Comparison of Pulmonary Artery (PA) Wave Reflections in Pulmonary Arterial Hypertension (PAH) and Pulmonary Hypertension Due to Heart Failure With Preserved Ejection Fraction (PH-HFpEF)

Pulmonary compliance (PC) for any given pulmonary vascular resistance (PVR) has been suggested to be lower in PH-HFpEF than in PAH. Hypothetically, this may lead to increased and early PA wave reflections in PH-HFpEF compared to PAH, thereby increasing right ventricular (RV) pulsatile afterload. We compared PA wave reflections in PAH and PH-HFpEF by time-domain PA waveform analysis. Right heart hemodynamics using a fluid filled system with a balloon-tipped, flow-directed catheter were obtained in 31 patients (PAH =21, PH-HFpEF=10). Of the 31 patients, we analyzed 286 and 105 PA waveforms in PAH and PH-HFpEF, respectively. Wave reflections were quantified by measuring augmentation pressure (AP difference between the systolic PAP and pressure at the inflection point), augmentation index (AI: ratio of augmentation pressure over PA pulse pressure), and inflection time (IT: time interval between systolic pressure upstroke and the inflection point) (Figure 1). Table compares the clinical and hemodynamic characteristics of the two groups. Despite similar PVR and compliance, PAH had a higher AP (7.40 ± 12.28 vs. -2.18 ± 15.34 mmHg, p<0.001), AI (0.14 ± 0.26 vs. -0.03 ± 0.35, p<0.001) and shorter IT (0.14 ± 0.07s vs. 0.20 ± 0.12s, P=<0.001) compared to PH-HFpEF. We observed increased and early-reflected waves, suggesting higher RV pulsatile afterload, in PAH compared to PH-HFpEF. Further studies are needed to determine whether this translates to an increased risk of RV failure in PAH than in PH-HFpEF.