Abstract 17025: Left Ventricular End-Diastolic Pressure Affects Measurement of Fractional Flow Reserve
INTRODUCTION. Fractional flow reserve (FFR) is conventionally measured during maximal hyperemia as distal coronary pressure (Pd) over proximal coronary pressure (Pa) and is used to identify the need for coronary revascularization. Changes in left ventricular end-diastolic pressure (LVEDP) might affect Pd more than Pa, changing measurements of FFR. The effect of changing LVEDP on FFR measurement is unknown. We hypothesized that changing LVEDP would affect measured FFR.
METHODS. LVEDP was recorded simultaneously with Pd and Pa during conventional measurement of FFR and during intravenous infusion of nitroprusside. The relationship between LVEDP and FFR was assessed using linear mixed models with a random intercept.
RESULTS. Prospectively collected data for 528 cardiac cycles from 20 coronary arteries in 17 patients were analyzed. Prior to nitroprusside the mean Pa, Pd, FFR, and LVEDP for the arteries were 73 mmHg, 51 mmHg, 0.71, and 18 mmHg, respectively. During infusion of nitroprusside the mean Pa, Pd, FFR, and LVEDP were 62 mmHg, 43 mmHg, 0.70, and 13 mmHg, respectively. FFR < 0.80 was present in 14 arteries (70%). In a multivariable model for the entire population including both LVEDP and mean aortic pressure (MAP), LVEDP was positively associated with FFR such that for every increase in LVEDP of 1 mmHg the measured FFR increased by 0.003 (beta = 0.003; P < 0.001). MAP was not associated with FFR (beta = 0.0006; P = 0.420), suggesting that nitroprusside’s effect on MAP did not change FFR.
CONCLUSIONS. In this population of coronary arteries with mean FFR = 0.71, LVEDP was positively associated with FFR. These findings may have implications for the use of FFR in patients with heart failure and coronary artery disease.
- © 2012 by American Heart Association, Inc.