Pulmonary hypertension and ventilation during exercise: Role of the pre-capillary component

Area of Science:

• Cardiology
• Pulmonology
• Exercise Physiology

Background:

• Patients with post-capillary pulmonary hypertension (PH) from left heart disease (LHD) often show excessive exercise hyperventilation and exercise oscillatory breathing (EOB).
• Pre-capillary PH is associated with even higher hyperventilation but lacks EOB.
• The impact of a pre-capillary component on exercise ventilatory response in PH with LHD is not fully understood.

Purpose of the Study:

• To investigate the influence of a pre-capillary PH component on exercise ventilatory response in patients with PH and LHD.
• To differentiate ventilatory patterns between isolated post-capillary PH (IpcPH) and combined post- and pre-capillary PH (CpcPH).

Main Methods:

• Retrospective comparison of patients with idiopathic/heritable pulmonary arterial hypertension (PAH, n=29), IpcPH (n=29), and CpcPH (n=12).
• Distinguishing IpcPH (diastolic pressure gradient [DPG] <7 mm Hg) from CpcPH (DPG ≥7 mm Hg) based on hemodynamic measurements.
• Analysis of exercise-induced hyperventilation and EOB prevalence across patient groups.

Main Results:

• Pulmonary vascular resistance (PVR) was highest in PAH, intermediate in CpcPH, and lowest in IpcPH.
• Exercise-induced hyperventilation was most pronounced in PAH, intermediate in CpcPH, and lowest in IpcPH (p < 0.001), correlating with DPG and PVR.
• EOB prevalence decreased significantly from IpcPH to CpcPH to PAH (p < 0.001).

Conclusions:

• Combined post- and pre-capillary PH (CpcPH) is associated with worse hemodynamics than IpcPH.
• CpcPH patients show distinct ventilatory alterations, including more exercise-induced hyperventilation and less EOB compared to IpcPH.
• These findings suggest the presence and extent of pulmonary vascular disease contribute to altered ventilatory control in CpcPH.