A 51-year-old man presented to the emergency department of our institution with fever, consciousness disorder, and hypoxemia. Magnetic resonance imaging of the brain showed multiple ring-enhancing lesions, which suggested multiple brain abscesses (Fig. 1). Chest roentgenography revealed an abnormal shadow, and contrast computed tomography showed bilateral PAVMs: a 21 × 13 mm nodule in the right S1, preceded by a dilated pulmonary artery of 1 mm in diameter, a 46 × 34 mm nodule in the right S3, preceded by a dilated pulmonary artery of 11 mm in diameter, and a 28 × 25 mm nodule in the left S9, preceded by a dilated pulmonary artery of 1 mm in diameter (Fig. 2). Because of the family history of PAVM, the patient’s history of epistaxis, and the existence of oral mucosa telangiectasia on a physical examination, in addition to PAVMs, he was diagnosed with HHT , and the brain abscess was thought to be caused by right-to-left shunt.
Thanks to the intravenous administration of antibiotics, the brain abscess resolved, and the neurological symptoms improved; however, his hypoxemia was not ameliorated. Because pneumonia also occurred during the treatment of the brain abscess, the patient was intubated and an artificial respirator was used. Despite positive pressure ventilation, his hypoxemia worsened. During pressure-controlled ventilation with driving pressure at 14 cmH2O and PEEP at 6 cmH2O, breathing 100% oxygen, an arterial blood gas analysis revealed a partial pressure of arterial oxygen (PaO2) of 48.8 mmHg. However, changing the ventilator settings (driving pressure at 10 cmH2O and PEEP at 0 cmH2O) improved his oxygenation: PaO2 of 62.8 mmHg while breathing 100% oxygen. We suspected this was because positive pressure ventilation exacerbated the right-to-left shunt.
Even after the improvement of pneumonia with the use of additional antibiotics and ventilator weaning, an arterial blood gas analysis revealed PaO2 of 58.7 mmHg while breathing 70% oxygen. In order to improve his hypoxemia and prevent a relapse of the neurological complications, we planned to treat his PAVMs. We considered that surgical treatment was suitable for the large PAVM in the right S3, due to the safety and certainty of therapy; however, the difficulty in maintaining stable breathing during positive pressure and one-lung ventilation initially prevented us from selecting surgical treatment. Because of the control of the patient’s infectious diseases, transcatheter embolotherapy was performed to treat the left PAVM.
The occlusive coils embolized the left PAVM, which was located in S10, resulting in a slight improvement of the patient’s hypoxemia. After embolizing the largest PAVM on the right, which was located at S3, the patient’s oxygenation improved (Fig. 3a). Some occlusive coils protruded from the PAVM in the S3 and reached the V3; however, these coils were so poor in mobility that we left them untouched. After embolotherapy, an arterial blood gas analysis revealed that the PaO2 had improved to 82.7 mmHg while breathing room air. The patient was able to undergo rehabilitation.
Surgical treatment was performed under one-lung ventilation in the left lateral decubitus position. A 20-cm anterolateral skin incision was made along the fourth intercostal space. We confirmed the PAVMs of S1 and S3 and performed right upper lobectomy. In surgery, we found a coil was present in V3 after dissection of the mediastinal pleura and connective tissue. We therefore transected V1, V2, and V3, to avoid cutting or releasing the coil (Fig. 3b). After the transection of V1, V3, and A1་3, the patient’s oxygenation showed a remarkable improvement.
Transcatheter embolotherapy and surgical treatment were uncomplicated. The patient’s PaO2 level while breathing 100% oxygen increased up to 452 mmHg, and his dyspnea was ameliorated. Using pulmonary shunt fraction measurement with the 100% oxygen method, the shunt fraction was found to have improved from 27.9–11.8%. He was discharged to home on the 37th postoperative day after rehabilitation.