Screening for pulmonary arteriovenous malformations - Contrast echocardiography versus pulse oximetry

Pulmonary arteriovenous malformations (PAVM) cause right-to-left shunt and imply risk of paradoxical embolism and cerebral abscess. These complication s can be prevented by appropriate treatment. Detection of PAVMs is therefor e important, so simple and reliable screening methods are needed for this p urpose. The aim of this investigation was to compare pulse oximetry and con trast echocardiography as screening tools for detection of pulmonary arteri ovenous malformations. Eighty-five hereditary haemorrhagic telangiectasia ( HHT) patients and first-degree relatives identified in a comprehensive stud y of HHT-families in the county of Funen, Denmark, were investigated. Stand ing and supine pulse oximetry in room air was performed in all subjects, an d in subjects with symptoms and/or abnormal pulse oximetry in room air, sup ine pulse oximetry breathing 100% oxygen was also performed. Transthoracic echocardiography with intravenous injection of echo contrast was performed in all subjects. Outcome measures were oxygen saturation change >2% units o n changing body position and echo contrast observed in the left-sided heart chambers. Positive contrast echocardiography indicating the presence of PA VM was found in 47 subjects, whereas pulse oximetry was abnormal in only 16 . The results strongly suggest that contrast echocardiography is a more sen sitive screening tool for PAVMs than pulse oximetry.