• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1660-1664
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• 2008

Extra-corporeal Life Support System (ECLS) is the device used in emergency cases to substitute a extracorporeal circulation in open heart surgery, cardiac arrest or in acute cardiopulmonary failure. To obtain the effect of counter-pulsation on hemodynamic response in the ECLS quantitatively, we developed cardiovascular model which consists of 12 compartment model of heldt et al. and 3 compartment model of Schreiner et al. based on windkessel approximation. We compared coronary perfusion, arterial pulse pressure, cardiac output, and left ventricular pressure-volume diagram according to flow configuration such as counter-pulsation, copulsation, and continous flow. When counter-pulsation was applied, 5% higher coronary perfusion, 26% lower pulse pressure, and 2% higher cardiac output than copulsation condition were calculated. We conclude that counter-pulsation configuration in the ECLS is hemodynamically more stable than copulsation and influences the positive effect to recover ventricles.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.4
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• pp.274-283
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• 2005

Coronary Perfusion Pressure(CPP) is known for the most important parameter related to the Return of Spontaneous Circulation (ROSC), however, clinically measuring CPP is difficult either invasive or non-invaisive method. En this paper, we analyze the correlation between the extracted parameter from VF ECG wave and the CPP with the statistical method, and predict CPP value using the extracted parameters within significance level. the extracted parameters are median frequency(MF), peak frequency(PF), average segment amplitude(ASA), MSA(maximum segment amplitude), Two parameters, MF, and ASA are selected in order to predict CPP value with general regression neural network, and then we evaluated the agreement statistics between the simulated CPP and the measured CPP. In conclusion, the mean and variance of the difference between the simulated CPP and the measured CPP are 8.9716±1.3526 mmHg, and standard deviation 6.4815 mmHg with one hundred-times training and test results. the simulated CPP and the measured CPP are agreed with the overall accuracy $90.68\%$ and kappa coefficient $81.14\%$ as a discriminant parameter of ROSC.

• Journal of Chest Surgery
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• v.36 no.10
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• pp.772-775
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• 2003

Moyamoya disease is an unusual cerebrovascular disorder characterized by occlusive intimal dysplasia of the distal internal carotid and proximal cerebral arteries, but the etiology remains unclear. Angiographic characteristics include bilateral stenosis or occlusion of the terminal portions of the intracranial internal carotid arteries and bilateral development of fine collateral vessels at the base of the brain known as ‘Moyamoya vessels’. Cardiac surgery using cardiopulmonary bypass due to coronary artery disease and others among patients with moyamoya disease is very rare, and cardiac surgery for such patients has a potential risk of intraoperative and perioperative brain ischemia. We successfully treated a patient who underwent artrial septal defect closure and coronary artery bypass graft using the cardiopulmonary bypass, so we report this case with a brief literature review.

• Journal of Chest Surgery
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• v.12 no.3
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• pp.207-214
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• 1979

This 3-year-old girl was observed frequent exertional dyspnea and cyanosis at crying since birth. She was not premature baby and delivered at full term normally. On physical examination, she was underdeveloped-body weight 13.5 kg, height 99 cm.- and cyanotic. There was severe clubbing on fingers. There was grade II/VI ejection systolic murmur on left lateral border of the sternum. The preoperative examinations [EKG, echocardiogram, cardiac catheterization and biventriculogram] showed that complicated T.G.A. combined vena cava[S.D.D.]. Preoperatively, we decided the corrective surgery of Rastelli operation using a. pulmonary valved conduit. The operation was performed under total circulatory arrest using deep profound hypothermia combining with extracorporeal circulation. On operation, the anatomy of the heart showed that, 1. The subaortic conus was seen and subaortic muscles were hypertrophied. 2. The VSD[type II], behind the subaortic conus-about 1 cm. in diameter, was visible only through LV cavity and, 3. The pulmonary valve ring was hypoplastic and pulmonary valvular stenosis was seen also. The subpulmonic area [LV outflow tract] was obstructed with hypertrophied muscle and mitral valve. 4. Left superior vena cava was drained to RA via coronary sinus. 5. LAD coronary artery was originated from right coronary artery and ran anterior to the pulmonary artery. According to above anatomy, we performed the VSD closure with Teflon patch, and Mustard operation combined with LV-to-pulmonary artery bypass graft using the valve contained [Hancock 16 mm] conduit. Postoperatively, adequate blood pressure could be maintained under the state of using inotropic agent [epinephrine]. On the second postoperative day, the patient died of cardiac arrest due to low cardiac output syndrome, acute renal failure and pulmonary edema.

• Korean Circulation Journal
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• v.52 no.11
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• pp.814-825
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• 2022

Background and Objectives: Real-world trends in the utility and type of gatekeeping studies in invasive coronary angiography (ICA) requires further investigation. Methods: We identified outpatients who underwent noninvasive cardiac tests or directly ICA for suspected coronary artery disease (CAD) from the nationwide Korea Health Insurance Review and Assessment Service-National Patient Sample database between 2012 and 2018. Results: Among 71,401 patients, the percentage of patients who were evaluated for suspected CAD was 34.7% for treadmill test (TMT), 4.2% for single-photon emission computed tomography (SPECT), 24.2% for coronary computed tomography angiography (CCTA), 1.6% for multiple gatekeepers, and 32.3% for directly ICA without noninvasive studies. The proportion of CCTA as a gatekeeper showed linear increase, (18.6% in 2012 and 28.8% in 2018; p<0.001), while those of TMT, SPECT, and direct ICA have decreased (p<0.001, p=0.03, and p<0.001, respectively). The overall incidence of downstream ICA after gatekeeper was 13.8% (6,662/48,346), and SPECT showed higher ICA rate in pairwise comparison with TMT and CCTA (p<0.001). Patients who performed gatekeepers before ICA showed higher rate of subsequent PCI (34.7% vs. 32.3%; p<0.001) and CABG (3.5% vs. 1.0%; p<0.001), compared to those who directly underwent ICA, and CCTA was associated with higher revascularization rate after ICA in pairwise comparison with TMT and SPECT (p<0.001). Conclusions: Nationwide database demonstrated that CCTA is utilized increasingly as a gatekeeper for ICA and is associated with high revascularization rate after ICA in outpatients with suspected CAD.

• Korean Circulation Journal
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• v.52 no.4
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• pp.304-319
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• 2022

Background and Objectives: De-escalation of dual-antiplatelet therapy through dose reduction of prasugrel improved net adverse clinical events (NACEs) after acute coronary syndrome (ACS), mainly through the reduction of bleeding without an increase in ischemic outcomes. Whether the benefits of de-escalation are sustained in highly thrombotic conditions such as ST-elevation myocardial infarction (STEMI) is unknown. We aimed to assess the efficacy and safety of de-escalation therapy in patients with STEMI or non-ST-segment elevation ACS (NSTE-ACS). Methods: This is a pre-specified subgroup analysis of the HOST-REDUCE-POLYTECH-ACS trial. ACS patients were randomized to prasugrel de-escalation (5 mg daily) or conventional dose (10 mg daily) at 1-month post-percutaneous coronary intervention. The primary endpoint was a NACE, defined as a composite of all-cause death, non-fatal myocardial infarction, stent thrombosis, clinically driven revascularization, stroke, and bleeding events of grade ≥2 Bleeding Academic Research Consortium (BARC) criteria at 1 year. Results: Among 2,338 patients included in the randomization, 326 patients were diagnosed with STEMI. In patients with NSTE-ACS, the risk of the primary endpoint was significantly reduced with de-escalation (hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.48-0.89; p=0.006 for de-escalation vs. conventional), mainly driven by a reduced bleeding. However, in those with STEMI, there was no difference in the occurrence of the primary outcome (HR, 1.04; 95% CI, 0.48-2.26; p=0.915; p for interaction=0.271). Conclusions: Prasugrel dose de-escalation reduced the rate of NACE and bleeding, without increasing the rate of ischemic events in NSTE-ACS patients but not in STEMI patients.

• Korean Circulation Journal
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• v.52 no.2
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• pp.150-161
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• 2022

Background and Objectives: Studies evaluating the nature of ischemic burden of chronic total occlusion (CTO) vessels are still lacking. Methods: A total of 165 patients with single vessel CTO >2.5 mm in an epicardial coronary artery who underwent single photon emission computed tomography (SPECT) were enrolled in the study. Ischemic burden was calculated with the use of semi-quantitative SPECT analysis, and was defined as the summed difference score (SDS) divided by the maximal limit of the score (=SDS/68). Results: The mean age of the participants was 59.5 years and the CTO of the left anterior descending coronary artery (LAD), left circumplex coronary artery (LCX), and right coronary artery (RCA) accounted for 93 (56.4%), 18 (10.9%), and 54 (32.7%) patients, respectively. The median ischemic burden of the total population was 8.8%, and it was highest in the LAD CTO (10.3%) compared with the LCX (5.9%) and RCA CTO (5.9%, p<0.001). High-ischemic burden (ischemic burden >10%) was observed in 66 patients (40.0%), and in 47 patients (50.5%) of the LAD CTO. Ischemic burden was different according to the CTO location only in LAD CTO. The statistically significant predictors for high-ischemic burden were hypertension, baseline ejection fraction >45%, LAD CTO, proximal CTO location, and de novo CTO. Japanese-CTO score and Rentrop scale collateral grade were not associated with high-ischemic burden. Conclusions: Only 40% of patients with single vessel CTO had ischemic burden >10%. For CTO vessels, measurement of ischemic burden using SPECT prior to revascularization may be helpful in identifying beneficial subjects.

• Korean Circulation Journal
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• v.52 no.1
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• pp.47-59
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• 2022

Background and Objectives: The influence of pre-intervention coronary physiologic status on outcomes post percutaneous coronary intervention (PCI) is not well known. We sought to investigate the prognostic implications of pre-PCI fractional flow reserve (FFR) combined with post-PCI FFR. Methods: A total of 1,479 PCI patients with pre-and post-PCI FFR data were analyzed. The patients were classified according to the median values of pre-PCI FFR (0.71) and post-PCI FFR (0.88). The primary outcome was target vessel failure (TVF) at 2 years. Results: The risk of TVF was higher in the low pre-PCI FFR group than in the high pre-PCI FFR group (hazard ratio, 1.82; 95% confidence interval, 1.15-2.87; p=0.011). In 4 group comparisons, the cumulative incidences of TVF at 2 years were 3.8%, 4.1%, 4.8%, and 10.2% in the high pre-/high post-, low pre-/high post-, high pre-/low post-, and low pre-/low post-PCI FFR groups, respectively. The risk of TVF was the highest in the low pre-/low post-PCI FFR group among the groups (p values for comparisons <0.05). In addition, the high pre-/low post-PCI FFR group presented a comparable risk of TVF with the high post-PCI FFR groups (p values for comparison >0.05). When the prognostic value of the post-PCI FFR was evaluated according to the pre-PCI FFR, the risk of TVF significantly decreased with an increase in post-PCI FFR in the low pre-PCI FFR group, but not in the high pre-PCI FFR group. Conclusions: Pre-PCI FFR was associated with clinical outcomes after PCI, and the prognostic value of post-PCI FFR differed according to the pre-PCI FFR.

• Korean Circulation Journal
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• v.52 no.7
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• pp.544-555
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• 2022

Background and Objectives: The outcome benefits of β-blockers in chronic coronary artery disease (CAD) have not been fully assessed. We evaluated the prognostic impact of β-blockers on patients with chronic CAD after percutaneous coronary intervention (PCI). Methods: A total of 3,075 patients with chronic CAD were included from the Grand Drug-Eluting Stent registry. We analyzed β-blocker prescriptions, including doses and types, in each patient at 3-month intervals from discharge. After propensity score matching, 1,170 pairs of patients (β-blockers vs. no β-blockers) were derived. Primary outcome was defined as a composite endpoint of all-cause death and myocardial infarction (MI). We further analyzed the outcome benefits of different doses (low-, medium-, and high-dose) and types (conventional or vasodilating) of β-blockers. Results: During a median (interquartile range) follow-up of 3.1 (3.0-3.1) years, 134 (5.7%) patients experienced primary outcome. Overall, β-blockers demonstrated no significant benefit in primary outcome (hazard ratio [HR], 0.88; 95% confidence interval [CI], 0.63-1.24), all-cause death (HR, 0.87; 95% CI, 0.60-1.25), and MI (HR, 1.25; 95% CI, 0.49-3.15). In subgroup analysis, β-blockers were associated with a lower risk of all-cause death in patients with previous MI and/or revascularization (HR, 0.38; 95% CI, 0.14-0.99) (p for interaction=0.045). No significant associations were found for the clinical outcomes with different doses and types of β-blockers. Conclusions: Overall, β-blocker therapy was not associated with better clinical outcomes in patients with chronic CAD undergoing PCI. Limited mortality benefit of β-blockers may exist for patients with previous MI and/or revascularization.

• Journal of Medicine and Life Science
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• v.15 no.2
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• pp.108-111
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• 2018

Extra-corporeal membrane oxygenation (ECMO) has the potential to rescue patients in cardiac arrest or respiratory failure. ECMO has two systems such as veno-arterial and veno-venous circulation. In cardiac arrest resulting from acute myocardial infarction, veno-arterial ECMO is mandatory for systemic circulation and oxygenation. A 75-year old female patient underwent primary coronary intervention for acute myocardial infarction. Despite successful revascularization, recurrent ventricular tachycardia and heart failure were progressing. We performed a veno-arterial ECMO through the femoral artery and vein, then the patient seemed to be stable clinically. However, laboratory studies, echocardiography, and vital signs indicated multi-organ failure and decreasing cardiac function. We found out an error that we performed veno-venous ECMO instead of veno-arterial ECMO. We added a femoral artery cannula and exchange the circuit system to veno-arterial ECMO. While the systemic circulation seemed to be recovered, the left ventricular function was decreased persistently. A hypovolemia resulting from pulmonary hemorrhage was occurred, which lead to ECMO failure. The patient died of cardiac arrest and multi-organ failure 23 hours after ECMO. Because the color of arterial and venous circuits represent the position and efficacy of ECMO, if unexpected or abnormal circuit colors are detected, prompt and aggressive evaluation for ECMO function is mandatory.