QFR-Guided PCI Benefits Build Over Time: FAVOR III China

Patrice Wendling

September 19, 2022

Two-year clinical outcomes are improved with percutaneous coronary intervention (PCI) guided by quantitative flow ratio (QFR) rather than angiography, according to new results from the FAVOR III China trial.

"A QFR-guided strategy of lesion selection for PCI improved 2-year clinical outcomes compared with standard angiography guidance, with incrementally increasing benefits over time," said Lei Song, MD, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing.

The results were reported in a late-breaking session at Transcatheter Cardiovascular Therapeutics (TCT) 2022 and published simultaneously in the Journal of the American College of Cardiology.

As previously reported at TCT 2021, findings at 1-year from the sham-controlled trial showed that PCI was successful in about 95% of cases with both strategies, but QFR assessment was associated with fewer major adverse cardiac events (MACE), procedural complications, and implanted stents.

The trial enrolled patients with stable or unstable angina or a myocardial infarction (MI) at least 72 hours before screening if they had at least one coronary lesion with a diameter stenosis of 50%-90% and a reference vessel diameter of at least 2.5 mm.

In the QFR group, QFR was measured in all coronary arteries with a lesion but PCI performed only in lesions with a QFR of at least 0.80 or diameter stenosis greater than 90%.

At 2 years, the primary outcome of MACE — a composite of all-cause death, MI, or ischemia-driven revascularization — occurred in 8.5% of the QFR group and 12.5% of the angiography group (hazard ratio [HR], 0.66; P < .0001).

This was driven by fewer MIs (4.0% vs 6.8%) and ischemia-driven revascularization (4.2% vs 5.8%). The major secondary endpoint of MACE excluding periprocedural MI was also significantly lower with QFR (5.8% vs 8.8%).

All-cause death (1.1%) and cardiovascular death (0.6%) were identical in the two groups.

The QFR group had significantly lower rates of periprocedural MI (2.9% vs 4.2%), nonprocedural MI (1.1% vs 2.8%), and any revascularization (5.7% vs 7.3%). Target vessel revascularization (2.4% vs 3.5%) and stent thrombosis (0.3% vs 0.5%) trended lower.

More Pronounced Benefits

Among the 3825 randomly assigned participants, the revascularization strategy was changed after random assignment in 23.3% of patients in the QFR-guided group and 6.2% in the angiography-guided group.

This was due to treatment deferral of at least one vessel originally intended for PCI in 19.6% vs 5.2%, respectively, and unplanned PCI of at least one vessel not originally intended to be treated in 4.4% vs 1.5%, respectively.

Reductions in MACE were most pronounced in patients in whom the preplanned PCI strategy was modified by QFR and in those who had QFR-concordant treatment, Song observed via video.

The 2-year MACE rate was 8.8% with QFR-guidance and 23.5% with angiographic guidance in patients with a change in PCI strategy and 8.4% vs 11.7%, respectively, in those without a change in plans (P for interaction = .009).

MACE occurred in 8.8% of patients with pre-PCI QFR-concordant treatment vs 17.2% with nonconcordant treatment. MACE excluding periprocedural MI occurred in 6.1% vs 11.9%, respectively (P for both < .0001).

In landmark analyses, the absolute risk reductions in MACE with QFR guidance vs angiography guidance were 3.0% and 1.6% within the first year and between the first and second years (HR in each period, 0.65).

Professor Carlo Di Mario, MD, Careggi University Hospital, Florence, Italy, told theheart.org | Medscape Cardiology that the data are interesting and that QFR use is increasing in Italy but that "we need to have full agreement that this technique can replace more invasive measurements of functional severity of the lesion."

He noted that FFR and IFR are already used to overcome the limitation of angiography in detecting lesion severity but that it's unclear from the data whether QFR, the latest iteration, can really overcome this limitation. "Here, it's excluded periprocedural MI. However, most of the advantage seems to be in the first 30 days, so it's difficult for me to understand what really drives it."

Commenting for theheart.org | Medscape Cardiology, Eric A. Cohen, MD, Sunnybrook Health Sciences Centre, Toronto, Canada, said that QFR has "tremendous attraction and possibilities" but expressed concerns that it could start to displace, at least the belief, in the need for careful technique-driven angiography.

"It sort of automates the process perhaps a bit too much," Cohen said. "At least that's one of the concerns — that the operator is taken out of the equation, sort of like excessive reliance on the auto pilot in the cockpit."

Also commenting on the findings, Gary S. Mintz, MD, program director for TCT, highlighted that a "bump in events" at 1 year in the angiography arm is "typical of what we see for the self-fulfilling prophecy of the angiogram driving the events. It used to be called the oculostenotic reflex."

After the formal presentation, discussant Davide Capodanno, MD, PhD, Azienda Ospedaliero Universitaria Policlinico–Vittorio Emanuele, Catania, Italy, also noted that there was a clustering of events at 12 months and said that it suggests there was a break of blinding in the sham-controlled trial.

"I have no clear explanation for that but, obviously, if you know what's going on, you tend to revascularize and that's a probable explanation for this increase in number of events in the control group," he said.

The study was supported by grants from the Beijing Municipal Science and Technology Commission, Chinese Academy of Medical Sciences, and the National Clinical Research Center for Cardiovascular Diseases, Fuwai Hospital. Song reports having no relevant disclosures. Cohen reports grant support and research contract with Abbott Vascular and consultant fee/honoraria/speaker's bureau participation with Abbott Vascular, Medtronic, and Baylis. Mintz reports consultant fee/honoraria/speaker's bureau participation with Boston Scientific, Medtronic, and Abiomed. Capodanno reports consultant fee/honoraria/speaker's bureau participation with Amgen, Arena, Daiichi-Sankyo/Eli Lilly, Sanofi-Aventis, Terumo Medical, and Medtronic.

Transcatheter Cardiovascular Therapeutics 2022. Presented September 19, 2022.

J Am Coll Cardiol. Published September 19, 2022. Full text 

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