Safety of Lesion Deferral with iFR or FFR in Both Stable and Acute Patients

Overall, deferral of lesion revascularization is equally safe with both fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR), with a low rate of events of about 4%. Lesions were more frequently deferred when iFR (as opposed to FFR) was used for functional assessment. Among patients with deferred lesions, acute patients experienced significantly more events than stable chronic patients.

This study analyzed the safety of lesion deferral in the randomized populations (n = 4486) of the DEFINE-FLAIR (Functional Lesion Assessment of Intermediate Stenosis to Guide Revascularisation) and iFR-SWEDEHEART (Instantaneous Wave-Free Ratio Versus Fractional Flow Reserve in Patients With Stable Angina Pectoris or Acute Coronary Syndrome) trials.

Patients were stratified according to whether the revascularization decision was made on the basis of iFR or FFR and to clinical presentation (acute coronary syndrome and stable chronic disease).

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The primary endpoint was a composite of major adverse events (all-cause death, non-fatal infarction, and unplanned revascularization at one year).

Coronary revascularization was deferred in 2130 total patients: 1117 patients (50%) in the iFR group and 1013 patients (45%) in the FFR group (p < 0.01).

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At 1 year, the rate of events in the population with deferred vessels was similar between the iFR and FFR groups (4.12% vs. 4.05%; p = 0.6). Among the deferred population, clinical presentation as acute coronary syndrome was associated with more events compared with chronic stable patients (5.91% vs. 3.64%; p = 0.04).

Conclusion

Deferral of revascularization is equally safe with both iFR and FFR, with a low event rate of around 4%. Lesions were more commonly deferred when iFR was used. After lesion deferral, patients with an acute coronary syndrome experienced more combined events than patients with stable chronic angina.

Original title: Safety of the Deferral of Coronary Revascularization on the Basis of Instantaneous Wave-Free Ratio and Fractional Flow Reserve Measurements in Stable Coronary Artery Disease and Acute Coronary Syndromes.

Reference: Javier Escaned et al. J Am Coll Cardiol Intv 2018; 11:1437-49.

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