Abstract 11349: Simultaneous Measurement of Lung Diffusion and Pulmonary Hemodynamics During Exercise in Heart Failure With Preserved Ejection Fraction

• Published in: Circulation (New York, N.Y.) Vol. 140; no. Suppl_1 Suppl 1; p. A11349
• Main Authors: Jorgenson, Caitlin C, Stewart, Glenn M, Borlaug, Barry A, Johnson, Bruce D
• Format: Journal Article
• Language: English
• Published: by the American College of Cardiology Foundation and the American Heart Association, Inc 19.11.2019
• ISSN: 0009-7322; 1524-4539
• DOI: 10.1161/circ.140.suppl_1.11349

IntroductionPatients with heart failure with preserved ejection fraction (HFpEF) experience exertional dyspnea that is related to elevated pulmonary arterial (PA) and venous pressures. These hemodynamic perturbations may alter ventilation-perfusion matching and the distribution of blood in the lungs, impairing gas transfer from the alveoli into the pulmonary capillaries (reducing lung diffusing capacity, DL). We hypothesized that DL for carbon monoxide (DLCO), which reflects total lung diffusion, and nitric oxide (DLNO), which reflects alveolar-capillary membrane gas conductance, would be impaired in patients with HFpEF, and would be correlated with the hemodynamic abnormalities that develop during exercise.MethodsRebreathe DLCO/NO was assessed using a mass spectrometer and nitric oxide analyzer simultaneously with invasive hemodynamic exercise testing in patients with exertional dyspnea. Systemic and PA blood samples and pressure waveforms, and breath-by-breath pulmonary gas exchange were recorded throughout rest and each stage of exercise.ResultsHFpEF patients (N=17, 12 women, 63±11 years, BMI 37±9kg/m) achieved a lower peak workload (56±27 vs. 103±37 Watts) compared to controls with non-cardiac dyspnea (N=7, 5 women, 56±7 years, BMI=30±6kg/m). DL was lower in HFpEF compared to controls at rest (DLCO, 10.3±0.8 vs. 14.4±1.3 ml/min/mmHg, p=0.01; DLNO, 28.6±2.7 vs. 41.6±4.6 ml/min/mmHg, p=0.02) and peak exercise (DLCO, 13.6±1.2 vs. 21.0±1.7 ml/min/mmHg, p<0.01; DLNO, 47.2±4.0 vs. 76.5±5.8 ml/min/mmHg, p<0.01). Impairments in DLCO during exercise were correlated with elevations in mean PA pressure (R=-0.55, p<0.01), reductions in PA compliance (R=0.56, p<0.01), and impairments in peak oxygen consumption (VO2, R=0.66, p<0.01).ConclusionsAbnormalities in pulmonary vascular hemodynamics that develop during exercise in patients with HFpEF are strongly associated with impairments in simultaneously-assessed lung diffusion and alveolar-capillary membrane conductance. These observations provide new insight into the effects of altered hemodynamics on lung function that contribute to symptoms and impairments in exercise capacity in HFpEF.