Transcranial Doppler in Sickle Cell Anemia Adult Patients: Brazilian Experience.

Sickle cell anemia (SCA) may cause a variety of neurological complications, including stroke and headaches. Stroke occurs in up to 9% of children with SCA, and transcranial Doppler (TCD) studies have demonstrated that increased velocities are related to higher stroke risk. Throbbing headache occurs in SCA but its cause, frequency, and relationship to TCD velocities have received little attention. On the other hand, there are few TCD studies in adult patients. Our aims were: 1) to describe the main features of TCD in adult SCA patients, and 2) to investigate if there were correlation between TCD features and presence of headache. TCD was performed in 56 adult SCA patients (≥ 16 years old) and in 56 healthy individuals (HI), matched by age and race. There were 6 patients with a remote history of stroke but none were on chronic transfusion. The SCA group was submitted to a neurological evaluation and specifically asked about the occurrence of headache and its characteristics. The highest flow velocity (maxFV) recorded for each artery was considered the most representative. We analyzed the frequency of FV asymmetry (side-to-side difference > 20%) and focal FV changes. The mean maxFV was significantly higher in patients (117.7 ± 21.6 cm/s) than in HI (72.45 ± 11.48 cm/s) (p<0.005). Only one patient had maxFV higher than 170 cm/s. The frequencies of asymmetry and of focal FV changes were significantly higher in SCA. Forty-one patients (73.2%) reported having headaches. Twenty-eight patients (50%) had severe (= 5 for pain intensity at a 1–10 scale) and frequent headaches (at least once a month). This group of patients presented TCD velocities significantly higher than patients without or with milder headaches (p=0.035). In conclusion, TCD maxFV was significantly higher in adult patients with SCA than HI, however, only one patient was considered at risk of stroke according to TCD criteria described in children. FV asymmetry and focal FV changes may be markers for arterial disease in adult SCA patients, and need to be further confirmed by neuroimaging and clinical follow up studies. The patients with severe headaches presented TCD velocities significantly higher than patients without or with milder headaches, but this finding needs to be confirmed by more and larger studies.