Pulmonary Hypertension Caused by Fibrosing Mediastinitis

Pulmonary artery vasodilators for treatment of pulmonary hypertension complicating fibrosing mediastinitis

Fibrosing mediastinitis (FM) is a heterogeneous disease characterized by sclerosing fibrosis of mediastinal structures. Pulmonary hypertension (PH) may complicate the course of the disease and can contribute significantly to the morbidity of FM. Due to the rarity and complexity of the disease, evidence-based guidelines are not currently available, and the optimal treatment approach is unknown. Management approaches should be individualized, and current techniques are often unsatisfactory. Here, we present two cases of PH complicating FM that were managed using pulmonary artery vasodilator therapy with excellent hemodynamic response.

Mediastinal Cryobiopsy for Pathological Diagnosis of Fibrosing Mediastinitis-Associated Pulmonary Hypertension

INTRODUCTION

Fibrosing mediastinitis is a benign but fatal disorder characterized by the proliferation of fibrous tissue in the mediastinum, causing encasement of mediastinal organs and extrinsic compression of adjacent bronchovascular structures. FM-associated pulmonary hypertension (FM-PH) is a serious complication of FM, resulting from the external compression of lung vessels. Pathologic assessment is important for etiologic diagnosis and effective treatment of this disease.

CASE PRESENTATION

A 59-year-old male patient presented at our hospital and was diagnosed with FM-PH. He declined surgical biopsy that is the reference standard for pathologic assessment, in consideration of the potential risks. Therefore, an endobronchial ultrasound examination was performed, which identified the subcarinal lesion. Under ultrasound guidance, four needle aspirations were carried out, followed by one cryobiopsy. Histopathological examination of transbronchial needle aspiration specimens was inconclusive, while samples from cryobiopsy suggested a diagnosis of idiopathic FM. Further immunophenotyping demonstrated the infiltration of lymphocytes, macrophages, and FOXP3-positive cells in FM-PH.

CONCLUSION

Mediastinal cryobiopsy might be a novel and safe option for FM-PH patients who are unwilling or unsuitable for surgical procedure.

A rare sequelae of esophageal perforation: Fibrosing mediastinitis

Fibrosing mediastinitis (FM) is a rare disease caused by different causes. If left untreated, the prognosis is poor. The common causes of FM are Tuberculosis and Histoplasma capsulatum infection. Esophageal perforation is also a rare condition that is often easily under- and mis-diagnosed due to the lack of specificity of symptoms. Here we report a case of FM caused by esophageal perforation.

Potential Value of FAPI PET/CT in the Detection and Treatment of Fibrosing Mediastinitis: Preclinical and Pilot Clinical Investigation

Fibrosing mediastinitis (FM) is a rare proliferative disease within the mediastinum that leads to pulmonary hypertension, which has been regarded as a major cause of death. This study aims to evaluate the potential value of fibroblast activation protein inhibitor (FAPI)-PET/CT in the integration of diagnosis and treatment of FM through targeting FAPI in fibrosis rats and provide a theoretical basis for clinical management of FM patients. By performing a 18F-FAPI PET/CT scan, the presence of FAPI-avid in the fibrotic lesion was determined. Through a fibrosis rat model, 18F-FAPI-74 was used for lesion imaging and 177Lu-FAPI-46 was utilized to investigate the potential therapeutic effect on FM in vivo. In addition, biodistribution analysis and radiation dosimetry were carried out. With the 177Lu-FAPI-46 pharmacokinetic data of rats as the input, the estimated dose for female adults was computed, which can provide some useful information for the safe application of radiolabeled FAPI in the detection and treatment of FM in patients. Then, major findings on the use of FAPI PET/CT and SPECT/CT in FM were presented. 18F-FAPI-74 showed a high-level uptake in FM lesions of patients (SUVmax 7.94 ± 0.26), which was also observed in fibrosis rats (SUVmax 2.11 ± 0.23). Consistently, SPECT/CT imaging of fibrosis rats also revealed that 177Lu-FAPI-46-avid was active for up to 60 h in fibrotic lesions. In addition to this robust diagnostic performance, a possible therapeutic impact was evaluated as well. It turned out that no spontaneous healing of lesions was observed in the control group, whereas there was complete healing on day 9, day 11, and day 14 in the 30, 100, and 300 MBq groups, respectively. With a significant difference in the free of event rate in the Kaplan-Meier curve among four groups (P < 0.001), a dose of 300 MBq displayed the best therapeutic effect, and no obvious damage was observed in the kidney. Furthermore, organ-absorbed doses and an effective dose (0.4320 mSv/MBq) of 177Lu-FAPI-46 presumed for patients were assumed to give a preliminary indication of its safe use in clinical practice. In conclusion, 18F-FAPI-46 PET/CT can be a potentially valuable tool for the diagnosis of FM. Of note, 177Lu-FAPI-46 may be a novel and safe radiolabeled reagent for the integration of diagnosis and treatment of FM.

Successful simultaneous stenting of a pulmonary artery and vein in pulmonary vascular stenosis due to silicosis. Case report and literature review

A 58-year-old patient was admitted to the emergency department due to severe respiratory insufficiency. Anamnesis revealed that the patient had experienced increasing stress dyspnea for a few months. Upon imaging, an acute pulmonary embolism was excluded, but peribronchial and hilar soft tissue proliferation with compression of central parts of the pulmonary circulation was found. The patient had a history of silicosis. The histology report showed tumor-free lymph node particles with prominent anthracotic pigment and dust depositions without evidence of IgG4-associated disease. The patient was administered steroid therapy and underwent simultaneous stenting of the left interlobular pulmonary artery and the upper right pulmonary vein. As a result, a significant improvement in symptoms and physical performance was achieved. The diagnosis of inflammatory or, in particular, fibrosing mediastinal processes can be challenging and important clinical symptoms must be taken into account, especially if the pulmonary vasculature is involved. In such cases, the possibility of interventional procedures should be examined in addition to drug therapy options.

Chest X-ray features facilitate screening for pulmonary hypertension caused by fibrosing mediastinitis

Background

Misdiagnosis and underdiagnosis of pulmonary hypertension caused by fibrosing mediastinitis (PH-FM) are considerably prevalent due to unspecific symptoms and as well as the lack of awareness of this fatal disease.

Objectives

The aim of this study was to evaluate the diagnostic accuracy of the chest X-ray (CXR) for screening the patients with PH-FM from those with pulmonary hypertension (PH).

Design

This was a retrospective observational cohort study.

Methods

The patients with suspected PH were recruited between October 2014 and October 2020. All the clinical data and CXR findings were collected. The sensitivity, specificity, and likelihood ratio of the CXR features were calculated. Logistic regression was used to identify the factors associated with the CXR characteristics and FM and to generate a prediction model. Finally, the diagnostic efficiency of the prediction model was evaluated using nomogram and internal validation.

Results

The patients with PH-FM (n = 36) and PH caused by the diseases other than FM (PH-non-FM, n = 62) were enrolled. The CXR features, including atelectasis, pleural effusion, consolidation, nodules, calcification, interlobular septal thickening, and interstitial reticulation, were more prevalent in patients with PH-FM than in those with PH-non-FM (all p < 0.05). Atelectasis had a specificity of 97%, a sensitivity of 50%, and a greater accuracy for diagnosing of PH-FM [area under the curve (AUC) = 0.720; 95% CI: 0.634-0.806] than the other factors did. The combination of tuberculosis, natural logarithmic NT-proBNP (lnBNP), atelectasis, pleural effusion, and prominent right heart border constituted a prediction model to distinguish the PH-FM from the PH-non-FM, with a sensitivity of 91.7% and a specificity of 83.9%. The model demonstrated good prediction performance by showing an AUC of 0.922 (95% CI: 0.861-0.983) in the internal validation.

Conclusion

In this study, atelectasis was the most specific and accurate CXR characteristic for identifying PH-FM in the PH patients. The combination of atelectasis, pleural effusion, prominent right heart border, tuberculosis, and lnBNP constituted a prediction model that distinguished the PH-FM patients from the PH-non-FM ones with good performance.