STS Risk Models Overview
The Society of Thoracic Surgeons (STS) Risk Models represent the gold standard for predicting morbidity and mortality in adult cardiac surgery. Continuously refined using the STS National Database—which captures data from nearly all adult cardiac surgeries in the United States—these models provide unparalleled, benchmarked risk estimates.
Why Risk Assessment is Mandatory
Cardiac surgery represents a major physiological stress test. Objective risk assessment is required to:
- Guide informed consent, ensuring the patient understands their specific numerical risk of death or major complications.
- Facilitate Heart Team discussions when comparing surgery to less invasive options (e.g., SAVR vs. TAVR).
- Allow hospitals to track quality metrics and participate in national public reporting.
Core Variables in Risk Prediction
The STS models utilize highly granular data, including:
- Demographics & Anthropometrics: Age, gender, height, and weight.
- Cardiovascular Status: Previous MIs, heart failure symptoms (NYHA class), left ventricular ejection fraction (LVEF), and coronary anatomy.
- Systemic Disease: Renal failure, dialysis, chronic lung disease, diabetes, and peripheral arterial disease.
- Procedural Specifics: Urgency (elective vs. emergent), reoperation status, and the exact type of procedure planned.
Risk Percentage = Probability output derived from STS database logistic regression models