Pulmonary arteriovenous malformations: screening procedures and pulmonary angiography in patients with hereditary hemorrhagic telangiectasia

A case of hemoptysis unveiling the unlikely culprit - pulmonary arteriovenous malformation

Pulmonary arteriovenous malformation (PAVM) is a rare vascular anomaly characterized by abnormal communication between the pulmonary artery and vein. It is a rare cause of hemoptysis. Computed tomographic angiography (CTA) has become the preferred and dependable diagnostic approach for identifying PAVM. PAVM embolization is the primary recommended treatment for this condition. We present a case of a 43-year-old male with a complex PAVM in the left lower lobe presenting with hemoptysis treated with an endovascular approach. Following the procedure, the patient's symptoms resolved.

Pulmonary Arteriovenous Malformations: What the Interventional Radiologist Should Know

Pulmonary arteriovenous malformations (PAVMs) are abnormal connections between the pulmonary artery and pulmonary vein bypassing the normal capillary bed causing a right-to-left shunt. The majority (80-90%) of PAVMs are associated with hereditary hemorrhagic telangiectasia (HHT). PAVMs may be asymptomatic or present with symptoms of hypoxia, shortness of breath, migraines, sequelae of paradoxical embolization, or rupture. Transcatheter embolization has become the standard of care. This article will review the clinical presentation, workup, genetics, imaging findings, embolization, complications, and follow-up for patients with PAVMs.

A Comparative Study of Invasive Modalities for Evaluation of Pulmonary Arteriovenous Fistula after Bidirectional Glenn Shunt

Development of pulmonary AV fistula (PAVF) after bidirectional glenn shunt (BDG) results in significant cyanosis, impaired exercise performance, and increased morbidity and mortality. We attempted to detect and quantify PAVF in post-BDG patients by saline contrast transesophageal echocardiography (TEE) and compare with pulmonary angiography and pulmonary vein oximetry. This was a prospective study done between 2017 and 2018. Twenty-five children who underwent BDG and planned for cardiac catheterization prior to Fontan completion were included in the study. All patients underwent pulmonary angiography, oximetry, and saline contrast TEE at the time of cardiac catheterization. Twenty-two patients had undergone unilateral BDG surgery and three were palliated by bilateral BDG. The mean oxygen saturation was 80 ± 5.2%. Thirteen patients (52%) had preserved antegrade pulmonary blood flow. Eighteen patients (72%) had PAVF by angiography and oximetry, while 19 (76%) had PAVF identified by contrast echocardiography. There was moderate correlation between the degree of pulmonary venous desaturation and grading of PAVF by contrast echocardiography. PAVF was predominantly located in the lower zones of the lungs. Higher grades of PAVF were not seen in patients with preserved antegrade flow after BDG. Angiographically detected PAVF showed a steady increase with increasing delay to cardiac catheterization from BDG. Significant reduction in systemic saturation was limited to advanced grades of PAVF in patients after BDG. Saline contrast TEE, pulmonary venous oximetry, and pulmonary angiography equally identified PAVF in patients after BDG. Prognostic utility of the same needs to be assessed by long-term follow-up of these subjects.

Successful treatment of massive haemoptysis in a young woman with anastomosis of right internal mammary artery to right superior pulmonary vein fistula

A 21-year-old, otherwise healthy, female patient was admitted with haemoptysis. Chest X-ray and CT found a consolidated right middle pulmonary lobe. Catheter angiography of ascending aorta visualised two hypertrophic and tortuous branches of the right internal mammary artery with a fistula to the right superior pulmonary vein. The inflow was embolised with coils. Catheter angiography of descending aorta found hypertrophic right bronchial arteries and right phrenic artery supplying a web-like network of vessels, which drained to the right superior pulmonary vein with discrete filling of an accessory right middle pulmonary vein. CT angiography with a catheter for contrast administration in the ascending aorta was performed for characterisation. After two additional episodes of haemoptysis, right middle lobe lobectomy was performed. Perioperatively pulmonary artery blood supply to the right middle pulmonary lobe was absent and an atretic accessory middle pulmonary vein was seen. The patient was discharged 7 days afterwards without sequelae.

Placental Site Trophoblastic Tumor in a Pulmonary Vascular Malformation with Spontaneous Pneumothorax

Placental site trophoblastic tumour (PSTT), a rare variety of gestational trophoblastic disease (GTD), is traditionally limited to the uterus, found within the placental implantation site where it can lead to arteriovenous malformations. GTDs are known to metastasize to the lungs, of which, choriocarcinomas are the commonest. However, arteriovenous malformations related to such metastatic lesions are extremely rare. The occurrence of spontaneous pneumothorax in pulmonary arteriovenous malformations, under any circumstances, is rarely reported. Herein, we report a rare case of metastatic PSTT, found within pulmonary arteriovenous malformations, uniquely presenting with spontaneous pneumothorax.

Pulmonary Vascular Complications in Hereditary Hemorrhagic Telangiectasia and the Underlying Pathophysiology

In this review, we discuss the role of transforming growth factor-beta (TGF-β) in the development of pulmonary vascular disease (PVD), both pulmonary arteriovenous malformations (AVM) and pulmonary hypertension (PH), in hereditary hemorrhagic telangiectasia (HHT). HHT or Rendu-Osler-Weber disease is an autosomal dominant genetic disorder with an estimated prevalence of 1 in 5000 persons and characterized by epistaxis, telangiectasia and AVMs in more than 80% of cases, HHT is caused by a mutation in the ENG gene on chromosome 9 encoding for the protein endoglin or activin receptor-like kinase 1 (ACVRL1) gene on chromosome 12 encoding for the protein ALK-1, resulting in HHT type 1 or HHT type 2, respectively. A third disease-causing mutation has been found in the SMAD-4 gene, causing a combination of HHT and juvenile polyposis coli. All three genes play a role in the TGF-β signaling pathway that is essential in angiogenesis where it plays a pivotal role in neoangiogenesis, vessel maturation and stabilization. PH is characterized by elevated mean pulmonary arterial pressure caused by a variety of different underlying pathologies. HHT carries an additional increased risk of PH because of high cardiac output as a result of anemia and shunting through hepatic AVMs, or development of pulmonary arterial hypertension due to interference of the TGF-β pathway. HHT in combination with PH is associated with a worse prognosis due to right-sided cardiac failure. The treatment of PVD in HHT includes medical or interventional therapy.

High output cardiac failure in 3 patients with hereditary hemorrhagic telangiectasia and hepatic vascular malformations, evaluation of treatment

BACKGROUND

This report addresses how patients with hereditary hemorrhagic telangiectasia (HHT) and high output cardiac failure (HOCF) due to hepatic vascular malformations, should be evaluated and could be treated. HHT is a genetic disorder, leading to vascular abnormalities with potentially serious clinical implications. In the liver, arteriovenous malformations occur in more than 70% of patients, but only about 8% present clinical symptoms such as HOCF with pulmonary hypertension and less commonly portal hypertension, biliary ischemia and hepatic encephalopathy.

RESULTS

Three female patients with HHT type 2 and HOCF caused by severe arteriovenous malformations in the liver are presented in this case series. The patients were seen at the HHT-Centre at Odense University Hospital. Treatment with either orthotopic liver transplantation (one patient) or bevacizumab (two patients) was initiated. All patients experienced marked symptom relief and objective improvement. New York Heart Association-class were improved, ascites, peripheral edema and hence diuretic treatment was markedly reduced or discontinued in all three patients. Bevacizumab also resulted in notable effects on epistaxis and anemia.

CONCLUSION

Our findings substantiate the importance of identification of symptomatic arteriovenous malformations in the liver in patients with HHT. Bevacizumab may possibly, as suggested in this case series and supported by previous case studies, postpone the time to orthotopic liver transplantation or even make it unnecessary. Bevacizumab represents a promising new treatment option, which should be investigated further in clinical trials.

Incidentally Identified Pulmonary AVM: An Unusual Cause for Stroke in a Young Patient

Pulmonary arteriovenous malformation is an uncommon though important potential source for embolic right-to-left extracardiac shunt as a cause for both silent and clinically evident stroke. We present this case to highlight this pathology as a cause for stroke, the importance of treating this malformation, even if incidentally identified, and finally the role of echocardiography in screening for extracardiac shunt and indicating those patients that may benefit from further investigations looking for extracardiac shunt.

Pulmonary arteriovenous malformations: a radiological and clinical investigation of 136 patients with long-term follow-up

AIM

To assess the clinical outcome of patients with and without hereditary haemorrhagic telangiectasia (HHT) after embolisation of pulmonary arteriovenous malformations (PAVM) from a single national centre.

MATERIALS AND METHODS

The present register-based observational study including all patients with PAVM treated with embolisation at a reference centre for HHT and PAVM was undertaken over a 20-year period. Demographic data, HHT genotyping, clinical presentation, and outcome were registered. Patients with HHT were compared to the patients without HHT. Clinical examination, contrast-enhanced echocardiography, and computed tomography (CT) were used to assess the clinical outcome at follow-up.

RESULTS

One hundred and thirty-six patients with 339 PAVM underwent embolisation during the study period: 22 did not have HHT; 62% had HHT1, 10% had HHT2, 4% had JP-HHT, 8% had clinical HHT without identified genetic mutations. Solitary PAVM were more common among patients without HHT than with HHT. Mean follow-up after the first embolisation was 58 months. Mean age at first embolisation was 46.5 years, and at last follow-up 51.8 years. The clinical success without shunt at follow-up was 87%. The 30-day mortality related to the embolisation was 0%. Twenty patients died during follow-up (mean age 69 years). Most patients could be treated during one session, but many will need a long follow-up with repeated clinical examinations and embolisation.

CONCLUSION

The majority of patients referred for embolisation of PAVM had HHT. Multiple PAVM is associated with HHT. Patients with PAVM should be screened for HHT and patients with HHT for PAVM. Embolisation is a safe procedure with high clinical success.

Pulmonary arteriovenous malformations: diagnosis

Pulmonary arteriovenous malformations (PAVMs) are rare, abnormal low resistance vascular structures that connect a pulmonary artery to a pulmonary vein, thereby bypassing the normal pulmonary capillary bed and resulting in an intrapulmonary right-to-left shunt. The spectrum of PAVMs extends from microscopic lesions causing profound hypoxemia and ground glass appearance on computed tomography (CT) but with normal catheter angiographic findings to classic pulmonary aneurysmal connections that abnormally connect pulmonary veins and arteries. These malformations most commonly are seen in hereditary hemorrhagic telangiectasia (HHT). They are rarely due to secondary conditions such as post congenital heart disease surgery or hepatopulmonary syndrome (HPS). The main complications of PAVM result from intrapulmonary shunt and include stroke, brain abscess, and hypoxemia. Local pulmonary complications include PAVM rupture leading to life-threatening hemoptysis or hemothorax. The preferred screening test for PAVM is transthoracic contrast echocardiography (TTCE). CT has become the gold standard imaging test to establish the presence of PAVM. Endovascular occlusion of the feeding artery is the treatment of choice. Collateralization and recanalization of PAVM following treatment may occur, and hence long term clinical and imaging follow-up is required to assess PAVM enlargement and PAVM reperfusion.

Gastrointestinal Manifestations of Hereditary Hemorrhagic Telangiectasia (HHT): A Systematic Review of the Literature

Hereditary hemorrhagic telangiectasia (HHT), also called Osler-Weber-Rendu syndrome, is an autosomal dominant genetic disease that affects the vasculature of numerous organs. The prevalence of HHT is estimated to be between 1.5 and 2 persons per 10,000. While there is still much to learn about this condition, there is an increasing understanding its underlying pathophysiology, genetic basis, presentations, and management. Recognizing that the clinical manifestations of HHT can involve a number of organ systems will provide clinicians with a higher index of suspicion for the disease. This early diagnosis and genotyping can greatly reduce mortality for a patient with HHT through appropriate screening for complications. This review will focus on the gastrointestinal manifestations of HHT and how these can dictate treatment and prognosis.

20-year follow-up study of Danish HHT patients-survival and causes of death

Background

Hereditary Haemorrhagic Telangiectasia (HHT) is a dominantly inheritable disorder, with a wide variety of clinical manifestations due to presence of multiple arteriovenous manifestations. The most common mutations are found in HHT1 (ENG) and HHT2 (ACVRL1) patients, causing alterations in the TGF-β pathway which is responsible for angiogenesis. Modulations of angiogenesis may influence cancer rates. The objective of the study was to evaluate 20-year survival according to HHT subtype, as well as to evaluate differences in causes of death comparing HHT patients and controls. We also wanted to investigate whether cancer morbidity among HHT patients differs from that among controls.

Results

We included all HHT patients in the County of Fyn, Denmark, prevalent as of January 1st 1995 in total 73 HHT patients. In addition three age- and sex- matched controls per HHT patient were evaluated, in total 218 controls (one was lost due to registration failure). The controls were defined at start of follow-up in 1995. Information on lifestyle factors was not available. A total of 32 (44%) HHT patients and 97 (44%) controls passed away during follow-up. The survival curves were evenly distributed showing similar survival rates in the two groups. Cancer diagnoses had been registered in the follow-up period in 4 (5%) HHT patients and in 38 (17%) controls.

Conclusion

The mortality was not increased among Danish HHT patients compared to controls. This study is based on a clinical unselected series of HHT patients with the whole spectrum of severity, independent of need for medical care. Our data also suggest that HHT patients to a lesser degree than the background population are affected by cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s13023-016-0533-9) contains supplementary material, which is available to authorized users.

Characteristic lesion pattern and echocardiographic findings in extra-cardiac shunt-related stroke

Among embolic strokes of undetermined source, under-recognized etiology such as extra-cardiac shunt could be a potential risk factor. We sought to characterize infarction patterns on diffusion-weighted imaging (DWI) and transesophageal echocardiography (TEE) findings in extra-cardiac shunt-related stroke. We enrolled 96 consecutive patients with cryptogenic stroke who had an extra- or intra-cardiac shunt. Diagnosis of the shunt was performed using TEE with agitated saline contrast and pulmonary vein isolation. Infarction patterns on DWI and total lesion volume were analyzed. Bubble amounts through the shunt were classified via the International Consensus Criteria (ICC). Short-term prognosis, patterns and size of DWI lesions, and involved vascular territories were not significantly different between two groups. Multivariate analysis revealed that extra-cardiac shunt group has a smaller total infarct volume (odds ratio [OR]=0.427, 95% confidence interval [95% CI] 0.228-0.799, p=0.008), and significantly higher bubble grade during resting state and lower grade during the Valsalva maneuver (OR= 0.539, 95% CI 0.438-0.663, p<0.001). Stroke related to an extra-cardiac shunt presented smaller infarct volume, favorable clinical outcomes and characteristic finding on TEE with agitated saline contrast. Further study is needed to confirm whether the extra-cardiac shunt is an independent risk factor.

A rare case of pulmonary arterio-venous malformation with recurrent anemia: Hereditary hemorrhagic telangiectasia

Arteriovenous malformation (AVM) is a rare vascular anomaly of the lung, which manifests predominantly as dyspnea (due to right to left shunting) and paradoxical embolism. Hereditary Hemorrhagic Telangiectasia (HHT) being a rare genetic disorder is one of the most common causes of pulmonary arteriovenous malformation (PAVM). Here we report an interesting case of recurrent anemia in an elderly female, who was subsequently found to have multiple cutaneous and mucosal telangiectasias and a large pulmonary AVM.

Carotid ultrasound for pulmonary arteriovenous malformation screening

OBJECTIVE

In patients with hereditary hemorrhagic telangiectasia (HHT), pulmonary arteriovenous malformations (PAVMs) can cause serious neurological complications. Our aim was to evaluate the potential of contrast-enhanced Doppler ultrasound (CE-US) of the common carotid artery as a screening test for detection of PAVMs.

METHODS

A total of 124 consecutive patients with HHT or a positive family history underwent screening for PAVMs with CE-US and thoracic contrast-enhanced magnetic resonance angiography (CE-MRA). CE-US was performed after receiving (D)-galactose microparticulate, and CE-MRA with gadobenate dimeglumine. Twenty-five patients with confirmed PAVMs were referred to conventional pulmonary catheter angiography (PA). Findings on CE-US and CE-MRA were evaluated using contingency tables and McNemar's test.

RESULTS

Using CE-MRA as the reference test, CE-US had a sensitivity of 100%, a specificity of 87%, and a negative predictive value of 100%. In 25 patients who underwent PA, PAVMs that had been diagnosed on CE-US and CE-MRA were confirmed. Of the PAVMs detected by CE-MRA, 24% were not identified on PA.

CONCLUSION

CE-US is a simple, minimally invasive screening method that can easily be performed in different settings. CE-US can predict PAVMs with high probability of success. CE-US may be a simple alternative to transthoracic echocardiography in the assessment of PAVMs in certain HHT-patients.

Surgical management of pulmonary arteriovenous fistula in a female patient

Introduction

We herein describe a rare case of a pulmonary arteriovenous fistula (PAVF).

Presentation of case

The patient was a 20-year-old asymptomatic female, admitted to our hospital because of an abnormal shadow in the right lung field on chest X-rays. Chest computed tomography (CT) revealed two nodules with well-defined margins in the right upper and lower lobes. Contrast-enhanced three-dimensional CT (3D-CT) revealed two enhanced solitary lung nodules which were connected with linear structures suggestive of feeding arteries and drainage veins, respectively. Based on these findings, we made a preoperative diagnosis of PAVF. We performed partial pulmonary resection of the right upper and lower lobes by video-assisted thoracoscopic surgery (VATS). The histopathological findings revealed small and medium-sized vascular channels composed of arteries with mild and irregularly thickened muscle walls and juxtaposed or seemingly anastomosing dilated veins. Based on these findings, a diagnosis of PAVF was confirmed. The patient had an uneventful postoperative course.

Discussion

A PAVF is often associated with various complications, and pregnancy could be a risk factor for these complications because of the increase in the shunt fraction. Females with known PAVF should be maximally treated prior to becoming pregnant as complications of PAVF during pregnancy can have devastating consequences. Therefore, we thought that treatment should be recommended in this case in the event she might later choose to become pregnant.

Conclusion

Surgical resection using VATS for a limited number of ipsilateral isolated pulmonary arteriovenous fistulae is recommended due to its safety, low recurrence and low mortality rate.

Rare manifestations in a case of Osler-Weber-Rendu disease

Osler-Weber-Rendu disease (OWRD) is a rare vascular dysplasia that presents most commonly with epistaxis. The most dreaded complication, however, is an intracranial haemorrhage. We present a patient with two rare manifestations of OWRD, subdural haematoma and portal venous hypertension, both seldom reported in the literature. The patient made a full recovery and continues to do well at this time.

Lung granuloma mimicking pulmonary arteriovenous malformation: Report of a case

INTRODUCTION

While hypervascular lesions in the lung are known to mimic pulmonary arteriovenous malformation (PAVM), here we report a rare case of lung granuloma mimicking PAVM, on which video-assisted thoracic surgery (VATS) was performed.

PRESENTATION OF CASE

A 76-year-old woman without any symptom was admitted to our hospital because of abnormal shadow in the left lung field on chest X-ray. A 20 mm × 14 mm nodule with well-defined margins and smooth contours in the left upper segment was detected in her chest computed tomography (CT). Contrast-enhanced three-dimensional CT (3D-CT) revealed an enhanced solitary lung nodule, which was connected with linear structures suggestive of feeding artery and drainage vein. Thus, we made a preoperative diagnosis of PAVM by performing partial pulmonary resection by VATS. Intraoperatively, elastic hard nodule was palpable in the left upper segment and bruit was not convincing. Histopathological findings revealed multiple foci of coagulative necrosis surrounded by epithelioid cell granuloma containing Langhans-type multinucleated giant cells, involving the medium-sized blood vessels in the pulmonary parenchyma. Abnormal vascular structures, such as PAVM were not convincing. Based on these findings, a diagnosis of left lung granuloma was made.

DISCUSSION

Preoperatively, it was difficult to distinguish the left lung granuloma from PAVM, because hypervascular lesion, such as inflammatory changes can present as strongly enhanced nodules after injection of contrast material.

CONCLUSION

Surgical approach seems appropriate, not only for the purpose of diagnosis, but also for the safety in treatment of a PAVM.

Ischaemic strokes in patients with pulmonary arteriovenous malformations and hereditary hemorrhagic telangiectasia: associations with iron deficiency and platelets

Background

Pulmonary first pass filtration of particles marginally exceeding ∼7 µm (the size of a red blood cell) is used routinely in diagnostics, and allows cellular aggregates forming or entering the circulation in the preceding cardiac cycle to lodge safely in pulmonary capillaries/arterioles. Pulmonary arteriovenous malformations compromise capillary bed filtration, and are commonly associated with ischaemic stroke. Cohorts with CT-scan evident malformations associated with the highest contrast echocardiographic shunt grades are known to be at higher stroke risk. Our goal was to identify within this broad grouping, which patients were at higher risk of stroke.

Methodology

497 consecutive patients with CT-proven pulmonary arteriovenous malformations due to hereditary haemorrhagic telangiectasia were studied. Relationships with radiologically-confirmed clinical ischaemic stroke were examined using logistic regression, receiver operating characteristic analyses, and platelet studies.

Principal Findings

Sixty-one individuals (12.3%) had acute, non-iatrogenic ischaemic clinical strokes at a median age of 52 (IQR 41–63) years. In crude and age-adjusted logistic regression, stroke risk was associated not with venous thromboemboli or conventional neurovascular risk factors, but with low serum iron (adjusted odds ratio 0.96 [95% confidence intervals 0.92, 1.00]), and more weakly with low oxygen saturations reflecting a larger right-to-left shunt (adjusted OR 0.96 [0.92, 1.01]). For the same pulmonary arteriovenous malformations, the stroke risk would approximately double with serum iron 6 µmol/L compared to mid-normal range (7–27 µmol/L). Platelet studies confirmed overlooked data that iron deficiency is associated with exuberant platelet aggregation to serotonin (5HT), correcting following iron treatment. By MANOVA, adjusting for participant and 5HT, iron or ferritin explained 14% of the variance in log-transformed aggregation-rate (p = 0.039/p = 0.021).

Significance

These data suggest that patients with compromised pulmonary capillary filtration due to pulmonary arteriovenous malformations are at increased risk of ischaemic stroke if they are iron deficient, and that mechanisms are likely to include enhanced aggregation of circulating platelets.

Prevalence of left heart contrast in healthy, young, asymptomatic humans at rest breathing room air

Our purpose was to report the prevalence of healthy, young, asymptomatic humans who demonstrate left heart contrast at rest, breathing room air. We evaluated 176 subjects (18-41 years old) using transthoracic saline contrast echocardiography. Left heart contrast appearing ≤3 cardiac cycles, consistent with a patent foramen ovale (PFO), was detected in 67 (38%) subjects. Left heart contrast appearing >3 cardiac cycles, consistent with the transpulmonary passage of contrast, was detected in 49 (28%) subjects. Of these 49 subjects, 31 were re-evaluated after breathing 100% O2 for 10-15min and 6 (19%) continued to demonstrate the transpulmonary passage of contrast. Additionally, 18 of these 49 subjects were re-evaluated in the upright position and 1 (5%) continued to demonstrate the transpulmonary passage of contrast. These data suggest that ~30% of healthy, young, asymptomatic subjects demonstrate the transpulmonary passage of contrast at rest which is reduced by breathing 100% O2 and assuming an upright body position.

Iron deficiency anemia related to hereditary hemorrhagic telangiectasia: response to treatment with bevacizumab

Hereditary hemorrhagic telangiectasia (HHT) is a rare autosomal dominant condition associated with arteriovenous malformations (AVMs) or telangiectasias of the pulmonary, gastrointestinal or hepatic circulations. The authors present a case of a 52-year-old woman with a known diagnosis of HHT who presented for evaluation of anemia. She had an extensive history of iron sucrose infusions, frequent blood transfusions and hospitalizations for anemia related to gastrointestinal bleeding and epistaxis. The patient was treated with bevacizumab at a dose of 5 mg/kg infusion every 2 weeks for 4 cycles. In the next 4 months, her hemoglobin improved to 13.7 g/dL and she did not require iron or packed red blood cell transfusions for the next 8 months. Abnormal angiogenesis primarily due to mutations in the transforming growth factor β receptor endoglin and the activin receptor-like kinases is a central contributor to the formation of AVMs in HHT. Bevacizumab is a monoclonal antibody against vascular endothelial growth factor and therefore may be a useful treatment against AVM formation in patients with HHT. The authors do caution that therapy has to be individualized as there are no randomized trials regarding its usage in patients with HHT.

[Paradoxical brain embolism mediated through a pulmonary arteriovenous malformation with hereditary hemorrhagic telangiectasia in a Japanese patient]

We report a case of paradoxical brain embolism mediated through a pulmonary arteriovenous malformation (PAVM) with hereditary hemorrhagic telangiectasia (HHT). A 25-year-old right handed man was admitted to our hospital after sudden headache and visual field abnormality. In neurologic examinations, he had left superior-quadrantanopsia. Laboratory findings showed iron deficiency anemia. Diffusion weighted images disclosed a high-signal-intensity area in the right occipito-temporal lobe, and intraarterial digital subtraction cerebral angiography revealed occlusion of the right posterior cerebral artery. Transesophageal echocardiography revealed continuous right-to-left shunt. We confirmed his history of spontaneous recurrent epistaxis and the first-degree relatives with epistaxis or PAVM. A contrast enhanced CT scan of the chest revealed a PAVM. The diagnosis of paradoxical brain embolism mediated through the PAVM with HHT was, thus, established. The PAVM was occluded by using embolization coils successfully. In Asian countries, the prevalence of PAVM with HHT is thought to be lower than in European countries. We should carefully take medical and family histories, especially epistaxis, in a young stroke patient.

Rare lung disease research: strategies for improving identification and recruitment of research participants

Research in rare lung diseases faces methodologic limitations by virtue of the small number of participants available to be studied. We explored several strategies that may improve researchers' ability to identify and recruit research participants with rare lung diseases. We provide an overview of strategies based on available evidence, previously used approaches, and reasoning. First, disease detection is generally poor and may be improved through strategies targeted at primary care practitioners or directly at patients, thus increasing the pool of patients available for research studies. Next, standardization of case definitions in rare lung diseases is often lacking, hindering research recruitment efforts because of confusion over appropriate recruitment criteria. Expert consensus statements can enhance both clinical care and research recruitment by standardizing definitions. Finally, recruitment strategies using rare lung disease registries, clinical research networks, novel Internet-based direct patient recruitment approaches, and patient organizations may facilitate recruitment of patients with rare lung diseases. In summary, although several strategies for improving the identification and recruitment of research participants with rare lung diseases have been proposed, published examples are few. Objective measurement and reporting of novel recruitment methods and collaboration among researchers facing the same limitations across various rare lung diseases are required. Advancements in this area are vital to the design and performance of much-needed robust clinical studies across the spectrum of rare lung diseases.

Poul Erik Andersen's radiological work on Osteochondrodysplasias and interventional radiology

Poul Erik Andersen is a Professor and Interventional Radiologist at the University of Southern Denmark, Odense and Odense University Hospital, Denmark. His innovative and expertise is primarily in vascular interventions where he has introduced and developed many procedures at Odense University Hospital. His significant experience and extensive scientific work has led to many posts in the Danish Society of Interventional Radiology, the European Society of Radiology and the Cardiovascular and Interventional Radiological Society of Europe, where he is a fellow and has passed the European Board of Interventional Radiology - The European qualification in Interventional Radiology.

Reproducibility of oxygen saturation monitoring during six-minute walk test and exercise stress test in patients with pulmonary arteriovenous malformations associated with hereditary hemorrhagic telangiectasia

Patients with pulmonary arteriovenous malformations (PAVMs) are at risk for multiple complications and require close follow-up. We investigated the reproducibility of the 6-minute walk test (6MWT) and exercise stress test (EST) for the evaluation of low oxygen saturation in patients with PAVMs. Twenty-two patients with PAVMs, most of whom had hereditary hemorrhagic telangiectasia (HHT), participated in a Human Investigations Committee-approved protocol. Patients ranged from 9 to 74 years of age (mean 28) and had a broad spectrum of anatomic subtypes of PAVMs, including focal and diffuse. Standard 6MWT and cycle ergometry EST were both performed twice with adequate rest between tests. Heart rate (HR) and oxygen saturation were measured at the beginning and end of each test. Distance walked and maximum resistance was also recorded. The intraclass correlation coefficients (r(i)) at the end of 6MWT were as follows: HR (r(i) = 0.940; 95% confidence interval [CI] 0.863-0.975), oxygen saturation (r(i) = 0.973; 95% CI 0.933-0.989), and distance (r(i) = 0.942; 95% CI 0.867-0.975). The r(i)s at the end of EST were as follows: HR (r(i) = 0.941; 95% CI 0.865-0.975), oxygen saturation (r(i) = 0.993; 95% CI 0.982-0.997), and maximum resistance (r(i) = 0.941; 95% CI 0.864-0.975). 6MWT and EST were reproducible measures of exercise capacity and oxygen saturation and are potential adjunct tests in the follow-up assessment for patients with PAVMs.

Pulmonary arteriovenous malformation: An uncommon disease with common presentation

A 45-year-old male presented with massive hemoptysis, clubbing in all limbs, disproportionate hypoxia and persistent ill-defined shadow in left lower zone in chest radiograph since his childhood. The patient received empirical anti-tuberculosis treatment and the chest X-ray finding was misinterpreted as tuberculoma. Subsequently, CT pulmonary angiography proved it to be a case of a simple type solitary pulmonary arteriovenous malformation with a saccular aneurysm in left lower lobe.

Pulmonary pathways and mechanisms regulating transpulmonary shunting into the general circulation: an update

Embolic insults account for a significant number of neurologic sequelae following many routine surgical procedures. Clearly, these post-intervention embolic events are a serious public health issue as they are potentially life altering. However, the pathway these emboli utilize to bypass the pulmonary microcirculatory sieve in patients without an intracardiac shunt such as an atrial septal defect or patent foramen ovale, remains unclear. In the absence of intracardiac routes and large diameter pulmonary arteriovenous malformations, inducible large diameter intrapulmonary arteriovenous anastomoses in otherwise healthy adult humans may prove to be the best explanation. Our group and others have demonstrated that inducible large diameter intrapulmonary arteriovenous anastomoses are closed at rest but can open during hyperdynamic conditions such as exercise in more than 90% of healthy humans. Furthermore, the patency of these intrapulmonary anastomoses can be modulated through the fraction of inspired oxygen and by body positioning. Of particular clinical interest, there appears to be a strong association between arterial hypoxemia and neurologic insults, suggesting a breach in the filtering ability of the pulmonary microvasculature under these conditions. In this review, we present evidence demonstrating the existence of inducible intrapulmonary arteriovenous anastomoses in healthy humans that are modulated by exercise, oxygen tension and body positioning. Additionally, we identify several clinical conditions associated with both arterial hypoxemia and an increased risk for embolic insults. Finally, we suggest some precautionary measures that should be taken during interventions to keep intrapulmonary arteriovenous anastomoses closed in order to prevent or reduce the incidence of paradoxical embolism.

Small- and moderate-size right-to-left shunts identified by saline contrast echocardiography are normal and unrelated to migraine headache

BACKGROUND

We suspected, based on clinical experience, that the prevalence of both intracardiac and pulmonary arteriovenous malformations (PAVMs) is higher than previously reported in a healthy population when using modern ultrasound technology combined with a rigorous saline contrast echocardiogram (SCE) protocol. We hypothesized the prevalence of right-to-left shunts (RLSs) would be so high when using this sensitive technique that there would be no significant association of RLS with migraine headache.

METHODS

We recruited 104 healthy volunteers to undergo an SCE followed by completion of a migraine questionnaire. The SCEs were meticulously graded for shunt size and location based on left-sided heart contrast quantity and timing. The migraine headache questionnaire was graded by a neurologist blinded to SCE results.

RESULTS

One hundred four subjects underwent the study protocol. We found 71% of subjects exhibited evidence of RLS. Patent foramen ovale (PFO) was identified in 40 (38%), PAVM was identified in 29 (28%), and five subjects had evidence of both (5%). Based on questionnaires, 42 (40%) of the subjects had migraine headache (29% with aura). There was no significant association of migraine headache with PFO (OR, 0.59; 95% CI, 0.16-2.12; P = .54) or PAVM (OR, 0.8; 95% CI, 0.34-1.9; P = .67), although only 13 (13%) of the subjects had evidence of large RLS.

CONCLUSIONS

When using modern ultrasound technology combined with a rigorous SCE technique, the majority of healthy subjects demonstrate some degree of RLS. PAVM in an otherwise healthy population is common. Small- and moderate-size RLSs do not appear to be significantly associated with migraine headache.

[Pulmonary arteriovenous malformation in a bronchoscopy simulating a carcinoid tumour]

The authors report a case of pulmonary arteriovenous malformation in a 48-year-old man. The bronchoscopy revealed a fragile lingular tumoral formation. The diagnosis was based on the thoracotomy and the histopathological findings. The endoscopic features and the different diagnostic options of pulmonary arteriovenous malformation are discussed.

Pulmonary arteriovenous fistula within a pulmonary cyst - evaluation with CT pulmonary angiography

Pulmonary arteriovenous malformations (PAVMs) are abnormal direct communications between pulmonary arteries and pulmonary veins. These abnormal communications result in an anatomical right-to-left shunt that reduces the arterial oxygen saturation and may cause hypoxaemia and dyspnoea. Although PAVMs frequently remain undiagnosed, they are associated with severe morbidity in the form of ischaemic strokes and brain abscesses. We report a case of incidental CT angiography depiction of a PAVM within a pulmonary cyst. To the best of our knowledge, no such case has been described previously. On the basis of its appearance and lack of typical clinical features of hereditary haemorrhagic telangiectasia (HHT), we suggest that this PAVM actually represents an acquired fistula from a previously unrecognised focal pulmonary insult, such as trauma or infection, that simultaneously evolved into a pulmonary arteriovenous fistula (PAVF) within a traumatic pulmonary cyst or pneumatocele.

[Isolated pulmonary arteriovenous malformation (PAVM)--report of three cases]

Isolated PAVM is rare condition and only a few cases of VATS (Video-Assisted Thoracoscopic Surgery) resection have been reported so far. Since the clinical course of PAVM is not entirely benign due to its possible progression and serious complications (paradoxical emboli, stroke, brain abscess, etc.), the most radical least invasive treatment should be chosen in all cases nowadays. Embolization may be incomplete and carries a risk of accidental systemic embolization, therefore surgical excision is the preferred method of choice. In cases of surgical resections, pulmonary parenchyma sparing techniques such as wedge resection and local excision by VATS is desirable, if possible. We present three patients who were admitted with asymptomatic pulmonary round shadow (umbra rotunda) for further investigation and treatment. We have performed two wedge resections by VATS and one segmentectomy via axillary thoracotomy. We wish to emphasize the importance of this disease to consider in differential diagnosis to avoid complications.

Embolization of pulmonary arteriovenous malformations with amplatzer vascular plugs: safety and midterm effectiveness

PURPOSE

To evaluate the safety and effectiveness of Amplatzer vascular plugs (AVPs) for percutaneous closure of arteries feeding pulmonary arteriovenous malformations (PAVMs).

MATERIALS AND METHODS

Over a 45-month period, 24 consecutive patients with at least one PAVM treated with an AVP were selected from a database on patients with a PAVM who received embolotherapy. Immediate technical success was defined as the complete absence of flow through the PAVM after embolization without the need for additional embolization material. Success on follow-up imaging was defined as a reduction in size of at least 70% of the aneurysm or draining vein on follow-up computed tomography or the absence of flow through the PAVM on a subsequent pulmonary angiogram.

RESULTS

Thirty-seven AVPs were used to close 36 feeding arteries in 35 PAVMs in seven male and 17 female patients aged 11-86 years (mean age, 50 y). Technical success was achieved in 35 feeding arteries (97%). One feeding artery required two AVPs for closure. There were no immediate procedure-related complications. At a mean clinical follow-up of 322 days (range, 1-1,126 d), all patients were alive without new PAVM-related complications. Imaging follow-up was available for 29 embolized vessels (81%) with a mean follow-up of 418 days (range, 40-937 d), and recanalization occurred in two treated vessels (7%).

CONCLUSIONS

AVPs are safe and effective for closure of PAVMs feeding vessels that can be reached with a guiding catheter, with an acceptable rate of recanalization.

Real prevalence of pulmonary right-to-left shunt according to genotype in patients with hereditary hemorrhagic telangiectasia: a transthoracic contrast echocardiography study

BACKGROUND

Transthoracic contrast echocardiography (TTCE) can detect pulmonary right-to-left shunting (RLS) and is used to screen for pulmonary arteriovenous malformations (PAVMs) in patients with hereditary hemorrhagic telangiectasia (HHT). We studied the prevalence and size of pulmonary RLS in HHT type 1, HHT type 2, and HHT-negative controls, and its positive predictive value (PPV) and negative predictive value (NPV) for PAVMs that can be treated by embolotherapy.

METHODS

In 343 consecutive persons referred for possible HHT as first-degree family members of index patients a TTCE and chest CT scan were performed. All persons were offered genetic analysis.

RESULTS

An HHT-causing mutation was confirmed in 92 (mean age 41 ± 15 y; 59% female) HHT1 relatives and in 97 (mean age 47 ± 14 y; 52% female) HHT2 relatives. TTCE showed a pulmonary RLS in 78 (85%) HHT1- and 34 (35%) HHT2-related mutation carriers, respectively (P < .0001). In HHT1 relatives, 29 of 53 (55%) PAVMs and in HHT2 relatives three of 17 (18%) PAVMS were treated, resulting in a PPV of TTCE for treatable PAVMs of 36.3% and 8.3%, respectively. The accompanying NPV was 100%. A minimal, moderate, or large shunt was present in 12 (13%), 24 (26%), and 42 (46%) HHT1-related, and in 20 (21%), 6 (6%), and 8 (8%) HHT2-related mutation carriers, respectively (P for trend < .0001). A large shunt predicted treatable PAVMs in 55.8% of HHT1 relatives and 37.5% of HHT2 relatives. TTCE was positive in four (6%) of 63 persons without HHT.

CONCLUSIONS

A pulmonary shunt on TTCE is more prevalent and larger in HHT1- compared with HHT2-related mutation carriers. Shunt grading is helpful to predict treatable PAVMs, particularly in the HHT2 group. TTCE is also positive in a small fraction of persons without HHT.

Hereditary haemorrhagic telangiectasia

Hereditary haemorrhagic telangiectasia (also known as Osler-Weber-Rendu syndrome) is a relatively common, under-recognized autosomal-dominant disorder that results from multisystem vascular dysplasia. It is characterized by telangiectases and arteriovenous malformations of skin, mucosa and viscera. This article summarizes the clinical manifestations and the management of this disorder and its management. This review underscores an urgent need to conduct prospective multicentre studies to develop evidence-based management guidelines for this disease.

Surgery for multiple and diffuse pulmonary arteriovenous fistulas during childhood

We report an uncommon clinical case of multiple, diffuse pulmonary arteriovenous fistulas that occurred during childhood. A 15-year-old Japanese girl with multiple pulmonary arteriovenous fistulas presented with moderate hypoxemia and was treated by left lower lobectomy for complete resection of the arteriovenous fistulas. Clinical and radiographic features are presented.

CT findings in unilateral hepatopulmonary syndrome after the Fontan operation

BACKGROUND

Patients with complex congenital heart defects palliated by connecting the systemic veins directly to the pulmonary circulation are known to develop hepatopulmonary syndrome (HPS). Although rare, HPS can develop following the Fontan operation.

OBJECTIVE

To present and analyse the CT findings of HPS in patients with a Fontan circulation.

MATERIALS AND METHODS

From May to December 2005, six patients with HPS following the completion of a Fontan circulation were evaluated. CT findings were reviewed and were compared with angiographic findings.

RESULTS

All six patients showed unilateral involvement. All patients except one had inferior vena cava (IVC) interruption with azygos continuation. CT scans showed abnormal vascular dilatation in one lung, and properly demonstrated the anatomy causing the hepatic venous blood to flow preferentially into one lung. These CT findings correlated well with the angiography findings.

CONCLUSION

HPS that develops after the Fontan procedure is typically unilateral and is often associated with IVC interruption and azygos or hemiazygos continuation. CT demonstrates dilatation of pulmonary vessels in the affected lung and may be able to demonstrate the underlying anatomical cause for the predilection of hepatic venous flow to the contralateral lung.

Grading of pulmonary right-to-left shunt with transthoracic contrast echocardiography: does it predict the indication for embolotherapy?

RATIONALE

Pulmonary arteriovenous malformations (PAVMs) are associated with severe neurologic complications in patients with hereditary hemorrhagic telangiectasia (HHT). Therefore, screening is warranted. Transthoracic contrast echocardiography (TTCE) can effectively detect a pulmonary right-to-left shunt (RLS).

OBJECTIVES

To determine prospectively the predictive value of TTCE grading to detect PAVMs on high-resolution CT (HRCT) scans of the chest and the indication for embolotherapy.

METHODS

Three hundred seventeen patients, referred for possible HHT, were screened for PAVMs. Patients who underwent both chest HRCT scanning and TTCE were included in the study (n = 281). For the purposes of this study we used a 3-point grading scale, and shunt grades 3 and 4 according to the classification model of Barzilai et al were combined. Embolotherapy was performed of all PAVMs judged large enough for treatment.

RESULTS

Echocardiographic criteria for a pulmonary RLS were present in 105 patients (41%) [mean (+/- SD) age, 43.7 +/- 15.7 years; female gender, 63%]. Chest HRCT scan findings were positive in 55 patients (52%) in this group. The positive predictive value of shunt grade for the presence of PAVMs on chest HRCT scans was 22.9% for grade 1 (n = 35), 34.8% for grade 2 (n = 23), and 83.0% for grade 3 (n = 47), respectively. None of the patients with PAVMs seen on chest HRCT scans and a TTCE grade 1 (n = 8) or 2 (n = 8) were candidates for embolotherapy. Of 39 patients with TTCE grade 3 and PAVMs seen on chest HRCT scans, 26 patients (67%) underwent embolotherapy.

CONCLUSION

An increased echocardiographic shunt grade correlates with an increased probability of PAVMs seen on chest HRCT scans. Only patients with a TTCE grade 3 displayed PAVMs on chest HRCT scans that were large enough for embolotherapy.