Prospective Evaluation of the Impact of Side-Holes and Guide-Catheter Disengagement From the Coronary Ostium on Fractional Flow Reserve Measurements.

We prospectively examined the impact of side-holes and guide-catheter disengagement on fractional flow reserve (FFR) measurements.Twenty-five patients undergoing clinically indicated FFR measurement for intermediate coronary artery stenosis were enrolled. Four FFR measurements were made in random order during intravenous adenosine infusion with: (a) an engaged side-hole guide catheter; (b) a disengaged side-hole guide catheter; (c) an engaged non-side-hole guide catheter; and (d) disengaged non-side-hole guide catheter.Mean patient age was 65 ± 9 years and 100% were men. The mean distal poststenotic pressure/proximal aortic pressure (Pd/Pa) at baseline was 0.93 ± 0.05 mm Hg. Using intravenous adenosine infusion, the mean FFR measured with engaged vs disengaged non-side-hole guide catheters was 0.87 ± 0.09 vs 0.83 ± 0.10, respectively (mean difference, 0.039 ± 0.04; P<.001). The mean FFR with engaged vs disengaged side-hole guide catheters was 0.85 ± 0.10 vs 0.83 ± 0.10 (mean difference, 0.020 ± 0.02; P<.001). The mean difference in FFR measurements was 0.024 ± 0.03 (P<.001) among engaged guide catheters and 0.005 ± 0.03 (P=.47) among disengaged guide catheters.When FFR measurements are performed with engaged guide catheters, side-hole catheters provide lower measurements. When FFR measurements are obtained with disengaged guide catheters, they are even lower and similar between guide catheter types.