[Genetic counselling and testing in pulmonary arterial hypertension - A consensus statement on behalf of the International Consortium for Genetic Studies in PAH - French version]

Pulmonary arterial hypertension (PAH) is a rare disease that can be caused by (likely) pathogenic germline genomic variants. In addition to the most prevalent disease gene, BMPR2 (bone morphogenetic protein receptor 2), several genes, some belonging to distinct functional classes, are also now known to predispose to the development of PAH. As a consequence, specialist and non-specialist clinicians and healthcare professionals are increasingly faced with a range of questions regarding the need for, approaches to and benefits/risks of genetic testing for PAH patients and/or related family members. We provide a consensus-based approach to recommendations for genetic counselling and assessment of current best practice for disease gene testing. We provide a framework and the type of information to be provided to patients and relatives through the process of genetic counselling, and describe the presently known disease causal genes to be analysed. Benefits of including molecular genetic testing within the management protocol of patients with PAH include the identification of individuals misclassified by other diagnostic approaches, the optimisation of phenotypic characterisation for aggregation of outcome data, including in clinical trials, and importantly through cascade screening, the detection of healthy causal variant carriers, to whom regular assessment should be offered.

Acute venodilation properties of low-dose intravenous nitroglycerine in pulmonary veno-occlusive disease: a case report

Background

The use of pulmonary vasodilators for pulmonary arterial hypertension (PAH) has led to a favourable prognosis. In contrast, pulmonary veno-occlusive disease (PVOD) is characterized by the possibility of severe pulmonary oedema after specific PAH therapy. Pulmonary oedema presumably develops in association with pulmonary arterial vasodilation without concomitant pulmonary venodilation. The venous circulation maximally dilates with small amounts of nitroglycerine.

Case summary

A 59-year-old woman with advanced PVOD was referred to our hospital. We performed a right heart catheterization after administering combination therapy with selexipag and macitentan, and intravenous nitroglycerine at 0.2 and 0.4 μg/kg/min decreased pulmonary arterial wedge pressure (PAWP) and mean pulmonary arterial pressure (PAP) to minimal levels. The final dose of 1 μg/kg/min yielded an ∼20% decrease in mean PAP and pulmonary vascular resistance (PVR).

Discussion

Here, we described the acute effect of intravenous nitroglycerine on PAWP and PVR in a patient with PVOD. This case highlights the venodilation response even in advanced PVOD, suggesting the importance of further research into selective venous dilators as potent therapy.

Diagnosis and management of pulmonary veno-occlusive disease

INTRODUCTION

Pulmonary veno-occlusive disease (PVOD) is an orphan disease and uncommon etiology of pulmonary arterial hypertension (PAH) characterized by substantial small pulmonary vein and capillary involvement.

AREAS COVERED

PVOD, also known as 'PAH with features of venous/capillary involvement' in the current ESC/ERS classification.

EXPERT OPINION

In recent years, particular risk factors for PVOD have been recognized, including genetic susceptibilities and environmental factors (such as exposure to occupational organic solvents, chemotherapy, and potentially tobacco). The discovery of biallelic mutations in the EIF2AK4 gene as the cause of heritable PVOD has been a breakthrough in understanding the molecular basis of PVOD. Venous and capillary involvement (PVOD-like) has also been reported to be relatively common in connective tissue disease-associated PAH (especially systemic sclerosis), and in rare pulmonary diseases like sarcoidosis and pulmonary Langerhans cell granulomatosis. Although PVOD and pulmonary arterial hypertension (PAH) exhibit similarities, including severe precapillary PH, it is essential to differentiate between them since PVOD has a worse prognosis and requires specific management. Indeed, PVOD patients are characterized by poor response to PAH-approved drugs, which can lead to pulmonary edema and clinical deterioration. Due to the lack of effective treatments, early referral to a lung transplantation center is crucial.

Case report: pulmonary veno-occlusive disease: a rare but fatal cause of pulmonary hypertension in a patient following allogeneic stem cell transplantation

Pulmonary veno-occlusive disease (PVOD) represents a rare and challenging form of pulmonary hypertension, characterized by preferential remodelling of the pulmonary venules. PVOD may be idiopathic as well as related to other conditions with environmental and genetic factors contributing to its development. Recently, bi-allelic mutations in the EIF2AK4-gene have been identified as a cause of heritable PVOD. PVOD shares an overlapping disease phenotype with pulmonary arterial hypertension (PAH) and is regularly misdiagnosed as such, although differentiation between these two conditions is important because of the different prognosis and therapeutic approach. The diagnosis of PVOD is frequently delayed because of the complex diagnostic process. The gold standard remains histology with widespread obliteration of small pulmonary veins by fibrous intimal thickening and patchy capillary proliferation as the pathological hallmark. At present, neither treatment guidelines nor curative medical therapies are available for PVOD. Because of the progressive nature of the disease, a quick referral for lung transplantation remains the only definitive therapy in subjects below the age of 65.

Mitomycin induced pulmonary veno-occlusive disease

Pulmonary veno-occlusive disease (PVOD) is a rare but devastating cause of pulmonary hypertension (PH) characterized by preferential remodeling of the pulmonary venules. Mitomycin-C (MMC) is an alkylating agent commonly used in chemotherapy with documented lung toxicity as well as PVOD adverse effect. The incidence of PVOD in patients with anal cancer is much higher than in those with idiopathic PVOD, especially following treatment with MMC. An accurate diagnosis of PVOD can be made based on noninvasive investigations utilizing oxygen parameters, low diffusing capacity for carbon monoxide and characteristic signs on high-resolution computed tomography of the chest. No evidence-based medical therapy exists for PVOD at present and lung transplant remains the preferred definitive therapy for eligible patients. We present a case of autopsy confirmed MMC induced PVOD in a patient with metastatic anal cancer.

Echocardiography Monitoring of Pulmonary Hypertension after Pediatric Hematopoietic Stem Cell Transplantation: Pediatric Pulmonary Arterial Hypertension and Pulmonary Veno-Occlusive Disease after Hematopoietic Stem Cell Transplantation

Pulmonary hypertension (PH) is associated with high morbidity in children undergoing hematopoietic stem cell transplantation (HSCT). However, owing to the lack of sequential echocardiography, the nature of the condition is not fully understood. This study was conducted to investigate whether routine echocardiography performed after HSCT could detect patients with PH at an earlier stage and elucidate the role of intervention using tadalafil. The study population comprised 93 consecutive children age <18 years who underwent a total of 109 HSCTs. All patients underwent routine transthoracic echocardiography during HSCT. Four children (4%) with a median age of 4 years (range, 0.7 to 6 years) were found to have PH, and their median tricuspid regurgitation peak velocity (TRV) was 4.1 m/s (range, 3.5 to 4.2 m/s). PH was diagnosed at a median of 52 days (range, 21 to 118 days) after HSCT. Three of them were diagnosed with neuroblastoma, and 1 was diagnosed with infantile leukemia. One patient developed PH after autologous HSCT, and 3 received killer immunoglobulin-like receptor ligand-mismatched cord blood. Busulfan was used for conditioning in all patients, and the proportion of patients receiving this medication was significantly higher in the PH group compared with the non-PH group (100% versus 30%; P = .011). Three of the 4 patients had a durable response (TRV ≤2.8 m/s) at a median of 46 days (range, 14 to 79 days) after starting treatment with tadalafil. No patient experienced exacerbation of PH, and treatment was completed at median of 96 days (range, 46 to 212 days). Our data suggest that routine echocardiography monitoring after HSCT should be considered in children receiving busulfan, although the precise follow-up timing needs further study. In addition, safe and effective administration of tadalafil must be ensured by close monitoring.

Dyspnoea and diffuse pulmonary nodules in a patient with pulmonary veno-occlusive disease: a case report and literature review

Pulmonary veno-occlusive disease (PVOD) is a rare type of pulmonary hypertension characterized by capillary damage or arterial pulmonary hypertension. Early lung transplantation is the only effective treatment for PVOD because of the lack of specificity in its clinical manifestations and its rapid progression and poor prognosis. A 28-year-old woman presented with exertional dyspnoea. A chest computed tomography scan revealed diffuse centrilobular ground glass opacities in both lungs, a ratio of the transverse diameter of the main pulmonary trunk to the ascending aorta of >1, and enlargement of the right ventricle and right atrium. A right atrial floating catheter test showed right ventricular pressure of 82/0/4 mmHg, mean pulmonary artery pressure of 83/34/53 mmHg, and pulmonary artery wedge pressure of 15/8/12 mmHg. A mutation was found in the eukaryotic translation initiation factor 2 alpha kinase 4 (EIF2AK4) gene. Thus, the patient was diagnosed with PVOD and subsequently given standard bosentan treatment (62.5 mg twice a day). However, after 6 months of follow-up, there was no significant improvement in the pulmonary artery pressure or activity tolerance (6-minute walking test). Therefore, cardiopulmonary transplantation was performed. Early diagnosis and timely treatment of PVOD may improve the patient’s prognosis.

[Familial pulmonary veno-occlusive disease with a composite biallelic heterozygous EIF2AK4 mutation]

Pulmonary veno-occlusive disease (PVOD) is a rare cause of pulmonary hypertension. Heritable and sporadic forms have been distinguished. Hypoxemia, profound reduction in the diffusion of carbon monoxide and haemodynamic confirmation of pre-capillary pulmonary hypertension are the major diagnostic criteria. Thoracic CT scanning and a response to pharmaceutical therapy provide additional information to confirm the diagnosis. A 52-year-old patient, three of whose siblings had pulmonary hypertension, was admitted with dyspnoea, malaise and palpitations. Right heart catheterisation confirmed pre-capillary pulmonary hypertension. A search for an EIF2AK4 mutation was carried out, and this showed a composite biallelic heterozygous mutation compatible with the diagnosis of familial PVOD, identical to that showed in one of his brothers. Given the signs of severity of the disease and the diagnosis of PVOD, whose response to pharmaceutical therapy is often poor, the patient was placed on a waiting list for lung transplantation. Despite a similar diagnosis in 3 brothers and follow-up proposed 11 years before the diagnosis, pulmonary hypertension appeared within a few weeks and led immediately to a severe clinical situation. Annual clinical and echocardiographic monitoring had been strongly advised to the patient, but had not allowed diagnosis at a mild or moderate stage of the disease. This clinical case shows that the identification of factors predicting the development of heritable PVOD at a pre-symptomatic stage is an important issue for clinical research.

[Pulmonary involvement in cancers]

Die Lunge ist bei Tumorerkrankungen sehr oft und auf sehr vielfältige Weise betroffen. Das Lungenkarzinom ist eine der häufigsten Tumorerkrankungen und erfährt gerade in den letzten Jahren eine erhebliche Erweiterung der Therapiemöglichkeiten. Die Lunge ist zudem ein häufiges Metastasierungsorgan verschiedenster Tumorentitäten. Aber auch Therapieansätze wie Tyrosinkinase- und Checkpointinhibitoren, chimäre Antigenrezeptorzelltherapien oder strahlentherapeutische Verfahren können pulmonale Nebenwirkungen verursachen. Schließlich gibt es viele Patienten, deren pulmonale Grunderkrankung auf den klinischen Verlauf und die Prognose der Tumorerkrankung Einfluss nimmt und ihrerseits beeinflusst werden kann. Beispielhaft werden verschiedene Aspekte wie pulmonale venookklusive Erkrankung, chronisch-obstruktive Atemwegserkrankung und idiopathische pulmonale Fibrose diskutiert.

Pulmonary capillary hemangiomatosis-predominant vasculopathy in a patient with rheumatoid arthritis-associated interstitial lung disease: An autopsy report

Pulmonary capillary hemangiomatosis (PCH) is a rare cause of pulmonary hypertension (PH) associated with poor prognosis. Clinically, it is characterized by severe hypoxemia, centrilobular ground-glass opacities on computed tomography, and pulmonary congestion triggered by pulmonary vasodilating therapy. In some cases, PCH has been reported to develop with other disorders including connective tissue disease; however, to date, no reports have described PCH in a patient with rheumatoid arthritis. We report a case of a 59-year-old male PCH patient with rheumatoid arthritis and associated pulmonary fibrosis. He was initially diagnosed with severe group 3 PH and received sildenafil, which generated a favorable hemodynamic response. However, 5 years later, his pulmonary hemodynamics deteriorated, and he died at the age of 67. An autopsy was performed, and thickening of alveolar septa and capillary proliferation, pathological features of PCH, were extensively observed in both lungs. We discuss when PCH developed, how sildenafil improved his hemodynamics, and how PCH could be clinically detected by noninvasive evaluations.

Rapid disease progress in a PVOD patient carrying a novel EIF2AK4 mutation: a case report

Background

Pulmonary veno-occlusive disease (PVOD) and pulmonary arterial hypertension (PAH) share an overlapping disease phenotype. Hence it is necessary to distinguish them.

Case presentation

Our 14-year-old female patient admitted with progressive shortness of breath, dizziness, and fatigue even after minimal physical activity was clinically suspected for PAH, based on her previous history. Her chest computed tomography artery reported the presence of PVOD triad features - subpleural thickened septal lines, ground-glass nodules/opacities and mediastinal lymphadenopathy. Because of her weak physical stature, a lung biopsy was not performed; however, the genetic testing identified a novel heterozygous EIF2AK4 mutation at c.4833_4836dup (p.Q1613Kfs*10) - the dominant susceptible factor driving PVOD. Combination of genetic testing and computed tomography artery facilitated us to distinguish PVOD from PAH. Her disease symptoms advanced aggressively so that she died even before the lung transplantation, which was less than 6 months from the onset of disease symptoms.

Conclusion

This case report highlights that novel EIF2AK4 mutation at [c.4833_4836dup (p.Q1613Kfs*10)] would predict an aggressive phenotype of PVOD. Hence, we conclude that a genetic test identifying EIF2AK4 mutation would serve as a tool for the early diagnosis of PVOD, circumventing lung biopsy.

Pulmonary capillary hemangiomatosis in Chinese patients without EIF2AK4 mutations

BACKGROUND

Pulmonary capillary hemangiomatosis (PCH) is a very rare and refractory pulmonary vascular disease that causes pulmonary hypertension. Differentiation of PCH from idiopathic pulmonary arterial hypertension (iPAH) is essential because treatment and prognosis can vary greatly between these two diseases.

CASE PRESENTATION

A 20-year-old female and a 33-year-old male both presented with progressive exertional dyspnea and cough. High-resolution computed tomography (HRCT) showed bilateral, diffuse, ill-defined centrilobular nodules of ground-glass opacity, without subpleural thickened septal lines or mediastinal lymphadenopathy. Both cases showed clinical and imaging features characteristic of pulmonary veno-occlusive disease (PVOD) or PCH. The entire EIF2AK4 coding sequence was detected with Sanger sequencing, and no pathogenic EIF2AK4 mutations were identified in either case. Video-assisted thoracoscopic surgery (VATS) was safely performed in both cases, and histopathological examinations of biopsies showed that both patients had PCH.

CONCLUSION

Two patients presented with clinical and imaging characteristics suspicious for PVOD/PCH. Despite having no pathogenic EIF2AK4 mutations, both were diagnosed with PCH by VATS lung biopsies. The diagnostic distinction of PCH is important to prompt timely evaluations of patients who may need lung transplantations.

Pulmonary veno-occlusive disease: a probably underdiagnosed cause of pulmonary hypertension in systemic sclerosis

Pulmonary hypertension is a serious complication of systemic sclerosis and remains one of the leading causes of mortality. Pulmonary veno-occlusive disease (PVOD), recently reclassified as pulmonary arterial hypertension (PAH) with overt features of venous/capillaries involvement, is a subgroup of group 1 pulmonary hypertension, which has been rarely reported in systemic sclerosis patients. It is symptomatically indistinguishable from idiopathic pulmonary arterial hypertension and should be suspected in those with manifestations of pulmonary arterial hypertension who have evidence of pulmonary venous congestion in the absence of left-sided heart disease. Thoracic high-resolution computed tomography can give important hints for the diagnosis, such as ground-glass opacities/nodules, mediastinal lymph node enlargement and interlobular septal thickening. Patients with PVOD usually have a poor prognosis and might experience acute pulmonary oedema after introduction of pulmonary vasodilators. Due to clinical similarities between scleroderma-related PAH and PVOD, some patients are misdiagnosed and this could explain, in part, the worse prognosis associated with this clinical condition, when compared with idiopathic PAH. We report the case of a 72-year-old woman with limited systemic sclerosis, who was initially diagnosed with systemic sclerosis-related pulmonary arterial hypertension. However, after introduction of sildenafil and bosentan, the patient developed acute pulmonary oedema, and findings from complementary exams were suggestive of PVOD.

Targeted therapy in pulmonary veno-occlusive disease: time for a rethink?

Background

Pulmonary veno-occlusive disease (PVOD) is a rare condition with poor prognosis, and lung transplantation is recommended as the only curative therapy. The role of pulmonary arterial hypertension targeted therapy in PVOD remains controversial, and long-term effects of targeted therapy have been rarely reported. This study aims to retrospectively evaluate the role of targeted therapy in PVOD patients and the long-term outcome.

Methods

PVOD patients with good responses to targeted therapies were analyzed, and data pre- and post- targeted therapies were compared. An overview of the effects of targeted therapies on PVOD patients was also conducted.

Results

Five genetically or histologically confirmed PVOD patients received targeted therapies and showed good responses. Their mean pulmonary arterial pressure by right heart catheterization was 62.0 ± 11.7 mmHg. Two receiving monotherapy got stabilized, and three receiving sequential combination therapy got improved, cardiac function and exercise capacity significantly improved after treatments. No pulmonary edema occurred. The mean time from the first targeted therapy to the last follow up was 39.3 months, and the longest was 9 years. A systematic review regarding the effects of targeted therapies on PVOD patients indicated majorities of patients got hemodynamics or 6-min walk distance improved, and 26.7% patients developed pulmonary edema. The interval from targeted drugs use to death ranged from 71 min to over 4 years.

Conclusions

Cautious use of targeted therapy could safely and effectively improve or stabilize hemodynamics and exercise capacity of some patients without any complications. PVOD patients could live longer than expected.

Pulmonary capillary hemangiomatosis: a lesson learned

Pulmonary capillary hemangiomatosis (PCH) is a rare and controversial entity that is known to be a cause of pulmonary hypertension and is microscopically characterized by proliferation of dilated capillary-sized channels along and in the alveolar walls. Clinically, it is mostly seen in adults. Clinical features are characterized by nonspecific findings such as shortness of breath, cough, chest pain, and fatigue. It can be clinically indistinguishable from pre-capillary pulmonary arterial hypertension disorders such as primary pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension. However, the diagnostic distinction, which usually requires a multidisciplinary approach, is crucial in order to avoid inappropriate treatment with vasodilator medications usually used for PAH treatment. Prognosis of PCH remains poor with lung transplant being the only definitive treatment. We report an autopsy case of pulmonary capillary hemangiomatosis unmasked at autopsy that was treated with a prostacyclin analog, usually contraindicated in such patients. We emphasize that this entity should always be on the differential diagnosis in a patient with pulmonary hypertension and requires great vigilance on the part of the clinician, radiologist and pathologist to make the diagnosis and guide appropriate management.

Unique wreath-like smooth muscle proliferation of the pulmonary vasculature in pulmonary veno-occlusive disease versus pulmonary arterial hypertension

BACKGROUND/PURPOSE

Pulmonary veno-occlusive disease (PVOD) is a rare but fatal cause of pulmonary hypertension reported to be linked to mutations of eukaryotic initiation factor 2 alpha kinase 4 (EIF2AK4), also known as general control nonderepressible 2 kinase (GCN2). PVOD is difficult to diagnose and often initially misdiagnosed as other types of idiopathic pulmonary arterial hypertension (IPAH). To rapidly and correctly identify PVOD patients and explore the possible pathogenesis, we thoroughly investigated histopathological features and GCN2 protein levels in non-PAH, PVOD and PAH patients.

METHODS

Lung specimens were examined for histopathological changes, including those of pulmonary arteries and veins, by Masson's trichrome, modified Verhoeff's and α-SMA staining in the PVOD, IPAH, and non-PAH groups. GCN2 and α-SMA expression in lung tissue was examined by immunohistochemistry and western blotting.

RESULTS

PVOD and IPAH patients showed significant intimal and medial thickening of muscular pulmonary arteries compared with non-PAH patients. PVOD patients had more prominent intimal and medial thickening of muscular pulmonary veins than the other two groups. Interestingly, specialized muscle bundles surrounding the tunica adventitia of the pulmonary artery and vein were observed in PVOD patients. A significant decrease in GCN2 expression in the PVOD group was confirmed by immunohistochemistry and western blotting.

CONCLUSION

Our study is the first to show remarkable histological structures, including the wreath-like arrangement of a hyperplastic muscle bundle in the adventitia of pulmonary arteries, in PVOD patients as a diagnostic clue and to disclose the biological difference between PAH and PVOD in a Taiwanese population.

Idiopathic, heritable and veno-occlusive pulmonary arterial hypertension in childhood: computed tomography angiography features in the initial assessment of the disease

BACKGROUND

In children, idiopathic and heritable pulmonary arterial hypertension present echocardiographic and heart catheterization findings similar to findings in pulmonary veno-occlusive disease.

OBJECTIVE

To provide a systematic analysis of CT angiography anomalies in children with idiopathic or heritable pulmonary arterial hypertension, or pulmonary veno-occlusive disease. We also sought to identify correlations between CT findings and patients' baseline characteristics.

MATERIALS AND METHODS

We retrospectively analyzed CT features of children with idiopathic and heritable pulmonary arterial hypertension or pulmonary veno-occlusive disease and 30 age-matched controls between 2008 and 2014. We compared CT findings and patient characteristics, including gene mutation type, and disease outcome until 2017.

RESULTS

The pulmonary arterial hypertension group included idiopathic (n=15) and heritable pulmonary arterial hypertension (n=11) and pulmonary veno-occlusive disease (n=4). Median age was 6.5 years. Children with pulmonary arterial hypertension showed enlargement of pulmonary artery and right cardiac chambers. A threshold for the ratio between the pulmonary artery and the ascending aorta of ≥1.2 had a sensitivity of 90% and a specificity of 100% for pulmonary arterial hypertension. All children with pulmonary veno-occlusive disease had thickened interlobular septa, centrilobular ground-glass opacities, and lymphadenopathy. In children with idiopathic and heritable pulmonary arterial hypertension, presence of intrapulmonary neovessels and enlargement of the right atrium were correlated with higher mean pulmonary artery pressure (P=0.011) and pulmonary vascular resistance (P=0.038), respectively. Mediastinal lymphadenopathy was associated with disease worsening within the first 2 years of follow-up (P=0.024).

CONCLUSION

CT angiography could contribute to early diagnosis and prediction of severity in children with pulmonary arterial hypertension.

Co-existence of vocal cord dysfunction with pulmonary conditions other than asthma: A case series

Background

Vocal cord dysfunction (VCD) is defined as inappropriate movement of the vocal cords resulting in functional airway obstruction and symptoms including cough, wheezing, and dyspnea. VCD is often misdiagnosed with asthma but can also co-exist with asthma. The association of VCD with other serious pulmonary conditions has not been described to date.

Case reports

We describe the first case series of two adult patients evaluated at a university asthma clinic who in addition to having VCD also had significant pulmonary pathology other than asthma. Patient 1 had VCD and pulmonary veno-occulsive disease which necessitated a lung transplant. Patient 2 had VCD and a patent ductus arteriosis who necessitated surgical closure.

Conclusion

It is important to recognize that VCD can exist with pulmonary conditions other than asthma. Lack of improvement in respiratory symptoms after appropriate treatment for VCD should alert the clinician to evaluate for additional conditions.

Key technical steps in dual-pathway repair of congenital pulmonary vein stenosis

We present the case of a 2-year-old girl with congenital stenosis of the left inferior pulmonary vein associated with a large perimembranous ventricular septal defect. The child underwent repair of the left inferior pulmonary vein with autologous left atrial appendage as a pedicled tube, followed by closure of the ventricular septal defect. Important technical steps to minimize the restenosis rate are highlighted.

[Clinical and imaging features of pulmonary veno-occlusive disease and pulmonary capillary hemangioma]

Objective: To improve the diagnosis and treatment of the pulmonary veno-occlusive disease (PVOD) and pulmonary capillary hemangioma (PCH). Methods: The clinical features, radiological findings, laboratory testing and treatment in 8 cases of PVOD/PCH which was diagnosed from 2013 to 2017 were described. Results: PVOD/PCH was rare. The clinical symptoms were easily confused with IPAH, but the decrease of hypoxemia, clubbing, D(L)CO were more obvious, and the imaging features of HRCT were helpful for PVOD/PCH diagnosis. Combined with gene testing, it was helpful to diagnose PVOD/PCH and avoid the risk of surgical biopsy. Conclusion: PVOD and PCH are rare type of pulmonary vascular diseases. According to clinical manifestations, physical examination, pulmonary function test results, HRCT imaging, CPET and gene detection results, PVOD or PCH can be diagnosed.

Respiratory effects of trichloroethylene

Trichloroethylene (TCE) is a chlorinated solvent that has been used widely around the world in the twentieth century for metal degreasing and dry cleaning. Although TCE displays general toxicity and is classified as a human carcinogen, the association between TCE exposure and respiratory disorders are conflicting. In this review we aimed to systematically evaluate the current evidence for the respiratory effects of TCE exposure and the implications for the practicing clinician. There is limited evidence of an increased risk of lung cancer associated with TCE exposure based on animal and human data. However, the effect of other chlorinated solvents and mixed solvent exposure should be further investigated. Limited data are available to support an association between TCE exposure and respiratory tract disorders such as asthma, chronic bronchitis, or rhinitis. The most consistent data is the association of TCE with autoimmune and vascular diseases such as systemic sclerosis and pulmonary veno-occlusive disease. Although recent data are reassuring regarding the absence of an increased lung cancer risk with TCE exposure, clinicians should be aware of other potential respiratory effects of TCE. In particular, occupational exposure to TCE has been linked to less common conditions such as systemic sclerosis and pulmonary veno-occlusive disease.

Pulmonary veno-occlusive disease: An important consideration in patients with pulmonary hypertension

Pulmonary veno-occlusive disease is a rare subcategory of pulmonary arterial hypertension (WHO Group 1). The disease is poorly understood and difficult to diagnose; it has no definitive cure to date. These patients present with nonspecific symptoms, including dyspnea, exercise intolerance, and weakness. Chest x-rays sometimes differ from idiopathic pulmonary arterial hypertension and may demonstrate alveolar infiltrates and pleural effusions. High resolution computed tomography scans reveal ground glass opacities, interlobular septal thickening, and lymphadenopathy. Echocardiography can estimate the level of pulmonary artery pressures; right heart catheterization is needed for complete hemodynamic characterization of these patients. Lung biopsies demonstrate remodeling of the venules and small veins with intimal and adventitial fibrosis. This can result in total venous occlusion and subsequent recanalization. Similar changes occur in the small arteries and arterioles but are less pronounced than the venous changes. There is no effective medical therapy for these patients, and treatment with the pulmonary arterial hypertension specific medications often causes acute deterioration with pulmonary edema. The recent discovery of the biallelic mutations of the EIF2AK4 gene as an etiology for heritable form of pulmonary veno-occlusive disease increases our understanding of the disease pathogenesis and potentially identifies a future approach to treatment. Without definitive treatment, the prognosis is very poor, and the life expectancy of these patients is much shorter than patients with pulmonary arterial hypertension. These patients need early referral to transplantation centers.

Rapidly progressive pulmonary veno-occlusive disease in an infant with Down syndrome

A 4-month-old girl with Down syndrome showed unexpected deterioration of pulmonary hypertension. Despite aggressive pulmonary vasodilation therapy, the patient died at 5 months of age. Lung autopsy showed that the pulmonary veins were obliterated by intimal fibrous thickening, and the media of the veins was arterialised with an increase in elastic fibres. Pulmonary veno-occlusive disease should be considered in the management of individuals with Down syndrome.

A diffuse lung emphysema, severe pulmonary hypertension and lack of airflow limitation

Pulmonary veno-occlusive disease is characterized by remodeling of pulmonary arteries, capillaries and venules. We report a case of diffuse lung emphysema and pulmonary veno-occlusive disease with the characteristic of having no airflow limitation. A very low diffusing capacity for carbon monoxide and results of high-resolution computed tomography of the chest suggested pulmonary veno-occlusive disease. The diagnosis was confirmed on histological analysis after lung transplantation. The combination of results of the computed tomography of the chest and the histological analysis suggested a relationship between diffuse lung emphysema and remodeling of pulmonary vessels. A distinctive pattern of mild-to-moderate airflow limitation in patients with chronic obstructive pulmonary disease and severe pulmonary hypertension has been described. This observation of the combination of diffuse emphysema, pulmonary veno-occlusive disease and no airflow limitation supports further pathophysiological studies on severe pulmonary hypertension in chronic obstructive pulmonary disease.

Vasoproliferative process resembling pulmonary capillary hemangiomatosis in a cat

BACKGROUND

Pulmonary capillary hemangiomatosis is a rare, vascular obstructive disorder that uniformly causes pulmonary arterial hypertension. Clinically, pulmonary capillary hemangiomatosis is indistinguishable from primary pulmonary arterial hypertension and histology is required for definitive diagnosis. The distinctive histologic feature of pulmonary capillary hemangiomatosis is non-malignant extensive proliferation of capillaries in the alveolar septae. Vasodilator treatment of humans with primary arterial hypertension due to pulmonary capillary hemangiomatosis can result in fatal acute pulmonary edema. Computed tomography is thus critical to discern pulmonary capillary hemangiomatosis from other causes of pulmonary arterial hypertension prior to vasodilator therapy. This is the first report of a vasoproliferative process resembling pulmonary capillary hemangiomatosis in the feline species.

CASE PRESENTATION

A 15-year-old, male castrated, domestic shorthair cat presented for persistent labored breathing presumptively due to congestive heart failure despite treatment with diuretics for 7 days. Echocardiography showed evidence of hypertrophic cardiomyopathy with severe pulmonary hypertension; however, a normal sized left atrium was not consistent with congestive heart failure. Thoracic computed tomography was performed and showed evidence of diffuse ill-defined nodular ground glass opacities, enlarged pulmonary arteries, and filling defects consistent with pulmonary thromboembolism. The cat acutely decompensated after a single dose of sildenafil and was euthanized. Histopathology of the lungs showed severe multifocal alveolar capillary proliferation with respiratory bronchiolar infiltration, marked type II pneumocyte hyperplasia and multifocal pulmonary arterial thrombosis.

CONCLUSION

This is the first description in a cat of a vasoproliferative disorder resembling pulmonary capillary hemangiomatosis complicated by multifocal pulmonary arterial thrombosis. Inspiratory and expiratory ventilator-driven breath holds with angiography revealed lesions predominantly characterized by ground glass opacification and vascular filling defects with absence of air trapping. The results from this report suggest that, as in humans, the cat can develop a pulmonary capillary hemangiomatosis-like disease in which vasodilator therapy to address pulmonary hypertension may lead to fatal pulmonary edema.

Sorafenib as a potential strategy for refractory pulmonary arterial hypertension

Sorafenib is an inhibitor of multi-kinases including tyrosine and serine/threonine kinases. We investigated the efficacy and safety of sorafenib for the treatment of patients with refractory pulmonary arterial hypertension (PAH). Sorafenib was started in 9 patients (7 with idiopathic PAH, 2 with pulmonary veno-occlusive disease) who had severe PAH and right heart failure, in spite of treatment with vasodilators specific for PAH. Sorafenib was started as an add-on therapy at a dose of 50 or 100 mg/day, and increased to 100-400 mg/day. New York Heart Association functional class improved in 8 patients and did not change in 1. Mean pulmonary arterial pressure improved in 6 patients (14-28% decrease) and did not apparently change in 2 (follow-up catheterization was not performed in 1 patient). The main adverse effects of sorafenib were skin reactions on the hands and feet, which appeared in 5 patients. They were tolerable in 4 patients, but discontinuation of sorafenib was needed in only 1 patient. In conclusion, sorafenib had favorable effects to improve symptoms and objective variables in patients with refractory PAH, with tolerable adverse events. Sorafenib is an alternative strategy for patients with refractory PAH.

Pulmonary veno-occlusive disease and pulmonary capillary hemangiomatosis

Pulmonary veno-occlusive disease is a rare cause of pulmonary hypertension which is part, together with pulmonary capillary hemangiomatosis, of the special designation (subgroup 1') within pulmonary hypertension group 1 in the latest classification of the pulmonary hypertension World Symposium. Recent discovery that gene mutations in eukaryotic translation initiation factor 2 alpha kinase 4 (EIF2AK4) are responsible for inherited forms of pulmonary veno-occlusive disease has changed the role of genetic testing, acquiring relevant importance in the diagnosis of these patients. Despite the advances in genetic, cellular and molecular basis knowledge in the last decade, pulmonary veno-occlusive disease remains as a rare aetiology of pulmonary hypertension without any effective medical treatment approved and poor outcomes. This document aims to review the advances occurred in the understanding of pulmonary veno-occlusive disease in the last years.

Pulmonary veno-occlusive disease: Two children with gradual disease progression

Pulmonary veno-occlusive disease and pulmonary capillary hemangiomatosis are rare forms of pulmonary vascular disease. We report two cases of affected children who had evidence of pulmonary hypertension 3–5 years before developing radiographic findings of pulmonary veno-occlusive disease or pulmonary capillary hemangiomatosis. Both patients experienced a moderate decrease in pulmonary arterial pressure during acute vasodilator testing. Both patients experienced an improvement in six-minute walk performance without an increase in pulmonary edema when treated with targeted therapy for pulmonary hypertension. In some patients, pulmonary veno-occlusive disease and pulmonary capillary hemangiomatosis may progress slowly over a period of months to years. A favorable acute vasodilator response may identify patients who will tolerate, and demonstrate transient clinical improvement with, medical therapy.

EIF2AK4 mutation as "second hit" in hereditary pulmonary arterial hypertension

Background

Mutations in the eukaryotic translation initiation factor 2α kinase 4 (EIF2AK4) gene have recently been identified in recessively inherited veno-occlusive disease. In this study we assessed if EIF2AK4 mutations occur also in a family with autosomal dominantly inherited pulmonary arterial hypertension (HPAH) and incomplete penetrance of bone morphogenic protein receptor 2 (BMPR2) mutations.

Methods

Clinical examinations in a family with 10 members included physical examination, electrocardiogram, (stress)-echocardiography and lung function. Manifest PAH was confirmed by right heart catheterisation in three affected subjects. Genetic analysis was performed using a new PAH-specific gene panel analysis with next generation sequencing of all known PAH and further candidate genes. Identified variants were confirmed by Sanger sequencing.

Results

All living family members with manifest HPAH carried two pathogenic heterozygous mutations: a frame shift mutation in the BMPR2 gene and a novel splice site mutation in the EIF2AK4 gene. Two family members who carried the BMPR2 mutation only did not develop manifest HPAH.

Conclusions

This is the first study suggesting that EIF2AK4 can also contribute to autosomal dominantly inherited HPAH. Up to now it has only been identified in a recessive form of HPAH. Only those family members with a co-occurrence of two mutations developed manifest HPAH. Thus, the EIF2AK4 and BMRPR2 mutations support the “second hit” hypothesis explaining the variable penetrance of HPAH in this family. Hence, the assessment of all known PAH genes in families with a known mutation might assist in predictions about the clinical manifestation in so far non-affected mutation carriers.

Pulmonary hypertension secondary to pulmonary veno-occlusive disease complicated by right heart failure, hypotension and acute kidney injury

Pulmonary veno-occlusive disease (PVOD) is rare condition which can lead to severe pulmonary hypertension, right ventricular dysfunction, and cardiopulmonary failure. The diagnosis of PVOD can be challenging due to its nonspecific symptoms and its similarity to idiopathic pulmonary arterial hypertension and interstitial lung disease in terms of diagnostic findings. This case describes a 57 year old female patient who presented with a 5-month history of progressive dyspnea on exertion and nonproductive cough. Workup at another hospital was nonspecific and the patient underwent surgical lung biopsy due to concern for interstitial lung disease. She subsequently became hemodynamically unstable and was transferred to our hospital where she presented with severe hypoxemia, hypotension, and suprasystemic pulmonary artery pressures. Preliminary lung biopsy results suggested idiopathic pulmonary arterial hypertension and the patient was started on vasodilating agents, including continuous epoprostenol infusion. Pulmonary artery pressures decreased but remained suprasystemic and the patient did not improve. Final review of the biopsy by a specialized laboratory revealed a diagnosis of PVOD after which vasodilating therapy was immediately weaned off. Evaluation for dual heart-lung transplantation was begun. The patient's hospital course was complicated by hypotension requiring vasopressors, worsening right ventricular dysfunction, and acute kidney injury. During the transplantation evaluation, the patient decided that she did not want to undergo continued attempts at stabilization of her progressive multi-organ dysfunction and she was transitioned to comfort care. She expired hours after removing inotropic support.

Pulmonary hypertension after hematopoietic stem cell transplantation

Pulmonary hypertension (PH) is a potentially fatal complication of hematopoietic stem cell transplantation (HSCT). Given its nonspecific clinical presentation, it is likely that this clinical entity is underdiagnosed after HSCT. Data describing the incidence, risk factors, and etiology of PH in HSCT recipients are minimal. Physicians caring for HSCT recipients should be aware of this severe post-transplant complication because timely diagnosis and treatment may allow improved clinical outcomes. We summarize the pathophysiology, clinical presentation, diagnosis, and management of PH in HSCT recipients.

Pulmonary veno-occlusive disease in a female gardener

Pulmonary veno-occlusive disease (PVOD) is a subgroup of pulmonary arterial hypertension with a poor prognosis. The diagnosis is usually delayed and treatment options other than lung transplantation are unfortunately limited. We report the case of 51-year-old female gardener diagnosed with PVOD by open lung biopsy before her death. Although there are many reported cases of hepatic veno-occlusive disease due to toxic agents present in nature, such as pyrrolizidine alkaloid exposure, to date this has not been linked to PVOD.

Pulmonary hypertension associated with veno-occlusive disease in systemic sclerosis: Insight into the mechanism of resistance to vasodilator

We report a case with pulmonary veno-occlusive disease (PVOD) associated with systemic sclerosis which exhibits strong resistance to pulmonary vasodilator. A 55-year-old female with severe pulmonary hypertension was admitted to our hospital to be introduced to epoprostenol infusion therapy. She was diagnosed as having pulmonary arterial hypertension (PAH) associated with systemic sclerosis at the age of 51. Several aggressive treatments with pulmonary vasodilators, including oral prostaglandin, endothelin receptor antagonists, and phosphodiesterase 5 inhibitors, failed to improve her symptoms. We introduced continuous intravenous epoprostenol therapy from 2 μg/kg/min for her. However, pulmonary edema appeared and worsened in a dose-dependent manner. We made a diagnosis of PVOD clinically at that time. Thereafter, pulmonary edema gradually disappeared consistent with the reduction of the dose of epoprostenol infusion. She died of renal failure and infection 4 months after the introduction of epoprostenol infusion therapy. A histological examination revealed severe stenosis and occlusions of pulmonary veins as well as pulmonary arteries over a wide area. We suggest that prevalence of veno-occlusive type of disease could be one of the major mechanisms of less responsive or even refractory to pulmonary vasodilator therapies in patients with PAH associated with connective tissue disease.

Pulmonary hypertension associated with bone marrow transplantation

Bone marrow transplantation (BMT) is one of the promising methods of treatment of hematologic malignancy. However, it has a variety of complications since it involves fatal doses of anti-cancer drugs and radiation during the conditioning period. Among the various complications of BMT, pulmonary hypertension is rare and its pathogenesis is poorly understood. A 35-year-old female with acute myeloid leukemia (AML) presented with pulmonary hypertension after BMT. Although she exhibited severe dyspnea on admission, her general condition markedly improved after oxygen therapy and treatment with warfarin and beraprost sodium. Her pulmonary hypertension was diagnosed as pulmonary arterial hypertension (PAH) related to BMT. Although PAH has only rarely been reported as a complication of BMT, we present here for the first time an adult patient with PAH associated with BMT who exhibited marked improvement with medical treatment. This case indicates that attention needs to be paid to the clinical symptoms and physical findings of PAH as a complication of BMT.