5.5 IMPACT OF PULMONARY ENDARTERECTOMY ON PULMONARY ARTERIAL WAVE PROPAGATION AND RESERVOIR FUNCTION

Abstract

Background: 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. Methods: 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 analyses2 were subsequently applied to the acquired data and the diastolic pressure decay time was estimated. Results: 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. Conclusion: 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.