QFR  vs. FFR for Coronary Revascularization Guidance

February 25th, 2025

Background

Fractional flow reserve (FFR) is the gold standard for guiding revascularization in patients with intermediate coronary stenoses, as it reduces unnecessary interventions and improves clinical outcomes. However, FFR requires pressure wires, full anticoagulation, and catheter placement, adding cost and procedural risk.

Quantitative flow ratio (QFR), an angiography-based computational method, offers a noninvasive alternative by analyzing coronary angiograms without pressure wires. The FAVOR III China trial showed that QFR was superior to routine angiographic guidance, leading to its Class I recommendation in the 2024 European Society of Cardiology (ESC) guidelines for managing chronic coronary syndromes.

The FAVOR III Europe trial aimed to directly compare QFR and FFR in guiding coronary revascularization based on clinical outcomes, rather than numerical concordance.

Study Design (FAVOR III Europe Trial)

• Multicenter, randomized, noninferiority trial across 34 centers in 11 European countries.
• 2,000 patients with intermediate coronary stenoses were randomly assigned to QFR- or FFR-based revascularization guidance.
• Primary endpoint:
  • Composite of all-cause death, myocardial infarction (MI), and unplanned revascularization at 12 months.
• Revascularization criteria:
  • QFR: ≤ 0.80
  • FFR: ≤ 0.80

Patient Characteristics

• Median age: 66 years
• 23% female
• 66% had chronic coronary disease
• 25% were undergoing non-culprit evaluation post-acute coronary syndrome intervention
• 8% had non-ST-elevation myocardial infarction at randomization

Key Findings

• QFR overestimated lesion significance, identifying 46.2% as significant vs. 38.2% in the FFR group.
• 27% more stents were used in the QFR group (823 vs. 650).
• Procedure time, contrast volume, and complication rates were similar between groups, but fluoroscopy time was longer in the FFR group.

Primary Endpoint (12-month Clinical Outcomes)

• Composite of all-cause death, myocardial infarction, and unplanned revascularization:
  • QFR group: 6.7%
  • FFR group: 4.2%
  • Hazard ratio (HR): 1.63 (95% CI, 1.11-2.41; two-sided P = 0.013)
  • QFR failed noninferiority (prespecified margin: 3.4%).
• Myocardial infarction rates:
  • QFR: 3.7%
  • FFR: 2.0%
  • HR: 1.84 (95% CI, 1.07-3.17; P = 0.028)
• Unplanned revascularization trended higher in the QFR group, despite increased stenting during the index procedure.

Conclusions

• QFR failed to demonstrate noninferiority to FFR.
• Higher stent use in the QFR group did not translate into improved outcomes, and MI rates were higher.
• FFR remains the preferred method when available, while QFR may still be useful in settings without access to FFR/iFR.

Clinical Implications

1. QFR should not replace FFR for revascularization decisions in centers where FFR or iFR is available.
2. Overestimation of lesion severity by QFR may lead to unnecessary stenting and increased MI risk.
3. QFR may still be useful in diagnostic-only labs where FFR/iFR are unavailable, but its role remains uncertain.

Future trials (ALL-RISE, FAST III, PIONEER-IV) are expected to refine the role of angiography-based computational techniques in clinical practice.

For a more in-depth look at the data, click here.