Fractional Flow Reserve in End-Stage Liver Disease

Abstract

Fractional flow reserve (FFR) determines the functional significance of epicardial stenoses assuming negligible venous pressure (P_v) and microvascular resistance. However, these assumptions may be invalid in end-stage liver disease (ESLD) because of fluctuating P_v and vasodilation. Accordingly, all patients with ESLD who underwent right-sided cardiac catheterization and coronary angiography with FFR as part of their orthotopic liver transplantation evaluation between 2013 and 2018 were included in the present study. Resting mean distal coronary pressure (P_d)/mean aortic pressure (P_a), FFR, and P_v were measured. FFR accounting for P_v (FFR - P_v) was defined as (P_d - P_v)/(P_a - P_v). The hyperemic effect of adenosine was defined as resting P_d/P_a - FFR. The primary outcome was all-cause mortality at 1 year. In 42 patients with ESLD, 49 stenoses were interrogated by FFR (90% were <70% diameter stenosis). Overall, the median model for ESLD score was 16.5 (10.8 to 25.5), FFR was 0.87 (0.81 to 0.94), P_v was 8 mm Hg (4 to 14), FFR-P_v was 0.86 (0.80 to 0.94), and hyperemic effect of adenosine was 0.06 (0.02 to 0.08). FFR-P_v led to the reclassification of 1 stenosis as functionally significant. There was no significant correlation between the median model for ESLD score and the hyperemic effect of adenosine (R = 0.10). At 1 year, 13 patients had died (92% noncardiac in etiology), and patients with FFR ≤0.80 had significantly higher all-cause mortality (73% vs 17%, p = 0.001. In conclusion, in patients with ESLD who underwent orthotopic liver transplantation evaluation, P_v has minimal impact on FFR, and the hyperemic effect of adenosine is preserved. Furthermore, even in patients with the predominantly angiographically-intermediate disease, FFR ≤0.80 was an independent predictor of all-cause mortality.