Pooled Analysis of DEFINE-FLAIR and iFR-SWEDEHEART

Study Questions:

What are the clinical outcomes of patients deferred from coronary revascularization on the basis of instantaneous wave-free ratio (iFR) or fractional flow reserve (FFR) measurements in stable angina pectoris (SAP) and acute coronary syndromes (ACS)?

Methods:

The investigators analyzed the safety of deferral of coronary revascularization in the pooled per-protocol population (n = 4,486) 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) randomized clinical trials. Patients were stratified according to revascularization decision making on the basis of iFR or FFR and to clinical presentation (SAP or ACS). The primary endpoint was major adverse cardiac events (MACE), defined as the composite of all-cause death, nonfatal myocardial infarction, or unplanned revascularization at 1 year.

Results:

Coronary revascularization was deferred in 2,130 patients. Deferral was performed in 1,117 patients (50%) in the iFR group and 1,013 patients (45%) in the FFR group (p < 0.01). At 1 year, the MACE rate in the deferred population was similar between the iFR and FFR groups (4.12% vs. 4.05%; fully adjusted hazard ratio, 1.13; 95% confidence interval, 0.72-1.79; p = 0.60). A clinical presentation with ACS was associated with a higher MACE rate compared with SAP in deferred patients (5.91% vs. 3.64% in ACS and SAP, respectively; fully adjusted hazard ratio, 0.61 in favor of SAP; 95% confidence interval, 0.38-0.99; p = 0.04).

Conclusions:

Overall, deferral of revascularization is equally safe with both iFR and FFR, with a low MACE rate.

Perspective:

This study reports that overall, the revascularization of intermediate stenoses in patients with SAP can be safely deferred on the grounds of iFR or FFR measurements. In patients with ACS, deferral was associated with more cardiovascular events at follow-up, compared to patients with SAP. Overall, these data suggest that deferral of coronary revascularization by either iFR or FFR methods is equally safe in SAP, but not recommended in ACS patients.

Clinical Topics: Acute Coronary Syndromes, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Prevention, Stable Ischemic Heart Disease, Atherosclerotic Disease (CAD/PAD), Cardiac Surgery and Arrhythmias, Cardiac Surgery and SIHD, Interventions and ACS, Interventions and Coronary Artery Disease, Chronic Angina

Keywords: Acute Coronary Syndrome, Angina, Stable, Constriction, Pathologic, Coronary Artery Disease, Fractional Flow Reserve, Myocardial, Myocardial Infarction, Myocardial Ischemia, Myocardial Revascularization, Secondary Prevention


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