Pulmonary vascular occlusion and fibrosing mediastinitis

Pulmonary Hypertension Caused by Fibrosing Mediastinitis

Pulmonary hypertension (PH) is a progressive and severe disorder in pulmonary hemodynamics. PH can be fatal if not well managed. Fibrosing mediastinitis (FM) is a rare and benign fibroproliferative disease in the mediastinum, which may lead to pulmonary vessel compression and PH. PH caused by FM (PH-FM) is a pathologic condition belonging to group 5 in the World Health Organization PH classification. PH-FM has a poor prognosis because of a lack of effective therapeutic modalities and inappropriate diagnosis. With the development of percutaneous pulmonary vascular interventional therapy, the prognosis of PH-FM has been greatly improved in recent years. This article provides a comprehensive review on the epidemiology, pathophysiologic characteristics, clinical manifestations, diagnostic approaches, and treatment modalities of PH-FM based on data from published reports and our medical center with the goal of facilitating the diagnosis and treatment of this fatal disease.

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PH-FM, as a type of rare condition in group 5 PH, has a poor prognosis because of a lack of effective therapeutic modalities and frequent misdiagnosis and underdiagnosis.

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The most prevalent trigger of FM is H-FM in the United States and TB-FM in China.

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Imaging findings, including mismatched perfusion defects in the V/Q scan, FM dyad, and FM triad are important diagnostic clues, and clinical classification facilitates decision making in diagnosis and therapeutics.

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Because of the limited efficacy of drug therapy as well as the uncertain effectiveness and high risk of surgical treatment, endovascular interventional modality is currently the preferred therapeutic option, although procedure-related complications and intrastent restenosis after PV intervention need to be addressed.

Extrinsic compression of coronary and pulmonary vasculature

Coronary artery disease from atherosclerosis induced stenosis remains the leading cause of acute coronary syndrome (ACS) and death worldwide, however extrinsic compression of coronary arteries from adjacent anatomical and pathological structures is an infrequent but important diagnosis to be aware of, especially given the nonspecific symptoms of chest pain that mimic angina in patients with pulmonary hypertension (PHT) and congenital heart disease. Non-invasive CT angiography is an invaluable diagnostic tool for detection of coronary artery compression, pulmonary artery dilatation and pulmonary vascular compression. Although established guidelines are not available for management of left main coronary artery (LMCA) compression syndrome, percutaneous coronary intervention and stent implantation remain a feasible option for the treatment, specifically for patients with a high surgical risk. Treatment of pulmonary vein or artery compression is more varied and determined by etiology. This review article is focused on detailed discussion of extrinsic compression of coronary arteries, mainly the LMCA and brief discussion on pulmonary vasculature compression by surrounding anatomical and pathological entities, with focus on pathophysiology, clinical features, complications and role of imaging in its diagnosis and management.

Refractory pleural effusion as a rare complication of pulmonary vascular stenosis induced by fibrosing mediastinitis: a case report and literature review

Fibrosing mediastinitis (FM) is a progressive, life-threatening disease characterized by extrinsic compression of mediastinal bronchovascular structures, and the clinical manifestations largely depend upon the affected structures. Pleural effusion is rarely reported in patients with FM. We herein describe a 70-year-old man who presented with recurrent breathlessness and refractory left pleural effusion. He was misdiagnosed with and treated for tuberculous pleurisy for several months. Thoracentesis revealed a transudative pleural effusion, and a contrast-enhanced computed tomography scan of the thorax showed an extensive mediastinal soft tissue mass consistent with FM. Pulmonary angiography demonstrated pulmonary artery stenosis on the right side and pulmonary vein stenosis mainly on the left side. After measurement of the pulmonary arterial pressure by right heart catheterization, the patient was diagnosed with pulmonary hypertension associated with FM. He underwent balloon angioplasty and stent implantation of the stenosed pulmonary vessels, which led to long-term improvement in his breathlessness and pleural effusion. Our systematic review of the literature highlights that pleural effusion can be an uncommon complication of FM and requires careful etiological differentiation.

Evaluation of Outcomes Following Pulmonary Artery Stenting in Fibrosing Mediastinitis

PURPOSE

Fibrosing mediastinitis is a rare disease characterized by fibrosis of mediastinal structures with subsequent constriction of the bronchi and pulmonary vessels leading to potential respiratory compromise and death. Presently, there is no effective curative treatment with available treatments focused on reducing symptomology, including placement of pulmonary artery stents. Limited studies examine the use of stents in fibrosing mediastinitis. Given this knowledge gap, we assessed stent patency, hemodynamics, complications, and secondary outcomes of clinical improvement of pulmonary artery stenting for fibrosing mediastinitis.

MATERIALS AND METHODS

Nine patients with fibrosing mediastinitis and pulmonary artery stents were retrospectively identified for inclusion (six females, three males; mean age 44.17 years, range 13-68; total 13 primary stents) from 2005 to 2018. Eight patients had history of PH. All patients had dyspnea on presentation. Seven patients had ventilation/perfusion studies demonstrating impairment. Results from computed tomography and echocardiography studies were collected to assess patency and physiologic response.

RESULTS

All patients received initial angioplasty and stenting of the right pulmonary artery (10 stents). Two patients underwent additional left-sided intervention (3 stents). Stenting significantly increased lesion luminal patency (54-79%; P < 0.005) and reduced systolic pressure gradients across stenoses (mean -9.38 mmHg; P < 0.005). Primary patency at one year was 90%. Two stents received reintervention at 276 and 497 days. 89% reported improvement in dyspnea in the initial post-stenting period. There were no mortalities or major complications.

CONCLUSION

Pulmonary artery stenting improves vascular patency and provides symptomatic relief in patients with fibrosing mediastinitis.

Thoracoabdominal compartment syndrome complicating right-sided diaphragmatic eventration with co-existent unilateral renal agenesis

Diaphragmatic eventration (DE) associated with intestinal malrotation and renal agenesis is a rare entity. The authors report a case of a 69-year-old man who had symptoms of heart failure. He had a previous imaging diagnosis of right diaphragmatic eventration and dilated cardiomyopathy. He died on the second day after the hospital admission and had a post mortem examination that confirmed complete right diaphragmatic eventration, intestinal malrotation, left renal agenesis, dilated cardiomyopathy, and anteriorly rotated right kidney and had findings suggestive of a thoracoabdominal compartment syndrome. Thoracoabdominal compartment syndrome is described as transmission of abdominal pressure through a defective diaphragm causing compression of the hemithorax viscera and mediastinal shift with a hemodynamic alteration. The association of these anomalies is rare, and the possibility of this finding in a patient with eventration should always be considered.

Multimodality Imaging of Focal and Diffuse Fibrosing Mediastinitis

Fibrosing mediastinitis is a rare benign but potentially life-threatening process that occurs because of proliferation of fibrotic tissue in the mediastinum. The focal subtype is more common and typically is associated with an abnormal immunologic response to Histoplasma capsulatum infection. Affected patients are typically young at presentation, but a wide age range has been reported, without a predilection for either sex. The diffuse form may be idiopathic or associated with autoimmunity, usually affects middle-aged and/or elderly patients, and is more common in men. For both subtypes, patients present with signs and symptoms related to obstruction or compression of vital mediastinal structures. The most common presenting signs and symptoms are cough, dyspnea, recurrent pneumonia, hemoptysis, and pleuritic chest pain. Patients with the diffuse subtype may have additional extrathoracic symptoms depending on the other organ systems involved. Because symptom severity is variable, treatment should be individualized with therapies tailored to alleviate compression of the affected mediastinal structures. Characteristic imaging features of fibrosing mediastinitis include infiltrative mediastinal soft tissue (with or without calcification) with compression or obstruction of mediastinal vascular structures and/or the aerodigestive tract. When identified in the appropriate clinical setting, these characteristic features allow the radiologist to suggest the diagnosis of fibrosing mediastinitis. Careful assessment is crucial at initial and follow-up imaging for exclusion of underlying malignancy, assessment of disease progression, identification of complications, and evaluation of treatment response. Online supplemental material is available for this article. ^©RSNA, 2019.

Sclerosing Mediastinitis Causing Unilateral Pulmonary Edema Due to Left Atrial and Pulmonary Venous Compression. A Case Report and Literature Review

Sclerosing mediastinitis (SM), previously named chronic fibrosing mediastinitis, is an inflammatory process that in its end-stage results to sclerosis around the mediastinal structures. SM is quite rare and has been correlated with inflammatory and autoimmune diseases, as well as malignancy. SM may either present in a mild form, with minor symptoms and a benign course or in a more aggressive form with severe pulmonary hypertension and subsequent higher morbidity and mortality. The diagnosis of SM may be difficult and quite challenging, as symptoms depend on the mediastinal structure that is mainly involved; quite often the superior vena cava. However, practically any mediastinal structure may be involved by the fibrotic process, such as the central airways, as well as the pulmonary arteries and veins, leading to obstruction or total occlusion. The latter may be impossible to undergo proper surgical excision of the lesion, and is considered to be a real challenge to the surgeon. We herein report a case of SM that presented with arterial and venous compression. The imaging appearance was that of unilateral pulmonary edema, associated with lung collapse. The case is supplemented by a non-systematic review of the relevant literature.

Fibrosing mediastinitis with pulmonary hypertension as a complication of pulmonary vein stenosis: A case report and review of the literature

INTRODUCTION

Fibrosingmediastinitis (FM) is caused by a proliferation of fibrous tissue in the mediastinum encasing the mediastinal viscera that results in compression of mediastinal bronchovascular structures. Pulmonary hypertension (PH) is a severe complication of FM caused by extrinsic compression of pulmonary blood vessels.

CASE PRESENTATION

Here, we present the case of a 47-year-old man who presented with a 10-year history of progressive hemoptysis and a 2-year history of shortness of breath, in whom a diagnosis of FM was made. Occlusion of the superior pulmonary veins was noted, with stenosis of the inferior pulmonary veins, leading to PH. Because the patient was a poor candidate for interventional catheterization, the preferred treatment for FM, his PH has been managed with diuretics, and he remains stable.

CONCLUSIONS

FM is a serious, potentially life-threatening condition that is best managed in specialized centers.

Pulmonary Hypertension Complicating Fibrosing Mediastinitis

Fibrosing mediastinitis is caused by a proliferation of fibrous tissue in the mediastinum with encasement of mediastinal viscera and compression of mediastinal bronchovascular structures. Pulmonary hypertension (PH) is a severe complication of fibrosing mediastinitis caused by extrinsic compression of the pulmonary arteries and/or veins.We have conducted a retrospective observational study reviewing clinical, functional, hemodynamic, radiological characteristics, and outcome of 27 consecutive cases of PH associated with fibrosing mediastinitis diagnosed between 2003 and 2014 at the French Referral Centre for PH.Fourteen men and 13 women with a median age of 60 years (range 18-84) had PH confirmed on right heart catheterization. The causes of fibrosing mediastinitis were sarcoidosis (n = 13), tuberculosis-infection confirmed or suspected (n = 9), mediastinal irradiation (n = 2), and idiopathic (n = 3). Sixteen patients (59%) were in NYHA functional class III and IV. Right heart catheterization confirmed moderate to severe PH with a median mean pulmonary artery pressure of 42 mm Hg (range 27-90) and a median cardiac index of 2.8 L/min/m (range 1.6-4.3). Precapillary PH was found in 22 patients, postcapillary PH in 2, and combined postcapillary and precapillary PH in 3. Severe extrinsic compression of pulmonary arteries (>60% reduction in diameter) was evidenced in 2, 8, and 12 patients at the main, lobar, or segmental levels, respectively. Fourteen patients had at least one severe pulmonary venous compression with associated pleural effusion in 6 of them. PAH therapy was initiated in 7 patients and corticosteroid therapy (0.5-1 mg/kg/day) was initiated in 3 patients with sarcoidosis, with 9 other being already on low-dose corticosteroids. At 1-year follow-up, 3 patients had died and among the 21 patients evaluated, 3 deteriorated, 14 were stable, and only 4 patients with sarcoidosis improved (4 receiving corticosteroids and 1 receiving corticosteroids and PAH therapy). Survival was 88%, 73%, and 56% at 1, 3, and 5 years, respectively.We found no clear clinical improvement with the use of specific PAH therapy. Corticosteroid therapy may be associated with clinical improvement, in some patients with fibrosing mediastinitis due to sarcoidosis. Although never performed for this indication, lung transplantation may be proposed in eligible patients with severe PH and fibrosing mediastinitis.

Catheter-based intervention for pulmonary vein stenosis due to fibrosing mediastinitis: The Mayo Clinic experience

Introduction

Fibrosing mediastinitis (FM) is a rare but fatal disease characterized by an excessive fibrotic reaction in the mediastinum, which can lead to life-threatening stenosis of the pulmonary veins (PV). Catheter-based intervention is currently the only viable option for therapy. However, the current literature on how best to manage these difficult cases, especially in regards to sequential interventions and their potential complications is very limited.

Methods

We searched through a database of all patients who have undergone PV interventions at the Earl H. Wood Cardiac Catheterization Laboratory in Mayo Clinic, Rochester. From this collection, we selected patients that underwent PV intervention to relieve stenosis secondary to FM.

Results

Eight patients were identified, with a mean age of 41 years (24–59 years). Five were men, and three were women. Three patients underwent balloon angioplasty alone, and five patients had stents placed. The majority of patients had acute hemodynamic and symptomatic improvement. More than one intervention was required in five patients, four patients had at least one episode of restenosis, and four patients died within four weeks of their first PV intervention.

Conclusions

We describe the largest reported case series of catheter-based intervention for PV stenosis in FM. Although catheter-based therapy improved hemodynamics, short-term vascular patency, and patient symptoms, the rate of life-threatening complications, restenosis, and mortality associated with these interventions was found to be high. Despite these associated risks, catheter-based intervention is the only palliative option available to improve quality of life in severely symptomatic patients with PV stenosis and FM. Patients with PV stenosis and FM (especially those with bilateral disease) have an overall poor prognosis in spite of undergoing these interventions due to the progressive and recalcitrant nature of the disease. This underscores the need for further innovative approaches to manage this disease.

The role of nuclear imaging in pulmonary hypertension

Pulmonary hypertension (PH) is a disease characterized by a chronic elevation of pulmonary artery pressure from various causes. Pulmonary artery hypertension (PAH) is one of subtype which results in premature death often as a result of right ventricular (RV) dysfunction. In spite of the recent progress in novel cardiac imaging techniques and new drugs for PAH, there remain significant unresolved issues including a need for earlier diagnosis, refinement of risk stratification, and monitoring the effects of treatment. Cardiac and pulmonary imaging with transthoracic echocardiography (TTE) with Doppler, magnetic resonance imaging (MRI), and computed tomography (CT) are done routinely in many clinical centers. However, routine and emerging nuclear techniques may have a pivotal role of assessment of the patient with PH, and is currently the subject of significant research. Potential Roles for Nuclear Imaging in the Evaluation of the PH Patient: (1) Evaluation of cardiac structure and function (RNA) (non-nuclear techniques would include TTE, CT, and MRI). (2) Functional imaging. This includes the use of ventilation-perfusion scintigraphy (V/Q scan) to diagnose chronic thromboembolic pulmonary hypertension (CTEPH), 123l-metaiodobenzylguanidine (MIBG) imaging to evaluate the cardiac sympathetic nervous system (non-nuclear techniques include invasive right heart catheterization and TTE). (3) Measurement of RV perfusion (with gated SPECT studies). (4) Evaluation of cardiac and pulmonary metabolism (PET scans). This review article will summarize the pathophysiology, classification, natural history, and diagnostic approach of PH. Current and emerging nuclear techniques will be discussed under the four themes of evaluation of structure, functional imaging, flow, and metabolism. These will be compared to current and emerging nuclear and non-nuclear diagnostic tests in the evaluation and management of patients with PH. We will also discuss research applications exploring new insights into flow and metabolism in the right heart and lung and the application of new radioligands.

World Health Organization group 5 pulmonary hypertension

World Health Organization (WHO) group 5 pulmonary hypertension (PH) entails a heterogeneous group of disorders that may cause PH by unclear and/or multiple mechanisms. In particular, group 5 includes PH caused by hematologic disorders, systemic diseases, metabolic disorders, chronic renal failure, and disorders leading to pulmonary vascular occlusion or compression. This article discusses common pathogenic mechanisms leading to group 5 PH, followed by a detailed overview of epidemiology, pathogenesis, and disease-specific management of the individual group 5 conditions. Off-label use of vasomodulatory therapies, typically indicated for pulmonary arterial hypertension (WHO group 1 PH), in group 5 conditions is also discussed.

Pulmonary Artery Narrowing: A Less Known Cause for Massive Hemoptysis

Chronic pulmonary artery narrowing may result from diverse causes; congenital as well as acquired. The relative hypoperfusion of the lung results in hypertrophy of multiple systemic arteries. Such patients can present with recurrent hemoptysis from hypertrophied systemic arteries, most commonly bronchial arteries. These patients remain undiagnosed for a long time because of the lack of awareness of this entity. We present three cases of chronic pulmonary artery narrowing presenting with massive hemoptysis.

Idiopathic mediastinal fibrosis with involvement of the pulmonary vessels and left main coronary artery

Idiopathic mediastinal fibrosis (IMF) is an uncommon clinical condition and the manifestations of this disease vary from a relatively benign disorder with minor symptoms to severe pulmonary vascular occlusion leading to mortality, commonly presenting a diagnostic and therapeutic challenge. Here, we present the case of a Taiwanese woman with obstruction of the left pulmonary veins and artery and stenosis of the left main coronary artery (LMCA) resulting from IMF. To our knowledge, this is the first reported case of IMF successfully treated with percutaneous balloon angioplasty with stent placement for the LMCA stenosis.

Percutaneous vascular stent implantation as treatment for central vascular obstruction due to fibrosing mediastinitis

BACKGROUND

Fibrosing Mediastinitis (FM) is a rare complication of infection with Histoplasma capsulatum that can lead to obstruction of pulmonary and systemic vasculature and large airways, often resulting in significant morbidity and mortality. Medical therapy is ineffective, and surgical intervention is often not feasible. Stent implantation offers a potential treatment for vascular obstruction due to FM, but this has not been well studied.

METHODS AND RESULTS

We conducted a retrospective review of all patients undergoing cardiac catheterization for FM. Anatomic site of stenosis and hemodynamic information before and after intervention, as well as clinical presentation and follow-up data, were recorded. From 1996 to 2008, 58 patients underwent cardiac catheterization for FM, with intervention performed in 40 (69%). A total of 77 stents were used to relieve 59 lesions (pulmonary artery=26, pulmonary vein=21, and superior vena cava=12). Significant reduction in pressure gradients (P<0.001) and increase in vessel caliber (P<0.001) were seen at all locations. Symptomatic recurrent stenosis requiring further intervention occurred in 11 patients (28%). Median time to recurrence was 115 months. Thirty-two (87%) of 37 patients for whom follow-up was available reported symptomatic improvement after stent placement.

PROCEDURE

related complications occurred in 14 patients (24%). Overall mortality was 19%, with the majority of deaths in patients with bilateral disease. Among patients with bilateral disease, intervention was associated with improved survival at 5 years.

CONCLUSION

Percutaneous vascular stent implantation is an effective therapy for central vascular obstruction due to FM, providing significant relief of anatomic obstruction and sustained clinical improvement.

Pulmonary pseudoneoplasms

CONTEXT

Not uncommonly, a surgical pathologist will be requested to review excised material, with a clinical diagnosis of cancer, in which no malignancy can be identified. Often, sampling may be the issue. However, different nonneoplastic processes may mimic cancer clinically and not be recognized histologically. These are commonly referred to as pseudoneoplasms and can involve the lung, pleura, and mediastinum.

OBJECTIVE

To review the most commonly encountered pseudoneoplasms of the thoracic cavity in surgical pathology and discuss the main differential diagnosis.

DATA SOURCES

Literature and personal review of cases with focus on inflammatory pseudotumors of the lung, organizing pneumonia, nodular lymphoid hyperplasia, apical cap, round atelectasis, and sclerosing mediastinitis with its pulmonary counterpart, hyalinizing granuloma.

CONCLUSIONS

When reviewing specimens that appear nondiagnostic for malignancy, it is important to consider one of these pseudoneoplasms in the differential diagnosis as they may explain the clinical and radiologic information.

The State of the Art in Pulmonary Vein Stenosis -Diagnosis & Treatment

Pulmonary vein stenosis is a rare but serious complication of pulmonary vein isolation to treat atrial fibrillation. Pulmonary vein angioplasty/stenting has emerged as the treatment of choice for significantly stenotic veins. Guidelines for post ablation evaluation of the pulmonary veins, including the timing and method of surveillance for possible stenosis, the criteria for intervention, the technical aspects of intervention, and finally the surveillance post intervention, are still being developed. The relatively high rate of restenosis after intervention in a subset of patients remains a great challenge. A better understanding of the pathophysiology underlying this syndrome is needed to appropriately answer many of the remaining questions. The goal of this manuscript is to describe what has been learned about this complication and its treatment from a relatively large experience in a single institution over the past decade, and provide a comprehensive review of the existing literature in order to shed as much light on the subject as is possible, while at the same time exposing the areas that need further study.

Operative strategies for pulmonary artery occlusion secondary to mediastinal fibrosis

BACKGROUND

Fibrosing mediastinitis is a rare disease characterized by an excessive fibrotic reaction in the mediastinum, which may entrap mediastinal structures including the pulmonary arteries. Our objectives were to assess the surgical strategies and outcomes of repair of pulmonary artery occlusion attributable to mediastinal fibrosis.

METHODS

With approval from the Mayo Clinic Institutional Review Board, we identified all patients with fibrosing mediastinitis who underwent an operation for relief of pulmonary artery obstruction between 1980 and 2008. Perioperative data were collected using medical records and late follow-up surveys.

RESULTS

Operative procedures to bypass or reconstruct an obstructed pulmonary artery were performed in 5 patients. Patients' median age was 40 years (range, 27 to 51 years), and all patients were symptomatic and had right ventricular hypertension. In 3 patients, a double-outlet right ventricle was constructed using a valved conduit (porcine valved conduit, n = 1; aortic homograft, n = 2) from the right ventricle to the right pulmonary artery. Two patients required complete reconstruction of the pulmonary artery confluence using a pulmonary homograft in 1 patient and a hybrid technique of autologous pericardial reconstruction and intraoperative stenting in another patient. All patients had a reduction in right ventricular pressures after operation. One patient died perioperatively owing to respiratory failure; the remaining 4 patients were alive at a median follow-up of 7.4 years (range, 0.5 to 14.7 years). One patient required late balloon dilatation of the conduit and distal pulmonary arteries 10 years after initial operation, but the remaining conduits were widely patent at late follow-up. Late functional improvement was limited owing to other complications from mediastinal fibrosis or other comorbidities.

CONCLUSIONS

Treatment of pulmonary artery occlusion attributable to mediastinal fibrosis can be challenging. Successful operative strategies include both creation of a double-outlet right ventricle and complete reconstruction of the pulmonary artery confluence. Hybrid techniques of both conduit placement and stenting should also be considered for patients with occluded pulmonary arteries.

Lymph node enlargement in pulmonary arterial hypertension due to chronic thromboembolism

The aim of this study was to determine the prevalence and location of enlarged mediastinal and hilar lymph nodes in patients with pulmonary arterial hypertension (PAH) due to chronic pulmonary thromboembolism (CPTE) and to identify possible causes. Thoracic CT images of 85 patients (43 men and 42 women, aged 18-80 years) with PAH in whom CPTE was confirmed at surgery (n = 75) or angiography and angioscopy (n = 10) were evaluated by two thoracic radiologists to determine the presence, size and location of lymph nodes more than 1 cm in the short axis. The presence of pleural and pericardial effusions and parenchymal abnormalities were also noted. Enlarged lymph nodes were identified in 38 patients (44.7%), including 11 with possible causes of lymphadenopathy other than CPTE. In the 27 patients with CPTE alone, 67 enlarged lymph nodes were detected (average 2.5 per patient). Nine patients had three or more enlarged lymph nodes. The most common sites of lymph node enlargement were American Thoracic Society locations 7 (n = 13), 6 (n = 10), 11L (n = 9), 10R (n = 7) and 4R (n = 7). Pleural and pericardial effusions were more common in patients with CPTE who also had lymphadenopathy than in the group with no lymphadenopathy (P < 0.05). Lymph node enlargement is common in patients with PAH caused by CPTE. The frequent association of lymphadenopathy with pleural and pericardial effusions suggest a possible pathophysiological mechanism of increased lymphatic flow caused by right heart failure.

Pulmonary Vascular Disease

The pulmonary vasculature is an anatomic compartment that is frequently overlooked in the histologic review of lung biopsy samples, other than those obtained specifically to assess pulmonary vascular disease.1 Though often of a nonspecific nature, the histologic pattern of vascular remodeling may at times suggest its underlying pathogenesis and provide clues to the cause of pulmonary hypertension.2 Disproportionately severe vascular pathology may further indicate alternate disease processes, such as congestive heart failure or thromboemboli, contributing to the patient’s overall respiratory condition.

Chronic thromboembolic pulmonary hypertension

The description of organized thrombus in major pulmonary arteries can be found in autopsy reports dating back to the late nineteenth and early twentieth centuries. Not until the 1950s was the antemortem diagnosis and clinical syndrome of chronic thrombotic obstruction of the major pulmonary arteries better characterized. The first surgical attempt to remove the adherent thrombus from the vessel wall occurred in 1958. This operation provided the conceptual foundation for the distinction between acute and chronic thromboembolic disease of the pulmonary vascular bed, and established that an endarterectomy, and not an embolectomy, would be necessary if a surgical remedy for this disease was to be successful.

Evaluation of patients for pulmonary endarterectomy

Chronic thromboembolic obstruction of the pulmonary vascular bed has been increasingly recognized as a treatable form of pulmonary hypertension, with surgery referred to as a pulmonary endarterectomy. Careful evaluation of patients with pulmonary hypertension and proper selection of those with surgically accessible, chronic thromboembolic disease are critical determinants for a successful outcome from this operation. This article describes the clinical presentation, appropriate evaluation, and an approach to surgical selection for patients with chronic thromboembolic pulmonary hypertension.

Unilateral pulmonary edema due to pulmonary venous obstruction from fibrosing mediastinitis

An unusual case of fibrosing mediastinitis with obstruction of the inferior and superior left pulmonary veins and severe narrowing of the right pulmonary artery, disclosed after unilateral pulmonary edema, is described. The 18-year-old male patient had a long history of cough, progressive dyspnea and recurrent hemoptysis and the possible diagnosis of "interstitial fibrosis" from a previous lung biopsy. The diagnosis and the pulmonary vessels involvement were suspected after right heart catheterization combined with transesophageal echocardiography and confirmed during urgent thoracotomy and at postmortem examination.

Life-threatening hemoptysis caused by chronic idiopathic pulmonary hilar fibrosis with unilateral pulmonary vein occlusion

We present the case of a patient who has a life-threatening hemoptysis caused by occlusion of the right pulmonary vein owing to external compression by excessive fibrous tissue. Because the patient's lung was essentially nonfunctional and hemoptysis persisted, we performed a pneumonectomy on her. Pathological analysis of the lung showed severe hypertensive changes in the arterial and venous microvasculature of the lung. Parenchymal-pleural to intercostal systemic venous connections had developed, facilitating venous drainage of the lung circulation. Upon review of the patient's history and the pathological and radiological evidence, we concluded that the pathological changes were caused by a variant of mediastinal fibrosis termed chronic idiopathic pulmonary hilar fibrosis, of which only a few cases have been described in the literature. A detailed case history and review of the literature are presented.

Fibrosing mediastinitis with peripheral airway dilatation and central pulmonary artery occlusion

We present a case of fibrosing mediastinitis causing peripheral airway abnormalities on CT consisting of bronchial dilatation and wall thickening due to longstanding central pulmonary artery obstruction. The peripheral airway dilatation is similar in appearance to that which has been described in patients with chronic pulmonary embolism.

Chronic thromboembolic pulmonary hypertension

During the past 2 decades, there has been a steady rise in the number of patients with chronic thromboembolic pulmonary hypertension (CTEPH) undergoing surgery and in the number of programs worldwide dedicated to the diagnosis and management of this patient population. This article discusses the natural history and clinical presentation of CTEPH, the evaluation of patients for pulmonary thromboendarterectomy, and the outcomes following surgery, along with a brief review of the procedure as performed at the University of California, San Diego.

Clinical classification of pulmonary hypertension

In 1998, during the Second World Symposium on Pulmonary Hypertension (PH) held in Evian, France, a clinical classification of PH was proposed. The aim of the Evian classification was to individualize different categories sharing similarities in pathophysiological mechanisms, clinical presentation, and therapeutic options. The Evian classification is now well accepted and widely used in clinical practice, especially in specialized centers. In addition, this classification has been used by the U.S. Food and Drug Administration and the European Agency for Drug Evaluation for the labeling of newly approved medications in PH. In 2003, during the Third World Symposium on Pulmonary Arterial Hypertension held in Venice, Italy, it was decided to maintain the general architecture and philosophy of the Evian classification. However, some modifications have been proposed, mainly to abandon the term "primary pulmonary hypertension" and to replace it with "idiopathic pulmonary hypertension"; to reclassify pulmonary veno-occlusive disease and pulmonary capillary hemangiomatosis; to update risk factors and associated conditions for pulmonary arterial hypertension and to propose guidelines in order to improve the classification of congenital systemic-to-pulmonary shunts.

Pulmonary thromboendarterectomy in a patient with giant cell arteritis

This report describes the case of a young woman presenting with signs and symptoms of chronic thromboembolic pulmonary hypertension who underwent pulmonary thromboendarterectomy (PTE) with concomitant coronary artery bypass. She died in the intensive care unit 1 day postoperatively. At autopsy the patient was found to have giant cell arteritis of the pulmonary arteries and ascending aorta. It is important to differentiate this disease from chronic thromboembolic pulmonary hypertension because its management and that of systemic vasculitis differs considerably.

Stent placement in the treatment of pulmonary artery stenosis secondary to fibrosing mediastinitis

This article describes an initial experience with stent placement in three patients with severe pulmonary artery stenosis secondary to fibrosing mediastinitis. All three patients were severely symptomatic on admission and all three were asymptomatic after treatment and remained symptom-free approximately 1 year after treatment.

Percutaneous pulmonary artery and vein stenting: a novel treatment for mediastinal fibrosis

Mediastinal fibrosis is a rare consequence of infection with the fungus Histoplasma capsulatum that can lead to occlusion of large pulmonary arteries and veins and mainstem bronchi. Medical and surgical treatments for this disorder have been ineffective. We describe successful treatment for central pulmonary arterial and venous obstruction due to mediastinal fibrosis in four patients using percutaneously placed intravascular stents. Patients were severely limited, World Health Organization functional class III or IV. At the time of right and left heart catheterization, stents were placed in pulmonary arteries (n = 1), veins (n = 2), or both (n = 1) to relieve vascular obstruction resulting from mediastinal fibrosis. Immediate hemodynamic and clinical improvement was observed in all patients. Three of the four patients have had sustained improvement in exercise tolerance, from 3.5 mo to 4.5 yr after stent placement. The only complication was a self-limited pulmonary hemorrhage in one patient. Our initial experience suggests that percutaneous stent placement to relieve central pulmonary arterial or venous obstruction due to mediastinal fibrosis is an effective new treatment modality.

Fibrosing Mediastinitis

Fibrosing mediastinitis is a rare benign disorder caused by proliferation of acellular collagen and fibrous tissue within the mediastinum. Although many cases are idiopathic, many (and perhaps most) cases in the United States are thought to be caused by an abnormal immunologic response to Histoplasma capsulatum infection. Affected patients are typically young and present with signs and symptoms of obstruction or compression of the superior vena cava, pulmonary veins or arteries, central airways, or esophagus. There may be two types of fibrosing mediastinitis: focal and diffuse. The focal type usually manifests on computed tomographic (CT) or magnetic resonance (MR) images as a localized, calcified mass in the paratracheal or subcarinal regions of the mediastinum or in the pulmonary hila. The diffuse type manifests on CT or MR images as a diffusely infiltrating, often noncalcified mass that affects multiple mediastinal compartments. CT and MR imaging play a vital role in the diagnosis and management of fibrosing mediastinitis.

Treatment of pulmonary artery compression due to fibrous mediastinitis with endovascular stent placement

We present the case of a 32-year-old woman with high-grade right pulmonary artery stenosis secondary to fibrous mediastinitis. The patient was managed with balloon angioplasty and stent placement. Only 15 cases of this nature have been reported in the literature, and this is one of the first to be managed with endovascular stent placement.

"High probability" perfusion lung scans in pulmonary venoocclusive disease

"High-probability" ventilation/perfusion (V/Q) lung scans generally indicate proximal pulmonary arterial occlusion by thromboemboli or, rarely, other processes such as tumors, fibrosing mediastinitis, or vasculitis. In this report we describe three patients with high probability V/Q scans in whom pulmonary angiography failed to demonstrate arterial occlusion. All three patients were determined to have pulmonary venoocclusive disease (PVOD). In two patients, a tissue diagnosis of PVOD was made, in one case with explanted tissue taken after a successful heart-lung transplant and in the other case with tissue taken at autopsy. PVOD in the third patient was diagnosed with pulmonary venography. A potential explanation for the discrepancy between perfusion lung scan and pulmonary angiographic findings in PVOD is discussed.

[Chronic sclerosing mediastinitis: infrequent cause of unilateral diaphragmatic paralysis]

Chronic sclerosing mediastinitis (CSM) is a rare disease whose etiology varies and which usually develops through mediastinal compression syndromes, generally due to occlusion of the superior vena cava. We report a case of CSM diagnosed after a chance finding of unilateral diaphragm paralysis, a circumstance not previously reported in the literature. We review the clinical, radiological and histological features of CSM.

Percutaneous stenting of right pulmonary artery stenosis in fibrosing mediastinitis

Pulmonary artery stenosis is an uncommon complication of fibrosing mediastinitis. Previous medical and surgical therapies have provided limited clinical efficacy without objective evidence of clinical improvement. With the advantages of limited invasiveness and absent need for prolonged drug therapy, percutaneous stent deployment to relieve pulmonary artery obstruction represents a novel treatment for this rare disorder.

From the archives of the AFIP: pulmonary vasculature: hypertension and infarction

Pulmonary hypertension is the hemodynamic consequence of vascular changes within the precapillary (arterial) or postcapillary (venous) pulmonary circulation. These changes may be idiopathic, as in primary pulmonary hypertension or pulmonary veno-occlusive disease, but more commonly they represent a secondary response to alterations in pulmonary blood flow. The pulmonary and systemic bronchial circulations form broad anastomoses that largely prevent infarction except in settings of markedly elevated pulmonary venous pressure, underlying malignancy, or excessive embolic burden. Causes of precapillary pulmonary hypertension include long-standing cardiac left-to-right shunt, chronic thromboembolic disease, and widespread pulmonary embolism arising from intravascular malignant cells, parasites, or foreign materials. The classic radiologic features of precapillary pulmonary hypertension are central arterial enlargement, sharply pruned peripheral vascularity, and right-sided heart hypertrophy and chamber dilatation. Postcapillary pulmonary hypertension may develop secondary to focal venous constriction or to compromised pulmonary venous drainage due to left atrial neoplasia, mitral stenosis, or left ventricular failure. Radiologic manifestations of postcapillary pulmonary hypertension include prominent septal lines, small pleural effusions, and occasionally air-space opacities. In addition, radiologic evaluation of postcapillary pulmonary hypertension may demonstrate evidence of pulmonary arterial hypertension, secondary to the retrograde transmission of elevated pulmonary venous pressure across the capillary bed.

A case of fibrosing mediastinitis with obstruction of superior vena cava and downhill esophageal varices: a rare cause of upper gastrointestinal hemorrhage

Fibrosing mediastinitis (FM) is an excessive fibrotic reaction that occurs in the mediastinum and may lead to compression of mediastinal structures (especially vascular or bronchial). In the present study we describe the first case report of FM, in a patient who developed downhill esophageal varices and bleeding, which was secondary to superior vena cava obstruction.

Evaluation of patients with suspected chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) can be a difficult diagnosis to establish, typically requiring a high index of suspicion on the part of the clinician when challenged by a patient reporting exertional dyspnea. The importance of this diagnosis is heightened by the appreciation that it is a potentially curable form of pulmonary hypertension, by a surgical procedure called pulmonary thromboendarterectomy. This article highlights the clinical presentation, evaluation, and criteria for surgical candidacy of those patients suspected of having CTEPH.

Fibrosing mediastinitis: CT and MR findings

The aim of this study is to present the computed tomography (CT) and magnetic resonance (MR) findings in three cases of fibrosing mediastinitis, probably secondary to tuberculosis. Two patients had diffuse involvement of the mediastinum and one patient presented with a posterior mediastinal mass. On CT, the patients with diffuse involvement showed infiltrating soft-tissue masses with multiple foci of dense calcifications. One of these lesions enhanced mildly with contrast and one did not enhance. On MR examination, diffuse masses were of heterogeneous, intermediate and low signal on T1-weighted images (n = 2) and were of homogeneous low signal (n = 1) or heterogeneous (n = 1) signal intensity on T2-weighted images. After administration of Gd-DTPA, these mediastinal masses showed heterogeneous enhancement. The posterior mediastinal mass showed homogeneous pronounced enhancement on CT and was homogeneous with intermediate T1 signal intensity and hypointense T2 signal intensity. The CT findings of an infiltrative or well-defined mediastinal mass with scattered calcifications should suggest the diagnosis of fibrosing mediastinitis in the appropriate clinical setting. Although the appearance of calcification on MR are not specific, this technique provides further information than CT especially in those cases in which the lesions appear noncalcified, because MR imaging revealed areas of low signal intensity characteristic of fibrous tissue.

The radiographic findings of fibrosing mediastinitis

We retrospectively reviewed the radiographic findings of fibrosing mediastinitis (FM) in 33 patients. Imaging studies included chest radiographs, computed tomographic scans, magnetic resonance imaging examinations, esophograms, ventilation perfusion scans, angiograms, and venograms. Findings include bronchial narrowing in 11 patients (33 percent), pulmonary artery obstruction/narrowing in 6 patients (18 percent), esophageal narrowing in 3 patients (9 percent), and superior vena cava obstruction/narrowing in 13 patients (39 percent). Two distinctly different radiographic patterns were identified: a localized pattern seen in 27 patients (82 percent) that frequently contained calcification and a diffuse pattern seen in 6 patients (18 percent) that did not contain calcification. The localized pattern is most likely due to histoplasmosis and does not show radiographic evidence of improvement with steroid therapy. The diffuse pattern may more likely be truly idiopathic or of a noninfectious etiology. Several patients with the diffuse pattern showed radiographic evidence of improvement with steroid therapy.

Case report: fluconazole therapy in histoplasma mediastinal granuloma

A 41-year-old man presented with night sweats, fever, and substernal chest pain approximately 5 months after being treated for community-acquired pneumonia. Chest radiograph revealed a mediastinal mass that was confirmed by computed tomography (CT) of the thorax. During surgery, enlarged paratracheal lymph nodes and a mass surrounding the right lower lobe bronchus and bronchus intermedius were found. Multiple biopsies from the mass showed that it consisted mainly of acellular fibrous tissue, but a small number of fungal forms typical of Histoplasma capsulatum were seen at the edged of the fibrotic reaction. The lymph nodes contained granulomatous inflammation and areas of necrosis, but no organisms were identified. The patient was treated with fluconazole for 6 weeks with resolution of symptoms. After completion of therapy, a follow-up CT scan of the thorax showed involution of the mediastinal mass. There has been no recurrence of symptoms or radiographic abnormalities for 24 months since cessation of fluconazole. This case illustrates isolated mediastinal involvement by histoplasmosis and suggests that therapy with fluconazole at this stage may prevent the often devastating late complications of mediastinal fibrosis.