Quantitative flow ratio (QFR) is a novel approach to derive fractional flow reserve (FFR) from coronary angiography. QFR based on 3-dimensional reconstruction of angiographic images assesses the significance of coronary artery disease (CAD) without using an invasive pressure wire. This study aimed to evaluate the diagnostic accuracy of quantitative flow ratio in myocardial ischemia of coronary artery disease.

A meta-analysis was conducted of published research articles on diagnostic accuracy of QFR between January 2016 and September 2019 in the databases of PubMed, EMBASE, Cochrane Library, China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform and China Bio-medicine Database. Statistical analysis was performed with software Meta-Disc 1.4 and Stata 12.0, and the summary receiver operating characteristic (SROC) curve was drawn to evaluate accuracy of the method.

A total of 11 articles were retreived, including 1,782 patients and 2,054 vessels. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio for quantitative flow ratio respectively, were 0.86 (95% confidence interval [CI]: 0.85-0.89), 0.89 (95%CI: 0.87–0.91), 7.51(95%CI: 6.40–8.82), 0.15 (95%CI: 0.10–0.23), 54.18 (95%CI: 34.09–86.12), and the pooled AUC was 0.9458.

Several limitations should be considered when interpreting the findings of this meta-analysis. First, despite the extensive literature search, the number of included studies was small; however, the number of patients and vessels enrolled was satisfactory, thereby decreasing type II error. Furthermore, data acquisition is not comprehensive enough because the language of the literature search was limited to Chinese and English. Despite these limitations, our study suggests with a definition of ischemia as FFR ≤ 0.8, the QFR obtains high diagnostic efficacy in myocardial ischemia of CAD. It can be used as a non-invasive novel method to screen CAD patients with myocardial ischemia.