![]() ![]() Haemodynamics in PAH group revealed a mean pulmonary arterial pressure (PAP) of 41±5 mmHg, pulmonary vascular resistance (PVR) of 6.3±4.4 Wood units and pulmonary capillary wedge pressure (PCWP) of 8☓ mmHg. The aetiologies of PAH were idiopathic PAH (n=3), scleroderma PAH (n=2) and portopulmonary hypertension (n=1). Significance was inferred at a two-sided p<0.05. Correlation was performed using Pearson’s test. Differences between groups were compared using the Mann–Whitney U-test. Results are presented as mean± sd, unless otherwise stated. The reflection distance (L) from the measurement site was estimated from the time delay between the peaks of the forward and backward compression waves, together with knowledge of wave speed: The magnitude of wave reflection (reflection coefficient) was calculated as the ratio of the total forward compression wave intensity to the total backward compression wave intensity. Total wave energy for separated waves was calculated by integration of wave intensities over time. WIA was performed as previously described with separation of waves into forward (dI +) and backward (dI -) wave intensities: Where dP/dU is the slope of P–U loop in early systole and ρ is density of blood, assumed to be 1060 kg Wave speed (c) was derived from the P-U loop method : Intrinsic hardware processing delays (between pressure and flow signals) were corrected by shifting signals to achieve a linear pressure–flow (P–U) relationship in early systole. Signals were ensemble-averaged with timing gated to the ECG R-wave and smoothed using a Savitzky–Golay filter. #WAVE INTENSITY SOFTWARE#Pressure and flow measurements were acquired simultaneously at a sampling frequency of 1000 Hz, once stable signals were obtained.ĭata were processed offline using customised MatLab software (MathWorks, Natick, MA, USA). Following standard pulmonary haemodynamic measurements (including thermodilution cardiac output), a combined dual-tipped pressure and Doppler wire (ComboWire Volcano, Rancho Cordova, CA, USA) was positioned distal to the origin of the right or left lower lobe pulmonary artery via a 6 Fr multipurpose catheter (Mach 1 Boston Scientific, Natick, MA, USA) under angiographic guidance. Control subjects presented to the cardiac catheterisation laboratory for investigation of possible coronary artery disease. The study was approved by the institutional review board (Sydney Local Health District Ethics Review Committee (RPA Zone)) and consent was obtained from seven controls (mean± sd age 69☙ years, three females) and six patients (age 56☑3 years, four females) with pulmonary arterial hypertension (PAH). As WIA offers a potential novel approach for the study of pulmonary haemodynamics, the present study sought to evaluate the feasibility of invasive WIA of the pulmonary circulation during right heart catheterisation (RHC). To date, WIA has not been applied to the pulmonary arterial circulation in humans. It enables quantification of wave energy, separation of waves into forward and backward components, and estimation of wave speed. Wave intensity analysis (WIA) is a recently described haemodynamic analysis methodology which enables assessment of ventriculo-arterial interactions via time-domain analysis of pressure and flow waveforms. ![]()
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