We tested whether fractional flow reserve (FFR) discriminates between subop
timally and optimally deployed stents. Latex tubes (diameter circle divide
= 4 mm) with diameter stenosis 40% (n = 3), 50% (n = 3) and 60% (n = 3) wer
e tested in a pulsatile flow system, using water. Measurements were done at
baseline (n = 9; FFR/QCA) and after suboptimal (SOD; 3-mm balloon at 8 atm
) and optimal (OD; 4 mm balloon at 16 atm) deployment of a 35-mm stent (n =
6; FFR/OCA/IVUS). Varying Q from 150 to 50 ml/min increased FFR by 2-7%. C
onversely, at 100 ml/min, FFR increased by only 0.8% from SOD to OD (P < 0.
05). Extrapolating data to blood flow, the gain in FFR from SOD to OD is le
ss than 5% for Q = 100 ml/min, while FFR may increase by 15-20% by changes
in blood flow from 50 to 150 ml/min. We conclude that IVUS and OCA are more
appropriate for the assessment of optimal stent deployment. (C) 2001 Wiley
-Liss, Inc.