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. Author manuscript; available in PMC: 2016 Jul 13.
Published in final edited form as: Circ Cardiovasc Interv. 2015 Jun;8(6):e001715. doi: 10.1161/CIRCINTERVENTIONS.114.001715

Figure 5.

Figure 5

Estimating the change in hyperemic flow velocity based on the δ or change in pressure-only index after percutaneous coronary intervention (PCI). Pressure-only indices increase after PCI and demonstrate a curvilinear relationship with the change in resting and hyperemic flow velocity. For a change in instantaneous wave-free ratio (iFR), the change in wave-free flow velocity was predicted by the curve y=7.522x3−2.863x2+0.6754x+1.1943, whereas the change in hyperemic flow velocity was predicted by the curve y=18.96x3−11.94x2+5.6048x+1.304. For fractional flow reserve (FFR), the change in resting wave-free flow velocity was predicted by a curve y=20.7x3−9.1852x2+2.0422x+1.1019, whereas the change in hyperemic flow was y=17.175x3−0.1665x2−3.0192x+1.0898.