The Complementary Value of Absolute Coronary Flow in the Assessment of Patients with Ischaemic Heart Disease (the...

Area of Science:

• Cardiology
• Medical Imaging
• Physiology

Background:

• Fractional flow reserve (FFR) is the gold standard for assessing coronary artery disease (CAD).
• FFR quantifies coronary blood flow (CBF) relative to a theoretical normal, but its accuracy in predicting absolute CBF changes is not well understood.
• Current diagnostic methods for CAD rely heavily on FFR, necessitating validation of its predictive capabilities.

Purpose of the Study:

• To compare fractional CBF measurements with absolute CBF (aCBF) derived from computational analysis.
• To evaluate the accuracy of FFR in predicting actual CBF changes across various arterial conditions.
• To determine the clinical utility of aCBF assessment in complementing FFR, especially in ambiguous cases.

Main Methods:

• A computational method was used to measure aCBF (in mL/min) during standard angiography and pressure-wire assessment.
• Data were collected from 203 diseased arteries across 143 patients.
• Correlation and concordance analyses were performed between FFR-derived fractional CBF and measured aCBF.

Main Results:

• A strong correlation (r=0.89) and substantial agreement (Cohen's Kappa=0.71) were observed between fractional CBF and aCBF.
• High concordance was found when FFR >0.80 (91%), decreasing in lower FFR ranges (e.g., 62% for FFR 0.75-0.80).
• Discordance was linked to factors like coronary microvascular resistance and vessel characteristics, which FFR does not account for.

Conclusions:

• Absolute CBF assessment using computational methods complements FFR in evaluating coronary blood flow.
• aCBF measurement may be particularly valuable for cases falling within the FFR 'grey-zone' (typically 0.75-0.80).
• Integrating aCBF assessment could refine the diagnosis and management of coronary artery disease.