Background and purpose: Sickle cell disease is associated with cerebral hyperemia, which is therapeutically reduced by transfusion; however, the process of transfusion-induced cerebral perfusion changes has heretofore not been observed.
Methods: We document the acute changes of intracranial arterial velocity in 10 patients (7 with strokes, 3 without) undergoing transfusion therapy using transcranial Doppler ultrasonography. Middle cerebral artery velocities were bilaterally measured every 30 minutes for the duration of transfusion (4 to 5 hours). Regional cerebral blood flow was quantified in 5 of these patients before the transfusion and 24 hours later by the 133Xe technique.
Results: Velocities in stroke-associated vessels (64.33 +/- 18.65 cm/s; n = 6) were significantly lower than in uninfarcted territories (99.54 +/- 27.39 cm/s; n = 13), and both types of vessels showed a robust reduction of blood flow velocities during transfusion. The rates of reduction were not significantly different as a function of prior stroke but did correlate with pretransfusion velocities and with the rise in hematocrit (multiple r = .887, P < .001). These reductions occurred rapidly within the first 3 hours of transfusion. Velocities attained at the end of transfusion were maintained in the hour after transfusion and the next day.
Conclusions: We conclude that transfusion induces rapid changes in cerebral hemodynamics that are related to pretransfusion velocities and a rise in hematocrit. Transcranial Doppler provides a safe, simple, and noninvasive technique of monitoring these changes and may provide a means of making therapeutic decisions regarding transfusion therapy in patients with sickle cell anemia.