Functional impact of exercise pulmonary hypertension in patients with borderline resting pulmonary arterial pressure

Rudolf K F Oliveira; Mariana Faria-Urbina; Bradley A Maron; Mario Santos; Aaron B Waxman; David M Systrom

doi:10.1177/2045893217709025

Functional impact of exercise pulmonary hypertension in patients with borderline resting pulmonary arterial pressure

Pulm Circ. 2017 Jul-Sep;7(3):654-665. doi: 10.1177/2045893217709025. Epub 2017 Jun 8.

Authors

Rudolf K F Oliveira^{1

2

3}, Mariana Faria-Urbina^{1

2}, Bradley A Maron^{4

5}, Mario Santos⁶, Aaron B Waxman^{1

2}, David M Systrom^{1

2}

Affiliations

¹ 1 Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
² 2 Heart & Vascular Center, Brigham and Women's Hospital, Boston, MA, USA.
³ 3 Division of Respiratory Diseases, Department of Medicine, Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil.
⁴ 4 Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
⁵ 5 Veterans Affairs Boston Healthcare System, Boston, MA, USA.
⁶ 6 Department of Physiology and Cardiothoracic Surgery, Cardiovascular R&D Unit, Faculty of Medicine, University of Porto, Portugal.

Abstract

Borderline resting mean pulmonary arterial pressure (mPAP) is associated with adverse outcomes and affects the exercise pulmonary vascular response. However, the pathophysiological mechanisms underlying exertional intolerance in borderline mPAP remain incompletely characterized. In the current study, we sought to evaluate the prevalence and functional impact of exercise pulmonary hypertension (ePH) across a spectrum of resting mPAP's in consecutive patients with contemporary resting right heart catheterization (RHC) and invasive cardiopulmonary exercise testing. Patients with resting mPAP <25 mmHg and pulmonary arterial wedge pressure ≤15 mmHg (n = 312) were stratified by mPAP < 13, 13-16, 17-20, and 21-24 mmHg. Those with ePH (n = 35) were compared with resting precapillary pulmonary hypertension (rPH; n = 16) and to those with normal hemodynamics (non-PH; n = 224). ePH prevalence was 6%, 8%, and 27% for resting mPAP 13-16, 17-20, and 21-24 mmHg, respectively. Within each of these resting mPAP epochs, ePH negatively impacted exercise capacity compared with non-PH (peak oxygen uptake 70 ± 16% versus 92 ± 19% predicted, P < 0.01; 72 ± 13% versus 86 ± 17% predicted, P < 0.05; and 64 ± 15% versus 82 ± 19% predicted, P < 0.001, respectively). Overall, ePH and rPH had similar functional limitation (peak oxygen uptake 67 ± 15% versus 68 ± 17% predicted, P > 0.05) and similar underlying mechanisms of exercise intolerance compared with non-PH (peak oxygen delivery 1868 ± 599 mL/min versus 1756 ± 720 mL/min versus 2482 ± 875 mL/min, respectively; P < 0.05), associated with chronotropic incompetence, increased right ventricular afterload and signs of right ventricular/pulmonary vascular uncoupling. In conclusion, ePH is most frequently found in borderline mPAP, reducing exercise capacity in a manner similar to rPH. When borderline mPAP is identified at RHC, evaluation of the pulmonary circulation under the stress of exercise is warranted.

Keywords: exercise; oxygen delivery; oxygen uptake; pathophysiology; pulmonary hypertension.