Abstract 3068: Lesion Flow Coefficient: A Novel Diagnostic Index to Assess Coronary Occlusions Using Combined in vivo Measurements of Blood Flow, Pressure Gradient and Area Blockage
Introduction: To delineate epicardial coronary stenosis from microvascular impairment, an index that combines hemodynamic endpoints: pressure gradient (dp) and blood flow with geometric endpoint: percentage area of occlusion is lacking in clinical science. Our recently published lesion flow coefficient (LFC) is the first novel hyperemic index that combines hemodynamic and geometric parameters of coronary stenosis as a single diagnostic endpoint.
Hypothesis: We hypothesize that the LFC, assessed in vivo, shows a significant correlation with fractional flow reserve (FFR) and coronary flow reserve (CFR).
Methods: We used 6 pigs (41±3 kg) for our study. The area of LAD artery was measured with IVUS. Angioplasty balloons were inflated to create desired intraluminal area occlusions. FFR and CFR were measured distal to the balloon at peak hyperemia with 10 mg intracoronary papaverine. LFC was calculated as (percentage area stenosis)/((dp)/(0.5x1.05xV2)1/2), where V was hyperemic velocity adjacent to the balloon. V was calculated as measured peak velocity distal to the balloon divided by area stenosis. The density of blood was 1.05 g/cm3.
Results: Vessel diameter before balloon insertion was 3.37±0.25 mm. Mean CFR, FFR and LFC were 1.51±0.36, 0.63±0.09, and 0.13±0.05, respectively (p<0.001). p<0.05 was considered statistically significant. LFC correlated linearly and significantly with FFR (r<0.71, p<0.001) and CFR (r < 0.88, p<0.001). When LFC was correlated simultaneously with FFR and CFR, r improved to 0.90 (p<0.001).
Conclusion: In conclusion, LFC, assessed in vivo, correlated significantly with FFR and CFR under normal microvascular function.