (mostly statins) with modest success and, therefore, newer approaches are being tested. Local treatment for such lesions is in its infancy and larger, prospective, and randomized trials are needed. This review will describe the pathological and imaging findings in culprit lesions of patients with acute coronary syndrome and the assessment of remote plaques. In addition, the pharmacological and local treatment options will be reviewed.

Comparison of near‐infrared spectroscopy and optical coherence tomography for detection of lipid

Abstract: Objectives To compare intracoronary near-infrared spectroscopy (NIRS) and optical coherence tomography (OCT) for the detection of lipid, to identify NIRS signals to differentiate superficial lipid, and to characterize the plaque with yellow block (YB) chemograms on NIRS. Background Intracoronary NIRS has been developed to detect lipid core plaque (LCP). Methods We investigated a total of 17 patients who underwent both OCT and NIRS. NIRS analysis included plaque lipid core burden index (LCBI), LCP length, and the presence of YB on the block chemogram. OCT analysis included maximum lipid arc (LA), the length of lipid (LL), lipid index, and the thinnest fibrous cap thickness (FCT). Results Twenty-five plaques with >40% plaque burden were analyzed. LCP, showing LCBI > 0, was observed in 20 plaques (80%) and YB was detected in seven plaques (28%). Plaque LCBI showed modest correlations with maximum LA and lipid index by OCT (r2 = 0.319, P = 0.003 and r2 = 0. 404, P = 0.001, respectively). Lipid length showed a significant correlation between NIRS and OCT measurements (r2 = 0.581, P < 0.001). There was no significant difference in NIRS parameters between superficial and deep lipid. Plaques with YB compared with those without YB showed a larger LA, longer LL, and thinner FCT (185 ± 29° vs. 105 ± 76°, P = 0.014; 8.5 ± 3.3 mm vs. 3.3 ± 2.7 mm, P = 0.001; 112 ± 42 vs. 166 ± 61 µm, P = 0.033). Conclusions NIRS and OCT parameters showed modest linear correlations in the measurement of lipid. The accurate depth of lipid in the vessel wall could not be identified by quantitative NIRS parameters. YB chemograms represented more vulnerable features on OCT. © 2013 Wiley Periodicals, Inc.

Comparison by Optical Coherence Tomography of the Frequency of Lipid Coronary Plaques in Current Smokers, Former Smokers, and Nonsmokers

Abstract: Smoking is associated with high incidence of cardiovascular events including acute coronary syndrome. We sought to characterize coronary plaques in patients with ongoing smoking using optical coherence tomography (OCT) compared with former smokers and nonsmokers. We identified 465 coronary plaques from 182 subjects who underwent OCT imaging for all 3 coronary arteries. Subjects were divided into 3 groups: current smokers (n = 41), former smokers (n = 67), and nonsmokers (n = 74). OCT analysis included the presence of lipid-rich plaque, thin-cap fibroatheroma (TCFA), calcification, maximum lipid arc, lipid core length, lipid index, and fibrous cap thickness. Lipid index was defined by mean lipid arc multiplied by lipid core length. Compared with former smokers and nonsmokers, the incidence of lipid plaques and TCFA was significantly higher in current smokers (lipid plaques: 68.0% vs 45.9% and 52.6%, p = 0.002; TCFA: 18.4% vs 7.6% and 9.9%, p = 0.018). There was a trend for higher plaque disruption in current smokers. Former smokers were more likely to have calcified plaques than current and nonsmokers (52.9% vs 32.0% and 38.0%, p = 0.001). In a multivariate analysis, current smoking, low-density lipoprotein, and presentation with acute coronary syndrome were independently associated with the presence of TCFAs. In conclusion, current smokers are more likely to have lipid plaques and OCT-defined vulnerable plaques (TCFAs). Former smokers have increased number of calcified plaques. These results may explain the increased risk of acute cardiac events among smokers.

Computer-Aided Image Analysis Algorithm to Enhance In Vivo Diagnosis of Plaque Erosion by Intravascular Optical Coherence Tomography

Abstract: Background— Recent reports show that plaque erosion can be diagnosed in vivo using optical coherence tomography in patients with acute coronary syndrome. However, quantitative optical coherence tomographic image criteria for computer-aided diagnosis of plaque erosion have not been established. Methods and Results— A total of 42 patients with acute coronary syndrome caused by plaque erosion were included. Plaque erosion was identified according to the previously established optical coherence tomography criteria. Both optical properties and morphological features of the focal-eroded region as well as erosion-adjacent region were analyzed using a custom-designed computer algorithm. Noneroded fibrous plaques remote from the erosion site within the same vessel were used as controls. Eroded plaques have significantly lower surface intensity ( P <0.001), lower region of interest intensity ( P <0.001), lower surface normalized SD ( P <0.001), lower region of interest normalized SD ( P <0.001), higher optical attenuation ( P <0.001), larger tissue protrusion area ( P <0.001), and greater surface roughness ( P <0.001) when compared with control plaques. Erosion-adjacent regions also have lower region of interest normalized SD ( P =0.008), higher attenuation ( P <0.001), and greater surface roughness ( P =0.005). Using a logistic regression model built on the quantitative features, plaque erosion can be accurately classified against intact fibrous plaques. There was low inter- and intraobserver variability associated with the algorithm-assisted quantitative assessment. Conclusions— Plaque erosion has distinctive optical properties and morphological features when compared with noneroded fibrous plaques. Quantitative image analysis may enhance diagnostic accuracy for plaque erosion in vivo.

Is lipoprotein-associated phospholipase A2 activity correlated with fibrous-cap thickness and plaque volume in patients with acute coronary syndrome?

Abstract: Background Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a specific biomarker specific for vascular inflammation. Inflammation has a significant association with plaque progression. The fibrous-cap thickness (FCT) is one of the major determinants of plaque vulnerability in atherosclerotic plaques. However, data on the relationship between Lp-PLA2 activity and FCT in lipid plaque are limited. This study aimed to evaluate the in-vivo association between changes in Lp-PLA2 activity and FCT and plaque volume in patients with acute coronary syndrome (ACS). Patients and methods Twenty-four consecutive patients with ACS were enrolled between May 2010 and May 2012. The plaque volume and FCT of nonculprit lipid-rich plaques were assessed by intravascular ultrasound and optical coherence tomography, respectively, at baseline and after 12 months. Lp-PLA2 activity was determined using the colorimetric assay kit. Results During the 12 months of observation, FCT increased significantly from baseline to follow-up, with a mean percent change of 74.4±46.8%. A significant correlation was observed between changes in Lp-PLA2 activity and changes in FCT (r=-0.56, P=0.006). Changes in plaque volume were also correlated significantly with changes in Lp-PLA2 activity during the study period (r=0.52, P=0.01). Conclusion Significant associations between serial changes in Lp-PLA2 activity and changes in FCT and plaque volume were observed in patients with ACS.

Plaque Erosion: In Vivo Diagnosis and Treatment Guided by Optical Coherence Tomography

Abstract: A 60-year-old man was transferred to the catheterization laboratory after a witnessed ventricular fibrillation arrest. The electrocardiogram was remarkable for ST-segment elevations in leads II, III, aVF, and V6, with reciprocal ST-segment depression in leads V1 to V4 and aVL ([Fig. 1][1]). The

Nonangiographic assessment of coronary artery disease: a practical approach to optical coherence tomography and fractional flow reserve.

Abstract: In an era of increased scrutiny of the appropriateness and safety of revascularization, interventional cardiologists must evolve by adding key tools to their armamentarium. This review highlights the utility of optical coherence tomography and fractional flow reserve in the catheterization lab and provides a practical guide for using these technologies during coronary intervention in various lesion subsets. We propose that fractional flow reserve informs the decision to intervene and optical coherence tomography guides the optimization of the outcome. Coron Artery Dis 25: 608-618 (C) 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Cardiac Catheterization, Coronary Arteriography and Intravascular Diagnostics

Abstract: Cardiac catheterization is currently the gold standard diagnostic procedure for assessing cardiac function and coronary anatomy It is also a platform for the treatment of coronary artery disease peripheral vascular disease and, increasingly, structural heart disease

Different vascular responses within the same stent detected by optical coherence tomography.

Abstract: Case report A 73-year-old man with a history of three-vessel coronary artery bypass surgery in 2001 and two previously placed drug-eluting stents in his saphenous vein graft to the right posterior descending artery in 2010 presented with several days of accelerating angina. Coronary angiogram revealed a focal hazy lesion in the distal right posterior descending artery graft (Fig. 1, white arrow). Optical coherence tomography (OCT) was performed before percutaneous coronary intervention (see Video, Supplemental digital content 1, http://links.lww.com/MCA/A5, longitudinal view of OCT pullback) and demonstrated distinct vascular responses within the previous stent. Heterogeneous low-signal attenuation with a diffuse border consistent with neoatherosclerosis (Fig. 2b, red asterisk) was visualized adjacent to a ruptured fibrous cap (Fig. 2b, yellow arrow) and empty necrotic core (Fig. 2b, white asterisk). In addition, malapposition (Fig. 2c, white arrow) and covered stent struts with minimal neointimal hyperplasia (Fig. 2d, white arrow) were seen.

Coronary Computed Tomographic Angiography for Noninvasive Follow-up of Spontaneous Coronary Artery Dissection

Abstract: Clinical History A 55 year-old woman without known risk factors developed sudden-onset, 3/10 chest pressure in the setting of a recent family tragedy. Her electrocardiogram revealed apical and inferior nonspecific T-wave changes. Troponin-T peaked at 2.4 mg/dL. Emergent invasive coronary angiography was consistent with a distal left anterior descending coronary dissection without significant stenosis. Echocardiography confirmed globally preserved left ventricular function, but apical inferior wall hypokinesis. She was conservatively managed and discharged on dual-antiplatelet therapy, statin, beta-blockade, and ACE inhibitor. At a 1 month outpatient follow-up visit, she noted intermittent chest discomfort. Coronary CT angiography (CTA) was requested to exclude extension of the dissection.