Macitentan for the treatment of inoperable chronic thromboembolic pulmonary hypertension (MERIT-1): results from the multicentre, phase 2, randomised, double-blind, placebo-controlled study.

BACKGROUND: Macitentan is beneficial for long-term treatment of pulmonary arterial hypertension. The microvasculopathy of chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension are similar. METHODS: The phase 2, double-blind, randomised, placebo-controlled MERIT-1 trial assessed macitentan in 80 patients with CTEPH adjudicated as inoperable. Patients identified as WHO functional class II-IV with a pulmonary vascular resistance (PVR) of at least 400 dyn·s/cm5 and a walk distance of 150-450 m in 6 min were randomly assigned (1:1), via an interactive voice/web response system, to receive oral macitentan (10 mg once a day) or placebo. Treatment with phosphodiesterase type-5 inhibitors and oral or inhaled prostanoids was permitted for WHO functional class III/IV patients. The primary endpoint was resting PVR at week 16, expressed as percentage of PVR measured at baseline. Analyses were done in all patients who were randomly assigned to treatment; safety analyses were done in all patients who received at least one dose of the study drug. This study is registered with ClinicalTrials.gov, number NCT02021292. FINDINGS: Between April 3, 2014, and March 17, 2016, we screened 186 patients for eligibility at 48 hospitals across 20 countries. Of these, 80 patients in 36 hospitals were randomly assigned to treatment (40 patients to macitentan, 40 patients to placebo). At week 16, geometric mean PVR decreased to 71·5% of baseline in the macitentan group and to 87·6% in the placebo group (geometric means ratio 0·81, 95% CI 0·70-0·95, p=0·0098). The most common adverse events in the macitentan group were peripheral oedema (9 [23%] of 40 patients) and decreased haemoglobin (6 [15%]). INTERPRETATION: In MERIT-1, macitentan significantly improved PVR in patients with inoperable CTEPH and was well tolerated. FUNDING: Actelion Pharmaceuticals Ltd.

Does pulmonary endarterectomy improve the clinical conditions of patients with chronic thromboembolic pulmonary disease without pulmonary hypertension?

To verify whether the new hemodynamic definition of pulmonary hypertension (PH) has any implication in treatment of Chronic Thrombo-Embolic Pulmonary Disease (CTEPD) patients without PH, we retrospectively analysed the clinical and functional changes determined by pulmonary endarterectomy (PEA) in 63 CTEPD patients without PH who underwent surgery at our center, comparing those in whom the hemodynamic diagnosis of PH met recent guideline recommendations versus those in whom the diagnosis only met previous hemodynamic thresholds. The results show that the vast majority of CTEPD patients without PH operated at our center would now be defined as chronic thromboembolic pulmonary hypertension (CTEPH) patients. PEA did not result in any improvement in exercise capacity nor in right ventricular function or lung function test in patients with mean pulmonary artery pressure (mPAP) ≤ 20 mm Hg and pulmonary vascular resistance (PVR) ≤ 2 WU; on the contrary, hemodynamic parameters, exercise capacity, right ventricular function and lung function significantly improved in patients with mPAP between 21 and 24 mm Hg.

Pulmonary endarterectomy in chronic thromboembolic pulmonary hypertension: Relationship between treated branches and outcome.

BACKGROUND: In patients with chronic thromboembolic pulmonary hypertension (CTEPH) undergoing pulmonary endarterectomy (PEA) it is important to minimize residual obstructions, in order to achieve low postoperative pulmonary vascular resistances and better clinical results. The aim of the study was to test the hypothesis that the greater the number of pulmonary artery branches treated at surgery, the better the hemodynamic and clinical outcome after PEA. METHODS: In 564 consecutive CTEPH patients undergoing PEA the count of the number of treated branches was performed directly on the surgical specimens. Post-operative follow-up visits were scheduled at 3 months and 12 months after surgery including right heart catheterization and modified Bruce test. RESULTS: The population was divided into tertiles based on the number of treated branches: Group 1 (from 4 to 30 treated branches, n = 194 patients); Group 2 (from 31 to 43 treated branches, n = 190 patients); Group 3 (from 44 to 100 treated branches, n = 180 patients). At 3 and at 12 months after PEA, after adjustment for confounders, patients in the highest tertile of treated branches had significantly lower values of pulmonary vascular resistance and higher values of pulmonary arterial compliance as compared to the other two groups (p < 0.002). Hospital mortality was 3% in Group 3, 6% in Group 2 and 10% in Group 1 (overall p = 0.035). CONCLUSIONS: In CTEPH patients undergoing PEA, a higher number of treated pulmonary artery branches is associated with a better hemodynamic and a better clinical outcome at 3 months and 12 months after surgery.

A patient-specific image-based approach to estimate pulmonary artery stiffness based on vessel constitutive model.

An accurate non-invasive evaluation of the mechanical properties of the vessel wall is important for a variety of screening protocols and surgical treatments. In this work, we focused on a section of the Pulmonary Artery (PA), and developed a patient-specific approach to estimate its stiffness in terms of the Young's modulus along the circumferential direction (E). First, we developed a patient-specific semi-automatic approach to estimate its expected value and standard deviation. To this end, pressure-length curves were derived from magnetic resonance images acquired during the cardiac cycle and information on vessel pressure obtained by catheterization. Then, the estimates of E were derived through a maximum likelihood estimation approach based on a vessel constitutive law. In particular, we analyzed the entire PA boundary and an arc free from surrounding organs. Second, we applied the approach to the study of pulmonary endarterectomy (PEA) for the treatment of chronic thromboembolic pulmonary hypertension (CTEPH). We observed a decrease in the circumferential E after PEA for the whole boundary, while no clear trend was observed for the free arc. The low standard deviations associated with the estimates showed high accuracy when considering the entire boundary, while greater variability was observed for the free arc, which was however limited. Finally, reliable hysteretic behavior was obtained from the reconstructed pressure-length curves.

When you hear hoofbeats, think zebras - pulmonary veno-occlusive disease: A case report.

Pulmonary veno-occlusive disease (PVOD) is a rare disease. It may be idiopathic or associated, in particular, with connective tissue disease, or it may develop after radiation exposure; in heritable forms of PVOD, the inheritance is autosomal recessive due to the presence of homozygous or compound heterozygous pathogenic variants in the EIF2AK4 gene. We describe the case of a young man whose PVOD was initially misdiagnosed as chronic thromboembolic pulmonary hypertension despite worsening after riociguat, nonspecific computed tomography pulmonary angiogram findings, and parental consanguinity could suggest an autosomal recessive disease. The correct diagnosis and the correct treatment are crucial given the high mortality rate of this disease.

Chronic thromboembolic pulmonary hypertension risk score evaluation and validation (CTEPH SOLUTION): proposal of a study protocol aimed to realize a validated risk score for early diagnosis.

BACKGROUND: Chronic thromboembolic pulmonary hypertension (CTEPH) is the most serious long-term complication of acute pulmonary embolism (PE) though it is the only potentially reversible form of pulmonary hypertension (PH). Its incidence is mainly limited to the first 2 years following the embolic event, however it is often underdiagnosed or misdiagnosed. METHODS: This is a multicenter observational cross-sectional and prospective study. Patients with a prior diagnosis of PE will be enrolled and undergo baseline evaluation for prevalent PH detection through a clinical examination and an echocardiogram as first screening exam. All cases of intermediate-high echocardiographic probability of PH will be confirmed by right heart catheterization and then identified as CTEPH through appropriate imaging and functional examinations in order to exclude other causes of PH. A CTEPH Risk Score will be created using retrospective data from this prevalent cohort of patients and will be then validated on an incident cohort of patients with acute PE. RESULTS: One thousand retrospective and 218 prospective patients are expected to be enrolled and the study is expected to be completed by the end of 2021. Up to now 841 patients (620 retrospective and 221 prospective) have been enrolled. CONCLUSIONS: This study is the first large prospective study for the prediction of CTEPH development in patients with PE. It aims to create a comprehensive scoring tool that includes echocardiographic data which may allow early detection of CTEPH and the application of targeted follow-up screening programs in patients with PE.

Current strategies for managing chronic thromboembolic pulmonary hypertension: results of the worldwide prospective CTEPH Registry.

BACKGROUND: Pulmonary endarterectomy (PEA), pulmonary arterial hypertension (PAH) therapy and balloon pulmonary angioplasty (BPA) are currently accepted therapies for chronic thromboembolic pulmonary hypertension (CTEPH). This international CTEPH Registry identifies clinical characteristics of patients, diagnostic algorithms and treatment decisions in a global context. METHODS: 1010 newly diagnosed consecutive patients were included in the registry between February 2015 and September 2016. Diagnosis was confirmed by right heart catheterisation, ventilation-perfusion lung scan, computerised pulmonary angiography and/or invasive pulmonary angiography after at least 3 months on anticoagulation. RESULTS: Overall, 649 patients (64.3%) were considered for PEA, 193 (19.1%) for BPA, 20 (2.0%) for both PEA and BPA, and 148 (14.7%) for PAH therapy only. Reasons for PEA inoperability were technical inaccessibility (n=235), comorbidities (n=63) and patient refusal (n=44). In Europe and America and other countries (AAO), 72% of patients were deemed suitable for PEA, whereas in Japan, 70% of patients were offered BPA as first choice. Sex was evenly balanced, except in Japan where 75% of patients were female. A history of acute pulmonary embolism was reported for 65.6% of patients. At least one PAH therapy was initiated in 35.8% of patients (26.2% of PEA candidates, 54.5% of BPA candidates and 54.1% of those not eligible for either PEA or BPA). At the time of analysis, 39 patients (3.9%) had died of pulmonary hypertension-related causes (3.5% after PEA and 1.8% after BPA). CONCLUSIONS: The registry revealed noticeable differences in patient characteristics (rates of pulmonary embolism and sex) and therapeutic approaches in Japan compared with Europe and AAO.

Risk stratification in patients with residual pulmonary hypertension after pulmonary endarterectomy.

BACKGROUND: Few studies addressed the issue of risk stratification in patients with residual pulmonary hypertension (PH) after pulmonary endarterectomy (PEA). This study tested the potential added value of parameters that have not been included in existing risk models. METHODS: We evaluated 546 consecutive patients with chronic thromboembolic pulmonary hypertension who underwent PEA and were followed-up for a median period of 58 months. RESULTS: Among the 242 with residual PH, 27 died and had 127 a clinical worsening event. At univariable analysis, the parameters associated with poor survival were pulmonary vascular resistance (PVR) ≥425 dyn·s·cm-5 (p ≤ 0.001), mean pulmonary artery pressure (mPAP) ≥38 mmHg (p = 0.003) and pulmonary artery compliance (CPA) ≤1.8 ml/mmHg (p = 0.014). In the bivariable models including either PVR or mPAP as first parameter, the addition of CPA was not statistically significant. The parameters associated with poor clinical worsening were CPA ≤1.8 ml/mmHg (p < 0.001), PVR ≥425 dyn·s·cm-5 (p = 0.002), arterial oxygen tension (PaO2) ≤ 75 mmHg (p = 0.003), mPAP ≥38 mmHg (p = 0.008). In a multivariable analysis which included PVR ≥425 as the first parameter, the addition of both CPA ≤1.8 ml/mmHg and of PaO2 ≤ 75 mmHg significantly improved prognostic stratification (Harrel's C of the model = 0.64, p < 0.001). Noticeably, the lower tertile of the model's predictor index identified a subgroup of 91 patients who had an event rate numerically similar to that of patients without residual PH. CONCLUSIONS: Risk stratification in residual PH can be refined if CPA and PaO2 are considered in association with standard hemodynamic parameters.

Radiological differences between chronic thromboembolic pulmonary disease (CTEPD) and chronic thromboembolic pulmonary hypertension (CTEPH).

OBJECTIVES: The aim of this study was to describe the radiological features of chronic thromboembolic pulmonary disease (CTEPD), not yet systematically described in the literature. Furthermore, we compared vascular scores between CTEPD and chronic thromboembolic pulmonary hypertension (CTEPH) patients, trying to explain why pulmonary hypertension does not develop at rest in CTEPD patients. METHODS: Eighty-five patients (40 CTEPD, 45 CTEPH) referred to our centre for pulmonary endarterectomy underwent dual-energy computed tomography pulmonary angiography (DE-CTPA) with iodine perfusion maps; other 6 CTEPD patients underwent single-source CTPA. CT scans were reviewed independently by an experienced cardiothoracic radiologist and a radiology resident to evaluate scores of vascular obstruction, hypoperfusion and mosaic attenuation, signs of pulmonary hypertension and other CT features typical of CTEPH. RESULTS: Vascular obstruction burden was similar in the two groups (p = 0.073), but CTEPD patients have a smaller extension of perfusion defects in the iodine map (p = 0.009) and a smaller number of these patients had mosaic attenuation (p < 0.001) than CTEPH patients, suggesting the absence of microvascular disease. Furthermore, as expected, the two groups were significantly different considering the indirect signs of pulmonary hypertension (p < 0.001). CONCLUSIONS: CTEPD and CTEPH patients have significantly different radiological characteristics, in terms of signs of pulmonary hypertension, mosaic attenuation and iodine map perfusion extension. Importantly, our results suggest that the absence of peripheral microvascular disease, even in presence of an important thrombotic burden, might be the reason for the absence of pulmonary hypertension in CTEPD. KEY POINTS: • CTEPD and CTEPH patients have significantly different radiological characteristics. • The absence of peripheral microvascular disease might be the reason for the absence of pulmonary hypertension in CTEPD.

Interventional and pharmacological management of chronic thromboembolic pulmonary hypertension.

Chronic thromboembolic pulmonary hypertension (CTEPH) is caused by obstruction of the pulmonary vasculature, leading to increased pulmonary vascular resistance and ultimately right ventricular failure, the leading cause of death in non-operated patients. This article reviews the current management of CTEPH. The standard of care in CTEPH is pulmonary endarterectomy (PEA). However, up to 40% of patients with CTEPH are ineligible for PEA, and up to 51% develop persistent/recurrent PH after PEA. Riociguat is currently the only medical therapy licensed for treatment of inoperable or persistent/recurrent CTEPH after PEA based on the results of the Phase III CHEST-1 study. Studies of balloon pulmonary angioplasty (BPA) have shown benefits in patients with inoperable or persistent/recurrent CTEPH after PEA; however, data are lacking from large, prospective, controlled studies. Studies of macitentan in patients with inoperable CTEPH and treprostinil in patients with inoperable or persistent/recurrent CTEPH showed positive results. Combination therapy is under evaluation in CTEPH, and long-term data are not available. In the future, CTEPH may be managed by PEA, medical therapy or BPA - alone or in combination, according to individual patient needs. Patients should be referred to experienced centers capable of assessing and delivering all options.

ERS statement on chronic thromboembolic pulmonary hypertension.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare complication of acute pulmonary embolism, either symptomatic or not. The occlusion of proximal pulmonary arteries by fibrotic intravascular material, in combination with a secondary microvasculopathy of vessels <500 µm, leads to increased pulmonary vascular resistance and progressive right heart failure. The mechanism responsible for the transformation of red clots into fibrotic material remnants has not yet been elucidated. In patients with pulmonary hypertension, the diagnosis is suspected when a ventilation/perfusion lung scan shows mismatched perfusion defects, and confirmed by right heart catheterisation and vascular imaging. Today, in addition to lifelong anticoagulation, treatment modalities include surgery, angioplasty and medical treatment according to the localisation and characteristics of the lesions.This statement outlines a review of the literature and current practice concerning diagnosis and management of CTEPH. It covers the definitions, diagnosis, epidemiology, follow-up after acute pulmonary embolism, pathophysiology, treatment by pulmonary endarterectomy, balloon pulmonary angioplasty, drugs and their combination, rehabilitation and new lines of research in CTEPH.It represents the first collaboration of the European Respiratory Society, the International CTEPH Association and the European Reference Network-Lung in the pulmonary hypertension domain. The statement summarises current knowledge, but does not make formal recommendations for clinical practice.

Pulmonary endarterectomy in the octogenarian population: safety and outcomes.

AIMS: Aim of the study was to verify the feasibility, safety and efficacy of pulmonary endarterectomy (PEA) in octogenarian patients with chronic thromboembolic pulmonary hypertension. METHODS: We retrospectively analyzed 635 chronic thromboembolic pulmonary hypertension patients who underwent PEA at our center and were followed-up for at least 1 year. The end-points of the study were in-hospital mortality, hemodynamic results at 1 year and long-term survival. RESULTS: In-hospital mortality was 4, 10 and 17%, respectively, for 259 patients under the age of 60 years, 352 aged between 60 and 79 years and 24 octogenarians (P = 0.006 octogenarians vs. <60 years). At multivariable analysis, age and pulmonary vascular resistances were independent risk factors for mortality (P = 0.021 and P < 0.001, respectively). At 1 year, the improvement in cardiac index was lower and the distance walked in 6 min was poorer for octogenarians than for the other two groups (both P = 0.001). Survival after hospital discharge was similar over a median follow-up period of 59 months (P = 0.113). Although in-hospital mortality and long-term survival are similar in octogenarians as compared with patients aged between 60 and 79, the improvement in cardiac index and in functional capacity at 1 year are lower in this very elderly population. CONCLUSION: Age over 80 years should not be a contraindication to PEA surgery in selected patients operated on in referral centers.

Acute massive pulmonary embolism during patient repositioning following excision of a thymic carcinoma in a patient affected by cryoglobulinemia.

Acute pulmonary embolism (APE) is a well-described complication following surgical procedures. The incidence of such a complication can be related to the presence of a peculiar patient's condition. Cryoglobulinemia, which consists in the presence of one or more immunoglobulins in the serum that precipitate at temperatures below 37°C and redissolve on warming, seems to increase the risk of thrombotic events. Treatment options of APE, according to clinical severity, include systemic thrombolysis, surgical embolectomy, and systemic anticoagulation. Thrombolysis is considered the first-line treatment, whereas surgery is reserved in case of extremely-compromised hemodynamic conditions related to massive central embolism, and in case of contraindication to thrombolysis. Here, we report a case of acute massive pulmonary embolism occurring at the end of a surgical procedure for a thymic carcinoma resection, in a patient with cryoglobulinemia, which required an emergent surgical pulmonary embolectomy.

Long-Term Effects of the Replacement of Calcineurin Inhibitors With Everolimus and Mycophenolate in Patients With Calcineurin Inhibitor-Related Nephrotoxicity.

BACKGROUND: There is little evidence on the long-term effects of calcineurin inhibitor (CNI) withdrawal and substitution with everolimus and mycophenolate mofetil in maintenance therapy of patients who have received heart transplants and have concurrent CNI nephrotoxicity. Aims of this study were to evaluate the progression of renal dysfunction after discontinuation of CNIs and to monitor for major adverse events after therapy change. METHODS: Data from 41 patients who underwent heart transplant and have different degrees of renal dysfunction (estimated glomerular filtration rate [eGFR] <60 mL/min/1.73 m2), without evidence of proteinuria, and in whom CNI therapy was replaced by everolimus, were analyzed. At the time of CNI withdrawal, clinical parameters, echocardiographic data, blood tests of renal function, and monitoring of adverse events were recorded. The median follow-up period was 5 years ± 28 months. RESULTS: In 52% of patients, there was a clear improvement in renal function (10.5 mL/min/1.73 m2 of extra eGFR on average). The former were characterized by less advanced age and a short time from the heart transplant. The echocardiographic parameters showed a significant reduction in septum thickness (11.58 ± 2 mm vs 10.29 ± 2 mm; P = .0001) and in left ventricle posterior wall thickness (10.74 ± 1 mm vs 9.74 ± 1 mm; P = .0004). The incidence of late acute rejection and cardiac allograft vasculopathy was similar in our population compared to literature data. CONCLUSIONS: A therapeutic switch from CNIs to everolimus and mycophenolate mofetil can improve renal function in patients with CNI nephrotoxicity, especially in those with a shorter time period from transplantation, without exposing them to a higher incidence of late acute rejection and cardiac allograft vasculopathy.

Persistent exercise limitation after successful pulmonary endoarterectomy: frequency and determinants.

BACKGROUND: After successful pulmonary endoarterectomy (PEA), patients may still suffer from exercise limitation, despite normal pulmonary vascular resistance. We sought to assess the proportion of these patients after the extension of PEA to frail patients, and the determinants of exercise limitation. METHODS: Out of 553 patients treated with PEA from 2008 to 2016 at our institution, a cohort of 261 patients was followed up at 12 months. They underwent clinical, haemodynamic, echocardiographic, respiratory function tests and treadmill exercise testing. A reduced exercise capacity was defined as Bruce test distance < 400 m. RESULTS: Eighty patients did not had exercise testing because of inability to walk on treadmill and/or ECG abnormalities Exercise limitation 12 months after PEA was present in 74/181 patients (41, 95%CI 34 to 48%). The presence of COPD was more than double in patients with exercise limitation than in the others. Patients with persistent exercise limitation had significantly higher mPAP, PVR, HR and significantly lower RVEF, PCa, CI, VC, TLC, FEV1, FEV1/VC, DLCO, HbSaO2 than patients without. The multivariable model shows that PCa at rest and TAPSE are important predictors of exercise capacity. Age, COPD, respiratory function parameters and unilateral surgery were also retained. CONCLUSIONS: After successful PEA, most of the patients recovered good exercise tolerance. However, about 40% continues to suffer from limitation to a moderate intensity exercise. Besides parameters of right ventricular function, useful information are provided by respiratory function parameters and COPD diagnosis. This could be useful to better address the appropriate therapeutic approach.

Exercise Training After Pulmonary Endarterectomy for Patients with Chronic Thromboembolic Pulmonary Hypertension.

BACKGROUND: After undergoing a procedure of pulmonary endarterectomy (PEA), patients with chronic thromboembolic pulmonary hypertension (CTEPH) may still experience reduced exercise capacity. Data on effects of exercise training in these patients are scant. OBJECTIVES: To evaluate the effectiveness of exercise training after PEA for CTEPH and if the presence of "residual pulmonary hypertension" may affect the outcome. METHODS: Retrospective data analysis of CTEPH patients undergoing inpatient exercise training after PEA. According to predefined criteria, patients were divided into those with (group 1) and without (group 2) a "good" post-surgery hemodynamic response. Assessments of the 6-min walking distance test (6-min walking distance test [6 MWT]: primary outcome) were performed before and after surgery (before training), after training and at 3-month follow-up. Hemodynamic and lung function data were also analyzed. RESULTS: Data of 84 and 26 patients of groups 1 and 2, respectively, were analyzed. After surgery patients showed a reduction in 6 MWT, which significantly reversed after training and further improved at 3 months (p = 0.0001), without any significant difference between groups. The percentage of patients reaching the minimal clinically important difference in 6 MWT was similar between groups. The sig-nificant (p = 0.0001) post-surgery improvement in hemodynamics was maintained at 3 months without any significant difference between groups. New York Heart Association functional class improved in parallel to the hemodynamic improvement. CONCLUSIONS: Exercise training in patients with CTEPH after PEA, an inpatient exercise training program, improves exercise capacity for up to 3 months, independently of the post-surgery hemodynamic response.

Surgical Treatment for Pulmonary Embolization of a Right Atrial Myxoma.

We report the case of a woman with pulmonary embolism due to a cardiac mass. Echocardiography, computed tomography scan, and cardiac magnetic resonance raised the suspicion of right atrial myxoma and confirmed the presence of pulmonary embolism. The patient was sent to the University of Pavia School of Medicine, where the atrial myxoma was excised, and, using interrupted periods of circulatory arrest, extraction of the myxoma emboli from the pulmonary arteries was performed. No adjuvant chemotherapy was required as surgical treatment is an effective therapy in cases of pulmonary embolism of a benign neoplastic mass.

High preoperative plasma endothelin-1 levels are associated with increased acute kidney injury risk after pulmonary endarterectomy.

OBJECTIVES: The only curative treatment for chronic thromboembolic pulmonary hypertension (CTEPH) is pulmonary endarterectomy (PEA). PEA requires cardiopulmonary bypass (CPB) which is associated with a high acute kidney injury (AKI) risk. Circulating endothelin-1 (ET-1) levels are elevated in CTEPH, and ET-1 plays a pivotal role in AKI. Because AKI is burdened by high morbidity and mortality, we aimed to evaluate the association between preoperative ET-1 and the risk to develop AKI in CTEPH individuals who undergo PEA. We also evaluated the association of AKI and ET-1 with kidney function and mortality at 1 year after PEA. METHODS: In 385 consecutive patients diagnosed with CTEPH who underwent PEA at the Foundation IRCC Policlinico San Matteo (Pavia, Italy) from January 2009 to April 2015, we assessed preoperative circulating ET-1 by ELISA and identified presence of AKI based on 2012 KDIGO criteria. RESULTS: AKI occurred in 26.5% of the 347 patients included in the analysis, and was independently associated with preoperative ET-1 (p = 0.008), body mass index (BMI) (p = 0.022), male gender (p = 0.005) and duration of CPB (p = 0.002). At 1-year post PEA, estimated glomerular filtration rate (eGFR) significantly improved in patients who did not develop AKI [ΔeGFR 5.6 ml/min/1.73 m2 (95% CI 3.6-7.6), p < 0.001] but not in those with perioperative AKI. AKI (p < 0.001), age (p < 0.001), preoperative eGFR (p < 0.001) and systemic hypertension diagnosis (p = 0.015) were independently associated with 1-year ΔeGFR. Neither perioperative AKI nor preoperative ET-1 was associated with 1-year survival. CONCLUSION: Perioperative AKI is associated with higher preoperative circulating ET-1 and it negatively influences long-term kidney function in patients with CTEPH who undergo PEA.