Dynamics in cardiac surgery: trends in population characteristics and the performance of the EuroSCORE II over time.

OBJECTIVES: The aim of this study was to investigate the performance of the EuroSCORE II over time and dynamics in values of predictors included in the model. METHODS: A cohort study was performed using data from the Netherlands Heart Registration. All cardiothoracic surgical procedures performed between 1 January 2013 and 31 December 2019 were included for analysis. Performance of the EuroSCORE II was assessed across 3-month intervals in terms of calibration and discrimination. For subgroups of major surgical procedures, performance of the EuroSCORE II was assessed across 12-month time intervals. Changes in values of individual EuroSCORE II predictors over time were assessed graphically. RESULTS: A total of 103 404 cardiothoracic surgical procedures were included. Observed mortality risk ranged between 1.9% [95% confidence interval (CI) 1.6-2.4] and 3.6% (95% CI 2.6-4.4) across 3-month intervals, while the mean predicted mortality risk ranged between 3.4% (95% CI 3.3-3.6) and 4.2% (95% CI 3.9-4.6). The corresponding observed:expected ratios ranged from 0.50 (95% CI 0.46-0.61) to 0.95 (95% CI 0.74-1.16). Discriminative performance in terms of the c-statistic ranged between 0.82 (95% CI 0.78-0.89) and 0.89 (95% CI 0.87-0.93). The EuroSCORE II consistently overestimated mortality compared to observed mortality. This finding was consistent across all major cardiothoracic surgical procedures. Distributions of values of individual predictors varied broadly across predictors over time. Most notable trends were a decrease in elective surgery from 75% to 54% and a rise in patients with no or New York Heart Association I class heart failure from 27% to 33%. CONCLUSIONS: The EuroSCORE II shows good discriminative performance, but consistently overestimates mortality risks of all types of major cardiothoracic surgical procedures in the Netherlands.

Essential Surgical Plan Modifications After Virtual Reality Planning in 50 Consecutive Segmentectomies.

BACKGROUND: Lately, increased interest in pulmonary segmentectomy has been observed. Segmental border identification is extremely difficult on 2-dimensional computed tomography (CT). Preoperative application of virtual reality (VR) can provide better insight into patient-specific anatomy. The aim of this study was to investigate the added clinical value of 3-dimensional (3D) VR using PulmoVR for preoperative planning. METHODS: Patients with an indication for pulmonary segmentectomy were included between June 2020 and September 2021 at the Erasmus Medical Center, Rotterdam, The Netherlands. CT scans were (semi)automatically segmented to visualize lung segments, segmental arteries, veins, and bronchi. Three surgeons made a surgical plan on the basis of the conventional CT scan and subsequently analyzed the VR visualization. The primary outcome was the incidence of critical (ensuring radical resection) preoperative plan modifications. Secondarily, data on observed anatomic variation and perioperative (oncologic) outcomes were collected. RESULTS: A total of 50 patients (median age at surgery, 65 years [interquartile range, 17.25 years]) with an indication for pulmonary segmentectomy were included. After supplemental VR visualization, the surgical plan was adjusted in 52%; the tumor was localized in a different segment in 14%, more lung-sparing resection was planned in 10%, and extended segmentectomy, including 1 lobectomy, was planned in 28%. Pathologic examination confirmed radical resection in 49 patients (98%). CONCLUSIONS: This 3D VR technology showed added clinical value in the first 50 VR-guided segmentectomies because a 52% change of plan with 98% radical resection was observed. Furthermore, 3D VR visualization of the bronchovasculature, including various anatomic variations, provided better insight into patient-specific anatomy and offered lung-sparing possibilities with more certainty.

Methods for updating a risk prediction model for cardiac surgery: a statistical primer.

Risk prediction models in cardiac surgery tend to lose their predictive performance over time. This statistical primer aims to provide an overview of updating methods with their strengths and weaknesses. This is important, as model updating may be an efficient and good alternative to the de novo development of risk models. The discussed methods are intercept recalibration, logistic recalibration, model revision, closed test procedure and Bayesian modelling. It is recommended to report an updated model according to the transparent reporting of a multivariable prediction model for individual prognosis or diagnosis (TRIPOD) statement and to include calibration and discrimination plots of the original and updated models to assess the model performance. An example is provided for updating the EuroSCORE II model in a national cohort from the Netherlands. Logistic recalibration results in a significant improvement of model performance, without the risk of overfitting. The example illustrates that more data allow for more extensive updating methods.

Developing a Quality Standard for Verbal Communication During CABG Procedures.

Verbal communication during coronary artery bypass graft (CABG) procedures is essential for safe and efficient cardiac surgery, yet sensitive to failure due to a current lack of standardization. The goal of this study was to improve communication during CABG by identifying critical items in verbal interaction between surgeons, anesthetists, and perfusionists. Based on 6 video recordings, a list was assembled containing items of communication in CABG procedures. Personal interviews and a consecutive focus group meeting with surgeons, anesthetists, and perfusionists revealed which of these items were considered critical. Afterward, the recordings were systematically analyzed on the communication of these critical items. Practitioners considered 64 items to be critical to verbally communicate for safe CABG surgery. On average, these critical items were verbalized in 4.4 out of 6 recorded CABGs. Observations also show that the surgical subteam is the most verbally active subteam and the initiator of the majority of all exchanges. The exchange type involved was mainly "direction" and "status." The majority of communication during critical events is between 2 subteams and occurs in the form of call-back loops. Over half of the call-backs are substantive and communication is rarely directed at a specific team member by name. In this study, a list was developed containing 64 items that practitioners unanimously considered critical to verbalize during a CABG procedure. It forms the foundation of a quality standard for verbal communication during cardiopulmonary bypass (CPB) and can increase safety and efficiency of cardiac surgery.

Male-female differences in aortic valve and combined aortic valve/coronary surgery: a national cohort study in the Netherlands.

Objective: The outcome of female patients after adult cardiac surgery has been reported to be less favourable compared with the outcome of male patients. This study compares men with women with respect to patient and procedural characteristics and early mortality in a contemporary national cohort of patients who underwent aortic valve (AV) and combined aortic valve/coronary (CABG/AV) surgery. Methods: All patients who underwent AV (n=8717, 56% male) or a combined CABG/AV surgery (n=5867, 67% male) in the Netherlands between January 2007 and December 2011 were included. Results: In both groups, women were generally older than men (p<0.001) and presented with higher logistic EuroSCORES. In isolated AV surgery, men and women had comparable in-hospital mortality (OR 1.20, 95% CI 0.90 to 1.61; p=0.220). In concomitant CABG/AV surgery, in-hospital mortality was higher in women compared with men (OR 2.00, 95% CI 1.44 to 2.79; p<0.001). The area under the curve for logistic EuroSCORE 1 was systematically higher for men versus women in isolated AV surgery 0.82 (95% CI 0.78 to 0.86) vs 0.75 (95% CI 0.69 to 0.80) and in concomitant CABG/AV surgery 0.78 (95% CI 0.73 to 0.82) vs 0.69 (95% CI 0.63 to 0.74). Finally, (the weight of) risk factors associated with in-hospital mortality differed between men and women. Conclusions: There are substantial male-female differences in patient presentation and procedural aspects in isolated AV and concomitant CABG/AV surgery in the Netherlands. Further studies are necessary to explore the mechanisms underlying the observed differences. In addition, the observation that standard risk scores perform worse in women warrants exploration of male-female specific risk models for patients undergoing cardiac surgery.Brief title.

Male-female differences and survival in patients undergoing isolated mitral valve surgery: a nationwide cohort study in the Netherlands.

OBJECTIVES: The objective of this study was to compare male-female differences with respect to baseline characteristics and short-term outcome in a contemporary nationwide cohort of patients who underwent isolated mitral valve (MV) surgery. METHODS: All patients [N = 3411; 58% males (N = 1977)] who underwent isolated MV surgery (replacement: N = 1048, 31%; reconstruction: N = 2364, 69%) in the Netherlands between January 2007 and December 2011 were included in this study. Differences in patient and procedural characteristics and in-hospital outcome were compared between male and female patients. RESULTS: Female patients were generally older (mean age, 64 vs 61 years, P < 0.001), presented more often with pulmonary hypertension (P = 0.03) and had higher logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) I (P < 0.001). Male patients presented more often with prior coronary artery bypass graft surgery (P < 0.001) and active endocarditis (P = 0.002). Female patients underwent MV replacement more often (P < 0.001) and, in case of replacement, received stented bioprostheses more often (P < 0.001). In-hospital mortality rates after MV replacement were 7% (n = 33) and 7% (n = 40) in male and female patients, respectively (OR 1.08, 95% CI 0.67-1.75; P = 0.75). In-hospital mortality rates after MV reconstruction were 1.4% (n = 21) and 1.3% (n = 11) in male and female patients, respectively (OR 0.88, 95% CI 0.42-1.84; P = 0.74). CONCLUSIONS: There are substantial male-female differences in patient presentation and procedural aspects in isolated MV surgery in the Netherlands. Female patients are older, have more severe disease at the time of surgery and undergo valve repair less often. Future studies are needed to identify potentially modifiable patient factors to improve the outcome of female patients with MV disease.

Improved Prediction by Dynamic Modeling: An Exploratory Study in the Adult Cardiac Surgery Database of the Netherlands Association for Cardio-Thoracic Surgery.

BACKGROUND: The predictive performance of static risk prediction models such as EuroSCORE deteriorates over time. We aimed to explore different methods for continuous updating of EuroSCORE (dynamic modeling) to improve risk prediction. METHODS AND RESULTS: Data on adult cardiac surgery from 2007 to 2012 (n=95 240) were extracted from the Netherlands Association for Cardio-Thoracic Surgery database. The logistic EuroSCORE predicting in-hospital death was updated using 6 methods: recalibrating the intercept of the logistic regression model; recalibrating the intercept and joint effects of the prognostic factors; re-estimating all prognostic factor effects, re-estimating all prognostic factor effects, and applying shrinkage of the estimates; applying a test procedure to select either of these; and a Bayesian learning strategy. Models were updated with 1 or 3 years of data, in all cardiac surgery or within operation subgroups. Performance was tested in the subsequent year according to discrimination (area under the receiver operating curve, area under the curve) and calibration (calibration slope and calibration-in-the-large). Compared with the original EuroSCORE, all updating methods resulted in improved calibration-in-the-large (range -0.17 to 0.04 versus -1.13 to -0.97, ideally 0.0). Calibration slope (range 0.92-1.15) and discrimination (area under the curve range 0.83-0.87) were similar across methods. In small subgroups, such as aortic valve replacement and aortic valve replacement+coronary artery bypass grafting, extensive updating using 1 year of data led to poorer performance than using the original EuroSCORE. The choice of updating method had little effect on benchmarking results of all cardiac surgery. CONCLUSIONS: Several methods for dynamic modeling may result in good discrimination and superior calibration compared with the original EuroSCORE. For large populations, all methods are appropriate. For smaller subgroups, it is recommended to use data from multiple years or a Bayesian approach.

Trends and outcomes of valve surgery: 16-year results of Netherlands Cardiac Surgery National Database.

OBJECTIVES: The aim was to describe procedural volumes, patient risk profile and outcomes of heart valve surgery in the past 16 years in Netherlands. METHODS: The Dutch National Database for Cardio-Thoracic Surgery includes approximately 200 000 cardiac operations performed between 1995 and 2010. Information on all valve surgeries (56 397 operations) was extracted. We determined trends for changes in procedural volume, demographics, risk profile and in-hospital mortality of valve operations. Because of incomplete data in the first years of registration, the total number of operations in those years was estimated using Poisson regression. For a subset from 2007 to 2010, follow-up data were available. Survival status was obtained through linkage with the national Cause of Death Registry, and survival analysis was performed using Kaplan-Meier method. Information on discharge and readmissions was obtained from the National Hospital Discharge Registry. RESULTS: The annual volume of heart valve operations increased by more than 100% from an estimated 2431 in 1995 to 5906 in 2010. Adjusted for population size in Netherlands, the number of operations per 100 000 adults increased from 20 in 1995 to 43 in 2010. In 2010, frequently performed valve surgery included the following: 34.6% isolated aortic valve (AoV) replacement, 21.8% AoV replacement and coronary artery bypass grafting (CABG), 14.6% isolated mitral valve surgery (repair or replacement) and 9.1% mitral valve and CABG. In AoV surgery, an increasing use of bioprostheses in all age categories is observed. In mitral valve surgery, 75.4% was performed by repair rather than replacement in 2010. In-hospital mortality for all valve surgery decreased significantly from 4.6% in 2007 to 3.6% in 2010, whereas the mean logistic EuroSCORE remained stable (median 5.8, P = 1.000). Thirty-day mortality after all valve surgery was 3.9% and 120-day mortality was 6.5%. At 1 year, survival after all valve surgery was 91.6% and a reoperation had been performed in 1.6%. The median postoperative length of stay was 7 days (interquartile range (IQR) 5-11) in the primary hospital and 11 days (IQR 8-16), including subsequent stay, in the secondary hospital. CONCLUSIONS: The results of this study provide a comprehensive overview of valve surgery trends and outcomes in Netherlands. The number of heart valve operations performed in Netherlands has increased since 1995. The significant decrease in mortality and unchanged EuroSCORE between 2007 and 2010 might reflect a general improvement of the safety of valve surgery.

Evaluation of cardiac surgery mortality rates: 30-day mortality or longer follow-up?

OBJECTIVES: The aim of our study was to investigate early mortality after cardiac surgery and to determine the most adequate follow-up period for the evaluation of mortality rates. METHODS: Information on all adult cardiac surgery procedures in 10 of 16 cardiothoracic centres in Netherlands from 2007 until 2010 was extracted from the database of Netherlands Association for Cardio-Thoracic Surgery (n = 33 094). Survival up to 1 year after surgery was obtained from the national death registry. Survival analysis was performed using Kaplan-Meier and Cox regression analysis. Benchmarking was performed using logistic regression with mortality rates at different time points as dependent variables, the logistic EuroSCORE as covariate and a random intercept per centre. RESULTS: In-hospital mortality was 2.94% (n = 972), 30-day mortality 3.02% (n = 998), operative mortality 3.57% (n = 1181), 60-day mortality 3.84% (n = 1271), 6-month mortality 5.16% (n = 1707) and 1-year mortality 6.20% (n = 2052). The survival curves showed a steep initial decline followed by stabilization after ∼60-120 days, depending on the intervention performed, e.g. 60 days for isolated coronary artery bypass grafting (CABG) and 120 days for combined CABG and valve surgery. Benchmark results were affected by the choice of the follow-up period: four hospitals changed outlier status when the follow-up was increased from 30 days to 1 year. In the isolated CABG subgroup, benchmark results were unaffected: no outliers were found using either 30-day or 1-year follow-up. CONCLUSIONS: The course of early mortality after cardiac surgery differs across interventions and continues up to ∼120 days. Thirty-day mortality reflects only a part of early mortality after cardiac surgery and should only be used for benchmarking of isolated CABG procedures. The follow-up should be prolonged to capture early mortality of all types of interventions.

Data Resource Profile: adult cardiac surgery database of the Netherlands Association for Cardio-Thoracic Surgery.

In 2007 The Netherlands Association for Cardio-Thoracic Surgery (Nederlandse Vereniging voor Thoraxchirurgie, NVT) instituted the Adult Cardiac Surgery Database. The dataset comprises demographic factors, type of intervention, in-hospital mortality and 18 risk factors for mortality after cardiac surgery, according to the European System for Cardiac Operative Risk Evaluation definitions. Currently, this procedural database contains over 60 000 interventions. Completeness of data is excellent and national coverage of all 16 Dutch cardio-thoracic surgery centres has been achieved since the start. The primary goal of the database is to control and maintain the quality of care by evaluation of outcomes. This is accomplished by regular feedback and comparison of outcomes. For a subset of the database (procedures from 10 out of 16 centres) longer-term follow-up has been established by means of data linkage to two national registries. This provides information on survival status, causes of death and readmissions. The database has recently been used for research, resulting in methodological papers aimed at optimizing comparison of outcomes. In future, clinical issues will also be addressed, for example survival after coronary artery bypass grafting and valve surgery.

Statistical methods to monitor risk factors in a clinical database: example of a national cardiac surgery registry.

BACKGROUND: Comparison of outcomes requires adequate risk adjustment for differences in patient risk and the type of intervention performed. Both unintentional and intentional misclassification (also called gaming) of risk factors might lead to incorrect benchmark results. Therefore, misclassification of risk factors should be detected. We investigated the use of statistical process control techniques to monitor the frequency of risk factors in a clinical database. METHODS AND RESULTS: A national population-based study was performed using simulation and statistical process control. All patients who underwent cardiac surgery between January 1, 2007, and December 31, 2009, in all 16 cardiothoracic surgery centers in the Netherlands were included. Data on 46 883 consecutive cardiac surgery interventions were extracted. The expected risk factor frequencies were based on 2007 and 2008 data. Monthly frequency rates of 18 risk factors in 2009 were monitored using a Shewhart control chart, exponentially weighted moving average chart, and cumulative sum chart. Upcoding (ie, gaming) in random patients was simulated and detected in 100% of the simulations. Subtle forms of gaming, involving specifically high-risk patients, were more difficult to identify (detection rate of 44%). However, the accompanying rise in mean logistic European system for cardiac operative risk evaluation (EuroSCORE) was detected in all simulations. CONCLUSIONS: Statistical process control in the form of a Shewhart control chart, exponentially weighted moving average, and cumulative sum charts provide a means to monitor changes in risk factor frequencies in a clinical database. Surveillance of the overall expected risk in addition to the separate risk factors ensures a high sensitivity to detect gaming. The use of statistical process control for risk factor surveillance is recommended.

Gaming in risk-adjusted mortality rates: effect of misclassification of risk factors in the benchmarking of cardiac surgery risk-adjusted mortality rates.

OBJECTIVE: Upcoding or undercoding of risk factors could affect the benchmarking of risk-adjusted mortality rates. The aim was to investigate the effect of misclassification of risk factors on the benchmarking of mortality rates after cardiac surgery. METHODS: A prospective cohort was used comprising all adult cardiac surgery patients in all 16 cardiothoracic centers in The Netherlands from January 1, 2007, to December 31, 2009. A random effects model, including the logistic European system for cardiac operative risk evaluation (EuroSCORE) was used to benchmark the in-hospital mortality rates. We simulated upcoding and undercoding of 5 selected variables in the patients from 1 center. These patients were selected randomly (nondifferential misclassification) or by the EuroSCORE (differential misclassification). RESULTS: In the random patients, substantial misclassification was required to affect benchmarking: a 1.8-fold increase in prevalence of the 4 risk factors changed an underperforming center into an average performing one. Upcoding of 1 variable required even more. When patients with the greatest EuroSCORE were upcoded (ie, differential misclassification), a 1.1-fold increase was sufficient: moderate left ventricular function from 14.2% to 15.7%, poor left ventricular function from 8.4% to 9.3%, recent myocardial infarction from 7.9% to 8.6%, and extracardiac arteriopathy from 9.0% to 9.8%. CONCLUSIONS: Benchmarking using risk-adjusted mortality rates can be manipulated by misclassification of the EuroSCORE risk factors. Misclassification of random patients or of single variables will have little effect. However, limited upcoding of multiple risk factors in high-risk patients can greatly influence benchmarking. To minimize "gaming," the prevalence of all risk factors should be carefully monitored.

[Performance indicators for hospitals]. / Prestatie-indicatoren voor ziekenhuizen.

A good performance indicator reflects the quality of care and uses clinical outcomes. When outcomes are difficult to obtain, process and structure variables can provide a good picture of quality of care. A single performance indicator for the entire hospital is unattainable; efforts should focus on performance indicators for specific disorders. There are limitations to the use of performance indicators to compare hospitals; these include correction for case mix, the statistical reliability of the measurements and the validation of performance indicators. Well-considered performance indicators can be used to monitor trends and identify providers that perform below a certain benchmark, but not to rank them.

Limitations of ranking lists based on cardiac surgery mortality rates.

BACKGROUND: Ranking lists are a common way of reporting performance in cardiac surgery; however, rankings have shown to be imprecise, yet the extent of this imprecision is unknown. We aimed to determine the precision of, and fluctuations in, ranking lists in the comparison of cardiac surgery mortality rates. METHODS AND RESULTS: Information on all adult cardiac surgery patients in all 16 cardiothoracic centers in The Netherlands from January 1, 2007, until December 31, 2009, was extracted from the database of the Netherlands Association for Cardio-Thoracic Surgery (n=46883). Ranks were assessed using crude and adjusted mortality rates, using a random effects logistic regression model. Risk adjustment was performed using the logistic EuroSCORE. Statistical precision of ranks was assessed with 95% confidence intervals. Additional analyses were performed for patients with isolated coronary artery bypass grafting. The ranking lists, based on mortality rates in 3 consecutive years, showed considerable reshuffling. When all data were pooled, the mean width of the 95% confidence intervals was 10 ranks using crude and 8 ranks using adjusted mortality rates. The large overlap of the confidence intervals across hospitals indicates that rank statistics were not materially different. Results were similar in the isolated coronary artery bypass grafting subgroup. CONCLUSIONS: Rankings are an imprecise statistical method to report cardiac surgery mortality rates and prone to (random) fluctuation. Hence, reshuffling of ranks can be expected solely due to chance. Therefore, we strongly discourage the use of ranking lists in the comparison of mortality rates.

Performance of the original EuroSCORE.

The European system for cardiac operative risk evaluation (EuroSCORE) is a commonly used risk score for operative mortality following cardiac surgery. We aimed to conduct a systematic review of the performance of the additive and logistic EuroSCORE. A literature search resulted in 67 articles. Studies applying the EuroSCORE on patients undergoing cardiac surgery and which reported early mortality were included. Weighted meta-regression showed that the EuroSCORE overestimated mortality. However, this performance depended on the risk profile of patients: in high-risk patients, the additive model actually underestimated mortality. Discriminative performance was good. Given the poor predictive performance, the EuroSCORE may not be suitable as a tool for patient selection nor for benchmarking.

Carcinoid heart disease: outcomes after surgical valve replacement.

OBJECTIVES: To describe the early and late outcomes of carcinoid patients undergoing surgical heart valve replacement. METHODS: In a retrospective study, records of patients with symptomatic carcinoid heart disease referred for valve surgery between 1993 and 2010 at two academic centres were reviewed. The perioperative and postoperative outcomes were analysed. RESULTS: Nineteen patients, with a mean age of 56 ± 9.6 years, underwent cardiac surgery for carcinoid syndrome. Sixteen patients underwent implantation of one or more mechanical bileaflet valve prosthesis and three patients had one or more bioprosthetic valves implanted. Survival after 1 and 5 years was 71 and 43%, respectively. Six out of nine survivors were at last follow-up in New York Heart Association class I. Valve-related events such as valve thrombosis or bleeding complications were not registered. Echocardiography showed improvement of right ventricular dilatation in 80% of patients. CONCLUSIONS: Despite advanced cardiac morbidity at the time of operation, early postoperative survival was 90%. Long-term survival of patients with carcinoid heart disease undergoing valve replacement is determined by carcinoid progression. The surviving patients had a persistent improvement in functional capacity without valve-related complications of the mechanical prosthesis.

[Risk-adjusted hospital mortality rates]. / Risicogewogen ziekenhuismortaliteit: baas over eigen sterftecijfers.

The publication of inadequately adjusted mortality rates has led to incorrect and unfair comparison of outcomes in quality of care between hospitals. In order to ensure adequate risk-adjustment of such outcomes, care providers should maintain their own registries. Such databases enable the monitoring and benchmarking of outcomes adjusted for case mix. One example is the Netherlands Association for Cardio-Thoracic Surgery database. The dataset consists of 18 risk factors for in-hospital mortality and the outcome in-hospital mortality for adult patients undergoing cardiac surgery in the Netherlands. More than 60,000 interventions have been included since 2007. The goal of the database is to control and to improve the quality of care by providing frequent feedback to the participating hospitals about their risk-adjusted mortality rates. Other care providers should follow this example and register their own risk-adjusted outcomes. Such registries will function as a quality instrument and will provide an in-depth explanation of the oversimplified results that are often published.