BACKGROUND Minimally invasive esophagectomy(MIE)is a widely accepted treatment for esophageal cancer,yet it is associated with a significant risk of surgical adverse events(SAEs),which can compromise patient recovery ...BACKGROUND Minimally invasive esophagectomy(MIE)is a widely accepted treatment for esophageal cancer,yet it is associated with a significant risk of surgical adverse events(SAEs),which can compromise patient recovery and long-term survival.Accurate preoperative identification of high-risk patients is critical for improving outcomes.AIM To establish and validate a risk prediction and stratification model for the risk of SAEs in patients with MIE.METHODS This retrospective study included 747 patients who underwent MIE at two centers from January 2019 to February 2024.Patients were separated into a train set(n=549)and a validation set(n=198).After screening by least absolute shrinkage and selection operator regression,multivariate logistic regression analyzed clinical and intraoperative variables to identify independent risk factors for SAEs.A risk stratification model was constructed and validated to predict the probability of SAEs.RESULTS SAEs occurred in 10.2%of patients in train set and 13.6%in the validation set.Patients with SAE had significantly higher complication rate and a longer hospital stay after surgery.The key independent risk factors identified included chronic obstructive pulmonary disease,a history of alcohol consumption,low forced expiratory volume in the first second,and low albumin levels.The stratification model has excellent prediction accuracy,with an area under the curve of 0.889 for the training set and an area under the curve of 0.793 for the validation set.CONCLUSION The developed risk stratification model effectively predicts the risk of SAEs in patients undergoing MIE,facilitating targeted preoperative interventions and improving perioperative management.展开更多
A numerical simulation was performed to study the flow pattern,mixing time and open-eye slag produced by argon gas injection in an industrial scale steel ladle under non-isothermal conditions.The liquid steel remains ...A numerical simulation was performed to study the flow pattern,mixing time and open-eye slag produced by argon gas injection in an industrial scale steel ladle under non-isothermal conditions.The liquid steel remains 5min before the injection,and thermal stratification and convective flows were analyzed.Three different sequences in stages employing various argon-gas flow rates were simulated.In the first case,a sequence with the highest flow rates of argon was applied,while in the second and the third sequences,the intermediate and the lowest flow rates of argon gas were used,respectively.For determining the chemistry homogenization,the mixing time was computed and analyzed in all three cases.It was found that the cold steel is located near the walls while the steel with a high temperature is accumulated in the center of the ladle above the argon-gas tuyere.The higher and lower flows promote a faster chemistry homogenization owing to the secondary recirculations that are developed closer to the walls.The results from steel temperature drop show a good concordance with plant trial measurements.展开更多
Stratified sampling is often used in opinion polls to reduce standard errors,and it is known as variance reduction technique in sampling theory.The most common approach of resampling method is based on bootstrapping t...Stratified sampling is often used in opinion polls to reduce standard errors,and it is known as variance reduction technique in sampling theory.The most common approach of resampling method is based on bootstrapping the dataset with replacement.A main purpose of this work is to investigate extensions of the resampling methods in classification problems,specifically we use decision trees,from a family of stratification models to improve prediction accuracy by aggregating classifiers built on a perturbed dataset.We use bagging,as a method of estimating a good decision boundary according to a family of stratification models.The overall conclusion is that for decision trees,un-stratified bootstrapping with bagging can yield lower error rates than other sampling strategies for simulated datasets.Based on the results in these experiments,a possible explanation as to why un-stratified sampling is a best is because bagging is itself a method of stratification.展开更多
Background The hybrid procedure for coronary heart disease combines minimally invasive coronary artery bypass grafting （CABG） and percutaneous coronary intervention （PCI） and is an alternative to revascularization...Background The hybrid procedure for coronary heart disease combines minimally invasive coronary artery bypass grafting （CABG） and percutaneous coronary intervention （PCI） and is an alternative to revascularization treatment. We sought to assess the predictive value of four risk-stratification models for risk assessment of major adverse cardiac and cerebrovascular events （MACCE） in patients with multivessel disease undergoing hybrid coronary revascularization. Methods The data of 120 patients were retrospectively collected and the SYNTAX score, EuroSCORE, SinoSCORE and the Global Risk Classification （GRC） calculated for each patient. The outcomes of interest were 2.7-year incidences of MACCE, including death, myocardial infarction, stroke, and any-vessel revascularization. Results During a mean of 2.7-year follow-up, actuarial survival was 99.17%, and no myocardial infarctions occurred. The discriminatory power （area under curve （AUC）） of the SYNTAX score, EuroSCORE, SinoSCORE and GRC for 2.7-year MACCE was 0.60 （95% confidence interval 0.42-0.77）, 0.65 （0.47-0.82）, 0.57 （0.39-0.75） and 0.65 （0.46-0.83）, respectively. The calibration characteristics of the SYNTAX score, EuroSCORE, SinoSCORE and GRC were 3.92 （P=0.86）, 5.39 （P=0.37）, 13.81 （P=0.32） and 0.02 （P=0.89）, respectively. Conclusions In patients with multivessel disease undergoing a hybrid procedure, the SYNTAX score, EuroSCORE, SinoSCORE and GRC were inaccurate in predicting MACCE. Modifying risk-stratification models to improve the predictive value for a hybrid procedure is needed.展开更多
Background Several risk stratification models have been developed for cardiac surgery. This study aimed to evaluate the accuracy of four existing risk stratification models, the Fuwai System for Cardiac Operative Risk...Background Several risk stratification models have been developed for cardiac surgery. This study aimed to evaluate the accuracy of four existing risk stratification models, the Fuwai System for Cardiac Operative Risk Evaluation （FuwaiSCORE）, the Society of Thoracic Surgeons 2008 cardiac surgery risk model for isolated valve surgery （the STS model）, the European System for Cardiac Operative Risk Evaluation （EuroSCORE） and the initial Parsonnet＇s score （the Parsonnet model） in predicting prolonged intensive care unit （ICU） stay in Chinese patients undergoing heart valve surgery. Methods Data were collected retrospectively from records of 1333 consecutive patients who received heart valve surgery in a single center between November 2006 and December 2007. Prolonged ICU stay was defined as not less than 124 hours. Calibration was assessed using the Hosmer-Lemeshow （H-L） goodness of fit test. Discrimination was assessed using the receiver-operating-characteristic （ROC） curve area. Results The FuwaiSCORE showed good calibration and discrimination compared with other risk models. According to the H-L statistics, the value of the FuwaiSCORE was 12.82, P 〉0.1. The area under ROC curve of the FuwaiSCORE was 0.81 （95%C/0.78-0.84）. Conclusions Our study suggests that the FuwaiSCORE is superior to the other three risk models in predicting prolonged length of ICU stay in Chinese patients with heart valve surgery. Having fewer variables, the system is much easier for bedside use than other systems.展开更多
Background:The impact of donor-recipient sex-matching patterns on the outcomes of liver transplantation(LT)remains controversial.We aim to compare the long-term graft and recipient survival of LT among four donor-reci...Background:The impact of donor-recipient sex-matching patterns on the outcomes of liver transplantation(LT)remains controversial.We aim to compare the long-term graft and recipient survival of LT among four donor-recipient sex-matching patterns using United Network of Organ Sharing(UNOS)database,and develop a grading system for prognostic stratification.Methods:Adult primary LT recipients from February,2002 to June,2022 in the UNOS database were divided into four donor-recipient sex groups,including female donor-female recipient(F-F)group,female donor-male recipient(F-M)group,male donor-female recipient(M-F)group and male donor-male recipient(M-M)group.Propensity score matching(PSM)analysis,inverse probability treatment weighting and multivariable adjustment were used to minimize between-group imbalances.Univariate and multivariate Cox regression analyses were performed to determine risk factors.Results:A total of 107,183 recipients were included,consisting of 46,037(43.0%)recipients in M-M group,25,699(24.0%)in F-M group,18,340(17.1%)in M-F group and 17,107(15.9%)in F-F group.After PSM,there were significant differences in the graft survival(GS)and overall survival(OS)among four groups(both P<0.001).F-F group showed best prognosis,with 1-,5-and 10-year GS of 89.1%,76.3%and 63.1%,respectively,while F-M group showed poor prognosis,with 1-,5-and 10-year GS of 87.4%,73.6%and 58.4%,respectively.In F-M group,three subgroups with distinctive prognosis were precisely stratified based on a grading system incorporating six independent risk factors.Conclusions:Donor-recipient sex-matching patterns significantly influence long-term LT outcomes.The grading system provides potential value to amend allocation process and optimize organ utility.展开更多
基金Supported by Joint Funds for the Innovation of Science and Technology,Fujian Province,No.2023Y9187 and No.2021Y9057.
文摘BACKGROUND Minimally invasive esophagectomy(MIE)is a widely accepted treatment for esophageal cancer,yet it is associated with a significant risk of surgical adverse events(SAEs),which can compromise patient recovery and long-term survival.Accurate preoperative identification of high-risk patients is critical for improving outcomes.AIM To establish and validate a risk prediction and stratification model for the risk of SAEs in patients with MIE.METHODS This retrospective study included 747 patients who underwent MIE at two centers from January 2019 to February 2024.Patients were separated into a train set(n=549)and a validation set(n=198).After screening by least absolute shrinkage and selection operator regression,multivariate logistic regression analyzed clinical and intraoperative variables to identify independent risk factors for SAEs.A risk stratification model was constructed and validated to predict the probability of SAEs.RESULTS SAEs occurred in 10.2%of patients in train set and 13.6%in the validation set.Patients with SAE had significantly higher complication rate and a longer hospital stay after surgery.The key independent risk factors identified included chronic obstructive pulmonary disease,a history of alcohol consumption,low forced expiratory volume in the first second,and low albumin levels.The stratification model has excellent prediction accuracy,with an area under the curve of 0.889 for the training set and an area under the curve of 0.793 for the validation set.CONCLUSION The developed risk stratification model effectively predicts the risk of SAEs in patients undergoing MIE,facilitating targeted preoperative interventions and improving perioperative management.
文摘A numerical simulation was performed to study the flow pattern,mixing time and open-eye slag produced by argon gas injection in an industrial scale steel ladle under non-isothermal conditions.The liquid steel remains 5min before the injection,and thermal stratification and convective flows were analyzed.Three different sequences in stages employing various argon-gas flow rates were simulated.In the first case,a sequence with the highest flow rates of argon was applied,while in the second and the third sequences,the intermediate and the lowest flow rates of argon gas were used,respectively.For determining the chemistry homogenization,the mixing time was computed and analyzed in all three cases.It was found that the cold steel is located near the walls while the steel with a high temperature is accumulated in the center of the ladle above the argon-gas tuyere.The higher and lower flows promote a faster chemistry homogenization owing to the secondary recirculations that are developed closer to the walls.The results from steel temperature drop show a good concordance with plant trial measurements.
基金we would like to acknowledge the Research and Consulting Centre(RCC),University of Benghazi,Libya for funded this work.
文摘Stratified sampling is often used in opinion polls to reduce standard errors,and it is known as variance reduction technique in sampling theory.The most common approach of resampling method is based on bootstrapping the dataset with replacement.A main purpose of this work is to investigate extensions of the resampling methods in classification problems,specifically we use decision trees,from a family of stratification models to improve prediction accuracy by aggregating classifiers built on a perturbed dataset.We use bagging,as a method of estimating a good decision boundary according to a family of stratification models.The overall conclusion is that for decision trees,un-stratified bootstrapping with bagging can yield lower error rates than other sampling strategies for simulated datasets.Based on the results in these experiments,a possible explanation as to why un-stratified sampling is a best is because bagging is itself a method of stratification.
文摘Background The hybrid procedure for coronary heart disease combines minimally invasive coronary artery bypass grafting （CABG） and percutaneous coronary intervention （PCI） and is an alternative to revascularization treatment. We sought to assess the predictive value of four risk-stratification models for risk assessment of major adverse cardiac and cerebrovascular events （MACCE） in patients with multivessel disease undergoing hybrid coronary revascularization. Methods The data of 120 patients were retrospectively collected and the SYNTAX score, EuroSCORE, SinoSCORE and the Global Risk Classification （GRC） calculated for each patient. The outcomes of interest were 2.7-year incidences of MACCE, including death, myocardial infarction, stroke, and any-vessel revascularization. Results During a mean of 2.7-year follow-up, actuarial survival was 99.17%, and no myocardial infarctions occurred. The discriminatory power （area under curve （AUC）） of the SYNTAX score, EuroSCORE, SinoSCORE and GRC for 2.7-year MACCE was 0.60 （95% confidence interval 0.42-0.77）, 0.65 （0.47-0.82）, 0.57 （0.39-0.75） and 0.65 （0.46-0.83）, respectively. The calibration characteristics of the SYNTAX score, EuroSCORE, SinoSCORE and GRC were 3.92 （P=0.86）, 5.39 （P=0.37）, 13.81 （P=0.32） and 0.02 （P=0.89）, respectively. Conclusions In patients with multivessel disease undergoing a hybrid procedure, the SYNTAX score, EuroSCORE, SinoSCORE and GRC were inaccurate in predicting MACCE. Modifying risk-stratification models to improve the predictive value for a hybrid procedure is needed.
基金This research was supported by a grant from the National Natural Science Foundation of China （No. 30772149）.Acknowledgements： We are grateful to CHEN Tao （Fuwai Hospital） for his statistical advice.
文摘Background Several risk stratification models have been developed for cardiac surgery. This study aimed to evaluate the accuracy of four existing risk stratification models, the Fuwai System for Cardiac Operative Risk Evaluation （FuwaiSCORE）, the Society of Thoracic Surgeons 2008 cardiac surgery risk model for isolated valve surgery （the STS model）, the European System for Cardiac Operative Risk Evaluation （EuroSCORE） and the initial Parsonnet＇s score （the Parsonnet model） in predicting prolonged intensive care unit （ICU） stay in Chinese patients undergoing heart valve surgery. Methods Data were collected retrospectively from records of 1333 consecutive patients who received heart valve surgery in a single center between November 2006 and December 2007. Prolonged ICU stay was defined as not less than 124 hours. Calibration was assessed using the Hosmer-Lemeshow （H-L） goodness of fit test. Discrimination was assessed using the receiver-operating-characteristic （ROC） curve area. Results The FuwaiSCORE showed good calibration and discrimination compared with other risk models. According to the H-L statistics, the value of the FuwaiSCORE was 12.82, P 〉0.1. The area under ROC curve of the FuwaiSCORE was 0.81 （95%C/0.78-0.84）. Conclusions Our study suggests that the FuwaiSCORE is superior to the other three risk models in predicting prolonged length of ICU stay in Chinese patients with heart valve surgery. Having fewer variables, the system is much easier for bedside use than other systems.
基金supported by The National Key Research and Development Program of China(No.2021YFA1100500)Key Research&Development Program of Zhejiang Province(No.2022C03108)+1 种基金Leading Innovation Team of Hangzhou Medical College:Clinical Research in Organ Transplantation(No.CXLJ202401)The Major Research Plan of the National Natural Science Foundation(No.92159202).
文摘Background:The impact of donor-recipient sex-matching patterns on the outcomes of liver transplantation(LT)remains controversial.We aim to compare the long-term graft and recipient survival of LT among four donor-recipient sex-matching patterns using United Network of Organ Sharing(UNOS)database,and develop a grading system for prognostic stratification.Methods:Adult primary LT recipients from February,2002 to June,2022 in the UNOS database were divided into four donor-recipient sex groups,including female donor-female recipient(F-F)group,female donor-male recipient(F-M)group,male donor-female recipient(M-F)group and male donor-male recipient(M-M)group.Propensity score matching(PSM)analysis,inverse probability treatment weighting and multivariable adjustment were used to minimize between-group imbalances.Univariate and multivariate Cox regression analyses were performed to determine risk factors.Results:A total of 107,183 recipients were included,consisting of 46,037(43.0%)recipients in M-M group,25,699(24.0%)in F-M group,18,340(17.1%)in M-F group and 17,107(15.9%)in F-F group.After PSM,there were significant differences in the graft survival(GS)and overall survival(OS)among four groups(both P<0.001).F-F group showed best prognosis,with 1-,5-and 10-year GS of 89.1%,76.3%and 63.1%,respectively,while F-M group showed poor prognosis,with 1-,5-and 10-year GS of 87.4%,73.6%and 58.4%,respectively.In F-M group,three subgroups with distinctive prognosis were precisely stratified based on a grading system incorporating six independent risk factors.Conclusions:Donor-recipient sex-matching patterns significantly influence long-term LT outcomes.The grading system provides potential value to amend allocation process and optimize organ utility.
