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1.  Mitochondrial DNA 4977bp Deletion Mutation in Peripheral Blood Reflects Atrial Remodeling in Patients with Non-Valvular Atrial Fibrillation 
Yonsei Medical Journal  2014;56(1):53-61.
Recently, mitochondrial DNA 4977bp deletion (mtDNA4977-mut), a somatic mutation related to oxidative stress, has been shown to be associated with atrial fibrillation (AF). We hypothesized that patient age, as well as electroanatomical characteristics of fibrillating left atrial (LA), vary depending on the presence of mtDNA4977-mut in peripheral blood among patients with non-valvular AF.
Materials and Methods
Analyzing clinical and electroanatomical characteristics, we investigated the presence of the mtDNA4977-mut in peripheral blood of 212 patients (51.1±13.2 years old, 83.5% male) undergoing catheter ablation for non-valvular AF, as well as 212 age-matched control subjects.
The overall frequency of peripheral blood mtDNA4977-mut in patients with AF and controls was not significantly different (24.5% vs. 19.3%, p=0.197). When the AF patient group was stratified according to age, mtDNA4977-mut was more common (47.4% vs. 20.0%, p=0.019) in AF patients older than 65 years than their age-matched controls. Among AF patients, those with mtDNA4977-mut were older (58.1±11.9 years old vs. 48.8±11.9 years old, p<0.001). AF patients positive for the mtDNA mutation had greater LA dimension (p=0.014), higher mitral inflow peak velocity (E)/diastolic mitral annular velocity (Em) ratio (p<0.001), as well as lower endocardial voltage (p=0.035), and slower conduction velocity (p=0.048) in the posterior LA than those without the mutation. In multivariate analysis, E/Em ratio was found to be significantly associated with the presence of mtDNA4977-mut in peripheral blood.
mtDNA4977-mut, an age-related somatic mutation detected in the peripheral blood, is associated with advanced age and electro-anatomical remodeling of the atrium in non-valvular AF.
PMCID: PMC4276778  PMID: 25510747
Atrial fibrillation; mitochondrial DNA; 4977bp deletion mutation; atrial remodeling
2.  Histological and Biochemical Comparisons between Right Atrium and Left Atrium in Patients with Mitral Valvular Atrial Fibrillation 
Korean Circulation Journal  2014;44(4):233-242.
Background and Objectives
It has been known that the dominant driver of atrial fibrillation (AF) exists in the left atrium (LA) and the incidence of systemic thromboembolism is higher than that of pulmonary thromboembolism in patients with AF. Therefore, we hypothesized that histological and biochemical characteristics of the LA and the right atrium (RA) are different in patients with mitral valvular AF.
Subjects and Methods
We analyzed the histology and messenger ribonucleic acid (mRNA) or protein expression associated with endothelial function and thrombogenesis in 33 human atrial appendage tissues (20 LA tissues, 13 RA tissues) taken from 25 patients {57.7±11.3 years old, 44% males, AF: sinus rhythm (SR)=17:8} with mitral valve disease. We also performed whole mRNA quantification in 8 tissues (both LA and RA tissues from 4 patients) by using next generation sequencing (NGS).
1) The degree of fibrosis (p=0.001) and subendocardial smooth muscle thickness (p=0.004) were significantly greater in the LA than in the RA. 2) More advanced matrix fibrosis was found in the LA of patients with AF than in the LA of patients with SR (p=0.046), but not in the RA. 3) There was no LA-RA difference in protein (Western blot) and mRNA {quantitative real-time polymerase chain reaction (qRT-PCR)} expressions of NF-κB, 3-NT, CD31, E-selectin, inducible NO synthase, stromal cell-derived factor-1α, Endothelin-1, platelet-derived growth factor, myeloperoxidase, or NCX, except for higher mRNA expression of HCN4 in the RA (qRT-PCR, p=0.026) and that of KCNN1 in the LA (NGS, p=0.016).
More advanced matrix and subendocardial remodeling were noticed in the LA than in the RA in patients with mitral valvular AF. However, the expressions of tissue factors associated with thrombogenesis were not significantly different between the RA and the LA.
PMCID: PMC4117844  PMID: 25089135
Atrial fibrillation; Mitral valve disease; Fibrosis; Subendocardium
3.  Endovascular Repair of Aortoiliac Aneurysm Using Bifurcated Stent Grafts with Sandwich Technique for Preserving the Internal Iliac Artery 
Korean Circulation Journal  2013;43(9):628-631.
In this case, we describe a case of a 76-year-old male with extensive aortoiliac aneurysms treated by endovascular aneurysm repair using the sandwich technique in order to preserve left internal iliac artery perfusion. The sandwich technique refers to the deployment of multiple paralleled stent grafts into main distal and side branches in overlapping with a single proximal stent graft. The procedure was successfully performed without complications. Post-procedural CT angiography demonstrated patent stent grafts without any endoleak. The strengths and limitations of the sandwich technique need to be investigated in large-scale, long-term clinical trials.
PMCID: PMC3808859  PMID: 24174964
Endovascular procedures; Stents; Aortic aneurysm; Iliac; Aneurysm
4.  A Case of Abdominal Aortic Aneurysm with Short Angulated Proximal Neck Treated with the Chimney Graft Technique 
Korean Circulation Journal  2013;43(6):416-421.
Endovascular aneurysm repair (EVAR) using stent grafts has shown to be an effective alternative to surgical repair in treating an abdominal aortic aneurysm (AAA). EVAR is associated with shorter hospital stays, less blood loss, shorter operating times, and lower early morbidity and mortality compared to open surgical repair, although EVAR required a higher reintervention rate during a longer follow-up period. However, short or severely an angulated infrarenal proximal aortic neck is considered unsuitable for EVAR. The chimney graft technique is a modified procedure based on the deployment of a covered or bare-metal stent parallel to the main aortic endograft within the aneurysm, thereby creating a conduit that runs outside the aortic main endograft to preserve flow to the aortic branches. In this case report, we present a 78-year-old patient with an AAA with a short and severely angulated proximal neck who was successfully treated by EVAR using the chimney graft technique.
PMCID: PMC3717426  PMID: 23882292
Aortic aneurysm, abdominal; Endovascular techniques
5.  Hybrid Treatment for Thoracic Aortic Aneurysm Combined with Aberrant Right Subclavian Artery 
Korean Circulation Journal  2013;43(1):66-69.
An aberrant right subclavian artery (ARSA) is the most common vascular abnormality of the aortic arch and is associated with development of aneurysms in 3-8% of these anomalies. In this case report, we describe an 84-year-old man with a symptomatic ARSA treated with staged hybrid procedure combining surgical replacement of the ascending aorta and bilateral carotid-to-subclavian artery bypass with implantation of a stent graft in the aortic arch and descending aorta. Our case suggests that a less invasive hybrid therapy can be performed successfully for the treatment of ARSA with aneurysmal change in patients at high surgical risk.
PMCID: PMC3569571  PMID: 23407812
Aberrant right subclavian artery; Aortic aneurysm, thoracic; Endovascular procedures
6.  Serial Plasma Levels of Angiogenic Factors in Patients With ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention 
Korean Circulation Journal  2012;42(7):464-470.
Background and Objectives
Patients with acute myocardial infarction show varying degrees of collateral development. However, the relationships between angiogenic factors and degree of collaterals are not well known.
Subjects and Methods
Fifty-nine patients (mean age, 59±10 years) with ST-segment elevation myocardial infarction (STEMI) underwent primary percutaneous coronary intervention (PCI). Patients were divided into one of 2 groups: group I (Rentrop collateral grade 0/1, n=34) or group II (grade 2/3, n=25). Plasma levels of vascular endothelial growth factor (VEGF), soluble VEGF receptor (sFlt-1), angiopoietin (Ang)-2, and soluble Tie-2 at baseline, 24 and 48 hours after PCI were measured.
There were fewer diabetic patients and higher incidence of previous angina and multi-vessel disease in group II. Group II had a lower left ventricular ejection fraction and a trend toward longer pain-to-balloon time. Plasma levels of Ang-2, sFlt-1 were elevated prior to primary PCI and decreased after PCI, whereas plasma level of VEGF was relatively low initially, however rose after PCI. sTie-2 levels showed no significant interval change in group I, but decreased over time in group II. VEGF, sFlt-1, and Tie-2 levels did not differ between the groups at each time point. However, plasma levels of Ang-2 were higher in group I than in group II at baseline and at 48 hours.
Presence of collaterals in STEMI patients undergoing primary PCI was associated with lesser rise in Ang-2 plasma level. VEGF showed a delayed response to acute ischemia compared to Ang-2. Clinical implications of our findings need to be investigated in further studies.
PMCID: PMC3409395  PMID: 22870080
Myocardial infarction; Angiogenesis modulating agents; Vascular endothelial growth factor; Angiopoietin-2
7.  Effects of Combination Therapy with Celecoxib and Doxycycline on Neointimal Hyperplasia and Inflammatory Biomarkers in Coronary Artery Disease Patients Treated with Bare Metal Stents 
Yonsei Medical Journal  2011;53(1):68-75.
Cyclooxygenase (COX)-2 and matrix metalloproteinase (MMP)-9 play a key role in the pathogenesis of in-stent restenosis. We investigated the effect of a short-term therapy of celecoxib, a COX-2 inhibitor, with or without doxycycline, an MMP inhibitor, after coronary stenting on inflammatory biomarkers and neointimal hyperplasia.
Materials and Methods
A total of 75 patients (86 lesions) treated with bare metal stents were randomized into three groups: 1) combination therapy (200 mg celecoxib and 20 mg doxycycline, both twice daily), 2) celecoxib (200 mg twice daily) only, and 3) non-therapy control. Celecoxib and doxycycline were administered for 3 weeks after coronary stenting. The primary endpoint was neointimal volume obstruction by intravascular ultrasound (IVUS) at 6 months. The secondary endpoints included clinical outcomes, angiographic data, and changes in blood levels of inflammatory biomarkers.
Follow-up IVUS revealed no significant difference in the neointimal volume obstruction among the three treatment groups. There was no difference in cardiac deaths, myocardial infarctions, target lesion revascularization or stent thrombosis among the groups. Blood levels of high-sensitivity C-reactive protein, soluble CD40 ligand, and MMP-9 varied widely 48 hours and 3 weeks after coronary stenting, however, they did not show any significant difference among the groups.
Our study failed to demonstrate any beneficial effects of the short-term therapy with celecoxib and doxycycline or with celecoxib alone in the suppression of inflammatory biomarkers or in the inhibition of neointimal hyperplasia. Large scale randomized trials are necessary to define the role of anti-inflammatory therapy in the inhibition of neointimal hyperplasia.
PMCID: PMC3250318  PMID: 22187234
Celecoxib; coronary artery disease; coronary stent; neointimal hyperplasia; inflammation
9.  Endovascular Treatment of Isolated Common Iliac Artery Aneurysms With Short Necks Using Bifurcated Stent-Grafts 
Korean Circulation Journal  2010;40(7):343-347.
Elective surgical repair has traditionally been considered to be the treatment of choice for the exclusion of isolated iliac artery aneurysms (IAAs). Recently, endovascular repair has evolved as an alternative to surgical repair, especially in patients at high surgical risk. However, in the absence of sufficient proximal necks, iliac artery aneurysms are not suitable for direct deployment of a tubular-shaped endograft. Here we report two cases of IAAs with short proximal necks that were excluded using an endovascular bifurcated stent-graft. The bifurcated stent-graft was successfully deployed with complete exclusion of the aneurysm. In neither case was there evidence of procedural failures. There were no signs of significant complications. We conclude that endovascular repair of IAAs with short proximal necks is feasible and efficient using an endovascular bifurcated stent-graft.
PMCID: PMC2910292  PMID: 20664744
Iliac aneurysm; Stent; Endoluminal repair
10.  Acute Myocardial Infarction due to Polyarteritis Nodosa in a Young Female Patient 
Korean Circulation Journal  2010;40(4):197-200.
Coronary artery aneurysms are uncommon, are usually associated with atherosclerosis, and rarely involve all three major coronary arteries. The present report describes a rare case of a young female patient presenting with acute myocardial infarction (AMI). Coronary angiography revealed multiple severe aneurysmal and stenotic changes. Based on clinical feature and angiographic findings, it was strongly suspected that the patient had polyarteritis nodosa (PAN) complicated by AMI. The patient was treated with standard cardiac medications and immunosuppressive agents and has remained stable without further complications during a follow-up period of 6 months.
PMCID: PMC2859338  PMID: 20421961
Coronary aneurysm; Myocardial infarction; Polyarteritis nodosa; Vasculitis
11.  Outcomes before and after the Implementation of a Critical Pathway for Patients with Acute Aortic Disease 
Yonsei Medical Journal  2016;57(3):626-634.
Acute aortic diseases, such as aortic dissection and aortic aneurysm, can be life-threatening vascular conditions. In this study, we compared outcomes before and after the implementation of a critical pathway (CP) for patients with acute aortic disease at the emergency department (ED).
Materials and Methods
This was a retrospective observational cohort study. The CP was composed of two phases: PRE-AORTA for early diagnosis and AORTA for prompt treatment. We compared patients who were diagnosed with acute aortic disease between pre-period (January 2010 to December 2011) and post-period (July 2012 to June 2014).
Ninety-four and 104 patients were diagnosed with acute aortic disease in the pre- and post-periods, respectively. After the implementation of the CP, 38.7% of acute aortic disease cases were diagnosed via PRE-AORTA. The door-to-CT time was reduced more in PRE-AORTA-activated patients [71.0 (61.0, 115.0) min vs. 113.0 (56.0, 170.5) min; p=0.026]. During the post-period, more patients received emergency intervention than during the pre-period (22.3% vs. 36.5%; p=0.029). Time until emergency intervention was reduced in patients, who visited the ED directly, from 378.0 (302.0, 489.0) min in the pre-period to 200.0 (170.0, 299.0) min in the post-period (p=0.001). The number of patients who died in the ED declined from 11 to 4 from the pre-period to the post-period. Hospital mortality decreased from 26.6% to 14.4% in the post-period (p=0.033).
After the implementation of a CP for patients with acute aortic disease, more patients received emergency intervention within a shorter time, resulting in improved hospital mortality.
PMCID: PMC4800351  PMID: 26996561
Critical pathway; clinical protocol; aorta; aortic dissection; aortic aneurysm; mortality
12.  Percutaneous Coronary Intervention Is More Beneficial Than Optimal Medical Therapy in Elderly Patients with Angina Pectoris 
Yonsei Medical Journal  2016;57(2):382-387.
Data comparing the clinical benefits of medical treatment with those of percutaneous coronary intervention (PCI) in an elderly population with angina pectoris are limited. Therefore, we evaluated the efficacy of elective PCI versus optimal medical treatment (OMT) in elderly patients (between 75 and 84 years old) with angina pectoris.
Materials and Methods
One hundred seventy-seven patients with significant coronary artery stenosis were randomly assigned to either the PCI group (n=90) or the OMT group (n=87). The primary outcome was a composite of major adverse events in the 1-year follow-up period that included cardiovascular death, non-fatal myocardial infarction, coronary revascularization, and stroke.
Major adverse events occurred in 5 patients (5.6%) of the PCI group and in 17 patents (19.5%) of the OMT group (p=0.015). There were no significant differences between the PCI group and the OMT group in cardiac death [hazard ratio (HR) for the PCI group 0.454; 95% confidence interval (CI) 0.041–5.019, p=0.520], myocardial infarction (HR 0.399; 95% CI 0.039–4.050, p=0.437), or stroke (HR 0.919; 95% CI 0.057–14.709, p=0.952). However, the PCI group showed a significant preventive effect of the composite of major adverse events (HR 0.288; 95% CI 0.106–0.785, p=0.015) and against the need for coronary revascularization (HR 0.157; 95% CI 0.035–0.703, p=0.016).
Elective PCI reduced major adverse events and was found to be an effective treatment modality in elderly patients with angina pectoris and significant coronary artery stenosis, compared to OMT.
PMCID: PMC4740530  PMID: 26847290
Percutaneous coronary intervention; elderly patient; angina pectoris
13.  The Beneficial Effect of Renin-Angiotensin-Aldosterone System Blockade in Marfan Syndrome Patients after Aortic Root Replacement 
Yonsei Medical Journal  2015;57(1):81-87.
In this study, we evaluated the long term beneficial effect of Renin-Angiotensin-Aldosterone System (RAAS) blockade therapy in treatment of Marfan aortopathy.
Materials and Methods
We reviewed Marfan syndrome (MFS) patients who underwent aortic root replacement (ARR) between January 1996 and January 2011. All patients were prescribed β-blockers indefinitely. We compared major aortic events including mortality, aortic dissection, and reoperation in patients without RAAS blockade (group 1, n=27) to those with (group 2, n=63). The aortic growth rate was calculated by dividing the diameter change on CT scans taken immediately post-operatively and the latest scan available.
There were no differences in clinical parameters except for age which was higher in patients with RAAS blockade. In group 1, 2 (7%) deaths, 5 (19%) aortic dissections, and 7 (26%) reoperations occurred. In group 2, 3 (5%) deaths, 2 (3%) aortic dissections, and 3 (5%) reoperations occurred. A Kaplan-Meier plot demonstrated improved survival free from major aortic events in group 2. On multivariate Cox, RAAS blockade was an independent negative predictor of major aortic events (hazard ratio 0.38, 95% confidence interval 0.30-0.43, p=0.002). Mean diameter change in descending thoracic and supra-renal abdominal aorta was significantly higher in patients without RAAS blockade (p<0.05).
In MFS patients who underwent ARR, the addition of RAAS blockade to β-blocker was associated with reduction of aortic dilatation and clinical events.
PMCID: PMC4696976  PMID: 26632386
Marfan syndrome; angiotensin receptor blocker; ACE inhibitor; RAAS blockade
14.  Impact of Coronary Plaque Characteristics on Late Stent Malapposition after Drug-Eluting Stent Implantation 
Yonsei Medical Journal  2015;56(6):1538-1544.
To evaluate the impact of pre-procedural coronary plaque composition assessed by virtual histology intravascular ultrasound (VH-IVUS) on late stent malapposition assessed by optical coherence tomography (OCT) following drug-eluting stent (DES) implantation.
Materials and Methods
The study population consisted of 121 patients (121 lesions) who underwent both pre-procedural VH-IVUS and follow-up OCT after DES implantation. The association between pre-procedural plaque composition [necrotic core (NC), dense calcium (DC), fibrotic (FT), and fibro-fatty (FF) volumes] assessed by VH-IVUS and late stent malapposition (percent malapposed struts) or strut coverage (percent uncovered struts) assessed by follow-up OCT was evaluated.
Pre-procedural absolute total NC, DC, FT, and FF plaque volumes were 22.9±19.0, 7.9±9.6, 63.8±33.8, and 16.5±12.4 mm3, respectively. At 6.3±3.1 months post-intervention, percent malapposed and uncovered struts were 0.8±2.5% and 15.3±16.7%, respectively. Pre-procedural absolute total NC and DC plaque volumes were positively correlated with percent malapposed struts (r=0.44, p<0.001 and r=0.45, p<0.001, respectively), while pre-procedural absolute total FT plaque volume was weakly associated with percent malapposed struts (r=0.220, p=0.015). Pre-procedural absolute total DC plaque volume was the only independent predictor of late stent malapposition on multivariate analysis (β=1.12, p=0.002). There were no significant correlations between pre-intervention plaque composition and percent uncovered struts.
Pre-procedural plaque composition was associated with late stent malapposition but not strut coverage after DES implantation. Larger pre-procedural absolute total DC plaque volumes were associated with greater late stent malapposition.
PMCID: PMC4630040  PMID: 26446634
Drug-eluting stent; intravascular ultrasound; optical coherence tomography
15.  Femoropopliteal Artery Stent Fracture with Recurrent In-Stent Reocclusion and Aneurysm Formation: Successful Treatment with Self-Expandable Viabahn Endoprosthesis 
Korean Circulation Journal  2015;45(6):522-525.
Primary stenting in femoropopliteal lesions of intermediate length has recently shown favorable outcomes. However, stent fractures are a concern after bare metal stent implantation. The incidence of stent fracture varies widely (ranging from 2% to 65%) depending on factors such as the treated lesions or stent type and may potentially lead to various complications. We reported a case of stent fracture with complete dislocation combined with recurrent in-stent reocclusion and aneurysm formation in a patient with occlusive disease of the femoropopliteal artery, which was successfully treated with self-expandable endovascular stent graft.
PMCID: PMC4661369  PMID: 26617656
Blood vessel prosthesis; Graft occlusion, vascular; Aneurysm, false
16.  Korean Atrial Fibrillation (AF) Network: Genetic Variants for AF Do Not Predict Ablation Success 
Genomewide association studies have identified several loci associated with atrial fibrillation (AF) and have been reportedly associated with response to catheter ablation for AF in patients of European ancestry; however, associations between top susceptibility loci and AF recurrence after ablation have not been examined in Asian populations. We examined whether the top single nucleotide polymorphisms (SNPs) at chromosomes 4q25 (PITX2), 16q22 (ZFHX3), and 1q21 (KCNN3) were associated with AF in a Korean population and whether these SNPs were associated with clinical outcomes after catheter ablation for AF.
Methods and Results
We determined the association between 4 SNPs and AF in 1068 AF patients who underwent catheter ablation (74.6% male, aged 57.5±10.9 years, 67.9% paroxysmal AF) and 1068 age- and sex-matched controls. The SNPs at the PITX2 and ZFHX3 loci, but not the KCNN3 locus, were significantly associated with AF (PITX2/rs6843082_G: odds ratio 3.41, 95% CI 2.55 to 4.55, P=1.32×10−16; PITX2/rs2200733_T: odds ratio 2.05, 95% CI 1.66 to 2.53, P=2.20×10−11; ZFHX3/rs2106261_A: odds ratio 2.33, 95% CI 1.87 to 2.91, P=3.75×10−14; KCNN3/rs13376333_T: odds ratio 1.74, 95% CI 0.93 to 3.25, P=0.085). Among those patients who underwent catheter ablation for AF, none of the top AF-associated SNPs were associated with long-term clinical recurrence of AF after catheter ablation.
SNPs at the PITX2 and ZFHX3 loci were strongly associated with AF in Korean patients. In contrast to prior reports, none of the 4 top AF-susceptibility SNPs predicted clinical recurrence after catheter ablation.
PMCID: PMC4599462  PMID: 26272656
atrial fibrillation; catheter ablation; genetic polymorphism; phenotype; recurrence
17.  Association of apolipoprotein A5 concentration with serum insulin and triglyceride levels and coronary artery disease in Korean men 
Atherosclerosis  2008;205(2):568-573.
Whereas the relation between apolipoprotein A5 (APOA5) gene polymorphisms and triglycerides (TG) levels is well established, the associations between apoA5 concentrations, TG and coronary artery disease (CAD) remain controversial. Therefore, we investigated these relations in the setting of a case–control study involving Korean males.
ApoA5, TG, insulin, free fatty acid (FFA) and lipoprotein profiles were determined using a cross-sectional design in 777 healthy controls and 367 CAD patients.
Plasma apoA5 concentration was lower in CAD patients than controls (192.7 ± 5.2 vs. 237.2 ± 3.7 ng/ml, P < 0.001). Values in the second and top tertiles of apoA5 were associated with a decreased odds ratio (OR) for CAD when compared with values in the bottom tertile; OR for apoA5 top tertile was 0.33 (95% CI, 0.23–0.47) in the age- and BMI-adjusted model and 0.35 (95% CI, 0.23–0.56) following additional adjustments for smoking, drinking status, blood pressure, TG and HDL-cholesterol. After adjustment for age and BMI, plasma apoA5 concentration was negatively correlated with serum TG (r = −0.188, P < 0.001) and insulin (r = −0.185, P < 0.001) in normotriglyceridemic controls (TG < 150 mg/dL, n = 509) whereas apoA5 was positively correlated with serum TG in hypertriglyceridemic controls (TG ≥150 mg/dL, n = 268) (r = 0.246, P < 0.001) and total CAD patients (r = 0.177, P < 0.01). Regardless of TG levels and CAD status, apoA5 concentration was positively correlated with HDL-cholesterol and FFA levels.
Our data supports an inverse association between plasma apoA5 concentrations and CAD risk, probably due to the observed negative correlations of apoA5 with TGs and insulin, although these correlations were affected by TG levels.
PMCID: PMC4426969  PMID: 19185864
Apolipoprotein A5; Coronary artery disease; Triglycerides; Insulin
18.  Impact of Statin Treatment on Strut Coverage after Drug-Eluting Stent Implantation 
Yonsei Medical Journal  2014;56(1):45-52.
To evaluate the effect of statin treatment on strut coverage after drug-eluting stent (DES) implantation.
Materials and Methods
In this study, 60 patients were randomly assigned to undergo sirolimus-eluting stent (SES) or biolimus-eluting stent (BES) implantation, after which patients were randomly treated with pitavastatin 2 mg or pravastatin 20 mg for 6 months. The degree of strut coverage was assessed by 6-month follow-up optical coherence tomography, which was performed in 52 DES-implanted patients.
The percentages of uncovered struts were 19.4±14.7% in pitavastatin-treated patients (n=25) and 19.1±15.2% in pravastatin-treated patients (n=27; p=0.927). A lower percentage of uncovered struts was significantly correlated with a lower follow-up low-density lipoprotein (LDL) cholesterol level (r=0.486; p=0.009) and a greater decline of the LDL cholesterol level (r=-0.456; p=0.015) in SES-implanted patients, but not in BES-implanted patients. In SES-implanted patients, the percentage of uncovered struts was significantly lower among those with LDL cholesterol levels of less than 70 mg/dL after 6 months of follow-up (p=0.025), but no significant difference in this variable according to the follow-up LDL cholesterol level was noted among BES-implanted patients (p=0.971).
Lower follow-up LDL cholesterol levels, especially those less than 70 mg/dL, might have a protective effect against delayed strut coverage after DES implantation. This vascular healing effect of lower LDL cholesterol levels could differ according to the DES type.
PMCID: PMC4276777  PMID: 25510746
Stent; optical coherence tomography; statin
19.  Serial Changes of Neointimal Tissue after Everolimus-Eluting Stent Implantation in Porcine Coronary Artery: An Optical Coherence Tomography Analysis 
BioMed Research International  2014;2014:851676.
Purposes. The serial changes in neointimal tissues were compared between everolimus-eluting stent (EES) and bare-metal stent (BMS) in the porcine coronary artery using optical coherence tomography (OCT). Methods. Serial (1, 3, and 6 month follow-up after stent implantation) OCT examinations were performed in 15 swine with 15 BMS- and 15 EES-treated lesions in porcine coronary arteries. Results. In BMS-implanted lesions, neointimal volume decreased from 7.3 mm3 to 6.9 mm3 and 6.4 mm3 at 1, 3, and 6 months follow-up without statistical significance (P = 0.369). At the time points of 1, 3, and 6 months, neointimal tissue appearance was mainly a homogeneous pattern (80.0%, 93.3%, and 100%, resp.), while the other pattern was layered. In contrast, in EES-implanted lesions, neointimal volume significantly increased from 4.8 mm3 to 9.8 mm3 between 1 and 3 months but significantly decreased to 8.6 mm3 between 3 and 6 months (P < 0.001). Between 1 and 3 months, the layered pattern of neointimal tissue increased from 26.7% to 66.7% but decreased to 20.0% between 3 and 6 months. Conclusions. EES had a biphasic pattern of neointimal amounts that correlated with changes in neointimal morphology.
PMCID: PMC4182891  PMID: 25309929
20.  Multidisciplinary Team Approach for Identifying Potential Candidate for Transcatheter Aortic Valve Implantation 
Yonsei Medical Journal  2014;55(5):1246-1252.
We sought to evaluate the clinical usefulness of decision making by a multidisciplinary heart team for identifying potential candidates for transcatheter aortic valve implantation (TAVI) in patients with symptomatic severe aortic stenosis.
Materials and Methods
The multidisciplinary team consisted of two interventional cardiologists, two cardiovascular surgeons, one cardiac imaging specialist, and two cardiac anesthesiologists.
Out of 60 patients who were screened as potential TAVI candidates, 31 patients were initially recommended as appropriate for TAVI, and 20 of these 31 eventually underwent TAVI. Twenty-two patients underwent surgical aortic valve replacement (AVR), and 17 patients received only medical treatment. Patients who underwent TAVI and medical therapy were older than those who underwent surgical AVR (p<0.001). The logistic Euroscore was significantly highest in the TAVI group and lowest in the surgical AVR group (p=0.012). Most patients in the TAVI group (90%) and the surgical AVR group (91%) had severe cardiac symptoms, but only 47% in the medical therapy group had severe symptoms. The cumulative percentages of survival without re-hospitalization or all-cause death at 6 months for the surgical AVR, TAVI, and medical therapy groups were 84%, 75%, and 28%, respectively (p=0.007, by log-rank).
TAVI was recommended in half of the potential candidates following a multidisciplinary team approach and was eventually performed in one-third of these patients. One-third of the patients who were initially considered potential candidates received surgical AVR with favorable clinical outcomes.
PMCID: PMC4108808  PMID: 25048481
Endovascular procedures; aortic stenosis; clinical outcomes
21.  Transcatheter Aortic Valve Implantation in a Patient with Previous Mitral Valve Replacement 
Korean Circulation Journal  2014;44(5):344-347.
Transcatheter aortic valve implantation (TAVI) has shown favorable outcomes in patients with severe symptomatic aortic valve stenosis who are at high surgical risk or are unsuitable candidates for open heart surgery. However, concerns exist over treating patients who have previously undergone mitral valve surgery due to the potential interference between the mitral prosthetic valve or ring and the TAVI device. In this case report, we present a patient with symptomatic severe aortic stenosis and previous mechanical mitral valve replacement who was successfully treated with TAVI using a CoreValve.
PMCID: PMC4180612  PMID: 25278988
Aortic valve stenosis; Catheters; Heart valve prosthesis; Prosthesis implantation; Mitral valve
22.  Optical Coherence Tomographic Observation of Morphological Features of Neointimal Tissue after Drug-Eluting Stent Implantation 
Yonsei Medical Journal  2014;55(4):944-952.
The impacts of different time courses and the degree of neointimal growth on neointimal morphology have not yet been sufficiently investigated. Therefore, we evaluated the morphological features of neointimal tissue after drug-eluting stent (DES) implantation using optical coherence tomography (OCT).
Materials and Methods
The morphological features of neointimal tissue in stented segments with a maximal percentage of cross-sectional area (CSA) stenosis of neointima were evaluated in 507 DES-treated lesions with >100 µm mean neointimal thickness on follow-up OCT. Neointimal tissue was categorized as homogeneous, heterogeneous, layered, or neoatherosclerotic.
In lesions with <50% of neointimal CSA stenosis, homogeneous neointima (68.2%) was predominant, followed by heterogeneous neointima (14.1%) and layered neointima (14.1%). In lesions with ≥50% of neointimal CSA stenosis, layered neointima was most frequently observed (68.3%), followed by neoatherosclerotic neointima (25.2%). In subgroup analysis of lesions with ≥50% of neointimal CSA stenosis, 89.5% of the lesions with a stent age <30 months were layered neointima, while 62.3% of the lesions with a stent age ≥30 months were neoatherosclerotic neointima.
This study suggests that the OCT-detected morphology of DES neointimal tissue was different according to the follow-up time course and degree of neointimal hyperplasia.
PMCID: PMC4075398  PMID: 24954322
Optical coherence tomography; stent; coronary artery disease
23.  Comparison of Full Lesion Coverage versus Spot Drug-Eluting Stent Implantation for Coronary Artery Stenoses 
Yonsei Medical Journal  2014;55(3):584-591.
The aim of this study was to evaluate and compare the long-term clinical outcomes of the spot drug-eluting stent (DES) implantation strategy, which is used to minimize implanted stent length and the number of stents, versus full lesion coverage for treatment of coronary artery stenoses.
Materials and Methods
We evaluated 1-year clinical outcomes of 1619 patients with stent implantation for a single coronary lesion. They were divided into two groups: those treated by full lesion coverage (n=1200) and those treated with the spot stenting strategy (n=419). The combined occurrence of 1-year target vessel failure (TVF), including cardiac death, target-vessel related myocardial infarction, or ischemia-driven target-vessel revascularization was evaluated.
The spot DES implantation group had a shorter stent length (23.14±9.70 mm vs. 25.44±13.24 mm, respectively; p<0.001) and a fewer number of stents (1.09±0.30 vs. 1.16±0.41, respectively; p<0.001), even though the average lesion length was similar to the full lesion coverage group (21.36±10.30 mm vs. 20.58±10.97 mm, respectively; p=0.206). Spot DES implantation was superior to full DES coverage with respect to 1-year TVF (1.4% vs. 3.3%, p=0.044). Cox proportional hazard model analysis showed that the risk for 1-year TVF was almost 60% lower among patients who received spot DESs compared to those who received full DES coverage after adjustment for other risk factors (HR=0.40, 95% confidence interval=0.17-0.98; p=0.046).
Minimizing stent length and the number of stents with overlapping by spot DES implantation may result in reduced rates of 1-year TVF, compared with full DES coverage.
PMCID: PMC3990086  PMID: 24719123
Drug-eluting stents; percutaneous coronary intervention; coronary artery disease
24.  Retrograde Distal Superficial Femoral Artery Approach in the Supine Position for Chronic Superficial Femoral Artery Occlusion 
Korean Circulation Journal  2014;44(3):184-188.
Subintimal angioplasty is an effective method for the treatment of long superficial femoral artery (SFA) occlusions. One of the major limiting factors for the success of this procedure is the failure to re-enter the true lumen. The recently introduced luminal re-entry devices provide a high technical success rate, but failures can occur. In such cases, a retrograde popliteal approach can serve as a potential backup option. However, the need to reposition the patient remains a drawback. Here, we report a case of an 81-year-old male with a long SFA occlusion treated using a retrograde distal SFA approach in the supine position after the initial failure of antegrade angioplasty.
PMCID: PMC4037641  PMID: 24876860
Peripheral arterial disease; Femoral artery; Angioplasty
25.  Prospective and Systematic Analysis of Unexpected Requests for Non-Cardiac Surgery or Other Invasive Procedures during the First Year after Drug-Eluting Stent Implantation 
Yonsei Medical Journal  2014;55(2):345-352.
Unexpected requests for non-cardiac surgery requiring discontinuation of dual antiplatelet therapy (DAPT) frequently occur in daily clinical practice. The objectives of this study were to evaluate prevalence, timing and clinical outcomes of such unexpected requests for non-cardiac surgery or other invasive procedures during the first year after drug-eluting stents (DESs) implantation.
Materials and Methods
We prospectively investigated the prevalence, timing and clinical outcomes of unexpected requests for non-cardiac surgery or other procedures during the first year after DESs implantation in 2117 patients.
The prevalence of requested non-cardiac surgery or invasive procedures was 14.6% in 310 requests and 12.3% in 261 patients. Among 310 requests, those were proposed in 11.3% <1 month, 30.0% between 1 and 3 months, 36.8% between 4 and 6 months and 21.9% between 7 and 12 months post-DES implantation. The rates of actual discontinuation of DAPT and non-cardiac surgery or procedure finally performed were 35.8% (111 of 310 requests) and 53.2% (165 of 310 requests), respectively. On multivariate regression analysis, the most significant determinants for actual discontinuation of DAPT were Endeavor zotarolimus-eluting stent implantation with 3-month DAPT (OR=5.54, 95% CI 2.95-10.44, p<0.001) and timing of request (OR=2.84, 95% CI 1.97-4.11, p<0.001). There were no patients with any death, myocardial infarction, or stent thrombosis related with actual discontinuation of DAPT.
Those unexpected requests with premature discontinuation of DAPT were relatively common and continuously proposed during the first year following DES implantation. No death, myocardial infarction or stent thrombosis occurred in patients with actual discontinuation of DAPT.
PMCID: PMC3936620  PMID: 24532502
Antiplatelet therapy; drug-eluting stents; coronary artery disease

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