What scoring system is used to predict mortality after valve surgery, such as EuroSCORE (European System for Cardiac Operative Risk Evaluation)?

Scoring Systems for Predicting Mortality After Valve Surgery

The EuroSCORE (European System for Cardiac Operative Risk Evaluation) is the most widely used and validated scoring system for predicting mortality after valve surgery, with both additive and logistic versions available. 1

Main Risk Stratification Systems

• The EuroSCORE is the primary scoring system used worldwide to predict operative mortality in heart valve surgery, combining multiple risk factors into a single score 1
• Two versions of EuroSCORE exist:
  • Additive EuroSCORE: Simple point-based system (easier to calculate at bedside) 1
  • Logistic EuroSCORE: More complex mathematical model that may provide better calibration for high-risk patients 1
• The Society of Thoracic Surgeons (STS) score is another widely used system, specifically designed for valve surgery with 24 covariates, making it more specific to VHD but less user-friendly than EuroSCORE 1

EuroSCORE Risk Factors and Scoring

EuroSCORE includes the following risk factors 1:

• Patient-related factors:

  • Age (points increase with each 5-year increment from age 60)
  • Female sex (1 point)
  • Chronic pulmonary disease (1 point)
  • Extracardiac arteriopathy (2 points)
  • Neurological dysfunction (2 points)
  • Previous cardiac surgery (3 points)
  • Serum creatinine >200 mM/L (2 points)
  • Active endocarditis (3 points)
  • Critical preoperative state (3 points) 1

• Cardiac-related factors:

  • Unstable angina requiring IV nitrates (2 points)
  • Left ventricular dysfunction (moderate: 1 point, poor: 3 points)
  • Recent myocardial infarction (<90 days, 2 points)
  • Pulmonary hypertension (2 points) 1

• Operation-related factors:

  • Emergency surgery
  • Other than isolated CABG
  • Surgery on thoracic aorta
  • Post-infarct septal rupture 1

Performance and Limitations

• EuroSCORE has demonstrated good discrimination (ability to differentiate between low and high-risk patients) but may have calibration issues (accuracy in predicting actual risk) 1
• The logistic EuroSCORE tends to overestimate mortality in high-risk patients, which is an important limitation when making clinical decisions 1
• The EuroSCORE II was developed to address these limitations and improve calibration, particularly for high-risk patients 1, 2
• STS score has the advantage of being specific to valve heart disease but is more complex to calculate 1

Clinical Application

• Risk scores should not be used in isolation but integrated with clinical judgment and other methods of risk assessment 1
• The predictive performance of risk scores can be improved by:
  • Recalibration over time (as with EuroSCORE II)
  • Adding variables that assess functional and cognitive capacities
  • Designing specific risk scores for particular subgroups (elderly, combined valve and coronary surgery) 1
• Operative mortality rates vary by procedure type, with combined valve and CABG procedures carrying higher risk than isolated valve procedures 1

Regional Variations

• Despite demographic differences between Europe and North America, EuroSCORE has been validated and performs well in North American populations 3
• Performance may vary in other populations - for example, studies show that EuroSCORE may not accurately predict mortality in Chinese valve surgery patients 4
• Regional scoring systems like SinoSCORE have been developed to better predict outcomes in specific populations 4

Long-term Prediction

• Beyond its original purpose of predicting in-hospital mortality, EuroSCORE has also shown value in predicting long-term mortality after valve surgery 5
• Higher EuroSCORE quartiles correlate with significantly lower 5-year survival rates, making it useful for long-term risk stratification 5

Common Pitfalls

• Relying solely on a single number from risk scores to determine treatment decisions 1
• Failing to recognize that risk scores have poorer discrimination in certain subgroups 6
• Not accounting for factors beyond the scoring systems, such as frailty in elderly patients, which significantly impacts outcomes 6
• Underuse of therapeutic intervention in high-risk symptomatic patients despite guideline recommendations 1