Jinhee Ahn

Effects of Intracoronary Administration of Autologous Adipose Tissue-Derived Stem Cells on Acute Myocardial Infarction in a Porcine Model.

Purpose Adipose-derived stem cells (ADSCs) are known to be potentially effective in regeneration of damaged tissue. We aimed to assess the effectiveness of intracoronary administration of ADSCs in reducing the infarction area and improving function after acute transmural myocardial infarction (MI) in a porcine model. Materials and Methods ADSCs were obtained from each pigs abdominal subcutaneous fat tissue by simple liposuction. After 3 passages of 14-days culture, 2 million ADSCs were injected into the coronary artery 30 min after acute transmural MI. At baseline and 4 weeks after the ADSC injection, 99mTc methoxyisobutylisonitrile-single photon emission computed tomography (MIBI-SPECT) was performed to evaluate the left ventricular volume, left ventricular ejection fraction (LVEF; %), and perfusion defects as well as the myocardial salvage (%) and salvage index. At 4 weeks, each pig was sacrificed, and the heart was extracted and dissected. Gross and microscopic analyses with specific immunohistochemistry staining were then performed. Results Analysis showed improvement in the perfusion defect, but not in the LVEF in the ADSC group (n=14), compared with the control group (n=14) (perfusion defect, -13.0±10.0 vs. -2.6±12.0, p=0.019; LVEF, -8.0±15.4 vs. -15.9±14.8, p=0.181). There was a tendency of reducing left ventricular volume in ADSC group. The ADSCs identified by stromal cell-derived factor-1 (SDF-1) staining were well co-localized by von Willebrand factor and Troponin T staining. Conclusion Intracoronary injection of cultured ADSCs improved myocardial perfusion in this porcine acute transmural MI model.

Comparison of transradial and transfemoral coronary intervention in octogenarians with acute myocardial infarction

BACKGROUND The transradial (TR) approach for percutaneous coronary intervention (PCI) is challenging and associated with failure in elderly patients. We compared the TR and transfemoral (TF) approaches in patients>80 years with acute myocardial infarction (MI) undergoing PCI. METHODS A total of 1945 (7.2%) octogenarians were enrolled from among 27,129 patients in the Korea Acute Myocardial Infarction Registry. The TR group (n=336, 17.3%) was compared with the TF group (n=1609, 82.7%) in the overall and propensity-matched cohorts with respect to procedural success, complications, in-hospital mortality, and one-year mortality and total major adverse cardiac event (MACE; death, MI, and revascularization) rate. RESULTS In the overall cohort, the TR group had lower incidence of Killip class III or IV compared to the TF group. The disease extent and lesion severity were similar between groups, as was the procedural success rate (97.7% vs. 98.3%); however, in-hospital complications were significantly lower in the TR group (8.1% vs. 20.3%). In-hospital mortality was significantly lower in the TR group than the TF group (3.4% vs. 11.4%), as were the one-year mortality and total MACE (9.8% vs. 18.4% and 13% vs. 21.9%, respectively). These outcomes were consistent in the propensity-matched cohort. The TR approach was found to be a significant predictor of low in-hospital mortality (OR 0.355, 95% CI 0.139-0.907), but not of one-year mortality (OR 0.644, 95% CI 0.334-1.240). CONCLUSIONS In octogenarians with acute MI undergoing PCI, the TR approach was more effective than the TF approach as it had lower complication rate and better clinical outcomes with comparable procedural success.

Effectiveness of beta-blockers depending on the genotype of congenital long-QT syndrome: A meta-analysis.

Background Beta-blockers are first-line therapy in patients with congenital long-QT syndrome (LQTS). Objective This study sought to determine the differences in effectiveness of beta-blockers on risk reduction according to LQTS genotype. Methods We searched MEDLINE, EMBASE, and CENTRAL databases to investigate the use of beta-blockers (atenolol, nadolol, propranolol, and metoprolol) in patients with LQTS. Hazard ratio (HR) and relative risk (RR) were extracted or calculated from studies reporting cardiac events (syncope, aborted cardiac arrest (ACA), or sudden cardiac death (SCD)). Results Among 2,113 articles searched, 10 studies (7 registry-based cohort studies (Cohort) and 3 interrupted time series studies (ITS)) involving 9,727 patients were included. In a meta-analysis using a random-effect model, the use of beta-blocker was associated with significant risk reduction of all cardiac events (HR 0.49, p<0.001 in Cohort; RR 0.39, p<0.001 in ITS) and serious cardiac events (ACA or SCD) (HR 0.47, p<0.001 in Cohort). In both LQT1 and LQT2, the risk was reduced with beta-blocker therapy in Cohort (HR 0.59 in LQT1; HR 0.39 in LQT2) as well as ITS (RR 0.29 in LQT1; RR 0.48 in LQT2). Among the beta-blockers, nadolol showed a significant risk reduction in both LQT1 and LQT2 (HR 0.47 and 0.27, respectively), whereas atenolol and propranolol decreased the risk only in LQT1 (HR 0.36 and 0.46, respectively). Metoprolol showed no significant reduction in either genotype. In LQT3, beta-blocker therapy was not as effective as LQT1 or LQT2; however, it was inconclusive due to data insufficiency. Conclusion This meta-analysis showed that beta-blockers were effective in reducing risk of cardiac events in patients with LQTS. Among them, nadolol was effective in LQT1 and LQT2, whereas other drugs showed different effectiveness depending on LQT genotype.

Impact of initial glycosylated hemoglobin level on cardiovascular outcomes in prediabetic patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention.

BackgroundThe prognostic value of the glycemic control level, as measured using glycosylated hemoglobin (HbA1c) level, in prediabetic patients with acute coronary syndrome is still undetermined. The aim of this study was to demonstrate the influence of HbA1c level at admission on the incidence of major adverse cardiac events (MACE) in prediabetic patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI). Methods and resultsUsing data from the Korea Working Group on Myocardial Infarction (February 2008–December 2011), this observational study included 2470 STEMI patients undergoing primary PCI who had not been diagnosed with diabetes mellitus either before or after admission (HbA1c at admission <6.5%). Patients were divided into two groups based on HbA1c at admission: prediabetic (5.7%⩽HbA1c⩽6.4%, n=1475, 59.5%) and nondiabetic (HbA1c<5.7%, n=995, 40.5%). After analyzing the matched cohort, 1-year cumulative MACE incidence, defined as a composite of mortality, nonfatal myocardial infarction, repeated PCI, or coronary artery bypass graft, MACE was not found to differ significantly between the two groups (6.7 vs. 6.0%, P=0.616). Using multivariate logistic analysis, HbA1c level at admission was not significantly associated with the occurrence of MACE (odds ratio 0.925, 95% confidence interval 0.618–1.384, P=0.925). ConclusionThis study demonstrated that HbA1c level at admission was not significantly associated with cardiovascular outcomes in prediabetic Korean populations with STEMI undergoing primary PCI.

Atrial fibrillation cycle length as a predictor for the extent of substrate ablation

AIMS Atrial fibrillation (AF) cycle length (CL) has been demonstrated to be one of the predictors for termination during ablation for AF. We evaluated the AF CL gradient between right atrium (RA) and left atrium (LA) and their mean AF CL in predicting the extent of substrate ablation. METHODS AND RESULTS One-hundred and thirty-six patients undergoing first ablation for persistent AF were studied. Stepwise ablation, sequentially in the following order: pulmonary veins (PV), LA, and RA, was performed to achieve AF termination. Stepwise ablation terminated AF in 110 patients (81%). In the AF termination group, AF was terminated by PV isolation (PVI) (Group P), PVI plus LA ablation (Group L), and PVI plus LA plus RA ablation (Group R) in 14 patients (13%), 49 patients (44%), and 47 patients (43%), respectively. Group R had much shorter mean AF CL than Group L (156 ± 18 vs. 174 ± 24 ms, P < 0.001) and mean AF CL in Group L was much shorter than Group P (174 ± 24 vs. 209 ± 36 ms, P = 0.004). The RA to LA AF CL gradient was not significantly different between left-side ablation (Group P + Group L) and additional RA ablation (Group R) (P = 0.177). Mean AF CL >180.50 ms predicted AF termination by PVI (Group P) with 79% sensitivity and 84% specificity while mean AF CL >165.25 ms predicted AF termination by left-side ablation (Group P + Group L) with 67% sensitivity and 75% specificity. After a mean follow-up of 15 ± 7 months, freedom from arrhythmia recurrence was significantly higher in left-side ablation (Group P + Group L) than additional RA ablation (Group R) (P = 0.024). CONCLUSION Baseline mean AF CL may identify the subset of patients in whom persistent AF can be terminated by different extent of substrate ablation, which may in turn predict the chance of recurrence. However, baseline RA to LA AF CL gradient cannot predict the need for additional RA ablation.

Effect of n-3 Polyunsaturated Fatty Acids on Regression of Coronary Atherosclerosis in Statin Treated Patients Undergoing Percutaneous Coronary Intervention.

Background and Objectives Statins remain the mainstay of secondary coronary artery disease (CAD) prevention, but n-3 polyunsaturated fatty acids (ω-3 PUFA) display biological effects that may also reduce the risk of atherosclerosis and CAD. However, data on the possible antiatherosclerotic benefits of adding ω-3 PUFA to statin therapy are limited. This study aimed to investigate the potential additive effects of ω-3 PUFA on regression of atherosclerosis in CAD patients receiving statin therapy and stent implantation. Subjects and Methods Seventy-four CAD patients undergoing percutaneous coronary intervention (PCI) with stent implantation were enrolled, prescribed statins, and randomly assigned to two groups: n-3 group (ω-3 PUFA 3 g/day, n=38) or placebo group (placebo, n=36). All patients completed the study follow-up consisting of an intravascular ultrasound at baseline and at 12 months. Results There was no difference in the baseline characteristics and distribution of other medications. No significant differences were observed in primary endpoints, including changes in atheroma volume index (−12.65% vs. −8.51%, p=0.768) and percent atheroma volume (−4.36% vs. −9.98%, p=0.526), and in secondary endpoints including a change in neointimal volume index (7.84 vs. 4.94 mm3/mm, p=0.087). Conclusion ω-3 PUFA had no definite additional effect on the regression of coronary atherosclerosis when added to statin in CAD patients undergoing PCI.

Long‐term Outcome of Catheter Ablation for Atrial Fibrillation in Patients with Apical Hypertrophic Cardiomyopathy

Atrial fibrillation (AF) is a common manifestation in cases of hypertrophic cardiomyopathy (HCM). Catheter ablation (CA) for AF in patients with asymmetric septal HCM (SeHCM) is selectively effective and often needs a repeat procedure. Apical HCM (ApHCM) has a better prognosis than SeHCM. However, the outcome of CA for AF in patients with ApHCM is unclear.

Clinical influence of early follow-up glycosylated hemoglobin levels on cardiovascular outcomes in diabetic patients with ST-segment elevation myocardial infarction after coronary reperfusion

ObjectiveRecent studies have shown continuous control of diabetes is important for favorable outcomes in patients with ST-segment elevation myocardial infarction (STEMI). This study aimed to evaluate the clinical influence of postprocedural glycosylated hemoglobin A1c (HbA1c) levels on major adverse cardiac events (MACE) in diabetic patients with STEMI after coronary reperfusion. Patients and methodsA total of 303 patients with diabetes and STEMI undergoing a primary percutaneous coronary intervention were enrolled in this study. All eligible patients were divided into the following three groups on the basis of follow-up HbA1c (FU-HbA1c) levels, which were measured at a median of 85 days after the procedure: optimal, FU-HbA1c<7%; suboptimal, 7%⩽FU-HbA1c<9%; and poor, FU-HbA1c≥9%. We analyzed the 12-month cumulative MACE, defined as mortality, nonfatal myocardial infarction, and revascularization. In addition, we investigated FU-HbA1c levels as a predictor of MACE. ResultsThe incidence rates of MACE differed significantly between groups (6.4 vs. 13.6 vs. 19.6%; P=0.048). Moreover, the risk was increased in each successive group (hazard ratio: 1.00 vs. 2.19 vs. 3.68; P=0.046). Each 1% increase in the FU-HbA1c level posed a 26.6% relative increased risk of MACE (P=0.031). The optimal cutoff value for FU-HbA1c in predicting MACE was 7.45%. ConclusionThis study showed that higher levels of early FU-HbA1c after reperfusion in diabetic patients with STEMI were associated with increased 12-month MACE, suggesting continuous serum glucose level control even after reperfusion is important for a better outcome. FU-HbA1c seems to be a useful marker for predicting clinical outcome.

Gender-related Difference in Clinical Outcome of the Patient with Atrial Fibrillation after Radiofrequency Catheter Ablation

Background and Objectives Previous studies provided controversial result about gender differences in the clinical outcome after radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF). We assessed pure difference after adjustment of referral bias. Methods The clinical outcomes including freedom from AF/atrial tachycardia (AT) recurrence after RFCA were compared between women and men in 1:1 confounding factor matching with age, AF type, periods since diagnosis (±12 months), and procedure era (±12 months). Subgroup analysis was performed in categories defined by AF type and age of 55 (mean menopausal age of Asian women). Results Total 1,875 patients with AF underwent 2,307 RFCA between January 1998 and May 2014 in a single center. Total 367 women (19.6%, 59±10 years) who had undergone first ablation were included. Women had larger left atrial diameter index (26±4 vs. 23±4 mm/m2; p<0.001) and higher peri-procedural complications (9.2% vs. 4.9%; p=0.030) compared to men. The freedom from AF/AT recurrence after RFCA was not different between both groups (71% vs. 76%; log-rank p=0.131, mean follow-up of 55 months). Women with non-paroxysmal AF (PAF) had significantly worse outcome (54% vs. 69%; p=0.014), especially in subgroup with age ≤55 (48% vs. 71%; p=0.010). In multivariate analysis, female gender was an independent predictor of recurrence in subgroup with non-PAF and age ≤55 (hazard ratio [HR], 2.539; 95% confidence interval [CI], 1.112–5.801; p=0.027). Conclusions The clinical outcome after RFCA was not different between both genders regardless of referral bias. However, the gender difference became evident in patients under 55 years with non-PAF.

The predictive value of echocardiography for chronic thromboembolic pulmonary hypertension after acute pulmonary embolism in Korea

BACKGROUND/AIMS Chronic thromboembolic pulmonary hypertension (CTEPH) is a life-threatening complication after acute pulmonary embolism (APE) and is associated with substantial morbidity and mortality. This study aimed to investigate the incidence of CTEPH after APE in Korea and to determine echocardiographic predictors of CTEPH. METHODS Among 381 patients with APE confirmed by chest computed tomography (CT) between January 2007 and July 2013, 246 consecutive patients with available echocardiographic data were enrolled in this study. CTEPH was defined as a persistent right ventricular systolic pressure (RVSP) greater than 35 mmHg on echocardiography during follow-up and persistent pulmonary embolism on the follow-up CT. RESULTS Fifteen patients (6.1%) had CTEPH. The rate of right ventricular (RV) dilatation (66.7% vs. 28.1%, p = 0.002) and the RVSP (75.5 mmHg vs. 39.0 mmHg, p < 0.001) were significantly higher in the CTEPH group. D-dimers, RV dilatation, RV hypertrophy, RVSP, and intermediate-risk APE were associated with the risk of CTEPH after APE (odds ratio [OR] 0.59, 5.11, 7.82, 1.06, and 4.86, respectively) on univariate analysis. RVSP remained as a significant predictor of CTEPH on multivariate analysis (OR, 1.056; 95% confidence interval, 1.006 to 1.109; p = 0.029). CONCLUSIONS This study showed that the incidence of CTEPH after APE in Korea was 6.1% and that initial RVSP by echocardiography was a strong prognostic factor for CTEPH.