Chronic thromboembolic pulmonary hypertension (CTEPH) is considered as a rare but severe complication after acute pulmonary embolism (PE) and is potentially curable by pulmonary endarterectomy (PEA). We aimed to evaluate, over an 11-year period, time trends of in-hospital outcomes of PEA in CTEPH patients and to investigate predictors of the in-hospital course. We analyzed data on the characteristics, comorbidities, treatments and in-hospital outcomes for all CTEPH patients treated with PEA in the German nationwide inpatient sample between 2006 and 2016. Overall, 1,398 inpatients were included. Annual number of PEA increased from 67 in 2006 to 194 in 2016 (P<0.001), in parallel with a significant decrease of in-hospital mortality (10.9% in 2008 to 1.5% in 2016; P<0.001). Patientsâ characteristics shifted slightly towards older age and higher prevalence of chronic renal insufficiency and obesity over time, whereas duration of hospital stay decreased over time. Independent predictors of in-hospital mortality were age (OR 1.03 [95%CI 1.01-1.05]; P=0.001), right heart failure (2.55 [1.37-4.76]; P=0.003), in-hospital complications such as ischemic stroke (6.87 [1.06-44.70]; P=0.044) and bleeding events like hemopneumothorax (24.93 [6.18-100.57]; P<0.001). Annual PEA volumes per center below 10 annual procedures were associated with higher rates of adverse in-hospital outcomes. Annual numbers of CTEPH patients treated with PEA increased markedly in Germany between 2006 and 2016, in parallel with a decrease of in-hospital mortality. Our findings suggest that perioperative management of PEA, institutional experience and patient-selection are crucial and have improved over time.