RESUMO
Dialysis grafts may lead to major hyperperfusion in the graft arm and to hypertrophic, hypervolemic cardiomyopathy. No data have been published concerning the impact of dialysis grafts on the cerebral perfusion in relation to a potential carotid steal syndrome, possibly causing neurologic or neuropsychologic symptoms. In 30 patients (32 to 74 years old) with dialysis grafts we studied the following hemodynamic parameters in the brachial and common carotid arteries bilaterally: Flow velocities (spectral Doppler sonography), diameter (B-mode) and volume flow (color M-mode) with a color duplex system (Philips P700). Volume flow in the brachial arteries of the graft arm averaged 1032 ml/min (range, 158 to 2854 ml/min) as compared to 42 ml/min (range, 15 to 108 ml/min) in the nongraft arm. Almost identical volume flow data could be seen in both common carotid arteries (418 versus 421 ml/min) with no evidence of reduced flow in the carotid arteries in patients with high flow in the graft arm. A tendency toward higher volume flow in both carotid arteries in patients with high volume flow in the graft arm was noted. We found no evidence of shunt-induced cerebral hypoperfusion. Cerebral autoregulation appears to be patent even with high brachial artery shunt volume.
