Left Ventricular Global Longitudinal Strain as a Predictor for Left Ventricular Reverse Remodeling in Dilated Cardiomyopathy

BACKGROUND A considerable number of patients with dilated cardiomyopathy (DCM) experience left ventricular reverse remodeling (LVRR). LV global longitudinal strain (LV GLS) offers sensitive and reproducible measurement of myocardial dysfunction. The authors sought to evaluate whether LV GLS at the time of diagnosis may predict LVRR in DCM patients with sinus rhythm and investigate its prognostic role in long-term follow-up in this population. METHODS We enrolled 160 DCM patients with sinus rhythm who had been initially diagnosed, evaluated, and followed at our institute. We analyzed their medical records and echocardiographic data. RESULTS During the mean follow-up duration of 37.3 ± 21.7 months, LVRR occurred in 28% of patients (n = 45). The initial LV ejection fraction (LVEF) of patients who recovered LV function was 26.1 ± 7.9%, which was not significantly different from the value of 27.1 ± 7.4% (p = 0.49) in those who did not recover. There was a moderate and highly significant correlation between baseline LV GLS (−%) and follow-up LVEF (r = 0.717; p < 0.001). Using multivariate Cox analysis, LV GLS (hazard ratio: 1.474, 95% confidence interval: 1.170-1.856; p = 0.001) was an independent predictor of LVRR. CONCLUSIONS We demonstrated that LV GLS was an independent predictor for LVRR and the optimal cut-off point of LV GLS for LVRR was −10% in DCM patients with sinus rhythm. There was a significant correlation between baseline LV GLS and follow-up LVEF.ope

Comparison of the improvement of flow-mediated dilatation in patients with acute coronary syndrome versus stable angina after six-month cardiac rehabilitation

Background: We investigated whether the improvement in endothelial function, measured using flow-mediated dilatation (FMD), an important predictor of cardiovascular outcomes, was comparable in acute coronary syndrome (ACS) versus stable angina patients after percutaneous coronary intervention (PCI) and a six-month cardiac rehabilitation (CR) programme. Methods: We analysed the results from 119 patients who completed a six-month CR programme after successful PCI for stable angina (n = 50) and ACS (n = 69). Results: After six months of CR, the results of FMD were significantly improved in both groups. There were no significant between-group differences in the FMD results at the six-month follow up. Conclusions: After successful PCI and a six-month CR programme, FMD values were equally improved in both stable angina and ACS patients.ope

Prognostic value of preoperative left ventricular global longitudinal strain for predicting postoperative myocardial injury and mortality in patients undergoing major non-cardiac surgery (SOLOMON study)

Background: The usefulness of preoperative measurement of left ventricular global longitudinal strain (LVGLS) for predicting prognosis in patients undergoing non-cardiac surgery has not been evaluated. We analyzed the prognostic value of LVGLS in predicting postoperative 30-day cardiovascular events and myocardial injury after non-cardiac surgery (MINS). Methods: This prospective cohort study was conducted in two referral hospitals and included 871 patients who underwent non-cardiac surgery <1 month after preoperative echocardiography. Those with ejection fraction <40%, valvular heart disease, and regional wall motion abnormality were excluded. The co-primary endpoints were the (1) composite incidence of all-cause death, acute coronary syndrome (ACS), and MINS and (2) com-posite incidence of all-cause death and ACS. Results: Among the 871 participants enrolled (mean age: 72.9 years; female: 60.8%), there were 43 cases of the primary endpoint (4.9%): 10 deaths, 3 ACS, and 37 MINS. Participants with impaired LVGLS (<= 16.6%) had a higher incidence of the co-primary endpoints (log-rank P < 0.001 and 0.015) than those without. The result was similar after adjustment with clinical variables and preoperative troponin T levels (hazard ratio = 1.30, 95% confidence interval [CI] = 1.03-1.65; P = 0.027). In sequential Cox analysis and net reclassification index, LVGLS had an incremental value for predicting the co-primary endpoints after non-cardiac surgery. Among the 538 (61.8%) participants who underwent serial troponin assay, LVGLS predicted MINS independently from the traditional risk factors (odds ratio = 3.54, 95% CI = 1.70-7.36; P = 0.001). Conclusions: Preoperative LVGLS has an independent and incremental prognostic value in predicting early postoperative cardiovascular events and MINS. Clinical Trial Registration: URL: https://trialsearch.who.int/. Unique identifiers: KCT0005147.ope

Artificial Intelligence-Enabled ECG Algorithm for the Prediction of Coronary Artery Calcification

Coronary artery calcium (CAC), which can be measured in various types of computed tomography (CT) examinations, is a hallmark of coronary artery atherosclerosis. However, despite the clinical value of CAC scores in predicting cardiovascular events, routine measurement of CAC scores is limited due to high cost, radiation exposure, and lack of widespread availability. It would be of great clinical significance if CAC could be predicted by electrocardiograms (ECGs), which are cost-effective and routinely performed during various medical checkups. We aimed to develop binary classification artificial intelligence (AI) models that predict CAC using only ECGs as input. Moreover, we aimed to address the generalizability of our model in different environments by externally validating our model on a dataset from a different institution. Among adult patients, standard 12-lead ECGs were extracted if measured within 60 days before or after the CAC scores, and labeled with the corresponding CAC scores. We constructed deep convolutional neural network models based on residual networks using only the raw waveforms of the ECGs as input, predicting CAC at different levels, namely CAC score ≥100, ≥400 and ≥1,000. Our AI models performed well in predicting CAC in the training and internal validation dataset [area under the receiver operating characteristics curve (AUROC) 0.753 ± 0.009, 0.802 ± 0.027, and 0.835 ± 0.024 for the CAC score ≥100, ≥400, and ≥1,000 model, respectively]. Our models also performed well in the external validation dataset (AUROC 0.718, 0.777 and 0.803 for the CAC score ≥100, ≥400, and ≥1,000 model, respectively), indicating that our model can generalize well to different but plausibly related populations. Model performance in terms of AUROC increased in the order of CAC score ≥100, ≥400, and ≥1,000 model, indicating that higher CAC scores might be associated with more prominent structural changes of the heart detected by the model. With our AI models, a substantial proportion of previously unrecognized CAC can be afforded with a risk stratification of CAC, enabling initiation of prophylactic therapy, and reducing the adverse consequences related to ischemic heart disease.ope

Cardiac Manifestations of Coronavirus Disease 2019 (COVID-19): a Multicenter Cohort Study

Background: This study aimed to investigate the cardiac manifestations of coronavirus disease 2019 (COVID-19). Methods: From February to March 2020, we prospectively and retrospectively enrolled consecutive patients diagnosed with COVID-19. Patient's data such as the demographic characteristics, symptoms, vital signs, laboratory and radiologic findings, electrocardiographic, and echocardiographic data, including the global longitudinal strain (GLS) of both ventricles, were obtained. Results: Forty patients (median age, 58 years; 50% men) were enrolled in the initial analysis. Patients were classified into severe and nonsevere groups based on the current guidelines. The 13 patients in the severe group were significantly older, had a greater prevalence of bilateral pneumonia and leukocytosis, and higher aspartate transaminase levels than patients in the nonsevere group. Patients in the severe group had a slightly lower left ventricular ejection fraction (LVEF) than those in the nonsevere group (median [interquartile range], 61.0% [58.5%, 62.3%] vs. 66.7% [60.6%, 69.8%], P = 0.015). In a subgroup of 34 patients in whom GLS could be analyzed, patients in the severe group had a significantly impaired left ventricular GLS (LVGLS) than those in the nonsevere group (-18.1% [-18.8%, -17.1%] vs. -21.7% [-22.9%, -19.9%], P = 0.001). There were no significant differences in total wall (RVGLStotal, -19.3% [-23.9%, -18.4%] vs. -24.3% [-26.0%, -22.6%], P = 0.060) and free wall (RVGLSfw, -22.7% [-27.2%, -18.6%] vs. -28.8% [-30.4%, -24.1%], P = 0.066) right ventricle GLS (RVGLS). Conclusion: Patients with severe COVID-19 had lower LVEF and LVGLS. RVGLS was not different between patients with severe and nonsevere COVID-19.ope

Red cell distribution width as a prognosticator in patients with heart failure

Aims: Increased red cell distribution width (RDW) is a poor prognostic factor in patients with heart failure (HF). However, only a few large-scale studies have identified the clinical utility of RDW after adjusting for covariates affecting RDW. Methods and results: From January 2010 to April 2021, we retrospectively enrolled patients diagnosed with HF from three referral hospitals with available RDW data (taken within 3 months of HF diagnosis) using an integrated clinical data system. Patients with an ejection fraction (EF) < 50% or HFA-PEFF (Heart Failure Association Pre-test assessment, Echocardiography and natriuretic peptide, Functional testing, Final aetiology) score ≥ 2 without severe valvular heart disease or coronary revascularization were enrolled. The primary endpoint was all-cause mortality, and cardiovascular mortality was also collected. Multivariable Cox regression analysis and stabilized inverse probability of treatment weighting (IPTW) were used to identify any association between RDW and all-cause death by balancing covariates or compounding factors. The global χ2 score was calculated and discrimination analysis was performed to evaluate the incremental value of RDW in predicting prognosis. Among the 6599 participants enrolled in this study, 1256 (19.0%) cases of all-cause death occurred, and the median duration of follow-up was 887 (interquartile range 351-1589) days. Elevated RDW at the initial diagnosis was associated with poor prognosis [cumulative incidence: 819 (30.2%) vs. 437 (11.2%), relative risk 1.58, 95% confidence interval (CI) 1.51-1.67, log-rank P < 0.001]. Multivariable Cox analysis showed that elevated RDW was a poor prognostic factor for the primary endpoint [hazard ratio (HR) 1.11, 95% CI 1.06-1.16, P < 0.001], independent of clinical risk factors, N-terminal pro-brain natriuretic peptide (NT-proBNP), and EF, which was concordant with the stabilized IPTW (HR 1.29, 95% CI 1.10-1.49, P < 0.001). Adding RDW to model composed of traditional risk factors, NT-proBNP, and echocardiographic parameters showed incremental prognostic value for predicting poor prognosis (area under the receiver operating characteristic curve, 0.799-0.826; P < 0.001). Conclusions: Increased RDW at the time of diagnosis is associated with poor prognosis in patients with HF, independent of clinical risk factors, such as NT-proBNP, and echocardiographic parameters. Therefore, RDW may aid in the management of these patients beyond traditional risk factors.ope

Comparative study of secondary hyperparthyroidism according to the mode of dialysis in patients with end-stage rena

의학과/석사[한글] 목적: 부갑상선호르몬은 말기신부전증 환자에서 요독물질로 작용하여 근골격계, 신경계, 심혈관계 및 혈구세포와 면역체계의 이상을 초래함으로써 환자의 이환율과 사망률에 영향을 주는 것으로 알려져 있다. 최근 부갑상선호르몬 농도의 다양한 임상적 의미가 여러 연구들을 통하여 밝혀지고 있으며 특히 생존의 예측인자로서의 가능성을 제시하는 연구도 있었다. 이에 본 연구는 투석 방법에 따른 이차성 부갑상선기능항진증의 유병률을 비교하고, 각 투석 치료군에 있어서 혈중 부갑상선호르몬 농도의 상승에 기여하는 인자들에 대하여 알아보고자 하였다. 대상 및 방법: 1996년 1월부터 2001년 6월까지 연세대학교 의과대학 부속 세브란스병원에서 말기신부전증으로 진단받고 최소한 6개월 이상 안정적으로 투석치료를 받고 있는 환자 328명의 의무기록을 검토하여 후향적인 연구로 진행하였으며, 부갑상선기능항진증은 부갑상선호르몬 농도가 정상의 3배 이상으로 증가하였을 때로 정의하였다. 결과 : 말기신부전증의 원인질환으로는 당뇨병이 101명(30.8%)으로 가장 많았고, 연구에 포함된 환자 중 170명(49.8%)에서 이차성 부갑상선기능항진증이 발생하였으며, 이 가운데 혈액투석 환자는 76명(53.9%), 복막투석 환자는 94명(50.2%)이었다. 부갑상선호르몬 농도의 평균값은 각 투석군 모두 투석 기간이 늘어남에 따라 증가하는 양상을 보였으며, 특히 투석 개시 후 40개월 이후부터는 혈액투석군이 복막투석군에 비하여 의미있게 높았다. 부갑상선기능항진증이 발생한 경우 양 투석군에서 alkaline phosphatase가 통계적으로 유의하게 증가되었고, 반면에 투석 시작전 기초검사로 시행한 크레아티닌 청소율은 양군 모두에서 의미있게 감소되었다. 부갑상선호르몬의 농도에 영향을 주는 인자로는 연령과 크레아티닌 청소율이 유의한 음의 상관관계를, 혈청 alkaline phosphatase와 인의 농도가 유의한 양의 상관관계를 보였다. 또한 복막투석군과 혈액투석군 모두에서 원인질환이 당뇨병인 경우 다른 원인질환을 가진 환자군에 비하여 부갑상선기능항진증의 발생빈도가 유의하게 낮았다. 같은 투석 기간에 있어서 이차성 부갑상선기능항진증의 발생률은 혈액투석 환자군이 복막투석 환자군에 비해 의미있게 높았다(RR=1.976, 95% CI:1.443-2.170 ; p<0.001). 결론: 혈액투석군과 복막투석군 모두 연령, 혈중 인 그리고 투석 치료를 시작할 당시 잔여 신기능의 정도가 부갑상선호르몬의 농도와 상관관계를 가지는 것으로 나타났다. 또한 투석기간이 늘어남에 따라 양 투석군 모두에서 부갑상선호르몬 농도와 이차성 부갑상선기능항진증의 발생률이 증가하였으며, 이는 복막투석 환자보다 혈액투석 환자에서 통계적으로 유의하게 높았다. 따라서, 조기 투석시작과 더불어 적극적인 고인산혈증에 대한 치료를 하는 것이 말기신부전증 환자에서 이차성 부갑상선기능항진증의 발생을 예방하는데 중요할 것으로 생각되며, 특히, 장기 혈액투석 환자의 경우 혈중 칼슘 및 인의 농도와 부갑상선호르몬 농도에 대한 보다 주의 깊은 관찰과 치료가 필요할 것으로 생각된다. [영문]Objectives : It has been well known that parathyroid hormone(PTH) plays an important role as a uremic toxin in patients with end-stage renal disease, and develops many abnormalities in musculo-skeletal, nervous, cardiovascular and immune systems, which contributes mortalities and morbidities of the patients. Recently, a number of researches have reported various clinical significances of PTH. The purposes of this study were to assess the prevalence of secondary hyperparathyroidism according to the modality and duration of dialysis in patients with ESRD and to determine the factors that attribute to increasing iPTH levels. Methods: From January 1996 to June 2001, 328 dialysis patients who have received maintenance hemodialysis or peritoneal dialysis more than 6 months at Severance Hospital, Seoul, Korea were included in this study. We studied retrospectively by reviewing their medical records and defined hyperparathyroidism, if iPTH level was increased more than three times of upper normal limit(≥195 pg/ml). Results: The number of patients with iPTH level greater than 195 pg/ml was 170(49.8%): HD 76(53.9%), CAPD 94(50.2%). The average level of iPTH was increased with dialysis duration in both groups, and also, significantly more increased in hemodialysis group than CAPD more than 40months after the beginning of dialysis (HD vs. CAPD; 41 to 60 months 363.6 ± 376.6 pg/ml vs. 215.8 ± 163.7 pg/ml, p<0.05; more than 61months 421.9 ± 380 pg/ml vs. 246.4 ± 196.3 pg/ml, p<0.05). The iPTH level was negatively correlated with age and creatinine clearance by simple and multiple regression analysis in both dialysis groups. Alkaline phosphatase and serum phosphorus levels had positive correlation with the level of iPTH in both CAPD and HD patients. Cox regression analysis showed an increment of development of secondary hyperparathyroidism with duration of dialysis. In patients on HD, the prevalence of secondary hyperparathyroidism was much higher than those on CAPD with statistical significance in patients on dialysis more than 40 months. Conclusion : In this study, iPTH level was correlated with age, serum phosphorus level and residual renal function at the initiation of dialysis in both groups. And also, in patients on HD, the average level of iPTH and the prevalence of secondary hyperparathyroidism were much higher than those on CAPD with statistical significance. So, we suggest that early dialysis and intensive attention to serum phosphorus level would be required in patients with ESRD for preventing the secondary hyperparathyroidism and more careful monitoring for serum calcium, phosphorus and parathyroid hormone with adequate treatments would be needed especially in hemodialysis patients.ope

Trickle Flow behavior of Metal Flow in Packed Coke Bed

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Grain refinement of α-iron by repeated carburization and decarburization reactions

MasterThe refinement technique using repeated carburizing and decarburizing and the pinning effect of sulfur and Fe3C against grain growth are researched. α → γ phase transformation refines the grain size, on the other hand, the opposite transformation does not. Repeated α - γ phase transformation makes grain size get smaller. Without pinning elements, grain refinement has limitation. Sulfur and Fe3C have grain boundary pinning effect. Sulfur does not have enough pinning effect on grains with the size of less than 30㎛. Fe3C supplies a lot of nucleation site for ferrite nuclei and retards ferrite grain growth up to 10㎛. Manganese stabilizes Fe3C at 800℃ so that Fe3C can help grain refinement by repeated phase transformation at 800℃