Abstract 18563: Pulmonary Artery Pressure Response Pattern in Heart Failure with Preserved Ejection Fraction
Background: Inefficient ventilation during exercise, defined by steep relationship between ventilation and carbon dioxide output (VE/VCO2) purports a poor prognosis in heart failure (HF) patients regardless of ejection fraction (EF). However the extent to which VE/VCO2 slope reflects hemodynamic impairment during exercise in HFpEF is unknown. We therefore investigated hemodynamic response patterns in relation to exercise gas exchange parameters in HFpEF compared to normal controls.
Methods/Results: We studied consecutive patients referred for cardiopulmonary exercise testing with hemodynamic monitoring who had RER >1.05 and either resting supine pulmonary capillary wedge pressure (PCWP) >15 or exercise PCWP >20 mmHg and LVEF >0.50 (HFpEF, N=54, Age 62±11, Male 54%) and normal controls (N=16, Age 47±16, Male 37%). We measured simultaneous cardiac filling pressures, VO2 and arterial and mixed venous blood gases (to determine Fick cardiac outputs [CO]) during every minute throughout incremental upright cycle ergometry CPET. HFpEF patients had higher VE/VCO2 slope than controls (36±7 vs. 31±7) and steeper, linear increments in PAP and PCWP relative to CO (3.6 and 2.7 mmHg/L min-1 compared to 1.6, and 1.1 mmHg/L min-1 respectively, all p<0.05, Figure).Upon stratification of the HFpEF patients by median VE/VCO2 (36) we found that higher VE/VCO2 was associated with steeper PAP slope (4.3 vs. 3.1 mmHg/L, p=0.02) and PCWP slope (3.6 vs. 2.5 mmHg/L, p=0.04) despite no difference between the two HFpEF sub-groups in resting upright PAP or PCWP.
Conclusions: We observed a linear increment in PAP and PCWP in HFpEF and controls during incremental cycle ergometry exercise. Ventilatory inefficiency is an easily measured, non-invasive variable that reflects impaired pressure-flow response patterns to exercise in patients with HFpEF.
- © 2012 by American Heart Association, Inc.