Modification of pulmonary endarterectomy to prevent neurologic adverse events.

PURPOSE: Neurologic adverse events (NAEs) are a major complication after pulmonary endarterectomy (PEA) performed under periods of deep hypothermic circulatory arrest (HCA) for chronic thromboembolic pulmonary hypertension. We modified the PEA strategy to prevent NAEs and evaluated the effectiveness of these modifications. METHODS: We reviewed the surgical outcomes of 87 patients divided into the following three groups based on the surgical strategy used: group S (n = 49), periods of deep HCA with alpha-stat strategy; group M1 (n = 19), deep HCA with modifications of slower cooling and rewarming rates and the pH-stat strategy for cooling: and group M2 (n = 13), multiple short periods of moderate HCA. RESULTS: PEA provided significant improvement of pulmonary hemodynamics in each group. Sixteen (29%) of the 49 group S patients suffered NAEs, associated with total circulatory arrest time (cutoff, 57 min) and Jamieson type I disease. The Group M1 and M2 patients did not suffer NAEs, although the group M1 patients had prolonged cardiopulmonary bypass (CPB) and more frequent respiratory failure. CONCLUSIONS: NAEs were common after PEA performed under periods of deep HCA. The modified surgical strategy could decrease the risk of NAEs but increase the risk of respiratory failure. Multiple short periods of moderate HCA may be useful for patients at risk of NAEs.

Altered gut microbiota and its association with inflammation in patients with chronic thromboembolic pulmonary hypertension: a single-center observational study in Japan.

BACKGROUND: The pathogenesis of chronic thromboembolic pulmonary hypertension (CTEPH) is considered to be associated with chronic inflammation; however, the underlying mechanism remains unclear. Recently, altered gut microbiota were found in patients with pulmonary arterial hypertension (PAH) and in experimental PAH models. The aim of this study was to characterize the gut microbiota in patients with CTEPH and assess the relationship between gut dysbiosis and inflammation in CTEPH. METHODS: In this observational study, fecal samples were collected from 11 patients with CTEPH and 22 healthy participants. The abundance of gut microbiota in these fecal samples was assessed using 16S ribosomal ribonucleic acid (rRNA) gene sequencing. Inflammatory cytokine and endotoxin levels were also assessed in patients with CTEPH and control participants. RESULTS: The levels of serum tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-8, and macrophage inflammatory protein (MIP)-1α were elevated in patients with CTEPH. Plasma endotoxin levels were significantly increased in patients with CTEPH (P < 0.001), and were positively correlated with TNF-α, IL-6, IL-8, and MIP-1α levels. The 16S rRNA gene sequencing and the principal coordinate analysis revealed the distinction in the gut microbiota between patients with CTEPH (P < 0.01) and control participants as well as the decreased bacterial alpha-diversity in patients with CTEPH. A random forest analysis for predicting the distinction in gut microbiota revealed an accuracy of 80.3%. CONCLUSION: The composition of the gut microbiota in patients with CTEPH was distinct from that of healthy participants, which may be associated with the elevated inflammatory cytokines and endotoxins in CTEPH.

Vascular involvement in chronic thromboembolic pulmonary hypertension is associated with spirometry obstructive impairment.

BACKGROUND: Chronic thromboembolic pulmonary hypertension (CTEPH) is a type of pulmonary hypertension caused by persistent thromboembolism of the pulmonary arteries. In clinical practice, CTEPH patients often show obstructive ventilatory impairment, even in the absence of a smoking history. Recent reports imply a tendency for CTEPH patients to have a lower FEV1.0; however, the mechanism underlying obstructive impairment remains unknown. METHODS: We retrospectively analyzed CTEPH patients who underwent a pulmonary function test and respiratory impedance test to evaluate their exertional dyspnea during admission for right heart catheterization from January 2000 to December 2019. We excluded patients with a smoking history to rule out the effect of smoking on obstructive impairment. RESULTS: A total of 135 CTEPH patients were analyzed. The median FEV1.0/FVC was 76.0%, %FEV 1.0 had a negative correlation with the mean pulmonary artery pressure and pulmonary vascular resistance and the CT Angiogram (CTA) obstruction score. A multivariate regression analysis revealed that the CTA obstruction score was an independent factor of a lower %FEV1.0. In the 54 patients who underwent pulmonary endarterectomy, %FEV1.0 was improved in some cases and was not in some. Mean PAP largely decreased after PEA in the better %FEV1.0 improved cases, suggesting that vascular involvement in CTEPH could be associated with spirometry obstructive impairment. CONCLUSION: %FEV1.0 had a significant correlation with the CTA obstruction score. Obstructive impairment might have an etiological relationship with vascular involvement. Further investigations could shed new light on the etiology of CTEPH.

Cell Tracking Suggests Pathophysiological and Therapeutic Role of Bone Marrow Cells in Sugen5416/Hypoxia Rat Model of Pulmonary Arterial Hypertension.

BACKGROUND: The mechanism of vascular remodelling in pulmonary arterial hypertension (PAH) remains unclear. Hence, defining the origin of cells constituting intractable vascular lesions in PAH is expected to facilitate therapeutic progress. Herein, we aimed to evaluate the origin of intractable vascular lesions in PAH rodent models via bone marrow (BM) and orthotopic lung transplantation (LT). METHODS: To trace BM-derived cells, we prepared chimeric rats transplanted with BM cells from green fluorescent protein (GFP) transgenic rats. Male rats were transplanted with lungs obtained from female rats and vice versa. Pulmonary hypertension was induced in the transplanted rats via Sugen5416 treatment and subsequent chronic hypoxia (Su/Hx). RESULTS: In the chimeric Su/Hx models, GFP-positive cells were observed in the pulmonary vascular area. Moreover, the right ventricular systolic pressure was significantly lower compared with wild-type Su/Hx rats without BM transplantation (P = 0.009). PAH suppression was also observed in rats that received allograft transplanted BM transplantation. In male rats that received LT and Su/Hx, BM-derived cells carrying the Y chromosome were also detected in neointimal occlusive lesions of the transplanted lungs received from female rats. CONCLUSIONS: BM-derived cells participate in pulmonary vascular remodelling in the Su/Hx rat model, whereas BM transplantation may contribute to suppression of development of PAH.

Nocturnal Hypoxemia and High Circulating TNF-α Levels in Chronic Thromboembolic Pulmonary Hypertension.

Objective Chronic thromboembolic pulmonary hypertension (CTEPH) is a form of pulmonary hypertension caused by persistent thromboemboli of the pulmonary arteries, and one of its etiological factors may be inflammation. Sleep disordered breathing (SDB) is reportedly an important complication of pulmonary hypertension. However, the association between SDB and inflammation in CTEPH has been undefined. This prospective observational study analyzed the association between the severity of SDB, pulmonary hemodynamic parameters and the systemic inflammation level in patients with CTEPH. Methods CTEPH patients admitted for a right heart catheter (RHC) examination were consecutively enrolled from November 2017 to June 2019 at the pulmonary hypertension center in Chiba University Hospital. Patients with idiopathic pulmonary arterial hypertension (IPAH) were also enrolled as a control group. All patients underwent a sleep study using a WatchPAT 200 during admission. Results The CTEPH patients showed worse nocturnal hypoxemia, oxygen desaturation index (ODI), and apnea-hypopnea index than the IPAH patients. Among these factors, only the nocturnal mean percutaneous oxygen saturation (SpO2) was negatively correlated with the pulmonary hemodynamic parameters. The circulating tumor necrosis factor-alpha (TNF-α) level was also high in the CTEPH group, and a multivariate analysis showed that the nocturnal mean SpO2 was the most important predictive factor for a high TNF-α level. Conclusion We showed that CTEPH patients had high serum TNF-α levels and that the nocturnal mean SpO2 was a predictive factor for serum TNF-α levels. Further investigations focused on nocturnal hypoxemia and the TNF-α level may provide novel insight into the etiology and new therapeutic strategies for CTEPH.

Characterization of pulmonary intimal sarcoma cells isolated from a surgical specimen: In vitro and in vivo study.

Pulmonary intimal sarcoma (PIS) constitutes a rare sarcoma originating from the intimal cells of pulmonary arteries. The pathogenesis of PIS remains to be elucidated and specific treatments have not been established; therefore, prognosis is generally poor. The purpose of our study was to isolate and characterize PIS cells from a specimen resected from a patient with PIS. The surgical specimen was minced and incubated, and spindle-shaped and small cells were successfully isolated and designated as PIS-1. PIS-1 cells at passages 8-9 were used for all in vitro and in vivo experiments. Immunocytochemistry showed that PIS-1 cells were positive for vimentin, murine double minute 2, and CD44 and negative for α-smooth muscle actin, CD31, von Willebrand factor, and desmin. PIS-1 cells exhibited the hallmarks of malignant cells including the potential for autonomous proliferation, anchorage-independent growth, invasion, genetic instability, and tumorigenicity in severe combined immunodeficiency mice. The PIS-1 cells highly expressed tyrosine kinase receptors such as platelet-derived growth factor receptor, and vascular endothelial growth factor receptor 2. Pazopanib, a multi-targeted tyrosine kinase inhibitor, suppressed the proliferation of PIS-1 cells in vitro and the growth of tumors formed from xenografted PIS-1 cells. A PIS cell line was thus successfully established. The PIS-1 cells highly expressed tyrosine kinase receptors, which may be a target for treatment of PIS.

Effectiveness of pulmonary vasodilators on pulmonary hypertension associated with POEMS syndrome.

Polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes (POEMS) syndrome is a rare plasma cell disease. Patients with POEMS syndrome are considered to be at a high risk of developing pulmonary hypertension (PH). We report a 51-year-old woman diagnosed with PH associated with POEMS syndrome. She was started on dexamethasone and thalidomide. Although, the plasma vascular endothelial growth factor (VEGF) level decreased, systolic pulmonary artery pressure (sPAP) remained high. Auto-peripheral blood stem cell transplantation improved the plasma VEGF and sPAP levels. Four years later, she presented with dyspnoea on exertion, and elevated plasma VEGF and sPAP levels. Subsequently, on administering sildenafil and macitentan, the plasma VEGF and PH levels improved. Pulmonary vasodilators can be considered when PH remains after treatment of POEMS syndrome.

Clinical characteristics and prognosis in patients with chronic thromboembolic pulmonary hypertension and a concomitant psychiatric disorder.

Chronic thromboembolic pulmonary hypertension (CTEPH) can cause right heart failure. A concomitant psychiatric disorder (PD) is thought to increase the risk of acute pulmonary thromboembolism; however, whether PDs are associated with deterioration in CTEPH pathophysiology is unclear. In this study, we evaluated the clinical characteristics and prognoses in patients with CTEPH and a co-existing PD. We retrospectively identified 229 consecutive patients (mean age = 58.7 ± 12.5 years; 160 women) with CTEPH and categorized them according to whether they had a PD (PD group; n = 22, 9.7%) or not (non-PD group; n = 207, 90.3%). We compared the clinical characteristics, respiratory function, hemodynamics, and clinical courses in the two groups. Those in the PD group had significantly lower exercise tolerance compared to the non-PD group (6-min walk test, 309.5 ± 89.5 m vs. 369.4 ± 97.9 m, P = 0.008, percent vital capacity 85.5% ± 17.3% vs. 96.0% ± 15.5%, P = 0.003) and partial pressure of oxygen (PaO2) (54.4 ± 8.6 mmHg vs. 59.3 ± 10.7 mmHg, P = 0.039). Three-year survival was significantly poorer in the PD group compared to the non-PD group (66.1% vs 89.7%, P = 0.0026, log-rank test), particularly in patients who underwent surgery (62.2% vs 89.5%, P < 0.001, log-rank test). A concomitant PD was associated with low exercise tolerance and impaired respiratory function in patients with CTEPH and predicted poor survival, especially in those who underwent a pulmonary endarterectomy.

Elevated levels of autoantibodies against EXD2 and PHAX in the sera of patients with chronic thromboembolic pulmonary hypertension.

While circulating autoantibodies have been detected in patients with several cardiovascular diseases, such studies have not been performed for chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension (PAH). Here we investigated the production of certain auto-antibodies in CTEPH patients. Initial screening was performed in 5 CTEPH patients and 5 healthy donors (HDs) using a ProtoArray Human Protein Microarray v5.1 containing 9,375 human proteins, and we selected 34 antigens recognized by IgG antibodies more strongly in the sera of CTEPH patients than in the sera of HDs. In subsequent second/third analyses, we validated the auto-antibody level using amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) in 96 CTEPH patients and 96 HDs as follows: At the second screening, we used 63 crude peptides derived from those selected 34 antigens and found that the serum levels of autoantibodies for 4 peptides seemed higher in CTEPH patients than in HDs. In third analysis, we used the purified peptides of those selected in second screening and found that serum antibodies against peptides derived from exonuclease 3'-5' domain-containing 2 (EXD2) and phosphorylated adaptor for RNA export (PHAX) were significantly higher in CTEPH patients than in HDs. The serum antibody levels to these antigens were also elevated in PAH patients. The titers against EXD2 peptide decreased after surgical treatment in CTEPH patients. These autoantibodies may be useful as biomarkers of CTEPH and PAH, and further investigations may provide novel insight into the etiology.

Use of vasodilators for the treatment of pulmonary veno-occlusive disease and pulmonary capillary hemangiomatosis: A systematic review.

BACKGROUND: There are several medications available to treat pulmonary arterial hypertension (PAH): PAH-targeted drugs. However, in patients with pulmonary veno-occlusive disease and pulmonary capillary hemangiomatosis (PVOD/PCH), rare diseases that cause pulmonary hypertension, the effectiveness and safety of vasodilators, including PAH-targeted drugs, are unclear. METHODS: We searched English-language publications listed in three electronic databases (PubMed, Cochrane Library, and the Japan Medical Abstracts Society). Reports with efficacy outcomes (survival, improvement in 6-minute walk distance, and pulmonary vascular resistance) and data on development of pulmonary edema after administration of vasodilators to patients with PVOD/PCH were selected (1966 to August 2015). RESULTS: We identified 20 reports that met our criteria. No randomized controlled or prospective controlled studies were reported. The survival time ranged from 71 minutes to 4 years or more after initiation of vasodilators. Most of the reported cases showed an improvement in the 6-minute walk distance and pulmonary vascular resistance. Pulmonary edema was reported in 15 articles, some cases of which were lethal. CONCLUSIONS: The present study demonstrates the potential efficacy and difficulties in the use of vasodilators in patients with PVOD/PCH; however, drawing a firm conclusion was difficult because of the lack of randomized controlled trials. Further research is needed to ascertain if vasodilator use is beneficial and safe in patients with PVOD/PCH.

Safety of diagnostic flexible bronchoscopy in patients with echocardiographic evidence of pulmonary hypertension.

BACKGROUND: The presence of pulmonary hypertension (PH) and treatment with anticoagulant agents could potentially increase the risk for bleeding/hemodynamic complications associated with bronchoscopic procedures. The aim of this study was to assess the safety of diagnostic flexible bronchoscopy (FB) in patients with PH. METHODS: A retrospective review of clinical records of patients with echocardiographic evidence of PH (right ventricular systolic pressure [RVSP] > 40 mm Hg) who underwent diagnostic FB between 2004 and 2016 at a single facility in Japan was conducted. Patients with no clinical evidence suggestive of PH who underwent FB during the same period were enrolled as a pairwise-matched control group; factors used in matching included age, sex, and performed procedures. RESULTS: Overall, there were 45 patients in the PH group and 90 patients in the control group. Six (13%) patients in the PH group had severe PH (RVSP > 61 mm Hg). Forceps biopsies and transbronchial needle aspirations were performed in 62% and 13% of patients, respectively, in the PH group, and 58% and 13% of patients, respectively, in the control group. The total incidence of bleeding during FB was not significantly different between the two groups (18% versus 16%; p = 0.742). Vital signs recorded 2 h after FB were also not significantly different between the two groups. There were no episodes of cardiac arrhythmias or deaths associated with the FB procedures. CONCLUSIONS: The data suggest that diagnostic FB procedures can be performed safely in patients with echocardiographic evidence of PH.

Pulmonary Hypertension Exacerbated by Nintedanib Administration for Idiopathic Pulmonary Fibrosis.

The patient was a 71-year-old man with severe idiopathic pulmonary fibrosis (IPF) and who demonstrated a slow deterioration of his respiratory condition. After nintedanib administration, his forced vital capacity and chest high-resolution computed tomography (HRCT) findings were stable, but his dyspnea on exertion were worsened. He was diagnosed with pulmonary hypertension (PH) by right heart catheterization (mean pulmonary arterial pressure: 30 mmHg). In this case, we suspected that nintedanib caused his PH, as his IPF had not progressed.

Prospective Registry of Rivaroxaban Management of Cancer-Associated Venous Throboembolism (PRIMECAST) Study.

Background: The incidence of thromboembolism in patients with cancer is approximately 11%, and the risk of thrombosis in patients with malignant tumors is 6-fold higher than that in healthy persons. Thrombosis not only disrupts the treatment of cancer but also induces deterioration of quality of life (QOL). Knowledge about thrombus treatment is limited, and evidence is scarce. Clarification of the status and safety of venous thromboembolism (VTE) treatment in patients with cancer will contribute to active intervention and improvement of prognosis and QOL. In this study, the therapeutic effects of a non-vitamin K antagonist oral anticoagulant for VTE and the prognosis of cancer after treatment will be examined to establish a therapeutic method for VTE in patients with cancer. Methods and Results: A multicenter, non-interventional, observational study will be conducted in patients with cancer who developed VTE and underwent anticoagulant therapy with rivaroxaban (group A) or warfarin (group B) for 24 weeks. The primary endpoint will be the recurrence/aggravation of symptomatic VTE or occurrence/aggravation of deep vein thrombosis. Registration of 500 patients is needed in order to calculate the 95% confidence interval of the event rate at ±1% precision. Conclusions: The investigation period will run from January 2019 to December 2023 with ongoing selection of patients. Trial registration: no. 5-18-32 (approved 1 August 2018).

Features of radiological and physiological findings in pulmonary capillary hemangiomatosis: an updated pooled analysis of confirmed diagnostic cases.

Pulmonary capillary hemangiomatosis (PCH) is a very rare and refractory disease characterized by capillary angioproliferation. The updated classification of pulmonary hypertension categorizes PCH into a subgroup of pulmonary arterial hypertension (PAH) alongside pulmonary veno-occlusive disease (PVOD). However, the definitive diagnosis of PCH only with noninvasive tools remains difficult. The aim of this study was to elucidate the radiological and physiological characteristics of PCH. We searched for cases of pathologically confirmed PCH in the English literature published between 2000 and 2018. We identified 26 cases among 39 studies. Then, we extracted and evaluated the relevant clinical information in all cases with available data. On chest computed tomography (CT), ground-glass opacities (GGOs) were observed in 92% of the cases, in which poorly defined nodular pattern was the most common (88%). GGOs in a bat-wing distribution were observed in one case. Septal lines and lymph node enlargement were observed less frequently (each 19%, 12%). Seven cases (27%) had overlapping abnormalities. Diffusing capacity of the lung for carbon monoxide (DLCO) was remarkably decreased. Alveolar hemorrhage by histological findings or bronchoalveolar lavage (BAL) was observed in seven cases. The present study showed that the most characteristic findings of CT in PCH was centrilobular GGOs with a poorly defined nodular pattern, and septal lines and lymph node enlargement were seen less frequently. Alveolar hemorrhage detected by BAL and decreased DLCO may also be helpful to recognize the possibility of PCH like PVOD.

Endothelial cells from pulmonary endarterectomy specimens possess a high angiogenic potential and express high levels of hepatocyte growth factor.

BACKGROUND: Impaired angiogenesis is assumed to be an important factor in the development of chronic thromboembolic pulmonary hypertension (CTEPH). However, the role of endothelial cells (ECs) in CTEPH remains unclear. The aim of this study was to investigate the angiogenic potential of ECs from pulmonary endarterectomy (PEA) specimens. METHODS: We isolated ECs from PEA specimens (CTEPH-ECs) and control EC lines from the intact pulmonary arteries of patients with peripheral lung cancers, using a MACS system. These cells were analyzed in vitro including PCR-array analysis, and the PEA specimens were analyzed with immunohistochemistry. Additionally, the serum HGF levels were determined in CTEPH patients. RESULTS: A three-dimensional culture assay revealed that CTEPH-ECs were highly angiogenic. An angiogenesis-focused gene PCR array revealed a high expression of hepatocyte growth factor (HGF) in CTEPH-ECs. The high expression of HGF was also confirmed in the supernatant extracted from PEA specimens. The immunohistochemical analysis showed expression of HGF on the surface of the thrombus vessels. The serum HGF levels in CTEPH patients were higher than those in pulmonary thromboembolism survivors. CONCLUSION: Our study suggests that there are ECs with pro-angiogenetic character and high expression of HGF in PEA specimens. It remains unknown how these results are attributable to the etiology. However, further investigation focused on the HGF pathway may provide novel diagnostic and therapeutic tools for patients with CTEPH.

Cytomegalovirus Pneumonia with Progressive Lung Volume Loss.

BACKGROUND Cytomegalovirus (CMV) pneumonia is common in immunocompromised patients with hematological malignancies. Although the spectrum of illness caused by CMV is well-documented in immunocompromised patients, the clinical course and evolution of lung changes after initiation of antiviral therapy remain unclear. CASE REPORT We present the cases of 3 patients with leukemia who developed CMV pneumonia following cord blood transplantation and who presented with distinctive features on chest computed tomography (CT). In all patients, chest CT showed central peribronchial changes with severe lung volume loss. Furthermore, the patients were refractory to high-dose steroids, and the lung volume loss rapidly progressed, leading to death from respiratory failure. CONCLUSIONS We observed central peribronchial changes with severe lung volume loss after the acute phase in 3 cases of CMV pneumonia. While our diagnosis was made on the basis of exclusion, it is important to bear in mind that lung involvement in CMV pneumonia may be refractory to various treatment modalities and can lead to a fatal clinical course.

Aspergillus Sternomyelitis Developed from Chronic Pulmonary Aspergillosis as a Late Complication to Lobectomy for Lung Cancer.

Progressive fibrobullous changes in the residual lobes are sometimes observed after lobectomy. Aspergillus osteomyelitis is an uncommon infection that rarely occurs sternally. A 70-year-old man who had undergone lobectomy 12 years earlier was admitted to our hospital for chest pain. He was diagnosed with Aspergillus sternomyelitis based on sternal bone culture after an ultrasound-guided percutaneous needle biopsy. The fibrosis and right residual lung apex volume loss had gradually progressed over 12 years, and therefore, chronic pulmonary aspergillosis (CPA) with direct invasion sternal from the CPA was considered. Aspergillus sternomyelitis can develop from CPA as a late complication of lobectomy.

Evaluation of the clinical characteristics of everolimus-induced lung injury and determination of associated risk factors.

BACKGROUND: Everolimus (ERL), a mammalian target of rapamycin (mTOR) inhibitor, has been used for the management of several advanced cancers. ERL frequently causes lung injury, although the clinical and radiographic features have not been clarified. The aim of this study was to assess the clinical features of ERL-induced lung injury and determine the associated risk factors. METHODS: This single-center, retrospective study included 45 patients (29 men, 16 women; age, 12-78 years) who had received ERL at our hospital between August 2010 and March 2016. Drug-induced lung injury (DILI) was diagnosed using the Japanese Respiratory Society criteria. We obtained information regarding the clinical course, symptoms, clinical findings, blood test findings, and chest computed tomography findings from the patients' medical records. Risk factors for DILI onset were investigated using the Wilcoxon rank sum test. RESULTS: Fifteen patients (33%) were diagnosed with DILI. The median time from ERL administration to DILI onset was 64 days. High Serum Krebs von den Lungen-6 (KL-6) levels and a low estimated glomerular filtration rate (eGFR) before ERL administration were found to be significant risk factors for DILI. KL-6 and lactate dehydrogenase (LDH) were significantly elevated at the onset of DILI. All 15 patients recovered; 11 were without steroids. CONCLUSIONS: Our results suggest that patients with high KL-6 levels and a low eGFR at baseline are at increased risk of ERL-induced lung injury. In addition, KL-6 and LDH may be useful biomarkers of ERL-induced lung injury.

Balloon Pulmonary Angioplasty for Chronic Thromboembolic Pulmonary Hypertension: Results of a Multicenter Registry.

BACKGROUND: Balloon pulmonary angioplasty (BPA) is an alternative therapy for patients with chronic thromboembolic pulmonary hypertension who are ineligible for pulmonary endarterectomy-the standard therapy. Currently, most reported results of BPA are from relatively small cohorts treated at single centers. The present study evaluated the safety and efficacy of BPA for chronic thromboembolic pulmonary hypertension based on a multicenter registry. METHODS AND RESULTS: A total of 308 patients (62 men and 246 women; mean age, 61 years) underwent 1408 procedures at 7 institutions in Japan. Data were retrospectively reviewed to evaluate clinical outcome and complications. Hemodynamics were significantly improved in 249 patients in whom BPA was terminated, most often because of improvement in mean pulmonary arterial pressure or symptomatic improvement after 1154 procedures. In 196 patients who underwent follow-up right heart catheterization, improvement of hemodynamic parameters was maintained. Mean pulmonary arterial pressure decreased from 43.2±11.0 to 24.3±6.4 mm Hg after final BPA and 22.5±5.4 mm Hg at follow-up, with significant reduction of concomitant use of pulmonary hypertension-targeted therapy and oxygen supplementation. Complications occurred in 511 (36.3%), including pulmonary injury (17.8%), hemoptysis (14.0%), and pulmonary artery perforation (2.9%). Twelve patients (3.9%) died during follow-up, including 8 patients who died within 30 days after BPA. The leading causes of death were right heart failure, multiorgan failure, and sepsis. Overall survival was 96.8% (95% confidence interval, 93.7%-98.4%) at 1 and 2 years and 94.5% (95% confidence interval, 89.3%-97.3%) at 3 years, respectively, after the initial BPA procedure for all 308 patients. CONCLUSIONS: This multicenter registry suggested improved hemodynamic results after BPA. Complication rates were high, but overall survival was comparable with pulmonary endarterectomy. BPA may be an important therapeutic option in patients with chronic thromboembolic pulmonary hypertension.