Sung Woo Kwon

Coronary Artery Calcium Scoring Does Not Add Prognostic Value to Standard 64-Section CT Angiography Protocol in Low-Risk Patients Suspected of Having Coronary Artery Disease

PURPOSE To evaluate the prognostic outcome of cardiac computed tomography (CT) for prediction of major adverse cardiac events (MACEs) in low-risk patients suspected of having coronary artery disease (CAD) and to explore the differential prognostic values of coronary artery calcium (CAC) scoring and coronary CT angiography. MATERIALS AND METHODS Institutional review committee approval and informed consent were obtained. In 4338 patients who underwent 64-section CT for evaluation of suspected CAD, both CAC scoring and CT angiography were concurrently performed by using standard scanning protocols. Follow-up clinical outcome data regarding composite MACEs were procured. Multivariable Cox proportional hazards models were developed to predict MACEs. Risk-adjusted models incorporated traditional risk factors for CAC scoring and coronary CT angiography. RESULTS During the mean follow-up of 828 days ± 380, there were 105 MACEs, for an event rate of 3%. The presence of obstructive CAD at coronary CT angiography had independent prognostic value, which escalated according to the number of stenosed vessels (P < .001). In the receiver operating characteristic curve (ROC) analysis, the superiority of coronary CT angiography to CAC scoring was demonstrated by a significantly greater area under the ROC curve (AUC) (0.892 vs 0.810, P < .001), whereas no significant incremental value for the addition of CAC scoring to coronary CT angiography was established (AUC = 0.892 for coronary CT angiography alone vs 0.902 with addition of CAC scoring, P = .198). CONCLUSION Coronary CT angiography is better than CAC scoring in predicting MACEs in low-risk patients suspected of having CAD. Furthermore, the current standard multisection CT protocol (coronary CT angiography combined with CAC scoring) has no incremental prognostic value compared with coronary CT angiography alone. Therefore, in terms of determining prognosis, CAC scoring may no longer need to be incorporated in the cardiac CT protocol in this population.

Lipoprotein(a) and LDL Particle Size Are Related to the Severity of Coronary Artery Disease

Background: The pathophysiological role and metabolic pathway of Lp(a) have not been clearly defined. An association between Lp(a) and oxidative low-density lipoprotein (LDL) were recently reported. And small dense LDL (sd-LDL) were associated with circulating malondialdehyde-modified LDL. We investigated the relationships between serum Lp(a) level and LDL particle size in coronary artery disease (CAD) patients. Further, we investigated the relationships of sd-LDL and Lp(a) with the extent and severity of CAD. Methods: A total of 490 patients (mean: 60.5 ± 11.5 years old) who underwent coronary angiography to evaluate chest pain were investigated. Patients were classified into two groups, a CAD group (n = 256), who had significant stenosis observed by coronary angiogram, and a control group (n = 234), who had normal, or minimal coronary arteries. CAD severity was measured by Gensini scores. The distribution of the LDL subfraction was analyzed using a Quantimetrix Lipoprint LDL System. Results: The serum Lp(a) concentration was correlated with the fraction of sd-LDL (r = 0.193, p < 0.001) and mean LDL size (r = 0.160, p = 0.003). The Lp(a) level and mean LDL particle size were significantly correlated with a high Gensini score. LDL particle size in the CAD group was smaller than in the control group (26.74 ± 0.64 vs. 26.43 ± 0.93 nm, p < 0.001). The Gensini score was significantly higher in small LDL with high Lp(a) level groups. Conclusion: The positive correlation of the level of Lp(a) and sd-LDL fraction were demonstrated. The mechanism of this association is not clearly defined; we can suggest that it may stem from the individual atherogenic condition that linked to increased oxidative stress. Both increased Lp(a) and sd-LDL fraction were correlated with the severity of CAD.

Significance of Small Dense Low-Density Lipoprotein as a Risk Factor for Coronary Artery Disease and Acute Coronary Syndrome

Small dense LDL (sd-LDL) has recently emerged as an important coronary artery disease (CAD) risk factor. This study was performed to investigate how LDL particle size is related to CAD and acute coronary syndrome (ACS). Blood samples were collected from 504 patients that underwent coronary angiography to evaluate chest pain. The LDL particle size of these samples was measured. The mean LDL particle size was smaller in patients with angiographically proven CAD than in the controls (26.41 ± 0.95 vs 26.73 ± 0.64 nm, p < 0.001), and was negatively correlated with the Framingham risk score (r = -0.121, p = 0.007). Patients with more extensive CAD had smaller LDL particles. LDL particle size was also smaller in patients with acute coronary syndrome as compared to non-ACS patients (26.09 ± 1.42 vs 26.54 ± 0.63 nm, p = 0.011). These results suggest that sd-LDL is independently associated with the incidence and extent of CAD, and can be a risk factor for the development of ACS in the Korean population.

Qualitative assessment of neointimal tissue after drug-eluting stent implantation: Comparison between follow-up optical coherence tomography and intravascular ultrasound

BACKGROUND Characterization of neointimal tissue is essential to understand the pathophysiology of in-stent restenosis after drug-eluting stent (DES) implantation. We compared the morphological characteristics of neointimal tissue as assessed by optical coherence tomography (OCT) and intravascular ultrasound (IVUS) in patients treated with DES. METHODS A total of 243 patients (250 lesions) underwent follow-up OCT and IVUS after DES implantation. RESULTS Mean time interval from DES implantation to follow-up OCT/IVUS was 12.0 ± 9.3 (range 2.8-68.5) months. Percent neointimal hyperplasia (NIH) cross-sectional area (CSA) was calculated as (NIH CSA/stent CSA) × 100 for receiver-operating characteristic analysis of NIH detection by IVUS; the optimal cutoff value of percent NIH CSA was 14.7%, as determined by OCT (sensitivity 0.887, specificity 0.790). Neointimal hyperplasia was detected by both OCT and IVUS in 121 of 250 lesions and categorized as homogenous (OCT n = 74, IVUS n = 107), heterogeneous (OCT n = 34, IVUS n = 4), or layered (OCT n = 13, IVUS n = 10). Of the 121 NIH lesions, nonhomogenous NIH was detected in 14 (11.6%) by IVUS and 47 (38.8%) by OCT. Optical coherence tomography and IVUS assessments of NIH morphology showed a moderate correlation (P < .001, r = 0.455); however, assessments differed in 37 (30.6%) of 121 lesions. CONCLUSION Optical coherence tomography-assessed NIH morphology might be different from that by IVUS in about 30% of the lesions that were treated with DES implantation.

Serum Levels of Advanced Glycation End Products Are Associated with In-Stent Restenosis in Diabetic Patients

The formation of advanced glycation end products (AGEs), in various tissues has been known to enhance immunoinflammatory reactions and local oxidant stresses in long standing diabetes. Recently, AGEs have been reported to play a role in neointimal formation in animal models of arterial injury. We attempted to determine whether the serum levels of AGEs are associated with coronary restenosis in diabetic patients. Blood samples were collected from diabetic patients with coronary artery disease undergoing stent implantation and the serum levels of AGEs were analyzed by the fluorescent intensity method. The development of in-stent restenosis (ISR) was evaluated by a 6-month follow-up coronary angiography. A total of 263 target lesions were evaluated, in 203 patients. The ISR rate in the high-AGE (>170 U/ml) group (40.1%) was significantly higher than in the low-AGE group (≤170 U/ml) (19.6%) (p<0.001). Furthermore, multivariate analysis revealed that a high level of serum AGEs is an independent risk factor for the development of ISR (odds ratio, 2.659; 95% CI, 1.431-4.940; p=0.002). The serum levels of AGEs constitute an excellent predictive factor for ISR, and should be one of the guidelines for medical therapy and interventional strategy to prevent ISR in diabetic patients.

Randomised trial to compare a protective effect of Clopidogrel Versus TIcagrelor on coronary Microvascular injury in ST-segment Elevation myocardial infarction (CV-TIME trial).

AIMS Ticagrelor has shown greater, more rapid and more consistent platelet inhibition than clopidogrel. However, the superiority of ticagrelor for preventing ischaemic damage in STEMI patients has not been proven. The aim of this trial was to assess whether ticagrelor is superior to clopidogrel in preventing microvascular injury in ST-elevation myocardial infarction (STEMI). METHODS AND RESULTS Patients with STEMI underwent prospective random assignment to receive a loading dose (LD) of clopidogrel 600 mg or ticagrelor 180 mg (1:1 ratio) before primary percutaneous coronary intervention (PCI). As the primary endpoint, the index of microcirculatory resistance (IMR) was measured immediately after primary PCI. The secondary endpoint was the infarct size estimated from the wall motion score index (WMSI). A total of 76 patients were enrolled (clopidogrel group=38, ticagrelor group=38). The IMR in the ticagrelor group was significantly lower than that in the clopidogrel group (22.2±18.0 vs. 34.4±18.8 U, p=0.005). Cardiac enzymes were less elevated in the ticagrelor group than in the clopidogrel group (CK peak; 2,651±1,710 vs. 3,139±2,698 ng/ml, p=0.06). Infarct size, estimated by WMSI, was not different between the ticagrelor and clopidogrel groups at baseline (1.55±0.30 vs. 1.61±0.29, p=0.41) or after three months (1.42±0.33 vs. 1.47±0.33, p=0.57). CONCLUSIONS In patients with STEMI treated by primary PCI, a 180 mg LD of ticagrelor might be more effective in reducing microvascular injury than a 600 mg LD of clopidogrel, as demonstrated by IMR immediately after primary PCI.

Comprehensive assessment of microcirculation after primary percutaneous intervention in ST-segment elevation myocardial infarction: insight from thermodilution-derived index of microcirculatory resistance and coronary flow reserve

ObjectivesA pathophysiological mechanism of microvascular dysfunction in ST-segment elevation myocardial infarction (STEMI) is multifactorial; thus, multiple modalities were needed to precisely evaluate a microcirculation. MethodsWe complementarily assessed microcirculation in STEMI by the index of microcirculatory resistance (IMR) and coronary flow reserve (CFR) immediately after a primary percutaneous intervention in 89 STEMI patients. Cardiovascular and cerebrovascular events (MACCE) including cardiovascular death, target vessel failure, heart failure, and stroke were assessed during a mean follow-up period of 3.0 years. ResultsThe microcirculation of enrolled patients was classified into four groups using cutoff CFR and IMR values (CFR>2 and mean IMR): group-1 (n=23, CFR>2 and IMR⩽27); group-2 (n=31, CFR⩽2 and IMR⩽27); group-3 (n=9, CFR>2 and IMR>27); and group-4 (n=26, CFR<2 and IMR>27). On echocardiography 3 months later, improvement in the wall motion score index was shown in group-1 (P<0.01), group-2 (P<0.01), and group-3 (P=0.04), whereas group-4 did not show improvement in wall motion score index (P=0.06). During clinical follow-up, there were no MACCE in group-1 and the patients in group-2 and group-3 showed significantly lower MACCE compared with group-4 (group-1=0%, group-2, and group-3=10%, group-4=23.1%, P=0.04). ConclusionComplimentary assessment of microcirculation by the IMR and CFR may be useful to evaluate myocardial viability and the long-term prognosis of STEMI patients.

Synephrine-containing dietary supplement precipitating apical ballooning syndrome in a young female

Apical ballooning syndrome (ABS) is a unique reversible cardiomyopathy that is frequently precipitated by emotional or physical stress. In addition, the few drugs reported to precipitate ABS were either illegal or strictly controlled for medical use. This paper reports a case of ABS precipitated by a dietary supplement. Our case accentuates the potential risk of dietary supplements containing synephrine, which is uncontrolled and available to the general public. Therefore, the Korea Food and Drug Administration should regulate these dietary supplements, and warn healthcare workers and the general public of the potential hazards of the indiscriminate abuse of dietary supplements.

Prognostic significance of elevated lipoprotein(a) in coronary artery revascularization patients

BACKGROUND Although lipoprotein(a) [Lp(a)] has been considered a cardiovascular risk factor for many years, there is a paucity of data in regard to the potential risk of elevated Lp(a) in symptomatic patients with CAD. Therefore, we sought to evaluate whether elevated Lp(a) is associated with worse outcome in symptomatic patients with coronary artery disease (CAD), and to clarify the prognostic value of Lp(a) in the era of coronary artery revascularization. METHODS 6252 consecutive subjects (59.2% male, mean age 61.2 ± 11.2 years) suspected of having CAD underwent coronary angiography. Laboratory values for lipid parameters including Lp(a) were obtained on the day of coronary angiography. Baseline risk factors, coronary angiographic findings, length of follow-up, and major adverse cardiovascular events (MACE), including cardiac death and non-fatal myocardial infarction were recorded. RESULTS Over a mean follow-up period of 3.1 ± 2.2 years, there were 100 MACE (56 cardiac deaths and 44 non-fatal myocardial infarctions), with an event rate of 1.6%. In multivariate Cox regression analysis, elevated Lp(a) was a significant predictor of MACE [hazard ratio 1.773 (95% confidence interval 1.194-2.634, p=0.005)], and the addition of this factor to the model significantly increased the global х(2) value over traditional risk factors and CAD (from 79.1 to 88.7, p=0.003). CONCLUSIONS Elevated Lp(a) is an independent prognostic risk factor for cardiovascular events, and moreover, has incremental prognostic value in symptomatic patients with coronary artery revascularization.

Outcomes of Cardiac Involvement in Patients with Late-Stage Duchenne Muscular Dystrophy under Management in the Pulmonary Rehabilitation Center of a Tertiary Referral Hospital

Objectives: The purpose of this study was to investigate the clinical outcome as well as the sequential changes of cardiac function in late-stage Duchenne muscular dystrophy (DMD) patients by 2-dimensional echocardiography. Methods: A total of 31 individuals (initial age: 21.6 ± 5.0 years, range: 15–35 years) with late-stage DMD (Swinyard-Deaver’s stage 7 or 8) were enrolled. All of these patients had respiratory insufficiency and were on ventilator support. Sequential echocardiographic data were collected over at least 3 years. Repeated measures analysis of variance was used to compare changes in left ventricular ejection fraction (LVEF) over time. Results: The sequential change in the mean LVEF showed no significant differences with initial, 1-, 2-, and 3-year follow-up LVEFs which were 42.2, 42.9, 43.8 and 42.6%, respectively (p = 0.320). In terms of the clinical outcome, all but 1 patient survived during the follow-up period of 46.5 ± 9.1 months. Conclusions: The cardiac function in late-stage DMD patients showed a stabilization of LVEF on adequate ventilatory support and optimal cardiac medication therapy until their mid-30s. In addition, considering the favorable clinical outcome in our study, the process of cardiac involvement in late-stage DMD may demonstrate that in some patients it is nonprogressive.