The TARGET FFR and DEFINE-FLOW studies were presented at TCT 2020 which have offer a deeper perspective on the value of FFR, not only before but also after PCI.
TARGET FFR
The TARGET FFR included 260 patients randomized after angiographically successful PCI to an FFR guided optimization vs. blinded FFR assessment strategies.
In the guided group the FFR pullback of stented vessels found targets for further optimization in 46% of patients which led to additional post dilation or stenting of other vessel segments in 66% of cases, resulting in increased mean post-PCI FFR from 0.76 to 0.82, with a larger increase seen with stenting rather than with post dilation.
This optimization prolonged the procedure, and increased radiation exposure, contrast volume and adenosine dose, even though this did not seem to translate into clinical adverse events.
Achieving final post-PCI FFR ≥0.90 was numerically more frequent in the optimization arm (38.1% vs 28.1%; p=0.099). The number of patients with final FFR value <0.8 did result significantly lower (18.6% vs 29.8%; p=0.045).
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As in previous registries, FFR value resulted lower when the artery to treat was the anterior descending vs. the left circumflex or the right coronary arteries.
It is distressing the number of patients in the angiography guided arm assessed by blinded FFR who completed the procedure with suboptimal values.
DEFINE-FLOW
In the past few years there has been a growing interest in better understanding microvascular abnormalities, and the second study presented (DEFINE-FLOW) is one of the first to examine this point.
The hypothesis behind this study was that treated patients who had FFR < 0.8 but intact CRF (>2) would have results comparable to those with normal FFR and CFR values.
The DEFINE-FLOW included 430 patients with 533 stable lesions that underwent simultaneous FFR and CFR assessment. Only lesions with low FFR and CFR underwent PCI. All other combinations, including FFR <0.8 but conserved CFR were deferred and treated medically.
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At 2 years, the primary endpoint of all-cause death, MI, and revascularization rates differed across the four possible combinations. The best prognosis was for patients with negative FFR and CFR and the highest rate of events was on the opposite side, patients with positive FFR and CFR (<0.8 and <0.2, respectively) who underwent PCI.
Lesions with FFR <0.8 and normal CFR showed a 5% higher events rate vs. patients with normal values.
In other words, FFR value does matter, even with normal CFR.
Original Title: TARGET FFR: A randomized trial of physiology-guided PCI optimization y DEFINE-FLOW: an observational study of deferred lesions after FFR and CFR assessment.
Reference: El estudio TARGET FFR fue presentado por el Dr Collison D y el estudio DEFINE-FLOW por el Dr Johnson N. Ambos trabajos fueron presentados en el TCT 2020 virtual.
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