Hoyoun Won

Red blood cell distribution width predicts early mortality in patients with acute dyspnea.

BACKGROUND Red blood cell distribution width (RDW) has been shown to predict clinical outcomes in cardiovascular diseases. We studied whether RDW is useful to predict early mortality in patients with acute dyspnea at an emergency department (ED). METHODS We retrospectively analyzed 907 patients with acute dyspnea who visited the ED from January 2009 to May 2009. Primary outcome was 30-day mortality. RESULTS Acute decompensated heart failure (29.9%) was the most common adjudicated discharge diagnosis followed by cancer (14.8%) and pneumonia (12.5%). There was a stepwise increase of 30-day mortality risk from lowest (RDW<12.9%) to highest (RDW>14.3%) RDW tertiles (1.4% vs. 8.3% vs. 18.3%; log-rank P<0.001). In multivariate Cox hazard analysis, RDW was an independent predictor of 30-day mortality after adjusting for other risk factors (HR 1.23; 95% CI 1.11-1.36; P<0.001). Adding RDW to conventional clinical predictors significantly improved prediction for 30-day mortality as measured by the area under the ROC curve (AUC, from 0.873 to 0.885; P=0.023) and the net reclassification improvement (NRI=14.1%; P<0.001)/integrated discrimination improvement (IDI=0.038; P=0.006). CONCLUSIONS Our findings suggest that RDW measured at ED is an independent and additive predictor of early mortality in patients with acute dyspnea.

Comparison of two different doses of single bolus steroid injection to prevent atrial fibrillation recurrence after radiofrequency catheter ablation.

Purpose Steroids may play a role in preventing the early recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA). However, optimal doses and route of steroid delivery have not yet been determined. This study evaluated the effect of two different doses of a single bolus injection of steroids on AF recurrence after RFCA. Materials and Methods Of 448 consecutive AF patients who underwent RFCA, a single steroid bolus was injected into 291 patients. A low-dose steroid group (n=113) received 100 mg of hydrocortisone and a moderate-dose steroid group (n=174) received 125 mg of methylprednisolone. We used propensity-score matching to select patients as follows: control (n=95), low-dose (n=95), and moderate-dose steroid groups (n=97). Results Pericarditis developed in 1 (1.1%) control patient, 2 (2.1%) low-dose patients and 0 moderate-dose patients. Maximum body temperature and C-reactive protein were significantly decreased in the moderate-dose steroid group compared to the other groups (p<0.01). The number of patients of early AF recurrence (≤3 months) did not differ among three groups. Early recurrence was 24 (25%) in the control, 24 (25%) in the low-dose and 25 (26%) in the medium-dose groups (p=0.99). Compared with control group, low-dose or moderate-dose steroid treatment did not effectively decrease mid-term (3-12 months) AF recurrence [22 (23%) vs. 23 (24%) vs. 18 (19%); p=0.12]. Conclusion A single injection of moderate-dose steroid decreased inflammation. However, single bolus injections of low-dose or moderate-dose steroids were not effective in preventing immediate, early or midterm AF recurrence after RFCA.

Multimodality Intravascular Imaging Assessment of Plaque Erosion versus Plaque Rupture in Patients with Acute Coronary Syndrome

Background and Objectives We assessed plaque erosion of culprit lesions in patients with acute coronary syndrome in real world practice. Subjects and Methods Culprit lesion plaque rupture or plaque erosion was diagnosed with optical coherence tomography (OCT). Intravascular ultrasound (IVUS) was used to determine arterial remodeling. Positive remodeling was defined as a remodeling index (lesion/reference EEM [external elastic membrane area) >1.05. Results A total of 90 patients who had plaque rupture showing fibrous-cap discontinuity and ruptured cavity were enrolled. 36 patients showed definite OCT-plaque erosion, while 7 patients had probable OCT-plaque erosion. Overall, 26% (11/43) of definite/probable plaque erosion had non-ST elevation myocardial infarction (NSTEMI) while 35% (15/43) had ST elevation myocardial infarction (STEMI). Conversely, 14.5% (13/90) of plaque rupture had NSTEMI while 71% (64/90) had STEMI (p<0.0001). Among plaque erosion, white thrombus was seen in 55.8% (24/43) of patients and red thrombus in 27.9% (12/43) of patients. Compared to plaque erosion, plaque rupture more often showed positive remodeling (p=0.003) with a larger necrotic core area examined by virtual histology (VH)-IVUS, while negative remodeling was prominent in plaque erosion. Overall, 65% 28/43 of plaque erosions were located in the proximal 30 mm of a culprit vessel-similar to plaque ruptures (72%, 65/90, p=0.29). Conclusion Although most of plaque erosions show nearly normal coronary angiogram, modest plaque burden with negative remodeling and an uncommon fibroatheroma might be the nature of plaque erosion. Multimodality intravascular imaging with OCT and VH-IVUS showed fundamentally different pathoanatomic substrates underlying plaque rupture and erosion.

Is Stopping Heparin Safe in Patients on Extracorporeal Membrane Oxygenation Treatment

Anticoagulation treatment during extracorporeal membrane oxygenation (ECMO) treatment is unavoidable. However, discontinuation of heparin infusion is necessary when challenges associated with the use of heparin, such as bleeding and thrombocytopenia, are encountered. The medical records of 94 adult (age ≥ 18 years) patients treated with ECMO from January 2011 to March 2015, at Chung-Ang University Hospital, Seoul, Korea, were reviewed. Among the 94 patients, 55 patients underwent ECMO treatment for three or more days. In 52.7% of these patients (n = 29, group A), heparin was stopped for three or more days because of thrombocytopenic events (< 50,000 cells/mm3), higher than target range (> 230 seconds) activated clotting time (ACT), bleeding complications, or the need for other surgical procedures. In 43.6% of patients (n = 24, group B), heparin was continuously infused during the entire ECMO process. The mean length of ECMO support after the initiation of heparin discontinuation in patients in group A was 10.2 ± 14.7 days. There were no intracardiac, intravascular, or intracircuit thrombotic complications in group A. There was no difference in the ECMO weaning success rate between the two groups (41.4% in group A vs. 54.2% in group B, p = 0.353). Heparin discontinuation can be considered in a select group of patients with coagulation abnormalities or bleeding.

Influence of Previous Statin Therapy on Cholesterol-Lowering Effect of Ezetimibe

Background and Objectives The inhibition of cholesterol absorption by ezetimibe increases cholesterol synthesis. The effect of inhibition of cholesterol synthesis on cholesterol absorption is controversial. The influence of these interactions on cholesterol levels is unknown. We investigated on the extent to which cholesterol levels were affected by the reaction of one pathway to the inhibition of the other pathway. Subjects and Methods This case-controlled study enrolled 198 patients who needed cholesterol-lowering drugs. Ezetimibe (10 mg) was administered to the patients with (n=58) and without on-going statin therapy (n=58). Simvastatin (20 mg) was administered to the patients treated with (n=41) and without ezetimibe (n=41). Results Ezetimibe without statin lowered the total cholesterol by 13.3±8.8% (p<0.001) and the low density lipoprotein-cholesterol (LDL-C) by 18.7±15.3% (p<0.001). Ezetimibe added to statin decreased the total cholesterol by 21.1±7.7% (p<0.001) and the LDL-C by 29.9±12.6% (p<0.001). The total cholesterol and LDL-C were reduced more by ezetimibe in patients with statin therapy than in those without statin therapy (p<0.001 and p<0.001, respectively). The differences in the effect of simvastatin on total cholesterol and LDL-C between the patients with and without ezetimibe showed borderline significance (p=0.10 and p=0.055, respectively). Conclusion A prior inhibition of cholesterol synthesis by statin enhanced the effect of ezetimibe on total cholesterol and LDL-C by 7.8% and 11.2%, respectively. This finding suggests that ezetimibe increased cholesterol synthesis, resulting in a significant elevation of cholesterol levels.

Neointimal response to second-generation drug-eluting stents in diabetic patients with de-novo coronary lesions: intravascular ultrasound study.

ObjectivesThe aim of this study was to evaluate the extent of neointimal response after the implantation of a second-generation drug-eluting stent, zotarolimus-eluting stent (ZES-ER, Endeavor Resolute) or everolimus-eluting stent (EES, Xience V), using intravascular ultrasound (IVUS) in diabetic patients. Materials and methodsIn all, 154 diabetic patients with de-novo coronary lesions were randomized to be implanted with a ZES-ER or EES, and the angiographic follow-up at 9 months combined with a complete IVUS study was available for 96 patients with 101 lesions. ResultsBaseline demographic and lesion parameters were similar in both groups at index percutaneous coronary intervention. On follow-up angiography, in-stent late lumen loss and minimal lumen diameter were not different between the two groups. On IVUS study, neointimal hyperplasia volume [median (interquartile range): ZES-ER vs. EES; 2.25 mm3 (0.57–6.25) vs. 1.59 mm3 (0.45–8.37), P=0.615] and in-stent percentage of volume obstruction [median (interquartile range): ZES-ER vs. EES; 1.16% (0.33–3.61) vs. 0.77% (0.29–4.01), P=0.615] showed similar results between the two groups. ConclusionIn diabetic patients, the second-generation drug-eluting stents, ZES-ER and EES, were comparable in inhibiting neointimal proliferation.

Safety and Efficacy of Switching Anticoagulation to Aspirin Three Months after Successful Radiofrequency Catheter Ablation of Atrial Fibrillation

Purpose Although current guidelines recommend continuing the same antithrombotic strategy regardless of rhythm control after radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF), anticoagulation has a risk of major bleeding. We evaluated the safety of switching warfarin to aspirin in patients with successful AF ablation. Materials and Methods Among 721 patients who underwent RFCA of AF, 608 patients (age, 57.3±10.9 years; 77.0% male, 75.5% paroxysmal AF) who had no evidence of AF recurrence at 3 months post-RFCA were included. We compared the thromboembolic and hemorrhagic events in patients for whom warfarin was switched to aspirin (ASA group; n=296) and patients who were kept on warfarin therapy (W group; n=312). Results There were no significant differences in CHA2DS2-VASc or HAS-BLED scores between the groups. In 30 patients in the ASA group and 37 patients in W group, AF recurred and warfarin was restarted or maintained during the 18.0±12.2 months of follow-up. There were no significant differences in thromboembolic (0.3% vs. 1.0%, p=0.342) and major bleeding incidences (0.7% vs. 0.6%, p=0.958) between ASA and W groups during the follow-up period. In the 259 patients with a CHA2DS2-VASc score ≥2, there were no significant differences in thromboembolism (0.8% and 2.2%, p=0.380) or major bleeding incidences (0.8% and 1.4%, p=0.640) between ASA and W groups. Conclusion Switching warfarin to aspirin 3 months after successful RFCA of AF could be as safe and efficacious as long-term anticoagulation even in patients with CHA2DS2-VASc score ≥2. However, strict rhythm monitoring cannot be overemphasized.

Serial Changes of Neointimal Tissue after Everolimus-Eluting Stent Implantation in Porcine Coronary Artery: An Optical Coherence Tomography Analysis

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.

Successful Management of a Rare Case of Stent Fracture and Subsequent Migration of the Fractured Stent Segment Into the Ascending Aorta in In-Stent Restenotic Lesions of a Saphenous Vein Graft

Stent fracture is a complication following implantation of drug eluting stents and is recognized as one of the risk factors for in-stent restenosis. We present the first case of successfully managing a stent fracture and subsequent migration of the fractured stent into the ascending aorta that occurred during repeat revascularization for in-stent restenosis of an ostium of saphenous vein graft after implantation of a zotarolimus-eluting stent. Although the fractured stent segment had migrated into the ascending aorta with a pulled balloon catheter, it was successfully repositioned in the saphenous vein graft using an inflated balloon catheter. Then, the fractured stent segment was successfully connected to the residual segment of the zotarolimus-eluting stent by covering it with an additional sirolimuseluting stent.

Late Stent Thrombosis After Drug-Eluting Stent Implantation: A Rare Case of Accelerated Neo-Atherosclerosis and Early Manifestation of Neointimal Rupture

An 80-year old woman suffered from sudden onset of chest pain and dyspnea, and visited the emergency room. She received stent implantation with a biolimus A9-eluting stent (Nobori® 3.0×24 mm) at a the mid-portion of the left anterior descending artery 5 months prior to admission. The emergency 5-month follow-up angiogram was performed under the impression of late stent thrombosis. The follow-up angiogram showed subtotal occlusion at the mid-portion of the left anterior descending artery, which was the same segment of previous stent implantation 5 months ago. Immediately after thrombus aspiration with the thrombus aspiration catheter, the optical coherence tomography showed layered appearance of neointimal hyperplasia and neointimal rupture within the previously stented segment. Thus, neointimal rupture within accelerated growth of neointimal tissue was observed within a relatively shorter period (i.e., about 5 months) after stent implantation.