The fractional flow reserve as a criterion to intervention in patients with 50% LAD stenoses and impaired myocardial perfusion

Background: A fractional flow reserve (FFRmyo) <0.75 is a well validated pa rameter for significance of coronary stenoses in cases of normal myocardial function. We used the FFRmyo limit in patients with impaired myocardial pe rfusion by myocardial infarction and/or hypertension for intermediate steno ses of the LAD for decision to PTCA and checked the indication by clinical follow-up. Methods: In 20 pts (5 women) with chest pain and visual 50 D% LAD stenoses, the FFRmyo was obtained by using a RADI-Pressure-Wire, the CFR by a densit ometric technique (HODGSON), and the geometry of stenosis (minimal lumen di ameter and diameter stenosis) by quantitative coronary angiography (QCA). E F and the kinetics of the anterolateral wall (expressed as radial shortenin g fraction) were measured by laevography. Results: The mean age of our 20 pts. was 59.4 years: 13 of the pts. (65%) h ad a history of hypertension, 9 (45%) pts. a history of myocardial infarcti on. The mean diameter stenosis was 50.8%. The mean value of CFR was 2.9. Th e FFRmyo ranged from 0.66 to 0.90, the mean value was 0.78. The 12 pts. wit h FFRmyo greater than or equal to 0.75 (60%, group A) were treated with the usual antianginal medications. A PTCA was performed only in patients with FFRmyo <0.75 (N=8 (40%), group B). Except for one pt. with instent restenos is, in the 7 pts. with denovo stenoses stent implantation was performed. Si gnificant differences between the groups A and B were seen only for the tot al number of myocardial infarctions (8/12 vs. 1/8) and diameter stenosis (4 8.5% vs. 54.3%). All lesions of group B had a diameter stenosis of 50% or h igher. CFR correlated significantly with the radial shortening fraction (r= 0.75), minimal lumen diameter (r=-0.51) and diameter stenosis (r=-0.46). FF Rmyo correlated with diameter stenosis (r=-0.47) only. All pts. treated wit h PTCA were primarily free of pain or reduced angina at least 1 CCS stage; only one developed an angina due to a restenosis (74D%) 2 months after PTCA and stent implantation. The pts. of group A did not get worse, nor were th ey readmitted within 6 to 13 months after catheterization. Conclusions: Pts. with 50 D% stenoses, impaired myocardial perfusion and FF Rmyo <0.75 had a good long-term benefit concerning clinical and angiographi c result. No pts. with FFRmyo <0.75 had a D% lower than 50; therefore, the PTCA of intermediate stenoses without quantification must be avoided. CFR i s not helpful for a decision to PTCA in such cases, because a normal value of CFR is relevant only.