Key result
Steady-state exercise in pre-capillary PH was associated with longer resistance-compliance time and greater increases in diastolic pressure gradients compared to post-capillary PH and normal controls.
Why the study?
In health, pulmonary vascular afterload stress stabilizes during steady-state exercise, but alterations of these exercise-associated stresses in pre- and post-capillary pulmonary hypertension were not well defined.
How do pulmonary vascular afterload responses to steady-state exercise differ between patients with pre-capillary PH, post-capillary PH, and normal hemodynamics?
Observational (n=76)
How do pulmonary vascular afterload responses to steady-state exercise differ between patients with pre-capillary PH, post-capillary PH, and normal hemodynamics?
Pre-capillary and post-capillary pulmonary hypertension exhibit distinct pulmonary vascular afterload responses during steady-state exercise, driven by differences in resistance-compliance time.
Differential exercise afterload patterns by PH subtype may inform testing interpretation; hypothesis-generating for RC time in PH classification.
Exercise imposes increased pulmonary vascular afterload based on rises in pulmonary artery (PA) wedge pressure, declines in PA compliance, and resistance‐compliance time. In health, afterload stress stabilizes during steady‐state exercise. Our objective was to examine alterations of these exercise‐associated stresses in states of pre‐ and post‐capillary pulmonary hypertension (PH). PA hemodynamics were evaluated at rest, 2 and 7 min of steady‐state exercise at moderate intensity in patients who exhibited Pre‐capillary ( n = 22) and post‐capillary PH ( n = 22). Patients with normal exercise hemodynamics (NOR‐HD) ( n = 32) were also studied. During exercise in all groups, PA wedge pressure increased at 2 min, with no further change at 7 min. In post‐capillary PH and NOR‐HD, increases in PA diastolic pressure and diastolic pressure gradient remained stable at 2 and 7 min of exercise, while in pre‐capillary PH, both continued to increase at 7 min. The behavior of the diastolic pressure gradient was linearly related to the duration of resistance‐compliance time at rest ( r 2 = 0.843) and exercise ( r 2 = 0.760). Exercise resistance‐compliance time was longer in pre‐capillary PH associated with larger increases in diastolic pressure gradient. Conversely, resistance‐compliance time was shortest in post‐capillary PH compared to pre‐capillary PH and NOR‐HD and associated with limited increases in exercise diastolic pressure gradient. During steady‐state, modest‐intensity exercise‐specific patterns of pulmonary vascular afterload responses were observed in pre‐ and post‐capillary PH relative to NOR‐HD. Longer resistance‐compliance time related to greater increases in PA diastolic pressure and diastolic pressure gradients in pre‐capillary PH, while shorter resistance‐compliance time appeared to limit these increases in post‐capillary PH.
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Karvasarski et al. (2023) conducted an observational in Pulmonary hypertension (n=76). Steady-state exercise vs. Rest / Normal exercise hemodynamics was evaluated on Pulmonary artery hemodynamics (PA wedge pressure, PA diastolic pressure, diastolic pressure gradient, resistance-compliance time). Steady-state exercise in pre-capillary PH was associated with longer resistance-compliance time and greater increases in diastolic pressure gradients compared to post-capillary PH and normal controls.
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