Pulmonary arteriovenous malformations (PAVMs) are fistulous connections between pulmonary arteries and veins, associated with hereditary hemorrhagic telangiectasia. It can be associated with a wide range of complications. Contrast-enhanced computed tomography is the best noninvasive diagnosis modality. Treatment is recommended for symptomatic patients or those having a feeding artery diameter superior to 3 mm. We present here the case of a 69-year-old man with a complex PAVM, peripherally localized with a feeding artery diameter bigger than 3 mm intentionally treated via an open middle lobe wedge resection via axillary mini thoracotomy over embolotherapy, showing that it comes with less risk and at a lower cost.
Pulmonary arteriovenous malformations (PAVMs) are fistulous connections between pulmonary arteries and veins. Though isolated cases have been reported, hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu disease, is present in more than half of the cases . Osler-Weber-Rendu disease is an autosomal dominant disorder characterized by multiple mucocutaneous telangiectasias. PAVMs can be associated with different types of complications ranging from paradoxical embolization (stroke or brain abscess) and pulmonary hemorrhage to exercise intolerance . Treatment is recommended for symptomatic patients or those having a feeding artery diameter bigger than 3 mm . Transcatheter embolotherapy or detachable balloons are widely performed. Percutaneous treatment is technically challenging because of the concomitant lungs and heart movements. It is even impossible in large PAVMs. Moreover, such interventions can be expensive. Open surgical excision is therefore preferred in specific cases. We report hereunder the case of a 69-year-old man with a large PAVM on the right middle lobe discovered during the workup of a recent cough. The patient underwent a successful open middle lobe wedge resection via axillary thoracotomy. An open surgical approach was preferred over an endovascular approach as it carried less risk at a lower cost. Written informed consent was obtained from the patient for publication of this case report and accompanying images.
A 69-year-old man presented to our clinic for a suspected mass of the right lung on chest radiography. He was a heavy smoker (50 pack-years) with diabetes, dyslipidemia, and obesity (body mass index = 31.1), but without any history of hemoptysis. Physical examination was unremarkable. Arterial blood gas was normal (pH = 7.43, partial pressure of oxygen PaO2 = 85 mm Hg, partial pressure of carbon dioxide PaCO2 = 40 mm Hg) and so were routine pulmonary function tests (FEV1 = 110% and DLCO = 139%).
Based on the patient’s smoking history, a contrast-enhanced chest computed tomography (CT) scan was performed (shown in Fig. 1). It showed a complex 45 × 20 mm PAVM at the base of the right middle pulmonary lobe with multiple feeding arteries and draining veins. The PAVM had pulmonary and systemic feeding arteries from branches of the right middle lobe pulmonary artery (4 mm in diameter), the internal thoracic artery (4 mm in diameter), and the diaphragmatic artery (2 mm in diameter).
An open middle lobe wedge resection via axillary mini thoracotomy was performed for a complete ablation of the malformation (shown in Fig. 2). Postoperative course was uneventful, and the patient was discharged on day 5. Pathology report confirmed the arteriovenous nature of the malformation and excluded the presence of malignancy.
PAVM pathogenesis is unknown. Three different possibilities are evoked in the literature. Gossage and Kanj suggested that the dilatation of thin-walled capillary sacs results from a defect in terminal arterial loops . For Anabtawi et al. , it could be the consequence of an in utero resorption defect of the vascular septae in vascular plexuses or a failed capillary development during fetal growth.
There are two types of PAVMs: simple and complex. In contrast to simple PAVMs, complex PAVMs have multiple feeding arteries and draining veins . PAVMs can present as a single or multiple lesions. Even bilateral lesions have been reported . Lower pulmonary lobe is a preferential localization . Women are more affected than men . Association with HHT is found in 70% of cases . A pulmonary location has already been described . In our case, the patient presented a complex PAVM in the right middle pulmonary lobe.
In any patient with PAVM, it is important to search for nosebleeds in the patient’s personal and familial history. Spontaneous and recurrent nosebleeds are a very common finding in patients with HHT . No personal or familial history of nosebleeds was reported by our patient. Brain abscesses are reported in 6% of the patients when natural pulmonary vascular filter are bypassed by bacteria . Two life-threatening complications are hemoptysis and  hemothorax. While rupture of a subpleural PAVM may result in a hemothorax, intrabronchial rupture of PAVM, or endobronchial telangiectasia may result in hemoptysis .
Contrast-enhanced CT is the best noninvasive diagnosis modality as it defines the vascular anatomy of PAVMs. Chest radiography is crucial for diagnosing and monitoring patients with PAVMs. Arterial blood gas testing is helpful for the diagnosis since many patients have hypoxemia that is not improved by supplemental oxygenation because of the fixed right-to-left shunt . A high incidence of orthodexia is also reported . For the case we present here, we suspected the presence of a pulmonary mass on the chest radiography, leading us to perform a chest CT and make the diagnosis. His arterial blood gas was unremarkable, and no orthodexia was reported by him.
We did not find any consensus guidelines or statements on PAVMs’ management. Treatment depends on the malformation size, number, and location. The patient’s general condition can obviously influence the decision. Signs like a progressive enlargement of the lesion, paradoxical embolization, or symptomatic hypoxemia are considered to be indications for an invasive treatment . Feeding artery diameter and clinical symptoms also influence decision-making process, as the risk of complications rise with the increase in feeding artery diameter . A feeding artery diameter of less than 2 mm carries no risk for paradoxical embolization. Complications are uncommon when diameter is between 2 and 3 mm. A feeding artery diameter of 3 mm or more is generally an indication for treatment, as well as any symptomatic PAVM. Thus, asymptomatic PAVMs with a feeding artery diameter under 2 mm are not treated given the low risk of complications . The reported case here had large and multiple feeding arteries and veins, thus increasing the risk of complications.
To avoid potentially fatal complications, the most radical and effective treatment should be used. Surgical resection was considered to be the sole choice with many possibilities ranging from ligation and local excision to pneumonectomy. More recently, percutaneous transcatheter embolization has been widely used, with the advent of endovascular techniques. Though this technique comes at a higher cost than surgery, it is less invasive with a lower complication rate . However, with the constant movement of the heart and lungs, technical challenges such as catheter dislodgement need to be considered. It is also to be noted that endovascular approach might be inappropriate in large PAVMs . For large, peripherally localized lesions, as in our case (45 × 20 mm), a pulmonary wedge resection with ligation of the supplying arteries and vein can be a better option. Our patient’s PAVM had three main feeding arteries: a pulmonary artery (4 mm in diameter), the right internal thoracic artery (4 mm in diameter), and a right diaphragmatic artery (2 mm in diameter). PAVMs’ surgery carries the same risks as any other thoracic surgery. It is however associated with minimal morbidity and mortality and rare postoperative recurrences when performed in well-selected patients . In our experience, patients with large peripheral lesions and multiple feeding arteries are better candidates for surgical resection, while patients with small central lesions are better candidates for endovascular treatment. The lower cost of surgery is an added advantage.
We believe that in selected PAVM cases surgery should still be considered. In case of a single peripheral localization and the presence of several feeding arteries with a diameter larger than 3 mm, surgery is a safe approach that carries less risk at a lower cost.
Statement of Ethics
The case report was prepared and complied with the guidelines for human studies and was conducted ethically in accordance with the World Medical Association Declaration of Helsinki. Written informed consent was obtained from the patient for publication of the case report and the accompanied images. The study was approved by the Hotel-Dieu de France (HDF) Ethics Committee, Saint Joseph University of Beirut, Ref CEHDF2196 and dated July 24, 2023.
Conflict of Interest Statement
The authors have no conflicts of interest to declare.
No funding was received for this study.
Karim Nehme: work design, data acquisition, data analysis, manuscript writing, manuscript revision, final approval, and agreement to be accountable. Lamisse Karam: data analysis, manuscript writing, manuscript revision, final approval, and agreement to be accountable. Joseph Nakad: manuscript revision, final approval, and agreement to be accountable. Nader Saad: data acquisition, data analysis, manuscript revision, final approval, and agreement to be accountable. Georges Tabet: work design, data acquisition, data analysis, manuscript revision, final approval, and agreement to be accountable.
Data Availability Statement
All data analyzed during this study are included in this article. Further inquiries can be directed to the corresponding author.