Similar long-term outcomes with iFR- vs FFR-guided revascularization

The use of instantaneous wave-free ratio (iFR) to guide revascularization decisions continued to show similar outcomes in terms of all-cause mortality, myocardial infarction (MI), or unplanned revascularization in patients with stable angina or acute coronary syndrome (ACS) compared with fractional flow reserve (FFR) at 5 years, according to the iFR-SWEDEHEART* study presented at TCT 2021.

The study enrolled 2,037 patients with stable angina or ACS and a clinical indication for physiology-guided assessment of coronary lesions, with a recommendation of 30–80 percent stenosis grade. Participants were randomly assigned to the iFR group (mean iFR value, 0.91; n=1,012) or FFR group (mean FFR value, 0.82; n=1,007). The threshold values to perform revascularization was ≤0.89 for iFR and ≤0.80 for FFR and revascularization was deferred if iFR and FFR values were >0.89 and >0.80, respectively. [TCT 2021, Late-Breaking Clinical Science Session I]

Majority of the participants in both treatment groups underwent percutaneous coronary intervention as the primary revascularization strategy (43.8 percent [iFR] and 45.3 percent [FFR]).

The mean number of lesions evaluated was higher in the iFR group vs the FFR group (1.55 vs 1.43; p=0.002). As a lower rate of functionally significant lesions was observed with iFR compared with FFR (29.2 percent vs 36.8 percent; p<0.0001), more stents were implanted in the FFR than the iFR group (mean, 1.73 vs 1.58; p=0.048).

At 5 years of follow-up, there was no difference in the composite outcome of all-cause mortality, MI, or unplanned revascularization between the iFR and FFR groups (21.5 percent vs 19.9 percent; hazard ratio [HR] 1.09, 95 percent confidence interval, 0.90–1.33).

When assessing individual components of the composite endpoint, both iFR and FFR groups also showed comparable outcomes in terms of all-cause mortality (9.4 percent vs 7.9 percent; HR, 1.20), nonfatal MI (5.8 percent vs 5.7 percent; HR, 1.00), or unplanned revascularization at 5 years (11.6 percent vs 11.3 percent; HR, 1.02).

There was also no difference in the composite outcome across prespecified subgroups of age, gender, hypertension, hyperlipidaemia, diabetes, smoking status, or angina status.

“[Overall, this final follow-up of iFR-SWEDEHEART shows] no difference in outcome at 5 years, …  confirming the long-term safety and efficacy of revascularization guided by iFR compared with FFR,” said lead author Dr Matthias Götberg from Skåne University Hospital, Lund University in Lund, Sweden.

*iFR-SWEDEHEART: Evaluation of iFR vs FFR in stable angina or acute coronary syndrome