Right Atrial Pressure/Pulmonary Artery Wedge Pressure Ratio Correlates With Early Outcomes After Pulmonary Endarterectomy for Chronic Thromboembolic Pulmonary Hypertension

BACKGROUND AND OBJECTIVE: The expected right atrial pressure (RAP) to pulmonary arterial wedge pressure (PAWP) ratio is < 1. Inversion of this ratio (RAP ≥ PAWP) has been linked to poor outcomes in pulmonary arterial hypertension, but its relevance in chronic thromboembolic pulmonary hypertension (CTEPH) is unknown. For patients undergoing pulmonary endarterectomy (PEA), this ratio may be associated with postoperative outcomes and guide postoperative management. METHODS: We retrospectively reviewed consecutive CTEPH patients who underwent PEA at the University of California San Diego from January 2021 to December 2023. RAP/PAWP ratios ≥ 1 and < 1 were compared for postoperative outcomes. Haemodynamic data were derived from preoperative right heart catheterization. Outcomes included reperfusion pulmonary edema (RPE), ventilator days, re-intubation, ICU and hospital length of stay (LOS), and 30-day mortality. RESULTS: A total of 462 CTEPH patients met study criteria. Of these, 128 (27.7%) were in the inverse group (RAP/PAWP ≥ 1) and 334 (72.3%) in the control group (RAP/PAWP < 1). The inverse group had worse baseline functional class, cardiac index, NT-proBNP, and more haemoptysis. Postoperatively, rates of RPE (14% vs. 6%, p = 0.005) and re-intubation (5% vs. 1%, p = 0.036) were higher in the inverse group. They also required more ventilator days (2 vs. 1, p < 0.001) and had longer ICU (4 vs. 3 days, p = 0.002) and hospital LOS (13 vs. 11 days, p < 0.001). Thirty-day mortality was numerically higher in the inverse group (3% vs. 1%), though not statistically significant (p = 0.080). CONCLUSION: RAP/PAWP ratio > 1 prior to PEA surgery was associated with higher rates of early postoperative complications.