A rigid bronchoscopy and endobronchial ultrasound (EBUS) with biopsy and excision of the endobronchial mass was planned. At the time of rigid bronchoscopy, the radial EBUS probe malfunctioned and did not provide images. Examination revealed a shiny, nonpulsatile mass in the right middle lobe orifice. It was rubbery in consistency and difficult to grip with forceps. After an uneventful first biopsy, the second biopsy resulted in significant bleeding. The right middle lobe bronchus was packed with cottonelles of 1×4-cm gauze. Bleeding persisted, requiring packing of the right bronchus intermedius and tamponade with the rigid scope.
Intraoperative thoracic surgical consultation was obtained and the patient was taken for thoracotomy and right middle lobectomy. Before the surgery, the rigid bronchoscope was exchanged over a silastic catheter for an endotracheal tube, selectively intubating the left mainstem bronchus. The patient underwent right middle lobectomy with no active bleeding visualized. Once the surgeons were ready to suture the right middle lobe stump, they removed the endobronchial packing. Upon removal of the packing, there was arterial bleeding into the operative field. Careful dissection was carried out revealing 2 large bronchial arteries and a large communicating vein. Ligation of these resulted in cessation of bleeding. The thoracotomy wound was closed and the remaining packing was removed with a rigid bronchoscope. Finally, blood clots were lavaged from the right lung. The patient's postoperative course was uncomplicated and she was discharged home on postoperative day 5. The pathology report from the biopsy of the mass taken with the rigid bronchoscope revealed bronchial wall with mild chronic inflammation and no malignancy.
Investigators have referred to bronchial arteriovenous malformations (AVMs) by a variety of terms in the past, including malformation, angioma, racemose hemangioma, and fistula.1–6 AVMs in the lung with a feeding vessel from the systemic circulation are rare, occurring in roughly 4% of all cases.2 Moreover, when a systemic feeding vessel is part of an AVM, it is rarely the bronchial artery that is involved.2 Thus, an endobronchial AVM involving the bronchial artery is a very rare anomaly, not well described in the literature.
Previous reports indicate that such lesions may present at any age and occur more commonly in men.1,2 The right lung is involved more often than the left, and lesions are usually unilateral and solitary.1–3 Patients with bronchial AVM often present with recurrent hemoptysis and cough. Many episodes are described as potentially life-threatening; it is rare to find a bronchial AVM in an asymptomatic patient.2,4 Bronchial AVMs should be distinguished from the better known pulmonary AVMs that are often accompanied by cyanosis, clubbing as part of hemorrhagic hereditary telangiectasia.5 Patients with bronchial AVM do not share these features.
Bronchial AVMs may be classified as either primary (congenital) or secondary (owing to inflammatory disease or lung neoplasm).6 Most of the bronchial AVMs described in the literature have been classified as primary.1–4,6 As bronchial artery AVMs are subject to systemic pressure, it is thought that they may undergo progressive enlargement over time. In some cases, such enlargement may lead to necrosis of the vessel wall with resultant rupture and massive hemoptysis.7
There are no reliable bronchoscopic characteristics that distinguish bronchial AVMs from other endobronchial lesions. Pathologic examination of bronchial AVMs usually reveals a tortuous dysplastic artery with tiny vessels proliferating in the airway submucosa that are covered with normal epithelium.4 During bronchoscopy, the light from the bronchoscope is reflected, absorbed, and scattered. The light that is absorbed may penetrate the epithelium as far as the submucosal layer to a depth of 0.5 mm.4,8 Thus, the AVM may not be seen through the normal epithelium by bronchoscopy if the vessels lie more than 0.5 mm from the lumen. Indeed, a red and pulsatile dysplastic artery is not usually appreciated during bronchoscopy.4,9
Soda et al4 described a patient with a bronchial AVM in whom there was a protrusion of the AVM into the airway resulting in airway obstruction, as was the case in our patient. Their patient had previously undergone bronchoscopy in which a few engorged vessels were noted in the area of the endobronchial lesion; however, no pulsatile vessels were appreciated. Subsequent bronchial brushing resulted in brisk bleeding and termination of the procedure. This history gave Soda's group a clue to the diagnosis, which was established with a bronchial arteriogram. Katoh et al9 described 7 patients with bronchial artery lesions and hemoptysis. Bronchoscopic findings in 5 of 7 patients showed a bulging lesion whereas the remaining 2 patients demonstrated an endobronchial mass. A bulging lesion on bronchoscopy corresponded to either an aneurysm or hypervascular area in the bronchial arteriogram. The mass lesions corresponded to either a hypervascular area or a focal dilatation on bronchial arteriogram. Upon treatment with bronchial artery embolization for hemoptysis in these patients, the lesions either diminished or disappeared bronchoscopically.
Iwasaki et al1 described a 44-year-old woman with repeated hemoptysis for 7 years. Pulmonary angiography revealed enlarged and convoluted vessels with shunts between the bronchial and pulmonary arteries on right and left bronchial arteries. These findings confirmed a diagnosis of AVM of the bronchial artery. She was treated with embolization of the right bronchial arteries. One year later, she had an episode of hemoptysis and was found to have reestablishment of a shunt between bronchial and pulmonary arteries. She underwent a right thoracotomy for the resection of this lesion. This experience mirrored that of Sukoh et al3 who summarized the Japanese experience of bronchial artery AVM. In their series, the right lung was involved more than the left and lesions were usually unilateral. Polypoid lesions covered with normal mucosa were seen on bronchoscopy in 10 out of 13 patients. Finally, Pouwels et al2 reported a case of a young man who presented with massive hemoptysis and was diagnosed with a bronchial artery AVM after bronchial artery arteriogram. The arteriogram revealed a hypertrophic and tortuous right bronchial artery with hypertrophic branches going toward a large malformation in the right middle and lower lobes. He underwent right middle and lower lobectomy with resolution of hemoptysis.
As it is difficult to distinguish bronchial AVM from other endobronchial lesions, EBUS is an invaluable tool for the bronchoscopist. EBUS allows physicians to visualize the structures surrounding the airway and easily delineates blood vessels, tumors, and lymph nodes.8 Kuo et al10 reported a case in which EBUS was employed to diagnose pulmonary AVM associated with hemorrhagic hereditary telangiectasia. Under EBUS, the lesion was described as a hypoechoic density with a sharp margin and pulsation surrounded by lung parenchyma. If our EBUS probe had functioned properly, it is likely that the dilated bronchial vessels would have been detected and the biopsy could have been avoided.
Multidetector computerized tomography (MDCT) angiography is also a useful method for evaluating the hemodynamics and morphology of abnormal vessels. Uchiyama et al6 reported diagnosing a case of bronchial AVM using MDCT angiography. Their technique was elegant and resulted in the construction of 3-dimensional fusion images obtained by superimposition of the arterial phase on the venous phase. An abnormal course and form of the bronchial artery with a left-to-right shunt forming a communication between the bronchial artery and the pulmonary artery was detected.
In conclusion, the bronchoscopist should keep in mind the possibility of a bronchial AVM when encountering an endobronchial lesion. Clues to the presence of an AVM include irregular out pouching of the bronchial wall and engorgement of superficial vessels. If one suspects a bronchial AVM in a patient, MDCT angiography, bronchial arteriography, and EBUS are useful tools in diagnosis and may prevent biopsy with resultant life-threatening hemorrhage. On the basis of our review of the literature, it seems that vascular embolization and surgical resection are reasonable treatment options, though surgical resection may be necessary for patients with recurrent or life-threatening hemoptysis.
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Keywords:© 2008 Lippincott Williams & Wilkins, Inc.
bronchial artery; arteriovenous malformation; bleeding; bronchoscopy; endobronchial mass; endobronchial ultrasound; surgery