Endarterectomy in CTEPH: hemodynamic improvement and RV-PA coupling

Abstract Introduction Pulmonary artery endarterectomy (PAE) remains the gold standard in treating chronic thromboembolic pulmonary hypertension (CTEPH). Reducing the thrombotic burden and mechanical obstruction of the pulmonary artery (PA) leads to significant hemodynamic improvement, allowing for favorable right ventricular (RV) remodeling. Methods Single center retrospective study, including 30 pts submitted to PEA over a 7-year period. Hemodynamic assessment was performed by right heart catheterization (RHC) before PEA, immediately after and at 6-month follow-up (FUP). Echocardiographic assessment of RV function was acquired at baseline and 6m FUP. Mean absolute differences were calculated before and after PEA. Differences between groups were assessed with ANOVA analysis and ROC curve analysis allowed us to define a cut-off point in mPAP reduction to predict favorable RV remodeling. Results We included 30 pts with a mean age of 57,9 ± 13 years old and slight predominance of female sex (57%). Regarding risk assessment with the 4 strata tool at baseline, 23% of pts were high risk, 20% intermediate high, 27% intermediate low and 6% at low risk. Pulmonary hemodynamics improved immediately after PEA, as indicated by a mean reduction of 28,3 ±17 mmHg in mPAP; 44,4±27,6mmHg in sPAP; 8±3,4 Wu in PVR and an increase in CO of 0,5±1 l/min. This improvement was sustained at 6-m post PEA assessment, with a mean reduction of 31,5 ±26,7 mmHg in mPAP; 48,3±41,2mmHg in sPAP; 6,3±6,2Wu in PVR and a 0,5±1 l/min increase in CO. Regarding RV remodeling at 6m post PEA, an increase of 0.15±0.2mm/mmHg in TAPSE/PSAP ratio and 3±2,8cm/s in Tricuspid S’ were recorded. RV/PA uncoupling, defined as TAPSE/PSAP <0,31 mm/mmHg, was evident in 73% of pts at baseline, 25% of which recovered at 6m follow-up. There were no significant differences between groups, according to the 4 strata risk assessment at baseline, regarding pulmonary hemodynamics and RV remodeling. Through ROC curve analysis, we were able to define a cut-off point of 37mmHg in immediate mPAP post-op reduction to predict RV-RA coupling normalization at 6-m FUP (sensitivity 70%, specificity 89%). Conclusions PEA remains a cornerstone of CTEPH treatment. It’s impact on improving pulmonary hemodynamics is immediate and maintained at 6-month FUP. This improvement may be expected regardless of risk assessment at baseline. Reducing RV afterload allows favorable remodeling and an immediate post operative reduction of mPAP > 37mmHg may predict normalization of RV-PA coupling.