5-year follow up of the DEFINE FLAIR Trial

Reviewer: Dr. M. Fatih Kaleli

Presentation:EUROPCR 2023

Background

In the last 20 years, physiological measurements made during coronary interventions have begun to guide coronary interventions. Recent studies have shown that the FFR method is more effective in evaluating intervention in coronary artery lesions compared to angiographic imaging alone. The FFR method enables the determination of the pressure gradient in the lesion area at the time of maximal blood flow by means of a pressure-measuring guide wire. Hyperemic agents such as adenosine are routinely used for maximal blood flow. IFR method is another physiological method that shows coronary artery stenosis, like the FFR method. Hyperemic agents are not used in the IFR method.

The IFR method is widely utilized for the functional evaluation of epicardial stenoses. The aim of the DEFINE-FLAIR study is to compare the IFR method used for coronary revascularization with the FFR method in terms of efficacy and safety. In the 1-year results of the DEFINE-FLAIR study, when the primary endpoint was MACE, no significant difference was found between the IFR group and the FFR group. In this study, 5-year results of coronary interventions guided by FFR and IFR are described.

Method

The DEFINE-FLAIR study was a multicenter, international, randomized study that included 2492 patients from 49 center and 17 countries. FFR and IFR ratio randomized to 1:1. Coronary Intervention had when with 0.80 ≤ in the FFR arm and 0.89 ≤ in the IFR arm. All-cause of deaths, myocardial infarction, and unplanned eclipses were described as MACE.

Results

When the endpoint of the study was evaluated as MACE in the 5-year follow-up results, no significant difference was found in the FFR and IFR arms. (IFR 21.1% vs FFR 18.4% p:0.07). Non-fatal myocardial infarction (IFR 6.28% vs FFR 6.24% p:0.80) or unplanned revascularization (IFR 11.9% vs FFR 12.2% p:0.96) was observed in both study arms at a similar rate. All-cause of mortality was observed more frequently in the IFR arm (IFR 9% vs FFR 6.2% p:0.01).

Interpretation

No significant difference was found in the 5-year follow-up of patients who did not undergo coronary revascularization after FFR or IFR. Except for the secondary endpoint of mortality, the 5-year outcomes observed in the DEFINE FLAIR study closely resemble those reported in its counterpart study IFR SWEDEHEART.