Left Ventricular Filling Pressure Estimation at Rest and During Exercise in Patients With Severe Aortic Valve Stenosis: Comparison of Echocardiographic and Invasive Measurements

Background: The Doppler index of left ventricular (LV) filling (E/e′) is recognized as a noninvasive measure for LV filling pressure at rest but has also been suggested as a reliable measure of exercise-induced changes. The aim of this study was to investigate changes in LV filling pressure, measured invasively as pulmonary capillary wedge pressure (PCWP), at rest and during exercise to describe the relation with E/e′ in patients with severe aortic stenosis. Methods: Twenty-eight patients with an aortic valve areas < 1 cm² performed a multistage supine bicycle exercise test until exhaustion. PCWP, E/e′_septal, and E/e′_lateral were determined simultaneously by echocardiography at rest and at maximal tolerated workload. Results: PCWP increased significantly from 18 ± 8 mm Hg at rest to 39 ± 10 mm Hg at peak exercise (P < .0001). E, e′_septal, and e′_lateral increased with exercise, whereas E/e′_septal remained unchanged (19 ± 6 vs 19 ± 6; P = NS), and only minimal changes were observed in E/e′_lateral (14 ± 4 vs 15 ± 4; P = .05). E/e′_septal and E/e′_lateral were significantly correlated with PCWP at rest (r = 0.72, P < .0001, and r = 0.67, P < .0001, respectively) as well as at peak exercise (r = 0.66, P = .0003, and r = 0.47, P = .02, respectively), with nearly similar slopes of the linear regression lines. The intercepts, however, increased by 18 mm Hg (P = .01) and by 19 mm Hg (P = .01) at peak exercise, respectively. Changes in E/e′_septal and E/e′_lateral were not related to changes in PCWP with exercise (P = NS). Instead, the ratio of E velocity during exercise to e′_septal at rest (E_exercise/e′_{septal, rest}) was correlated with PCWP during exercise (r = 0.61, P = .001), and furthermore, E_exercise - E_rest/e′_{septal, rest} was related to changes in PCWP (r = 0.45, P = .02). The results for the lateral side were r = 0.50 (P = .01) and r = 0.44 (P = .03), respectively. Conclusions: E/e′ is well correlated with PCWP at rest. However, E/e′ cannot be used to detect exercise-induced changes in PCWP in patients with severe aortic stenosis. Using the ratio of E during exercise to e′ at rest may result in a better estimate of the increase in PCWP during exercise.