Pulmonary vascular response to exercise in heart-failure patients with pulmonary hypertension: role of a pre-capillary component

Abstract

Background: Elevated resting pulmonary arterial pressure (PAP) and a steep rise in PAP with exercise is associated with decreased exercise capacity and poor prognosis in heart-failure (HF). Aim: To determine the impact of isolated post-capillary pulmonary hypertension (IpcPH) and combined pre- and post-capillary pulmonary hypertension (CpcPH) on the pulmonary haemodynamic response to exercise in HF patients. Methods: Forty HF patients (13 no PH, 17 IpcPH, 10 CpcPH) performed exhaustive incremental exercise with simultaneous pulmonary haemodynamic monitoring. Cardiac output (Q) was determined via direct Fick and expressed relative to body surface area (cardiac index; QI). Results: At peak exercise, mean PAP (mPAP) was greater in CpcPH vs. no PH and IpcPH (55 ± 8 vs. 33 ± 9 and 46 ± 10 mmHg, P ≤ 0.029). Similarly, peak exercise mean pulmonary wedge pressure (mPWP) was greater in the CpcPH and IpcPH vs. no PH (35 ± 8 and 33 ± 8 vs. 26 ± 11 mmHg, P ≤ 0.038). The increase in mPAP, mPWP and the transpulmonary pressure gradient (TPG) from rest to peak exercise was not different between no PH, IpcPH and CpcPH. By contrast, the slope of the mPAP-QI and mPWP-QI relationship in response to exercise was greater in CpcPH vs. IpcPH vs. no PH (mPAP-QI: 6.7 ± 3.2 vs. 4.1 ± 3.9 vs. 2.6 ± 1.7mmHg/L/min/m2; mPWP-QI: 7.1 ± 3.4 vs. 5.9 ± 3.1 vs. 4.6 ± 2.0 mmHg/L/min/m2); however, only the differences between no PH and CpcPH were statistically significant. Conclusion: The development of CpcPH is associated greater pulmonary vascular pressures and a steeper pulmonary vascular pressure-to-QI relationship in response to exercise in HF patients.