5.5 Impact of Pulmonary Endarterectomy on Pulmonary Arterial Wave Propagation and Reservoir Function

Recent studies have demonstrated distinctive arterial wave characteristics in patients with chronic thromboembolic pulmonary hypertension (CTEPH) 1 . Therefore, we aimed to assess the impact of pulmonary endarterectomy (PEA) on pulmonary arterial wave propagation and reservoir function in CTEPH patients. Right heart catheterization was performed using a pressure and Doppler flow sensor tipped guidewire to obtain simultaneous pressure and flow velocity measurements in the pulmonary artery in eight CTEPH patients before and 3 months after PEA. Wave intensity and reservoir-excess pressure analyses 2 were subsequently applied to the acquired data and the diastolic pressure decay time was estimated. Following PEA, mean pulmonary pressure (49 ± 10 mmHg versus 32 ± 13 mmHg), pulmonary vascular resistance (PVR) and wave speed, i.e. local arterial stiffness, significantly improved. However, there were no significant changes in arterial wave energy and wave reflection index (29.3 % [11.4–41.4 %] versus 21.2 % [16.2–25.9 %] post-PEA), even in patients with normalized pulmonary pressure. The RC-time (product of PVR and compliance) decreased post-PEA. Furthermore, the reservoir pressure related to arterial compliance, excess pressure caused by arterial waves and asymptotic pressure at which the flow would cease significantly decreased post-PEA and the changes were associated with improved right ventricular afterload, function and size. Large wave reflection persisted post-PEA indicating lack of normalization of vascular impedance mismatch. Decreased RC-time suggests structural damage to the pulmonary vasculature. Wave intensity and reservoir-excess pressure analysis may be used as an additional assessment of the hemodynamic outcomes following PEA.