[Fractional flow reserve as a deciding criterion for intervention in patients with 50% coronary stenoses and impaired myocardial perfusion].

BACKGROUND

A fractional flow reserve (FFRmyo) < 0.75 is a well validated parameter for significance of coronary stenoses in cases of normal myocardial function. We used the FFRmyo limit in patients with impaired myocardial perfusion by myocardial infarction and/or hypertension for intermediate stenoses 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 densitometric technique (HODGSON), and the geometry of stenosis (minimal lumen diameter and diameter stenosis) by quantitative coronary angiography (QCA). EF and the kinetics of the anterolateral wall (expressed as radial shortening fraction) were measured by laevography.

RESULTS

The mean age of our 20 pts. was 59.4 years: 13 of the pts. (65%) had a history of hypertension, 9 (45%) pts. a history of myocardial infarction. The mean diameter stenosis was 50.8%. The mean value of CFR was 2.9. The FFRmyo ranged from 0.66 to 0.90, the mean value was 0.78. The 12 pts. with FFRmyo > or = 0.75 (60%, group A) were treated with the usual anti-anginal medications. A PTCA was performed only in patients with FFRmyo < 0.75 (N = 8 (40%), group B). Except for one pt. with instent restenosis, in the 7 pts. with denovo stenoses stent implantation was performed. Significant differences between the groups A and B were seen only for the total number of myocardial infarctions (8/12 vs. 1/8) and diameter stenosis (48.5% vs. 54.3%). All lesions of group B had a diameter stenosis of 50% or higher. CFR correlated significantly with the radial shortening fraction (r = 0.75), minimal lumen diameter (r = -0.51) and diameter stenosis (r = -0.46). FFRmyo correlated with diameter stenosis (r = -0.47) only. All pts. treated with PTCA were primarily free of pain or reduced angina at least 1 CCS stage; only one developed an angina due to a restenosis (74 D%) 2 months after PTCA and stent implantation. The pts. of group A did not get worse, nor were they readmitted within 6 to 13 months after catheterization.

CONCLUSIONS

Pts. with 50 D% stenoses, impaired myocardial perfusion and FFRmyo < 0.75 had a good long-term benefit concerning clinical and angiographic 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 is not helpful for a decision to PTCA in such cases, because a normal value of CFR is relevant only.