Abstract 14944: Improved Assessment of Coronary Artery Stenosis Severity Using Combined Anatomical and Functional Endpoints: A Clinical Study
Introduction: During cardiac catheterization, functional severity of blockages is assessed using diagnostic parameters, like Fractional Flow Reserve (FFR, pressure based) and Coronary Flow Reserve (CFR, flow based). However, the complex hemodynamics of stenosis might not be sufficiently explained by either pressure or flow alone, particularly in the case of intermediate stenosis. Therefore, based on fluid dynamic principles, we have defined two parameters, Pressure Drop Coefficient (CDP, functional endpoint), based on both pressure and flow, and Lesion Flow Coefficient (LFC), that combines anatomical (area stenosis, %AS) and functional endpoints (Table 1). Hypothesis: We hypothesize that the CDP will correlate better when FFR and CFR are combined and the LFC will correlate when FFR, CFR and %AS are combined.
Methods: The protocol for this clinical study was approved by the IRB at the University of Cincinnati and Veteran Affairs Medical Center. Patients with reversible perfusion defects as per SPECT scan were consented and enrolled in the study. Simultaneous pressure and flow readings, at baseline and adenosine induced hyperemia, were obtained using a 0.014” dual sensor Combowire® (Volcano Therapeutics Inc.) from 20 vessels. %AS was obtained from quantitative coronary analysis using edge detection technique (GE Centricity CA100, GE healthcare). Regression analysis was done using SAS® software. p < 0.05 was used for statistical significance.
Results: The correlation coefficient (r) of CDP with FFR (r = 0.55) and CFR (r = 0.54) increased when the parameters were combined (r = 0.65, p < 0.05). The combined correlation of LFC with FFR, CFR and %AS was higher (0.82, p < 0.05) in comparison to its individual correlations (FFR, r = 0.16; CFR, r = 0.33).
Conclusion: Functional endpoint, CDP correlated significantly with FFR and CFR. LFC, a combined functional and anatomical endpoint, correlated significantly with FFR, CFR and %AS.
- © 2012 by American Heart Association, Inc.