Age (years) Enter age in whole years (18 to 120)

Sex (categorical) Select sex Male Female Select biological sex as recorded in medical records

Body Surface Area (m²) Enter BSA in square meters (e.g., 1.85)

Ejection Fraction (%) Enter ejection fraction as a percentage (e.g., 55.0)

Serum Creatinine (mg/dL) Enter serum creatinine in mg/dL (e.g., 1.2)

Diabetes (categorical) Select status No Yes Select whether diabetes is present

Hypertension (categorical) Select status No Yes Select whether high blood pressure is present

Chronic Lung Disease (categorical) Select status No Yes Select whether chronic lung disease is present

Renal Failure / Dialysis (categorical) Select status No Yes Select whether renal failure or dialysis is present

Prior Cardiac Surgery (categorical) Select status No Yes Select whether prior heart surgery has been performed

Procedure Type (categorical) Select procedure Isolated CABG Isolated AVR CABG + AVR Mitral Valve Repair Mitral Valve Replacement Select the planned cardiac surgery type

Quick Examples:

Low-Risk Elective CABG High-Risk Elderly Patient

Calculate Clear

This calculator provides an approximate estimate based on a simplified model and is not the official STS Risk Calculator. It should not be used for clinical decision-making. For personalized risk assessment, consult a qualified healthcare professional or use the official STS tool.

What Is Predicted Risk of Mortality

Predicted Risk of Mortality, or PROM, is a number that shows the chance of death during or soon after heart surgery. It is based on factors like age, heart function, and other health problems. PROM does not tell you exactly what will happen. Instead, it gives an estimate built from data on many past patients who had similar surgeries. Doctors use PROM to talk with patients about what to expect.

How Predicted Risk of Mortality Is Calculated

Formula

The formula uses a method called logistic regression. First, it takes each risk factor and multiplies it by a number called a coefficient. These coefficients come from studying thousands of real surgery patients. Then it adds all those products together with a starting number called the intercept. The intercept changes based on the type of surgery. Finally, the formula converts that total into a percentage chance using a math curve that keeps the answer between 0 and 100 percent.

Why Predicted Risk of Mortality Matters

Knowing your estimated surgical risk helps you and your care team make informed choices. It turns complex health data into a single number that is easier to talk about and compare. This number may guide decisions about timing, type of procedure, or extra steps to lower risk.

Why Understanding Surgical Risk Is Important for Informed Decision-Making

When patients and doctors do not discuss surgical risk, they may miss important information. A patient might choose surgery without knowing the full picture, or avoid a needed procedure based on fear rather than facts. Understanding the estimated risk helps balance the benefits of surgery against its possible downsides. This shared knowledge supports better conversations and choices.

For Surgical Planning

Surgeons may use the estimated risk to decide between different procedures or approaches. For example, a less invasive method might be considered if the estimated risk with open surgery is higher. The number helps the surgical team plan for extra monitoring, special equipment, or added support after surgery.

For Patient Counseling and Shared Decision-Making

Patients often want to know what their chances are before agreeing to surgery. The estimated risk gives a starting point for that talk. It helps patients ask better questions and feel more involved in their care. A clear number may reduce anxiety by replacing unknown fears with a concrete estimate.

For Older Adults

Age is one of the strongest factors in this model. Older patients often have more health conditions that add to their risk score. For adults over 75, even a normal ejection fraction or kidney function may not offset the effect of age alone. Older patients and their families may consider discussing whether the benefits of surgery outweigh the estimated risk in their specific case.

STS Risk Calculator vs EuroSCORE

The STS model and EuroSCORE are two different tools that estimate cardiac surgery risk. STS is built from data mostly in North America and is often used for CABG and valve surgery. EuroSCORE was developed in Europe and covers a broader range of heart operations. They use different factors and can give different numbers for the same patient. Neither replaces the other, and doctors may look at both when making decisions.

Example Calculation

Consider a 55-year-old male patient scheduled for isolated CABG. His body surface area is 1.9 m², his ejection fraction is 60%, and his serum creatinine is 1.0 mg/dL. He has no diabetes, no hypertension, no chronic lung disease, no renal failure, and no prior cardiac surgery.

Each factor contributes differently to the overall risk based on its relative importance. These contributions are combined to produce a final estimated probability.

Predicted Risk of Mortality: 1.50%. Composite Morbidity/Mortality Risk: 3.64%. Risk Category: Standard risk range.

This result suggests the patient falls within a range that is generally associated with favorable outcomes for this procedure. However, individual results may vary based on factors not captured by the model. The patient and doctor may use this estimate as one part of a broader discussion about the planned surgery.

Frequently Asked Questions

Who is this STS Risk Calculator for?

This calculator is designed for adults aged 18 and older who are being considered for common cardiac surgeries such as CABG, aortic valve replacement, or mitral valve surgery. It is most useful for patients and clinicians who want a general estimate of operative risk before making treatment decisions.

How often should STS risk be calculated before surgery?

Risk is typically calculated once during the surgical planning phase, often at the visit when the decision for surgery is made. If a patient's health changes significantly before the operation date, the calculation may be repeated with updated lab values or new conditions.

Does the STS risk score apply to all types of heart surgery?

This simplified model covers isolated CABG, isolated aortic valve replacement, combined CABG with AVR, mitral valve repair, and mitral valve replacement. It may not be as reliable for less common procedures like aortic root replacement, transplant, or congenital heart repairs.

Can I use this calculator if I have a complex medical condition?

This calculator uses a standard population-based formula that may not fully account for rare or complex conditions such as severe liver disease, active infection, or recent heart attack. Patients with uncommon conditions are encouraged to discuss their individual risk with their surgical team for a more complete assessment.