Residency · Residency · Cardiothoracic Surgery
Quality Improvement and Outcomes Reporting in CT Surgery
Introduction
Cardiothoracic surgery has been a leader in quality improvement (QI) and outcomes reporting among surgical specialties. The establishment of the Society of Thoracic Surgeons (STS) National Database in 1989 marked a paradigm shift toward transparency, benchmarking, and data-driven performance improvement. QI methodology, risk-adjusted outcomes analysis, and public reporting are now integral to the practice and evolution of CT surgery.
The STS National Database
Structure and Scope
Established in 1989, the STS National Database is currently the largest CT surgery outcomes database globally. It comprises three components: the Adult Cardiac Surgery Database (ACSD), the General Thoracic Surgery Database (GTSD), and the Congenital Heart Surgery Database (CHSD). The database captures data on more than 7 million procedures from over 3,800 participating surgeons and more than 1,100 practice groups. Data elements include patient demographics, comorbidities, operative details, and 30-day outcomes.
Risk Adjustment Models
The STS Predicted Risk of Mortality (PROM) estimates expected mortality based on patient risk factors, allowing comparison of observed versus expected outcomes. Models are updated regularly using contemporary data to maintain accuracy. Separate models exist for CABG, valve surgery, CABG plus valve, and general thoracic procedures. Risk adjustment enables fair comparison across programs with different patient populations. The observed-to-expected (O/E) ratio serves as a key metric: a ratio below 1.0 indicates better-than-expected performance, while a ratio above 1.0 indicates worse-than-expected.
STS Star Rating System
The star rating system is a composite quality measure incorporating mortality, major morbidity, and process measures. Programs are rated with 1 star (lowest), 2 stars, or 3 stars (highest performance). These ratings have been publicly available on the STS website since 2010 for isolated CABG, driving transparency and incentivizing quality improvement.
Quality Metrics in CT Surgery
Process Measures
Key process measures include preoperative beta-blocker administration before CABG, internal mammary artery use for CABG (with a target exceeding 95% for elective isolated CABG), appropriate antibiotic prophylaxis timing within 60 minutes of incision, perioperative glycemic control with blood glucose below 180 mg/dL, and appropriate discharge medications including aspirin, beta-blocker, statin, and ACE inhibitor.
Outcome Measures
| Metric Type | Measure | Definition/Target |
|---|---|---|
| Process | IMA use for CABG | Target >95% for elective isolated CABG |
| Process | Antibiotic prophylaxis timing | Within 60 minutes of incision |
| Process | Perioperative glucose control | Blood glucose <180 mg/dL |
| Process | Discharge medications | Aspirin, beta-blocker, statin, ACE inhibitor |
| Outcome | Operative mortality | Death within 30 days or index hospitalization |
| Outcome | Major morbidity | Stroke, renal failure, prolonged vent >24h, DSWI, reoperation |
| Outcome | STS composite score | Combined mortality + morbidity endpoint |
| Outcome | 30-day readmission | Unplanned readmission within 30 days |
| Balancing | Risk aversion | Monitoring case mix to detect inappropriate patient selection |
| Balancing | Failure-to-rescue | Mortality after a complication has occurred |
Operative mortality is defined as death within 30 days or during the index hospitalization. Major morbidity encompasses stroke, renal failure, prolonged ventilation beyond 24 hours, deep sternal wound infection, and reoperation for bleeding. The STS composite score combines mortality and morbidity into a single endpoint. Readmission rates track 30-day unplanned readmissions. Patient-reported outcomes including functional status, quality of life, and symptom burden are increasingly incorporated.
Balancing Measures
Risk aversion is a critical concern, as public reporting may lead surgeons to avoid high-risk patients who may benefit from surgery. Monitoring case mix detects inappropriate risk selection. Evaluating failure-to-rescue rates captures the ability to recognize and manage complications, which is as important as preventing them.
Quality Improvement Methodologies
Plan-Do-Study-Act (PDSA) Cycle
The PDSA cycle begins with identifying the problem, analyzing root causes, and developing an intervention (Plan). The intervention is then implemented on a small scale as a pilot (Do). Data are collected and the effect of the intervention is evaluated (Study). Based on results, the intervention is adopted, modified, or abandoned, and the cycle repeats (Act). This iterative process drives continuous improvement.
Lean and Six Sigma
Lean methodology focuses on eliminating waste such as unnecessary steps, delays, and defects in processes, using value stream mapping to identify bottlenecks. Six Sigma is a data-driven approach to reducing variation and defects, employing the DMAIC framework (Define, Measure, Analyze, Improve, Control). Lean Six Sigma combines both approaches and is widely applied in OR efficiency, ICU throughput, and infection reduction programs.
Root Cause Analysis (RCA)
Root cause analysis is a structured investigation following adverse events or near-misses that identifies system-level failures rather than assigning individual blame. Tools include the fishbone (Ishikawa) diagram and the 5 Whys technique. RCA generates actionable corrective measures to prevent recurrence.
Morbidity and Mortality (M&M) Conference
The M&M conference is a traditional and essential QI activity in surgical training and practice, serving as a non-punitive, educational forum for reviewing adverse outcomes and complications. The focus is on system failures, decision-making processes, and cognitive errors. These conferences are protected by peer-review statutes in most jurisdictions.
Public Reporting and Transparency
Benefits of Public Reporting
Public reporting promotes accountability and drives quality improvement. It empowers patients to make informed decisions about where to receive care, enables identification of outlier programs for intervention and support, and provides data for payers, regulators, and accreditation organizations.
Concerns and Challenges
Risk aversion is a significant concern, as surgeons may decline to operate on the highest-risk patients to protect outcomes metrics. Gaming through potential upcoding of comorbidities to inflate expected risk is another challenge. Data accuracy may suffer because voluntary reporting can result in incomplete or inaccurate data entry. Statistical noise affects low-volume programs, which may have unstable metrics due to small sample sizes. Mortality alone is an incomplete quality measure, and composite scores and process measures provide a more comprehensive picture.
Models of Public Reporting
The STS star ratings offer voluntary, risk-adjusted composite quality scores. The New York State Cardiac Surgery Reporting System has provided mandatory, publicly reported surgeon-level mortality data since 1989 and, though controversial, has been associated with improved outcomes. The Centers for Medicare and Medicaid Services (CMS) Hospital Compare website includes cardiac surgery outcomes. Consumer Reports and US News rankings use publicly available data for hospital rankings.
Institutional Quality Programs
Enhanced Recovery After Surgery (ERAS) in CT Surgery
ERAS protocols are multimodal, evidence-based approaches to optimizing perioperative care. Components include preoperative optimization, multimodal analgesia, early extubation, early mobilization, and goal-directed fluid therapy. These protocols have demonstrated reductions in length of stay, complications, and costs.
Surgical Safety Checklists
Surgical safety checklists are based on the WHO Surgical Safety Checklist and adapted for CT surgery, incorporating pre-bypass, pre-separation, and post-bypass verification steps. They reduce communication failures and preventable errors.
Team-Based Training
Crew Resource Management (CRM) applies aviation-derived principles to the OR team, emphasizing communication, situational awareness, and speaking up about safety concerns. Structured handoff protocols such as I-PASS standardize ICU transfer from the OR.
Key Clinical Pearls
The STS National Database has been transformative in establishing CT surgery as a leader in quality measurement and improvement, and participation with accurate data entry is a professional obligation. Risk adjustment is essential for fair comparison of outcomes across programs, as unadjusted mortality rates are misleading. Public reporting has improved outcomes overall, but the risk of unintended consequences such as patient risk aversion must be actively monitored. QI is a continuous process rather than a one-time project, and the PDSA cycle embodies this philosophy of iterative improvement. Failure-to-rescue is an increasingly important metric that captures the ability to recognize and manage complications, distinct from complication prevention alone.
References
- Shahian DM, Jacobs JP, Badhwar V, et al. The Society of Thoracic Surgeons 2018 adult cardiac surgery risk models. Annals of Thoracic Surgery. 2018;105(5):1411-1418.
- Jacobs JP, Shahian DM, D'Agostino RS, et al. The Society of Thoracic Surgeons National Database 2023 update on outcomes and quality. Annals of Thoracic Surgery. 2023;115(3):545-574.
- Hannan EL, Cozzens K, King SB, et al. The New York State cardiac surgery reporting system: 25 years later. Annals of Thoracic Surgery. 2012;93(6):1657-1663.
- Grant SW, Hickey GL, Dimarakis I, et al. How does EuroSCORE II perform in UK cardiac surgery: an analysis of 23,740 patients from the STS UK database. BMJ Open. 2012;2(6):e001813.