[Genetic diagnostics and molecular approaches in pulmonary arterial hypertension]. / Genetische Diagnostik und molekulare Ansätze bei pulmonalarterieller Hypertonie.

The recently published new European guidelines for diagnosis and treatment of pulmonary hypertension now offer the so far most extensive description of genetic testing and counselling for pulmonary arterial hypertension patients. In addition, the importance of a clinical screening of healthy mutation carriers is highlighted as well as the genetic testing of patients with a suspicion of pulmonary veno-occlusive disease. We frame the respective parts of the guidelines on genetic testing and counselling in the context of recent data and provide comments. Finally, we give an outlook on novel molecular approaches starting from Sotatercept, addressing ion channels and novel therapeutic developments.

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.

Recanalization of a Chronic Total Pulmonary Vein Occlusion Occurring after Transcatheter Atrial Fibrillation Ablation.

Pulmonary vein occlusion (PVO) is a known complication of radiofrequency ablation for atrial fibrillation. We present a case with delayed presentation leading to chronic total PVO. Computed Tomography (CT) imaging did not predict the presence of residual flow. Despite this, the occlusion was successfully stented using wire escalation techniques adapted from chronic total occlusion coronary angioplasty, with resolution of symptoms. This emphasises the importance of combining CT with invasive angiography for patient selection and interventional strategy. Innovative angioplasty techniques used to overcome PVO need to be balanced against additional risk of perforation when dealing with extra-cardiac structures.

Pulmonary Veno-occlusive Disease that Developed Following Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia.

We herein report a case of pulmonary veno-occlusive disease (PVOD) induced by allo-hematopoietic stem cell transplantation (HSCT) in a 48-year-old man who was diagnosed with acute myeloid leukemia. Five months after transplantation, he developed dyspnea and was diagnosed with pulmonary hypertension based on right heart catheterization. Although he received treatment with pulmonary vasodilators, diuretics, and corticosteroids, his pulmonary artery pressure did not decrease, and his pulmonary edema worsened. Based on the clinical course, hypoxemia, diffusion impairment, and computed tomography findings, the patient was diagnosed with HSCT-related PVOD. Critical attention should be paid to dyspnea after HSCT for the early diagnosis of PVOD.

Patient-specific and gene-corrected induced pluripotent stem cell-derived endothelial cells elucidate single-cell phenotype of pulmonary veno-occlusive disease.

Pulmonary veno-occlusive disease (PVOD) is a rare form of pulmonary hypertension characterized by the preferential remodeling of the pulmonary venules. Hereditary PVOD is caused by biallelic variants of the EIF2AK4 gene. Three PVOD patients who carried the compound heterozygous variants of EIF2AK4 and two healthy controls were recruited and induced pluripotent stem cells (iPSCs) were generated from human peripheral blood mononuclear cells (PBMCs). The EIF2AK4 c.2965C>T variant (PVOD#1), c.3460A>T variant (PVOD#2), and c.4832_4833insAAAG variant (PVOD#3) were corrected by CRISPR-Cas9 in PVOD-iPSCs to generate isogenic controls and gene-corrected-iPSCs (GC-iPSCs). PVOD-iPSC-endothelial cells (ECs) exhibited a decrease in GCN2 protein and mRNA expression when compared with control and GC-ECs. PVOD-ECs exhibited an abnormal EC phenotype featured by excessive proliferation and angiogenesis. The abnormal phenotype of PVOD-ECs was normalized by protein kinase B inhibitors AZD5363 and MK2206. These findings help elucidate the underlying molecular mechanism of PVOD in humans and to identify promising therapeutic drugs for treating the disease.

Veno-occlusive disease of the lung after allogeneic haematopoietic stem-cell transplantation: An autopsy study.

Pulmonary veno-occlusive disease (pVOD) is a potentially life-threatening sequela of allogeneic haematopoietic stem-cell transplantation (alloHSCT). We conducted a morphometric evaluation of autopsy lung tissue to determine the incidence of pVOD and its association with donor type, conditioning regime, hepatic sinusoidal obstruction syndrome (hSOS), survival time, and graft versus host disease (GvHD). The degree of occlusion of pulmonary veins in 78 autopsy cases after alloHSCT and 12 control cases was assigned to one of the following categories: none, minor thickening of the intima (up to 33% narrowing), moderate pVOD wherein about half of the lumen (34-66%) is occluded, or advanced pVOD with near total or total (67-100%) obliteration of the lumen. Minor thickening of the intima was found in all patients after alloHSCT (median: 66% of the vessels) and it was found to a lesser extent in the control cases (median: 12%). Moderate to advanced pVOD was seen in 95% of the cases, but only in a minority of the veins and venules (median: 6% of the veins and venules). PVOD was not significantly correlated with other histopathological findings within the lungs, including acute pneumonia, desquamative pneumonia, acute respiratory distress syndrome, organising and non-specific pneumonia, and bronchiolitis obliterans or acute lung disease. PVOD was significantly associated with a conditioning regimen including cyclophosphamide, fludarabine, or antithymocyte globulin and the duration of survival after alloHSCT. It was not associated with acute or chronic GvHD, other intestinal lung diseases, hSOS, or donor characteristics. PVOD was found in most patients after they underwent alloHSCT, although it mainly involved only a minority of the vessels. It was associated with the conditioning regime and the duration of survival after alloHSCT.

[Familial pulmonary veno-occlusive disease with a composite biallelic heterozygous EIF2AK4 mutation]. / Une maladie veino-occlusive pulmonaire familiale avec mutation biallélique hétérozygote composite d'EIF2AK4.

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 capillary haemangiomatosis: a distinct entity?

Pulmonary capillary haemangiomatosis (PCH) is a rare and incompletely understood histopathological finding characterised by abnormal capillary proliferation within the alveolar interstitium, which has long been noted to share many overlapping features with pulmonary veno-occlusive disease (PVOD). But are PCH and PVOD distinct entities that occur in isolation, or are they closely intertwined manifestations along a spectrum of the same disease? The classic clinical features of both PCH and PVOD include signs and symptoms related to pulmonary hypertension, hypoxaemia, markedly impaired diffusion capacity of the lung and abnormal chest imaging with ground glass opacities, septal lines and lymphadenopathy. In recent years, increasing evidence suggests that the clinical presentation, histopathological features, genetic substrate and pathobiological mechanisms of PCH and PVOD are overlapping and usually indistinguishable. The discovery of biallelic mutations in the eukaryotic translation initiation factor 2 α kinase 4 (EIF2AK4) gene in heritable PCH and PVOD greatly advanced our understanding of the overlapping nature of these conditions. Furthermore, recognition of PCH and PVOD-like changes in other pulmonary vascular diseases and in conditions that cause chronic pulmonary venous hyper-perfusion or hypertension suggests that PCH/PVOD may develop as a reactive process to various insults or injuries to the pulmonary vasculature, rather than being primary angiogenic disorders.

Venoocclusive Disease With Both Hepatic and Pulmonary Involvement.

Pulmonary venoocclusive disease (PVOD) is a rare form of pulmonary vascular disease with pulmonary hypertension characterized by preferential involvement of the pulmonary venous system. Hepatic venoocclusive disease (HVOD), also known as sinusoidal obstruction syndrome, is a condition that occurs in 13% to 15% of patients after hematopoietic stem cell transplantation (HSCT). Although hepatic and pulmonary venoocclusive diseases may share some pathologic features as well as some etiologies such as HSCT, these two disorders have never been described together in a single adult patient. We report the case of a patient who received HSCT and developed HVOD and PVOD within 9 months. Despite their differences, PVOD and HVOD share common risk factors and associated conditions, suggesting that in the context of HSCT, the two diseases share common pathophysiological mechanisms. Optimal treatment for HSCT-related PVOD remains to be determined.

Recurrent pulmonary vein stenosis after successful intervention: Prognosis and management of restenosis.

OBJECTIVES: The aim of this study was to describe management of recurrent pulmonary vein stenosis (PVS) and determine if stenting is superior to balloon angioplasty (BA) in preventing subsequent restenosis. BACKGROUND: PVS is a serious complication of atrial fibrillation ablation. BA and stenting are effective therapies; however, restenosis frequently occurs. Here we report management of recurrent stenosis. METHODS: This was a prospective observational study performed from 2000 to 2014. RESULTS: One hundred and thirteen patients with severe PVS underwent intervention in 88 veins treated with BA and 81 treated with stenting. Forty-two patients experienced restenosis. Restenosis was more common in veins treated with BA (RRR 53% [95% CI 32-70%, p = .008]). A second intervention was performed in 41 patients. In the 34 vessels treated with initial BA, 24 were treated for restenosis with a stent and 10 were treated with a second BA. The recurrence rate was 46% in those treated with BA followed by stenting and 50% in those treated with two BA procedures. In the 22 veins treated with initial stenting, 9 were treated with another stent and 13 were treated with BA. The recurrence rate was 44% in those treated with a second stent and 46% for those treated with a stent followed by BA. The risk of a third stenosis was the same among all groups (Analysis of variance [ANOVA] p = .99). Limited sample size precluded analysis of outcome by stent size. CONCLUSIONS: Restenosis occurred in 44% of patients overall. Management is challenging; stenting does not appear to be superior to BA.

Long-term outcome of percutaneous intervention for pulmonary vein stenosis after pulmonary vein isolation procedure.

OBJECTIVES: Report long-term outcomes of percutaneous intervention in patients with pulmonary vein stenosis (PVS) after pulmonary vein isolation (PVI) from a single center over 16 years. BACKGROUND: Outcome reports of percutaneous intervention for PVS resulting from PVI are limited. METHODS: Retrospective review of all patients with PVS after PVI who underwent percutaneous intervention at the Cleveland Clinic Foundation between January 2000 and December 2016. RESULTS: A total of 205 patients underwent cardiac catheterization for PVS during the study period. Completely occluded veins which could not be recanalized occurred in six patients. Of the remaining 199 patients, 27 (14%) were lost to follow-up, leaving 172 patients with 276 veins for analysis. Balloon angioplasty was performed in 62 veins and stent implantation in 250 (primary in 214, to treat postdilation restenosis in 36). Re-intervention occurred in 45/62 (73%) balloon-dilated veins and 45/250 (18%) stented veins. Freedom from re-intervention at 1 and 5 years was 90 and 73% following stenting versus 40 and 23% following balloon dilation (p < .001, Hazard ratio (HR) = 5.7). Veins with stent diameter ≥7 mm (n = 231) had greater freedom from re-intervention (95% at 1 year, 79% at 5 years) than veins with stents <7 mm (43% at 1 year, 9% at 5 years), p < .001. There was clear symptomatic improvement after intervention and no procedural mortality. CONCLUSIONS: Stent implantation at ≥7 mm for PVS after PVI is associated with low rates of re-intervention, in contrast to balloon dilation and stenting with small conventional stents.

Real-time three-dimensional trans-oesophageal echocardiography-guided balloon dilation of pulmonary venous pathway obstruction in a patient with dextro-transposition of the great arteries after atrial switch surgery: a case report.

A percutaneous transcatheter balloon dilation of a pulmonary venous pathway obstruction was successfully performed in a 40-year-old patient after a Mustard procedure. During the procedure, real-time three-dimensional trans-oesophageal echocardiography demonstrated the morphology of the obstruction. Our case highlights the usefulness of real-time three-dimensional trans-oesophageal echocardiography as a guide for transcatheter intervention in the increasing number of adults with CHD.

Understanding the Similarities and Differences between Hepatic and Pulmonary Veno-Occlusive Disease.

Hepatic veno-occlusive disease (HVOD), alias sinusoidal obstruction syndrome, may develop as a complication of chemotherapy in the setting of hematopoietic stem cell transplantation. HVOD is less frequently described after exposure to chemotherapy in the nontransplant setting and can also be a complication after ingestion of toxins, such as pyrrolizidine alkaloids. Veno-occlusive disease may also affect the lungs, and it is therefore termed pulmonary veno-occlusive disease (PVOD). Similarly, PVOD can develop after exposure to chemotherapeutic agents in the treatment of solid and hematological malignancies. In addition, PVOD has also been linked to autoimmune disorders and occupational solvent exposure. Finally, the heritable form of PVOD is due to biallelic mutations of the EIF2AK4 gene. Both HVOD and PVOD share common histopathological features and pathophysiologic mechanisms. Both clinical disorders are rare complications that can appear after exposure to the common inciting trigger of chemotherapeutic agents. The present review aims to summarize the current knowledge of HVOD and PVOD and to describe both similarities as well as differences regarding both conditions.

Catheter based treatments for fibrosing mediastinitis.

Fibrosing mediastinitis is a rare, often debilitating and potentially lethal disease characterized by an exuberant fibroinflammatory response within the mediastinum. Patients typically present with insidious symptoms related to compression of adjacent structures including the esophagus, heart, airways, and cardiac vessels. Fibrosing mediastinitis is most often triggered by Histoplasmosis infection; however, antifungal and anti-inflammatory therapies are largely ineffective. While structural interventions aimed at alleviating obstruction can provide significant palliation, surgical interventions are challenging with high mortality and clinical experience with percutaneous interventions is limited. Here, we will review the presentation, natural history, and treatment of fibrosing mediastinitis, placing particular emphasis on catheter-based therapies.

Intraluminal Pulmonary Vein Stenosis in Children: A "New" Lesion.

Pulmonary vein stenosis (PVS) is a rare disorder that leads to progressive narrowing of the extrapulmonary veins. PVS has been reported in both children and adults and in its worse iteration leads to pulmonary hypertension, right ventricular failure, and death. Multiple etiologies of PVS have been described in children and adults. This review will focus on intraluminal PVS in children. Intraluminal PVS has an estimated incidence ranging from 0.0017% to 0.03%. It is associated with conditions such as prematurity, bronchopulmonary dysplasia, necrotizing enterocolitis, Smith-Lemli-Opitz syndrome, and Down syndrome. Cardiac catheterization and pulmonary vein angiography are the gold standard for diagnosis and anatomic delineation. Other imaging modalities including magnetic resonance imaging, chest tomography, and transesophageal echocardiography are increasingly being used. Mortality of PVS in children is approximately 50%. Predictors of mortality include involvement of ≥3 pulmonary veins, bilateral pulmonary vein involvement, onset of PVS in infancy, elevated pulmonary artery pressure or systolic pulmonary artery-to-aortic pressure ratio, right ventricular dysfunction, restenosis after surgery, distal/upstream disease, and disease progression to previously uninvolved pulmonary veins. Treatment includes catheter-based pulmonary vein dilations with or without stenting, surgical interventions, medical therapy, and in some instances, lung transplantation. Cardiac catheterization for PVS involves a comprehensive hemodynamic and anatomic assessment of the pulmonary veins as well as therapeutic transcatheter interventions. Several surgical strategies have been used. Sutureless repair is currently most commonly used, but patch venoplasty, endarterectomy, ostial resection, and reimplantation are used in select circumstances as well. Medical therapies such as imatinib mesylate and bevacizumab are increasingly being used in an effort to suppress the myofibroblastic proliferation seen in PVS patients. Lung transplantation has been used as an alternative treatment strategy for end-stage, refractory PVS. Nonetheless, despite the different innovative approaches used, morbidity and mortality remain high. At present, the preferred treatment strategy is frequent reassessment of disease progression to guide use of catheter-based and surgical interventions in conjunction with medical therapy.