Pulmonary Capillary Hemangiomatosis and Pulmonary Veno-occlusive Disease

Pulmonary Capillary Hemangiomatosis as a Rare Underlying Cause of Primary Pulmonary Hypertension: A Case Report in an Adolescent

Despite its rarity, pulmonary capillary hemangiomatosis (PCH) presents a significant diagnostic challenge. Due to its similarity to other pulmonary vascular diseases, such as pulmonary veno-occlusive disease, it is characterized by abnormal pulmonary capillary proliferation, which is a rare cause of primary pulmonary hypertension. This case was the first reported instance of PCH in Shahid Rajaee Heart Hospital in Tehran, Iran, in 2023, which was confirmed by genetic testing. It highlighted the importance of considering PCH among the differential diagnoses for pulmonary hypertension, even in adolescent patients. The 13-year-old patient's main complaints were progressive exertional dyspnea and chest pain. He had no previous medical history and had not taken any pharmaceutical or herbal medications. Critical clinical findings included a heart murmur, an electrocardiogram revealing right ventricular hypertrophy, and echocardiogram evidence of pulmonary hypertension. The main diagnosis was PCH, as shown by CT findings of pulmonary artery dilatation and diffuse nodular ground glass opacities. Genetic tests indicated pathogenic EIF2AK4 mutations and suspicion of PCH. Therapeutic intervention included vasodilator therapy, which exacerbated the patient's condition. This case emphasized the importance of maintaining a high index of suspicion for rare causes of pulmonary hypertension, such as PCH. The outcome was to prepare the patient for lung transplantation. To differentiate PCH from other pulmonary vascular diseases, a combination of clinical presentation, radiologic studies, genetic analysis, and response to treatment is required to determine appropriate management, particularly lung transplantation.

Pulmonary veno-occlusive disease in Sjogren's syndrome: a case report

BACKGROUND

Pulmonary arterial hypertension (PAH) associated with connective tissue disease (CTD) belongs to Group 1 pulmonary hypertension. Pulmonary veno-occlusive disease (PVOD), which is characterized by venous system aberrations, has been previously reported in CTD-PAH; however, it has rarely been observed in Sjogren's syndrome (SS).

CASE PRESENTATION

Our 28-year-old female patient was admitted to the hospital with recurrent shortness of breath even after minimal physical activity. Her chest high-resolution CT scan demonstrated pulmonary artery dilatation and bilateral ground-glass nodules. A subsequent right heart catheterization confirmed pulmonary hypertension because her mean pulmonary arterial pressure was 62 mmHg. Our inquisitive genomic assessment identified a novel EIF2AK4 mutation at c.1021 C > T (p. Gln341*), the dominant causal gene of PVOD. Histological examination demonstrated stenosis and occlusions in the pulmonary veins. Because she presented with features such as dry eyes and Raynaud's phenomenon, we performed a biopsy on the labial salivary gland, which confirmed SS. Her treatment regimen included PAH-targeted therapies (tadalafil and macitentan) in combination with hydroxychloroquine. Although she was hospitalized several times due to acute exacerbation of PAH, her disease progression was under control, and she did not demonstrate any signs of pulmonary edema even after a three-year treatment period.

CONCLUSION

Here, we report the case of an SS-PAH patient with PVOD who carried a novel biallelic EIF2AK4 mutation, and PAH-targeted therapies were well tolerated by our patient.

Case report: Rescue treatment with add-on selexipag in a preterm infant with suprasystemic pulmonary hypertension, pulmonary capillary hemangiomatosis, and isolated pulmonary vein stenosis

An extremely dystrophic, premature female infant, born at 25 3/7 weeks of gestational age (birth weight: 430 g) with severe pulmonary hypertension (PH), was admitted to our neonatal intensive care unit (ICU) requiring cardiorespiratory support, including mechanical ventilation and pulmonary vasodilators such as inhaled nitric oxide (iNO) and continuous intravenous sildenafil infusions. The diagnosis of bronchopulmonary dysplasia (BPD) was made. A hemodynamically relevant, persistent ductus arteriosus (PDA) was surgically ligated after failed pharmacologic PDA closure using indomethacin and ibuprofen. The patient was discharged with an estimated 2/3 systemic pulmonary artery pressure. One month after hospital discharge, on low-flow oxygen supplementation (0.5 L/min FiO2 100%), at the corrected age of 16 weeks, she was readmitted to our emergency department with signs of respiratory distress and circulatory decompensation. Echocardiography demonstrated suprasystemic PH. Severe PH persisted despite initiated invasive mechanical ventilation, triple vasodilating therapy [iNO, macitentan, and continuous intravenous (IV) sildenafil], as well as levosimendan, milrinone, and norepinephrine for recompensation from cardiac shock. Thus, we started off-label oral selexipag therapy (oral IP receptor agonist) in the smallest patient reported so far (4 kg body weight). Subsequently, RV systolic pressure decreased to half-systemic, allowing successful weaning of iNO, norepinephrine, and milrinone, and extubation of the patient over 4 days. The infant was discharged 4 weeks after pediatric intensive care unit (PICU) admission in stable cardiorespiratory condition, with an oral, specific, triple antihypertensive PAH-targeted therapy using selexipag, macitentan, and sildenafil as well as oxygen therapy at low-flow (0.5 l/min) and spironolactone. The first cardiac catheterization at the age of 9 months under aforementioned triple PAH-targeted therapy revealed mild PH with 35% systemic PA pressure (mPAP/mSAP = 0.35) and isolated pulmonary vein stenosis. A transthoracic biopsy at the age of 12 months confirmed the diagnosis of BPD and further showed pulmonary interstitial glycogenosis and severe pulmonary capillary hemangiomatosis, without involvement of the pulmonary venules (chILD A2, A3, and B4 according to the Deutsch-Classification). The patient is currently in stable cardiorespiratory condition undergoing triple PH-targeted therapy including selexipag. This report highlights the potential benefits of the oral prostacyclin mimetic selexipag as an early add-on PH-targeted drug in chronic PH of infancy (cPHi).

Computed tomography of pulmonary veins: review of congenital and acquired pathologies

Newer-generation CT scanners with ultrawide detectors or dual sources offer millisecond image acquisition times and significantly decreased radiation doses compared to historical cardiac CT and CT angiography. This technology is capable of nearly freezing cardiac and respiratory motion. As a result, CT is increasingly used for diagnosing and monitoring cardiac and vascular abnormalities in the pediatric population. CT is particularly useful in the setting of pulmonary vein evaluation because it offers evaluation of the entire pulmonary venous system and lung parenchyma. In this article we review a spectrum of congenital and acquired pulmonary venous abnormalities, including potential etiologies, CT imaging findings and important factors of preoperative planning. In addition, we discuss optimization of CT techniques for evaluating the pulmonary veins.

Feline pulmonary hypertension: are we overlooking an important comorbidity?

Pulmonary hypertension (PH) is a potential complication in many disease states, yet it has been largely overlooked in feline medicine. Recently, increased awareness of potential underlying causes has led to a wider understanding of the disease process in humans, with a focus on tailoring therapy to include specific treatment of the underlying etiology. Most of these treatments are not yet available in veterinary medicine, but as they move from the human to the veterinary field, it would be beneficial to better understand the forms of PH encountered in different species. Recently, diagnosis and classification of PH in dogs has been the focus of an American College of Veterinary Internal Medicine consensus statement, yet this condition has received little attention in cats. It is therefore our intention to raise awareness of this condition in cats and to propose a classification system for the types of PH seen in feline patients. As new medications are developed for the treatment of PH, it is important to recognize which forms of PH are seen in feline patients and understand the etiology of the disease. There are many reports of PH (or suspected PH based on echocardiographic assessment) in cats. In this review, we highlight the large number of conditions, and different etiologies, that are associated with PH. Improving understanding of this condition will bring us closer to being able to investigate the benefits of potential new diagnostics and therapies as they become available.

New progress in diagnosis and treatment of pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive disease. Although great progress has been made in its diagnosis and treatment in recent years, its mortality rate is still very significant. The pathophysiology and pathogenesis of PAH are complex and involve endothelial dysfunction, chronic inflammation, smooth muscle cell proliferation, pulmonary arteriole occlusion, antiapoptosis and pulmonary vascular remodeling. These factors will accelerate the progression of the disease, leading to poor prognosis. Therefore, accurate etiological diagnosis, treatment and prognosis judgment are particularly important. Here, we systematically review the pathophysiology, diagnosis, genetics, prognosis and treatment of PAH.

Solitary pulmonary capillary hemangioma mimicking a preinvasive malignant lesion in an asymptomatic middle-aged female patient

Pulmonary capillary hemangiomatosis (PCH) is a rare disease characterized by a proliferation of capillaries in the alveolar septa, bronchial and venous walls, pleura, and regional lymph nodes. However, the etiology of the disease remains unknown due to its rarity. Therefore, we present a case of a solitary PCH lesion without symptoms in a 38-year-old female patient. According to computed tomography, she was diagnosed with lung carcinoma, indicated by a tiny nodule with ground-glass opacity detected in her right upper lung. However, no other lesions were detected on systemic examination. Consequently, partial lung resection was conducted, since the lesion was suspected of lung adenocarcinoma. Pathologic results showed that the thick alveolar septa were caused by capillary growth without cellular atypia and hardly any infiltration of inflammatory cells. Finally, we diagnosed the pulmonary lesion as PCH, although solitary PCH has previously been reported in a few case reports. Therefore, further case studies are essential to clarify the causes of PCH.

Radiological Findings in Multidetector Computed Tomography (MDCT) of Hereditary and Sporadic Pulmonary Veno-Occlusive Disease: Certainties and Uncertainties

Pulmonary veno-occlusive disease (PVOD) is a very infrequent form of pulmonary arterial hypertension with an aggressive clinical course, poor response to specific vasodilator treatment, and low survival. Confirming a definitive diagnosis is essential to guide treatment and assess lung transplantation. However, in the absence of histological or genetic confirmation, the diagnosis is complex, requiring a clinical suspicion. Multidetector computed tomography (MDCT) is an essential part of the non-invasive diagnostic tools of PVOD. We retrospectively reviewed the MDCT findings from a consecutive series of 25 patients diagnosed with PVOD, 9 with the sporadic form and 16 with the hereditary form of the disease. The presence and extent of typical findings of the diagnostic triad were assessed in all patients (ground glass parenchymal involvement, septal lines, and lymphadenopathy). In our series, 92% of patients showed at least two of the radiological findings described as typical of the disease. All patients presented at least one typical radiological characteristic. The incidence of radiological findings considered typical is very high, however was not associated with greater hemodynamic severity nor to the development of acute lung edema. No significant differences were found between the two groups. A poorly expressive MDCT does not exclude the disease.

Genetics and Genomics of Pediatric Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a rare disease with high mortality despite recent therapeutic advances. The disease is caused by both genetic and environmental factors and likely gene-environment interactions. While PAH can manifest across the lifespan, pediatric-onset disease is particularly challenging because it is frequently associated with a more severe clinical course and comorbidities including lung/heart developmental anomalies. In light of these differences, it is perhaps not surprising that emerging data from genetic studies of pediatric-onset PAH indicate that the genetic basis is different than that of adults. There is a greater genetic burden in children, with rare genetic factors contributing to ~42% of pediatric-onset PAH compared to ~12.5% of adult-onset PAH. De novo variants are frequently associated with PAH in children and contribute to at least 15% of all pediatric cases. The standard of medical care for pediatric PAH patients is based on extrapolations from adult data. However, increased etiologic heterogeneity, poorer prognosis, and increased genetic burden for pediatric-onset PAH calls for a dedicated pediatric research agenda to improve molecular diagnosis and clinical management. A genomics-first approach will improve the understanding of pediatric PAH and how it is related to other rare pediatric genetic disorders.

Anesthesia for pulmonary veno-occlusive disease: the dilemma and what we should know as anesthesiologists: A case report

INTRODUCTION

Pulmonary veno-occlusive disease (PVOD) is a rare form of pulmonary hypertension. It is often underdiagnosed or misdiagnosed as idiopathic pulmonary arterial hypertension (PAH). Inappropriate treatment may cause worsening of symptoms which may lead to fatal outcomes. Anesthetic considerations and management for pulmonary hypertension are well described, but few anesthesiologists are aware of the entity of PVOD and its management.

PATIENT CONCERNS

We report a case of PVOD in a 73-year-old female who was on concurrent aspirin and anagrelide, requiring emergent open femoral hernia repair.

DIAGNOSIS

PVOD and incarcerated femoral hernia INTERVENTION:: Combined spinal-epidural (CSE) was performed to enable the surgery.

OUTCOME

Surgery was completed successfully under central neuraxial anesthesia and the patient remained stable and comfortable throughout, avoiding the need for general anesthesia. Due to the concurrent aspirin and anagrelide therapy, significant bleeding from the CSE puncture site was observed immediately post-operatively. This was resolved with external manual compression and withholding the aspirin and anagrelide. Patient remained well without neurological deficit and was discharged postoperative day seven.

LESSONS

It is important to differentiate PVOD from PAH due to the controversial use of pulmonary vasodilators in PVOD. Pulmonary vasodilator is commonly used to treat acute pulmonary hypertension in PAH but its usage may lead to pulmonary edema in patients with PVOD. Hence, with no ideal treatment available, the avoidance of general anesthesia is crucial to prevent acute pulmonary hypertensive crisis in patient with PVOD. However, this needs to be weighed against the elevated risk of central neuraxial bleeding when performing a CSE in a patient on concurrent aspirin and anagrelide therapy. Calculated decision-making considering the risks and benefits of all alternatives should be carried out in such a scenario, and measures should be taken in anticipation of the potential consequences of the eventual decision.

CONCLUSION

It is important to differentiate PVOD from PAH. PVOD has unique anesthetic considerations due to the controversial use of pulmonary vasodilators. This case also emphasizes the importance of active anticipation of potential issues and adequate follow up.

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

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

Novel EIF2AK4 mutations in histologically proven pulmonary capillary hemangiomatosis and hereditary pulmonary arterial hypertension

Background

Pulmonary hypertension (PH) remains one of the rarest and deadliest diseases. Pulmonary Capillary Hemangiomatosis (PCH) is one of the sub-classes of PH. It was identified using histological and molecular tools and is characterized by the proliferation of capillaries into the alveolar septae. Mutations in the gene encoding the eukaryotic translation initiation factor 2 alpha kinase 4 (EIF2AK4) have recently been linked to this particular subgroup of PH.

Methods

In our effort to unveil the genetic basis of idiopathic and familial cases of PH in Lebanon, we have used whole exome sequencing to document known and/or novel mutations in genes that could explain the underlying phenotype.

Results

We showed bi-allelic mutations in EIF2AK4 in two non-consanguineous families: a novel non-sense mutation c.1672C > T (p.Q558*) and a previously documented deletion c.560_564drlAAGAA (p.K187Rfs9*). Our histological analysis coupled with the CT-scan results showed that the two patients with the p.Q558* mutation have PH. In contrast, only one of the individuals harboring the p.K187Rfs9* variant has a documented PCH while his older brother remains asymtomatic. Differential analysis of the variants in the genes of the neighboring network of EIF2AK4 between the two siblings identified a couple of interesting missense mutations that could account for this discrepancy.

Conclusion

These findings represent a novel documentation of the involvement of EIF2AK4 in the different aspects of pulmonary hypertension. The absence of a molecular mechanism that relates the abrogated function of the protein to the phenotype is still a major hurdle in our understanding of the disease.

An Autopsy Case of Pulmonary Capillary Hemangiomatosis with an Electron Microscopy Study

BACKGROUND Pulmonary capillary hemangiomatosis (PCH) and pulmonary veno-occlusive disease (PVOD) are rare diseases that share clinical, X-ray, and histological features. Most patients have poor prognosis due to severe respiratory impairment. Recently, EIF2AK4 mutations were found in some patients with PCH and PVOD, but the role of this mutation is still unknown. We report an autopsy case of PCH and discuss a mechanism of respiratory dysfunction based on an electron microscopy study. CASE REPORT The patient was a Japanese man in his sixties. He suffered from acute exacerbation of dyspnea during treatment of COPD. Respiratory function testing revealed DLCO' 32.1% and DLCO'/VA 23.6%. Echocardiography demonstrated findings consistent with pulmonary hypertension. A CT scan showed mild emphysema and small ground-glass opacity in the lungs. However, we could not find the exact cause of his respiratory failure and he died 28 days after admission. At autopsy, the histology showed multilayering capillary proliferation within the alveolar walls. Electron microscopy examination revealed prominent widening of the air-blood barrier, scarce fusion of the epithelial and capillary basement membranes, and frequent narrowing of the capillary lumen. CONCLUSIONS We reported an autopsy case with PCH with no histological findings of PVOD. Whether PCH and PVOD are 2 different histological patterns of the same disease remains to be verified. The changes in the air-blood barrier detected by electron microscopy may explain the respiratory impairment and pulmonary arterial hypertension.

Novel Lung Biopsy Surgical Technique for Definitive Diagnosis of Pulmonary Capillary Hemangiomatosis

PURPOSE

The 2015 European Society of Cardiology/European Respiratory Society Guidelines for the Diagnosis and Treatment of Pulmonary Hypertension state that lung biopsy is still the gold standard for confirming pulmonary capillary hemangiomatosis; however, the surgical lung biopsy is no longer recommended in most cases for its inherent risks. Nonintubated and uniportal video-assisted thoracoscopic surgery are the new developments in video-assisted thoracoscopic surgery technology. We combined these 2 technologies to create a novel approach for pulmonary capillary hemangiomatosis lung biopsy.

DESCRIPTION

A incision is made in chest wall. Sponge forceps are used to pull the lung out of the pleural space, and to resect target lung tissue. The incised margin is sutured with 3-0 Prolene (Ethicon, Somerville, NJ), and a negative pressure suction tube is used to fully expand the lung.

EVALUATION

Three patients were definitively diagnosed with pulmonary capillary hemangiomatosis by this technology. One patient developed a postoperative fever, with no other complications.

CONCLUSIONS

The tubeless and uniportal video-assisted thoracoscopic surgery lung biopsy is a safe, effective, and feasible technology for definitively diagnosing patients with pulmonary capillary hemangiomatosis.

A case of early diagnosis of pulmonary capillary hemangiomatosis in a worker with exposure to silica

Background

Pulmonary capillary hemangiomatosis (PCH) is a progressive and refractory vascular disease in the lung. Pulmonary hypertension is frequently combined with PCH when capillary proliferation invades to nearby pulmonary vascular systems. It is difficult to differentiate PCH from other diseases such as pulmonary venoocclusive disease and pulmonary arterial hypertension that cause pulmonary hypertension as they frequently overlap.

Case presentation

A 29-year-old female who had worked at a bathtub factory presented with progressive exertional dyspnea for the past 2 years. Computed tomography revealed centrilobular, diffusely spreading ground-glass opacities sparing subpleural parenchyma with some cystic lesions and air-trapping in both lungs, suggesting a peculiar pattern of interstitial lung disease with airway involvement. There was not any evidence of right heart failure or pulmonary hypertension on echocardiogram, as well as radiography. Microscopic examination of the lung by thoracoscopic resection showed atypical proliferation of capillary channels within alveolar walls and interlobar septa, without invasion of large vessels.

Conclusion

We experienced a pathologically diagnosed PCH in a young female complaining progressive dyspnea with prior exposure to occupational silica or organic solvent without elevated right ventricular systolic pressure (RVSP) who showed atypical pattern of radiologic findings.

United States Pulmonary Hypertension Scientific Registry (USPHSR): rationale, design, and clinical implications

Diagnostic World Health Organization (WHO) Group 1 pulmonary arterial hypertension (PAH) and Diagnostic Group 1' pulmonary veno-occlusive disease (PVOD) and/or pulmonary capillary hemangiomatosis (PCH) are progressive and fatal disorders. Past registries provided important insights into these disorders, but did not include hormonal exposures or genomic data. The United States Pulmonary Hypertension Scientific Registry (USPHSR) will provide demographic, physiologic, anorexigen and hormone exposure, genomic, and survival data in the current therapeutic era for 499 patients diagnosed with PAH, PVOD, or PCH. The USPHSR also will explore the relationship between pharmacologic, non-pharmacologic, and dietary hormonal exposures and the increased risk for women to develop idiopathic or heritable PAH.

Pulmonary capillary hemangiomatosis: An unusual cause of primary pulmonary hypertension in a child with characteristic computed tomography imaging features

Pulmonary capillary hemangiomatosis (PCH) is a rare cause of primary pulmonary hypertension (PPH) diagnosed in children and young adults with a nonspecific clinical presentation of dyspnea, cough, chest pain, and fatigue. It is characterized by extensive proliferation of pulmonary capillaries within alveolar septa. The imaging features include diffuse centrilobular ground-glass opacities with features of pulmonary hypertension. We present a case of PCH in an 11-year-old boy who was diagnosed with PPH in echocardiography and referred for diagnostic imaging.

Pulmonary veno-occlusive disease as a cause of severe pulmonary hypertension in a dog

Background

Pulmonary veno-occlusive disease (PVOD) is a rare cause of pulmonary arterial hypertension (PAH) in humans and can be classified in idiopathic, heritable, drug and radiation-induced, and associated with connective tissue disease or human immunodeficiency virus infection. Recently, biallelic mutations of the EIF2AK4 gene have been discovered as a cause for an autosomal recessive form of PVOD in humans. In dogs, PAH is poorly characterized and is generally considered to be idiopathic or secondary to (for example) congenital left-to right cardiovascular shunts or heartworm disease. However, recently, the pathologic features resembling human PVOD were retrospectively described in post-mortem lung samples of dogs presenting with respiratory distress and idiopathic pulmonary hypertension (PH), which suggests that PVOD contributes to an unknown percentage of cases with unexplained PH. In dogs, information on the clinical presentation of PVOD is scarce and the cause and pathogenesis of this disease is still unknown.

Case presentation

An 11-year-old, intact male German Shepherd dog (GSD) was presented with a 2-day history of acute-onset dyspnea and generalized weakness. Physical examination, laboratory analysis, thoracic radiography, echocardiography, a computed tomography scan and an ante mortem lung biopsy demonstrated severe arterial hypoxemia and severe PH but were not diagnostic for a known disease syndrome. Based on the poor reaction to therapy with oxygen, sildenafil, pimobendan and dexamethasone the dog was euthanized. Histopathology of the lungs showed venous and arterial remodelling, segmental congestion of alveolar capillaries and foci of vascular changes similar to human pulmonary capillary hemangiomatosis, indicating that the dog suffered from PVOD. Whole genome sequencing analysis was performed on the case and a healthy GSD. Validation was performed by Sanger sequencing of five additional GSD's unknown for any form of respiratory stress and aged ≥ 10 years. No causal variants were found in the genes that are known to be involved in human PVOD and PAH.

Conclusions

This case report confirms that PVOD should be a diagnostic consideration in dogs presenting with dyspnea and unexplained PH. In the present case, no casual genetic mutations known to be involved in humans with PVOD and PAH were found.

Clinical features of canine pulmonary veno-occlusive disease and pulmonary capillary hemangiomatosis

Background

Histologic features of pulmonary veno‐occlusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH) have been described in dogs but without a thorough clinical description.

Objectives

To report the clinical features, diagnostics, treatment, and outcome of dogs with histologic evidence of PVOD and PCH.

Animals

Fifteen pet dogs meeting histopathologic criteria of PVOD (occlusive remodeling of small‐sized to medium‐sized pulmonary veins) or PCH (alveolar capillary proliferation and congestion), or both.

Methods

Medical records of dogs with PVOD and PCH identified based on histopathologic features between 2003 and 2017 were retrospectively reviewed.

Results

Fifteen dogs met inclusion criteria of a histologic diagnosis of PVOD or PCH or both. Dogs were older (median 11 years) with no apparent breed or sex predisposition. Dogs presented with acute clinical signs (median 3 days), usually respiratory distress. Thoracic radiography (available in 10 dogs) revealed right cardiomegaly and patchy or diffuse interstitial to alveolar patterns, with 9 dogs having a normal left cardiac silhouette. In 5 dogs tested, pulmonary arterial hypertension (PAH) was documented. In all 3 dogs, thoracic computed tomography scans showed pulmonary arterial enlargement and perivascular diffuse nodular ground‐glass opacities. Ten of 15 dogs died within 1 day; median survival was 3 days.

Conclusions and Clinical Importance

In dogs with PAH, the inability to document left‐sided congestive heart failure and failure to identify another cause of signs of respiratory disease should increase suspicion for PVOD and PCH. With increased awareness of PVOD and PCH by clinicians and pathologists, dogs with compatible clinicopathologic features should be evaluated for these pulmonary vascular disorders.

Pulmonary Arterial Hypertension

This article provides an overview of pulmonary arterial hypertension (PAH), beginning with the initial pathologic recognition of pulmonary hypertension more than 100 years ago and progressing to the current diagnostic categorization of PAH. It reviews the epidemiology, pathophysiology, genetics, and modern treatment of PAH. The article discusses several important recent studies that have highlighted the importance of new management strategies, including serial risk assessment and combination pharmacotherapy.

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.

A 63-Year-Old Woman With Neurofibromatosis Type 1 and Pulmonary Hypertension With Worsening Hypoxemia

CASE PRESENTATION

A 63-year-old woman with a history of neurofibromatosis type-1 (NF-1) and pulmonary arterial hypertension (PAH) thought to be secondary to the NF-1 presented with a few weeks of worsening dyspnea on exertion. She took no medications other than sildenafil for her pulmonary hypertension (PH). She denied tobacco, alcohol, and illicit or anorectic drug use. She had previously worked as a waitress. Her mother and her brother had NF-1 but no PH or lung disease.

Variable Expressivity of a Founder Mutation in the EIF2AK4 Gene in Hereditary Pulmonary Veno-occlusive Disease and Its Impact on Survival

INTRODUCTION AND OBJECTIVES

Hereditary pulmonary veno-occlusive disease (PVOD) has been associated with biallelic mutations in EIF2AK4 with the recent discovery of a founder mutation in Iberian Romani patients with familial PVOD. The aims of this study were phenotypical characterization and survival analysis of Iberian Romani patients with familial PVOD carrying the founder p.Pro1115Leu mutation in EIF2AK4, according to their tolerance to pulmonary vasodilators (PVD). Familial genetic screening was conducted, as well as assessment of sociocultural determinants with a potential influence on disease course.

METHODS

Observational study of Romani patients with familial PVOD included in the Spanish Registry of Pulmonary Arterial Hypertension. Genetic screening of EIF2AK4 was performed in index cases and relatives between November 2011 and July 2016 and histological pulmonary examination was carried out in patients who received a lung transplant or died. The patients were divided into 2 groups depending on their tolerance to PVD, with comparison of baseline characteristics and survival free of death or lung transplant.

RESULTS

Eighteen Romani patients were included: 9 index cases and 9 relatives. The biallelic founder mutation in EIF2AK4 was found in all affected cases and 2 unaffected relatives. Family screening showed 34.2% of healthy heterozygotes, high consanguinity, young age at childbirth, and frequent multiparity. Prognosis was bleak, with significant differences depending on tolerance to PVD.

CONCLUSIONS

We describe 2 phenotypes of hereditary PVOD depending on tolerance to PVD, with prognostic impact and familial distribution. Consanguinity may have a negative impact on the transmission of PVOD, with familial genetic screening showing high effectiveness.