Exercise testing in asymptomatic or minimally symptomatic aortic regurgitation: Relationship of left ventricular ejection fraction to left ventricular filling pressure during exercise

Abstract

Exercise radionuclide angiography is being used to evaluate left ventricular function in patients with aortic regurgitation. Ejection fraction is the most common variable analyzed. To better understand the rest and exercise ejection fraction in this setting, 20 patients with asymptomatic or minimally symptomatic severe aortic regurgitation were studied. All underwent simultaneous supine exercise radionuclide angiography and pulmonary gas exchange measurement and underwent rest and exercise measurement of pulmonary artery wedge pressure (PAWP) during cardiac catheterization. Eight patients had a peak exercise PAWP < 15 mm Hg (group 1) and 12 had a peak exercise PAWP ≥ 15 mm Hg (group 2). Group 1 patients were younger and more were in New York Heart Association class I. Group 1 patients also had a higher mean rest ejection fraction (0.64 ± 0.08 vs 0.49 ± 0.01, higher exercise ejection fraction (0.63 ± 0.10 vs 0.40 ± 0.18, p < 0.01), lower end-systolic volume (38 ± 13 vs 79 ± 36 ml/m2, p < 0.01) and higher peak oxygen uptake (24.9 ± 5.1 vs 16.6 ± 4.9 ml/kg/min, p < 0.01) than group 2 patients. However, the two groups had similar cardiothoracic ratios, changes in ejection fractions with exercise, and rest and exercise regurgitant indexes. Using multiple regression analysis, the best correlate of the exercise PAWP was peak oxygen uptake (r = -0.78, p < 0.01). No other measurement added significantly to the regression. When peak oxygen uptake was excluded, rest and exercise ejection fraction also correlated significantly (r = -0.62 and r= -0.60, respectively, p < 0.01). Patients with asymptomatic or minimally symptomatic severe aortic regurgitation have a wide spectrum of cardiac performance in terms of the PAWP during exercise. The absolute rest and exercise ejection fraction and the level of exercise achieved are noninvasive variables that correlate with exercise PAWP in aortic regurgitation, but the change in ejection fraction with exercise by itself is not.