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Harmful algal blooms (HABs) are a serious threat to ecosystems and human health. The accurate prediction of HABs is crucial for their proactive preparation and management. While mechanism-based numerical modeling, such as the Environmental Fluid Dynamics Code (EFDC), has been widely used in the past, the recent development of machine learning technology with data-based processing capabilities has opened up new possibilities for HABs prediction. In this study, we developed and evaluated two types of machine learning-based models for HABs prediction: Gradient Boosting models (XGBoost, LightGBM, CatBoost) and attention-based CNN-LSTM models. We used Bayesian optimization techniques for hyperparameter tuning, and applied bagging and stacking ensemble techniques to obtain the final prediction results. The final prediction result was derived by applying the optimal hyperparameter and bagging and stacking ensemble techniques, and the applicability of prediction to HABs was evaluated. When predicting HABs with an ensemble technique, it is judged that the overall prediction performance can be improved by complementing the advantages of each model and averaging errors such as overfitting of individual models. Our study highlights the potential of machine learning-based models for HABs prediction and emphasizes the need to incorporate the latest technology into this important field.

Harmful algal blooms (HABs) caused by harmful cyanobacteria adversely impact the water quality in aquatic ecosystems and burden socioecological systems that are based on water utilization. Currently, Korea uses the Environmental Fluid Dynamics Code-National Institute of Environmental Research (EFDC-NIER) model to predict algae conditions and respond to algal blooms through the HAB alert system. This study aimed to establish an additional deep learning model to effectively respond to algal blooms. The prediction model is based on a deep neural network (DNN), which is a type of artificial neural network widely used for HAB prediction. By applying the synthetic minority over-sampling technique (SMOTE) to resolve the imbalance in the data, the DNN model showed improved performance during validation for predicting the number of cyanobacteria cells. The R-squared increased from 0.7 to 0.78, MAE decreased from 0.7 to 0.6, and RMSE decreased from 0.9 to 0.7, indicating an enhancement in the model’s performance. Furthermore, regarding the HAB alert levels, the R-squared increased from 0.18 to 0.79, MAE decreased from 0.2 to 0.1, and RMSE decreased from 0.3 to 0.2, indicating improved performance as well. According to the results, the constructed data-based model reasonably predicted algae conditions in the summer when algal bloom-induced damage occurs and accurately predicted the HAB alert levels for immediate decision-making. The main objective of this study was to develop a new technology for predicting and managing HABs in river environments, aiming for a sustainable future for the aquatic ecosystem.

Cardiac rehabilitation (CR) can reduce cardiovascular mortality and morbidity in coronary artery disease. Long coronary artery lesions may be associated with adverse outcomes afterdrug-eluting stent (DES) implantation. The purpose of this study was to evaluate angiographic outcomes after a comprehensive CR program in patients with DESs for long coronary artery lesions. A total of 576 patients treated with DESs for long (≥25 mm) coronary lesions were enrolled in this prospective CR registry. Comprehensive CR programs were successfully performed in 288 patients (50%). The primary end point was in-stent late luminal loss at the 9-month angiographic follow-up. There were few significant differences between the CR and non-CR groups in terms of baseline characteristics, including clinical, angiographic, and procedural variables. The rate of in-stent late luminal loss in the CR group was 35% less than in the usual care group (0.19 ± 0.33 mm in CR vs 0.29 ± 0.45 mm in non-CR, difference 0.08 mm, 95% confidence interval 0.01 to 0.16, p = 0.02) at the 9-month follow-up. After propensity-matched analysis (224 pairs), the results were consistent (0.18 ± 0.31 mm in CR vs 0.28 ± 0.41 mm in non-CR, difference 0.10 mm, 95% confidence interval 0.02 to 0.18, p = 0.02). The CR group showed a significant improvement in the overall risk profile compared with the non-CR group, including current smoking, biochemical profiles, depression, obesity, and exercise capacity. In conclusion, the comprehensive CR program significantly reduced late luminal loss after DES implantation for long coronary lesions. This may be associated with significant improvements in exercise capacity and overall risk profile. [ABSTRACT FROM AUTHOR]

Many studies have reported comparable risk of hard end points between percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) for unprotected left main coronary artery (ULMCA) stenosis. However, there are limited data regarding the morbidity associated with ULMCA revascularization. This study sought to compare the cause and risk of readmissions after PCI and CABG for ULMCA stenosis. We evaluated the unadjusted and adjusted risk of readmissions in 1,352 patients (783 PCI treated and 569 CABG treated) who were consecutively enrolled in a multicenter registry of patients with ULMCA stenosis, named the Premier of Randomized Comparison of Bypass Surgery versus Angioplasty Using Sirolimus-Eluting Stent in Patients with Left Main Coronary Artery Disease trial. Overall, 206 PCI-treated patients (26.3%) experienced at least 1 readmission after the index procedure during 48.7 - 16.0 months of follow-up compared with 84 CABG-treated patients (14.8%, p <0.001). The most frequent causes of readmission were repeat revascularization after PCI (41%) and noncardiac readmissions after CABG (48%). Through repeated events analysis, PCI was associated with more frequent readmissions than CABG (hazard ratio 2.037, 95% confidence interval 1.542 to 2.692, p <0.001), being an independent predictor of readmission (hazard ratio 1.820, 95% confidence interval 1.420 to 2.331, p <0.001). Except for the acute period, defined as the first 3 months, when there was no significant difference in readmission rate, a higher readmission rate after PCI was consistently observed over the remainder of the follow-up period. In conclusion, PCI was shown to be associated with a higher risk of readmission than CABG in treating ULMCA disease. This higher risk was attributable to more frequent revascularization in the PCI group. [ABSTRACT FROM AUTHOR]

There are no practical criteria for the use of triple antiplatelet therapy after drug-eluting stent (DES) implantation. In our present report, pooled analysis of 3 randomized studies in patients with diabetes mellitus (Drug-Eluting Stenting Followed by Cilostazol treatment reduces LAte Restenosis in patients with diabetes mellitus trial) and long coronary narrowings (Drug-Eluting Stenting Followed by Cilostazol Treatment Reduces Late Restenosis in Patients with Long Coronary Lesions trials I and II) compared triple (aspirin, clopidogrel, and cilostazol; triple group, n = 700) and dual antiplatelet therapies (aspirin and clopidogrel; dual group, n = 699) after DES implantation. Among pooled population (n = 1,399 patients), 1,173 patients with follow-up angiography were divided into 3 stent length categories (≤20, 20 to 40, and >40 mm). There was no statistical significance of in-stent restenosis (ISR) in ≤20- and 20- to 40-mm categories between 2 groups. However, ISR rate was significantly reduced in triple versus dual group in >40-mm stent length category (12.4% vs 22.1%, p = 0.008). In diabetic patients, triple group also showed significant reduction in the ISR rate in >40-mm stent length category (15.4% vs 32.3%, p = 0.003). According to postprocedural minimal lumen diameter, triple group showed a trend toward a lower ISR than that of the dual group in all categories (p = 0.033 for ≤2.5 mm, p = 0.087 for 2.5 to 3.0 mm, and p = 0.119 for >3.0 mm). In conclusion, the triple group had a significantly reduced ISR in patients with >40-mm stent length after DES implantation compared with the dual group. Therefore, this suggestion for use of triple antiplatelet therapy could be easily applied after DES implantation in routine clinical practice. [ABSTRACT FROM AUTHOR]

BACKGROUND: The optimal functional evaluation of coronary artery stenosis in patients with severe aortic stenosis (AS) has not been established. The objective of the study was to evaluate the instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR) in patients with and without severe AS. METHODS: We retrospectively investigated 395 lesions in 293 patients with severe AS and 2257 lesions in 1882 patients without severe AS between 2010 and 2022 from a subgroup of the Interventional Cardiology Research In-Cooperation Society FFR Registry. All patients had FFR values, and iFR was analyzed post hoc using dedicated software only in lesions with adequate resting pressure curves (311 lesions in patients with severe AS and 2257 lesions in patients with nonsevere AS). RESULTS: The incidence of iFR =0.89 was 66.6% and 31.8% (P<0.001), while the incidence of FFR =0.80 was 45.3% and 43.9% (P=0.60) in the severe AS group and the nonsevere AS group, respectively. In the severe AS group, most lesions (95.2%) with iFR >0.89 had FFR >0.80, while 36.2% of lesions with iFR =0.89 had FFR >0.80. During a median follow-up of 2 years, FFR =0.80 was significantly associated with deferred lesion failure (adjusted hazard ratio, 2.71 [95% CI, 1.08-6.80]; P=0.034), while iFR =0.89 showed no prognostic value (adjusted hazard ratio, 1.31 [95% CI, 0.47-3.60]; P=0.60) in the severe AS group. Lesions with iFR =0.89 and FFR >0.80, in particular, were not associated with a higher rate of deferred lesion failure at 3 years compared with lesions with iFR >0.89 (15.4% versus 17.0%; P=0.58). CONCLUSIONS: This study suggested that FFR appears to be less affected by the presence of severe AS and is more associated with prognosis. iFR may overestimate the functional severity of coronary artery disease without prognostic significance, yet it can be useful for excluding significant stenosis in patients with severe AS. [ABSTRACT FROM AUTHOR]

Green algae play an important role in ecosystems as primary producers, but they can cause algal blooms, which are socio-environmental burdens as responding to them requires water resources from dam reservoirs. This study proposes an alternative for reducing algal blooms through dam operation without using additional water resources. A novel oscillation flow concept was suggested: oscillating discharge of dam for irregular flow. To examine its effect, the Environmental Fluid Dynamics Code—National Institute of Environment Research (EFDC-NIER) model was constructed and calibrated for the Namhan River, South Korea, from downstream of the Chungju Dam to downstream of Gangcheon Weir. The water quality in the study area were simulated and analyzed for August 2019, which is when the largest number of harmful cyanobacteria had been reported in recent years. Our results showed that the oscillation flow produced significant variance of flow velocity, and algal bloom density in the Namhan River was reduced by 20–30% through the operation of the Chungju Dam. However, further study and investigation are required before practical application.

Cyanobacterial Harmful Algal Blooms (CyanoHABs) produce toxins and odors in public water bodies and drinking water. Current process-based models predict algal blooms by modeling chlorophyll-a concentrations. However, chlorophyll-a concentrations represent all algae and hence, a method for predicting the proportion of harmful cyanobacteria is required. We proposed a technique to predict harmful cyanobacteria concentrations based on the source codes of the Environmental Fluid Dynamics Code from the National Institute of Environmental Research. A graphical user interface was developed to generate information about general water quality and algae which was subsequently used in the model to predict harmful cyanobacteria concentrations. Predictive modeling was performed for the Hapcheon-Changnyeong Weir–Changnyeong-Haman Weir section of the Nakdong River, South Korea, from May to October 2019, the season in which CyanoHABs predominantly occur. To evaluate the success rate of the proposed model, a detailed five-step classification of harmful cyanobacteria levels was proposed. The modeling results demonstrated high prediction accuracy (62%) for harmful cyanobacteria. For the management of CyanoHABs, rather than chlorophyll-a, harmful cyanobacteria should be used as the index, to allow for a direct inference of their cell densities (cells/mL). The proposed method may help improve the existing Harmful Algae Alert System in South Korea.

Process-based modeling for predicting harmful cyanobacteria is affected by a variety of factors, including the initial conditions, boundary conditions (tributary inflows and atmosphere), and mechanisms related to cyanobacteria growth and death. While the initial conditions do not significantly affect long-term predictions, the initial cyanobacterial distribution in water is particularly important for short-term predictions. Point-based observation data have typically been used for cyanobacteria prediction of initial conditions. These initial conditions are determined through the linear interpolation of point-based observation data and may differ from the actual cyanobacteria distribution. This study presents an optimal method of applying hyperspectral images to establish the Environmental Fluid Dynamics Code-National Institute of Environment Research (EFDC-NIER) model initial conditions. Utilizing hyperspectral images to determine the EFDC-NIER model initial conditions involves four steps that are performed sequentially and automated in MATLAB. The EFDC-NIER model is established using three grid resolution cases for the Changnyeong-Haman weir section of the Nakdong River Basin, where Microcystis dominates during the summer (July to September). The effects of grid resolution on (1) water quality modeling and (2) initial conditions determined using cumulative distribution functions are evaluated. Additionally, the differences in Microcystis values are compared when applying initial conditions using hyperspectral images and point-based evaluation data. Hyperspectral images allow detailed initial conditions to be applied in the EFDC-NIER model based on the plane-unit cyanobacterial information observed in grids, which can reduce uncertainties in water quality (cyanobacteria) modeling.

Background: Numerous randomised trials have compared coronary artery bypass grafting (CABG) with percutaneous coronary intervention (PCI) for patients with coronary artery disease. However, no studies have been powered to detect a difference in mortality between the revascularisation strategies.Methods: We did a systematic review up to July 19, 2017, to identify randomised clinical trials comparing CABG with PCI using stents. Eligible studies included patients with multivessel or left main coronary artery disease who did not present with acute myocardial infarction, did PCI with stents (bare-metal or drug-eluting), and had more than 1 year of follow-up for all-cause mortality. In a collaborative, pooled analysis of individual patient data from the identified trials, we estimated all-cause mortality up to 5 years using Kaplan-Meier analyses and compared PCI with CABG using a random-effects Cox proportional-hazards model stratified by trial. Consistency of treatment effect was explored in subgroup analyses, with subgroups defined according to baseline clinical and anatomical characteristics.Findings: We included 11 randomised trials involving 11 518 patients selected by heart teams who were assigned to PCI (n=5753) or to CABG (n=5765). 976 patients died over a mean follow-up of 3·8 years (SD 1·4). Mean Synergy between PCI with Taxus and Cardiac Surgery (SYNTAX) score was 26·0 (SD 9·5), with 1798 (22·1%) of 8138 patients having a SYNTAX score of 33 or higher. 5 year all-cause mortality was 11·2% after PCI and 9·2% after CABG (hazard ratio [HR] 1·20, 95% CI 1·06-1·37; p=0·0038). 5 year all-cause mortality was significantly different between the interventions in patients with multivessel disease (11·5% after PCI vs 8·9% after CABG; HR 1·28, 95% CI 1·09-1·49; p=0·0019), including in those with diabetes (15·5% vs 10·0%; 1·48, 1·19-1·84; p=0·0004), but not in those without diabetes (8·7% vs 8·0%; 1·08, 0·86-1·36; p=0·49). SYNTAX score had a significant effect on the difference between the interventions in multivessel disease. 5 year all-cause mortality was similar between the interventions in patients with left main disease (10·7% after PCI vs 10·5% after CABG; 1·07, 0·87-1·33; p=0·52), regardless of diabetes status and SYNTAX score.Interpretation: CABG had a mortality benefit over PCI in patients with multivessel disease, particularly those with diabetes and higher coronary complexity. No benefit for CABG over PCI was seen in patients with left main disease. Longer follow-up is needed to better define mortality differences between the revascularisation strategies.Funding: None. [ABSTRACT FROM AUTHOR]

Periprocedural myocardial infarction (MI) can be induced by several angiographic mechanisms. However, there are limited data on whether these mechanisms differentially affect clinical outcomes. The purpose of our study was to investigate the impact of periprocedural MI on mortality according to the underlying angiographic mechanisms after drug-eluting stent (DES) implantation. We pooled the databases from 7 coronary stent trials using DES. Periprocedural MI was classified according to its underlying angiographic mechanisms as type 1 (due to side-branch occlusion), type 2 (due to other angiographic complications), or type 3 (without angiographically identifiable causes). Among 10,889 patients treated with DES, 768 (7.1%) experienced periprocedural MI; 463 cases (60.3%) were driven by type 1 cause, 138 (18.0%) by type 2 cause, and 167 (21.7%) by type 3 cause. Mortality rates at 2 years were higher in patients with periprocedural MI than in those without (3.5% vs 2.1%, respectively). Significant differences in mortality were observed according to the angiographic mechanisms of MI (type 1: 2.8% vs type 2: 6.1% vs type 3: 3.1%). After multivariable adjustment, type 2 MI was significantly associated with an increased risk of mortality (hazard ratio 2.65, 95% confidence interval 1.77 to 3.96), whereas type 1 and type 3 MI were not related with increased mortality. In conclusion, among patients receiving DES implantation, periprocedural MI was associated with increased mortality, and there were differential associations with mortality according to the underlying angiographic mechanisms. [ABSTRACT FROM AUTHOR]

There are limited data regarding the role of coronary computed tomographic angiography (CCTA) in asymptomatic patients with type 2 diabetes mellitus. We analyzed 557 asymptomatic type 2 diabetic patients who underwent CCTA. Cardiac event was defined as a composite of cardiac death, nonfatal myocardial infarction, acute coronary syndrome requiring hospitalization, or late revascularization. Atherosclerotic plaques were observed in 395 patients (70.9%), and 170 patients (30.5%) showed significant coronary artery disease (CAD) on CCTA. Ninety-two patients (16.5%) were associated with a significant stenosis in the left main or proximal left anterior descending artery. During the follow-up period (33.7 ± 7.8 months), although an excellent prognosis was observed in patients without significant CAD on CCTA, those with significant CAD showed more cardiac events (7.1% vs 0.5%) and lower 3-year event-free survival rates (99.2 ± 0.6% vs 90.9 ± 2.6%, p <0.001). Furthermore, in group with significant CAD, patients with significant CAD in the left main or proximal left anterior descending artery had more cardiac events (10.9% vs 2.6%) and lower 3-year event-free survival rates (97.4 ± 1.8% vs 86.1 ± 4.2%, p = 0.049). On multivariate analysis, family history of premature CAD, previous history of stroke, higher UK Prospective Diabetes Study 10-year risk scores, neuropathy, and retinopathy were independent clinical predictors of having significant CAD and left main or proximal left anterior descending artery significant CAD on CCTA. In conclusion, about 1/3 of asymptomatic type 2 diabetic patients had significant CAD on CCTA with a subsequent high risk for cardiac events. These findings suggest that CCTA may have a potential role in identifying patients with high cardiovascular risks in asymptomatic type 2 diabetes. [ABSTRACT FROM AUTHOR]

Angiographic and clinical outcomes remain relatively unfavorable for diabetic patients even after the use of drug-eluting stent. This prospective, multicenter, randomized study compared the relative efficacy and safety of resolute zotarolimus-eluting stent (R-ZES) and sirolimus-eluting stent (SES) implantation in diabetic patients with coronary artery disease. The primary end point was noninferiority of angiographic in-segment late loss at 9 months. Clinical events were also monitored for at least 12 months. Patient recruitment was prematurely stopped after enrollment of 256 patients (127 in R-ZES group and 129 in SES) because of discontinuing production of SES. The R-ZES was noninferior to the SES for 9- month in-segment late loss (0.34 - 0.30 vs 0.39 - 0.43 mm; difference L0.048; 95% confidence interval L0.157 to 0.061; upper 1-sided 95% confidence interval 0.044; p <0.001 for noninferiority). In addition, in-stent late loss (0.22 - 0.29 vs 0.21 - 0.40 mm, p [ 0.849) and the rates of in-segment (1.2% vs 6.7%, p [ 0.119) and in-stent (1.2% vs 3.3%, p [ 0.621) binary restenoses were similar between the 2 groups. At 12 months, there were no statistical differences between the 2 groups in the incidence of any clinical outcomes (death, myocardial infarction, stent thrombosis, ischemia-driven target lesion revascularization, ischemia-driven target vessel revascularization, and composite outcomes). In conclusion, despite having reduced power because of early study termination, our study suggests that the R-ZES has noninferior angiographic outcomes at 9 months to the SES in diabetic patients with coronary artery disease. [ABSTRACT FROM AUTHOR]

Background: Percutaneous coronary intervention (PCI) is increasingly used to treat unprotected left main coronary artery stenosis, although coronary-artery bypass grafting (CABG) has been considered to be the treatment of choice. Methods: We randomly assigned patients with unprotected left main coronary artery stenosis to undergo CABG (300 patients) or PCI with sirolimus-eluting stents (300 patients). Using a wide margin for noninferiority, we compared the groups with respect to the primary composite end point of major adverse cardiac or cerebrovascular events (death from any cause, myocardial infarction, stroke, or ischemia-driven target-vessel revascularization) at 1 year. Event rates at 2 years were also compared between the two groups. Results: The primary end point occurred in 26 patients assigned to PCI as compared with 20 patients assigned to CABG (cumulative event rate, 8.7% vs. 6.7%; absolute risk difference, 2.0 percentage points; 95% confidence interval [CI], −1.6 to 5.6; P=0.01 for noninferiority). By 2 years, the primary end point had occurred in 36 patients in the PCI group as compared with 24 in the CABG group (cumulative event rate, 12.2% vs. 8.1%; hazard ratio with PCI, 1.50; 95% CI, 0.90 to 2.52; P=0.12). The composite rate of death, myocardial infarction, or stroke at 2 years occurred in 13 and 14 patients in the two groups, respectively (cumulative event rate, 4.4% and 4.7%, respectively; hazard ratio, 0.92; 95% CI, 0.43 to 1.96; P=0.83). Ischemia-driven target-vessel revascularization occurred in 26 patients in the PCI group as compared with 12 patients in the CABG group (cumulative event rate, 9.0% vs. 4.2%; hazard ratio, 2.18; 95% CI, 1.10 to 4.32; P=0.02). Conclusions: In this randomized trial involving patients with unprotected left main coronary artery stenosis, PCI with sirolimus-eluting stents was shown to be noninferior to CABG with respect to major adverse cardiac or cerebrovascular events. However, the noninferiority margin was wide, and the results cannot be considered clinically directive. (Funded by the Cardiovascular Research Foundation, Seoul, Korea, and others; PRECOMBAT ClinicalTrials.gov number, NCT00422968.) N Engl J Med 2011;364:1718-27. [ABSTRACT FROM AUTHOR]