Relationship between coronary volume, myocardial mass, and post‐PCI fractional flow reserve

Background Fractional flow reserve (FFR) measured after percutaneous coronary intervention (PCI) carries prognostic information. Yet, myocardial mass subtended by a stenosis influences FFR. We hypothesized that a smaller coronary lumen volume and a large myocardial mass might be associated with lower post‐PCI FFR. Aim We sought to assess the relationship between vessel volume, myocardial mass, and post‐PCI FFR. Methods This was a subanalysis with an international prospective study of patients with significant lesions (FFR ≤ 0.80) undergoing PCI. Territory‐specific myocardial mass was calculated from coronary computed tomography angiography (CCTA) using the Voronoi's algorithm. Vessel volume was extracted from quantitative CCTA analysis. Resting full‐cycle ratio (RFR) and FFR were measured before and after PCI. We assessed the association between coronary lumen volume (V) and its related myocardial mass (M), and the percent of total myocardial mass (%M) with post‐PCI FFR. Results We studied 120 patients (123 vessels: 94 left anterior descending arteries, 13 left Circumflex arteries, 16 right coronary arteries). Mean vessel‐specific mass was 61 ± 23.1 g (%M 39.6 ± 11.7%). The mean post‐PCI FFR was 0.88 ± 0.06 FFR units. Post‐PCI FFR values were lower in vessels subtending higher mass (0.87 ± 0.05 vs. 0.89 ± 0.07, p = 0.047), and with lower V/M ratio (0.87 ± 0.06 vs. 0.89 ± 0.07, p = 0.02). V/M ratio correlated significantly with post‐PCI RFR and FFR (RFR r = 0.37, 95% CI: 0.21−0.52, p