"High probability" perfusion lung scans in pulmonary venoocclusive disease

Pulmonary veno-occlusive disease: illustrative cases and literature review

Pulmonary veno-occlusive disease (PVOD), also known as "pulmonary arterial hypertension (PAH) with overt features of venous/capillary involvement", is a rare cause of PAH characterised by substantial small pulmonary vein and capillary involvement, leading to increased pulmonary vascular resistance and right ventricular failure. Environmental risk factors have been associated with the development of PVOD, such as occupational exposure to organic solvents and chemotherapy, notably mitomycin. PVOD may also be associated with a mutation in the EIF2AK4 gene in heritable forms of disease. Distinguishing PVOD from PAH is critical for guiding appropriate management. Chest computed tomography typically displays interlobular septal thickening, ground-glass opacities and mediastinal lymphadenopathy. Life-threatening pulmonary oedema is a complication of pulmonary vasodilator therapy that can occur with any class of PAH drugs in PVOD. Early referral to a lung transplant centre is essential due to the poor response to therapy when compared with other forms of PAH. Histopathological analysis of lung explants reveals microvascular remodelling with typical fibrous veno-occlusive lesions. This review covers the main features distinguishing PVOD from PAH and two clinical cases that illustrate the challenges of PVOD management.

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.

A case of glucocorticoid-resistant adult Still's disease complicated by pulmonary hypertension and interstitial lung disease

Adult Still's disease (ASD) is rarely complicated by pulmonary hypertension (PH). A 76-year-old woman experienced ASD relapse with repeated exacerbation of PH and interstitial lung disease. Although she had been treated with immunosuppressive agents and pulmonary vasodilators, the ASD relapsed with fever, rash, increased inflammatory responses and exacerbated interstitial lung disease, and PH. The pathology of PH appeared to encompass groups 1 [pulmonary arterial hypertension (PAH)], 1' [pulmonary veno-occlusive disease (PVOD)], and 3. Remission induction therapy with high-dose glucocorticoid and tocilizumab was administered, and switching or adding pulmonary vasodilators was also attempted. As the disease activity of ASD decreased, the mean pulmonary arterial pressure and pulmonary vascular resistance improved. PH is an extremely rare form of organ dysfunction in individuals with ASD. Like other systemic autoimmune diseases, PH (PAH or PVOD) can determine the prognosis of ASD. Because of PH's rarity, it is important to sufficiently evaluate its pathology, considering the possibility that PH is not clinically classified as PAH (group 1), and to administer immunosuppressive therapy and vasodilators according to the pathology.

False Positive Ventilation/Perfusion SPECT/CT Mismatch Mimicking Pulmonary Embolism in a Patient With Bilateral Lung Transplant

ABSTRACT

Ventilation/perfusion SPECT/CT has very high sensitivity with little false-positive findings for diagnosing pulmonary embolism (PE). However, bronchopulmonary tumors or structural changes of the lungs' vasculature infrequently mimic PE. Here, a 59-year-old man presented with acute dyspnea and acute renal failure 5 years after bilateral lung transplant. Pulmonary ventilation/perfusion SPECT/CT was performed demonstrating a lobar mismatch of the left upper lung lobe indicative for PE. Bronchoscopy revealed local hyperemia of this lobe, indicating prolonged venous blood return. Subsequent CT angiography confirmed postsurgical upper pulmonary vein obliteration as final diagnosis. In conclusion, pulmonary vein obliteration might cause false-positive ventilation/perfusion SPECT/CT.

Dual-energy CT lung perfusion characteristics in pulmonary arterial hypertension (PAH) and pulmonary veno-occlusive disease and/or pulmonary capillary hemangiomatosis (PVOD/PCH): preliminary experience in 63 patients

BACKGROUND

In the stratification of potential causes of PH, current guidelines recommend performing V/Q lung scintigraphy to screen for CTEPH. The recognition of CTEPH is based on the identification of lung segments or sub-segments without perfusion but preserved ventilation. The presence of mismatched perfusion defects has also been described in a small proportion of idiopathic pulmonary arterial hypertension (PAH) and pulmonary veno-occlusive disease and/or pulmonary capillary hemangiomatosis (PVOD/PCH). Dual-energy CT lung perfusion changes have not been specifically investigated in these two entities.

PURPOSE

To compare dual-energy CT (DECT) perfusion characteristics in PAH and PVOD/PCH, with specific interest in PE-type perfusion defects.

MATERIALS AND METHODS

Sixty-three patients with idiopathic or heritable PAH (group A; n = 51) and PVOD/PCH (group B; n = 12) were investigated with DECT angiography with reconstruction of morphologic and perfusion images.

RESULTS

The number of patients with abnormal perfusion did not differ between group A (35/51; 68.6%) and group B (6/12; 50%) (p = 0.31) nor did the mean number of segments with abnormal perfusion per patient (group A: 17.9 ± 4.9; group B: 18.3 ± 4.1; p = 0.91). The most frequent finding was the presence of patchy defects in group A (15/35; 42.9%) and a variable association of perfusion abnormalities in group B (4/6; 66.7%). The median percentage of segments with PE-type defects per patient was significantly higher in group B than in group A (p = 0.041). Two types of PE-type defects were depicted in 8 patients (group A: 5/51; 9.8%; group B: 3/12; 25%), superimposed on PH-related lung abnormalities (7/8) or normal lung (1/8). The iodine concentration was significantly lower in patients with abnormal perfusion (p < 0.001) but did not differ between groups.

CONCLUSION

Perfusion abnormalities did not differ between the two groups at the exception of a higher median percentage of segments with PE-type defects in patients with PVOD/PCH.

KEY POINTS

• Patchy perfusion defect was the most frequent pattern in PAH. • A variable association of perfusion abnormalities was seen in PVOD/PCH. • Lobular and PE-type perfusion defects larger than a sub-segment were depicted in both PAH and PVOD/PCH patients.

Pulmonary veno-occlusive disease in childhood-a rare disease not to be missed

Pulmonary veno-occlusive disease (PVOD) is a rare disease leading to pulmonary hypertension and potentially death related to right heart failure and/or respiratory insufficiency. Clinical symptoms are heterogenous and nonspecific: fatigue, decreased exercise tolerance, shortness of breath on exertion, cough, dizziness, chest pain with exercise, palpitations, syncope, as well as nonspecific symptoms such as headache, poor appetite, pallor or perioral cyanosis. Mutations in the EIF2AK4 (eukaryotic translation initiation factor 2-alpha kinase 4) have been recently described, other risk factors include exposure to organic solvent and trichloroethylene, tobacco exposure and chemotherapy. Echocardiography helps to estimate right ventricular systemic pressure, but further diagnostic workup includes cardiac catheterization to confirm pulmonary hypertension and increased pulmonary vascular resistance. High-resolution computed tomography reveals typical findings: centrilobular ground-glass nodules or opacities, septal lines, thickened interlobular septa, mosaic perfusion, and lymphadenopathy. Histology remains the gold standard, but carries risks for the patient. Proper workup is essential in order to avoid incorrect diagnosis. Pulmonary hypertension targeted treatment has been used in patients with PVOD, however, experience is limited, vasodilatory effects on pulmonary vasculature may lead to deterioration of the patients and should be used with great caution. Lung transplantation is currently the only valid treatment option for patients with PVOD. With prolonged waiting time and progression of the disease mechanical support could be considered.

Evaluation and management of patients with chronic thromboembolic pulmonary hypertension - consensus statement from the ISHLT

ISHLT members have recognized the importance of a consensus statement on the evaluation and management of patients with chronic thromboembolic pulmonary hypertension. The creation of this document required multiple steps, including the engagement of the ISHLT councils, approval by the Standards and Guidelines Committee, identification and selection of experts in the field, and the development of 6 working groups. Each working group provided a separate section based on an extensive literature search. These sections were then coalesced into a single document that was circulated to all members of the working groups. Key points were summarized at the end of each section. Due to the limited number of comparative trials in this field, the document was written as a literature review with expert opinion rather than based on level of evidence.

Optimizing the diagnosis and assessment of chronic thromboembolic pulmonary hypertension with advancing imaging modalities

Imaging is key to nearly all aspects of chronic thromboembolic pulmonary hypertension including management for screening, assessing eligibility for pulmonary endarterectomy, and post-operative follow-up. While ventilation/perfusion scintigraphy, the gold standard technique for chronic thromboembolic pulmonary hypertension screening, can have excellent sensitivity, it can be confounded by other etiologies of pulmonary malperfusion, and does not provide structural information to guide operability assessment. Conventional computed tomography pulmonary angiography has high specificity, though findings of chronic thromboembolic pulmonary hypertension can be visually subtle and unrecognized. In addition, computed tomography pulmonary angiography can provide morphologic information to aid in pre-operative workup and assessment of other structural abnormalities. Advances in computed tomography imaging techniques, including dual-energy computed tomography and spectral-detector computed tomography, allow for improved sensitivity and specificity in detecting chronic thromboembolic pulmonary hypertension, comparable to that of ventilation/perfusion scans. Furthermore, these advanced computed tomography techniques, compared with conventional computed tomography, provide additional physiologic data from perfused blood volume maps and improved resolution to better visualize distal chronic thromboembolic pulmonary hypertension, an important consideration for balloon pulmonary angioplasty for inoperable patients. Electrocardiogram-synchronized techniques in electrocardiogram-gated computed tomography can also show further information regarding right ventricular function and structure. While the standard of care in the workup of chronic thromboembolic pulmonary hypertension includes a ventilation/perfusion scan, computed tomography pulmonary angiography, direct catheter angiography, echocardiogram, and coronary angiogram, in the future an electrocardiogram-gated dual-energy computed tomography angiography scan may enable a "one-stop" imaging study to guide diagnosis, operability assessment, and treatment decisions with less radiation exposure and cost than traditional chronic thromboembolic pulmonary hypertension imaging modalities.

Chronic Thromboembolic Pulmonary Hypertension: JACC Focus Seminar

Chronic thromboembolic pulmonary hypertension (CTEPH) is the result of pulmonary arterial obstruction by organized thrombotic material stemming from incompletely resolved acute pulmonary embolism. The exact incidence of CTEPH is unknown but appears to approximate 2.3% among survivors of acute pulmonary embolism. Although ventilation/perfusion scintigraphy has been supplanted by computed tomographic pulmonary angiography in the diagnostic approach to acute pulmonary embolism, it has a major role in the evaluation of patients with suspected CTEPH, the presence of mismatched segmental defects being consistent with the diagnosis. Diagnostic confirmation of CTEPH is provided by digital subtraction pulmonary angiography, preferably performed at a center familiar with the procedure and its interpretation. Operability assessment is then undertaken to determine if the patient is a candidate for potentially curative pulmonary endarterectomy surgery. When pulmonary endarterectomy is not an option, pulmonary arterial hypertension-targeted pharmacotherapy and balloon pulmonary angioplasty represent potential therapeutic alternatives.

Pulmonary Veno-Occlusive Disease: A Rare Cause of Pulmonary Hypertension

Pulmonary veno-occlusive disease (PVOD) is a rare entity that is usually mistaken with pulmonary arterial hypertension (PAH) but is considered class I′ of PAH. It is important to subclassify PVOD and distinguish it from PAH as treatment with vasodilators in PVOD patients is controversial and may be fatal. In this article, we describe a case of PVOD and how we diagnosed it.

Clinical Updates on the Diagnosis and Management of Chronic Thromboembolic Pulmonary Hypertension

Introduction: Chronic thromboembolic pulmonary hypertension (CTEPH) is a known sequela after acute pulmonary embolism (PE). It is a debilitating disease, and potentially fatal if left untreated. This review provides a clinically relevant overview of the disease and discusses the usefulness and limitations of the various investigational and treatment options. Methods: A PubMed search on articles relevant to pulmonary embolism, pulmonary hypertension, chronic thromboembolic pulmonary hypertension, pulmonary endarterectomy, and balloon pulmonary angioplasty were performed. A total of 68 articles were found to be relevant and were reviewed. Results: CTEPH occurs as a result of non-resolution of thrombotic material, with subsequent fibrosis and scarring of the pulmonary arteries. Risk factors have been identified, but the underlying mechanisms have yet to be fully elucidated. The cardinal symptom of CTEPH is dyspnoea on exertion, but the diagnosis is often challenging due to lack of awareness. The ventilation/perfusion scan is recommended for screening for CTEPH, with other modalities (eg. dual energy computed tomography pulmonary angiography) also being utilised in expert centres. Conventional pulmonary angiography with right heart catherisation is important in the final diagnosis of CTEPH. Conclusion: Operability assessment by a multidisciplinary team is crucial for the management of CTEPH, as pulmonary endarterectomy (PEA) remains the guideline recommended treatment and has the best chance of cure. For inoperable patients or those with residual disease post-PEA, medical therapy or balloon pulmonary angioplasty are potential treatment options. Keywords: Balloon pulmonary angioplasty, Chronic thromboembolic pulmonary hypertension, Pulmonary embolism, Pulmonary endarterectomy, Pulmonary hypertension

Perfusion Scintigraphy in Diagnosis and Management of Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a life-threatening complication of acute pulmonary embolism (PE). Because the treatment of CTEPH is markedly different from that of other types of pulmonary hypertension, lung ventilation-perfusion (V/Q) scintigraphy is recommended for the workup of patients with unexplained pulmonary hypertension. Lung V/Q scintigraphy is superior to CT pulmonary angiography for detecting CTEPH. Perfusion defect findings of CTEPH can be different from those of acute PE. Familiarity with the patterns of perfusion defects seen during the initial workup of CTEPH and the expected posttreatment changes seen at follow-up imaging is essential for accurate interpretation of V/Q scintigraphy findings. ^©RSNA, 2019.

Mimickers of chronic thromboembolic pulmonary hypertension on imaging tests: a review

Chronic thromboembolic pulmonary hypertension (CTEPH) is caused by mechanical obstruction of large pulmonary arteries secondary to one or more episodes of pulmonary embolism. Ventilation perfusion scan is the recommended initial screening test for this condition and typically shows multiple large mismatched perfusion defects. However, not all patients with an abnormal ventilation perfusion scan have CTEPH since there are other conditions that be associated with a positive ventilation perfusion scan. These conditions include in situ thrombosis, pulmonary artery sarcoma, fibrosing mediastinitis, pulmonary vasculitis and sarcoidosis, among others. Although these conditions cannot be distinguished from CTEPH using a ventilation perfusion scan, they have certain characteristic radiological features that can be demonstrated on other imaging techniques such as computed tomography scan and can help in differentiation of these conditions. In this review, we have summarized some key clinical and radiological features that can help differentiate CTEPH from the CTEPH mimics.

Diagnostic Evaluation of Chronic Thromboembolic Pulmonary Hypertension

Pulmonary hypertension is defined by a mean pulmonary artery pressure greater than 25 mm Hg. Chronic thromboembolic pulmonary hypertension (CTEPH) is defined as pulmonary hypertension in the presence of an organized thrombus within the pulmonary vascular bed that persists at least 3 months after the onset of anticoagulant therapy. Because CTEPH is potentially curable by surgical endarterectomy, correct identification of patients with this form of pulmonary hypertension and an accurate assessment of surgical candidacy are essential to provide optimal care. Patients most commonly present with symptoms of exertional dyspnea and otherwise unexplained decline in exercise capacity. Atypical chest pain, a nonproductive cough, and episodic hemoptysis are observed less frequently. With more advanced disease, patients often develop symptoms suggestive of right ventricular compromise. Physical examination findings are minimal early in the course of this disease, but as pulmonary hypertension progresses, may include nonspecific finding of right ventricular failure, such as a tricuspid regurgitation murmur, pedal edema, and jugular venous distention. Chest radiographs may suggest pulmonary hypertension, but are neither sensitive nor specific for the diagnosis. Radioisotopic ventilation-perfusion scanning is sensitive for detecting CTEPH, making it a valuable screening study. Conventional catheter-based pulmonary angiography retains an important role in establishing the presence and extent of chronic thromboembolic disease. However, computed tomographic and magnetic resonance imaging are playing a growing diagnostic role. Innovative technologies such as dual-energy computed tomography, dynamic contrast-enhanced magnetic resonance imaging, and optical coherence tomography show promise for contributing diagnostic information and assisting in the preoperative characterization of patients with CTEPH.

Imaging in Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is one of the potentially curable causes of pulmonary hypertension and is definitively treated with pulmonary thromboendartectomy. CTEPH can be overlooked, as its symptoms are nonspecific and can be mimicked by a wide range of diseases that can cause pulmonary hypertension. Early diagnosis of CTEPH and prompt evaluation for surgical candidacy are paramount factors in determining future outcomes. Imaging plays a central role in the diagnosis of CTEPH and patient selection for pulmonary thromboendartectomy and balloon pulmonary angioplasty. Currently, various imaging tools are used in concert, with techniques such as computed tomography (CT) and conventional pulmonary angiography providing detailed structural information, tests such as ventilation-perfusion (V/Q) scanning providing functional data, and magnetic resonance imaging providing a combination of morphologic and functional information. Emerging techniques such as dual-energy CT and single photon emission computed tomography-CT V/Q scanning promise to provide both anatomic and functional information in a single test and may change the way we image these patients in the near future. In this review, we discuss the roles of various imaging techniques and discuss their merits, limitations, and relative strengths in depicting the structural and functional changes of CTEPH. We also explore newer imaging techniques and the potential value they may offer.

Chronic Thromboembolic Pulmonary Hypertension: Pearls and Pitfalls of Diagnosis

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by chronic obstruction of major pulmonary arteries by organized thromboembolic material. Untreated CTEPH can result in pulmonary hypertension and eventually right heart failure, yet it is the only form of pulmonary hypertension that is potentially curable with surgical or catheter-based intervention. While early diagnosis is key to increasing the likelihood of successful treatment, CTEPH remains largely underdiagnosed. This article reviews the role of echocardiogram, ventilation/perfusion scan, and other available modalities in the diagnosis of CTEPH.

An Update on the Management of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but life-threatening form of pulmonary artery hypertension that is defined as a mean arterial pulmonary pressure greater than 25mmHg that persists for more than 6 months following anticoagulation therapy in the setting of pulmonary emboli. CTEPH is categorized by the World Health Organization as group IV pulmonary hypertension and is thought to be due to unresolved thromboemboli in the pulmonary artery circulation. Among the 5 classes of pulmonary hypertension, CTEPH is unique in that it is potentially curable with the use of pulmonary thromboendarterectomy surgery. Despite an increasing array of medical and surgical treatment options for patients with CTEPH over the past 2 decades, patients commonly present with advanced disease and carry a poor prognosis, thus, the need for early diagnosis and appropriate referral to an expert center. This review article first highlights the epidemiology, pathophysiology, and clinical presentation of CTEPH. The article then provides diagnostic and therapeutic algorithms for the management of the patient with suspected CTEPH.

Chronic thromboembolic pulmonary hypertension

BACKGROUND

Chronic thromboembolic pulmonary hypertension (CTEPH) results from inadequate recanalization of the pulmonary circulation after pulmonary thromboembolism. Its 2-year prevalence is 1-4% . If untreated, patients with CTEPH have a mean life expectancy of less than three years. Fortunately, a number of effective treatments are now available.

METHODS

This review is based on a selective search of PubMed for pertinent articles published from 1980 to 2014.

RESULTS

The gold-standard test for the exclusion of CTEPH is perfusion scintigraphy: the predictive value of a negative test is nearly 100% . On the other hand, confirmation of a positive diagnosis for treatment planning requires right-heart catheterization and pulmonary angiography. The treatment of first choice for CTEPH is surgical pulmonary endarterectomy (PEA), with which about 70% of patients can be cured. The perioperative mortality of this procedure in experienced centers is now 2-4% . Thirty to 50% of all patients with CTEPH are considered inoperable; for these patients, and for patients with persistent pulmonary hypertension after PEA, the drug riociguat was introduced in Germany in 2014 (the first drug specifically introduced for the treatment of CTEPH). There is also a new interventional treatment option for inoperable patients-pulmonary balloon angioplasty, which is currently being performed in a small number of centers.

CONCLUSION

The timely diagnosis of CTEPH, followed by referral to a specialized center, is now more important than ever, because treatment options are now available for nearly all of the forms in which this disease can manifest itself.

Pulmonary capillary hemangiomatosis: the role of invasive cardiopulmonary exercise testing

Pulmonary capillary hemangiomatosis (PCH) is a rare form of pulmonary arterial hypertension (PAH) characterized by pulmonary capillary proliferation and pseudoinvasion of collagenous septal structures. PCH is often accompanied by veno-occlusive changes and pulmonary hypertensive arterial remodeling. The clinical and pathological diagnosis of PCH can be subtle and easily missed. Most reported cases of PCH have been associated with resting PAH. We report the cases of 3 patients who initially presented with exertional dyspnea with normal to mildly elevated resting pulmonary arterial pressures and marked intrapulmonary shunting. In all 3 patients, invasive cardiopulmonary exercise testing was suggestive of pulmonary vascular disease. Owing to abnormalities on invasive exercise testing, lung biopsies were performed; these were diagnostic of PCH, and the patients were referred for lung transplantation. We describe unique features of these 3 cases-including novel pathological findings and the presence of intrapulmonary shunting in all 3 patients-and we discuss the role of cardiopulmonary exercise testing in the evaluation of PCH.

Diagnostic accuracy of computed tomography for chronic thromboembolic pulmonary hypertension: a systematic review and meta-analysis

This study aimed to determine the diagnostic accuracy of computed tomography imaging for the diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH). Additionally, the effect of test and study characteristics was explored. Studies published between 1990 and 2015 identified by PubMed, OVID search and citation tracking were examined. Of the 613 citations, 11 articles (n=712) met the inclusion criteria. The patient-based analysis demonstrated a pooled sensitivity of 76% (95% confidence interval [CI]: 69% to 82%), and a pooled specificity of 96% (95%CI: 93% to 98%). This resulted in a pooled diagnostic odds ratio (DOR) of 191 (95%CI: 75 to 486). The vessel-based analyses were divided into 3 levels: total arteries、main+ lobar arteries and segmental arteries. The pooled sensitivity were 88% (95%CI: 87% to 90%)、95% (95%CI: 92% to 97%) and 88% (95%CI: 87% to 90%), respectively, with a pooled specificity of 90% (95%CI: 88% to 91%)、96% (95%CI: 94% to 97%) and 89% (95% CI: 87% to 91%). This resulted in a pooled diagnostic odds ratio of 76 (95%CI: 23 to 254),751 (95%CI: 57 to 9905) and 189 (95%CI: 21 to 1072), respectively. In conclusion, CT is a favorable method to rule in CTEPH and to rule out pulmonary endarterectomy (PEA) patients for proximal branches. Furthermore, dual-energy and 320-slices CT can increase the sensitivity for subsegmental arterials, which are promising imaging techniques for balloon pulmonary angioplasty (BPA) approach. In the near future, CT could position itself as the key for screening consideration and for surgical and interventional operability.

Pulmonary thromboendarterectomy in 106 patients with chronic thromboembolic pulmonary hypertension

INTRODUCTION

Pulmonary thromboendarterectomy is the treatment of choice in chronic thromboembolic pulmonary hypertension. We report our experience with this technique.

METHODS

Between February 1996 and June 2014, we performed 106 pulmonary thromboendarterectomies. Patient population, morbidity and mortality and the long-term results of this technique (survival, functional improvement and resolution of pulmonary hypertension) are described.

RESULTS

Subjects' mean age was 53±14 years. A total of 89% were WHO functional class III-IV, presurgery mean pulmonary pressure was 49±13mmHg and mean pulmonary vascular resistance was 831±364 dynes.s.cm(-5). In-hospital mortality was 6.6%. The most important post-operative morbidity was reperfusion pulmonary injury, in 20% of patients; this was an independent risk factor (p=0.015) for hospital mortality. With a 31-month median follow-up (interquartile range: 50), 3- and 5-year survival was 90 and 84%. At 1 year, 91% were WHO functional class I-II; mean pulmonary pressure (27±11mmHg) and pulmonary vascular resistance (275±218 dynes.s.cm(-5)) were significantly lower (p<0.05) than before the intervention. Although residual pulmonary hypertension was detected in 14 patients, their survival at 3 and 5 years was 91 and 73%, respectively.

CONCLUSIONS

Pulmonary thromboendarterectomy offers excellent results in chronic thromboembolic pulmonary hypertension. Long-term survival is good, functional capacity improves, and pulmonary hypertension is resolved in most patients.

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.

Chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare but debilitating and life-threatening complication of acute pulmonary embolism. CTEPH results from persistent obstruction of pulmonary arteries and progressive vascular remodelling. Not all patients presenting with CTEPH have a history of clinically overt pulmonary embolism. The diagnostic work-up to detect or rule out CTEPH should include ventilation-perfusion scintigraphy, which has high sensitivity and a negative predictive value of nearly 100%. CT angiography usually reveals typical features of CTEPH, including mosaic perfusion, part or complete occlusion of pulmonary arteries, and intraluminal bands and webs. Patients with suspected CTEPH should be referred to a specialist centre for right-heart catheterisation and pulmonary angiography. Surgical pulmonary endarterectomy remains the treatment of choice for CTEPH and is associated with excellent long-term results and a high probability of cure. For patients with inoperable CTEPH, various medical and interventional therapies are being developed.

Evaluation of patients with chronic thromboembolic pulmonary hypertension for pulmonary endarterectomy

Pulmonary hypertension as a result of chronic thromboembolic disease (CTEPH) is potentially curable with pulmonary endarterectomy surgery. Consequently, correctly diagnosing patients with this type of pulmonary hypertension and evaluating these patients with the goal of establishing their candidacy for surgical intervention is of utmost importance. And as advancements in surgical techniques have allowed successful resection of segmental-level chronic thromboembolic disease, the number of CTEPH patients that are deemed suitable surgical candidates has expanded, making it even more important that the evaluation be conducted with greater precision. This article will review a diagnostic approach to patients with suspected chronic thromboembolic disease with an emphasis on the criteria considered in selecting patients for pulmonary endarterectomy surgery.

Pulmonary veno-occlusive disease: a misnomer?

Pulmonary veno-occlusive disease (PVOD) is a rare entity with non-specific signs and symptoms and is nearly always associated with a dismal prognosis. This review will first consider pulmonary hypertension in general and then will focus on PVOD specifically with particular attention to the pathophysiology of the disease. Classically PVOD is described as a disease primarily involving obstructed venules, with the arterial side of the circulation involved to a lesser degree. This article discusses the demographics of affected individuals; the ways in which an accurate diagnosis can be made, including imaging features; predisposing diseases and associated disorders; and potential treatment.

Assessment of pulmonary hypertension what CT and MRI can provide

RATIONALES AND OBJECTIVES

Pulmonary hypertension (PH) is a life-threatening condition, characterized by elevated pulmonary arterial pressure, which is confirmed based on invasive right heart catheterization (RHC). Noninvasive examinations may support diagnosis of PH before proceeding to RHC and play an important role in management and treatment of the disease. Although echocardiography is considered a standard tool in diagnosis, recent advances have made computed tomography (CT) and magnetic resonance (MR) imaging promising tools, which may provide morphologic and functional information. In this article, we review image-based assessment of PH with a focus on CT and MR imaging.

CONCLUSIONS

CT may provide useful morphologic information for depicting PH and seeking for underlying diseases. With the accumulated technological advancement, CT and MRI may provide practical tools for not only morphologic but also functional assessment of patients with PH.

Diffusion and perfusion MRI of the lung and mediastinum

With ongoing technical improvements such as multichannel MRI, systems with powerful gradients as well as the development of innovative pulse sequence techniques implementing parallel imaging, MRI has now entered the stage of a radiation-free alternative to computed tomography (CT) for chest imaging in clinical practice. Whereas in the past MRI of the lung was focused on morphological aspects, current MRI techniques also enable functional imaging of the lung allowing for a comprehensive assessment of lung disease in a single MRI exam. Perfusion imaging can be used for the visualization of regional pulmonary perfusion in patients with different lung diseases such as lung cancer, chronic obstructive lung disease, pulmonary embolism or for the prediction of postoperative lung function in lung cancer patients. Over the past years diffusion-weighted MR imaging (DW-MRI) of the thorax has become feasible with a significant reduction of the acquisition time, thus minimizing artifacts from respiratory and cardiac motion. In chest imaging, DW-MRI has been mainly suggested for the characterization of lung cancer, lymph nodes and pulmonary metastases. In this review article recent MR perfusion and diffusion techniques of the lung and mediastinum as well as their clinical applications are reviewed.

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.

From the Archives of the AFIP: pulmonary veno-occlusive disease and pulmonary capillary hemangiomatosis

Pulmonary veno-occlusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH) are two unusual idiopathic disorders that almost uniformly manifest to the clinician as pulmonary arterial hypertension (PAH). Impressive clinical signs and symptoms often obscure the true underlying capillary or postcapillary disorder, thus severely compromising timely and appropriately directed therapy. The hemodynamics of PVOD and PCH are the consequence of a widespread vascular obstructive process that originates in either the alveolar capillary bed (in cases of PCH) or the pulmonary venules and small veins (in PVOD). Since the earliest descriptions of PVOD and PCH, there has been a debate as to whether these are two distinct diseases or varied expressions of a single disorder. The cause of PVOD or PCH has not yet been identified, although there are several reported associations. Without curative lung or heart-lung transplantation, patients with these conditions face inexorable clinical deterioration and death within months to a few short years of initial presentation. Surgical lung biopsy is the definitive diagnostic test, but it is a risky undertaking in such critically ill patients. The imaging manifestations of PVOD and PCH often reflect the underlying hemodynamic derangements, and these findings may assist the clinician in discerning PAH from an underlying capillary or postcapillary process with findings of septal lines, characteristic ground-glass opacities, and occasionally pleural effusion.

Chronic thromboembolic pulmonary hypertension

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

Evaluation of patients for pulmonary endarterectomy

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

High-Resolution Computed Tomographic Imaging and Pathologic Features of Pulmonary Veno-Occlusive Disease: A Review of Three Patients

Pulmonary veno-occlusive disease (PVOD) is a rare and severe form of pulmonary hypertension that is often difficult to differentiate from primary pulmonary hypertension. Differentiating these two entities before medical treatment is critical, as therapy commonly indicated for patients with primary pulmonary hypertension can be harmful and even fatal in patients with PVOD. In the setting of known pulmonary hypertension, computed tomography findings that are highly suggestive of PVOD include extensive, patchy centrilobular ground-glass opacities, ill-defined nodular densities, and interlobular septal thickening. Definitive diagnosis requires lung biopsy, demonstrating fibrous obliteration of the pulmonary venules and small veins of the lobular septa, with secondary medial hypertrophy of the pulmonary arteries. The purpose of this article is to review reported radiographic clues to the diagnosis of PVOD, as well as to illustrate these high-resolution computed tomography findings along with pathologic correlation.

Classificação e avaliação diagnóstica da hipertensão pulmonar

Nos últimos anos, observou-se um grande avanço no conhecimento da fisiopatologia da hipertensão pulmonar, o que permitiu a identificação tanto de fatores de risco bem definidos, quanto de condições clínicas que levam ao seu desenvolvimento. Isso possibilitou ainda uma melhor classificação dos quadros de hipertensão pulmonar, baseada na investigação sistematizada desses quadros, permitindo, em última análise, o correto manuseio terapêutico. Atualmente, busca-se cada vez mais identificar as situações em que o diagnóstico precoce se torna possível, a fim de se instituir medidas terapêuticas em uma fase mais inicial da doença, evitando-se assim sua progressão.

Diagnosis and treatment of pulmonary arterial hypertension

The diagnosis of pulmonary hypertension requires a high index of suspicion and careful attention to assessing the severity and classification of disease. Proper evaluation and understanding of determinants of severity in pulmonary arterial hypertension are necessary to guide appropriate therapy. This article discusses the diagnosis and treatment of this complex and multifactorial disease.

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.

Chronic thromboembolic pulmonary hypertension

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

Chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) should be differentiated from other etiologies of pulmonary hypertension since surgical intervention may be potentially curative. The presentation of this illness is nonspecific and may mimic other cardiopulmonary disease states. Without treatment, progressive pulmonary hypertension, right heart failure, and death will ensue. Echocardiography, lung ventilation-perfusion scan, right heart catheterization, and angiography are required for proper diagnosis and preoperative assessment. Definitive treatment requires surgical resection of thromboembolic material. The role of medical therapy remains to be defined.