Development of a clinical registry-based 30-day readmission measure for coronary artery bypass grafting surgery.

BACKGROUND: Reducing readmissions is a major healthcare reform goal, and reimbursement penalties are imposed for higher-than-expected readmission rates. Most readmission risk models and performance measures are based on administrative rather than clinical data. METHODS AND RESULTS: We examined rates and predictors of 30-day all-cause readmission following coronary artery bypass grafting surgery by using nationally representative clinical data (2008-2010) from the Society of Thoracic Surgeons National Database linked to Medicare claims records. Among 265 434 eligible Medicare records, 226 960 (86%) were successfully linked to Society of Thoracic Surgeons records; 162 572 (61%) isolated coronary artery bypass grafting admissions constituted the study cohort. Logistic regression was used to identify readmission risk factors; hierarchical regression models were then estimated. Risk-standardized readmission rates ranged from 12.6% to 23.6% (median, 16.8%) among 846 US hospitals with ≥30 eligible cases and ≥90% of eligible Centers for Medicare and Medicaid Services records linked to the Society of Thoracic Surgeons database. Readmission predictors (odds ratios [95% confidence interval]) included dialysis (2.02 [1.87-2.19]), severe chronic lung disease (1.58 [1.49-1.68]), creatinine (2.5 versus 1.0 or lower:1.49 [1.41-1.57]; 2.0 versus 1.0 or lower: 1.37 [1.32-1.43]), insulin-dependent diabetes mellitus (1.45 [1.39-1.51]), obesity in women (body surface area 2.2 versus 1.8: 1.44 [1.35-1.53]), female sex (1.38 [1.33-1.43]), immunosuppression (1.38 [1.28-1.49]), preoperative atrial fibrillation (1.36 [1.30-1.42]), age per 10-year increase (1.36 [1.33-1.39]), recent myocardial infarction (1.24 [1.08-1.42]), and low body surface area in men (1.22 [1.14-1.30]). C-statistic was 0.648. Fifty-two hospitals (6.1%) had readmission rates statistically better or worse than expected. CONCLUSIONS: A coronary artery bypass grafting surgery readmission measure suitable for public reporting was developed by using the national Society of Thoracic Surgeons clinical data linked to Medicare readmission claims.

Comparative effectiveness of revascularization strategies.

BACKGROUND: Questions persist concerning the comparative effectiveness of percutaneous coronary intervention (PCI) and coronary-artery bypass grafting (CABG). The American College of Cardiology Foundation (ACCF) and the Society of Thoracic Surgeons (STS) collaborated to compare the rates of long-term survival after PCI and CABG. METHODS: We linked the ACCF National Cardiovascular Data Registry and the STS Adult Cardiac Surgery Database to claims data from the Centers for Medicare and Medicaid Services for the years 2004 through 2008. Outcomes were compared with the use of propensity scores and inverse-probability-weighting adjustment to reduce treatment-selection bias. RESULTS: Among patients 65 years of age or older who had two-vessel or three-vessel coronary artery disease without acute myocardial infarction, 86,244 underwent CABG and 103,549 underwent PCI. The median follow-up period was 2.67 years. At 1 year, there was no significant difference in adjusted mortality between the groups (6.24% in the CABG group as compared with 6.55% in the PCI group; risk ratio, 0.95; 95% confidence interval [CI], 0.90 to 1.00). At 4 years, there was lower mortality with CABG than with PCI (16.4% vs. 20.8%; risk ratio, 0.79; 95% CI, 0.76 to 0.82). Similar results were noted in multiple subgroups and with the use of several different analytic methods. Residual confounding was assessed by means of a sensitivity analysis. CONCLUSIONS: In this observational study, we found that, among older patients with multivessel coronary disease that did not require emergency treatment, there was a long-term survival advantage among patients who underwent CABG as compared with patients who underwent PCI. (Funded by the National Heart, Lung, and Blood Institute.).

Predictors of long-term survival after coronary artery bypass grafting surgery: results from the Society of Thoracic Surgeons Adult Cardiac Surgery Database (the ASCERT study).

BACKGROUND: Most survival prediction models for coronary artery bypass grafting surgery are limited to in-hospital or 30-day end points. We estimate a long-term survival model using data from the Society of Thoracic Surgeons Adult Cardiac Surgery Database and Centers for Medicare and Medicaid Services. METHODS AND RESULTS: The final study cohort included 348 341 isolated coronary artery bypass grafting patients aged ≥65 years, discharged between January 1, 2002, and December 31, 2007, from 917 Society of Thoracic Surgeons-participating hospitals, randomly divided into training (n=174 506) and validation (n=173 835) samples. Through linkage with Centers for Medicare and Medicaid Services claims data, we ascertained vital status from date of surgery through December 31, 2008 (1- to 6-year follow-up). Because the proportional hazards assumption was violated, we fit 4 Cox regression models conditional on being alive at the beginning of the following intervals: 0 to 30 days, 31 to 180 days, 181 days to 2 years, and >2 years. Kaplan-Meier-estimated mortality was 3.2% at 30 days, 6.4% at 180 days, 8.1% at 1 year, and 23.3% at 3 years of follow-up. Harrell's C statistic for predicting overall survival time was 0.732. Some risk factors (eg, emergency status, shock, reoperation) were strong predictors of short-term outcome but, for early survivors, became nonsignificant within 2 years. The adverse impact of some other risk factors (eg, dialysis-dependent renal failure, insulin-dependent diabetes mellitus) continued to increase. CONCLUSIONS: Using clinical registry data and longitudinal claims data, we developed a long-term survival prediction model for isolated coronary artery bypass grafting. This provides valuable information for shared decision making, comparative effectiveness research, quality improvement, and provider profiling.

The association of transcatheter aortic valve replacement availability and hospital aortic valve replacement volume and mortality in the United States.

BACKGROUND: Whether the introduction of transcatheter aortic valve replacement (TAVR) has affected hospitals' surgical aortic valve replacement (SAVR) and overall aortic valve replacement (AVR) case volumes and outcomes in the United States is unknown. METHODS: We utilized data from The Society of Thoracic Surgeons (STS) adult cardiac surgery database and the STS/American College of Cardiology (ACC) transcatheter valve therapies registry to examine SAVR and TAVR procedures. Temporal trends in total case volume (SAVR plus TAVR), and observed and risk-adjusted in-hospital mortality rates were assessed among low-risk cases (STS predicted risk of operative mortality < 4%), intermediate-risk cases (4% to 8%), and high-risk cases (> 8%). A contemporary control was provided by non-TAVR centers. RESULTS: From 2008 to 2013, the total annual volume of AVR among 246 TAVR-performing hospitals increased from 19,578 to 33,004, with a 22% growth in SAVR volumes; non-TAVR hospital (n = 555) increases were more modest (16,563 to 19,134; 16% growth). Expanded volumes at TAVR hospitals included increased SAVR use in low- and intermediate-risk cases, and TAVR use in high-risk cases. In parallel, in-hospital mortality for all AVR procedures at TAVR sites declined from 3.4% to 2.9% (observed to expected [O:E] ratio 0.75 to 0.58, p < 0.001); the greatest declines were among intermediate- and high-risk SAVR patients. Owing to reduced SAVR mortality, TAVR centers experienced a significantly greater decline in O:E ratio for high-risk patient in-hospital mortality than non-TAVR centers (TAVR center O:E ratio, 0.81 to 0.61; non-TAVR center O:E ratio, 0.85 to 0.76; p < 0.001). After approval of TAVR for clinical use, a trend toward higher in-hospital mortality rates and O:E ratios for TAVR procedures was observed at new (but not at established) TAVR centers (O:E ratio, 0.41 to 0.67; p = 0.08). CONCLUSIONS: Since the introduction of TAVR, the total volume of AVR procedures, including higher overall use of SAVR, at TAVR sites has significantly increased in the United States. Overall, in-hospital survival of patients undergoing treatment for aortic valve stenosis continues to improve.

Issues in quality measurement: target population, risk adjustment, and ratings.

This review investigates three fundamental issues in health care performance measurement: selection of a homogeneous target population, risk adjustment, and assignment of quality rating categories. Many but not all organizations involved in quality measurement have adopted similar approaches to these important methodological issues. To illustrate the practical implications of different profiling strategies, we use The Society of Thoracic Surgeons' data to compare profiling results derived using prevailing analytical methodologies with those obtained from alternative approaches, exemplified by those of a well-known health care performance rating organization. We demonstrate the differences in provider classification that may result from these methodologic decisions.

The STS-ACC transcatheter valve therapy national registry: a new partnership and infrastructure for the introduction and surveillance of medical devices and therapies.

The Society of Thoracic Surgeons (STS) and American College of Cardiology (ACC) transcatheter valve therapy (TVT) registry is a novel, national registry for all new TVT devices created through a partnership of the STS and the ACC in close collaboration with the Food and Drug Administration, the Center for Medicare and Medicaid Services, and the Duke Clinical Research Institute. The registry will serve as an objective, comprehensive, and scientifically based resource to improve the quality of patient care, to monitor the safety and effectiveness of TVT devices, to serve as an analytic resource for TVT research, and to enhance communication among key stakeholders.

Successful linking of the Society of Thoracic Surgeons Database to Social Security data to examine the accuracy of Society of Thoracic Surgeons mortality data.

OBJECTIVES: The Society of Thoracic Surgeons Adult Cardiac Surgery Database has been linked to the Social Security Death Master File to verify "life status" and evaluate long-term surgical outcomes. The objective of this study is explore practical applications of the linkage of the Society of Thoracic Surgeons Adult Cardiac Surgery Database to Social Securtiy Death Master File, including the use of the Social Securtiy Death Master File to examine the accuracy of the Society of Thoracic Surgeons 30-day mortality data. METHODS: On January 1, 2008, the Society of Thoracic Surgeons Adult Cardiac Surgery Database began collecting Social Security numbers in its new version 2.61. This study includes all Society of Thoracic Surgeons Adult Cardiac Surgery Database records for operations with nonmissing Social Security numbers between January 1, 2008, and December 31, 2010, inclusive. To match records between the Society of Thoracic Surgeons Adult Cardiac Surgery Database and the Social Security Death Master File, we used a combined probabilistic and deterministic matching rule with reported high sensitivity and nearly perfect specificity. RESULTS: Between January 1, 2008, and December 31, 2010, the Society of Thoracic Surgeons Adult Cardiac Surgery Database collected data for 870,406 operations. Social Security numbers were available for 541,953 operations and unavailable for 328,453 operations. According to the Society of Thoracic Surgeons Adult Cardiac Surgery Database, the 30-day mortality rate was 17,757/541,953 = 3.3%. Linkage to the Social Security Death Master File identified 16,565 cases of suspected 30-day deaths (3.1%). Of these, 14,983 were recorded as 30-day deaths in the Society of Thoracic Surgeons database (relative sensitivity = 90.4%). Relative sensitivity was 98.8% (12,863/13,014) for suspected 30-day deaths occurring before discharge and 59.7% (2120/3551) for suspected 30-day deaths occurring after discharge. CONCLUSIONS: Linkage to the Social Security Death Master File confirms the accuracy of data describing "mortality within 30 days of surgery" in the Society of Thoracic Surgeons Adult Cardiac Surgery Database. The Society of Thoracic Surgeons and Social Security Death Master File link reveals that capture of 30-day deaths occurring before discharge is highly accurate, and that these in-hospital deaths represent the majority (79% [13,014/16,565]) of all 30-day deaths. Capture of the remaining 30-day deaths occurring after discharge is less complete and needs improvement. Efforts continue to encourage Society of Thoracic Surgeons Database participants to submit Social Security numbers to the Database, thereby enhancing accurate determination of 30-day life status. The Society of Thoracic Surgeons and Social Security Death Master File linkage can facilitate ongoing refinement of mortality reporting.

The Society of Thoracic Surgeons Isolated Aortic Valve Replacement (AVR) Composite Score: a report of the STS Quality Measurement Task Force.

BACKGROUND: Risk-standardized mortality rates provide a valuable but incomplete assessment of provider performance. Consequently, The Society of Thoracic Surgeons (STS) previously developed a multidimensional composite quality measure for coronary artery bypass grafting, the most frequently performed cardiac surgical procedure. The current study creates a similar composite measure for isolated aortic valve replacement (AVR). METHODS: Because there are few widely accepted process measures for AVR, the STS AVR composite score is based solely on outcomes, including risk-standardized mortality and any-or-none risk-standardized morbidity (occurrence of sternal infection, reoperation, stroke, renal failure, or prolonged ventilation). Isolated AVR is performed less frequently than coronary artery bypass grafting, and 1 year of data provided inadequate sample sizes for profiling. Therefore, we investigated observation periods of 3 years (July 1, 2007, to June 30, 2010: 67,138 records, 2,082 deaths, and 11,962 morbidity events) and 5 years (July 1, 2005, to June 30, 2010: 101,269 records, 3,123 deaths, and 17,514 morbidity events). We also compared results using 90%, 95%, and 98% credible intervals, corresponding to 95%, 97.5%, and 99% Bayesian probabilities, to determine "star ratings." RESULTS: Differences between 3-year and 5-year results were small; the former was chosen because this time frame provides more current and relevant data. Using 3 years of data and 95% credible intervals, adjusted mortality and morbidity rates varied threefold from highest performing (3 stars) to lowest performing (1 star) programs. Approximately 3% of participants were 1-star, 6% were 3-star, and 91% were 2-star programs. CONCLUSIONS: STS has developed a composite mortality and morbidity outcomes measure for isolated AVR to be used in quality assessment, provider feedback, public reporting, and performance improvement.

Public reporting of cardiac surgery performance: Part 2--implementation.

Appropriate implementation is essential to create a credible public reporting system. Ideally, data should be obtained from an audited clinical data registry, and structure, process, or outcomes metrics may be reported. Composite measures are increasingly used, as are measures of appropriateness, patient satisfaction, functional status, and health-related quality of life. Classification of provider performance should use statistical criteria appropriate to the policy objectives and to the desired balance of sensitivity and specificity. Public reports should use simplified visual or tabular presentation aids that maximize correct interpretation of numerical data. Because of sample size issues, and to emphasize that cardiac surgery requires team-based care, public reporting should generally be focused at the program rather than individual surgeon level. This may also help to mitigate risk aversion, the avoidance of high-risk patients.

Public reporting of cardiac surgery performance: Part 1--history, rationale, consequences.

Cardiac surgical report cards have historically been mandatory. This paradigm changed when The Society of Thoracic Surgeons recently implemented a voluntary public reporting program based on benchmark analyses from its National Cardiac Database. The primary rationale is to provide transparency and accountability, thus affirming the fundamental ethical right of patient autonomy. Previous studies suggest that public reporting facilitates quality improvement, although other approaches such as confidential feedback of results and regional quality improvement initiatives are also effective. Public reporting has not substantially impacted patient referral patterns or market share. However, this may change with implementation of healthcare reform and with refinement of public reporting formats to enhance consumer interpretability. Finally, the potential unintended adverse consequences of public reporting must be monitored, particularly to assure that hospitals and surgeons remain willing to care for high-risk patients.

Successful linking of the Society of Thoracic Surgeons database to social security data to examine survival after cardiac operations.

BACKGROUND: Long-term evaluation of cardiothoracic surgical outcomes is a major goal of The Society of Thoracic Surgeons (STS). Linking the STS Database to the Social Security Death Master File (SSDMF) allows for the verification of "life status." This study demonstrates the feasibility of linking the STS Database to the SSDMF and examines longitudinal survival after cardiac operations. METHODS: For all operations in the STS Adult Cardiac Surgery Database performed in 2008 in patients with an available Social Security Number, the SSDMF was searched for a matching Social Security Number. Survival probabilities at 30 days and 1 year were estimated for nine common operations. RESULTS: A Social Security Number was available for 101,188 patients undergoing isolated coronary artery bypass grafting, 12,336 patients undergoing isolated aortic valve replacement, and 6,085 patients undergoing isolated mitral valve operations. One-year survival for isolated coronary artery bypass grafting was 88.9% (6,529 of 7,344) with all vein grafts, 95.2% (84,696 of 88,966) with a single mammary artery graft, 97.4% (4,422 of 4,540) with bilateral mammary artery grafts, and 95.6% (7,543 of 7,890) with all arterial grafts. One-year survival was 92.4% (11,398 of 12,336) for isolated aortic valve replacement (95.6% [2,109 of 2,206] with mechanical prosthesis and 91.7% [9,289 of 10,130] with biologic prosthesis), 86.5% (2,312 of 2,674) for isolated mitral valve replacement (91.7% [923 of 1,006] with mechanical prosthesis and 83.3% [1,389 of 1,668] with biologic prosthesis), and 96.0% (3,275 of 3,411) for isolated mitral valve repair. CONCLUSIONS: Successful linkage to the SSDMF has substantially increased the power of the STS Database. These longitudinal survival data from this large multi-institutional study provide reassurance about the durability and long-term benefits of cardiac operations and constitute a contemporary benchmark for survival after cardiac operations.

The Society of Thoracic Surgeons 2008 cardiac surgery risk models: part 1--coronary artery bypass grafting surgery.

BACKGROUND: The first version of The Society of Thoracic Surgeons National Adult Cardiac Surgery Database (STS NCD) was developed nearly 2 decades ago. Since its inception, the number of participants has grown dramatically, patient acuity has increased, and overall outcomes have consistently improved. To adjust for these and other changes, all STS risk models have undergone periodic revisions. This report provides a detailed description of the 2008 STS risk model for coronary artery bypass grafting surgery (CABG). METHODS: The study population consisted of 774,881 isolated CABG procedures performed on adult patients aged 20 to 100 years between January 1, 2002, and December 31, 2006, at 819 STS NCD participating centers. This cohort was randomly divided into a 60% training (development) sample and a 40% test (validation) sample. The development sample was used to identify predictor variables and estimate model coefficients. The validation sample was used to assess model calibration and discrimination. Model outcomes included operative mortality, renal failure, stroke, reoperation for any cause, prolonged ventilation, deep sternal wound infection, composite major morbidity or mortality, prolonged length of stay (> 14 days), and short length of stay (< 6 days and alive). Candidate predictor variables were selected based on their availability in versions 2.35, 2.41, and 2.52.1 of the STS NCD and their presence in (or ability to be mapped to) version 2.61. Potential predictor variables were screened for overall prevalence in the study population, missing data frequency, coding concerns, bivariate relationships with outcomes, and their presence in previous STS or other CABG risk models. Supervised backwards selection was then performed with input from an expert panel of cardiac surgeons and biostatisticians. After successfully validating the fit of the models, the development and validation samples were subsequently combined, and the final regression coefficients were estimated using the overall combined (development plus validation) sample. RESULTS: The c-index for the mortality model was 0.812, and the c-indices for other endpoints ranged from 0.653 for reoperation to 0.793 for renal failure in the validation sample. Plots of observed versus predicted event rates revealed acceptable calibration in the overall population and in numerous subgroups. When patients were grouped into categories of predicted risk, the absolute difference between the observed and expected event rates was less than 1.5% for each endpoint. The final model intercept and coefficients are provided. CONCLUSIONS: New STS risk models have been developed for CABG mortality and eight other endpoints. Detailed descriptions of model development and testing are provided, together with the final algorithm. Overall model performance is excellent.

The Society of Thoracic Surgeons 2008 cardiac surgery risk models: part 2--isolated valve surgery.

BACKGROUND: Adjustment for case-mix is essential when using observational data to compare surgical techniques or providers. That is most often accomplished through the use of risk models that account for preoperative patient factors that may impact outcomes. The Society of Thoracic Surgeons (STS) uses such risk models to create risk-adjusted performance reports for participants in the STS National Adult Cardiac Surgery Database (NCD). Although risk models were initially developed for coronary artery bypass surgery, similar models have now been developed for use with heart valve surgery, particularly as the proportion of such procedures has increased. The last published STS model for isolated valve surgery was based on data from 1994 to 1997 and did not include patients undergoing mitral valve repair. STS has developed new valve surgery models using contemporary data that include both valve repair as well as replacement. Expanding upon existing valve models, the new STS models include several nonfatal complications in addition to mortality. METHODS: Using STS data from 2002 to 2006, isolated valve surgery risk models were developed for operative mortality, permanent stroke, renal failure, prolonged ventilation (> 24 hours), deep sternal wound infection, reoperation for any reason, a major morbidity or mortality composite endpoint, prolonged postoperative length of stay, and short postoperative length of stay. The study population consisted of adult patients who underwent one of three types of valve surgery: isolated aortic valve replacement (n = 67,292), isolated mitral valve replacement (n = 21,229), or isolated mitral valve repair (n = 21,238). The population was divided into a 60% development sample and a 40% validation sample. After an initial empirical investigation, the three surgery groups were combined into a single logistic regression model with numerous interactions to allow the covariate effects to differ across these groups. Variables were selected based on a combination of automated stepwise selection and expert panel review. RESULTS: Unadjusted operative mortality (in-hospital regardless of timing, and 30-day regardless of venue) for all isolated valve procedures was 3.4%, and unadjusted in-hospital morbidity rates ranged from 0.3% for deep sternal wound infection to 11.8% for prolonged ventilation. The number of predictors in each model ranged from 10 covariates in the sternal infection model to 24 covariates in the composite mortality plus morbidity model. Discrimination as measured by the c-index ranged from 0.639 for reoperation to 0.799 for mortality. When patients in the validation sample were grouped into 10 categories based on deciles of predicted risk, the average absolute difference between observed versus predicted events within these groups ranged from 0.06% for deep sternal wound infection to 1.06% for prolonged postoperative stay. CONCLUSIONS: The new STS risk models for valve surgery include mitral valve repair as well as multiple endpoints other than mortality. Model coefficients are provided and an online risk calculator is publicly available from The Society of Thoracic Surgeons website.

The Society of Thoracic Surgeons 2008 cardiac surgery risk models: part 3--valve plus coronary artery bypass grafting surgery.

BACKGROUND: Since 1999, The Society of Thoracic Surgeons (STS) has published two risk models that can be used to adjust the results of valve surgery combined with coronary artery bypass graft surgery (CABG). The most recent was developed from data for patients who had surgery between 1994 and 1997 using operative mortality as the only endpoint. Furthermore, this model did not specifically consider mitral valve repair plus CABG, an increasingly common procedure. Consistent with STS policy of periodically updating and improving its risk models, new models for valve surgery combined with CABG have been developed. These models specifically address both perioperative morbidity and mitral valve repair, and they are based on contemporary data. METHODS: The final study population consisted of 101,661 procedures, including aortic valve replacement (AVR) plus CABG, mitral valve replacement (MVR) plus CABG, or mitral valve repair (MVRepair) plus CABG between January 1, 2002, and December 31, 2006. Model outcomes included operative mortality, stroke, deep sternal wound infection, reoperation, prolonged ventilation, renal failure, composite major morbidity or mortality, prolonged postoperative length of stay, and short postoperative length of stay. Candidate variables were screened for frequency of missing data, and imputation techniques were used where appropriate. Stepwise variable selection was employed, supplemented by advice from an expert panel of cardiac surgeons and biostatisticians. Several variables were forced into models to insure face validity (eg, atrial fibrillation for the permanent stroke model, sex for all models). Based on preliminary analyses of the data, a single model was employed for valve plus CABG, with indicator variables for the specific type of procedure. Interaction terms were included to allow for differential impact of predictor variables depending on procedure type. After validating the model in the 40% validation sample, the development and validation samples were then combined, and the final model coefficients were estimated using the overall 100% combined sample. The final logistic regression model was estimated using generalized estimating equations to account for clustering of patients within institutions. RESULTS: The c-index for mortality prediction for the overall valve plus CABG population was 0.75. Morbidity model c-indices for specific complications (permanent stroke, renal failure, prolonged ventilation > 24 hours, deep sternal wound infection, reoperation for any reason, major morbidity or mortality composite, and prolonged postoperative length of stay) for the overall group of valve plus CABG procedures ranged from 0.622 to 0.724, and calibration was excellent. CONCLUSIONS: New STS risk models have been developed for heart valve surgery combined with CABG. These are the first valve plus CABG models that also include risk prediction for individual major morbidities, composite major morbidity or mortality, and short and prolonged length of stay.