Quantitative flow ratio or angiography for the assessment of non-culprit lesions in acute coronary syndromes, a randomized trial.

Background: Patients undergoing percutaneous coronary intervention for acute coronary syndromes often have multivessel disease (MVD). Quantitative flow ratio (QFR) is an angiography-based technology that may help quantify the functional significance of non-culprit lesions, with the advantage that measurements are possible also once the patient is discharged from the catheterization laboratory.

Aim: Our two-center, randomized superiority trial aimed to test whether QFR, as compared to angiography, modifies the rate of non-culprit lesion interventions (primary functional endpoint) and improves the outcomes of patients with acute coronary syndromes and MVD (primary clinical endpoint).

Methods: In total, 202 consecutive patients (64 [56-71] years of age, 160 men) with STEMI (n = 69 (34%)), NSTEMI (n = 94 (47%)), or unstable angina (n = 39 (19%)) and MVD who had undergone successful treatment of all culprit lesions were randomized 1:1 to angiography- vs. QFR-guided delayed revascularization of 246 non-culprit stenoses (1.2/patient).

Results: The proportion of patients assigned to percutaneous intervention was not different between groups (angiography group: 45 (45%) vs. QFR: 56 (55%), P = 0.125; relative risk = 0.80 (0.60-1.06)). At 12 months, a primary clinical endpoint event (composite of death, nonfatal myocardial infarction, revascularization, and significant angina) occurred in 24 patients (angiography-guided) and 23 patients (QFR-guided; P = 0.637, HR = 1.16 [0.63-2.15]). None of its components was different between groups.

Discussion: QFR guidance based on analysis of images from the primary intervention was not associated with a difference in the rate of non-culprit lesion staged revascularization nor in the 12-month incidence of clinical events in patients with acute coronary syndromes and multivessel disease.

Trial Registration Number: ClinicalTrials.gov Registry (NCT04808310).