Impact of vertebral artery disease on dynamic cerebral autoregulation

Objectives – This study applied dynamic cerebral autoregulation (DCA) testing distally to severe bilateral vertebral artery disease (BVAD). Methods – Using continuous monitoring of beat‐to‐beat blood pressure and transcranial Doppler of the posterior cerebral arteries (PCA) were examined in 20 patients with BVAD and 22 controls. DCA testing was based on the ‘high‐pass filter model’, which predicts a positive phase relationship between spontaneous oscillations (M‐waves 3–9 cpm and R‐waves 9–20 cpm) in blood pressure and cerebral blood flow velocity. Results – In patients with BVAD, DCA testing detected autoregulatory deficits of different degrees. The lowest M‐wave phase shift angles were found in the PCA territory distally to intracranial BVAD. Conclusion – This study suggests that DCA testing of the PCA could help to quantify the hemodynamic impact of BVAD. It highlights the relevance of functional TCD sonography as a useful diagnostic tool for the hemodynamic evaluation of vertebrobasilar disease.