Changes in cerebral hemodynamic and cognitive parameters after external carotid-internal carotid bypass surgery in patients with severe steno-occlusive disease: a pilot study

Abstract

Background: The direct impact of external carotid-internal carotid (EC-IC) bypass surgery on cognition of patients with severe steno-occlusive disease of internal carotid (ICA) or middle cerebral artery (MCA) is unknown. In this pilot study, we evaluated changes in cerebral hemodynamic and cognition in these patients.

Methods: Patients with severe steno-occlusive disease and impaired cerebral vasodilatory reserve (CVR) with transcranial Doppler (TCD) breath holding index (BHI) and acetazolamide-challenged HMPAO-Single Photon Emission Tomographic (SPECT) imaging were offered EC-IC bypass surgery. CVR and cognitive performance using a formal neuropsychological battery were evaluated before and 3-6 months after surgery.

Results: Nine patients and 9 matched controls were recruited. Significant CVR improvement from TCD-BHI [median 0 (Inter-quartile range IQR 0.45) to 1.10 (IQR 0.73), p<0.001] and SPECT (p<0.001) was observed in surgery patients. EC-IC bypass patients had significant improvement in verbal memory (p=0.037) and executive function (p=0.043) and a trend of improvement in visual memory (p=0.052) compared to controls.

Conclusion: EC-IC bypass surgery in carefully selected patients could improve cerebral hemodynamics and verbal memory and executive function.