What validated operative risk scores should be used to assess risk for open aortic surgery?

Risk Scoring for Open Aortic Surgery

While multiple risk scoring systems exist for open aortic surgery, no single validated operative risk score is universally recommended by current major guidelines for comprehensive preoperative risk assessment across all aortic segments. Instead, guidelines emphasize specific clinical risk factors rather than formal scoring systems when determining operative candidacy 1, 2.

Guideline-Based Approach to Risk Assessment

The most recent major aortic guidelines (2024 ESC and 2022 ACC/AHA) do not mandate specific risk scoring systems but instead identify key clinical factors that increase operative mortality:

High-Risk Clinical Features for Open Aortic Surgery

• Advanced age (particularly octogenarians)
• Left ventricular dysfunction (LVEF <40%)
• Chronic kidney disease/preoperative renal dysfunction
• Chronic obstructive pulmonary disease
• Emergency/ruptured presentation

1, 2

Critical Guideline Context

Both the 2024 ESC and 2022 ACC/AHA guidelines emphasize that experienced multidisciplinary aortic teams can achieve excellent outcomes even in high-risk patients with these comorbidities 1, 2. For example, patients with LVEF <40% undergoing thoracoabdominal aortic aneurysm (TAAA) repair showed no increased operative mortality when managed by specialized teams 1.

Available Risk Scoring Systems (Research Evidence)

While not guideline-mandated, several validated scoring systems exist for specific aortic procedures:

For Abdominal Aortic Aneurysm (AAA) Repair:

• Glasgow Aneurysm Score (GAS): Validated with moderate discriminative ability (AUC 0.72-0.84) 3, 4, 5
• Modified Leiden Score (M-LS): Similar performance (AUC 0.70-0.71) 3, 4
• Modified Comorbidity Severity Score (M-CSS): Comparable accuracy (AUC 0.69-0.74) 3, 4
• E-PASS (Estimation of Physiologic Ability and Surgical Stress): Highest discriminative ability for AAA (AUC 0.92) 5
• VGNW (Vascular Governance North West) model: Fair performance (AUC 0.73) 3

For Acute Type A Aortic Dissection:

• EuroSCORE II: Better discriminative power (AUC 0.799) than disease-specific scores 6
• GERAADA Score: Lower discriminative ability (AUC 0.550) despite being disease-specific 6

Critical Limitations and Pitfalls

Major Caveats:

1. Risk scores often overestimate mortality in experienced centers. EuroSCORE and VA CICSP predicted 18-19% mortality but observed mortality was only 8% at specialized centers 7

2. No validated scores exist specifically for thoracoabdominal or descending thoracic aortic surgery in current guidelines

3. Scoring systems developed for cardiac surgery (EuroSCORE II) may not accurately reflect aortic-specific risks, though they show reasonable calibration 6

4. Institution-specific models outperform national models for local decision-making but cannot be used for comparative audit 3

Practical Clinical Algorithm

For preoperative risk stratification in open aortic surgery:

1. Assess the specific clinical risk factors listed above rather than relying solely on numerical scores

2. Consider referral to a multidisciplinary aortic team for patients with multiple comorbidities, as specialized centers achieve significantly better outcomes 1, 2

3. If using risk scores for AAA repair: E-PASS demonstrates superior predictive ability 5, though GAS remains most widely studied 3, 4, 5

4. For acute type A dissection: EuroSCORE II provides better discrimination than disease-specific scores 6

5. Recognize that all existing scores have limitations and should inform but not dictate surgical decision-making, particularly in centers with specialized expertise

Key Takeaway:

Current best practice emphasizes clinical judgment based on specific risk factors and institutional expertise over rigid adherence to risk scoring systems, as guidelines prioritize multidisciplinary team assessment rather than score-based exclusion criteria 1, 2.