Sudden pediatric death unveiling pulmonary arteriovenous malformations

Pulmonary arteriovenous malformations (PAVMs) are abnormal vascular connections between pulmonary arteries and veins, often associated with hereditary hemorrhagic telangiectasia (HHT). Most PAVMs are asymptomatic, but life-threatening complications like pulmonary hemorrhage, brain abscesses, and paradoxical emboli can emerge, so prompt diagnosis and treatment are crucial. We report a case of sudden pediatric death in a two-year-old female with no past medical history. Initial vomiting and fast deterioration resulted in a sudden cardiac arrest. The postmortem examination found histological evidence of consistent, extensive lung damage. The absence of the characteristic symptoms made for some challenges when it came to diagnosis, showing precisely that in early life, you could well have many difficulties in catching PAVMs. This case highlights the need to take PAVMs into account as a potential cause of sudden death, particularly when there are no conspicuous symptoms. Awareness among forensic pathologists and consideration of genetic analysis for HHT in such cases is crucial for accurate diagnosis and management.

The role of interventional radiology in treatment of patients with hereditary hemorrhagic telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) also known as Osler-Weber-Rendu disease is a rare autosomal dominant, multi-organ disorder that leads to formation of abnormal vascular connections resulting in devastating and life-threatening complications. Due to its multisystem character, wide range of clinical manifestations and variable expressivity, HHT remains a diagnostic challenge and requires close cooperation of specialists from various medical fields. Interventional radiology plays a key role in the management of this disease, helping maintain the health of HHT patients and minimize the risk of fatal complications. The aim of this article is to review clinical manifestations, diagnostic guidelines and criteria of HHT as well as to present the means of endovascular therapy in the management of HHT patients.

Diagnosis and Management of Persistent Pulmonary Arterio-venous Malformations following Embolotherapy

Embolotherapy is the primary treatment for pulmonary arterio-venous malformations (PAVMs). Approximately, 2-25% of PAVMs demonstrate persistence following embolization. Early identification and treatment of persistent PAVMs are critical to mitigating life threatening complications. The presence of prior embolic devices and complex angioarchitecture of persistent PAVMs pose technical challenges during repeat embolotherapy. In this article, we review patterns of persistence, factors affecting the persistence, endovascular treatment techniques, and outcomes.

Update on pulmonary arteriovenous malformations

This review aimed to provide an overview of pulmonary arteriovenous malformations, including the major clinical and radiological presentations, investigation, and treatment algorithm of the condition. The primary etiology of pulmonary arteriovenous malformations is hereditary hemorrhagic telangiectasia (HHT), also known as Rendu-Osler-Weber syndrome, with mutations in the ENG gene on chromosome 9 (HHT type 1) or in the ACVRL1/ALK1 complex (HHT type 2). Epistaxis should always be evaluated when repeated, when associated with anemia, and in some cases of hypoxemia. In the investigation, contrast echocardiography and chest CT are essential for evaluating this condition. Embolization is the best treatment choice, especially for correction in cases of hypoxemia or to avoid systemic infections. Finally, disease management was addressed in special conditions such as pregnancy. CT follow-up should be performed every 3-5 years, depending on the size of the afferent and efferent vessels, and antibiotic prophylactic care should always be oriented. Ultimately, knowledge of the disease by health professionals is a crucial point for the early diagnosis of these patients in clinical practice, which can potentially modify the natural course of the disease.

Feasibility of Single-Shot Whole Thoracic Time-Resolved MR Angiography to Evaluate Patients with Multiple Pulmonary Arteriovenous Malformations

OBJECTIVE

To evaluate the feasibility of single-shot whole thoracic time-resolved MR angiography (TR-MRA) to identify the feeding arteries of pulmonary arteriovenous malformations (PAVMs) and reperfusion of the lesion after embolization in patients with multiple PAVMs.

MATERIALS AND METHODS

Nine patients (8 females and 1 male; age range, 23-65 years) with a total of 62 PAVMs who underwent percutaneous embolization for multiple PAVMs and were subsequently followed up using TR-MRA and CT obtained within 6 months from each other were retrospectively reviewed. All imaging analyses were performed by two independent readers blinded to clinical information. The visibility of the feeding arteries on maximum intensity projection (MIP) reconstruction and multiplanar reconstruction (MPR) TR-MRA images was evaluated by comparing them to CT as a reference. The accuracy of TR-MRA for diagnosing reperfusion of the PAVM after embolization was assessed in a subgroup with angiographic confirmation. The reliability between the readers in interpreting the TR-MRA results was analyzed using kappa (κ) statistics.

RESULTS

Feeding arteries were visible on the original MIP images of TR-MRA in 82.3% (51/62) and 85.5% (53/62) of readers 1 and 2, respectively. Using the MPR, the rates increased to 93.5% (58/62) and 95.2% (59/62), respectively (κ = 0.760 and 0.792, respectively). Factors for invisibility were the course of feeding arteries in the anteroposterior plane, proximity to large enhancing vessels, adjacency to the chest wall, pulsation of the heart, and small feeding arteries. Thirty-seven PAVMs in five patients had angiographic confirmation of reperfusion status after embolization (32 occlusions and 5 reperfusions). TR-MRA showed 100% (5/5) sensitivity and 100% (32/32, including three cases in which the feeding arteries were not visible on TR-MRA) specificity for both readers.

CONCLUSION

Single-shot whole thoracic TR-MRA with MPR showed good visibility of the feeding arteries of PAVMs and high accuracy in diagnosing reperfusion after embolization. Single-shot whole thoracic TR-MRA may be a feasible method for the follow-up of patients with multiple PAVMs.

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.

Incidence of Spontaneous Pulmonary AVM Rupture in HHT Patients

The spontaneous rupture of pulmonary AVMs, resulting in pulmonary hemorrhage and hydrothorax, is a life-threatening complication. While this phenomenon has been previously reported, the true incidence is not yet known. This study retrospectively reviewed records of 801 HHT patients with pulmonary AVMs to identify a single lifetime episode of hemothorax or pulmonary hemorrhage secondary to pulmonary AVM rupture. The lifetime prevalence and incidence of pulmonary AVM rupture in HHT patients was 2.7% and 0.16% respectively. In these patients, AVM rupture represented the initial presentation of HHT in nine (40.9%) cases and was life-threatening in nine (40.9%) cases. All cases occurred in virgin lesions, and subsequent embolization was curative. While a feared complication, pulmonary AVM rupture is rare and is likely effectively prevented by existing embolization techniques and indications.

Massive haemorrhagic complications of ruptured pulmonary arteriovenous malformations: outcomes from a 12 years' retrospective study

Background

The life-threatening haemorrhagic complications of pulmonary arteriovenous malformations (PAVMs) are extremely rare, and only described in isolated cases. This study was designed to comprehensively investigate management of ruptured PAVMs.

Methods

We retrospectively assessed clinical and imaging data of ruptured PAVMs to summarize incidence, clinical characteristics, and outcomes following embolisation between January 2008 and January 2021.

Results

Eighteen of 406 (4.4%) patients with PAVMs developed haemorrhagic complications. Twelve of 18 patients were clinically diagnosed with hereditary haemorrhagic telangiectasia (HHT). Haemorrhagic complications occurred with no clear trigger in all cases. Eight of 18 patients (44.4%) were initially misdiagnosed or had undergone early ineffective treatment. 28 lesions were detected, with 89.3% of them located in peripheral lung. Computed tomography angiography (CTA) showed indirect signs to indicate ruptured PAVMs in all cases. Lower haemoglobin concentrations were associated with the diameter of afferent arteries in the ruptured lesions. Successful embolotherapy was achieved in all cases. After embolotherapy, arterial oxygen saturation improved and bleeding was controlled (P < 0.05). The mean follow-up time was 3.2 ± 2.5 years (range, 7 months to 10 years).

Conclusions

Life threatening haemorrhagic complications of PAVMs are rare, they usually occur without a trigger and can be easily misdiagnosed. HHT and larger size of afferent arteries are major risk factors of these complications. CTA is a useful tool for diagnosis and therapeutic guidance for ruptured PAVMs. Embolotherapy is an effective therapy for this life-threatening complication.

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.

Endovascular Repair of Diffuse Pulmonary Arteriovenous Malformations with Systemic Arterial Shunts

Diffuse pulmonary arteriovenous malformations (PAVMs) are defined as arteriovenous malformations (AVMs) involving subsegmental, segmental, or both types of arteries in at least 1 lung lobe and are more extensive than multiple PAVMs. Diffuse PAVMs involving systemic arterial shunts are very rare. We describe a rare case, in which diffuse PAVMs involving systemic arterial shunts were successfully treated with coil embolization.

Predictors of mortality in patients with hereditary hemorrhagic telangiectasia

Background

Retrospective questionnaire and healthcare administrative data suggest reduced life expectancy in untreated hereditary hemorrhagic telangiectasia (HHT). Prospective data suggests similar mortality, to the general population, in Denmark’s centre-treated HHT patients. However, clinical phenotypes vary widely in HHT, likely affecting mortality. We aimed to measure predictors of mortality among centre-treated HHT patients. HHT patients were recruited at 14 HHT centres of the Brain Vascular Malformation Consortium (BVMC) since 2010 and followed annually. Vital status, organ vascular malformations (VMs) and clinical symptoms data were collected at baseline and during follow-up (N = 1286). We tested whether organ VMs, HHT symptoms and HHT genes were associated with increased mortality using Cox regression analysis, adjusting for patient age, sex, and smoking status.

Results

59 deaths occurred over average follow-up time of 3.4 years (max 8.6 years). A history of anemia was associated with increased mortality (HR = 2.93, 95% CI 1.37–6.26, p = 0.006), as were gastro-intestinal (GI) bleeding (HR = 2.63, 95% CI 1.46–4.74, p = 0.001), and symptomatic liver VMs (HR = 2.10, 95% CI 1.15–3.84, p = 0.015). Brain VMs and pulmonary arteriovenous malformations (AVMs) were not associated with mortality (p > 0.05). Patients with SMAD4 mutation had significantly higher mortality (HR = 18.36, 95% CI 5.60–60.20, p < 0.001) compared to patients with ACVRL1 or ENG mutation, but this estimate is imprecise given the rarity of SMAD4 patients (n = 33, 4 deaths).

Conclusions

Chronic GI bleeding, anemia and symptomatic liver VMs are associated with increased mortality in HHT patients, independent of age, and in keeping with the limited treatment options for these aspects of HHT. Conversely, mortality does not appear to be associated with pulmonary AVMs or brain VMs, for which patients are routinely screened and treated preventatively at HHT Centres. This demonstrates the need for development of new therapies to treat chronic anemia, GI bleeding, and symptomatic liver VMs in order to reduce mortality among HHT patients.

Approach to Pulmonary Arteriovenous Malformations: A Comprehensive Update

Pulmonary arteriovenous malformations (PAVMs) are abnormal direct vascular communications between pulmonary arteries and veins which create high-flow right-to-left shunts. They are most frequently congenital, usually in the setting of hereditary hemorrhagic telangiectasia (HHT). PAVMs may be asymptomatic or present with a wide variety of clinical manifestations such as dyspnea, hypoxemia, or chest pain. Even when asymptomatic, presence of PAVMs increases patients' risk of serious, potentially preventable complications including stroke or brain abscess. Transcatheter embolotherapy is considered the gold standard for treatment of PAVMs. Though previous guidelines have been published regarding the management of PAVMs, several aspects of PAVM screening and management remain debated among the experts, suggesting the need for thorough reexamination of the current literature. The authors of this review present an updated approach to the diagnostic workup and management of PAVMs, with an emphasis on areas of controversy, based on the latest literature and our institutional experience.

Hereditary hemorrhagic telangiectasia: how to efficiently detect hepatic abnormalities using ultrasonography

INTRODUCTION

Hereditary hemorrhagic telangiectasia (HHT) is a multiorgan genetic angiodysplastic affection characterized by visceral vascular malformations. It affects mainly the brains, lungs, gastrointestinal tract, and nasal mucosa. Unlike those organs, hepatic involvement, although very frequently occurring, is insufficiently recognized, mainly because of the complex vascular structure of this organ. Thus, treating HHT patients requires a solid understanding of these hepatic anomalies. It is especially important for any general clinicians to be able to recognize clinical findings in HHT, which leads to a high suspicion of HHT and have an index of suspicion for liver abnormalities of HHT. For this purpose, keen awareness of clinical as well as hepatic sonographic (US) findings is paramount.

AIM

The aim of this review is to summarize previously reported findings on the hepatic US through a thorough analysis of related articles, and to (a) determine the role of US in the diagnosis of hepatic involvement in HHT patients and (b) propose the most simple and easy way to detect HHT-related abnormalities during routine US examinations.

CONCLUSION

Hepatic US serves to diagnose the detailed complex hepatic changes typical of HHT, and contributes to increased diagnostic confidence of hepatic changes in HHT patients, with the most simple way not to overlook HHT-related abnormalities being to find hepatic artery dilatation.

Comparison of Ferumoxytol-enhanced MR Angiography and CT Angiography for the Detection of Pulmonary Arteriovenous Malformations in Hereditary Hemorrhagic Telangiectasia: Initial Results

PURPOSE

To perform a preliminary comparison of the sensitivity and positive predictive value of ferumoxytol-enhanced MR angiography with those of CT angiography for detection of pulmonary arteriovenous malformations (AVMs) in hereditary hemorrhagic telangiectasia (HHT).

MATERIALS AND METHODS

Institutional review board approval and informed patient consent were obtained. Ten patients with pulmonary AVMs who had undergone CT of the chest within 12 months underwent MRI of the chest and abdomen with ferumoxytol at 3.0 T at a dose of 4 mg per kilogram of body weight. Consensus review of MR and CT images assessed the presence and characteristics of pulmonary AVMs, image quality, vessel visibility, and artifact grade.

RESULTS

Forty-three AVMs were detected, 13 native and 30 recanalized. Twenty-one AVMs had a feeding artery diameter of greater than 2 mm, of which detection occurred in 19 (at MRI and CT), in two (at MRI only), and zero (at CT only). Twenty-two AVMs had a feeding artery diameter of less than or equal to 2 mm, of which detection occurred in 16 (at MRI and CT), six (at CT only), and zero (at MRI only). For the entire cohort, the sensitivity of ferumoxytol-enhanced MRI using CT as the reference standard was 85.4% (35 of 41), and the positive predictive value was 100% (35 of 35). No significant difference was found between CT and MRI in AVM size, feeding artery and draining vein diameter, and artifact score (P >.05 for all).

CONCLUSION

Initial results suggest that ferumoxytol-enhanced MRI is a feasible alternative to CT for detection of pulmonary AVM in HHT, while avoiding repeated exposure to radiation, nephrotoxic contrast material, or gadolinium-based contrast agent.© RSNA, 2020.

Pulmonary arteriovenous malformations: diagnostic and treatment characteristics

Objective:

To present a case series of pulmonary arteriovenous malformations (PAVMs), describing the main clinical findings, the number/location of pulmonary vascular abnormalities, the clinical complications, and the treatment administered.

Methods:

This was a retrospective observational study evaluating patients with PAVM divided into two groups: hereditary hemorrhagic telangiectasia (HHT); and idiopathic PAVM (iPAVM).

Results:

A total of 41 patients were selected for inclusion, but only 33 had PAVMs. After clinical evaluation, 27 and 6 were diagnosed with HHT and iPAVM, respectively. In the HHT group, the mean age was 49.6 years and 88.9% were female. In that group, 4 patients had an SpO₂ of < 90% and the most common clinical finding was epistaxis. In the iPAVM group, the mean age was 48.1 years and 83.3% were female. In that group, 3 patients had an SpO₂ of < 90%. Computed tomographic pulmonary angiography showed that most of the PAVMs were in the lower lobes: 56.4% in the HHT group and 85.7% in the iPAVM group. Embolization was performed in 23 patients (in both groups). At this writing, 10 patients are scheduled to undergo the procedure. One of the patients who underwent embolization was subsequently referred for pulmonary resection.

Conclusions:

In both of the PAVM groups, there was a predominance of women and of fistulas located in the lower lobes. Few of the patients had respiratory symptoms, and most had an SpO₂ > 90%. The treatment chosen for all patients was percutaneous transcatheter embolization.

Pulmonary arteriovenous malformations

Pulmonary arteriovenous malformation, a condition most commonly associated with hereditary hemorrhagic telangiectasia, is an abnormal communication between the pulmonary artery and pulmonary vein without an intervening capillary communication. Although asymptomatic in ~ 50% individuals, it can present with the dreaded complications of stroke or intracranial abscess in high-risk individuals including pregnant women, if untreated. The mainstay of treatment is now endovascular embolization of the feeding artery which can alleviate the symptoms and prevent these complications. In this review, we describe the pathophysiology, methods of screening, diagnostic workup and treatment of these vascular lesions with a particular focus on the currently used embolization techniques and their outcomes.

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.

Hereditary hemorrhagic telangiectasia and pulmonary arteriovenous malformations: clinical aspects

Hereditary hemorrhagic telangiectasia (HHT) is a genetic disorder of blood vessel formation resulting in mucocutaneous telangiectasias and visceral arteriovenous malformations. Nearly half of patients with HHT will have pulmonary arteriovenous malformations (PAVM) that place them at risk for potentially fatal complications that can occur when blood bypasses the pulmonary capillary circulation or as a result of PAVM rupture. Other manifestations of HHT outside the lung may increase the rate and severity of PAVM complications, creating unique clinical challenges. Management hinges on timely screening and diagnosis, followed by treatment of amenable PAVMs with transcatheter embolization in conjunction with medical management and prophylactic measures to treat and prevent complications. The purpose of this review is to highlight the clinical manifestations of PAVMs specific to patients with HHT and to detail screening and treatment strategies that can reduce the risk of developing life-threatening complications.

Pulmonary arteriovenous malformations: endovascular therapy

Pulmonary arteriovenous malformations (PAVM) are abnormal direct communications between the branches of pulmonary arteries and veins, and are often seen in patients with hereditary hemorrhagic telangiectasia (HHT). If untreated, the right to left shunt can result in symptoms of hypoxemia, paradoxical emboli to the left side circulation, stroke and intracranial abscess. Endovascular therapy is a minimally invasive outpatient based treatment wherein the feeding artery to the PAVM is occluded with coils or plugs or a combination of both and is associated with minimal morbidity and no mortality. In this manuscript, we will review the indications and contraindications for endovascular therapy, pre-procedural work up, procedure technique and variations, complications, and outcomes.

Embolisation for pulmonary arteriovenous malformation

BACKGROUND

Pulmonary arteriovenous malformations are abnormal direct connections between the pulmonary artery and pulmonary vein which result in a right-to-left shunt. They are associated with substantial morbidity and mortality mainly from the effects of paradoxical emboli. Potential complications include stroke, cerebral abscess, pulmonary haemorrhage and hypoxaemia. Embolisation is an endovascular intervention based on the occlusion of the feeding arteries the pulmonary arteriovenous malformations thus eliminating the abnormal right-to-left-shunting. This is an update of a previously published review.

OBJECTIVES

To determine the efficacy and safety of embolisation in patients with pulmonary arteriovenous malformations including a comparison with surgical resection and different embolisation devices.

SEARCH METHODS

We searched the Cystic Fibrosis and Genetic Disorders Group's Trials Register; date of last search: 10 April 2017.We also searched the following databases: the Australian New Zealand Clinical Trials Registry; ClinicalTrials.gov; International Standard Randomised Controlled Trial Number Register; International Clinical Trials Registry Platform Search Portal (last searched 27 August 2017). to be updatedWe checked cross-references and searched references from review articles.

SELECTION CRITERIA

Trials in which individuals with pulmonary arteriovenous malformations were randomly allocated to embolisation compared to no treatment, surgical resection or embolisation using a different embolisation device.

DATA COLLECTION AND ANALYSIS

Studies identified for potential inclusion were independently assessed for eligibility by two authors, with excluded studies further checked by a third author. No trials were identified for inclusion in the review and hence no analysis was performed.

MAIN RESULTS

There were no randomised controlled trials included in the review; one ongoing trial has been identified which may be eligible for inclusion in the future.

AUTHORS' CONCLUSIONS

There is no evidence from randomised controlled trials for embolisation of pulmonary arteriovenous malformations. However, randomised controlled trials are not always feasible on ethical grounds. Accumulated data from observational studies suggest that embolisation is a safe procedure which reduces morbidity and mortality. A standardised approach to reporting with long-term follow-up through registry studies can help to strengthen the evidence for embolisation in the absence of randomised controlled trials.

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.

A tale of two cases of pulmonary arteriovenous malformation: How they fared after cardiac transplantation

BACKGROUND

In single ventricle patients, aortopulmonary collaterals (APCs) and pulmonary arteriovenous malformations (PAVMs) following superior cavopulmonary shunt (CPS) can complicate orthotopic heart transplant (OHT) by cyanosis and hemoptysis. Although PAVMs can regress with the restoration of hepatic venous flow to the pulmonary circulation, the effects of hypoxemia on the "unconditioned" allograft are not known.

CASES

Two patients with significant PAVMs after CPS were cyanotic following OHT. One patient with predominantly unilateral left PAVMs had arterial saturation levels less than 70% despite pulmonary vasodilators and ventilation. A custom flow restrictor-covered stent was deployed in the pulmonary artery of the affected side, redirecting the blood flow to the contralateral lung, immediately improving cyanosis. When the PAVMs regressed, the flow restrictor stent was dilated to eliminate the constriction. The second patient with PAVMs had cyanosis and severe hemoptysis from APCs post-OHT. The APCs required an extensive coil embolization, while the cyanosis responded to oxygen and pulmonary vasodilators. Both recipients did well with gradual resolution of PAVMs within 8 months.

CONCLUSIONS

Despite cyanosis from right-to-left intrapulmonary shunting, allograft function recovered. Novel transcatheter interventions can play a role in patients with significant APCs or PAVM following cardiac transplantation.

Long-term outcomes of patients with pulmonary arteriovenous malformations considered for lung transplantation, compared with similarly hypoxaemic cohorts

INTRODUCTION

Pulmonary arteriovenous malformations (PAVMs) may not be amenable to treatment by embolisation or surgical resection, and many patients are left with significant hypoxaemia. Lung transplantation has been undertaken. There is no guidance on selection criteria.

METHODS

To guide transplantation listing assessments, the outcomes of the six patients who had been considered for transplantation were compared with a similarly hypoxaemic patient group recruited prospectively between 2005 and 2016 at the same UK institution.

RESULTS

Six patients had been formally considered for lung transplantation purely for PAVMs. One underwent a single lung transplantation for diffuse PAVMs and died within 4 weeks of surgery. The other five were not transplanted, in four cases at the patients' request. Their current survival ranges from 16 to 27 (median 21) years post-transplant assessment. Of 444 consecutive patients with PAVMs recruited between 2005 and 2016, 42 were similarly hypoxaemic to the 'transplant-considered' cohort (SaO2 <86.5%). Hypoxaemic cohorts maintained arterial oxygen content (CaO2) through secondary erythrocytosis and higher haemoglobin. The 'transplant-considered' cohort had similar CaO2 to the hypoxaemic comparator group, but higher Medical Research Council (MRC) dyspnoea scores (p=0.023), higher rates of cerebral abscesses (p=0.0043) and higher rates of venous thromboemboli (p=0.0009) that were evident before and after the decision to list for transplantation.

CONCLUSIONS

The non-transplanted patients demonstrated marked longevity. Symptoms and comorbidities were better predictors of health than oxygen measurements. While a case-by-case decision, weighing survival estimates and quality of life will help patients in their decision making, the data suggest a very strong case must be made before lung transplantation is considered.

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 %.

A case of pulmonary arteriovenous malformation: role of interventional radiology in diagnosis and treatment

Pulmonary arterio-venous malformations (PAVMs) are abnormal pulmonary arteries and pulmonary veins communicating directly without interposition of a capillary bed and about 80-90% of patients with PAVMs eventually may present with hereditary hemorrhagic telangiectasia (HHT), remaining ones are sporadic cases. On the other hand, about 15-35% of HHT patients may present with PAVMs. The PAVMs have a tendency to grow and increase in size over time and various factors like puberty, pregnancy and pulmonary arterial hypertension (PAH) affect growth. This condition needs early diagnosis, aggressive management and vigilant follow up. Our article aims to review pulmonary AVMs as a rare cause of strokes in young patients. We will discuss the clinical presentation, diagnosis, complications, the therapeutic options and the follow up.

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.

Endovascular occlusion of pulmonary arteriovenous malformations with the ArtVentive Endoluminal Occlusion System™

Pulmonary arteriovenous malformations (PAVMs) are vascular anomalies of the lung and carry the risk of cerebral thromboembolism, brain abscess, or pulmonary hemorrhage. We describe a 64-year-old male with hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome) who presented with a five-year history of progressive effort dyspnea and a PAVM in the right upper lobe successfully treated by transcatheter embolization of feeding arteries using a new occlusion device, the ArtVentive Endoluminal Occlusion System™.

CT pulmonary angiography of adult pulmonary vascular diseases: Technical considerations and interpretive pitfalls

Computed tomography pulmonary angiography (CTPA) has become the primary imaging modality for evaluating the pulmonary arteries. Although pulmonary embolism is the primary indication for CTPA, various pulmonary vascular abnormalities can be detected in adults. Knowledge of these disease entities and understanding technical pitfalls that can occur when performing CTPA are essential to enable accurate diagnosis and allow timely management. This review will cover a spectrum of acquired abnormalities including pulmonary embolism due to thrombus and foreign bodies, primary and metastatic tumor involving the pulmonary arteries, pulmonary hypertension, as well as pulmonary artery aneurysms and stenoses. Additionally, methods to overcome technical pitfalls and interventional treatment options will be addressed.

Proposed management algorithm for severe hypoxemia after liver transplantation in the hepatopulmonary syndrome

The hepatopulmonary syndrome (HPS) is defined as the triad of liver disease, intrapulmonary vascular dilatation, and abnormal gas exchange, and is found in 10-32% of patients with liver disease. Liver transplantation is the only known cure for HPS, but patients can develop severe posttransplant hypoxemia, defined as a need for 100% inspired oxygen to maintain a saturation of ≥85%. This complication is seen in 6-21% of patients and carries a 45% mortality. Its management requires the application of specific strategies targeting the underlying physiologic abnormalities in HPS, but awareness of these strategies and knowledge on their optimal use is limited. We reviewed existing literature to identify strategies that can be used for this complication, and developed a clinical management algorithm based on best evidence and expert opinion. Evidence was limited to case reports and case series, and we determined which treatments to include in the algorithm and their recommended sequence based on their relative likelihood of success, invasiveness, and risk. Recommended therapies include: Trendelenburg positioning, inhaled epoprostenol or nitric oxide, methylene blue, embolization of abnormal pulmonary vessels, and extracorporeal life support. Availability and use of this pragmatic algorithm may improve management of this complication, and will benefit from prospective validation.

Embolisation for pulmonary arteriovenous malformation

BACKGROUND

Pulmonary arteriovenous malformations are abnormal direct connections between the pulmonary artery and pulmonary vein which result in a right-to-left shunt. They are associated with substantial morbidity and mortality mainly from the effects of paradoxical emboli. Potential complications include stroke, cerebral abscess, pulmonary haemorrhage and hypoxaemia. Embolisation is an endovascular intervention based on the occlusion of the feeding arteries the pulmonary arteriovenous malformations thus eliminating the abnormal right-to-left-shunting.

OBJECTIVES

To determine the efficacy and safety of embolisation in patients with pulmonary arteriovenous malformations including a comparison with surgical resection and different embolisation devices.

SEARCH METHODS

We searched the Cystic Fibrosis and Genetic Disorders Group's Trials Register; date of last search: 31 March 2014.We also searched the following databases: the Australian New Zealand Clinical Trials Registry; ClinicalTrials.gov; International Standard Randomised Controlled Trial Number Register; International Clinical Trials Registry Platform Search Portal (last searched 1 July 2014).We checked cross-references and searched references from review articles.

SELECTION CRITERIA

Trials in which individuals with pulmonary arteriovenous malformations were randomly allocated to embolisation compared to no treatment, surgical resection or embolisation using a different embolisation device.

DATA COLLECTION AND ANALYSIS

Studies identified for potential inclusion were independently assessed for eligibility by two authors, with excluded studies further checked by a third author. No trials were identified for inclusion in the review and hence no analysis was performed.

MAIN RESULTS

There were no randomised controlled trials included in the review; one ongoing trial has been identified which may be eligible for inclusion in the future.

AUTHORS' CONCLUSIONS

There is no evidence from randomised controlled trials for embolisation of pulmonary arteriovenous malformations. However, randomised controlled trials are not always feasible on ethical grounds. Accumulated data from observational studies suggest that embolisation reduces morbidity. A standardised approach to reporting with long-term follow-up through registry studies can help to strengthen the evidence for embolisation in the absence of randomised controlled trials.

Pulmonary arteriovenous malformations

Within the past decade, pulmonary arteriovenous malformations (PAVMs) have evolved from rare curiosities to not uncommon clinical states, with the latest estimates suggesting a prevalence of ~1 in 2,600. PAVMs provide anatomic right-to-left shunts, allowing systemic venous blood to bypass gas exchange and pulmonary capillary bed processing. Hypoxemia and enhanced ventilatory demands result, although both are usually asymptomatic. Paradoxical emboli lead to strokes and cerebral abscesses, and these commonly occur in individuals with previously undiagnosed PAVMs. PAVM hemorrhage is rare but is the main cause of maternal death in pregnancy. PAVM occlusion by embolization is the standard of care to reduce these risks. However, recent data demonstrate that currently recommended management protocols can result in levels of radiation exposure that would be classified as harmful. Recent publications also provide a better appreciation of the hematologic and cardiovascular demands required to maintain arterial oxygen content and oxygen consumption in hypoxemic patients, identify patient subgroups at higher risk of complications, and emphasize the proportion of radiologically visible PAVMs too small to treat by embolization. This review, therefore, outlines medical states that exacerbate the consequences of PAVMs. Chief among these is iron deficiency, which is commonly present due to concurrent hereditary hemorrhagic telangiectasia: iron deficiency impairs hypoxemia compensations by restricting erythropoiesis and increases the risk of ischemic strokes. Management of periodontal disease, dental interventions, pulmonary hypertension, and pregnancy also requires specific consideration in the setting of PAVMs. The review concludes by discussing to what extent previously recommended protocols may benefit from modification or revision.

Regression of pulmonary artery hypertension due to development of a pulmonary arteriovenous malformation

Idiopathic Pulmonary Hypertension (IPAH) is characterized by elevated pulmonary arterial pressure in the absence of an identifiable underlying cause. The condition is usually relentlessly progressive with a short survival in the absence of treatment.(1) We describe a patient of IPAH in whom the pulmonary artery pressures significantly abated with complete disappearance of symptoms, following spontaneous development of a pulmonary arterio-venous malformation (PAVM).

Roles of cyclooxygenase 2 and hepatic venous flow in patients with HHT or hepatopulmonary syndrome

BACKGROUND

Hereditary hemorrhagic telangiectasia (HHT) and hepatopulmonary syndrome are disorders characterized by the development of multiple pulmonary arteriovenous malformations (PAVM).

PRESENTATION OF THE HYPOTHESIS

COX2 may be at the origin of a cascade of pro inflammatory events to favour angiogenesis and PAVM development.

TESTING THE HYPOTHESIS

HHT and hepatopulmonary syndrome mouse models may be used to show its effects on PAVM formation. Anti COX-2 therapy could also be tested in human individuals, particularly in patients presenting a hepatopulmonary syndrome or HHT with small PAVM.

IMPLICATION OF THE HYPOTHESIS

PAVMs are one of the main causes of morbidity in patients presenting with HHT disease, owing to the risks of rupture as well as paradoxical embolism exposing to stroke and/or cerebral abscess. Percutaneous embolization has become the treatment of choice of PAVM. Anti COX2 may prevent from PAVM development and subsequent related complications and avoid either surgery and/or percutaneous embolization and thus subsequent related complication.

Standard anticoagulation for mesenteric vein thrombosis, revealing a 'zebra' diagnosis: hereditary haemorrhagic telangiectasia--the dripping truth!

A 60-year-old man was treated in the hospital for mesenteric vein thrombosis and discharged home on anticoagulation. On warfarin the patient started to bleed profusely from the nose and tongue. He was evaluated by ENT (ears, nose and throat); a nasal endoscopy revealed several vascular ectasias. Subsequent detailed history and general physical examination established the diagnosis of hereditary haemorrhagic telangiectasia also known as Osler-Weber-Rendu syndrome. On further evaluation, pulmonary arteriovenous malformations were diagnosed on imaging and treated by intervention radiology. In hindsight, the diagnosis could have been made in the general practitioner's office with just a routine thorough history and a physical examination at a new patient visit. We report this case to stress upon the importance of vigilant clinical, medical and family history and a thorough examination to establish an early diagnosis of this not-so-rare entity.

Diagnosis and treatment of pulmonary arteriovenous malformations in hereditary hemorrhagic telangiectasia: An overview

Hereditary hemorrhagic telangiectasia (HHT) or Rendu-Osler-Weber disease is an autosomic dominant disorder, which is characterized by the development of multiple arteriovenous malformations in either the skin, mucous membranes, and/or visceral organs. Pulmonary arteriovenous malformations (PAVMs) may either rupture, and lead to life-threatening hemoptysis/hemothorax or be responsible for a right-to-left shunting leading to paradoxical embolism, causing stroke or cerebral abscess. PAVMs patients should systematically be screened as the spontaneous complication rate is high, by reaching almost 50%. Neurological complications rate is considerably higher in patients presenting with diffuse pulmonary involvement. PAVM diagnosis is mainly based upon transthoracic contrast echocardiography and CT scanner examination. The latter also allows the planification of treatments to adopt, which consists of percutaneous embolization, having replaced surgery in most of the cases. The anchor technique consists of percutaneous coil embolization of the afferent pulmonary arteries of the PAVM, by firstly placing a coil into a small afferent arterial branch closely upstream the PAVM. Enhanced contrast CT scanner is the key follow-up examination that depicts the PAVM enlargement, indicating the various mechanisms of PAVM reperfusion. When performed by experienced operators as the prime treatment, percutaneous embolization of PAVMs, is a safe, efficient and sustained therapy in the great majority of HHT patients.

Bilateral lung transplant for hereditary hemorrhagic telangiectasia in a pediatric patient

HHT is an autosomal dominant vascular dysplasia, in which abnormalities of endothelial cells cause patients to develop mucocutaneous telangiectasias, and AVMs of the pulmonary, hepatic, and cerebral circulations. Pulmonary AVMs occur in more than 20% of patients with HHT, and presentation varies from simple diffuse telangiectasias to large complex structures. Surgical management is usually indicated for large pulmonary AVMs. Treatment options for pulmonary AVMs include therapeutic embolization, segmental or lobar resection of the affected lung, and less commonly lung transplantation. Here we report the first successful case of a bilateral lung transplant for a four-yr-old girl with HHT.

Transcatheter Embolization of Giant Pulmonary Arteriovenous Malformation with an Amplatzer Vascular Plug II

Pulmonary arteriovenous malformation (PAVM) is a rare anomalous direct communication between the pulmonary artery and vein with a considerable risk of serious complications such as cerebral thromboembolism or abscess and pulmonary hemorrhage. Although the past, surgical resection such as lobectomy was mostly used to treat PAVM, the recent development of endovascular treatment has made it a primary consideration to perform transcatheter embolization using coils or detachable balloons. We report a case of successful transcatheter embolization of giant PAVM with the second generation Amplatzer vascular plug II as a new self-expanding device.

Embolisation for pulmonary arteriovenous malformation

BACKGROUND

Pulmonary arteriovenous malformations are abnormal direct connections between the pulmonary artery and pulmonary vein which result in a right-to-left shunt. They are associated with substantial morbidity and mortality mainly from the effects of paradoxical emboli. Potential complications include stroke, cerebral abscess, pulmonary haemorrhage and hypoxaemia. Embolisation is an endovascular intervention based on the occlusion of the feeding arteries the pulmonary arteriovenous malformations thus eliminating the abnormal right-to-left-shunting.

OBJECTIVES

To determine the efficacy and safety of embolisation in patients with pulmonary arteriovenous malformations including a comparison with surgical resection and different embolisation devices.

SEARCH METHODS

We searched the Cystic Fibrosis and Genetic Disorders Group's Trials Register; date of last search: 09 February 2012.We also searched the following databases: the Australian New Zealand Clinical Trials Registry; ClinicalTrials.gov; International Standard Randomised Controlled Trial Number Register; International Clinical Trials Registry Platform Search Portal (last searched 15 May 2012).We checked cross-references and searched references from review articles.

SELECTION CRITERIA

Trials in which individuals with pulmonary arteriovenous malformations were randomly allocated to embolisation compared to no treatment, surgical resection or embolisation using a different embolisation device.

DATA COLLECTION AND ANALYSIS

Studies identified for potential inclusion were independently assessed for eligibility by two authors, with excluded studies further checked by a third author. No trials were identified for inclusion in the review and hence no analysis was performed.

MAIN RESULTS

There were no randomised controlled trials identified.

AUTHORS' CONCLUSIONS

There is no evidence from randomised controlled trials for embolisation of pulmonary arteriovenous malformations. However, randomised controlled trials are not always feasible on ethical grounds. Accumulated data from observational studies suggest that embolisation reduces morbidity. A standardised approach to reporting with long-term follow-up through registry studies can help to strengthen the evidence for embolisation in the absence of randomised controlled trials.

Intrapleural rupture of a pulmonary arteriovenous fistula

A 72-year-old white woman was admitted to the hospital for mitral valve replacement with a metallic valve. A few days after surgery, the patient experienced a sudden cardiac arrest and died because of the intrapleural rupture of a pulmonary arteriovenous fistula.

Contralateral decubitus positioning enhances computed tomographic angiographic evaluation of pulmonary vasculature in a patient with a pulmonary arteriovenous malformation

Computed tomographic pulmonary angiography has become the diagnostic procedure of choice in patients suspected of having a pulmonary embolus. However, intrapulmonary shunting of blood in a variety of pathologic conditions can cause suboptimal opacification of the pulmonary arterial circulation and result in a suboptimal or even nondiagnostic study. Radiologists should be aware of these conditions and be familiar with positioning techniques to minimize such shunting. We report a patient suspected of having pulmonary embolism, in whom a preexisting unilateral arteriovenous malformation prevented adequate evaluation of the pulmonary circulation. Positioning the patient in the contralateral decubitus position significantly enhanced image quality.

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.