Rationales Behind Physiology-Guided Revascularization: Diagnostic Impact of Quantitative Flow Ratio in the FAVOR III China Trial.

BACKGROUND

The optimization of a treatment plan developed on the basis of coronary angiography alone is recognized as one of the underlying rationales for the clinical benefits of physiology-guided percutaneous coronary intervention (PCI).

OBJECTIVES

The aim of this study was to investigate the diagnostic impact of quantitative flow ratio (QFR) through a post hoc analysis of the multicenter randomized FAVOR (Comparison of Quantitative Flow Ratio Guided and Angiography Guided Percutaneous Intervention in Patients With Coronary Artery Disease) III China trial.

METHODS

In FAVOR III China, operators were required to declare all target vessels intended for PCI before randomization (prerandomization declared treatment plan). After randomization, the actual treatment strategy was performed with online QFR or angiographic guidance (randomized allocation). In this study, prerandomization treatment plan and postrandomization treatment strategy were adjudicated using off-line QFR by independent core laboratory to determine physiological concordance. The primary outcome of interest for the present study was major adverse cardiac events.

RESULTS

Among 3,768 pooled patients with available off-line QFR, 2,601 (69.0%) had prerandomization physiology-concordant plans, proportions of which were comparable between the online QFR-guided and angiography-guided groups (70.9% [1,340 of 1,891] vs 67.2% [1,261 of 1,877], standardized mean difference = 0.087). Physiological concordance was reclassified in 447 (23.6%) and 87 (4.6%) patients with online QFR and angiographic guidance, respectively, and a significant between-group difference was identified in terms of achieving postrandomization physiological concordance (92.3% vs 67.2%, standardized mean difference = 0.665). A significant interaction was identified between prerandomization physiological concordance and randomized allocation for 2-year major adverse cardiac events (P for interaction = 0.002). Patients with older age, multivessel disease, left circumflex or right coronary artery involved, and lower SYNTAX (Synergy Between PCI With Taxus and Cardiac Surgery) scores were found more likely to have prerandomization physiological nonconcordance.

CONCLUSIONS

In the FAVOR III China trial, approximately 30% of patients showed discrepancies between angiography-based treatment plans and physiological ischemia. The mechanistic insight underlying the benefits of QFR-guided PCI is reclassification following online QFR guidance, which leads to a shift from initially flawed plans toward physiology-concordant decisions. (The FAVOR III China Study [FAVORIII]; NCT03656848).