Sun-Joo Jang

High frame-rate intravascular optical frequency-domain imaging in vivo.

Intravascular optical frequency-domain imaging (OFDI), a second-generation optical coherence tomography (OCT) technology, enables imaging of the three-dimensional (3D) microstructure of the vessel wall following a short and nonocclusive clear liquid flush. Although 3D vascular visualization provides a greater appreciation of the vessel wall and intraluminal structures, a longitudinal imaging pitch that is several times bigger than the optical imaging resolution of the system has limited true high-resolution 3D imaging, mainly due to the slow scanning speed of previous imaging catheters. Here, we demonstrate high frame-rate intravascular OFDI in vivo, acquiring images at a rate of 350 frames per second. A custom-built, high-speed, and high-precision fiber-optic rotary junction provided uniform and high-speed beam scanning through a custom-made imaging catheter with an outer diameter of 0.87 mm. A 47-mm-long rabbit aorta was imaged in 3.7 seconds after a short contrast agent flush. The longitudinal imaging pitch was 34 μm, comparable to the transverse imaging resolution of the system. Three-dimensional volume-rendering showed greatly enhanced visualization of tissue microstructure and stent struts relative to what is provided by conventional intravascular imaging speeds.

Impact of heart failure with normal ejection fraction on the occurrence of ischaemic stroke in patients with atrial fibrillation

Objectives The purpose of this study is to examine the risk of stroke in patients with heart failure with normal ejection fraction (HFNEF) and atrial fibrillation (AF). Design Clinical and echocardiographic data in patients with non-valvular AF who were not on anticoagulation were retrospectively investigated. A total of 304 patients had AF without heart failure, and 102 patients were diagnosed as AF with HFNEF. Main outcome measures We compared the rate of ischaemic stroke, death and composite of these in the two groups. Results Patients with AF and HFNEF were older than those with AF only (71.6 vs 64.0 years, p<0.001). Female sex, diabetes mellitus, hypertension, chronic kidney disease, angina, myocardial infarction, use of β blocker or digoxin were more common in patients with AF and HFNEF. The rates of ischaemic stroke, death and composite of ischaemic stroke and death were higher in patients with AF and HFNEF than in those with AF only (20.6% vs 6.7%, p<0.001; 27.2% vs 2.0%, p<0.001; 41.2% vs 8.1%, p<0.001 at 3 years for AF with HFNEF vs AF only, respectively). After adjustment with propensity score method using the inverse probability of treatment weighting, the 3-year risks of for ischaemic stroke (HR 3.29; 95% CI 1.58 to 6.86; p=0.001), death (HR 5.52; 95% CI 2.24 to 13.63; p<0.001), and composite of ischaemic stroke and death (HR 4.08; 95% CI 2.30 to 7.26; p<0.001) were significantly higher in patients with AF and HFNEF. Conclusions HFNEF is associated with an increased risk of stroke and death in patients with AF.

Differential long-term outcomes of zotarolimus-eluting stents compared with sirolimus-eluting and paclitaxel-eluting stents in diabetic and nondiabetic patients: Two-year subgroup analysis of the ZEST randomized trial

To evaluate the differential treatment effects of zotarolimus‐eluting stents (ZES), sirolimus‐eluting stents (SES), and paclitaxel‐eluting stents (PES) according to diabetic status.

Association of early systolic blood pressure response to exercise with future cardiovascular events in patients with uncomplicated mild-to-moderate hypertension

The relationship between blood pressure (BP) response during exercise and future cardiovascular events remains unclear. We assessed the association between an increase in early systolic BP (SBP) during exercise tests and future cardiovascular events in patients with sustained hypertension (sHT). Between 2002 and 2005, we enrolled 300 patients newly diagnosed with mild-to-moderate sHT without complications from the Asan Ambulatory Blood Pressure Monitoring registry. All the patients successfully performed treadmill tests, achieving target heart rate according to the Naughton/Balke protocol. The patients were divided into quartiles according to their SBP at 8 min (7.4 metabolic equivalent tasks). The primary outcome was the composite of all-cause death, new-onset ischemic heart disease and stroke. The 5-year survival rates did not differ significantly among quartiles 1–4 (100% vs. 96.6% vs. 94.4% vs. 98.3%, P=0.211). Relative to quartile 1, the 5-year event-free survival rates were significantly lower in patients in quartiles 3 (86.9% vs. 98.3%, P=0.023) and 4 (88.2% vs. 98.3%, P=0.023). After multivariable adjustment for covariates, the risk for the composite end point was higher for patients in quartiles 3 (Hazard ratio (HR) 4.69, 95% confidence interval (CI) 1.28–17.13, P=0.020) and 4 (HR 3.65, 95% CI 0.92–14.50, P=0.065) than in quartiles 1 and 2. Cardiovascular risk was significantly higher in patients with stage 4 SBP (>180 mm Hg) even after adjustment (HR 4.00, 95% CI 1.19–13.44, P=0.025). Increased submaximal SBP response to exercise may be a predictor of future cardiovascular events in patients with mild-to-moderate sHT.

Factors Influencing Physical Activity among Community-dwelling Older Adults with Type 2 Diabetes: A Path Analysis

PURPOSE The purpose of the study was to identify factors influencing physical activity among community-dwelling older adults with type 2 diabetes. The study design was based on the Theory of Triadic Influence. METHODS A total of 242 older adults with type 2 diabetes participated in this study. Six variables related to physical activity in older adults, including self-efficacy, social normative belief, attitudes, intention, experience, and level of physical activity, were measured using reliable instruments. Data were analyzed using descriptive statistics, Pearsons correlation analyses, and a path analysis. RESULTS The mean physical activity score was 104.2, range from zero to 381.21. The path analysis showed that self-efficacy had the greatest total effect on physical activity. Also, experience had direct and total effects on physical activity as well as mediated the paths of social normative beliefs to attitudes and intention to physical activity. These factors accounted for 10% of the total variance, and the fit indices of the model satisfied the criteria of fitness. CONCLUSION The findings of the study reveal the important role of self-efficacy and past experience in physical activity in older adults with type 2 diabetes.

Dual-wavelength band spectroscopic optical frequency domain imaging using plasmon-resonant scattering in metallic nanoparticles

We demonstrate a dual-wavelength band optical frequency domain imaging (OFDI) system that provides high-resolution spectroscopic imaging with metallic nanoparticles as exogenous contrast agents. The local increase of the OFDI signal by elastic scattering from two different custom-fabricated nonspherical nanoparticles resonant at each wavelength band of the system was successfully detected, and we were able to distinguish and visualize the location of each of the nanoparticles in a scattering sample and in biological tissue.

Plasma treatment effect on angiogenesis in wound healing process evaluated in vivo using angiographic optical coherence tomography

Non-thermal atmospheric pressure plasma holds promise for promoting wound healing. However, plasma-induced angiogenesis, which is important to better understand the underlying physics of plasma treatment effect on wound healing, remains largely unknown. We therefore evaluated the effect of non-thermal plasma on angiogenesis during wound healing through longitudinal monitoring over 30 days using non-invasive angiographic optical coherence tomography imaging in vivo. We demonstrate that the plasma-treated vascular wound area of mouse ear was noticeably decreased as compared to that of control during the early days in the wound healing process. We also observed that the vascular area density was increased in the plasma affected region near the wound as compared to the plasma unaffected region. The difference in the vascular wound area and the vascular area density peaked around day 3. This indicates that the plasma treatment induced additional angiogenic effects in the wound healing process especially during...

Disseminated Mycobacterium intracellulare Infection in an Immunocompetent Host

Disseminated Mycobacterium avium complex (MAC) infection can occur in immunocompromised patients, and rarely in immunocompetent subjects. Due to the extensive distribution of the disease, clinical presentation of disseminated MAC may mimic malignancies, and thorough examinations are required in order to make accurate diagnosis. We report a case of disseminated Mycobacterium intracellulare disease in an immunocompetent patient, which involved the lung, lymph nodes, spleen, and multiple bones. F-18 fluorodeoxyglucose positron-emission tomography imaging showed multiple hypermetabolic lesions, which are suggestive of typical hematogenous metastasis. However, there was no evidence of malignancy in serial biopsies, and M. intracellulare was repeatedly cultured from respiratory specimens and bones. Herein, we should know that disseminated infection can occur in the immunocompetent subjects, and it can mimic malignancies.

Fatal Rhabdomyolysis in a Patient with Liver Cirrhosis after Switching from Simvastatin to Fluvastatin

HMG-CoA reductase inhibitors (statins) are widely used to treat hypercholesterolemia. Among the adverse effects associated with these drugs are statin-associated myopathies, ranging from asymptomatic elevation of serum creatine kinase to fatal rhabdomyolysis. Fluvastatin-induced fatal rhabdomyolysis has not been previously reported. We describe here a patient with liver cirrhosis who experienced fluvastatin-induced fatal rhabdomyolysis. This patient had been treated with simvastatin (20 mg/day) for coronary artery disease and was switched to fluvastatin (20 mg/day) 10 days before admission. He was also taking aspirin, betaxolol, candesartan, lactulose, and entecavir. Rhabdomyolysis was complicated and continued to progress. He was treated with massive hydration, urine alkalization, intravenous furosemide, and continuous renal replacement therapy for acute renal failure, but eventually died due to rhabdomyolysis complicated by hepatic failure. In conclusion, fluvastatin should be used with caution in patients with liver cirrhosis, especially with other medications metabolized with CYP2C9.

Characterization of lipid-rich plaques using spectroscopic optical coherence tomography

Abstract. Intravascular optical coherence tomography (IV-OCT) is a high-resolution imaging method used to visualize the internal structures of walls of coronary arteries in vivo. However, accurate characterization of atherosclerotic plaques with gray-scale IV-OCT images is often limited by various intrinsic artifacts. In this study, we present an algorithm for characterizing lipid-rich plaques with a spectroscopic OCT technique based on a Gaussian center of mass (GCOM) metric. The GCOM metric, which reflects the absorbance properties of lipids, was validated using a lipid phantom. In addition, the proposed characterization method was successfully demonstrated in vivo using an atherosclerotic rabbit model and was found to have a sensitivity and specificity of 94.3% and 76.7% for lipid classification, respectively.