Abstract 11981: Fractional Flow Reserve Assessment of Left Main Stenosis in the Presence of Downstream Coronary Stenoses
Background- Several studies have shown that fractional flow reserve (FFR) measurement can aid in the assessment of left main coronary stenosis. However, the impact of downstream stenosis on left main FFR assessment with the pressure wire in the nondiseased downstream vessel remains unknown. The aim of this study is to explore the effect of stenosis in a downstream epicardial artery on left main FFR assessment using an in vitro sheep model.
Methods - Variable stenoses were created in the left main coronary arteries and downstream epicardial vessels in 6 anaesthetized male sheep using balloon catheters. A total of 220 pairs of FFR assessments of the left main stenosis were obtained, before and after creation of a stenosis in a downstream epicardial vessel, by having a pressure wire in the other non-stenosed downstream vessel.
Results - The apparent left main FFR in the presence of downstream stenosis (FFRapp) was significantly higher compared to the true FFR in the absence of downstream stenosis (FFRtrue) (0.80 ± 0.05 vs. 0.76 ± 0.05, mean difference = 0.03 ± 0.03, P>0.001). The difference between FFRtrue and FFRapp correlated with composite FFR of the left main plus stenosed artery (FFRepicardial) (r = -0.31, P >0.001) indicating that this difference was greater with increasing epicardial stenosis severity (see figure below). Among measurements with FFRapp >0.80, only 9% were associated with an FFRtrue of >0.75. In all instances, the epicardial lesion was in the proximal portion of the stenosed vessel and the epicardial FFR (FFRepicardial: combined FFR of the left main and downstream stenosed vessel) was ≤0.50.
Conclusions - A clinically relevant effect on the FFR assessment of left main disease with the pressure wire in a non-stenosed downstream vessel occurs only when the stenosis in the other vessel is proximal and very severe.
- © 2012 by American Heart Association, Inc.