Pulmonary Arteriovenous Malformation and Its Vascular Mimickers

Thrombus rooting in the pulmonary arteriovenous fistula in a patient with cryptogenic stroke, a case report

BACKGROUND

Cryptogenic stroke constitutes approximately 40% of ischemic strokes in young adults, imposing a significant socioeconomic burden. However, the source of embolus has been specifically investigated in a few number of studies. In this report, We document the first case of a cryptogenic stroke associated with a pulmonary arteriovenous fistula (PAVF), providing evidence of mural thrombus formation within the PAVF vessel.

CASE PRESENTATION

A 52-year-old woman present with sudden-onset blurriness, right-sided numbness and paresthesia, speech difficulties, and salivation. It was confirmed as embolic stroke with magnetic resonance imaging. No evidence of cerebral arteriosclerosis or stenosis was identified, and cardiogenic embolism was ruled out. Further investigation was conducted to determine the cause of the anomalous embolism. A right-to-left shunt was detected using trans-cranial Doppler and transthoracic echocardiogram. Pulmonary arteriography revealed a simple PAVF. Optical coherence tomography (OCT) was used to examine the interior structure of the fistula vessel, revealing the presence of mural thrombus and a rough endangium.

CONCLUSIONS

This case provides the initial evidence regarding the location of thrombus formation assessed and raises the awareness of a potential emboligenic mechanism in PAVF.

Pulmonary arteriovenous malformation causing lung sequestration and media infarction: a case report

Pulmonary arteriovenous malformations (PAVMs) are rare vascular malformations of the lungs. Direct communication of pulmonary arteries to pulmonary veins is the defining characteristic allowing venous blood to bypass the pulmonary capillary system and avoiding an efficient oxygenation process. The complexity of the pathology lies not only in the variety of its manifestations, but also in the choice of the most appropriate and effective treatment. We present a case of a complex PAVM associated with a persistent foramen ovale, with stroke as the onset symptom. Despite timely multidisciplinary treatment of the malformation, a potentially fatal pulmonary complication occurred, highlighting the critical importance of early, interdisciplinary management and ongoing follow-up of PAVMs, particularly in preventing life-threatening outcomes.

Recurrent Hematochezia Due to a Rectal Fistula Caused by a Left Internal Iliac Artery Aneurysm

Arterio-enteric fistulas (AEFs) are a rare cause of gastrointestinal bleeding involving direct communication between an artery and the intestinal tract. The duodenum is the most common fistula site for AEFs, but none of the rectal cases are known. We present the case of an elderly man with hematochezia due to a rectal fistula caused by a left internal iliac artery aneurysm, which was detected on contrast-enhanced computed tomography (CT), showing typical fistula formation and ectopic gas images. This case highlights the importance of considering the occurrence of rare but potentially fatal AEFs in elderly patients with hematochezia and that the timely performance of contrast-enhanced CT is critical for an accurate diagnosis.

The "pseudo-pulmonary AVM sign": an aid to the diagnosis of histoplasmosis and differentiation from pulmonary arteriovenous malformations

The diagnostic algorithm for histoplasmosis highlights the importance of imaging and emphasizes the role of the radiologist in the diagnostic workup. Here we describe a case series of patients with a novel sign of lung involvement in histoplasmosis which we have coined the Pseudo-Pulmonary Arteriovenous Malformation (PAVM) sign, the usage of which would help in the imaging diagnosis of histoplasmosis aid by distinguishing it from PAVMs. PAVMs carry risk for serious complications such as systemic emboli and may require treatment; whereas, histoplasmomas do not. Differentiation of histoplasmosis from other diagnoses can be made with laboratory studies, but may require bronchoscopy, biopsy, or both. Meanwhile, PAVMs should not be biopsied due to risk of bleeding. For these reasons, distinguishing PAVMs and histoplasmosis radiologically therefore greatly impacts clinical management, and it is important for radiologists to be aware of this appearance of histoplasmosis to avoid misinterpretation as PAVM and effectively inform clinical care.

Neurological and cardiopulmonary manifestations of pulmonary arteriovenous malformations

Pulmonary arteriovenous malformations (PAVMs) are direct pulmonary artery-to-vein connections without pulmonary capillaries that result in intrapulmonary right-to-left blood shunts. Although most patients with PAVMs may be entirely asymptomatic, PAVMs can induce a series of complications involving the neurological, cardiovascular, and respiratory systems that can lead to catastrophic and often fatal clinical sequelae. In this study we review the available literature and summarize the reported PAVM-related complications among patients with PAVMs. The reviewed studies included observational studies, case studies, prospective studies, and cohort studies, and we provide an overview of PAVM-related neurological and cardiopulmonary manifestations, including stroke, cerebral abscess, transient ischemic attack, cerebral hemorrhage, migraine, seizure, dizziness, cardiac failure, arrhythmia, myocardial infarction, cough, hypoxemia, dyspnea, respiratory failure, hemoptysis, and hemothorax. Identifying and treating PAVMs before the presentation of major complication is important because this can prevent the occurrence of complications and can result in better outcomes. PAVM patients should thus be better evaluated and managed by a multidisciplinary team because they may be in a treatable phase prior to their condition becoming life-threatening.

Bilateral Pulmonary Arteriovenous Malformations: Challenges in a Rare and Complex Case

Pulmonary arteriovenous malformations (PAVMs) are abnormal vascular connections between the pulmonary arteries and pulmonary veins. Despite their relatively uncommon incidence, PAVMs should be considered in the differential diagnosis of children presenting with cyanosis due to the life-threatening complications posed by paradoxical emboli. The primary management approach involves eliminating the abnormal connections, either through surgical or endovascular methods. We present a case of a five-year-old boy who was seen in the Outpatient Department with cyanosis of the lips and nail beds persisting for eight months. On examination, grade 3 clubbing was noted. Imaging and subsequent angiography revealed multiple bilateral diffuse AVMs, which were treated using an endovascular approach.

Large pulmonary arteriovenous malformation lost to follow-up with 10 years of asymptomatic interval growth: A case report

Pulmonary arteriovenous malformations, previously considered a rare condition, have been increasingly identified in asymptomatic patients over the past 2 decades. Usually congenital and associated with hereditary hemorrhagic telangiectasia, these fistulae result in right-to-left shunting of blood by abnormal communication of pulmonary arteries and veins lacking capillary beds. Clinical findings of right-to-left shunting in the presence of feeding and draining vessels identified on imaging confirm the diagnosis, for which the first-line therapy is embolization. This report highlights the presentation and management of a large asymptomatic PAVM detected incidentally in a patient who was lost to follow-up for 10 years and represented with acute hypoxic respiratory failure secondary to a viral infection with an interval increase of PAVM size.

An Alternative Endovascular Technique for Treatment of Pulmonary Arteriovenous Malformation: Microballoon-occluded Transcatheter Embolization Using n-butyl-2-cyanoacrylate

PURPOSE

To investigate the safety and efficacy of microballoon-occluded transcatheter embolization using n-butyl-2-cyanoacrylate (NBCA) in patients with a single pulmonary arteriovenous malformation (PAVM).

METHODS

From November 2017 to November 2020, this retrospective study included 38 previously untreated patients with a single PAVM who underwent microballoon-occluded transcatheter embolization using NBCA. All 38 patients had follow-up that included simple chest radiography and contrast-enhanced chest computed tomography (CT).

RESULTS

A microballoon was successfully placed in a feeding artery of the PAVM to control the delivery of the NBCA cast in all 38 patients, with complete embolization of sacs and the feeding artery achieved in all cases. The mean diameters of the feeding artery, sac, and draining vein were 3.9 ± 0.9 mm, 7.5 ± 2.6 mm, and 4.6 ± 1.3 mm, respectively. A fixed 1:2 NBCA/Lipiodol ratio was used, and the mean amount of embolic mixture per patient was 1.4 mL (range 0.6-2.2 mL). There were no complications related to microballoon adhesion and non-target embolization of the systemic circulation. Follow-up CT in all 38 patients with a mean delay of 34.5 ± 8.8 months (range 20.7-56.5 months) showed no continued perfusion of the PAVM.

CONCLUSION

In our hands, microballoon-occluded n-butyl-2-cyanoacrylate embolization seemed to be safe and appeared to be clinically effective in patients with simple and complex types of single PAVM. Therefore, the present technique has the potential to become a standard treatment for a single PAVM.

Complex Pulmonary Arteriovenous Fistula Presented With Ventricular Tachycardia and Type 2 Acute Myocardial Infarction

Pulmonary arteriovenous fistula (PAVF) is a rare congenital vascular malformation primarily manifested as dyspnea, migraine, ischemic stroke, hemoptysis, and nervous system complications. However, in our case, an 18-year-old male patient with PAVF presented with sudden onset of ventricular tachycardia and type 2 acute myocardial infarction as initial symptoms. A diagnosis was achieved through pulmonary artery computer tomography angiography (CTA) and three-dimensional (3D) computed tomography (CT) reconstruction, revealing a complex and giant PAVF. Following multidisciplinary team (MDT) consultation, the patient underwent thoracoscopic surgery and experienced a successful recovery during follow-up.

A Microsurgical Arteriovenous Malformation Model on Saphenous Vessels in the Rat

Arteriovenous malformation (AVM) is an anomaly of blood vessel formation. Numerous models have been established to understand the nature of AVM. These models have limitations in terms of the diameter of the vessels used and the impact on the circulatory system. Our goal was to establish an AVM model that does not cause prompt and significant hemodynamic and cardiac alterations but is feasible for follow-up of the AVM's progression. Sixteen female rats were randomly divided into sham-operated and AVM groups. In the AVM group, the saphenous vein and artery were interconnected using microsurgical techniques. The animals were followed up for 12 weeks. Anastomosis patency and the structural and hemodynamic changes of the heart were monitored. The hearts and vessels were histologically analyzed. During the follow-up period, shunts remained unobstructed. Systolic, diastolic, mean arterial pressure, and heart rate values slightly and non-significantly decreased in the AVM group. Echocardiogram results indicated minor systolic function impact, with slight and insignificant changes in aortic pressure and blood velocity, and minimal left ventricular wall enlargement. The small-caliber saphenous AVM model does not cause acute hemodynamic changes. Moderate but progressive alterations and venous dilatation confirmed AVM-like features. The model seems to be suitable for studying further the progression, enlargement, or destabilization of AVM.

Overview of peripheral arteriovenous malformations: From diagnosis to treatment methods

Based on the latest classification by the International Society for the Study of Vascular Anomalies in 2018, vascular malformations (VMs) can be categorized into simple, combined VMs of major named vessels, and VMs associated with other anomalies. Simple VMs include lymphatic, venous, capillary, and arteriovenous malformations (AVMs). AVMs represent disorders of direct arteriovenous shunts caused by the absence of a capillary bed between the involved arteries and veins. This abnormal vascular communication causes arterial blood to accumulate in the venous vessels, thus resulting in venous hypertension and characteristic clinical manifestations, such as pulsation, tremors, and elevated temperature. AVMs can occur sporadically or as manifestations of syndromic lesions and are considered among the most complex and challenging VMs. The diagnosis and treatment of AVMs can vary depending on the lesion location and associated clinical symptoms, thus complicating their management. Herein, we discuss peripheral AVMs in terms of their clinical manifestations, imaging examinations, and staging systems to provide a comprehensive reference for the treatment, evaluation methods, and follow-up procedures for this vascular anomaly.

Case report: video-assisted thoracoscopic surgery for pulmonary arteriovenous malformation using near-infrared fluorescence with indocyanine green

BACKGROUND

Pulmonary arteriovenous malformation (PAVM) is an abnormal communication between pulmonary vasculatures and has an unclear boundary with surrounding lung tissues. At present, surgeons can only determine its location by preoperative imaging and intraoperative palpation, despite its soft texture. Indocyanine green(ICG), a near-infrared fluorophore, has been demonstrated useful in the accurate identification of vascular tissue. Therefore, we explored its application in PAVM cases.

CASE PRESENTATION

We present two PAVM cases using near-infrared fluorescence (NIF) with 25 mg ICG at 5 mg/ml to achieve intraoperative visualization of the lesion in video-assisted thoracoscopic surgery (VATS). Under the NIF mode, ICG systemic injection led to successive signaling of the anomaly and normal tissues in merely 10 s, which helped us distinguish them efficiently and precisely. A peak signal-to-background ratio of 2.2 confirmed the significant fluorescence difference and excluded interference from carbon dust.

CONCLUSIONS

We are the first to report the use of such an approach in delineating the margin of vascular malformation with high contrast, and this new finding may help minimize the damage to lung function in PAVM treatment. Further exploration and validation are needed to determine its role.

Vascular Malformations and Tumors: A Review of Classification and Imaging Features for Cardiothoracic Radiologists

The International Society for the Study of Vascular Anomalies (ISSVA) classification is a comprehensive histology-based scheme that was updated in 2018. It is important for cardiothoracic imagers to understand this classification to ensure that accurate terminology is used and that archaic terms are avoided when vascular lesions are described. Knowledge of the various malformations (including common conditions, such as venous malformation, arteriovenous fistula, and arteriovenous malformation) and vascular tumors allows for timely diagnosis and appropriate management. This review describes various vascular anomalies, in accordance with ISSVA classification and terminology; highlights key imaging features associated with each; and discusses the role of different imaging modalities. Keywords: Pulmonary, Soft Tissues/Skin, Vascular, Arteriovenous Malformation © RSNA, 2023.

Effects of Shared Decision-Making with a Patient Decision Aid for Postangiography Hemostasis Method Selection: A Randomized Controlled Trial

PURPOSE

To evaluate the effects of shared decision-making (SDM) with a patient decision aid (PtDA) on hemostasis device selection and reduction of decisional conflicts in patients undergoing transfemoral angiography.

MATERIALS AND METHODS

Patients undergoing angiography were randomized to receive either a standard explanation or the process aid of PtDA for choosing hemostasis devices. The decisional conflict was assessed using the 4-item Sure of myself; Understand information; Risk-benefit ratio; Encouragement (SURE) scale. Differences in demographic variables, clinical variables, and final choice of hemostasis devices were compared via univariate and multivariate logistic regression analyses.

RESULTS

In total, 158 patients were included-80 in the PtDA group and 78 in the standard group. No difference was found between the 2 groups in terms of patient demographic and clinical variables. The PtDA group scored better on all questions of the SURE scale both individually and collaboratively (P <.001). PtDA intervention (P =.031) and reason for angiography (P =.0006) were the main variables that influenced patient hemostasis device choice in the univariate logistic regression analysis. Reason for angiography remained the only deciding factor that affected patient choice in the multivariate logistic regression analysis (P =.015).

CONCLUSIONS

Step-by-step guidance and pictorial explanation with the assistance of PtDA led to improvements in patient knowledge but showed no significant impact in multivariate analysis for the influence on the choice of hemostasis device.

Embolization in Pediatric Patients: A Comprehensive Review of Indications, Procedures, and Clinical Outcomes

Embolization in pediatric patients encompasses a large spectrum of indications, ranging from the elective treatment of congenital diseases of the cardiovascular system to the urgent management of acute hemorrhagic conditions. In particular, the endovascular treatment of central and peripheral vascular malformations and hypervascular tumors represents a wide chapter for both congenital and acquired situations. Thanks to the progressive availability of low-profile endovascular devices and new embolic materials, the mini-invasive approach has gradually overtaken surgery. In this review, the main embolization procedures will be illustrated and discussed, with a focus on clinical indications and expected outcomes. The most recent mini-invasive techniques will be described, with hints on the cutting-edge devices and embolic materials.