FMD was impaired in SCD subjects but partially ameliorated in transfused SCD subjects.

Chronically transfused SCD patients were studied prior to and following a single transfusion and there was no acute change in rSO 2 or perfusion.

In contrast, rSO 2 was 12 saturation points lower in non-transfused SCD patients, but normal in the transfused SCD patients.

Laser Doppler estimates of resting perfusion were 76% higher in non-transfused and 110% higher in transfused SCD patients, compared to control subjects.