Ung Kim

Intermediate to long-term outcomes of endoluminal stent-graft repair in patients with chronic type B aortic dissection.

Purpose: To assess mid- to long-term clinical results of stent-graft repair in patients with type B aortic dissection. Methods: Retrospective analysis was done on 72 patients (47 men; mean age 55±12 years) who were diagnosed with chronic type B aortic dissection and underwent stent-graft repair from June 1994 to December 2007. Two types of stent-grafts were employed. Prior to 2000, a custom-designed stent-graft composed of self-expanding Z-type stainless steel stents covered with woven polytetrafluoroethylene material was used. Thereafter, a separate-type (modular) manufactured stent-graft was used, consisting of proximal and distal nitinol stents with an unsupported Dacron tube graft in between; the unsupported graft was stented after deployment. Results: Procedural success (completion of the stent-graft deployment at the target area without device failure) was obtained in 97% (70/72). The 2 failures were due to stent migration and tortuous anatomy, respectively. There were persistent type I endoleaks in 6 cases for a clinical success (entry tear exclusion) of 88% (64/72). There was no immediate postprocedural mortality or paraplegia. There was unintended partial left subclavian artery occlusion in 1 case, as well as postprocedural transient renal failure in 1 patient and 2 access-site pseudoaneurysms. Median follow-up was 43 months (range 5–97, mean 64.4±38.8) in 61 patients (3 patients lost to follow-up). Five patients died, 1 of probable aortic rupture in the setting of residual type I endoleak. Overall clinical success (no death, conversion, or endoleak) was achieved in 84% (47/56); of these, 35 (74%) showed complete resolution of the thoracic false lumen, while the other 12 (26%) had a decrease in false lumen diameter. Conclusions: Intermediate to long-term results of stent-graft implantation in patients with chronic type B aortic dissection seem acceptable and may justify the use of this minimally invasive approach as first line therapy in these patients.

Outcomes of endovascular treatment of chronic total occlusion of the infrarenal aorta

BACKGROUND Few reports have been published on the outcomes of endovascular therapy in chronic total occlusion of the aorta. METHODS Endovascular treatment was attempted in 49 patients (40 men and nine women; aged 64.1 ± 10.9 years) with infrarenal aortic occlusion between January 1995 and December 2009. The first attempt at wire passage and balloon angioplasty was usually performed by an antegrade approach through the brachial artery. Stents were implanted with or without intra-arterial administration of thrombolytic agents. We investigated the immediate and midterm outcomes of endovascular therapy for chronic infrarenal aortic occlusions. RESULTS Technical success was achieved in 40 patients (81.6%). Procedural failures were due to wire passage failure in eight patients and to embolization and spinal cord infarction in one. Stents were implanted in 97.5% of patients. Major complications occurred in eight patients (16.3%): two neurologic events (spinal and cerebral infarction), two cases of jailed renal artery after stenting, and one case each of periprocedural death from pneumonia, distal embolization requiring embolectomy, iliac artery rupture requiring implantation of covered stents, and access site pseudoaneurysm treated with surgery. In patients treated successfully, the primary patency rate was 88.4% at 1 year and 80.1% at 3 years. The major amputation rate was 0%. Seven patients (17.5%) required repeat intervention (n = 5) or bypass surgery (n = 2) during the follow-up period. CONCLUSION Endovascular therapy of infrarenal aortic occlusion was feasible in most cases, and midterm patency was favorable. However, because of relatively high procedurally related complication rates, cautious selection of patients and appropriate preventive measures are necessary to improve immediate outcomes.

The Initial Extent of Malapposition in ST-Elevation Myocardial Infarction Treated with Drug-Eluting Stent: The Usefulness of Optical Coherence Tomography

Purpose The aim of this study is to identify the extent of initial malapposition using optical coherence tomography (OCT) in ST-elevation myocardial infarctions (STEMI) treated with different types of drug-eluting stents (DES). Materials and Methods Twenty four STEMI patients that underwent primary percutaneous coronary intervention (PCI) were enrolled. The OCT and intravascular ultrasound (IVUS) were performed within 72 hours after the primary PCI. Distances between the endo-luminal surface of the strut reflection and the vessel wall and the extent of malapposition were measured and analyzed. Results Sirolimus-eluting stents (SES), paclitaxel-eluting stents (PES) and zotarolimus-eluting stents (ZES) were deployed in 7 patients (29%), 7 patients (29%) and 10 patients (42%). In total, 4951 struts in 620 mm single-stent segments were analyzed (1463 struts in SES, 1522 in PES, and 1966 in ZES). In strut analysis by OCT, the incidence of malapposition was 17 % (860/4951) and in stent analysis by IVUS, malapposition rate was 21% (5/24). The malapposition rate of strut level using OCT in 5 patients who had malapposition in IVUS was significantly higher than the 19 of those who had not (32 ± 5% vs. 12 ± 6%, p = 0.001). In addition, the frequency of malapposition was also significantly different (28% in SES, 11% in PES, 10% in ZES, p = 0.001). The use of SES was an independent predictor of malapposed struts. Conclusion The incidence of malapposition using OCT was quite prevalent in STEMI after primary PCI with DES implantation and SES has especially higher rates of malapposition compared to other DESs.

MEASUREMENT OF FREE-CARRIER NONLINEARITIES IN ZNSE BASED ON THE Z-SCAN TECHNIQUE WITH A NANOSECOND LASER

Self-defocusing and nonlinear absorption resulting from two-photon-excited free charge carriers were observed in polycrystalline ZnSe at the low power density of ~ 30 MW/cm(2) by use of the Z-scan technique with nanosecond laser pulses. The total carrier absorption cross section and the variation of refractive index per unit of photoexcited carrier density were estimated to be 0.80 +/- 0.10 x 10(-18) cm(2) and 0.60 +/- 0.15 x 10(-21) cm(3), respectively.

Homing of adipose-derived stem cells to radiofrequency catheter ablated canine atrium and differentiation into cardiomyocyte-like cells.

BACKGROUND AND OBJECTIVES The purpose was to determine whether human adipose-derived stem cells (h-ASCs) can home to the radiofrequency ablated myocardial lesions when injected intravenously and differentiate into cardiomyocyte. METHODS Human adipose tissues were obtained from patients and h-ASCs were isolated and cultured. The phenotype of isolated h-ASCs was identified by flow cytometry. Radiofrequency catheter ablation (RFCA) was performed with ten ablation pulses (40 W, 60 s each) to induce heat-mediated lesions at the free walls of the right atria of 14 dogs. Twenty-four hours after ablation, h-ASCs (1 × 10(7) cells) labeled with superparamagnetic iron oxide particles (SPIOs) were infused intravenously in 10 dogs as cell-therapy group and only saline without cells was infused in 4 dogs as control. The hearts were explanted 4 weeks later. RESULTS h-ASCs were identified by flow cytometry as mesenchymal stem cell as positive for CD 13, CD29, CD44, CD90, CD166 and HLA-ABC and immunophenotyping revealed no immunologic responses. SPIO-labeled cells were identified in areas surrounding the RFCA-induced lesions by Prussian blue staining. Immunohistochemistry staining showed positive for anti-α-actinin, anti-cardiac troponin-I, anti-connexin 43 and anti-VEGFR-2. No lymphocyte infiltration, immunorejection or neoplasm-like cells were found in the h-ASC-positive areas. However, multiple iron-labeled h-ASCs were detected in lungs and spleens of cell-therapy group. CONCLUSION h-ASCs can home into injured atrial tissue and express a cardiomyocyte-like phenotype, suggesting that intravenous delivery of stem cells might be feasible. Functional studies and quantification of delivered stem cells are needed for better evaluation and understanding of differentiation into cardiomyocytes.

Additive beneficial effects of valsartan combined with rosuvastatin in the treatment of hypercholesterolemic hypertensive patients.

Background and Objectives We compared the efficacy and safety of valsartan and rosuvastatin combination therapy with each treatment alone in hypercholesterolemic hypertensive patients. Subjects and Methods Patients who met inclusion criteria were randomized to receive 1 of the following 2-month drug regimens: valsartan 160 mg plus rosuvastatin 20 mg, valsartan 160 mg plus placebo, or rosuvastatin 20 mg plus placebo. The primary efficacy variables were change in sitting diastolic blood pressure (sitDBP) and sitting systolic blood pressure (sitSBP), and percentage change in low-density lipoprotein-cholesterol (LDL-C) in the combination, valsartan, and rosuvastatin groups. Adverse events (AEs) during the study were analyzed. Results A total of 354 patients were screened and 123 of them were finally randomized. Changes of sitDBP by least squares mean (LSM) were -11.1, -7.2, and -3.6 mm Hg, respectively, and was greater in the combination, as compared to both valsartan (p=0.02) and rosuvastatin (p<0.001). Changes of sitSBP by LSM were -13.2, -10.8, and -4.9 mm Hg, and was greater in the combination, as compared to rosuvastatin (p=0.006) and not valsartan (p=0.42). Percentage changes of LDL-C by LSM were -52, -4, and -47% in each group, and was greater in the combination, as compared to valsartan (p<0.001), similar to rosuvastatin (p=0.16). Most AEs were mild and resolved by the end of the study. Conclusion Combination treatment with valsartan and rosuvastatin exhibited an additive blood pressure-lowering effect with acceptable tolerability, as compared to valsartan monotherapy. Its lipid lowering effect was similar to rosuvatatin monotherapy.

Successful percutaneous coronary intervention for acute coronary syndrome in a patient with severe hemophilia a.

Patients with hemophilia generally have a reduced frequency of coronary artery disease compared to the general population. As advances in the management of hemophilia have increased their life expectancy, the prevalence of coronary artery disease also has increased. However, there are no standard treatment guidelines for coronary artery disease in patients with hemophilia, especially in the field of coronary intervention. We report the case of a patient with severe hemophilia A who presented with acute coronary syndrome and was successfully treated with percutaneous coronary intervention.

Outcomes According to Presentation With Versus Without Cardiogenic Shock in Patients With Left Main Coronary Artery Stenosis and Acute Myocardial Infarction

This study is aimed at evaluating 1-year clinical outcomes and their predictors in patients with unprotected left main coronary artery (ULMCA)-related acute myocardial infarction (AMI). In total 248 patients diagnosed with AMI involving the ULMCA as the culprit vessel and registered in the Korean Acute Myocardial Infarction database were enrolled in this study. Patients were divided according to the absence (shock-, n = 206) or presence (shock+, n = 42) of cardiogenic shock at initial presentation. Independent risk factors of in-hospital cardiac death associated with ULMCA-related AMI were elucidated by multivariate regression analysis. In-hospital mortality rates were 8.7% in the shock- group and 47.6% in the shock+ group (p = 0.001). During 1-year follow-up after discharge, major adverse cardiac events developed in 16.3% of patients in the shock- group and 18.2% of patients in the shock+ group (p = 0.828); cardiac death, MI, and ischemia-driven target vessel revascularization were similar between the 2 groups at 1 year. On multivariate analysis, initial shock presentation (odds ratio 8.9, confidence interval 4.1 to 19.2, p = 0.004) and left ventricular ejection fraction <30% (odds ratio 7.6, confidence interval 2.7 to 21.1, p = 0.001) were independent risk factors of in-hospital cardiac death associated with ULMCA-related AMI. In conclusion, almost 1/2 of patients with ULMCA-related AMI presenting with cardiogenic shock had a fatal in-hospital outcome compared to <10% of those without cardiogenic shock; however, clinical outcomes after survival of the in-hospital period were not different between these groups.

Detection of Clopidogrel Hyporesponsiveness Using a Point-of-Care Assay and the Impact of Additional Cilostazol Administration after Coronary Stent Implantation in Diabetic Patients

Background/Aims Impaired responsiveness to clopidogrel is common in patients with type 2 diabetes mellitus (DM). The aim of this study was to evaluate the clinical application of a point-of-care assay to detect impaired responsiveness to clopidogrel after coronary stent implantation in patients with type 2 DM. Methods We measured P2Y12 reaction units (PRU) with the VerifyNow point-of-care assay in 544 consecutive patients undergoing dual or triple (i.e., dual plus cilostazol) anti-platelet therapy after coronary stent implantation. High platelet reactivity (HPR) was defined as a PRU value ≥ 240. Results The mean PRU values were 233.5 ± 83.2 and 190.3 ± 85.5 in patients undergoing dual or triple anti-platelet therapy, respectively (p < 0.001). Patients with DM manifested higher post treatment PRU values (238.3 ± 82.4 vs. 210.8 ± 86.8, p = 0.001) and a higher frequency of HPR (44.8% vs. 31.0%, p = 0.003) as compared to patients without DM. We also found that higher PRU values and a higher frequency of HPR were present in patients with DM who were undergoing both triple and dual anti-platelet therapy. However, the higher post-treatment PRU values observed in patients with DM decreased with triple anti-platelet therapy (219.4 ± 82.5 vs. 247.9 ± 81.1, p = 0.044). Conclusions A point-of-care assay can detect elevated platelet reactivity and impaired responsiveness to clopidogrel in patients with type 2 DM. The addition of cilostazol to dual anti-platelet therapy may decrease post-treatment PRU values in patients with type 2 DM.

Two-Year Clinical Outcomes After Large Coronary Stent (4.0 mm) Placement: Comparison of Bare-Metal Stent Versus Drug-Eluting Stent

The absolute benefit of drug‐eluting stents (DES) in low‐risk patients and lesions is not well established.