Outcomes of quantitative flow ratio-based percutaneous coronary intervention in an all-comers study

Abstract

Background: Quantitative flow ratio (QFR) is a novel angiography-based physiological index for fast computation of fractional flow reserve without the use of a pressure wire or induction of hyperaemia.

Aims: We sought to investigate the prevalence and prognostic implications of achieving physiology-consistent percutaneous coronary intervention (PCI) according to the baseline angiographic QFR in an all-comers cohort.

Methods: QFR was retrospectively analysed from the angiograms of 1,391 patients enrolled in the randomised PANDA III trial. Patients in whom all functionally ischaemic vessels (baseline QFR ≤0.80) were treated and in whom all non-ischaemic vessels (baseline QFR >0.80) were deferred were termed as having had QFR-consistent treatment; otherwise, they were termed as having had QFR-inconsistent treatment. The major outcome was two-year major adverse cardiac events (MACE; a composite of all-cause death, all myocardial infarction (MI), or any ischaemia-driven revascularisation).

Results: Overall, 814 (58.5%) patients had QFR-consistent PCI, while 577 (41.5%) patients received QFR-inconsistent PCI. Patients with QFR-consistent versus those with QFR-inconsistent treatment had a lower risk of two-year MACE (8.4% vs 14.7%; hazard ratio [HR] 0.56, 95% confidence interval [CI]: 0.41-0.78). After adjusting for differences in baseline covariates, two-year rates of MACE remained significantly lower in the QFR-consistent group (8.8% vs 13.6%; adjusted HR 0.64, 95% CI: 0.44-0.93), due mainly to reduced ischaemia-driven revascularisation (2.9% vs 8.0%; adjusted HR 0.35, 95% CI: 0.20-0.60).

Conclusions: In this post hoc analysis of an all-comers PCI trial, approximately 60% of patients were treated in accordance with what the QFR measurement would have recommended, the achievement of which was associated with improved two-year clinical outcomes. ClinicalTrials.gov identifier: NCT02017275.

Conflict of interest statement

G.W. Stone has received speaker or other honoraria from Cook, Terumo, Qool Therapeutics and Orchestra Biomed; has served as a consultant to Valfix, TherOx, Vascular Dynamics, Robocath, HeartFlow, Gore, Ablative Solutions, Miracor, Neovasc, V-Wave, Abiomed, Ancora, MAIA Pharmaceuticals, Vectorious, Reva, Matrizyme, and Cardiomech; and has equity/options from Ancora, Qool Therapeutics, Cagent, Applied Therapeutics, Biostar family of funds, SpectraWave, Orchestra Biomed, Aria, Cardiac Success, MedFocus family of funds, and Valfix. The other authors have no conflicts of interest to declare.

Figures

Figure 1. Study flow chart.

*A hierarchical listing based on the processes for QFR assessment was used to identify the exclusion reasons per patient. DICOM: Digital Imaging and Communication in Medicine; MACE: major adverse cardiac events; MI: myocardial infarction; N: number of patients; QFR: quantitative flow ratio

Figure 2. Incidence of QFR-based physiological revascularisation.

N: number of patients; QFR: quantitative flow ratio; QFR-OT: QFR-based overtreatment; QFR-OUT: QFR-based overtreatment and undertreatment; QFR-UT: QFR-based undertreatment

Figure 3. Time-to-event curves of two-year clinical outcomes among the QFR-consistent, QFR-UT, QFR-OT, and QFR-OUT groups.

Kaplan-Meier time-to-first-event curves showing the two-year cumulative incidence of the following. A) Major adverse cardiac events (MACE). B) All-cause death. C) All myocardial infarction. D) Ischaemia-driven revascularisation. CI: confidence interval; HR: hazard ratio; MACE: major adverse cardiac events; QFR-OT: QFR-based overtreatment; QFR-OUT: QFR-based overtreatment and undertreatment; QFR: quantitative flow ratio; QFR-UT: QFR-based undertreatment

Figure 4. Time-to-event curves of two-year clinical outcomes by QFR-consistent and QFR-inconsistent groups after IPTW.

Kaplan-Meier time-to-first-event curves showing the two-year cumulative incidence of the following. A) MACE. B) All-cause death. C) Any myocardial infarction. D) Ischaemia-driven revascularisation. The numbers are presented as integers. CI: confidence interval; HR: hazard ratio; IPTW: inverse probability of treatment weighting; MACE: major adverse cardiac events; QFR: quantitative flow ratio

Central illustration. QFR-based stratification and two-year outcomes.

CI: confidence interval; HR: hazard ratio; ID: ischaemia-driven; IPTW: inverse probability of treatment weighting; MACE: major adverse cardiac events; OT: overtreatment; OUT: overtreatment and undertreatment; PMI: periprocedural myocardial infarction; QFR: quantitative flow ratio; UT: undertreatment