Measurement of oxygen extraction fraction by blood sampling to estimate severe cerebral hemodynamic failure and anticipate cerebral hyperperfusion syndrome following carotid artery stenting

Background Cerebral hyperperfusion syndrome (CHS) is likely to occur after carotid revascularization in patients with stage 2 hemodynamic failure (st2HF), in whom the oxygen extraction fraction (OEF) increases. Objective The purpose of our study was to investigate whether measurement of the global cerebral OEF (gcOEF) by blood sampling can be used to estimate st2HF and anticipate CHS following carotid artery stenting (CAS). Methods The OEF was calculated by blood sampling just before and after elective CAS. Data were collected prospectively. Patients who underwent elective CAS and gcOEF calculation were included in the study. Patients’ baseline features, pre-CAS gcOEF, post-CAS gcOEF, and incidence of CHS (defined as headache, seizure, focal neurologic deficits, and/or restlessness) were evaluated. Results 141 patients met the inclusion criteria and 134 patients were analyzed. Median pre-CAS gcOEF and post-CAS gcOEF were 0.41 and 0.42, respectively. Nine patients developed CHS. Median pre-CAS gcOEF was higher in patients with than in those without CHS (Mann–Whitney U test, P<0.05), but median post-CAS gcOEF was not significantly higher in patients with CHS (P=0.058). Scattergrams of patients with and without CHS showed that the cut-off values of the pre-CAS gcOEF and post-CAS gcOEF for anticipation of CHS were 0.46 (P<0.01) and 0.49 (P<0.001), respectively. Conclusion Elevation of the pre-CAS or post-CAS gcOEF by blood sampling allowed for anticipation of CHS following CAS. Elevation of the pre-CAS gcOEF might be associated with st2HF.