Is a functional coronary angiogram (FCA) a cost-effective tool for diagnosing coronary artery disease (CAD)?

Cost-Effectiveness of Functional Coronary Angiography for Cardiovascular Diagnosis

Functional coronary angiography (FCA) is cost-effective for diagnosing coronary artery disease (CAD) only in specific clinical scenarios, particularly in patients with intermediate coronary stenoses where determining functional significance impacts revascularization decisions.

Diagnostic Approach for CAD: Cost-Effectiveness Considerations

Initial Diagnostic Testing

• For patients with low to moderate pre-test probability of CAD (5-50%), coronary CT angiography (CCTA) is recommended as the most cost-effective initial diagnostic test 1
• For patients with higher pre-test probability (>50-85%), non-invasive functional imaging tests are more cost-effective as initial tests 1
• Invasive coronary angiography with functional assessment should be reserved for specific scenarios:
  • Patients with high clinical likelihood of disease (>85%)
  • Severe symptoms refractory to medical therapy
  • Angina at low exercise levels
  • High event risk 1

Role of Functional Coronary Angiography

When FCA is Cost-Effective:

• During invasive coronary angiography, selective assessment of functional severity of intermediate stenoses is strongly recommended (Class I recommendation) to guide revascularization decisions 1
• Appropriate functional assessment methods during angiography include:
  • FFR/iFR (significant ≤0.8 or ≤0.89, respectively) - Class I, Level A evidence
  • QFR (significant ≤0.8) - Class I, Level B evidence 1
  • CFR/HSR/CFC as complementary investigations - Class IIa, Level B evidence 1

When FCA is Not Cost-Effective:

• Systematic and routine wire-based coronary pressure assessment of all coronary vessels is explicitly not recommended (Class III, Level A evidence) 1
• This indicates that indiscriminate use of functional testing during angiography increases costs without proportional clinical benefit 1

Comparative Cost-Effectiveness of Diagnostic Strategies

• The cost-effectiveness of diagnostic strategies depends on the pre-test probability of significant CAD:

  • For lower prevalence populations, non-invasive testing followed by selective angiography is more cost-effective
  • For higher prevalence populations, direct invasive testing with functional assessment becomes more cost-effective 2

• A comparative analysis showed that CMR followed by selective angiography was more cost-effective than angiography with FFR below certain CAD prevalence thresholds:

  • 62% in Switzerland
  • 65% in Germany
  • 83% in the UK
  • 82% in the US 2

Practical Considerations for FCA Implementation

Benefits of FCA

• Provides both anatomical and functional assessment in a single procedure
• Particularly valuable for evaluating borderline lesions
• Reduces need for additional non-invasive functional tests
• Improves precision in identifying hemodynamically significant stenoses 3

Limitations of FCA

• Invasive procedure with associated risks (1.5% incidence of complications) 4
• Higher upfront costs compared to non-invasive testing
• Requires specialized equipment and expertise
• Not necessary for all patients with suspected CAD 4

Cost-Effectiveness Pitfalls to Avoid

1. Overuse in low-risk patients: Approximately 45% of elective cardiac catheterizations do not detect clinically significant stenoses, indicating potential overuse 1

2. Underutilization of functional assessment: Angiography alone provides only anatomic data without reliable indication of functional significance, potentially leading to unnecessary revascularizations 4

3. Ignoring pre-test probability: Failing to consider pre-test probability when selecting diagnostic tests can lead to inefficient resource utilization 1

4. Routine "triple rule out" approaches: General protocols that evaluate coronary arteries, aorta, and pulmonary arteries simultaneously are less cost-effective than tailored imaging protocols focused on the most likely diagnosis 1

Optimal Diagnostic Algorithm for CAD

1. Initial risk stratification based on clinical assessment, symptoms, and basic testing
2. For low-moderate risk patients (5-50% pre-test probability): Start with CCTA
3. For higher risk patients (>50-85%): Consider non-invasive functional imaging first
4. For very high risk (>85%) or severe symptoms: Direct invasive angiography with selective functional assessment
5. For intermediate stenoses found during angiography: Apply functional assessment (FFR/iFR/QFR) to guide revascularization decisions

By following this evidence-based approach, functional coronary angiography can be applied in a cost-effective manner that optimizes both clinical outcomes and resource utilization.