OBJECTIVE: Pulmonary arteriovenous malformations (PAVMs) may cause recurrent brain abscess. The primary aim was to determine the prevalence of PAVM amongst survivors of brain abscess. The proportion with cardiac right-to-left shunts was also assessed post hoc.
METHODS: This was a cross-sectional population-based study of adult (≥18 years) survivors of cryptogenic bacterial brain abscess in Denmark from 2007 through 2016. Patients were invited for bubble-echocardiography to detect vascular right-to-left shunting and, if abnormal, subsequent computed tomography thorax for diagnosis of PAVM. Data are presented as n/N (%) or median with interquartile range (IQR).
RESULTS: Study participation was accepted by 47/157 (30%) eligible patients amongst whom two did not appear for scheduled bubble-echocardiography. The median age of participants was 54 years (IQR 45-62) and 19/57 (33%) were females compared with 59 years (IQR 48-68, p = 0.05) and 41/85 females (48%, p = 0.22) in non-participants. Bubble-echocardiography was suggestive of shunt in 10/45 (22%) participants and PAVM was subsequently confirmed by computed tomography in one patient with grade 1 shunting. The corresponding prevalence of PAVM was 2% (95% confidence interval 0.06-11.8) amongst all examined participants. Another 9/45 (20%) were diagnosed with patent in persistent foramen ovale (n = 8) or atrial septum defect (n = 1), which is comparable with the overall prevalence of 25% amongst adults in the Danish background population.
CONCLUSIONS: Undiagnosed PAVM amongst adult survivors of cryptogenic bacterial brain abscess is rare but may be considered in select patients. The prevalence of cardiac right-to-left shunts amongst brain abscess patients corresponds to the prevalence in the general population.

Pulmonary arteriovenous malformations (PAVMs) are most commonly associated with hereditary hemorrhagic telangiectasia (HHT). Patients with PAVMs can present with serious complications including stroke, transient ischemic attack (TIA), and brain abscess. PAVMs are rare in non-HHT patients and little is known about this patient population. The aim of this retrospective study is to better understand clinical presentation and outcomes of PAVMs occurring exclusively in non-HHT patients.
Non-HHT patients with PAVMs at the Mayo Clinic-Rochester between 01/01/2000 and 12/31/2018 were reviewed. Patients with Curacao score > 1 were excluded. Demographics, imaging characteristics, neurological complications, and follow-up imaging were analyzed.
Seventy-seven patients with PAVMs were identified. The mean age at diagnosis was 48.2 ± 18.3 years with female preponderance (59.7%). The majority of PAVMs had lower lobe predominance (66.7%) and were simple and single in 75.3% and 89.6% of cases, respectively. Most patients were asymptomatic (46.8%) with dyspnea being the most common symptom (28.6%). Neurologic complications occurred in 19.5% of patients. The majority of PAVMs were idiopathic (61%). Thirty patients (39%) had one or more possible risk factors including previous thoracic surgery (23.4%), congenital heart disease (19.5%), and chest trauma (10.4%). Embolization was performed in 37 (48.1%) patients and only 4 (5.2%) underwent surgical resection.
Non-HHT PAVMs occur more commonly in females, are most commonly simple and single, and have lower lobe predominance and a high rate of neurologic complications. Potential predisposing risk factors were identified in about 40% of the cases. Clinicians should be aware of the risk of PAVM development in patients with history of chest trauma, congenital heart disease, lung infection/abscess, and thoracic surgery.