Japan Multicentre FFRangio Outcomes Registry

Background:

Visual assessment of the severity of coronary stenosis is known to have a poor diagnostic accuracy for identifying functionally significant lesion [1,2). The fractional flow reserve (FFR) is an index that quantifies the hemodynamic impact of a stenosis in an epicardial coronary artery. It is defined as the ratio of hyperemic myocardial flow in the presence of stenosis to the hyperemic flow in its absence, and is obtained by measuring the distal coronary pressure and the aortic pressure, respectively, using a pressure-measuring guidewire during maximal hyperemia [2,3]. Clinical outcome studies have shown that medical therapy should be preferred for non-hemodynamically significant lesions (FFR>0.80), and coronary revascularization should be considered in cases of significant functional stenosis (FFR≤0.80) [4-11]. Accordingly, both American and European revascularization guidelines recommend using FFR to guide coronary revascularization, especially in stable coronary artery disease patients [12,13]. In spite of these recommendations, the utilization of FFR in clinical practice remains low [14]. Recently, methods to calculate angiogram based FFR (abFFR) (without the need for pressure wires or induction of maximal coronary hyperemia) have become available. A meta-analysis of 14 studies examining various abFFR technologies ( total of 1,842 lesions), reported a sensitivity of 89%, specificity of 90%, and a C-statistic of 0.84 compared to wire based FFR (wbFFR) [15], highlighting the potential for abFFR technologies to facilitate the integration of physiologic assessment into daily cathlab practice. The FFRangioTM system (CathWorks, Kfar-Saba, Israel; Figure 1), is an angiogram-derived FFR technology that has shown excellent diagnostic performance (overall accuracy 92.6%) when compared to wire based FFR in a large pooled cohort of individual patients data from 5 individual studies (588 patients, 700 lesions) [16]. FFRangio has already received FDA 510(k) clearance for clinical use as a stand-alone technology without the need for concurrent wire based FFR measurement [17]. FFRangio has been in clinical use in Japan since 2019, but there is very limited data on the clinical outcomes of FFRangio guided treatment.

Recently, the first study examining the outcomes of FFRangio guided treatment for patients undergoing angiography for suspected coronary artery disease has reported excellent 1 year results for both FFRangio guided revascularization as well as deferral [18], but more data is needed to more appropriately assess the technology in real world patients.

The aim of this multicenter registry is to expand the evidence base on outcomes of FFRangio guided treatment for coronary artery disease, focusing on outcomes of Japanese patients.

Methods: