Primary pulmonary hypertension. The risk and benefit of lung biopsy

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.

Pulmonary Veno-occlusive Disease: A Surgical Lung Biopsy-proven and Autopsied Case Radiologically Mimicking Hypersensitivity Pneumonitis at the Time of a Transbronchial Lung Biopsy

Pulmonary veno-occlusive disease (PVOD) is a rare disease in the subgroup of conditions known as pulmonary arterial hypertension. Although a histological examination is needed for a definitive diagnosis, a non-invasive diagnosis is required for patients with pulmonary hypertension because a lung biopsy is deemed risky. We herein report a 32-year-old woman diagnosed with PVOD via a surgical lung biopsy and autopsy whose disease showed radiological findings mimicking those of hypersensitivity pneumonitis (pneumonia) at the time of the transbronchial lung biopsy, without obvious pulmonary hypertension on admission. When clinicians encounter patients with interstitial lung disease, they should not forget the possibility of PVOD and should be alert for emerging pulmonary hypertension.

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.

Pulmonary Hypertension and Cancer: Etiology, Diagnosis, and Management

OPINION STATEMENT

Pulmonary hypertension is caused by cancer and its therapeutic agents including chemotherapy, radiotherapy, and even the targeted therapies. Ironically, some of the cancer therapies that cause one type of pulmonary hypertension (PH) could potentially be employed in the treatment of another PH type. Greater awareness on the role of cancer therapeutic agents in causing PH is required. Conversely, since PH is mostly incurable, the potential role of some of these cancer therapeutic agents in the cure of PH should be recognized. In short, the relationship between cancer, cancer therapy, and PH is an interesting one requiring further attention, education, and research.

Chemotherapy-induced pulmonary hypertension: role of alkylating agents

Pulmonary veno-occlusive disease (PVOD) is an uncommon form of pulmonary hypertension (PH) characterized by progressive obstruction of small pulmonary veins and a dismal prognosis. Limited case series have reported a possible association between different chemotherapeutic agents and PVOD. We evaluated the relationship between chemotherapeutic agents and PVOD. Cases of chemotherapy-induced PVOD from the French PH network and literature were reviewed. Consequences of chemotherapy exposure on the pulmonary vasculature and hemodynamics were investigated in three different animal models (mouse, rat, and rabbit). Thirty-seven cases of chemotherapy-associated PVOD were identified in the French PH network and systematic literature analysis. Exposure to alkylating agents was observed in 83.8% of cases, mostly represented by cyclophosphamide (43.2%). In three different animal models, cyclophosphamide was able to induce PH on the basis of hemodynamic, morphological, and biological parameters. In these models, histopathological assessment confirmed significant pulmonary venous involvement highly suggestive of PVOD. Together, clinical data and animal models demonstrated a plausible cause-effect relationship between alkylating agents and PVOD. Clinicians should be aware of this uncommon, but severe, pulmonary vascular complication of alkylating agents.

Saudi guidelines on the diagnosis and treatment of pulmonary hypertension: 2014 updates

The Saudi Association for Pulmonary Hypertension (previously called Saudi Advisory Group for Pulmonary Hypertension) has published the first Saudi Guidelines on Diagnosis and Treatment of Pulmonary Arterial Hypertension back in 2008.[1] That guideline was very detailed and extensive and reviewed most aspects of pulmonary hypertension (PH). One of the disadvantages of such detailed guidelines is the difficulty that some of the readers who just want to get a quick guidance or looking for a specific piece of information might face.

All efforts were made to develop this guideline in an easy-to-read form, making it very handy and helpful to clinicians dealing with PH patients to select the best management strategies for the typical patient suffering from a specific condition. This Guideline was designed to provide recommendations for problems frequently encountered by practicing clinicians involved in management of PH. This publication targets mainly adult and pediatric PH-treating physicians, but can also be used by other physicians interested in PH.

In vivo assessment of pulmonary arterial wall fibrosis by intravascular optical coherence tomography in pulmonary arterial hypertension: a new prognostic marker of adverse clinical follow-up

Background:

The aim is to correlate pulmonary arterial (PA) remodeling estimated by PA fibrosis in PA hypertension (PAH) with clinical follow-up. Histology of PA specimens is also performed.

Methods:

19 patients, aged 54±16 (4 men), functional class II-III were studied with right heart catheterization, PA Intravascular Ultrasound and optical coherence tomography (OCT) in inferior lobe segment. PA wall fibrosis was obtained by OCT ( area of fibrosis/PA cross sectional area × 100). Patients follow-up was blind to OCT. Events were defined as mortality, lung transplantation, need of intravenous prostaglandins or onset of right ventricular failure.

Results:

OCT measurements showed high intra- and interobserver agreement. There was a good correlation between OCT and histology in PA fibrosis from explanted lungs. Area of fibrosis was 1.4±0.8 mm², % fibrosis was 22.3±8. Follow-up was 3.5 years (2.5-4.5). OCT %Fib was significantly correlated with PA capacitance (r=-0.536) and with pulmonary vascular rsistance (r=0.55). Patients were divided according to the median value of PA fibrosis. There were 10 patients with a high (≥ 22%) and 9 with a low fibrosis (<22%). Events occurred in 6 (1 death, 1 lung transplantation, 2 intravenous prostaglandins, 2 right heart failure) out of 10 patients with high and in 0 out of 9 patients with low fibrosis (p<0.01).

Conclusions:

In PAH, the severity of PA remodeling assessed by OCT wall fibrosis was significantly predictive of severely unfavorable clinical outcome. In vivo assessment of pulmonary arterial wall fibrosis by intravascular OCT in PAH is a promising new prognostic marker of adverse clinical outcome.

Pulmonary veno-occlusive disease: the bête noire of pulmonary hypertension in connective tissue diseases?

Pulmonary veno-occlusive disease (PVOD) is a rare form of pulmonary hypertension that may develop in patients with connective tissue diseases (CTD). Most cases have been reported in patients with systemic sclerosis, though associations with systemic lupus erythematosis and mixed connective tissue disease have also been described. PVOD is characterised by progressive obstruction of small pulmonary veins and venules that leads to increased pulmonary vascular resistance, right heart failure and premature death. Distinguishing PVOD from pulmonary arterial hypertension (PAH) is often difficult, though use of a diagnostic algorithm may improve diagnostic accuracy and preclude recourse to lung biopsy. The finding of normal left-heart filling pressures in the context of radiological studies suggestive of pulmonary oedema is an important diagnostic clue, particularly if this clinical scenario coincides with the introduction of vasodilator therapy. There are no approved treatments for the disorder, though cautious use of PAH specific therapy may improve short-term outcomes in selected idiopathic PVOD cases. This review summarises the epidemiologic, clinico-pathologic and imaging characteristics of PVOD in the setting of CTD and discusses potential management approaches.

Pulmonary veno-occlusive disease: clinical, functional, radiologic, and hemodynamic characteristics and outcome of 24 cases confirmed by histology

Pulmonary veno-occlusive disease (PVOD) is defined by specific pathologic changes of the pulmonary veins. A definite diagnosis of PVOD thus requires a lung biopsy or pathologic examination of pulmonary explants or postmortem lung samples. However, lung biopsy is hazardous in patients with severe pulmonary hypertension, and there is a need for noninvasive diagnostic tools in this patient population. Patients with PVOD may be refractory to pulmonary arterial hypertension (PAH)-specific therapy and may even deteriorate with it. It is important to identify such patients as soon as possible, because they should be treated cautiously and considered for lung transplantation if eligible. High-resolution computed tomography of the chest can suggest PVOD in the setting of pulmonary hypertension when it shows nodular ground-glass opacities, septal lines, lymph node enlargement, and pleural effusion. Similarly, occult alveolar hemorrhage found on bronchoalveolar lavage in patients with pulmonary hypertension is associated with PVOD. We conducted the current study to identify additional clinical, functional, and hemodynamic characteristics of PVOD. We retrospectively reviewed 48 cases of severe pulmonary hypertension: 24 patients with histologic evidence of PVOD and 24 randomly selected patients with idiopathic, familial, or anorexigen-associated PAH and no evidence of PVOD after meticulous lung pathologic evaluation. We compared clinical and radiologic findings, pulmonary function, and hemodynamics at presentation, as well as outcomes after the initiation of PAH therapy in both groups. Compared to PAH, PVOD was characterized by a higher male:female ratio and higher tobacco exposure (p < 0.01). Clinical presentation was similar except for a lower body mass index (p < 0.02) in patients with PVOD. At baseline, PVOD patients had significantly lower partial pressure of arterial oxygen (PaO2), diffusing lung capacity of carbon monoxide/alveolar volume (DLCO/VA), and oxygen saturation nadir during the 6-minute walk test (all p < 0.01). Hemodynamic parameters showed a lower mean systemic arterial pressure (p < 0.01) and right atrial pressure (p < 0.05), but no difference in pulmonary capillary wedge pressure. Four bone morphogenetic protein receptor II (BMPR2) mutations have been previously described in PVOD patients; in the current study we describe 2 additional cases of BMPR2 mutation in PVOD. Computed tomography of the chest revealed nodular and ground-glass opacities, septal lines, and lymph node enlargement more frequently in patients with PVOD compared with patients with PAH (all p < 0.05). Among the 16 PVOD patients who received PAH-specific therapy, 7 (43.8%) developed pulmonary edema (mostly with continuous intravenous epoprostenol, but also with oral bosentan and oral calcium channel blockers) at a median of 9 days after treatment initiation. Acute vasodilator testing with nitric oxide and clinical, functional, or hemodynamic characteristics were not predictive of the subsequent occurrence of pulmonary edema on treatment. Clinical outcomes of PVOD patients were worse than those of PAH patients.

Surgical biopsy: its appropriateness in diagnosing interstitial lung disease

PURPOSE OF REVIEW

Our goal is to update advances in the use of surgical lung biopsy in the idiopathic interstitial pneumonias. We discuss an approach for identifying patients with idiopathic interstitial pneumonias who may benefit from surgical lung biopsy, newer surgical approaches and complications and risks of surgery.

RECENT FINDINGS

A consensus statement on idiopathic interstitial pneumonias has described the natural history and response to therapy of idiopathic interstitial pneumonias. The statement discussed selection of patients with idiopathic interstitial pneumonias for surgical lung biopsy and avoidance of unneeded biopsy, particularly for patients with 'classical' radiographic findings of idiopathic pulmonary fibrosis. Video-assisted thoracoscopic lung biopsy continues to be the standard procedure for surgical lung biopsy. Newer approaches have used outpatient surgery for selected patients, earlier removal of chest tubes and modifications of surgical technique. At-risk patients include those with respiratory failure, rapid progression of disease, pulmonary hypertension and advanced disease.

SUMMARY

Standard video-assisted thoracoscopic lung biopsy should be considered in patients with interstitial lung diseases of unknown cause who have a subacute course, ground-glass opacities on high-resolution computed tomography or features atypical for idiopathic pulmonary fibrosis, as these patients may respond to therapy. A step-wise process for selection of patients for surgical lung biopsy is recommended.

Screening, early detection, and diagnosis of pulmonary arterial hypertension: ACCP evidence-based clinical practice guidelines

Pulmonary arterial hypertension (PAH) occurs as an idiopathic process or as a component of a variety of disease processes, including chronic thromboembolic disease, connective tissue diseases, congenital heart disease, and exposure to exogenous factors including appetite suppressants or infectious agents such as HIV. This article reviews evidence for screening in susceptible patient groups and the approach to diagnosing PAH when it is suspected, and provides specific recommendations for applying this evidence to clinical practice.

Acute pulmonary edema caused by epoprostenol infusion in a child with scimitar syndrome and pulmonary hypertension

INTRODUCTION

Intravenous epoprostenol is frequently administered in adults and children for treatment of pulmonary hypertension. Although generally safe, pulmonary edema has been described in a few case reports of adult patients with pulmonary veno-occlusive disease.

CASE REPORT

We present an infant who had an operation for scimitar syndrome and abnormal drainage of the right pulmonary veins into the inferior vena cava who developed pulmonary edema while receiving a prostacyclin infusion. The typical partial anomalous pulmonary venous drainage was operatively corrected at 6 days of age, and an accompanying coarctation was resected. At 7 months of age, diagnostic cardiac catheterization was performed to evaluate suspected pulmonary hypertension. Pulmonary pressure was elevated to supra-systemic values, and obstructed venous drainage of the right hypoplastic lung was demonstrated. To decrease pulmonary hypertension during weaning and extubation, epoprostenol infusion was initiated. Sixty minutes after extubation, massive acute pulmonary edema lead to reintubation. Mean airway pressure of 16 mm Hg (21 mbar) with pure oxygen ventilation was initially required, with an oxygenation index of 14, a ventilation index of 36, and an alveolar-arterial oxygen tension difference of 541 mm Hg. After discontinuation of epoprostenol, weaning and extubation was successful.

CONCLUSION

Pulmonary edema caused by prostacyclin infusion in patients with impaired postcapillary pulmonary drainage may also be encountered in children and has to be anticipated.

The inadvisability of thoracoscopic lung biopsy on patients with pulmonary hypertension

The use of video-assisted thoracoscopic surgery (VATS) sometimes leads to additional and unnecessary risks compared with thoracotomy. We report a troubling case of VATS lung biopsy in a 43-year-old woman with mild pulmonary hypertension. A progressive elevation of pulmonary artery pressure (PAP) was noted after the commencement of right unilateral ventilation. When the systolic PAP reached 90 mm Hg (390 min after induction of anesthesia), a massive blood discharge through the chest drain occurred. At repeat thoracotomy, continuous blood spouting was seen from > 10 of the surgical sites. It was supposed that the endoscopic staplers were unable to maintain hemostasis with such a high PAP.

High-resolution CT of the chest in four patients with pulmonary capillary hemangiomatosis or pulmonary venoocclusive disease

OBJECTIVE

Clinical differentiation of isolated pulmonary hypertensive arteriopathy from pulmonary capillary hemangiomatosis or pulmonary venoocclusive disease can be difficult on a clinical basis alone. Differentiation is important because misdiagnosis of pulmonary capillary hemangiomatosis or pulmonary venoocclusive disease may lead to severe vasodilator-induced pulmonary edema. The objective of our study was to determine whether high-resolution CT of the chest could distinguish pulmonary capillary hemangiomatosis or pulmonary venoocclusive disease from isolated pulmonary hypertensive arteriopathy.

CONCLUSION

Pulmonary hypertension in patients who also have pulmonary capillary hemangiomatosis or pulmonary venoocclusive disease shows characteristics on high-resolution CT that are not seen in patients with isolated pulmonary hypertensive arteriopathy.

Pulmonary edema complicating continuous intravenous prostacyclin in pulmonary capillary hemangiomatosis

Continuous intravenous epoprostenol (prostacyclin) produces hemodynamic and symptomatic responses and improves survival in patients with severe primary pulmonary hypertension refractory to conventional medical therapy. However, it has been recently shown that short-term infusion of epoprostenol can produce pulmonary edema in pulmonary veno-occlusive disease, presumably because of increased pulmonary perfusion in the presence of downstream vascular obstruction. We describe two additional cases of pulmonary edema complicating continuous intravenous epoprostenol in patients displaying severe pulmonary hypertension and pulmonary capillary hemangiomatosis, a rare condition characterized by the proliferation of thin-walled microvessels in the alveolar walls. This report indicates that epoprostenol therapy should not be used in patients with severe pulmonary hypertension secondary to pulmonary capillary hemangiomatosis.

Primary plexogenic pulmonary hypertension shows imperfect formation of the internal elastic lamina of the pulmonary arteries

Lung tissue from subjects dying from primary plexogenic pulmonary hypertension (PPH) has shown defects of elastin formation of the lung arteries. Lung vessels from 5 cases of PPH were compared with those of 9 age-matched normal subjects, and 24 individuals having secondary pulmonary hypertension (2 degrees PH). PPH cases and those with 2 degrees PH due to congenital heart disease with left-to-right shunts (2 degrees PH, LRS), showed active proliferation of medial smooth muscle cells (SMC) through defects of the internal elastic lamina (IEL) into the arterial lumen to form typical plexiform lesions. Larger arteries showed accelerated intimal thickening similar to normal aging. Plexiform lesions were not seen in normal subjects or in those developing high pulmonary pressures later in life. The observations showed that the development of discontinuities of the IEL of the pulmonary arteries and intimal thickening is accelerated in normal subjects by high pulmonary artery pressure, especially when this is established at a very young age. They suggest that such discontinuities occur in PPH due to inherent abnormality of the elastin of the arterial walls, with advanced early proliferation of medial SMC and obstruction of the pulmonary arterial circulation.

Thrombotic lesions in primary plexogenic arteriopathy. Similar pathogenesis or complication?

In 78 patients with primary plexogenic arteriopathy (PPA), numbers of organized and recanalized thrombi were established in histologic slides of lung tissue and expressed per square centimeter of section. Three control groups of ten individuals each were used: normal, plexogenic arteriopathy secondary to ventricular septal defect, and hypoxic pulmonary hypertension. Thrombotic lesions were scarce in normal individuals but numerous in all three groups with pulmonary hypertension. There is also a positive correlation with age. Thrombotic lesions are absent or scarce in children but more common in adults, even in normal control subjects and particularly in pulmonary hypertension by whatever cause. In PPA there is likely to be a relation with the duration of illness but not with the stage of the disease. The complete pattern of plexogenic arteriopathy may develop in the absence of thrombotic lesions, which clearly are not essential for its pathogenesis. Rather than being part specifically of PPA, as sometimes suggested, thrombotic lesions complicate various types of hypertensive pulmonary vascular disease. Apparently the combination of sustained pulmonary hypertension and age, possibly through endothelial injury, may elicit thrombosis and its sequelae, which in turn may aggravate the pulmonary arterial pressure.