Abstract
Contrast-flow quantitative flow ratio (cQFR) is a new technology for quantitative evaluation of coronary stenosis using computational fluid dynamics based on angiograms. The aim of this study was to assess the sensitivity and specificity of cQFR to detect myocardial ischemia using stress magnetic resonance imaging (MRI) as a reference standard. Patients who received stress MRI and coronary angiography were selected from the hospital database. Relevant ischemia on stress MRI was defined as a perfusion deficit in ≥ 2 of 16 segments. cQFR was quantitated based on 3-dimensional quantitative coronary angiography using QAngio XA3D1.1 software by two blinded and independent investigators. A cQFR of ≤ 0.80 was considered abnormal. Among 87 patients 230 vessels met the criteria for full analysis by cQFR (88%). In vascular territories with a significant perfusion deficit, cQFR was significantly lower compared to areas with normal perfusion (0.72 (0.62–0.78) vs. 0.96 (0.89–0.99); p < 0.001). The sensitivity of cQFR in detecting significant epicardial stenoses of coronary vessels with documented ischemia in stress MRI was 81% (68–90%), the specificity was 88% (82–92%). Diameter stenoses (DS) and area stenoses (AS) in vessels with positive stress MRI were significantly higher than in vessels without ischemia (DS 59.1% (49.4–68.4%) vs. 34.8% (27.1–46.1%) p < 0.001; AS 75.6% (63.0–85.2%) vs. 45.0% (30.8–63.6%), p < 0.001). The analysis reveals a high correlation between coronary stenosis measured by cQFR and ischemic areas detected by stress MRI. The data set the stage to plan randomized studies assessing cQFR measurements with regard to clinical outcomes.
Highlights
It is state of the art to assess the hemodynamic relevance of intermediate coronary stenosis with fractional flow reserve (FFR) in the absence of evidence of ischemia [1]
The study analysed the performance of the contrast-flow quantitative flow ratio, a novel angiography-based technique to quantitate the hemodynamic relevance of coronary lesions
Diameter stenoses (DS) %diameter stenoses, AS %area stenoses, minimal lumen diameter (MLD) minimal luminal diameter correlates with significant perfusion-deficits documented by stress magnetic resonance imaging (MRI) with a sensitivity of 81%, a specificity of 88% and a diagnostic accuracy of 86%
Summary
It is state of the art to assess the hemodynamic relevance of intermediate coronary stenosis with fractional flow reserve (FFR) in the absence of evidence of ischemia [1]. The International Journal of Cardiovascular Imaging (2020) 36:1407–1416 technique, in real world practice it is used only in 6.1% of cases [3] This is most likely due to the costs of the pressure wire, the time needed for the procedure, the necessity of hyperemia for FFR evaluation with associated side effects and, most importantly, the potential complications of a coronary wire passage. All three major vessels can be analysed one after another This new technique has shown a high accuracy in determining the functional significance of coronary stenosis, using FFR as reference [7, 8], studies investigating its reliability in detecting relevant epicardial stenosis leading to ischemia in non-invasive stress testing are scarce [9, 10]. Stress MRI is one of the first guideline recommended choices approaching a patient with suspected chronic coronary syndrome [12]
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