Is iFR Reliable After 5 Years? Analyzing the iFR-SWEDEHEART at 5 Years

Fractional flow reserve (FFR) proved to be very useful and safe in the FAME study, but its trade-off was using adenosine (which has a short half-life) and adverse reactions, which fortunately were rare.

¿Es confiable el iFR a 5 años? Análisis del iFR-SWEDEHEART a 5 años

Subsequently, two large studies—the iFR-SWEDEHEART and DEFINE-FLAIR—demonstrated that instantaneous wave-free ratio (iFR) offered comparable results to FFR in the short term, avoiding the use of adenosine, thus lowering costs, procedure time, and the rate of adverse reactions. It also made it somewhat easier to obtain coronary physiology data.

However, the long-term evolution of iFR has not yet been proven.

Researchers performed a 5-year analysis of the iFR-SWEDEHEART study that included 2037 patients with acute or chronic coronary syndromes. Among them, 1019 underwent iFR and 1018 underwent FFR.

There was no difference between populations. The mean age was 67 years, 75% of patients were men, 21% were diabetic, 33% had previous acute myocardial infarction, 42% had undergone a previous angioplasty, and 4% had undergone a previous myocardial revascularization surgery.

Of the subjects studied, 62% had chronic coronary syndrome, 20% had unstable angina, and the rest had non-ST-segment elevation acute myocardial infarction.

Single-vessel lesions were the most frequent type, followed by 2-vessel lesions and, to a lesser extent, 3-vessel lesions.

More lesions were analyzed in patients who underwent iFR compared with those who underwent FFR (1528 vs. 1436; p = 0.002).

After a 5-year follow-up, there were no differences in the composite endpoint of all-cause mortality, non-fatal acute myocardial infarction, or unplanned revascularization (21.5% for iFR vs. 19.9% for FFR; hazard ratio: 1.09; 95% confidence interval: 0.90-1.33). There were also no differences between strategies when analyzing all-cause mortality, non-fatal acute myocardial infarction, or unplanned revascularization.

Conclusion

In patients with acute or chronic coronary syndromes, iFR-guided revascularization offered no difference after a 5-year follow-up in mortality, myocardial infarction, or unplanned revascularization compared with the FFR-guided strategy.