QFR Predicts the Incidence of Long-Term Adverse Events in Patients with Suspected CAD: Feasibility and Reproducibility of the Method

Abstract

AIMS: We evaluate feasibility and reproducibility of post hoc quantitative flow ratio (QFR) measurements and their prognostic predictive power during long-term follow-up. METHODS AND RESULTS: Between 2010 and 2012, 167 patients without angiographic evidence of significant stenoses were enrolled in a prospective registry. Of these patients, 96% presented 7 years follow-up data. QFR was measured post hoc by three certified investigators. QFR analysis was feasible in 71% of left anterior descending (LAD), 72% of left circumflex (LCX), and 61% of right (RCA) coronaries for a total of 350 measurements repeated in triplicate. Coefficients of variation were 2.1% for RCA and LCX, and 2.8% for the LAD (quartile coefficients of dispersion respectively 1.5, 1.4, and 1.3). QFR ≤0.80 was recorded in 25 patients (27 vessels, in 74% of the cases LAD). A total of 86 major adverse cardiovascular and cerebrovascular events were observed in 76 patients. QFR ≤0.80 in at least one of the three vessels was the strongest predictor of events (HR 3.14, 95%CI 1.78–5.54, p = 0.0001). This association was maintained in several sensitivity analyses. CONCLUSIONS: QFR reproducibility is acceptable, even when analysis is performed post hoc. A pathological QFR is not rare in patients without angiographic evidence of significant stenosis and is a predictor of incident events during long-term follow-up. Condensed Abstract: In a post hoc analysis of 167 patients without evidence of angiographic significant stenosis, the presence of QFR value ≤0.80 in at least one of the three coronary vessels showed to be the strongest predictor of major adverse cardiovascular and cerebrovascular events during long-term follow-up. QFR reproducibility have been shown to be acceptable among experienced operators.

Quantitative Flow Ratio or Angiography for the Assessment of Non-culprit Lesions in Acute Coronary Syndromes: Protocol of the Randomized Trial QUOMODO

“…In a previous study from our group, we demonstrated that QFR identifies hemodynamically relevant stenoses in about 10% of the patients who have undergone diagnostic coronary angiography and have been discharged with a diagnosis of intact coronaries. In the same study, we demonstrated that a QFR ≤ 0.80 was the strongest predictor of events (HR 3.14, 95%CI 1.78–5.54, p = 0.0001), an association which was maintained in several sensitivity analyses ( 37 ).…”

Comparison of diagnostic accuracy of immediate angiography derived residual quantitative flow ratio after bioresorbable scaffold and drug eluting stent implantation

“…FFR has many limitations in clinical practice. The use of QFR in the catheter laboratory is very feasible [17]. When computed by specialized technicians, the average QFR calculation time is only 4.36 ± 2.55 min [18].…”

Agreement of Angiography-Derived and Wire-Based Fractional Flow Reserves in Percutaneous Coronary Intervention

“…However, in a retrospective study of data collected by more than 50 centers, a weak correlation was reported between vFFR measurement and wire-based FFR measurement because of poor image quality and the difficulty tracking aortic pressure (30). The prognostic value of QFR measurements has been confirmed under various conditions (8,9,31), although the optimal cutoff values for post-PCI QFR measurements have been reported as 0.89, 0.91, and 0.80 in different studies. In the current singlecenter, retrospective study, patients with low post-PCI wirebased FFR (≤0.82) or caFFR (≤0.83) values were associated with a significantly higher risk of VOCE than those with high post-PCI FFR (>0.82) or caFFR (>0.83) values.…”