Jidong Sung

Decreased Number and Impaired Angiogenic Function of Endothelial Progenitor Cells in Patients With Chronic Renal Failure

Objective—Increased risk of cardiovascular disease in patients with chronic renal failure (CRF) has been explained by accelerated atherosclerosis and impaired angiogenesis, in which endothelial progenitor cells (EPCs) may play key roles. We hypothesized that altered EPC biology may contribute to the pathophysiology of CRF. Methods and Results—EPCs were isolated from CRF patients on maintenance hemodialysis (n=44) and from a normal control group (n=30). CRF patients showed markedly decreased numbers of EPC (44.6%) and colonies (75.3%) when compared with the controls (P <0.001). These findings were corroborated by 30.5% decrease in EPC migratory function in response to vascular endothelial growth factor (VEGF) (P =0.040) and 48.8% decrease in EPC incorporation into human umbilical vein endothelial cells (HUVEC) (P <0.001). In addition, Framingham’s risk factor score of both CRF (r = −0.461, P =0.010) and normal group (r = −0.367, P =0.016) significantly correlated with the numbers of EPC. Indeed, the number of circulating EPC was significantly lower in CRF patients than in normal group under the same burden of risk factors (P <0.001). A significant correlation was also observed between dialysis dose (Kt/V) and EPC incorporation into HUVEC (r =0.427, P =0.004). Conclusions—EPC biology, which is critical for neovascularization and the maintenance of vascular function, is altered in CRF. Our data strongly suggest that dysfunction of circulating EPC has a role in the progression of cardiovascular disease in patients with CRF.

The effects of atorvastatin on the occurrence of postoperative atrial fibrillation after off-pump coronary artery bypass grafting surgery.

BACKGROUND Atrial fibrillation (AF) after coronary artery bypass graft (CABG) surgery is still the most common arrhythmic complication. This study evaluated whether pretreatment with atorvastatin protects against AF after off-pump CABG. METHODS One hundred twenty-four patients without a history of AF or previous statin use, who were scheduled to undergo elective off-pump CABG, were enrolled. Patients were randomized to control group (n = 62) or to atorvastatin group (n = 62) who were administered atorvastatin 20 mg/d for 3 days before the surgery. Primary outcome was the incidence of postoperative AF. Secondary outcomes were major adverse cardiac and cerebrovascular events, persistent AF at 1 month, and identification of the markers to predict inhospital postoperative AF. RESULTS The incidence of AF was significantly lower in the atorvastatin group than in the control group (13% vs 27%, P = .04). The incidence of major adverse cardiac and cerebrovascular events and persistent AF at 1 month was similar in comparisons between the groups. Postoperative peak N-terminal pro-brain natriuretic peptide levels were significantly higher in the patients with AF (P = .03). Multivariate analysis identified pretreatment with atorvastatin as an independent factor associated with a significant reduction in postoperative AF (odds ratio 0.34, P = .04). Higher postoperative peak N-terminus pro-B-type natriuretic peptide levels were associated with the development of postoperative AF (odds ratio 1.02 per 100 pg/mL, P = .03). CONCLUSIONS Pretreatment with atorvastatin significantly reduced the occurrence of postoperative AF after off-pump CABG.

Effects of Red Ginseng upon Vascular Endothelial Function in Patients with Essential Hypertension

This study is to estimate the effect of Korean red ginseng on vascular endothelial cell dysfunction in patients with hypertension. Seventeen patients with hypertension who were divided into ginseng-treated (7) and non-treated (10) groups and 10 normotensive subjects were included. To assess the function of the vascular endothelial cell, changes of forearm blood flow to infusion of acetylcholine, sodium nitroprusside and bradykinin in incremental doses were measured by venous occlusion plethysmography. In the ginseng-treated hypertensive group, forearm blood flows at the highest dose of acetylcholine and bradykinin were significantly higher than those of the non-treated hypertensive group and were not different from those of the control group. In the case of sodium nitroprusside infusion, no significant differences were observed between the control, non-treated and treated groups. In conclusion, Korean red ginseng can improve the vascular endothelial dysfunction in patients with hypertension possibly through increasing synthesis of nitric oxide.

A coronary heart disease prediction model: the Korean Heart Study

Objective The objectives of this study were to develop a coronary heart disease (CHD) risk model among the Korean Heart Study (KHS) population and compare it with the Framingham CHD risk score. Design A prospective cohort study within a national insurance system. Setting 18 health promotion centres nationwide between 1996 and 2001 in Korea. Participants 268 315 Koreans between the ages of 30 and 74 years without CHD at baseline. Outcome measure Non-fatal or fatal CHD events between 1997 and 2011. During an 11.6-year median follow-up, 2596 CHD events (1903 non-fatal and 693 fatal) occurred in the cohort. The optimal CHD model was created by adding high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol and triglycerides to the basic CHD model, evaluating using the area under the receiver operating characteristic curve (ROC) and continuous net reclassification index (NRI). Results The optimal CHD models for men and women included HDL-cholesterol (NRI=0.284) and triglycerides (NRI=0.207) from the basic CHD model, respectively. The discrimination using the CHD model in the Korean cohort was high: the areas under ROC were 0.764 (95% CI 0.752 to 0.774) for men and 0.815 (95% CI 0.795 to 0.835) for women. The Framingham risk function predicted 3–6 times as many CHD events than observed. Recalibration of the Framingham function using the mean values of risk factors and mean CHD incidence rates of the KHS cohort substantially improved the performance of the Framingham functions in the KHS cohort. Conclusions The present study provides the first evidence that the Framingham risk function overestimates the risk of CHD in the Korean population where CHD incidence is low. The Korean CHD risk model is well-calculated alternations which can be used to predict an individuals risk of CHD and provides a useful guide to identify the groups at high risk for CHD among Koreans.

Lung function, coronary artery calcification, and metabolic syndrome in 4905 Korean males

BACKGROUND Impaired lung function is an independent predictor of cardiovascular mortality. We assessed the relationships of lung function with insulin resistance (IR), metabolic syndrome (MetS), systemic inflammation and coronary artery calcification score (CACS) measured by computed tomography (CT) scan an indicator of coronary atherosclerosis. METHODS We identified 4905 adult male patients of the Health Promotion Center in Samsung Medical Center between March 2005 and February 2008 and retrospectively reviewed the following data for these patients: pulmonary function, CT-measured CACS, anthropometric measurement, fasting glucose, insulin, lipid profiles, serum C-reactive protein (CRP) and homeostatic model assessment (HOMA-IR). MetS was defined according to the AHA/NHLBI criteria. RESULTS When the subjects were divided into four groups according to quartiles of FVC or FEV(1) (% pred), serum CRP level, HOMA-IR, prevalence of MetS and CACS significantly increased as the FVC or FEV(1) (% pred) decreased. The odds ratios (ORs) for MetS in the lowest quartiles of FVC and FEV(1) (% pred) were 1.85 (95% CI, 1.49-2.30; p<0.001) and 1.47 (95% CI, 1.20-1.81; p<0.001) respectively. The ORs for the presence of coronary artery calcification in the lowest quartiles of FVC and FEV(1) (% pred) were 1.31 (95% CI, 1.09-1.58; p=0.004) and 1.22 (95% CI, 1.02-1.46; p=0.029) respectively. Obesity, CRP, HOMA-IR, and the presence of coronary artery calcium were independent risk predictors for impaired lung function. CONCLUSION Metabolic syndrome, insulin resistance, coronary atherosclerosis, and systemic inflammation are closely related to the impaired lung function.

Surgical strategies for non-functioning pancreatic neuroendocrine tumours.

The purpose of this study was to identify management strategies for non‐functioning pancreatic neuroendocrine tumours (NF‐PNETs) by analysis of surgical outcomes at a single institution.

Metabolic Syndrome Is Associated with Delayed Heart Rate Recovery after Exercise

Heart rate (HR) recovery after exercise is a function of vagal reactivation, and its impairment is a predictor of overall mortality and adverse cardiovascular events. While metabolic syndrome is associated with sympathetic overactivity, little is known about the relationship between metabolic syndrome and HR recovery. A symptom-limited exercise stress test in healthy subjects (n=1,434) was used to evaluate HR recovery. Metabolic syndrome was defined according to the National Cholesterol Education Programs Adult Treatment Panel III (NCEP ATP-III) criteria. Seventeen percent of subjects had ≥3 criteria for metabolic syndrome. HR recovery was lower in men than women and in smokers than nonsmokers. The subject with metabolic syndrome (vs. without) showed lower HR recovery (10.3±11.6 vs. 13.6±9.7 per minute) and higher resting HR (64.3±10.3 vs. 61.6±9.1 per minute). HR recovery correlated inversely to age (r=-0.25, p<0.0001), but not to resting HR or maximal oxygen uptake. Delayed HR recovery was associated with metabolic syndrome after an adjustment for age, sex, resting HR and smoking (p<0.01). Metabolic syndrome is associated with impaired vagal reactivation. Adverse cardiovascular outcomes associated with metabolic syndrome may be mediated by the failure of vagal reactivation in addition to sympathetic overactivity.

Plasma transforming growth factor β1 as a biochemical marker to predict the persistence of atrial fibrillation after the surgical maze procedure

OBJECTIVES The Cox maze procedure was developed as a surgical treatment for atrial fibrillation. However, atrial fibrillation recurs in some patients, and atrial remodeling in the form of fibrosis can lead to perpetuation of atrial fibrillation. To identify the predictor of the persistence of atrial fibrillation after the maze procedure using cryoablation, we evaluated the preoperative plasma transforming growth factor beta1. We also examined the correlations between plasma transforming growth factor beta1 levels and the degree of atrial fibrosis. METHODS Preoperative plasma transforming growth factor beta1 levels were measured in 86 consecutive patients (age, 54 +/- 12 years) who underwent both the open heart operation for valvular heart disease and the surgical maze procedure with cryoablation for persistent atrial fibrillation. We measured the degree of fibrosis from the tissue of the left atrium. RESULTS At 1 years follow-up, 10 of 86 patients had persistent atrial fibrillation. Patients with persistent atrial fibrillation had higher preoperative plasma transforming growth factor beta1 levels than the patients with sinus rhythm (0.44 +/- 0.29 vs 0.32 +/- 0.15 ng/mL, P = .03). Patients with persistent atrial fibrillation had higher mRNA expressions of collagen III and lower mRNA expressions of atrial natriuretic peptide than those with sinus rhythm, and the plasma transforming growth factor beta1 levels correlated with the degree of fibrosis in the left atrium (r = 0.497, P = .022). Multiple logistic regression analysis revealed that plasma transforming growth factor beta1 levels were independently associated with the postoperative persistence of atrial fibrillation at 1 years follow-up. CONCLUSIONS Preoperative plasma transforming growth factor beta1 levels could be used to predict the persistence of atrial fibrillation at 1 years follow-up after the surgical maze procedure by using cryoablation. Preoperative plasma transforming growth factor beta1 levels were correlated with the degree of fibrosis in the left atria of patients with mitral valvular heart disease.

Right ventricular fat infiltration in asymptomatic subjects: observations from ECG-gated 16-slice multidetector CT.

Objective: To analyze the computed tomography (CT) findings of fatty replacement in the right ventricle (RV) of asymptomatic subjects and to correlate the CT findings with electrocardiogram (ECG) abnormalities. Methods: This prospective study included 996 subjects who underwent ECG-gated 16-slice CT for determination of coronary calcium scores. The CT findings were analyzed in terms of location, pattern, and degree of RV fat infiltration, along with the shape and dimension of RV. The RV fat was regarded present when a region showed less than or equal to −30 Hounsfield units as revealed by CT. Results: Computed tomography features suggestive of RV fat were found in 169 subjects (17%; 136 men and 33 women; mean age, 56.3 years). The most frequent location of fat was the basal superior wall (93%); next was the middle superior wall (72%); and then, the RV outflow tract (44%). Subjects with moderate to severe involvement were older than those with mild involvement (P = 0.012). In 3 subjects, the RV wall thickening with fat was more than 5 mm. Angular deformity and undulating appearance of the RV also occurred in 25 (15%) and 20 subjects (12%), respectively. However, these were not patients with ECG findings positive for arrhythmogenic RV dysplasia. Conclusions: Asymptomatic subjects may have fat in RV on CT. However, these subjects show no RV dysfunction or significant ECG-abnormalities consistent with the diagnosis of arrhythmogenic RV dysplasia.

The Korean Heart Study: rationale, objectives, protocol, and preliminary results for a new prospective cohort study of 430,920 men and women.

Background To describe the rationale, objectives, protocol, and preliminary results for a new prospective cohort study of cardiovascular disease (CVD) risk factors in South Korea. Methods Study members were recruited from participants in routine health assessments at health promotion centres across South Korea. Established and emerging CVD risk factors were measured. Eighteen centres holding electronic health records agreed to linkage of participants’ records to future health insurance claims for monitoring of disease events. The recruitment of 430,920 participants (266,782 men, 164,138 women), aged 30–74 years, provides broad geographical reach across South Korea. Results Risk factor prevalence was more favourable in women than men, and, in general, in the younger rather than older study members. There was also close similarity between the characteristics of the present sample and the Korean National Health and Nutrition Examination Survey. The expected associations between risk factors and both CVD and death were also apparent. Conclusions Data from the present sample, based on data linkage, show close agreement with South Korea-wide surveys (for risk factor prevalence) and the extant literature (for risk factor associations). These findings gives confidence in future results anticipated from this cohort study of east Asians – a group that has been traditionally under-researched.