Risk stratification for in-hospital mortality after cardiac surgery: external validation of EuroSCORE II in a prospective regional registry

Validation of the European system for cardiac operative risk evaluation II in a large Taiwan cardiac surgical centre

BACKGROUND

The European System for Cardiac Operative Risk Evaluation (EuroSCORE II) is a well-established scoring system for predicting mortality in cardiac surgery. This system was derived predominantly from a European patient cohort; however, no validation of this system has been conducted in Taiwan. We sought to assess the performance of EuroSCORE II at a tertiary centre.

METHODS

The 2161 adult patients receiving cardiac surgery between 2017 and 2020 in our institution were included.

RESULTS

Overall, the in-hospital mortality rate was 7.89%. The performance of EuroSCORE II was assessed using the area under the receiver operator curve (AUC) for discrimination and the Hosmer-Lemeshow (H-L) test for calibration. Data were analysed for type of surgery, risk stratification, and status of the operation. EuroSCORE II had good discriminative power (AUC=0.854, 95% Confidence Interval (CI): 0.822-0.885) and good calibration (χ2=5.19, p=0.82) for all types of surgery except ventricular assist devices (AUC=0.618, 95% CI: 0.497-0.738). EuroSCORE II also showed good calibration for most types of surgery except coronary artery bypass surgery (CABG) combined procedure (P=0.033), heart transplantation (HT) (P=0.017), and urgent operation (P=0.041). EuroSCORE II significantly underestimated the risk for CABG combined procedure and urgent operations, and overestimated the risk for HT.

CONCLUSION

EuroSCORE II had satisfactory discrimination and calibration power to predict surgical mortality in Taiwan. However, the model is poorly calibrated for CABG combined procedure, HT, urgent operation, and, likely, lower- and higher-risk patients.

Combination of the triglyceride-glucose index and EuroSCORE II improves the prediction of long-term adverse outcomes in patients undergoing coronary artery bypass grafting

AIMS

We aimed to investigate the independent and combined association of the triglyceride-glucose (TyG) index and EuroSCORE II with major adverse cardiovascular event (MACE) after coronary artery bypass grafting (CABG), and examine whether the addition of the TyG index improves the predictive performance of the EuroSCORE II.

MATERIALS AND METHODS

This study included 1013 patients who underwent CABG. The primary endpoint was MACE, which was defined as the composite of all-cause death, repeat coronary artery revascularisation, non-fatal myocardial infarction and non-fatal stroke. The patients were grouped by the TyG index and EuroSCORE II tertiles and the combination of these risk indicators.

RESULTS

During the follow-up, 211 individuals developed MACE. Elevated levels of the TyG index and EuroSCORE II were associated with an increased risk of MACE. The hazard ratio [95% confidence interval (CI)] was 3.66 (2.34-5.73) in patients with the highest tertile of the TyG index and EuroSCORE II. Compared with the EuroSCORE II alone, combining the TyG index with EuroSCORE II achieved a better predictive performance [C-statistic increased 0.032, p < 0.001; continuous net reclassification improvement (NRI) (95% CI): 0.364 (0.215-0.514), p < 0.001; integrated discrimination improvement (IDI) (95% CI): 0.015 (0.007-0.023), p < 0.001, Akaike's information criteria (AIC) and Bayesian information criterion (BIC) decreased, and the likelihood ratio test, p < 0.001].

CONCLUSIONS

The TyG index and EuroSCORE II are independently associated with poor prognosis. Furthermore, the TyG index is an important adjunct to the EuroSCORE II for improving risk stratification and guiding early intervention among post-CABG patients.

Validation of EuroSCORE II in atrial fibrillation heart surgery patients from the KROK Registry

The study aimed to validate the European System for Cardiac Operative Risk Evaluation score (EuroSCORE II) in patients with atrial fibrillation (AF). All data were retrieved from the National Registry of Cardiac Surgery Procedures (KROK). EuroSCORE II calibration and discrimination performance was evaluated. The final cohort consisted of 44,172 patients (median age 67, 30.8% female, 13.4% with AF). The in-hospital mortality rate was 4.14% (N = 1830), and 5.21% (N = 2303) for 30-day mortality. EuroSCORE II significantly underestimated mortality in mild- and moderate-risk populations [Observed (O):Expected (E)-1.1, 1.16). In the AF subgroup, it performed well [O:E-0.99), whereas in the very high-risk population overestimated mortality (O:E-0.9). EuroSCORE II showed better discrimination in AF (-) [area under curve (AUC) 0.805, 95% CI 0.793-0.817)] than in AF (+) population (AUC 0.791, 95%CI 0.767-0.816), P < 0.001. The worst discriminative performance for the AF (+) group was for coronary artery bypass grafting (CABG) (AUC 0.746, 95% CI 0.676-0.817) as compared with AF (-) population (AUC 0.798, 95% CI 0.774-0.822), P < 0.001. EuroSCORE II is more accurate for patients with AF. However, it underestimated mortality rates for low-to-moderate-risk patients and had a lower ability to distinguish between high- and low-risk patients with AF, particularly in those undergoing coronary artery bypass grafting.

Trend and early outcomes in isolated surgical aortic valve replacement in the United Kingdom

Objective

Surgical aortic valve replacement (SAVR) is traditionally the gold-standard treatment in patients with aortic valve disease. The advancement of transcatheter aortic valve replacement (TAVR) provides an alternative treatment to patients with high surgical risks and those who had previous cardiac surgery. We aim to evaluate the trend, early clinical outcomes, and the choice of prosthesis use in isolated SAVR in the United Kingdom.

Methods

All patients (n = 79,173) who underwent elective or urgent isolated surgical aortic valve replacement (SAVR) from 1996 to 2018 were extracted from the National Adult Cardiac Surgery Audit database. Patients who underwent additional procedures and emergency or salvage SAVR were excluded from the study. Trend and clinical outcomes were investigated in the whole cohort. Patients who had previous cardiac surgery, high-risk groups (EuroSCORE II >4%), and predicted/observed mortality were evaluated. Furthermore, the use of biological prostheses in five different age groups, that are <50, 50-59, 60-69, 70-79, and >80, was investigated. Clinical outcomes between the use of mechanical and biological aortic valve prostheses in patients <65 years old were analyzed.

Results

The number of isolated SAVR increased across the study period with an average of 4,661 cases performed annually after 2010. The in-hospital/30-day mortality rate decreased from 5.28% (1996) to 1.06% (2018), despite an increasing trend in EuroSCORE II. The number of isolated SAVR performed in octogenarians increased from 596 to 2007 (the first year when TAVR was introduced in the UK) to 872 in 2015 and then progressively decreased to 681 in 2018. Biological prosthesis usage increased across all age groups, particularly in the 60-69 group, from 24.59% (1996) to 81.87% (2018). There were no differences in short-term outcomes in patients <65 years old who received biological or mechanical prostheses.

Conclusion

Surgical aortic valve replacement remains an effective treatment for patients with isolated aortic valve disease with a low in-hospital/30-day mortality rate. The number of patients with high-risk and octogenarians who underwent isolated SAVR and those requiring redo surgery has reduced since 2016, likely due to the advancement in TAVR. The use of biological aortic prostheses has increased significantly in recent years in all age groups.

Is EuroSCORE II still a reliable predictor for cardiac surgery mortality in 2022? A retrospective study study

OBJECTIVES

The European System for Cardiac Operation Risk Evaluation II (EuroSCORE II) is the most common tool used to evaluate the perioperative risk of mortality after cardiac surgery in Europe, and its use is currently recommended by the relevant guidelines. However, recently, its role has been questioned: Several papers have suggested that these algorithms may no longer be adequate for risk prediction due to an overestimation of adult cardiac surgical risk. Our goal was to validate the EuroSCORE II in the prediction of 30-day in-hospital mortality in patients undergoing open cardiac surgery in a high-volume hospital.

METHODS

In this retrospective cohort study, we included all patients who underwent cardiac surgery from January 2016 to May 2022 within the departments of cardiac surgery of the Monzino Cardiology Centre in Milan, Italy. We evaluated the discrimination power of the EuroSCORE II by using the receiver operating characteristic curve and the corresponding area under the curve. We performed calibration plots to assess the concordance between the model's prediction and the observed outcomes.

RESULTS

A total of 4,034 patients were included (mean age = 65.1 years; 68% males), of which 674 (16.7%) underwent isolated coronary artery bypass grafting. The EuroSCORE II showed a good discrimination power in predicting 30-day in-hospital mortality (area under the curve = 0.834). However, for interventions performed in an elective setting, very low values of the EuroSCORE II overestimated the observed mortality, whereas for interventions performed in an emergency setting, EuroSCORE II values above 10 extensively underestimated the observed mortality.

CONCLUSIONS

Our study suggests that the EuroSCORE II seems not to be a reliable score in estimating the true risk of death, especially in high-risk patients.

Systematic review and meta-analysis of mortality risk prediction models in adult cardiac surgery

OBJECTIVES

The most used mortality risk prediction models in cardiac surgery are the European System for Cardiac Operative Risk Evaluation (ES) and Society of Thoracic Surgeons (STS) score. There is no agreement on which score should be considered more accurate nor which score should be utilized in each population subgroup. We sought to provide a thorough quantitative assessment of these 2 models.

METHODS

We performed a systematic literature review and captured information on discrimination, as quantified by the area under the receiver operator curve (AUC), and calibration, as quantified by the ratio of observed-to-expected mortality (O:E). We performed random effects meta-analysis of the performance of the individual models as well as pairwise comparisons and subgroup analysis by procedure type, time and continent.

RESULTS

The ES2 {AUC 0.783 [95% confidence interval (CI) 0.765-0.800]; O:E 1.102 (95% CI 0.943-1.289)} and STS [AUC 0.757 (95% CI 0.727-0.785); O:E 1.111 (95% CI 0.853-1.447)] showed good overall discrimination and calibration. There was no significant difference in the discrimination of the 2 models (difference in AUC -0.016; 95% CI -0.034 to -0.002; P = 0.09). However, the calibration of ES2 showed significant geographical variations (P < 0.001) and a trend towards miscalibration with time (P=0.057). This was not seen with STS.

CONCLUSIONS

ES2 and STS are reliable predictors of short-term mortality following adult cardiac surgery in the populations from which they were derived. STS may have broader applications when comparing outcomes across continents as compared to ES2.

REGISTRATION

Prospero (https://www.crd.york.ac.uk/PROSPERO/) CRD42020220983.

Evidence-Based Determination of Cut-Off Points for Increased Cardiac-Surgery Mortality Risk With EuroSCORE II and STS: The Best-Performing Risk Scoring Models in a Single-Centre Australian Population

OBJECTIVES

Risk scoring models (RSMs) are commonly used for estimation of postoperative-mortality risk in patients undergoing cardiac surgery, but their prediction accuracy may vary in different populations and clinical situations. The prognostic accuracies of some RSMs have not yet been fully evaluated in the Australian population. In this retrospective observational study, our aims were to assess the performance of four contemporary RSMs, to identify the best RSMs for prediction of postoperative-mortality in the single-centre cohort, and to determine a statistical threshold for classification of patients with increased or "higher" mortality risk.

METHODS

The study population included patients who underwent cardiac surgery at Liverpool Hospital between January 2013 and December 2014. Demographic information was collected, and mortality risks were estimated with the ES2 (EuroSCORE II), STS (Society of Thoracic Surgeons Score), AS (AusSCORE total) and ASMR (AusSCORE multi-risk) RSMs. (Additive EuroSCORE) (AES) and LES (logistic EuroSCORE) were included for historical interest. Discrimination, the ability to stratify patients between mortality and no mortality outcomes, and calibration, the comparison of risk score estimated and observed outcome in the population, were evaluated for each RSM, to determine their predictive accuracy in the study population. Discrimination was assessed by the AUC (area under the receiver operating characteristic curve), and acceptable calibration by the p-value greater than 0.05 for the Hosmer-Lemeshow (H-L) test. The best AUCs in contempory models were compared using the DeLong test. For ES2 and STS risk scores, cut-off points, or thresholds, for patients at increased risk of mortality were derived using Youden's J-statistics, calculated from sensitivity and specificity of models in predicting mortality.

RESULTS

From a total study population of 898 patients, 738 had scores for all six RSMs. The three EuroSCORE risk models and Youden's J-statistics analysis included the total population. Of the models in contemporary use, ES2 had higher discrimination (AUC=0.850) in this population than ASMR (AUC=0.767, p=0.024) and AS (AUC=0.739) and non-significantly higher discrimination than STS (AUC=0.806, p=0.19). All contemporary models had acceptable calibration but the older LES (H-L p=0.024) did not. Estimated mortality was closest to observed mortality with the ES2 model. Both AES and LES over predicted mortality. The RSM with the highest discrimination in isolated coronary artery bypass graft surgery (CAGs) (AUC=0.847), isolated valves (AUC=0.830), and females (AUC=0.784) was the ES2 model. STS discrimination was highest in CAGs plus valve procedures (AUC 0.891), and males (STS AUC=0.891). Cut-off points for risk scores to define increased risk populations were 3.0% for ES2 and 1.7% for STS. Similar proportions of patients in each RSM (ES2-26% to STS-32%) were defined as higher risk by the model threshold score depending on type of procedure.

CONCLUSION

Among RSMs in contemporary use, ES2 and STS showed the best discrimination and acceptable calibration. Caution is recommended in specific subgroups. Increased mortality risk score cut-off points could be identified for these two RSMs in this single-centre cohort.

Is the EuroSCORE II reliable in surgical mitral valve repair? A single-centre validation study

OBJECTIVES

The EuroSCORE II is widely used to predict 30-day mortality in patients undergoing open and transcatheter cardiac surgery. The aim of this study is to evaluate the discriminatory ability of the EuroSCORE II in predicting 30-day mortality in a large cohort of patients undergoing surgical mitral valve repair in a high-volume centre.

METHODS

A retrospective review of our institutional database was carried on to find all patients who underwent mitral valve repair in our department from January 2012 to December 2019. Discrimination of the EuroSCORE II was assessed using receiver operating characteristic curves. The maximum Youden's Index was employed to define the optimal cut-point. Calibration was assessed by generating calibration plot that visually compares the predicted mortality with the observed mortality. Calibration was also tested with the Hosmer-Lemeshow goodness-of-fit test. Finally, the accuracy of the models was tested calculating the Brier score.

RESULTS

A total of 2645 patients were identified, and the median EuroSCORE II was 1.3% (0.6-2.0%). In patients with degenerative mitral regurgitation (MR), the EuroSCORE II showed low discrimination (area under the curve 0.68), low accuracy (Brier score 0.27) and low calibration with overestimation of the 30-day mortality. In patients with secondary MR, the EuroSCORE II showed a good overall performance estimating the 30-day mortality with good discrimination (area under the curve 0.88), good accuracy (Brier score 0.003) and good calibration.

CONCLUSIONS

In patients with degenerative MR operated on in a high-volume centre with a high level of expertise in mitral valve repair, the EuroSCORE II significantly overestimates the 30-day mortality.

Comparison of the additive, logistic european system for cardiac operative risk (EuroSCORE) with the EuroSCORE 2 to predict mortality in high-risk cardiac surgery

Background:

The aim of this study was to compare the new EuroSCORE (ES) 2 prediction model in high-risk patients with the 2 other oldest additive ES (aES) and logistic ES (lES).

Methods:

Consecutive adult patients undergoing all cardiac surgery except heart transplantation and left ventricular assist device were included. The 3 risk scores were collected before surgery. We defined 4 high-risk groups of patients, patients ≥80 years, combined cardiac surgery, surgery of the thoracic aorta, and emergency cardiac surgery, and 2 low-risk groups, valve surgery and coronary artery bypass surgery. The predicted value of each score has been assessed by the area under the receiver operating characteristics curve (AUC).

Results:

The study had included 3301 patients. Thirty-day mortality was 3.9% (95% confidence interval (CI), 3.3 − 4.6%). The AUC of ES2 was 0.81 (0.77 − 0.84), 0.82 (0.78 − 0.85), 0.70 (0.64 − 0.76), 0.79 (0.74 − 0.83), 0.85 (0.83 − 0.87), and 0.88 (0.86 − 0.90) for octogenarians, thoracic aortic surgery, combined surgery, emergency surgery, coronary surgery, and valve surgery, respectively. These ES2 AUC values were higher than those obtained with the aES for octogenarians, and with the lES for octogenarians and valve surgery. The ES2 calibration was better than the aES and lES calibration for the whole population, and low-risk groups. The ES2 calibration was superior to aES and lES in high-risk groups, except for octogenarians and thoracic aortic surgery compared to lES.

Conclusion:

In high-risk cardiac surgery patients, ES2 only marginally improve the predicted 30-day mortality in comparison to other ES.

Case-mix affects calibration of cardiosurgical severity scores

BACKGROUND

Prognostic models are often used to assess the quality of healthcare. Several scores were developed to predict mortality after cardiac surgery, but none has reached optimal performance in subsequent validations. We validate the most used scores (EUROSCORE I and II, STS, and ACEF) on a cohort of cardiac-surgery patients, assessing their robustness against case-mix changes.

METHODS

The scores were validated on 14,559 patients admitted to 16 Italian cardiosurgical ICUs participating to Margherita-Prosafe project in 2014 and 2015. Calibration was assessed through Hosmer-Lemeshow Test, standardized mortality ratio, and GiViTI calibration test and belt. Discrimination was measured by the area under the ROC curve.

RESULTS

The study included 10,317 patients who were eligible to the calculation of the STS Score (4156 isolated valve, 4681 isolated CABG and 1480 single valve and CABG) which calibrated well in these subgroups. The ACEF Score and EUROSCORE I and II were available for 14,139, and 14,071 patients, respectively. EUROSCORE I significantly overestimated mortality; EUROSCORE II calibrated well overall, but underestimated mortality of patients undergoing complex surgery and non-elective ones. The ACEF Score calibrated poorly in elective and non-elective patients. Discrimination was acceptable for all models (AUC>0.70), but not for the ACEF Score.

CONCLUSIONS

Cardiac surgery scores calibrate poorly when the case-mix of validation and development samples differs. To grant reliability for benchmarking, they should be validated in the clinical settings on which they are applied and updated periodically. Advanced statistical tools are essential for the correct interpretation and application of severity scores.

Outcomes of open heart surgery in patients with end-stage renal disease

Background

Cardiovascular diseases of chronic dialysis patients are often undertreated because of their higher surgical risk. This study aimed to assess mortality and morbidity after open heart surgery in chronic dialysis patients compared to those with normal renal function and identify risk factors for postoperative outcomes.

Methods

We retrospectively analyzed 2,432 patients who underwent open heart surgery from 2002 to 2017 and collected data from 116 patients (38 patients on dialysis and 78 age-, sex-, and diabetes mellitus status-matched control patients with normal kidney function). We assessed comorbidities, New York Heart Association (NYHA) class, laboratory data, surgical methods, and postoperative outcomes.

Results

The dialysis group had more comorbidities, higher NYHA classes, and greater need for urgent surgeries compared to the control group. They exhibited significantly higher postoperative mortality (18.4% vs. 2.6%, P = 0.005) and more overall complications (65.8% vs. 25.6%, P < 0.001). Dialysis itself significantly increased relative risk for inhospital mortality after adjustment. EuroSCORE II was not as useful as in the general population. Multivariate logistic regression analysis demonstrated that total (adjusted odds ratio [AOR], 10.7; P = 0.029) and in-hospital death risk (AOR, 14.7; P = 0.033), the durations of postoperative hospitalization (AOR, 4.6; P = 0.034), CRRT (AOR 36.8; P = 0.004), and ventilator use (AOR, 7.6; P = 0.022) were significantly increased in the dialysis group.

Conclusion

The dialysis group exhibited a higher risk for mortality and overcall complications after open heart surgery compared to the patients with normal renal function. Therefore, the benefit of surgical treatment must be balanced against potential risks.

Incremental Predictive Value of Longitudinal Axis Strain and Late Gadolinium Enhancement Using Standard CMR Imaging in Patients with Aortic Stenosis

To analyse the predictive ability and incremental value of left ventricular longitudinal axis strain (LAS) and late gadolinium enhancement (LGE) using standard cardiovascular magnetic resonance (CMR) imaging for the diagnosis and prognosis of severe aortic stenosis (AS) in patients with an indication for aortic valve replacement. We conducted a prospective study on 52 patients with severe AS and 52 volunteers. The evaluation protocol included standard biochemistry tests, novel biomarkers of myocardial fibrosis, 12-lead electrocardiograms and 24-hour Holter, the 6-minute walk test and extensive echocardiographic and CMR imaging studies. Outcomes were defined as the composite of major cardiovascular events (MACEs). Among AS patients, most (n = 17, 77.2%) of those who exhibited LGE at CMR imaging had MACEs during follow-up. Kaplan–Meier curves for event-free survival showed a significantly higher rate of MACEs in patients with LGE (p < 0.01) and decreased LAS (p < 0.001). In Cox regression analysis, only reduced LAS (hazard ratio 1.33, 95% CI (1.01 to 1.74), p < 0.01) and the presence of LGE (hazard ratio 11.3, 95% CI (1.82 to 70.0), p < 0.01) were independent predictors for MACEs. The predictive value increased if both LGE and reduced LAS were added to left ventricular ejection fraction (LVEF). None of the biomarkers of increased collagen turnover exhibited any predictive value for MACEs. LAS by CMR is an independent predictor of outcomes in patients with AS and provides incremental value beyond the assessment of LVEF and the presence of LGE.

sST2 as a novel biomarker for the prediction of in-hospital mortality after coronary artery bypass grafting

Objectives: Soluble suppression of tumorigenicity 2 (sST2) biomarker is an emerging predictor of adverse clinical outcomes, but its prognostic value for in-hospital mortality after coronary artery bypass grafting (CABG) is not well understood. This study measured the association between operative sST2 levels and in-hospital mortality after CABG. Methods: A prospective cohort of 1560 CABG patients were analyzed from the Northern New England Cardiovascular Disease Study Group Biomarker Study. The primary outcome was in-hospital mortality after CABG surgery (n = 32). Results: After risk adjustment, patients in the third tercile of pre-, post- and pre-to-postoperative sST2 values experienced significantly greater odds of in-hospital death compared to patients in the first tercile of sST2 values. The addition of both postoperative and pre-to-postoperative sST2 biomarker significantly improved ability to predict in-hospital mortality status following CABG surgery, compared to using the EuroSCORE II mortality model alone, (c-statistic: 0.83 [95% CI: 0.75, 0.92], p value 0.0213) and (c-statistic: 0.83 [95% CI: 0.75, 0.92], p value 0.0215), respectively. Conclusion: sST2 values are associated with in-hospital mortality after CABG surgery and postoperative and pre-to-post operative sST2 values improve prediction. Our findings suggest that sST2 can be used as a biomarker to identify adult patients at greatest risk of in-hospital death after CABG surgery.

Validation of EuroSCORE II in patients undergoing coronary artery bypass grafting (CABG) surgery at the National Heart Institute, Kuala Lumpur: a retrospective review

Background: The European System for Cardiac Operative Risk (EuroSCORE) II was developed in 2011 to replace the aging EUROScore for predicting in-house mortality after cardiac surgery. Our aim was to validate EuroSCORE II in Malaysian patients undergoing coronary artery bypass graft (CABG) surgery at our Institute. Methods: A retrospective single-center study was performed. A database was created to include EuroSCORE II values and actual mortality of 1718 patients undergoing CABG surgery in Malaysia from 1st January to 31st December 2016. The goodness-of-fit of EuroSCORE II was determined by the Hosmer-Lemeshow goodness-of-fit test and discriminatory power with the areas under the receiver operating characteristics (ROC) curve (AUC). Results: Observed mortality rate was 4.66% (80 out of 1718 patients). The median EuroSCORE II value was 2.06% (Inter Quartile Range: 1.94%) (1st quartile: 1.45%, 3rd quartile: 3.39%). The AUC for EuroSCORE II was 0.7 (95% CI 0.640 - 0.759) indicating good discriminatory power. The Hosmer-Lemeshow goodness-of-fit test did not show significant difference between expected and observed mortality in accordance to the EuroSCORE II model (Chi-square = 13.758, p = 0.089) suggesting good calibration of the model in this population. Cross-tabulation analysis showed that there is slight overestimation of EuroSCORE II in low-risk groups (0-10%) and slight underestimation in high-risk groups (>20%). Multivariate logistic regression analysis showed that gender, age, total hospital stay, serum creatinine and critical pre-operative state are significant predictors of mortality post-CABG surgery. Conclusion: This study indicated that the EuroSCORE II is a good predictor of post-operative mortality in the context of Malaysian patients undergoing CABG surgery. Our study also showed that certain independent variables might possess higher weightage in predicting mortality among this patient group. Therefore, it is suggested that EuroSCORE II can be safely used for risk assessment while ideally, clinical consideration should be applied on an individual basis.

Validation of EuroSCORE II in patients undergoing coronary artery bypass grafting (CABG) surgery at the National Heart Institute, Kuala Lumpur: a retrospective review

Background: The European System for Cardiac Operative Risk (EuroSCORE) II was developed in 2011 to replace the aging EUROScore for predicting in-house mortality after cardiac surgery. Our aim was to validate EuroSCORE II in Malaysian patients undergoing coronary artery bypass graft (CABG) surgery at our Institute. Methods: A retrospective single-center study was performed. A database was created to include EuroSCORE II values and actual mortality of 1718 patients undergoing CABG surgery in Malaysia from 1st January to 31st December 2016. The goodness-of-fit of EuroSCORE II was determined by the Hosmer-Lemeshow goodness-of-fit test and discriminatory power with the areas under the receiver operating characteristics (ROC) curve (AUC). Results: Observed mortality rate was 4.66% (80 out of 1718 patients). The median EuroSCORE II value was 2.06% (Inter Quartile Range: 1.94%) (1st quartile: 1.45%, 3rd quartile: 3.39%). The AUC for EuroSCORE II was 0.7 (95% CI 0.640 - 0.759) indicating good discriminatory power. The Hosmer-Lemeshow goodness-of-fit test did not show significant difference between expected and observed mortality in accordance to the EuroSCORE II model (Chi-square = 13.758, p = 0.089) suggesting good calibration of the model in this population. Cross-tabulation analysis showed that there is slight overestimation of EuroSCORE II in low-risk groups (0-10%) and slight underestimation in high-risk groups (>20%). Multivariate logistic regression analysis showed that gender, age, total hospital stay, serum creatinine and critical pre-operative state are significant predictors of mortality post-CABG surgery. Conclusion: This study indicated that the EuroSCORE II is a good predictor of post-operative mortality in the context of Malaysian patients undergoing CABG surgery. Our study also showed that certain independent variables might possess higher weightage in predicting mortality among this patient group. Therefore, it is suggested that EuroSCORE II can be safely used for risk assessment while ideally, clinical consideration should be applied on an individual basis.

Risk analysis of dialysis-dependent patients who underwent coronary artery bypass grafting: Effects of dialysis modes on outcomes

Cardiovascular disease is the major morbidity and leading cause of mortality for dialysis-dependent patients. This study aimed to stratify the risk factors and effects of dialysis modes in relation to coronary artery bypass grafting (CABG) surgery among dialysis-dependent patients.This retrospective study enrolled dialysis-dependent patients who underwent CABG from October 2005 to January 2015. All data of demographics, medical history, surgical details, postoperative complications, and in-hospital mortality were analyzed, and patients were categorized as those with or without in-hospital mortality and those with preoperative hemodialysis (HD) or peritoneal dialysis (PD).Of 134 enrolled patients, 25 (18.7%) had in-hospital mortality. Multivariate analyses identified that older age [odds ratio (OR): 1.110, 95% confidence interval (CI): 1.030-1.197, P = .006], previous stroke history (OR: 5.772, 95% CI: 1.643-20.275, P = .006), PD (OR: 19.607, 95% CI: 3.676-104.589, P < .001), and emergent operation (OR: 8.788, 95% CI: 2.697-28.636, P < .001) were statistically significant risk factors for in-hospital mortality among dialysis-dependent patients with CABG surgery. Patients with PD had a higher in-hospital mortality rate (58.3% vs 14.8%, P < .001) and lower 1-year overall survival (33.3% vs 56.6%, P = .031) than did HD patients. The major in-hospital mortality cause was cardiac events among HD patients and septic shock among PD patients.Among dialysis patients who received CABG, those with older age, previous stroke history, PD, and emergent operation had higher risks. Those with PD were prone to poorer in-hospital outcomes after CABG surgery.

Assessment of Euroscore and SAPS III as hospital mortality predicted in cardiac surgery

OBJECTIVES

To perform an external validation of Euroscore I, Euroscore II and SAPS III.

PATIENTS AND METHOD

Retrospective cohort study over three years on all adult patients who underwent cardiac surgery. We reviewed the clinical data, following the patient until outcome or discharge from hospital (dead, alive). We computed the predicted mortality by Euroscore I (EI), II (EII) and SAPS III. The model validation was assessed by discrimination: area under curve ROC; and calibration (Hosmer-Lemeshow test).

RESULTS

866 patients were included. 62.5% of them male, with a median age of 69 years, 6.1% died during hospitalization. Predicted mortality: E I 7.94%, E II 3.54, SAPS III 12.1%. Area under curve (95% IC): E I 0.862 (0.812-0.912); E II 0.861 (0.806-0.915); SAPS III 0.692 (0.601-0.784). Hosmer-Lemeshow test: E I 14.0046 (P=.08164); E II 33.67 (P=.00004660); SAPS III 11.57 (P=.171).

CONCLUSIONS

EII had good discrimination, but the calibration was not good with predicted mortality lower than the real mortality. E I showed the best discrimination with good calibration and a tendency to overestimate the mortality. SAPS III showed poor discrimination with good calibration and a tendency to greatly overestimate the predicted mortality. We saw no improvement in the predictive performance of EII over I and we reject the use of SAPS III in this kind of patient.

Emergency Coronary Artery Bypass Grafting: Indications and Outcomes from 2003 through 2013

Emergency coronary artery bypass grafting (CABG) is associated with increased in-hospital mortality rates and adverse events. This study retrospectively evaluated indications and outcomes in patients who underwent emergency CABG. The Society of Thoracic Surgeons database for a single center (Jewish Hospital) was queried to identify patients undergoing isolated CABG. Univariate analysis was performed. From January 2003 through December 2013, 5,940 patients underwent CABG; 212 presented with emergency status. A high proportion of female patients (28.2%) underwent emergency surgery. Emergency CABG patients experienced high rates of intra-aortic balloon pump support, bleeding, dialysis, in-hospital death, and prolonged length of stay. The proportion of emergency coronary artery bypass grafting declined during years 2008-2013 compared with 2003-2007 (2.2% vs. 4.5%, P < 0.001), but the incidence of angiographic accident (5.3% vs. 29.2%) increased as an indication. Ongoing ischemia remains the most frequent indication for emergency CABG, yet the incidence of angiographic accident has greatly increased. In-hospital mortality rates and adverse events remain high. If we look specifically at emergency CABG cases arising from angiographic accident, we find that 14 (15%) of all 93 emergency CABG deaths occurred in that subset of patients. Efforts to improve outcomes should therefore be focused on this high-risk group.

In search of the ideal risk-scoring system for very high-risk cardiac surgical patients: a two-stage approach

Background

Cardiac surgery patients at very high risk are difficult to stratify with the existing risk scores. The objective of this study is to assess the clinical performance of two existing risk stratification scores (EuroSCORE II and ACEF score) in the setting of very high-risk patients undergoing cardiac surgery, and to identify a possible strategy to better address this patient population.

Methods

Three-thousand-four-hundred-twenty eight (3,428) consecutive adult patients receiving cardiac operations at a single institution were investigated. Patients having an operative mortality risk >25 % at either the EuroSCORE II or the ACEF score were selected (105 patients). The discrimination power and calibration of the EuroSCORE II and the ACEF score were investigated. Factors associated with operative mortality were included in a multivariable logistic regression model and a new model was re-built for this patient population.

Results

The observed mortality rate was 26 %. The expected mortality rate was underestimated by the EuroSCORE II (16 %) and overestimated by the ACEF Score (36 %). The EuroSCORE maintained a good discrimination (c-statistics 0.75) while the ACEF score did not (c-statistics 0.52). Within this patient population, the independent risk factors for operative mortality were emergency surgery, serum creatinine levels, pulmonary hypertension, and preoperative anemia. A model based on these factors provided an expected mortality risk of 26 % with a good discrimination (c-statics 0.82). Applying this model to extremely high-risk patients (expected mortality rate > 50 %) resulted in the re-classification of 25 % of the patient population.

Conclusions

The existing risk models have a poor clinical relevance in the segment of patients at very high mortality risk. This is particularly frustrating, because these patients are those where the decision-making process is more important. A two-stage classification strategy (first stage: EuroSCORE II/ACEF score risk > 25 %; second stage: reclassification based on pulmonary hypertension, serum creatinine, and anemia) seems a possible strategy to correctly address very high-risk patients.

Risk Stratification in Off-Pump Coronary Artery Bypass (OPCAB) Surgery—Role of EuroSCORE II

OBJECTIVES

To evaluate the EuroSCORE II for risk stratification in patients undergoing off-pump coronary artery bypass (OPCAB) surgery.

DESIGN

A retrospective observational study.

SETTING

Two tertiary care hospitals.

PARTICIPANTS

Participants were 1,211 patients undergoing OPCAB surgery.

INTERVENTIONS

No interventions were implemented.

MEASUREMENTS AND MAIN RESULTS

The EuroSCORE II estimated the operative risk for each patient. The calibration of the scoring system was assessed using the Hosmer Lemeshow test, and the discriminative capacity was estimated with area under receiver operating characteristic curves. The incidence, patient characteristics, causes of intraoperative conversion to on-pump coronary artery bypass (ONCAB), and outcome were studied. The all-cause in-hospital mortality was 2.39%. Predicted mortality with the EuroSCORE II was 2.03±1.63. Using the Hosmer Lemeshow test, a C statistic of 8.066 (p = 0.472) was obtained, indicating satisfactory model fit. The calculated area under the receiver operating characteristic curve was 0.706 (p = 0.0002), indicating good discriminatory power. Emergency intraoperative conversion to ONCAB occurred in 6.53% of patients. The mortality in the ONCAB group was significantly higher compared with patients who underwent successful OPCAB surgery (15.18% v 1.5%, p<0.0001). On multiple regression analysis with conversion to ONCAB as the endpoint, associated factors were patients with a higher EuroSCORE II (odds ratio = 1.13, confidence interval = 1.03-1.27) and more-than-trivial mitral regurgitation (odds ratio = 1.84, confidence interval = 1.07-3.06). Net reclassification improvement of 0.714 (p<0.0001) was obtained when on-pump conversion was added to the EuroSCORE II.

CONCLUSIONS

The EuroSCORE II has satisfactory calibration and discrimination power to predict mortality after OPCAB surgery. Intraoperative conversion to ONCAB is a major complication of OPCAB surgery. A higher EuroSCORE II also predicts higher probability of conversion to ONCAB.

Risk factors and outcome analysis after surgical management of ventricular septal rupture complicating acute myocardial infarction: a retrospective analysis

BACKGROUND

Ventricular septal rupture (VSR) is an uncommon but well-recognized mechanical complication of acute myocardial infarction (AMI). The outcome of VSR remains poor even in the era of reperfusion therapy. We reviewed our experience with surgical repair of post-infarction VSR and analyzed outcomes in an attempt to identify prognostic factors.

METHODS

From October 1995 to December 2013, data from 47 consecutive patients (mean age, 68 ± 9.5 years) with post-infarction VSR who underwent surgical repair at our institute were retrospectively reviewed. The preoperative conditions, morbidity and surgical mortality were analyzed. Multivariate analysis was subsequently carried out by constructing a logistic regression model in order to identify independent predictors of postoperative mortality. Long term survival function were estimated using the Kaplan-Meier method and compared using the log-rank test.

RESULTS

Percutaneous coronary intervention was performed in 17 (36.2%) patients, intra-aortic balloon pump (IABP) was used in 34 (72.3%), and six (12.8%) were supported with extracorporeal membrane oxygenation (ECMO) preoperatively. Forty-one (87.2%) patients received emergent surgical treatment. Concomitant coronary artery bypass grafting was performed in 27 (57.4%) patients. Operative mortality was 36.2% (17 of 47). The survival rate was 59.3% with concomitant CABG and 70% without concomitant CABG (p = 14). Multivariate analysis revealed that the survivors had higher preoperative left ventricular ejection fractions (LVEFs) compared with those who died (51 ± 13.7% vs. 36.6 ± 6.4% , respectively; p < 0.001) and lower European system for cardiac operative risk evaluation II (EuroSCORE II) (22.9 ± 14.9 vs. 38.3 ± 13.9, respectively; p < 0.001). The patients receiving total revascularization has long term survival benefit (p = 0.028).

CONCLUSIONS

Post-infarction VSR remains a serious and challenging complication of AMI in the modern surgical era. The EuroSCORE II can be used for an approximate prediction of operative mortality. Preserved LVEF was associated with better prognosis, while the need for postoperative RRT was associated with higher early and late mortality. Besides, the strategy of total revascularization should be applied to ensure long-term survival benefit.

Validation of the Intensive Care National Audit and Research Centre Scoring System in a UK Adult Cardiac Surgery Population

OBJECTIVE

The Intensive Care National Audit and Research Centre (ICNARC) scoring system was conceived in 2007, utilizing 12 physiologic variables taken from the first 24 hours of adult admissions to the general intensive care unit (ICU) to predict in-hospital mortality. The authors aimed to evaluate the ICNARC score in predicting mortality in cardiac surgical patients compared to established cardiac risk models such as logistic EuroSCORE as well as to the Acute Physiology and Chronic Health Evaluation (APACHE) II.

DESIGN

Retrospective analysis of data collected prospectively.

SETTING

Single-center study in a cardiac intensive care in a regional cardiothoracic center.

PARTICIPANTS

Patients undergoing cardiac surgery between January 2010 and June 2012.

METHODS

A total of 1,646 patients were scored preoperatively using the logistic EuroSCORE and postoperatively using ICNARC and APACHE II. Data for comparison of scoring systems are presented as area under the receiver operating characteristic curve.

MEASUREMENTS AND MAIN RESULTS

The mean age at surgery was 67 years±10.1. The mortality from all cardiac surgery was 3.2%. The mean logistic EuroSCORE was 7.31±10.13, the mean ICNARC score was 13.42±5.055, while the mean APACHE II score was 6.32±7.731. The c-indices for logistic EuroSCORE, ICNARC, and APACHE II were 0.801, 0.847 and 0.648, respectively.

CONCLUSION

The authors have, for the first time, validated the ICNARC score as a useful predictor of postoperative mortality in adult cardiac surgical patients. This could have implications for postoperative management, focusing the utilization of resources as well as a method to measure and compare performance in the cardiothoracic ICU.

Performance of InsCor and three international scores in cardiac surgery at Santa Casa de Marília

OBJECTIVE

To apply and to compare the Society of Thoracic Surgery score (STS), EuroSCORE (Eurosc1), EuroSCORE II (Eurosc2) and InsCor (IS) for predicting mortality in patients undergoing to coronary artery bypass graft and/or valve surgery at the Santa Casa Marilia.

METHODS

The present study is a cohort. It is a prospective, observational, analytical and unicentric. We analyzed 562 consecutive patients coronary artery bypass graft and/or valve surgery, between April 2011 and June 2013 at the Santa Casa Marilia. Mortality was calculated for each patient through the scores STS, Eurosc1, Eurosc2 and IS. The calibration was calculated using the Hosmer Lemeshow test and discrimination by ROC curve.

RESULTS

The hospital mortality was 4,6%. The calibration is generally adequate group P=0.345, P=0.765, P=0.272 and P=0.062 for STS, Eurosc1, Eurosc2, and IS respectively. The discriminatory power of STS score 0.649 (95% CI 0.529 to 0.770, P=0.012), Eurosc1 0.706 (95% CI 0.589 to 0.823, P ≤0.001), Eurosc2 was 0.704 (95% CI 0.590-0.818 P=0.001) and InsCor 0.739 (95% CI 0.638 to 0.839, P ≤0.001).

CONCLUSION

We can say that overall, the InsCor was the best model, mainly in the discrimination of the sample. The InsCor showed good accuracy, in addition to being effective and easy to apply, especially by using a smaller number of variables compared to the other models.