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

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.