Insufficiency of the basilar artery - A possible cause of sudden infant death syndrome? Results of a Doppler-sonographic study on 39 infants with apparent life threatening events.

Aim: Hypoperfusion of the brain stem in dependence on head and body position followed by central bradycardia and apnea may be an important cause of sudden infant death syndrome (SIDS). Methods: 39 infants with a mean age of 10.6+/-10.2 weeks (6 days to 11 months) with apparent life threatening events (ALTE) were investigated by cranial Doppler sonography. Additionally 68 healthy infants aged 6 days to 5 months (m 3.7+/-4.1 weeks) were investigated. In all patients flow measurements were performed in one anterior cerebral artery (ACA), both internal carotid arteries (ICA), the basilar artery (BA), and both vertebral arteries (VA) in dependence on head (right/left/neutral) and body position (prone/supine). Results: In healthy infants flow velocities within all intracranial arteries were independent of head and body position. In none of our infants with ALTE significant flow alterations in the ACA and both ICA in dependence on head and body position could be found. In 23 patients with ALTE no dependence of flow in the BA and both VA of head and body position could be shown. In 16 infants however pathologic flow profiles with low flow velocities could be found in the contralateral VA if the head was rotated to the other side. In 9 infants additionally pathologic flow profiles with a dramatic decrease of the flow velocities in the BA could be found. The reduction of the blood flow is caused by compression of the contralateral vertebral artery at the craniocervical junction. Conclusion: The reduction of blood flow in the VA and especially the BA may cause hypoperfusion of the brainstem followed by central bradycardia and apnea. Hypoperfusion of the brainstem in dependence on head and body position may be a significant cause of SIDS. By means of cerebral Dopplersonography infants at risk for SIDS may be detected. Body and head positions which should be avoided can be evaluated noninvasively.