Embolotherapy of pulmonary arteriovenous malformations with detachable balloons: long-term durability and efficacy

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.

Endovascular Embolisation of Pulmonary Arteriovenous Malformation Using Amplatzer Vascular Plugs

Pulmonary arteriovenous malformation (PAVMs) are abnormal communications between pulmonary arteries and veins. The rarity of their occurrence, coupled with the risks they pose, including brain abscess, embolic stroke, and myocardial infarction, mandates that they should not be overlooked in the differential diagnosis of patients presenting with haemoptysis, dyspnea, clubbing, cyanosis, hypoxemia, or epistaxis.

We present the case of a 41-year-old local female who presented to our hospital as an outpatient with decreased oxygen saturation (SpO₂) of 70%-80% for the past two years with a final diagnosis of PAVM. The initial baseline workup showed polycythemia with a hemoglobin level of 19 mg/dL and raised hematocrit. She had extensive workup in the past two years for her polycythemia including gene mutation testing and cardiac workup which all turned out normal. Her chest X-ray (CXR) showed right lung opacity which was initially considered to be infective but it did not respond to antibiotic treatment. Later on, a CT scan of the chest was performed and findings were typical of a large PAVM which had two feeding arteries. The patient was referred to a cardiothoracic surgeon who sent the patient to the interventional radiology section for endovascular management.

The embolization procedure was then performed and both feeders were successfully embolised. After the procedure, the patient's SpO₂ levels were restored to 95%-96%, and no post-procedure complications were noted.

Imaging to intervention: a review of what the Interventionalist needs to Know about Hereditary Hemorrhagic Telangiectasia

Hereditary hemorrhagic telangiectasia (HHT) is a disorder that affects 1 in 5000-10,000 people worldwide and can result in devastating complications such as cerebral abscess, stroke, massive hemorrhage, and even death. HHT is an autosomal dominant disorder that leads to the formation of abnormal communication between the arteries and veins with a resultant spectrum of vascular anomalies. The disorder affects many organ systems and thus requires a dedicated multidisciplinary approach. Interventional radiologists are vital members of this team providing expertise not only in disease management, but in complex embolotherapy, helping to maintain the health of these patients. This article reviews clinical manifestations, screening guidelines, diagnostic criteria, and endovascular management of HHT.

Clinical Analysis of Transcatheter Embolotherapy for Congenital Pulmonary Arteriovenous Fistulas in Children

Objective: To summarize the clinical features and therapeutic effects of transcatheter embolotherapy for congenital pulmonary arteriovenous fistulas (PAVFs) in children, and to explore the method and therapeutic principle of transcatheter embolotherapy for congenital PAVFs in children.Method: We retrospectively reviewed nine patients with PAVF who underwent transcatheter embolotherapy in the Children’s Hospital of Chongqing Medical University from July 2004 to July 2019, including the demographic characteristics, clinical manifestations, efficiency of closure, and follow-up.Results: Transcatheter embolotherapy was successful in all cases, and the symptom remission rate was 100% during the follow-up. No residual shunts or other complications occurred during the follow-up period. Compared with before embolotherapy, there were significant changes in the percentage of saturated oxyhemoglobin and total hemoglobin level at the last follow-up (t=10.06, P=0.000; t=3.055, P=0.0076). No significant difference was observed in pulmonary artery pressure before and after embolotherapy (t=0.13, P=0.90).Conclusions: Transcatheter embolotherapy offers the advantages of safety, with a decreased risk of trauma and a specific effect of treatment, and therefore is recommended as the first-line treatment for congenital PAVFs in children. However, continued research is necessary to understand the full potential of transcatheter embolotherapy.

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.

Orthodeoxia without Platypnea in Hereditary Hemorrhagic Telangiectasia in the Presence of a Cerebral Abscess and Multiple Pulmonary Arteriovenous Malformations: Unusual Complications and Transcatheter Endovascular Treatment

Hereditary hemorrhagic telangiectasia is a rare autosomal-dominant condition affecting visceral blood vessel development. Cerebral and most commonly pulmonary arteriovenous malformations are found in the majority of symptomatic patients. The most common complications include embolic strokes and cerebral abscesses, which have been attributed to abnormal vessel communications. Platypnea orthodeoxia is a rare condition that presents dyspnea and oxygen desaturation when adopting an upright position and is relieved on decubitus. The association between hereditary hemorrhagic telangiectasia, pulmonary arteriovenous malformations, and platypnea orthodeoxia has been described in medical literature; however, orthodeoxia as a single entity without platypnea has not been described yet, especially associated with complications of this hereditary condition. We present the case of a 38-year-old male with persistent headaches, in whom a cerebral lesion was detected. Orthostatic tachycardia and severe orthodeoxia without platypnea were evidenced during physical examination. The patient was subsequently diagnosed with hereditary hemorrhagic telangiectasia and underwent cerebral abscess drainage as well as transcatheter endovascular closure of multiple pulmonary arteriovenous malformations. For this reason, the concept of platypnea orthodeoxia syndrome needs further revision. Patients presenting refractory hypoxemia should warn physicians to initially evaluate their oxygen saturation measurements during standing and decubitus position, even though platypnea may not be present.

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

Pulmonary arteriovenous malformations (PAVMs) are abnormal vascular structures that most often connect a pulmonary artery to a pulmonary vein, bypassing the normal pulmonary capillary bed and resulting in an intrapulmonary right-to-left shunt. As a consequence, patients with PAVM can have hypoxemia and paradoxical embolization complications, including stroke and brain abscess. PAVMs may be single or multiple, unilateral or bilateral, and simple or complex. Most PAVMs are hereditary and occur in hereditary hemorrhagic telangiectasia, an autosomal dominant vascular disorder, and screening for PAVM is indicated in this subgroup. PAVMs may also be idiopathic, occur as a result of trauma and infection, or be secondary to hepatopulmonary syndrome and bidirectional cavopulmonary shunting. Diagnostic testing involves identifying an intrapulmonary shunt, with the most sensitive test being transthoracic contrast echocardiography. Chest CT scan is useful in characterizing PAVM in patients with positive intrapulmonary shunting. Transcatheter embolotherapy is the treatment of choice for PAVM. Lifelong follow-up is important because recanalization and collateralization may occur after embolization therapy. Surgical resection is rarely necessary and reserved for patients who are not candidates for embolization. Antibiotic prophylaxis for procedures with a risk of bacteremia (eg, dental procedures) is recommended in all patients with PAVM because of the risk of cerebral abscess.

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.

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.

Transseptal guidewire stabilization for device closure of a large pulmonary arteriovenous malformation

A 46-year-old man presenting with massive hemoptysis was found to have a large pulmonary arteriovenous malformation (PAVM) in the right lung. Closure of the PAVM with an Amplatzer-type duct occluder was hampered by inability to advance the device delivery sheath into the PAVM due to vessel tortuosity and inadequate guidewire support. Atrial septal puncture was performed and a femorofemoral arteriovenous guidewire loop through the right pulmonary artery, PAVM, and left atrium was created. Traction on both ends of the guidewire loop allowed advancement of the device delivery sheath into the PAVM and successful completion of the procedure. Transseptal guidewire stabilization can be a valuable option during device closure of large PAVMs when advancement, stability, or kinking of the device delivery sheath is an issue.

A friend to the airways: a review of the emerging clinical importance of the bronchial arterial circulation

Lungs receive the bulk of their blood supply through the pulmonary arteries. The bronchial arteries, on the other hand, vascularize the bronchi and their surroundings. These two arteries anastomose near the alveolar ducts. Contrary to the pulmonary circulation which is fairly well studied, the bronchial arteries have been appreciated more by their absence, and in some cases, by an interruption in the pulmonary arterial flow. Therefore, a more accurate anatomical and functional knowledge of these atherosclerosis-resistant vessels is needed to help surgeons and clinicians to avoid iatrogenic injuries during pulmonary interventions. In this review, we have revisited the anatomy and pathophysiology of the bronchial arteries in humans, considering the recent advances in imaging techniques. We have also elaborated on the known clinical applications of these arteries in both the pathogenesis and management of common pulmonary conditions.

Complications of embolization

Embolization is a remarkably versatile procedure used in nearly all vascular and nonvascular systems to treat a wide range of pathology. The published literature is rich with studies demonstrating the enormous therapeutic potential offered by embolization procedures, and the possibilities continue to expand with the advent of new embolization agents and techniques. Unfortunately, with this variety and innovation comes a wide spectrum of potential complications, not always easy to classify and summarize, associated with embolization. This article reviews the procedures and associated complications of arterial and venous embolization procedures, organized by vascular distribution.

Embolisation therapy for pulmonary arteriovenous malformations

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 therapy is a form of treatment based on the occlusion of the feeding arteries to a pulmonary arteriovenous malformation and can prevent many of these debilitating and life-threatening complications.

OBJECTIVES

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

SEARCH STRATEGY

We searched the Cystic Fibrosis and Genetic Disorders Group's Trials Registers (last searched 07 September 2009). 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 22 November 2009). We checked cross-references and searched references from review articles. Finally, we contacted manufacturers and specialised centres for unpublished and ongoing trials.

SELECTION CRITERIA

Trials in which individuals with pulmonary arteriovenous malformations were randomly allocated to embolisation therapy compared to no treatment, surgical resection or a different embolisation device. Studies identified for potential inclusion were independently assessed for eligibility by two authors, with excluded studies further checked by a third author.

DATA COLLECTION AND ANALYSIS

No trials were identified. As this was the case, no analysis was performed.

MAIN RESULTS

There were no randomised controlled trials identified.

AUTHORS' CONCLUSIONS

Currently there are no randomised controlled trials to support or refute embolisation therapy for treatment of pulmonary arteriovenous malformations. However, randomised controlled trials are not always feasible on ethical grounds. Observational studies suggest that embolisation therapy reduces mortality and morbidity compared to no treatment in patients. A standardised approach to reporting with long-term follow up through registry studies can help to strengthen the evidence base for embolisation therapy in the absence of randomised controlled trials. Future viable randomised controlled trials may compare different embolisation devices against each other.

[Embolotherapy of pulmonary arteriovenous malformations: long-term clinical and radiological follow-up]

Pulmonary arteriovenous malformations (PAVM) are abnormal communications between the pulmonary arteries and pulmonary veins. The large majority are congenital and are commonly associated with Rendu-Osler-Weber disease or hereditary haemorrhagic telangiectasia. The PAVM may remain asymptomatic or manifest with hypoxemia, hemoptysis, hemothorax and/or neurologic symptoms. Despite its low incidence, the PAVM represent a serious entity that must be taken into account since untreated patients are in risk and present a poor prognosis. Transcatheter embolization with coils or detachable balloons is currently accepted as the treatment of choice. We present 6 patients (5 women and one man) who underwent embolotherapy of PAVM showing the long-term clinical and radiological follow-up.

Bronchial arteriovenous malformation with large aneurysm, resected by video-assisted thoracic surgery

Bronchial arteriovenous malformation with a large aneurysm appearing as a mass shadow in the right hilum on chest imaging was successfully extirpated thoracoscopically without any lung resection. Preoperative angiography showed tortuous, enlarged right bronchial arteries with an aneurysm connecting to the pulmonary artery, which could not be totally embolized via the transcatheter approach because of the length of the abnormal bronchial artery and possibility of embolotherapy-induced pulmonary infarction. Histological examination revealed defects of the media and internal elastic lamina of the resected bronchial arteries and aneurysm. The patient was free of hemoptysis and other airway symptoms 4 years after surgery.

Pulmonary arteriovenous malformations: how do I embolize?

Pulmonary arteriovenous malformations (PAVM) are high-flow, low-pressure shunts, consisting of a single feeding artery connecting via an aneurysmal sac to a draining vein. The aneurysmal connection is referred to as an aneurysmal sac. The "filter capacity" of the pulmonary capillaries is lost and results in predisposition to brain abscess, stroke, and transient ischemic attack and, when multiple, dyspnea, because of right-to-left shunting and hypoxemia. PAVM are markers of hereditary hemorrhagic telangiectasia (HHT). Up to 30% of patients with HHT have PAVM complicating their disorder. Left untreated, 50% of patients with PAVM will develop disabling or fatal complications. In addition to stroke and transient ischemic attack syndromes due to passage of paradoxical emboli through the PAVM, rupture of the aneurysmal sac, particularly in the third trimester of pregnancy, can lead to fatal hemoptysis or hemothorax. Finally, brain abscess or more obscure musculoskeletal or spinal infections may be secondary to PAVM. Since detachable silicone balloons are no longer available, we have developed precise techniques for closing pulmonary malformations using pushable fibered coils. It is not the coil that is so important, but it is the use of coaxial or triaxial catheters that allow for precise placement of the coil. Cross-sectional occlusion is essential for embolization of PAVM and this is achieved using the "anchor" or "scaffold" technique. Our recent results indicate permanent involution of treated malformations with a 3% recurrence rate. All patients should be assessed for other manifestations of HHT before treatment and they are best followed in one of the 20 HHT Centers worldwide (www.hht.org).

Long-term follow-up after embolization of pulmonary arteriovenous malformations with detachable silicone balloons

Long-term follow-up results after embolization of 13 pulmonary arteriovenous malformations in 10 patients by use of 14 detachable silicone balloons are given. Patients were followed for a mean of 99 months (range, 63-123 months) with chest x-rays and for a mean of 62 months (range, 3-101 months) with pulmonary angiography. Fifty-four percent of the balloons were deflated at latest radiographic chest film follow-up, but at pulmonary angiographic follow-up all embolized malformations were without flow irrespective of whether or not the balloons were visible. Detachable silicone balloons are not available anymore, but use of these balloons for embolization of pulmonary arteriovenous malformations has been shown to be a safe and precise method, with immediate occlusion of the feeding artery and with long-lasting occlusion, even though many balloons deflate with time, leaving a fibrotic scar replacing the pulmonary arteriovenous malformation. No case of recanalization has been discovered, and these results seem to justify a reduced number of controls of these balloon-embolized malformations.

Transcatheter closure of pulmonary arteriovenous malformations with amplatzer devices

OBJECTIVE

To review the authors' experience with transcatheter closure of pulmonary arteriovenous malformations (PAVMs) using amplatzer duct occluder (ADO) devices and vascular plugs (AGA Medical, Golden Valley, MN) and present a novel technique for delivery sheath placement and device delivery.

BACKGROUND

PAVMs can cause cyanosis, fatigue, polycythemia, and thromboembolic phenomena. Transcatheter closure using coils, detachable balloons, and various devices has replaced surgery as the preferred therapy.

METHODS

Between January 2001 and December 2004, five patients (2M, 3F) of median age 33 years (14-49) were referred for transcatheter closure of multiple PAVMs. All patients were diagnosed previously with hereditary hemorrhagic telangectasia. The procedures were performed with sedation using a percutaneous transcatheter technique via the femoral vein under fluoroscopic guidance.

RESULTS

A total of 14 PAVMs (11 ADO and 3 plugs) were closed in five patients. Three patients required two procedures after developing additional PAVMs. All attempts at PAVM closure were successful. Oxygen saturation increased from 88.4 +/- 6.1 to 96.4 +/- 0.5 (P < 0.05). No complications, including air or thromboembolism, hemoptysis, or chest pain, occurred. At median follow-up of 3.4 years (1.4-3.6), all patients are alive and have suffered no embolic phenomena or infection.

CONCLUSION

Amplatzer patent ductus arteriosus occluders and vascular plugs are safe and effective in the closure of PAVMs in the acute setting and at intermediate follow-up. Placement of a long delivery sheath can be facilitated by the methods outlined. Though promising, further clinical evaluation of these devices is required. Their apparent advantages must be compared to other techniques and devices for transcatheter PAVM closure.

A New Device for Vascular Embolization: Report on Case of Two Pulmonary Arteriovenous Fistulas Embolization Using the Amplatzer Vascular Plug

A pulmonary arteriovenous fistula (PAVF) is a rare vascular malformation commonly treated by embolization with coils or balloons to prevent the risk of several serious complications such as cerebral embolism and brain abscess. A 32-year-old female with two PAVFs and neurological ischemic manifestations has been successfully treated by transcatheter embolization of both fistulas using a new device (Amplatzer Vascular Plug). This self-expanding cylindrical nitinol mesh cage with high radial strength allows a chance of relocation until properly positioned. It is preferred to coils or balloons because a large caliber of feeding artery implied high risk of uncontrollable distal embolization. There appear to be no reports in the literature concerning use of this device, which could represent a useful innovative tool in embolotherapies, especially in large vascular areas.

Endovascular Therapy of Pulmonary Arteriovenous Malformations

The utility of computed tomography pulmonary angiography (CTPA) for coil embolization therapy of pulmonary arteriovenous malformations (PAVMs) was considered. Three consecutive patients (group A) with PAVMs underwent CTPA and coil embolization. The CTPA was performed using a 16-detector-row computed tomography scanner. After careful selection of pulmonary vessel trees, each feeding artery, nidus, and drainage vein was colored using different codes. By using the colored images, a 5-French catheter was shaped to fit to each feeding artery, the best fluoroscopic angle to select each feeding artery was chosen, and interlocking detachable coils (IDCs) were used in embolization. The procedure time and contrast material dose of group A were compared with those of the previous 3 patients (group B) who were treated by the conventional method. All PAVMs of both groups were completely embolized without coil migration. The average procedure time per lesion was 48.4 minutes for group A and 124.0 minutes for group B (P < 0.05). The average contrast material dose per lesion was 37.5 mL in group A and 76.0 mL in group B (P < 0.05). Using CTPA and IDCs, procedure time and contrast material dose were statistically significantly reduced. This combination therapy is useful in treating PAVMs less invasively.

Clinical and Anatomic Outcomes after Embolotherapy of Pulmonary Arteriovenous Malformations

PURPOSE

To assess long-term clinical and imaging results of technically successful pulmonary arteriovenous malformation (AVM) embolization.

MATERIALS AND METHODS

One hundred fifty-five patients with pulmonary AVMs underwent embolization during a period of 3 years. Recommended follow-up included clinical assessment, helical computed tomography, and physiologic evaluation within 1 year and then every 5 years.

RESULTS

Hereditary hemorrhagic telangiectasia was present in 148 patients (95%). Four hundred fifteen pulmonary AVMs were occluded during 205 procedures. Clinical follow-up was available in all patients over 3-7 years and imaging follow-up was available in 144 patients (393 lesions) over 1-7 years (mean, 2.9 y). Problems related to pulmonary AVMs occurred in 35 patients (23%) at 42 time points: 22 patients with 23 symptomatic events and 17 patients with 19 asymptomatic events. Symptoms resulted from growth of nonembolized pulmonary AVMs (n = 19), residual embolized pulmonary AVMs (n = 5), or both (n = 2). Symptoms consisted of respiratory manifestations (n = 13), cerebral ischemia (n = 4), brain abscess (n = 5), hemoptysis (n = 3), and seizure (n = 1). Imaging showed pulmonary AVM involution in 97% of embolized lesions and 11 residual lesions (2.8%) in 10 patients (6.9%). These were caused by recanalization (n = 7), presence of an accessory feeding artery (n = 1), pulmonary collateral vessels (n = 1), and bronchial collateral vessels (n = 2). CT detected 10 of the 11 residual lesions. Imaging detected 97 previously small pulmonary AVMs that had enlarged to a significant size in 28 patients (18%), 15 of whom were symptomatic and 13 of whom were asymptomatic.

CONCLUSIONS

Clinical and anatomic evaluation after pulmonary AVM embolization is important to detect persistent or reperfused lesions and enlarging lesions, with the latter more common. Patients with persistent, reperfused, or enlarging lesions often have symptoms, but a significant minority of patients are asymptomatic. More frequent assessment may improve detection before the onset of symptoms.

Reperfusion of Pulmonary Arteriovenous Malformations after Embolotherapy

PURPOSE

To describe the mechanisms and risk factors associated with reperfusion of successfully treated pulmonary arteriovenous malformations (PAVMs) after embolotherapy.

MATERIALS AND METHODS

Among 112 consecutive patients with PAVMs treated by embolotherapy, 19 patients were identified who had 33 angiographically confirmed reperfused PAVMs. A retrospective analysis of computed tomography (CT) and angiography was performed in patients with documented reperfused PAVMs in which reperfused PAVMs were compared with nonreperfused PAVMs. CT images were examined for persistence of the aneurysm and/or draining vein after initial embolotherapy and correlated with angiography to determine the mechanism of reperfusion. PAVM and embolic agent characteristics (eg, feeding artery size and number; PAVM location; coil size, number, and location) were evaluated for association with reperfusion. The outcomes of repeat embolotherapy for reperfused PAVMs were evaluated.

RESULTS

The PAVM aneurysm and/or draining vein persisted on CT after initial embolotherapy in all reperfused PAVMs and resolved in all nonreperfused PAVMs (in patients with nondiffuse PAVMs). Recanalization was the mechanism of reperfusion in 88%. Reperfusion was associated with the use of a single coil (P < .0001), oversized coils (P < .0001), coil placement more than 1 cm from the aneurysm (P < .0001), and increased feeding artery size (P < .001). Repeat embolotherapy for reperfused PAVMs was technically successful in 94% of cases. In the remaining 6% of cases, insufficient feeding artery length prevented safe repeat treatment. After a mean follow-up of 41 months, 42% of reperfused PAVMs in our series have been successfully treated again and occluded.

CONCLUSIONS

Recanalization is the most common mechanism of PAVM reperfusion. Increased feeding artery diameter, low number of coils, use of oversized coils, and proximal coil placement within the feeding artery are associated with reperfusion. Distal coil placement facilitates repeat embolization if reperfusion occurs.

Pulmonary arteriovenous malformations in children: outcomes of transcatheter embolotherapy

OBJECTIVE

To describe outcomes of transcatheter embolotherapy (TCE) in children with pulmonary arteriovenous malformations (PAVMs).

STUDY DESIGN

Chart and imaging review of all children (age </=18 years) treated for PAVMs by TCE at three hereditary hemorrhagic telangiectasia centers.

RESULTS

All 42 treated patients were included, with a mean age of 12 years (range, 4 to 18). Cyanosis was present in 25 of 42 patients (60%). Hemoptysis had occurred in 3 of 42 patients (7%) and neurologic complications (stroke, cerebral abscess) occurred in 8 patients (19%) before assessment. PAVMs were focal in 30 of 42 (71%) and diffuse in 12 of 42 (29%) patients. TCE was performed for 172 PAVMs and 35 diffuse regions (regional TCE). Follow-up was obtained in 38 of 42 (90%) patients (mean, 7 years). After TCE in patients with focal PAVMs, oxygenation improved significantly, with no further complications from the PAVMs. Reperfusion was noted in 23 of 153 (15%) PAVMs. Eighteen of 23 (78 %) of these were retreated, with documented aneurysmal involution in 10 of 13 (77%) patients. TCE complications included pleuritic chest pain (24% of sessions) and deployment complications (device paradoxical embolization or device misplacement) (3% of sessions, 1% of PAVMs), with no long-term complications.

CONCLUSIONS

PAVMs cause life-threatening complications in children; treatment with TCE is safe, with complication rates comparable to adult rates.

Reperfusion of Complex Pulmonary Arteriovenous Malformations After Embolization: Report of Three Cases

The purpose of this report is to discuss the different mechanisms of reperfusion of pulmonary arteriovenous malformations (PAVMs) after embolization. Transcatheter embolotherapy is currently the first-line treatment of PAVMs to prevent neurologic complications or pulmonary hemorrhage. Initial good results can be expected but we report three cases of reperfusion of complex large PAVMs after coil embolization. After adequate embolization, reperfusion of PAVMs may occur by several mechanisms including recanalization of embolized arteries, recruitment of normal arterial branches, growth or enlargement and development of a systemic arterial supply.

Use of the TriSpan Coil to Facilitate the Transcatheter Occlusion of Pulmonary Arteriovenous Malformation

Pulmonary arteriovenous malformation (PAVM) is a rare vascular malformation of the lung which may occur as an isolated entity or in association with hereditary hemorrhagic telangiectasia (HHT). Because of considerable risk of serious complications such as cerebral embolism, brain abscess and pulmonary hemorrhage, definitive treatment should be considered in most patients. Embolization with coils or detachable balloons is currently the preferred treatment. Paradoxical embolization of coils and balloons may happen, especially in patients with PAVMs with large feeding arteries. In this report we present our initial experience with the use of the TriSpan coil to lower the risk of coil migration during the transcatheter occlusion of PAVMs.

Embolotherapy of Pulmonary Arteriovenous Malformations: Long-term Results in 112 Patients

PURPOSE

To evaluate the long-term results of embolotherapy of pulmonary arteriovenous malformations (PAVMs) in a large group of patients.

MATERIALS AND METHODS

Between July 1988 and August 2001, 134 consecutive patients underwent embolotherapy of PAVMs with feeding arteries larger than 3 mm or that had previously caused bleeding or systemic complications. The mean follow-up was 62.2 months. The primary endpoints of the study were the efficacy of embolotherapy, decrease in right-to-left shunt, and increase in partial arterial oxygen pressure (PaO(2)); the secondary endpoint was the prevalence of complications. Standard follow-up consisted of yearly history, chest radiography, and arterial blood gas measurement.

RESULTS

Follow-up was available in 112 patients. Initially, 296 PAVMs were embolized in these patients. Nineteen patients (17%) underwent a second procedure and four patients underwent a third procedure because of recanalization of originally occluded feeding arteries (25 PAVMs, 8%) or interval enlargement of untreated PAVMs (53 PAVMs). In total, 349 PAVMs were embolized in 157 sessions. The mean diameter of occluded vessels was 4.7 mm. The long-term outcomes of embolotherapy were successful in 83% of patients overall and in 96% of patients in whom all angiographically visible PAVMs were embolized. Recanalization occurred in 12 of 16 patients who underwent repeat treatment because of enlargement of nonembolized PAVMs. Postprocedural pleurisy occurred after 14 of 157 sessions (9%). Periprocedural complications occurred in 12 sessions (8%) and included migration of an embolic device, transient ischemic attack (TIA), angina pectoris, and early cerebral infarction after embolization. Three patients experienced TIA and two patients experienced a cerebral abscess during follow-up after embolotherapy.

CONCLUSIONS

Embolotherapy of PAVMs is efficacious and durable in the majority of patients. Patients should remain under regular review because recanalization of PAVMs or enlargement of untreated PAVMs can occur years after treatment.

Embolotherapy of Pulmonary Arteriovenous Malformations: Efficacy of Platinum versus Stainless Steel Coils

PURPOSE

To compare the results of embolotherapy of pulmonary arteriovenous malformations (PAVMs) with use of platinum versus stainless-steel coils.

MATERIALS AND METHODS

From a database of 78 consecutive patients with PAVMs treated by embolotherapy between May 1992 and September 2001, 54 patients with 306 PAVMs were selected for retrospective evaluation. Exclusion criteria were PAVMs with less than 12 months of follow-up computed tomography (CT) of the thorax (n = 15), embolotherapy with a mixture of embolic materials (n = 8), and repeat embolotherapy for previous treatment failures (n = 1). Successful treatment was defined as complete resolution of the aneurysm sac and draining vein on follow-up CT (all patients) and/or absence of contrast material flow through the PAVM on pulmonary angiography (n = 27).

RESULTS

Of 267 PAVMs embolized with stainless-steel coils, 249 (93.3%) were successfully occluded (mean follow-up, 3.1 years). Of 39 PAVMs embolized with platinum coils, 35 (89.7%) were successfully occluded (mean follow-up, 2.1 years). There was no significant difference in success between the two groups (P =.5). The mean feeding artery size was significantly larger (P <.0001) in the platinum group (4.3 mm) than in the stainless-steel group (3.5 mm). Potentially serious complications included coil reflux (n = 3), PAVM perforation (n = 2), self-limited neurologic deficit (n = 2), and systemic embolization of a coil (n = 1) in the stainless-steel group, and PAVM perforation (n = 2) in the platinum group. There were no long-term sequelae.

CONCLUSIONS

Coil embolotherapy is highly efficacious, with no statistically significant difference between platinum and stainless-steel coils. The slightly higher proportion of sustained occlusion with stainless-steel coils may be partly explained by the larger mean feeding artery size in the platinum group. The study is limited by the small sample size of the platinum group.

Techniques and applications of transcatheter embolization procedures in pediatric cardiology

Transcatheter embolization of congenital or acquired superfluous vascular structure has become routine procedures performed by interventional pediatric cardiologists. Embolization procedure is often part of a collaborative effort with cardiac surgeons to palliate complex congenital heart defect, such as in embolizing aortopulmonary collateral arteries in patient with single ventricle physiology. In other cases, the procedure is the definitive treatment as in embolizing coronary artery fistula. Pediatric cardiologists performing embolization procedures should be familiar with available technologies as well as understand the underlying cardiac anatomy and pathophysiology. This article provides a comprehensive review of presently available embolization agents and technologies. Some of the technologies are used only by interventional radiologists but may be useful to pediatric cardiologists. Specific clinical applications in pediatric cardiology are also discussed with summary of current literature. With continue advancement in transcatheter technology and operator expertise, all unwanted vascular communication should be amenable to transcatheter embolization.

Interventional Occlusion of a Large Pulmonary Arteriovenous Malformation with an Amplatzer Septal Occluder

Interventional occlusion of pulmonary arteriovenous malformations with large feeding arteries may be associated with an increased risk of device embolization. In a 40-year-old patient with a solitary pulmonary arteriovenous malformation one large feeding artery was successfully closed by means of an Amplatzer septal occluder and detachable coils. The use of an Amplatzer septal occluder should be considered as an alternative therapeutic option in cases of huge pulmonary arteriovenous malformation to reduce the risk of device embolization.

Vein of Galen technique for occluding the aneurysmal sac of pulmonary arteriovenous malformations

In seven of 255 consecutive patients (2.7%) who underwent pulmonary arteriovenous malformation (PAVM) embolization at our center between July 1, 1996, and July 1, 2000, the feeding artery was considered too short for safe occlusion with use of standard stainless-steel coils or detachable balloons. These patients were successfully treated with use of a modified vein of Galen technique similar to the one used for managing intracranial vein of Galen aneurysms. In this article, the authors report their experience with this technique in safely occluding the aneurysmal sacs of PAVMs in patients with short (<2 cm) feeding pulmonary arteries.

Pulmonary arteriovenous malformations: effect of embolization on right-to-left shunt, hypoxemia, and exercise tolerance in 66 patients

OBJECTIVE

This study assessed the effect and safety of percutaneous transcatheter coil embolization of pulmonary arteriovenous malformations.

MATERIALS AND METHODS

In 58 (88%) of 66 patients, all malformations with feeding vessels greater than or equal to 3 mm in diameter were embolized with steel coils. Arterial oxygen saturation at rest and exercise, intrapulmonary right-to-left anatomic shunt fraction ((99m)Tc-macroaggregate injection), maximum exercise capacity (incremental work rate test), and pulmonary function were measured before and after embolization. Complications were analyzed.

RESULTS

Three categories of patients were identified. Patients in group 1 (27%) had complete occlusion of all angiographically visible pulmonary arteriovenous malformations; patients in group 2 (61%) had complete occlusion of all malformations with feeding vessels greater than or equal to 3 mm in diameter, but with smaller lesions persisting; and patients in group 3 (12%) had incomplete embolization, with feeding vessels greater than or equal to 3 mm in diameter remaining. The mean right-to-left shunt after embolization was least in group 1 (7%), intermediate in group 2 (10%), and greatest in group 3 (19%). Arterial oxygen saturation and right-to-left shunt fraction returned to normal levels (>96% and <3.5%, respectively) in 33% of patients. A significant improvement occurred after embolization in carbon monoxide diffusing capacity per unit of alveolar volume and in exercise capacity in 16 and 10 patients, respectively. In 93 procedures, 12 complications (13%) occurred.

CONCLUSION

Coil embolization of pulmonary arteriovenous malformations is effective in reducing right-to-left anatomic shunt fraction and in improving arterial oxygenation. Coil embolization of pulmonary arteriovenous malformations is well tolerated and has a low complication rate.

Pulmonary arteriovenous malformations: embolotherapy with superselective coaxial catheter placement and filling of venous sac with Guglielmi detachable coils

PURPOSE

To assess the value of superselective embolotherapy of pulmonary arteriovenous malformations (PAVMs) with coaxial microcatheters and 0.018-inch microcoils and to evaluate the technique of filling the venous sac with Guglielmi detachable coils (GDCs).

MATERIALS AND METHODS

Six consecutive patients (three men, three women; mean age, 46 years, age range, 18-74 years) underwent arterial embolization of nine PAVMs with superselective catheterization with a 3-F coaxial catheter system and embolization with 0.018-inch microcoils. The PAVMs varied in size from 1 to 6 cm (mean, 2.5 cm). Five of the lesions were also treated by filling the venous sac with GDCs. Success and outcome were evaluated by means of a review of patient records, angiographic findings, and telephone interview results.

RESULTS

Complete primary occlusion was achieved in eight of nine lesions; repeat embolization resulted in successful occlusion of one lesion. The superselective technique enabled successful embolization in one patient after a previous procedure performed with a 0.035-inch (Gianturco) coil had failed. Filling of the venous sac was performed in the presence of dilated draining veins and enabled successful occlusion of the feeding artery with microcoils in all cases. There were no complications.

CONCLUSION

Superselective embolization with microcatheters allowed easy catheterization and safe coil deployment. Filling of the venous sac reliably prevented systemic migration of GDCs in PAVMs with a large venous component.

Pulmonary arteriovenous malformation

Pulmonary arteriovenous malformations (PAVM) are rare pulmonary vascular anomalies. Although most patients are asymptomatic, PAVMs can cause dyspnoea from right-to-left shunt. Because of paradoxical emboli, various central nervous system complications have been described including stroke and brain abscess. There is a strong association between PAVM and hereditary haemorrhagic telangiectasia. Chest radiography and contrast enhanced computed tomography are essential initial diagnostic tools but pulmonary angiography is the gold standard. Contrast echocardiography is useful for diagnosis and monitoring after treatment. Most patients should be treated. Therapeutic options include angiographic embolisation with metal coil or balloon occlusion and surgical excision.

Interventional occlusion of congenital vascular malformations with the detachable Cook coil system

INTRODUCTION

Nonsurgical closure of pathologic vascular communications can be achieved by coil embolization. Different systems used in patients with congenital heart disease (e.g., patent ductus arteriosus) allow controlled release of the devices. However, they are too stiff for coil occlusion of small or tortuous vessels.

METHODS AND PATIENTS

The new detachable Cook coil system combines flexibility with a simple release control mechanism. Five children, age 8 days to 10 years, underwent heart catheterization for interventional occlusion of different vascular malformations (two coronary artery fistulas, two aortopulmonary collaterals, and one hemangioma). The diameter of the vessels varied between 1.8 mm and 3.6 mm and the length between 10 mm and 22 mm.

RESULTS

Up to four 0.018" soft spiral coils were placed as distally as possible in the feeding vessels. In addition, in two patients, one to three J-shaped coils were placed inside and proximal to spiral coils. Positioning of the coils was controlled easily by radio-opaque markers. Counter-clockwise rotation of the delivery wire provided fast and safe detachment without movement of the detached coils. Control angiograms showed complete occlusion of the vessels within 10 minutes after delivery of coils.

CONCLUSION

Interventional closure of vascular malformations can be successfully obtained with the detachable Cook coil system. This system offers safe and controlled placement of coils, and it works rapidly in an uncomplicated manner.

A hereditary haemorrhagic telangiectasia family with pulmonary involvement is unlinked to the known HHT genes, endoglin and ALK-1

BACKGROUND

Pulmonary arteriovenous malformations (PAVMs) occur in over 25% of patients with the autosomal dominant disorder hereditary haemorrhagic telangiectasia (HHT). Mutations in two genes, endoglin and ALK-1, are known to cause HHT. Each encodes a protein expressed on vascular endothelial cells and involved in signalling by members of the transforming growth factor (TGF)-beta superfamily. To date, PAVMs have not been detected in ALK-1 families. There is evidence from a single HHT family without pulmonary involvement that a third HHT gene may exist. To establish the existence of a further HHT gene responsible for PAVMs, linkage analyses were performed on an expanded PAVM-HHT family in which HHT did not result from endoglin mutations.

METHODS

Family members were assessed clinically to assign HHT disease status and were screened for PAVMs. DNA was extracted from blood obtained from 20 individuals of known disease status. Short tandem repeat polymorphic markers spanning the intervals containing the endoglin and ALK-1 genes were amplified by the polymerase chain reaction using (33)P-labelled oligonucleotide primers, separated by denaturing polyacrylamide gel electrophoresis (PAGE), and the resultant autoradiographs were examined for allele sizes. Linkage analyses were performed using MLINK and GENEHUNTER.

RESULTS

Twelve members spanning four generations were affected with HHT. Two had proven PAVMs, one with a classical appearance, the other exhibiting microscopic PAVMs exacerbated by pregnancy. Two point lod and multipoint lod scores significantly excluded linkage to endoglin and ALK-1 in this pedigree.

CONCLUSIONS

This study confirms the existence of a third HHT locus that accounts for disease in some HHT patients with pulmonary involvement.

Embolotherapy in the bronchial and pulmonary circulations

This two-part article first discusses the role of bronchial artery transcatheter embolotherapy in the management of patients with hemoptysis. Following this discussion, the authors review pulmonary arteriovenous malformations, their embolization, follow-up protocols, and outcome criteria as currently practiced at the authors' Vascular Malformation Center.