Study question
PIONEER IV is a multicentre, open-label, 1:1 randomised non-inferiority trial in an all-comer PCI population. The interim analysis compared a QFR-guided strategy with usual care and included the first 1,270 participants: 631 assigned to QFR guidance and 639 to usual care.
Treatment framework
In the QFR arm, lesion treatment and post-PCI optimisation were guided by angiography-derived physiology. Physiological assessment and intravascular imaging in the usual-care arm were left to investigator discretion. The trial protocol used HT Supreme in both arms, followed by one month of dual-antiplatelet therapy and ticagrelor monotherapy up to one year.
Primary outcome
The 12-month patient-oriented composite endpoint was all-cause death, any stroke, any myocardial infarction, or clinically and physiologically driven revascularisation. POCE occurred in 43 of 631 participants in the QFR arm (6.9%) and 42 of 639 in the usual-care arm (6.8%). The risk difference was 0.11% (95% CI, -2.70% to 2.92%); the prespecified interim non-inferiority criterion was met (one-sided Pnon-inferiority=0.015).
Selected safety observations
The publication reported no between-group differences in all myocardial infarction, periprocedural myocardial infarction or spontaneous myocardial infarction. One acute definite stent thrombosis occurred in the usual-care arm and one late probable stent thrombosis in the QFR arm. BARC 3 or 5 bleeding was 1.8% and 1.3%, respectively (P=0.482).
Important interpretation
The authors concluded that QFR-guided PCI was non-inferior to usual care with no alarming safety signal in this interim analysis, while stating that the findings require confirmation in the full population. Because both strategies used HT Supreme, PIONEER IV should not be read as comparative evidence of one stent against another. The trial was sponsored by the University of Galway with a research grant from Sino Medical Sciences Technology Inc.