What does a focal drop off of Fractional Flow Reserve Computed Tomography (FFRCT) values from 0.792 to 0.67, without visible stenosis on Coronary Computed Tomography Angiography (CCTA), and a gradual decline of FFRCT values in distal arterial segments, suggest in terms of coronary artery disease?

FFRCT Findings Without Visible Stenosis: Interpretation and Clinical Significance

A focal drop in FFRCT from 0.792 to 0.67 without corresponding stenosis on CCTA, combined with gradual distal FFRCT decline, indicates diffuse atherosclerotic disease affecting coronary hemodynamics—this pattern should prompt medical optimization rather than revascularization, as these findings represent microvascular dysfunction and/or diffuse plaque burden that cannot be addressed with focal intervention.

Understanding the Focal FFRCT Drop Without Visible Stenosis

Discordance Between Anatomy and Physiology

• FFRCT can show abnormal values (≤0.80) even with mild or no visible stenosis on CCTA, representing a known limitation where physiologic significance doesn't always correlate with anatomic severity 1
• This discordance occurs because FFRCT modeling captures hemodynamic effects that may not be visually apparent on anatomic imaging, including:
  • Diffuse atherosclerotic changes causing increased resistance along the vessel length 2
  • Microvascular dysfunction affecting distal coronary flow 2
  • Computational modeling artifacts in vessels with complex geometry 1

Clinical Interpretation of Your Specific Values

• Your FFRCT drop from 0.792 to 0.67 crosses the critical threshold of 0.75-0.80, placing the distal value in the clearly abnormal range that typically indicates hemodynamically significant disease 2
• However, the absence of focal stenosis on CCTA makes this finding consistent with diffuse disease rather than a discrete lesion amenable to intervention 1

Gradual Distal FFRCT Decline: The Diffuse Disease Pattern

Characteristic Features of Diffuse Atherosclerosis

• In arteries with diffuse atherosclerotic disease, coronary pressure noticeably declines along the length of the artery, unlike normal vessels where FFR remains 0.97 ± 0.02 2
• In nonstenotic arteries from patients with atherosclerosis elsewhere, FFR averages 0.89 ± 0.08, with frank ischemic values <0.75 occurring in 8% of cases despite no focal stenosis 2
• Gradually decreasing FFRCT values at the distal vessel without a proximal focal lesion is specifically recognized as a pattern of diffuse atherosclerosis 1

Why This Pattern Occurs

• Diffuse diameter changes along the vessel length increase resistance, causing progressive pressure loss that manifests as gradual FFRCT decline 2
• The gradual decline indicates that no single location accounts for the hemodynamic abnormality—the entire vessel segment contributes to flow limitation 2
• This pattern reflects atherosclerotic plaque burden offset by vessel remodeling that preserves lumen diameter but still impairs flow dynamics 2

Clinical Management Implications

When Revascularization Is NOT Appropriate

• FFR should not be considered a marker for revascularization in patients with diffuse coronary atherosclerosis showing a graded, continuous pressure fall along the arterial length 2
• In cases where gradual decline of pressure occurs over a very long segment, interventional treatment is not possible, and medical treatment (or bypass surgery) should be elected 2
• Your pattern—focal drop without visible stenosis plus gradual distal decline—falls into this category where stenting would not address the underlying diffuse process

Recommended Management Strategy

• Aggressive medical therapy is the primary treatment approach, including:

  • Aspirin for antiplatelet effect 2
  • High-intensity statin therapy (e.g., simvastatin 40mg or equivalent) 2
  • Antianginal medications as needed for symptom control 2
  • Risk factor modification (blood pressure, diabetes control, smoking cessation)

• Consider invasive FFR measurement if revascularization is being contemplated, as FFRCT has known limitations and invasive FFR remains the gold standard for decision-making 2

• Functional testing with stress imaging may help assess the clinical significance of the abnormal FFRCT values and guide intensity of medical therapy 2

Important Caveats and Pitfalls

FFRCT Limitations in This Context

• FFRCT has not been validated in certain conditions including diffuse disease patterns, and caution is warranted in interpretation 1
• The computational modeling may be affected by:
  • Vessel length (longer vessels show greater FFRCT decline even without disease) 3, 4
  • Bifurcation angles (larger angles cause energy loss and FFRCT decline) 4
  • Left ventricular mass and microvascular function 3

Differential Considerations

• Microvascular dysfunction can cause abnormal distal FFRCT with normal epicardial arteries, particularly in patients with:

  • Hypertension and left ventricular hypertrophy 5
  • Diabetes mellitus
  • Female sex (women more likely to have higher FFR for same anatomic stenosis) 2

• Consider measuring coronary flow reserve (CFR) and index of microvascular resistance (IMR) if invasive assessment is performed, as these provide complementary information about microvascular function 2

When to Reconsider the Diagnosis

• If symptoms are severe or refractory to medical therapy, invasive coronary angiography with pressure wire assessment can definitively characterize the disease pattern and identify any focal component that might benefit from intervention 2
• Pullback pressure recordings during invasive FFR are particularly useful for distinguishing focal from diffuse disease and identifying specific treatment targets 2