Pulmonary arteriovenous malformations. A state of the art review

Nonthrombotic Pulmonary Embolism From Inorganic Particulate Matter and Foreign Bodies

Nonthrombotic pulmonary embolism (NTPE) is a complete or partial occlusion of the pulmonary vasculature by various organic and inorganic materials. These materials include organic particulate matter (PM) such as adipocytes, tumor cells, bacteria, fungi, or gas and inorganic PM. Although NTPE due to organic PM has been extensively reported in the medical literature, there are no comprehensive reviews of inorganic material embolizing to the lungs. The purpose of this article is to examine the current literature describing NTPE resulting from inorganic PM and foreign bodies. Cases of NTPE are uncommon and often difficult to diagnose. The diagnosis is challenging due to its varied presentation, clinical features, and unusual radiologic features. In contrast to the "classic" pulmonary thromboembolism, the pathophysiologic effects of embolism by PM are not only mechanical but also a consequence of the nature of the offending material. NTPE caused by these substances can be relatively innocuous, life-threatening, or lead to chronic pulmonary disease, if left undetected. We hope that the heightened sense of awareness of this entity may allow earlier diagnosis and recognition of its complications.

Recurrent Stroke in a Young Woman with a Single Pulmonary Arteriovenous Fistula: An Unusual Association

Introduction

Cryptogenic stroke is present in about 40% of ischemic stroke patients. Extracardiac shunt related to pulmonary arteriovenous fistula (PAVF) could be a rare potential risk factor for embolic stroke. Most PAVFs are multiple, congenital, and associated with hereditary conditions. On the other hand, isolated PAVFs are rare conditions and an uncommon cause of cryptogenic stoke.

Case Report

We describe a case of a young woman without history of respiratory diseases or vascular risk factors, who presented with acute onset of transitory aphasia and right hemiplegia. She had a history of a transient ischemic attack, 3 years before, and migraine headaches. Brain MRI showed an acute cortical ischemic lesion and a chronic ischemic lesion. Diagnostic workup with transcranial Doppler ultrasonography revealed a significant right-to-left shunt with curtain pattern, and echocardiogram did not show structural abnormalities. An isolated small PAVF was diagnosed on pulmonary angiogram. Despite the rare association between isolated small PAVF and stroke, we decided to treat it with coil embolization because of recurrence of stroke, cortical lesions suggestive of embolic source, significant right-left shunt, and risk of future complications.

Conclusions

This case highlights the importance of search, identification, and interpretation of causes of cryptogenic strokes to better choose therapy to reduce the stroke recurrence risk. Although unusual, PAVF detection is a treatable cause of stroke and the therapeutic decisions should take into account the characteristics of the PAVF and the degree of suspicion regarding the cause-effect relationship between PAVF and stroke.

Pulmonary arteriovenous malformation in a neonate: a condition commonly misdiagnosed

Pulmonary arteriovenous malformations (PAVMs) are congenital defects in the form of an anomalous bridging between a pulmonary arterial and venous system that sidesteps the normal pulmonary capillary. This anomaly is usually associated with hereditary hemorrhagic telangiectasia, leftover small group are sporadic cases but may occur as an isolated anomaly or as multiple lesions. Rarely, such abnormalities can be acquired. Few cases are diagnosed in the neonatal period, as it will pass silent without symptoms. Clinical manifestations occur soon after birth as cyanosis, tachypnea, and an abnormal sound as bruit over the AVM; and the most important point is the clinical suspicion of diagnosis in absence of pulmonary parenchymal and cardiac disease that can explain the persistence of cyanosis. We report a successful Amplatzer vascular plug occlusion of isolated multiple left side PAVM in a neonate, which was done on two stages with a 6 months interval, with no complications. Over 2-year follow-up, the patient remained well with no symptoms.

Pulmonary Complications of Obstetric and Gynecologic Conditions

The respiratory and the female reproductive systems are not embryologically or functionally related. However, the reproductive system can exert significant effects on the respiratory system as a result of the various hormonal changes that occur during a woman’s menstrual cycle and especially during pregnancy. In addition, there are several unique gynecologic and/or obstetric conditions that can directly affect the respiratory system. The following chapter reviews the effects of pregnancy on the respiratory system, as well as the special issues concerning the management of common respiratory conditions (e.g., pneumonia, asthma) during pregnancy. In addition it reviews several gynecologic disorders with unique pulmonary complications.

Pulmonary arteriovenous malformations in hereditary haemorrhagic telangiectasia: Correlations between computed tomography findings and cerebral complications

OBJECTIVES

Computed tomography (CT) is the modality of choice to characterise pulmonary arteriovenous malformations (PAVMs) in patients with hereditary haemorrhagic telangiectasia (HHT). Our objective was to determine if CT findings were associated with frequency of brain abscess and ischaemic stroke.

METHODS

This retrospective study included patients with HHT-related PAVMs. CT results, i.e. PAVM presentation (unique, multiple, disseminated or diffuse), the number of PAVMs and the largest feeding artery size, were correlated to prevalence of ischaemic stroke and brain abscess. All CTs were reviewed in consensus by two radiologists.

RESULTS

Of 170 patients, 73 patients had unique (42.9 %), 49 multiple (28.8 %), 36 disseminated (21.2 %) and 12 diffuse (7.1 %) PAVMs. Fifteen patients presented with brain abscess; 26 patients presented with ischaemic stroke. The number of PAVMs was significantly correlated with brain abscess (11.5 vs. 6.2, respectively; p=0.025). The mean diameter of the largest feeding artery was significantly correlated with ischaemic stroke frequency (4.9 vs. 3.2 mm, respectively; p=0.0098).

CONCLUSIONS

The number of PAVMs correlated significantly with risk of brain abscess, and a larger feeding artery significantly with more ischaemic strokes. These findings can lead to a better recognition and management of the PAVMs at risk of cerebral complications.

KEY POINTS

• Chest CT helps clinicians to facilitate appropriate PAVM management strategies. • Pulmonary arteriovenous malformation CT findings are correlated with risk of cerebral complications. • Risk of brain abscess is significantly correlated with number of PAVMs. • Risk of ischaemic stroke is significantly correlated with large feeding artery PAVMs. • Prevalence of observed of brain abscess and ischaemic stroke is 26 %.

Contemporary Management of Pulmonary Arteriovenous Malformations

Pulmonary arteriovenous malformations (PAVMs) are atypical vascular structures involving a direct connection between the pulmonary arterial and venous circulations. While PAVMs are a relatively uncommon disorder, unmanaged cases are at risk for the development of serious complications including embolization and infection. Since their first description in 1897, PAVMs have been identified and treated in a variety of ways. Advancements in diagnostic methods and operative techniques have allowed for more effective treatment of the disease. Most recently, the use of vascular plug transcatheter embolization has been described as an effective therapeutic procedure in the management of PAVMs. In this report, we present our experience with nine cases of PAVMs treated at the University of Kentucky, including special consideration of an exemplary case that illustrates the typical course of treatment for the disease.

Non–contrast-enhanced magnetic resonance angiography using time-spatial labeling inversion pulse technique for differentiation between pulmonary varix and arteriovenous malformation

Pulmonary varix is a rare entity that presents as a focal aneurysmal dilatation of the pulmonary vein and is frequently mistaken for a pulmonary arteriovenous malformation (PAVM). It is important to distinguish between pulmonary varix and PAVM because the former does not usually require treatment. We present the findings of non–contrast-enhanced magnetic resonance angiography with the time-spatial labeling inversion pulse technique in case of pulmonary varix and PAVM and the utility of this method for differentiating between these diseases.

The Lung in Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is a dominantly inherited genetic vascular disorder with an estimated prevalence of 1 in 6,000, characterized by recurrent epistaxis, cutaneous telangiectasia, and arteriovenous malformations (AVMs) that affect many organs including the lungs, gastrointestinal tract, liver, and brain. Its diagnosis is based on the Curaçao criteria, and is considered definite if at least 3 of the 4 following criteria are fulfilled: (1) spontaneous and recurrent epistaxis, (2) telangiectasia, (3) a family history, and (4) pulmonary, liver, cerebral, spinal, or gastrointestinal AVMs. The focus of this review is on delineating how HHT affects the lung.

Hemoptysis: Beyond routine chest computed tomography and bronchoscopy

Hemoptysis is considered as a medical emergency which requires urgent stabilization with identification and correction of underlying etiology. Diagnosis of the cause of hemoptysis is not always readily identified after bronchoscopy and conventional computed tomography (CT) chest. Arteriovenous malformation (AVM) is a rare but important cause of massive hemoptysis which can be easily picked up by the use of double turn contrast CT chest. We here report a rare congenital AVM anomaly called Klippel-Trenaunay-Parks-Weber syndrome as a cause of massive hemoptysis and utility of double turn CT in diagnosing AVM as a cause of hemoptysis.

Does the type and size of Amplatzer vascular plug affect the occlusion time of pulmonary arteriovenous malformations?

PURPOSE

Occlusion time (OT) is an important factor in the treatment of pulmonary arteriovenous malformations (PAVMs) since it can lead to serious complications. The purpose of our study is to calculate the OT of Amplatzer vascular plug (AVP, St Jude Medical), and correlate it to the type of the device used (AVP or AVP 2) and the percent of device oversizing. Technical success rates and complications were also recorded.

METHODS

We retrospectively studied a total of 19 patients with 47 PAVMs who received percutaneous transcatheter embolization therapy using either AVP or AVP 2. We recorded the location, type, feeding artery diameter, AVP device used, and OT of each PAVM. We correlated the percent of device oversizing and the type of AVP with the OT. We also studied the rate of persistence of PAVM for both devices.

RESULTS

Forty-six (98%) of the PAVMs were simple. Device diameters ranged from 4.0-16.0 mm with device oversizing ranging between 14% and 120%. There was a statistically significant difference in the OT of AVP and AVP 2 (3 min 54 s vs. 5 min 30 s, P = 0.030). There was a weak positive correlation between OT and device oversizing for AVP (r=0.246, P = 0.324) and AVP 2 (r=0.261, P = 0.240). No major complications were identified. Immediate technical success rate was 100%.

CONCLUSION

The use of AVP 2, and increase in device oversizing were not associated with reduction in the OT of PAVMs. There was no reported difference in safety between the two devices, and no major complications were noted.

Surgery versus percutaneous transcatheter embolization for pulmonary arteriovenous malformation: Analysis of a national inpatient database in Japan

OBJECTIVE

Although the treatment options for pulmonary arteriovenous malformation are surgery and percutaneous transcatheter embolization, no study has compared the outcomes between these 2 treatments.

METHODS

From the Japanese Diagnosis Procedure Combination database, the medical records of 996 patients who received treatment for pulmonary arteriovenous malformation between 2010 and 2015 were retrospectively reviewed. We created balanced groups for surgery or percutaneous transcatheter embolization using propensity scoring. The primary outcome was the rate of reintervention for pulmonary arteriovenous malformation, and the secondary outcomes were composite complications and postoperative length of stay. Patients who had any 1 of the complications during hospitalization were considered to have experienced a composite complication.

RESULTS

Of the total sample, 211 patients underwent surgery and 785 patients underwent percutaneous transcatheter embolization. By using 1-to-1 propensity score matching, 202 pairs were selected. Compared with percutaneous transcatheter embolization, surgery was associated with a significantly higher proportion of composite complications (6.9% vs 2.0%, P = .027) and longer postoperative length of hospital stay (median, 6 vs 2 days, P < .01). However, surgery resulted in a significantly lower rate of reintervention for pulmonary arteriovenous malformation (2.1% vs 8.3% at 2 years; P < .01).

CONCLUSIONS

Percutaneous transcatheter embolization had the advantage in composite complications and shorter postoperative length of stay compared with surgery, but surgery had higher curability than percutaneous transcatheter embolization. Surgery may be considered as a therapeutic option for patients with lesions that can be completely resected and are difficult to treat with percutaneous transcatheter embolization.

Coil Intrabronchial Migration in an Arteriovenous Malformation Patient Treated 10 Years Ago

A 56-year-old male who had received transcatheter coil deposition 10 years ago for an arteriovenous malformation (AVM) was admitted to our hospital because of persistent hemosputum. Chest radiograph and bronchoscopy revealed straightened coil bundles in his air way. Recently, less invasive transcatheter intervention has been performed more frequently for treatment of AVM than surgical resection. In our case, however, chest radiography and bronchoscopy showed that the coils might migrate from the deposited site to the airway. Then, right lower lobectomy was undertaken. In AVM patient who received coil deposition, a long-term follow-up is recommended, and surgical resection should be carried out if necessary.

Pulmonary arteriovenous malformations: evidence of physician under-education

Pulmonary arteriovenous malformations (PAVMs) are abnormal blood vessels that connect pulmonary arteries direct to pulmonary veins, thus bypassing the pulmonary capillaries which are essential to filter, process and oxygenate blood [1]. Population-wide screening programmes using thoracic computed tomography scans suggest a prevalence of 1 in 2630 (95% CI 1 in 1315–1 in 5555) [2], although the condition is subject to substantial under-ascertainment [3].

PAVMs pose unique management challenges; publication patterns indicate their importance remains poorly recognisedhttp://ow.ly/7iIT304WYl2

Pulmonary shunts in severe hepatosplenic schistosomiasis: Diagnosis by contrast echocardiography and their relationship with abdominal ultrasound findings

Background

Schistosomiasis is endemic to several parts of the world. Among the species that affect humans, Schistosoma mansoni is one of the most common causes of illness. In regions where schistosomiasis mansoni is endemic, reinfection is responsible for the emergence of hepatosplenic schistosomiasis (HSS) with portal hypertension in about 10% of infected individuals. Regardless of its etiology, portal hypertension may bring about the formation of arteriovenous fistulas and pulmonary vascular dilation, thus constituting a pulmonary shunt and its presence has been associated with the occurrence of neurological complications. The objective of this study was to identify pulmonary shunt using TTCE in patients with HSS and esophageal varices, and to compare the abdominal ultrasound and endoscopy findings among patients with and without pulmonary shunt.

Methodology/Principal findings

In this case series, a total of 461 patients with schistosomiasis mansoni were prospectively evaluated using abdominal ultrasound and endoscopy and 71 presented with HSS with esophageal varices. Fifty seven patients remained in the final analysis. The mean age of the patients was 55 ± 14 years, and 65% were female. Pulmonary shunts were observed in 19 (33.3%) patients. On comparing the groups with and without pulmonary shunt, no significant differences were observed in relation to the abdominal ultrasound and endoscopic findings. When comparing the two subgroups with pulmonary shunts (grade 1 vs grades 2 and 3), it was observed that the subgroup with shunt grades 2 and 3 presented with a significantly higher frequency of an enlarged splenic vein diameter (>0.9 cm), and an advanced pattern of periportal hepatic fibrosis (P = 0.041 and P = 0.005, respectively). None of the patients with pulmonary shunts had severe neurological complications.

Conclusions/Significance

Our findings suggest that in HSS with esophageal varices the pulmonary shunts may be present in higher grades and that in this condition it was associated with ultrasound findings compatible with advanced HSS.

Among the species of Schistosoma that infect humans Schistosoma mansoni is one of the most common causes of illness. In the areas where schistosomiasis mansoni is endemic, around 10% of infected individuals develop hepatosplenic schistosomiasis (HSS) with portal hypertension. Portal hypertension may promotes an imbalance in the hepatic production of vasoactive substances, which may act on the lungs promoting the formation of arteriovenous fistulas and pulmonary vascular dilation, a condition that is called a pulmonary shunt. When the pulmonary shunt is of higher grades, small thrombus or septic emboli that would normally be filtered through the pulmonary capillaries reach the left heart and the systemic circulation, which can lead to neurological complications. We found pulmonary shunts in patients with HSS and esophageal varices and we also found that patients with higher grades of pulmonary shunts presented with a significantly higher frequency of advanced periportal fibrosis and an enlarged splenic vein diameter. No neurological complications were observed. Our findings suggest that pulmonary shunts may be present in patients with HSS and esophageal varices. The abdominal ultrasound findings compatible with advanced HSS could be used as screening to investigate pulmonary shunt.

A case of sulfhemoglobinemia in a child with chronic constipation

Sulfhemoglobinemia is a rare condition in which a sulfur atom oxidizes the heme moiety in hemoglobin, making the hemoglobin incapable of carrying oxygen and leading to hypoxia and cyanosis.

This condition has been described in patients taking sulfur medications or who have cultured hydrogen sulfide producing intestinal bacteria such as Morganella morganii. This case describes a pediatric patient who was found to have cyanosis on two occasions of urinary tract infection in the setting of chronic constipation, with confirmed sulfhemoglobinemia during the second admission. Sulfhemoglobinemia due to increases in sulfur producing intestinal bacteria led to cyanosis and low oxygen saturations. The patient had an incidental finding of a pulmonary arteriovenous malformation (AVM) but had a normal PAO2 so was not hypoxemic though she was cyanotic. Low oxygen saturations by pulse oximetry may be explained by dyshemoglobinemia as opposed to true arterial hypoxemia; the importance of measuring an arterial blood gas in cases of cyanosis is paramount.

Surgical treatment of pulmonary arteriovenous malformations

BACKGROUND/AIM

Pulmonary arteriovenous malformations (PAVMs) are direct communications between the branches of pulmonary arteries and veins. This study evaluates surgically treated cases of pulmonary arteriovenous malformations.

MATERIALS AND METHODS

We retrospectively examined 41 cases of PAVM that were operated in our clinic between 1995 and 2012. We obtained the clinical, radiological, and surgical data of the patients from their files.

RESULTS

The 41 cases comprised 27 males and 14 females. Their mean age at diagnosis was 39.8 years (range: 9-71). The symptoms were hemoptysis in 28 cases, dyspnea in five, cough in three, and epistaxis in two; three patients were asymptomatic. Twenty-three right and 19 left posterolateral thoracotomies were performed, including one case which was operated bilaterally. Lower lobectomy was performed in 17 patients, lower lobectomy and lingulectomy in two, upper lobectomy in ten, middle lobectomy in two, segmentectomy in seven, and wedge resection in four. Postoperative histopathology was arteriovenous malformation in all cases.

CONCLUSION

PAVMs are rare clinical conditions. Surgery remains the first choice when embolization treatment cannot be performed or is not successful, in symptomatic and complicated patients with PAVM, and/or in cases where the PAVM diagnosis cannot be established.

Hereditary Hemorrhagic Telangiectasia and Myocardial Infarction

Hereditary hemorrhagic telangiectasia, also known as Osler-Weber-Rendu syndrome, is an autosomal dominant genetic disorder that leads to epistaxis, gastrointestinal bleeding, iron deficiency anemia, and arteriovenous malformations at the lungs, the liver, and the brain. However, due to its rarity and its unspecific findings on routine examinations, diagnosis is not easy unless suspected due to hypoxemia or paradoxical embolism. We present a case of a 46-year-old-woman with hereditary hemorrhagic telangiectasia and hypoxemia who presented a myocardial infarction secondary to paradoxical embolism through pulmonary arteriovenous malformations.

A case of prenatally diagnosed extrapulmonary arteriovenous malformation associated with a complex heart defect

Pulmonary arteriovenous malformations are rare vascular anomalies of the lung, only a few cases of which have been diagnosed prenatally. The diagnostic clue for prenatal diagnosis was cardiomegaly with a particularly enlarged left atrium. All previous cases of pulmonary arteriovenous malformations diagnosed prenatally have been reported as an isolated anomaly or in association with simple heart defects. We here describe the first case of a pulmonary arteriovenous malformation with a complex heart defect that was diagnosed prenatally at 21.0 weeks of gestation and confirmed by postmortem autopsy.

Birt-Hogg-Dube syndrome accompanied by pulmonary arteriovenous malformation

A 25-year-old male with Birt-Hogg-Dube (BHD) syndrome who developed hemothorax caused by ruptured of pulmonary arteriovenous malformation was reported. The patient was admitted to the hospital due to chest pain. A chest X-ray showed pleural fluid in his left lung, and a chest CT showed the presence of a tumor with enhanced contrast in the lower left lobe of approximately 5 cm in a diameter. Pleural fluid was collected by tap and indicated the presence of blood; therefore, hemothorax was suspected. Thoracoscopic surgery was performed to remove the mass for homostasis. Pathological findings indicated that the resected tumor-like lesion was an intrapulmonary hematoma, and aggregated vascular vessels of various diameters forming incomplete media elastic lamina was observed around the hematoma; therefore, it was diagnosed as pulmonary arteriovenous malformation. Family history of the patient indicated the presence of pneumothorax and malignant diseases, and the patient presented with papules and multiple pulmonary cysts. The genetic test revealed a deletion of exon 11 of the BHD gene; therefore, the patient was diagnosed with BHD syndrome. This report is the first to describe BHD syndrome accompanied by pulmonary arteriovenous malformation.

Exercise-induced bronchoconstriction update-2016

The first practice parameter on exercise-induced bronchoconstriction (EIB) was published in 2010. This updated practice parameter was prepared 5 years later. In the ensuing years, there has been increased understanding of the pathogenesis of EIB and improved diagnosis of this disorder by using objective testing. At the time of this publication, observations included the following: dry powder mannitol for inhalation as a bronchial provocation test is FDA approved however not currently available in the United States; if baseline pulmonary function test results are normal to near normal (before and after bronchodilator) in a person with suspected EIB, then further testing should be performed by using standardized exercise challenge or eucapnic voluntary hyperpnea (EVH); and the efficacy of nonpharmaceutical interventions (omega-3 fatty acids) has been challenged. The workgroup preparing this practice parameter updated contemporary practice guidelines based on a current systematic literature review. The group obtained supplementary literature and consensus expert opinions when the published literature was insufficient. A search of the medical literature on PubMed was conducted, and search terms included pathogenesis, diagnosis, differential diagnosis, and therapy (both pharmaceutical and nonpharmaceutical) of exercise-induced bronchoconstriction or exercise-induced asthma (which is no longer a preferred term); asthma; and exercise and asthma. References assessed as relevant to the topic were evaluated to search for additional relevant references. Published clinical studies were appraised by category of evidence and used to document the strength of the recommendation. The parameter was then evaluated by Joint Task Force reviewers and then by reviewers assigned by the parent organizations, as well as the general membership. Based on this process, the parameter can be characterized as an evidence- and consensus-based document.

Pulmonary arteriovenous malformation in chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension is a morbid condition associated with complications such as hemoptysis, right heart failure, paradoxical embolism, and even death. There is no known association of chronic thromboembolic pulmonary hypertension with pulmonary arteriovenous malformation. Possible hypothesis for this association is an increased pulmonary vascular resistance leading to the compensatory formation of pulmonary arteriovenous malformation. We present one such case presenting with hemoptysis that was managed with endovascular treatment.

Idiopathic pulmonary malformation: A case report

Background:

Pulmonary arteriovenous malformations have been associated with clinical situations that put life at risk or cause physical disability. When the clinical picture is evident, percutaneous occlusion is recommended.

Methods:

We describe the use of an Amplatzer vascular plug in a female patient for the treatment of an idiopathic pulmonary arteriovenous malformation associated with syncope and transient ischemic attacks.

Results:

The patient was successfully treated via percutaneous intervention without complications. At 6 months follow-up, there was an absence of the pulmonary arteriovenous malformation confirmed via angiotomography and a full reintegration into her daily activities with no-clinical eventualities.

Conclusion:

The use of an Amplatzer vascular plug should be considered for the treatment of idiopathic pulmonary arteriovenous malformation. In experienced centers the procedure can be done safely with excellent clinical outcomes.

Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is an underrecognized and underdiagnosed autosomal-dominant angiodysplasia that has an estimated prevalence of 1 in 5000 individuals, with variable clinical presentations even within family members with identical mutations. The most common manifestations are telangiectasias of the skin and nasal mucosa. However, HHT can often be complicated by the presence of arteriovenous malformations and telangiectasias in the lungs, brain, gastrointestinal tract, and liver that are often silent and can lead to life-threatening complications of stroke and hemorrhage. This article reviews HHT for the pulmonologist, who is not uncommonly the first practitioner to encounter these patients.

Follow-up of pulmonary right-to-left shunt in hereditary haemorrhagic telangiectasia

Pulmonary arteriovenous malformations (PAVMs) are associated with severe neurological complications in hereditary haemorrhagic telangiectasia (HHT). Transthoracic contrast echocardiography (TTCE) is recommended for screening of pulmonary right-to-left shunts (RLS). Although growth of PAVMs is shown in two small studies, no studies on follow-up with TTCE exist.All HHT patients underwent a second TTCE 5 years after initial screening. Patients with a history of PAVM embolisation were excluded. Pulmonary RLS grade on TTCE after 5 years was compared to the grade at screening.200 patients (53.5% female, mean±sd age at screening 44.7±14.1 years) were included. Increase in RLS grade occurred in 36 (18%) patients, of whom six (17%) underwent embolisation. The change in grade between screening and follow-up was not more than one grade. Of patients with nontreatable pulmonary RLS at screening (n=113), 14 (12.4%) underwent embolisation. In patients without pulmonary RLS at initial screening (n=87), no treatable PAVMs developed during follow-up.Within 5 years, no treatable PAVMs developed in HHT patients without pulmonary RLS at initial screening. Increase in pulmonary RLS grade occurred in 18% of patients, and never increased by more than one grade. Of patients with nontreatable pulmonary RLS at initial screening, 12% underwent embolisation.

Review of diagnostic uses of shunt fraction quantification with technetium-99m macroaggregated albumin perfusion scan as illustrated by a case of Osler-Weber-Rendu syndrome

Bilateral pulmonary arteriovenous malformations (AVMs) are rare and are often associated with the hereditary hemorrhagic telangiectasia (HHT/Osler–Weber–Rendu) syndrome. We present a woman who presented with neurological symptoms due to a cerebral abscess. On further evaluation, bilateral pulmonary AVMs were identified. The patient was diagnosed with HHT, based on positive family history and multiple cerebral AVMs recognized on subsequent catheter angiogram, in addition to the presence of bilateral pulmonary AVMs. Craniotomy with drainage of the brain abscess and endovascular embolization of the pulmonary AVMs was offered to the patient. As a preembolization work-up, the patient underwent nuclear lung perfusion scan with technetium-99m macroaggregated albumin (Tc-99m MAA) to assess the right-to-left shunt secondary to the pulmonary AVMs. Postembolization follow-up perfusion scan was also obtained to estimate the hemodynamic response. The case is presented to describe the role of Tc-99m MAA perfusion lung scan in preoperatively evaluating patients with pulmonary AVMs and to emphasize on the scan's utility in posttreatment follow-up. Various present day usages of the Tc-99m MAA lung perfusion scan, other than diagnosing pulmonary thromboembolism, are discussed. Providing background knowledge on the physiological and hemodynamic aspects of the Tc-99m MAA lung perfusion scan is also attempted. Various imaging pitfalls and necessary precautions while performing Tc-99m MAA lung perfusion scan are highlighted.

Pulmonary Arteriovenous Fistula: Clinical and Histologic Spectrum of Four Cases

Pulmonary arteriovenous fistula (PAVF) is abnormally dilated vessels that provide a right-to-left shunt between pulmonary artery and pulmonary vein and is clinically divided into simple and complex type. Here, we report four cases of surgically resected sporadic PAVFs presenting various clinical and histologic spectrums. Cases 1 (a 57-old-female) and 2 (a 54-old-female) presented as incidentally identified single aneurysmal fistulas and the lesions were surgically removed without complication. On the other hand, case 3 (an 11-old-male) showed diffuse dilated vascular sacs involving both lungs and caused severe hemodynamic and pulmonary dysfunction. Embolization and surgical resection of the main lesion failed to relieve the symptoms. Case 4 (a 36-old-male) had a localized multiloculated cyst clinically mimicking congenital cystic adenomatoid malformation. Microscopically, the lesion consisted of dilated thick vessels, consistent with the diagnosis of fistulous arteriovenous malformation/hemangioma.

Usefulness of Transcranial Doppler for Detecting Pulmonary Arteriovenous Malformations in Hereditary Hemorrhagic Telangiectasia

The aim of this study was to assess transcranial Doppler (TCD) as a screening test for pulmonary arteriovenous malformation (PAVM) in patients with hereditary hemorrhagic telangiectasia (HHT). This retrospective study included suspected patients with HHT who were screened for PAVM with a TCD and a chest computed tomography (CT) study. The results of TCD and CT were compared to evaluate the usefulness of TCD for detecting PAVM. A TCD Spencer grade ≥3 was defined as positive for a significant right-to-left shunt (RLS). The diameter of the pulmonary arteries feeding the PAVM was measured by calipers from the CT study. In 86 subjects from 74 families with HHT, the sensitivity of TCD for identifying a PAVM at rest was 98% and post-Valsalva was 100%. Specificity was 58% and 35%, respectively, presumably due to pulmonary shunts too small to recognize on CT. Of the patients with HHT who were referred for embolization therapy for their PAVMs, all 20 had TCD grade ≥3. In patients who were diagnosed with a PAVM by chest CT, patients with TCD grade ≥5 had a significantly larger sum of artery diameters feeding the PAVMs compared to those with grade ≤4 (5.0 ± 3.2 mm vs 2.6 ± 1.9 mm, p = 0.01). In conclusion, a TCD examination for evaluating RLS is sensitive for identifying PAVM in patients with HHT and is useful in quantitating the degree of RLS flow. The sensitivity of the TCD examination makes it a useful screening test without radiation in HHT subjects to determine which patients need to undergo CT evaluation to identify PAVMs.

Diffuse Pulmonary Arteriovenous Fistulas With Pulmonary Arterial Hypertension: Case Report and Review

Pulmonary arteriovenous fistulas (PAVFs) are rare. Diffuse type PAVFs with pulmonary arterial hypertension (PAH) are even rarer and can elude anatomy imaging like a plain chest film or a computed tomography. The rapid blood flow that ensues due to lack of a capillary bed leads to various degrees of ischemia depending on the number and size of the PAVF. This is a case report of diffuse PAVF in a patient with PAH.This case report describes a patient with recurrent hemoptysis and chest pain. Systemic examination was unremarkable except for P2 attenuation on auscultation. Echocardiograghy showed confirmed pulmonary hypertension with mild dilation of right atrium and ventricle and a tricuspid regurgitation pressure gradient of 40 mm Hg and ruled out congenital heart diseases. Right heart catheterization revealed precapillary PAH with mean pulmonary arterial pressure of 88 mm Hg. Pulmonary angiography showed enlarged pulmonary arterial trunk and diffuse spiral tortuous pulmonary arterial branches indicting diffuse PAVFs. The patient was diagnosed as PAH and began treatment of 25 mg tid of sildenafil.The case highlights a rare and unique presentation of PAH.

Pulmonary Arteriovenous Malformations and Risk of Stroke

Pulmonary arteriovenous malformations (PAVMs) are rare, with an estimated incidence of 2 to 3 cases per 100,000, with most PAVMs (50%-80%) occurring in patients with hereditary hemorrhagic telangiectasia. Hypoxemia and orthodeoxia are some of the more common clinical presentations. The estimated risk of stroke secondary to PAVMs is as high as 2.6% to 25.0%. A combination of chest radiograph and contrast echocardiography is a good screening evaluation in patients with suspected PAVMs. Transcatheter therapy is the most suitable therapeutic option in most patients with PAVMs, and a variety of devices can be used to occlude the PAVMs.

Feasibility of Non-contrast-enhanced MR Angiography Using the Time-SLIP Technique for the Assessment of Pulmonary Arteriovenous Malformation

Purpose:

The purpose of this study was to evaluate the diagnostic performance of non-contrast-enhanced magnetic resonance angiography with time-spatial labeling inversion pulse (time-SLIP MRA) in the assessment of pulmonary arteriovenous malformation (PAVM).

Methods:

Eleven consecutive patients with 38 documented PAVMs underwent time-SLIP MRA with a 3-tesla unit. Eight patients with 25 lesions were examined twice, once before and once after embolotherapy. The lesions were divided into two groups—initial diagnosis (n = 35) and follow-up (n = 28)—corresponding to untreated and treated lesions, respectively, and were evaluated separately. To evaluate the initial diagnosis group, two reviewers assessed image quality for visualization of PAVMs by using a qualitative 4-point scale (1 = not assessable to 4 = excellent). The location and classification of PAVMs were also evaluated. The results were compared with those from digital subtraction angiography. For evaluation of the follow-up group, the reviewers assessed the status of treated PAVMs. Reperfusion and occlusion were defined respectively as visualization or disappearance of the aneurysmal sac. The diagnostic accuracy of time-SLIP MRA was assessed and compared with standard reference images. Interobserver agreement was evaluated with the κ statistic.

Results:

In the initial diagnosis group, time-SLIP MRA correctly determined the PAVMs in all but one patient with one lesion who had image degradation due to irregular breath. Image quality was considered excellent (median = 4) and the κ coefficient was 0.85. Additionally, both readers could correctly localize and classify the PAVMs on time-SLIP MRA images with both κ coefficient of 1.00. In the follow-up group, the sensitivity and specificity of time-SLIP MRA for reperfusion of PAVMs were both 100%, and the κ coefficient was 1.00.

Conclusion:

Time-SLIP MRA is technically and clinically feasible and represents a promising technique for noninvasive pre- and post-treatment assessment of PAVMs.

Regression of a Pulmonary Arteriovenous Malformation after Acute Interstitial Nephritis

A 68-year-old woman was scheduled to undergo percutaneous embolization of a pulmonary arteriovenous malformation (PAVM) to prevent a paradoxical embolic event. After contrast-enhanced computed tomography (CT) was performed to carefully evaluate the PAVM, she developed acute interstitial nephritis, which required steroid therapy. Moreover, her D-dimer level increased, which was suggestive of thrombus formation. After nine months, we noted that the affected vessels had markedly decreased in size, and the fistula had almost disappeared on unenhanced CT images. To our knowledge, this is the first case report to describe the regression of a PAVM, detected by CT, after the onset of acute interstitial nephritis.

Pulmonary vascular complications of hereditary haemorrhagic telangiectasia

PURPOSE OF REVIEW

The purpose of this study is to present the latest advances and recommendations in the diagnosis and treatment of pulmonary vascular complications associated with hereditary haemorrhagic telangiectasia (HHT): pulmonary arteriovenous malformations (PAVMs), pulmonary arterial hypertension (PAH), pulmonary hypertension associated with high output cardiac failure or liver vascular malformations, haemoptysis, haemothorax and thromboembolic disease.

RECENT FINDINGS

Transthoracic contrast echocardiography has been validated as a screening tool for PAVM in patients with suspected HHT. Advancements in genetic testing support its use in family members at risk as a cost-effective measure. Therapy with bevacizumab in patients with high output cardiac failure and severe liver AVMs showed promising results. PAH tends to be more aggressive in HHT type 2 patients.

SUMMARY

Patients suffering from this elusive disease should be referred to HHT specialized centres to ensure a standardized and timely approach to diagnosis and management.

Diagnosis and management of hemoptysis

Hemoptysis is the expectoration of blood that originates from the lower respiratory tract. It is usually a self-limiting event but in fewer than 5% of cases it may be massive, representing a life-threatening condition that warrants urgent investigations and treatment. This article aims to provide a comprehensive literature review on hemoptysis, analyzing its causes and pathophysiologic mechanisms, and providing details about anatomy and imaging of systemic bronchial and nonbronchial arteries responsible for hemoptysis. Strengths and limits of chest radiography, bronchoscopy, multidetector computed tomography (MDCT), MDCT angiography and digital subtraction angiography to assess the cause and lead the treatment of hemoptysis were reported, with particular emphasis on MDCT angiography. Treatment options for recurrent or massive hemoptysis were summarized, highlighting the predominant role of bronchial artery embolization. Finally, a guide was proposed for managing massive and nonmassive hemoptysis, according to the most recent medical literature.

Intrapulmonary arteriovenous malformation causing recurrent strokes

This case reveals a left pulmonary arteriovenous malformation (PAVM) as a cause of recurrent cerebral and cerebellar emboli. Extensive workup excluded other etiologies of emboli formation, and the patient was transferred to a tertiary care center for percutaneous embolotherapy. In the absence of a clear etiology, PAVM should be considered as a potential cause of recurrent cerebral emboli, especially in the absence of carotid disease, intracardiac thrombus, atrial septal defect, and patent foramen ovale. Diagnostic work-up for the PAVM can be cost effective and expedited by utilization of agitated saline contrast echocardiography, as noted in our case.

Device closure of pulmonary arteriovenous malformation using Amplatzer vascular plug II in hereditary hemorrhagic telangiectasia

Pulmonary arteriovenous malformations (AVM) are very rare and carry the risk of cerebral thrombo-embolism, brain abscess or pulmonary hemorrhage. The Amplatzer vascular plug II (AVP II) is a new device, used for embolization of the pulmonary AVMs. We report a case of pulmonary AVM successfully managed by using AVP II in a patient with hereditary hemorrhagic telangiectasia (HHT).

Successful Treatment of a Large Pulmonary Arteriovenous Malformation by Repeated Coil Embolization

Pulmonary arteriovenous malformations (AVMs) are caused by abnormal vascular communications between the pulmonary arteries and pulmonary veins, which lead to the blood bypassing the normal pulmonary capillary beds. Pulmonary AVMs result in right-to-left shunts, resulting in hypoxemia, cyanosis, and dyspnea. Clinical signs and symptoms vary depending on the size, number, and flow of the AVMs. Transcatheter embolization is the treatment of choice for pulmonary AVMs. However, this method can fail if the AVM is large or has multiple complex feeding arteries. Surgical resection is necessary in those kind of cases. Here, we report the case of a patient with a 6-cm pulmonary AVM with multiple feeding arteries that was successfully treated by repeated coil embolization without surgery.