Abstract 12168: Long-Term Effects of Pulmonary Endarterectomy on Pulmonary Hemodynamics and RV Function in Chronic Thromboembolic Pulmonary Hypertension

Abstract

Background: Surgical removal of thromboembolic material by pulmonary endarterectomy (PEA) leads within months to improvement in right ventricular (RV) function in the majority of chronic thromboembolic pulmonary hypertension (CTEPH) patients. However, little is known about the long-term effects of PEA on RV function. We aimed to describe long-term changes in RV function in PEA treated CTEPH-patients. Methods: In this prospective study we included patients diagnosed with CTEPH who underwent PEA. Structured follow-up measurements were performed using right heart catheterization (RHC) and cardiac magnetic resonance (CMR) imaging before PEA and 6 and 18 months after treatment. Single beat pressure-volume loop analysis was used to determine load-independent RV contractility (Ees) and RV afterload (Ea). RV volume, mass and function were derived from CMR. Results: The study protocol was completed in 25 CTEPH-patients. PEA led to a significant decline in mean pulmonary arterial pressure (mPAP 45±11 to 24±9 mmHg; p<0.0001), pulmonary vascular resistance (PVR 561 [427-711] to 132 [112-194] dynes/s/cm 5 ; p<0.0001) and RV afterload (Ea 0.6 [0.49-0.81] to 0.2 [0.2-0.3] mmHg/ml; p<0.0001) 6 months after treatment. In addition, RV dimensions improved 6 months after PEA as demonstrated by a decrease in indexed RV end-diastolic volume (RVEDVi 91±28 to 71±13 ml/m 2 ; p=0.0009), indexed RV mass (43±15 to 27±11 g/m 2 ; p <0.0001) and increase in RV ejection fraction (RVEF 41±14 to 52±9%; p=0.0003) and Ees (0.7 [0.5-1.1] to 0.3 [0.2-0.4] mmHg/ml; p<0.0001). No further changes were seen in pulmonary hemodynamics and RV dimensions between 6 and 18 months after PEA. Conclusion: Restoration in pulmonary hemodynamics and RV dimensions occurs within 6 months after PEA. No further improvements are observed between 6 and 18 months after PEA.