Rastreamento de crianças com Doença Falciforme pelo Doppler transcraniano em uma coorte de pacientes triados pelo Programa Estadual de Triagem Neonatal do Estado de Minas Gerais (PETN-MG) e acompanhados no Hemocentro de Belo Horizonte/MG - Brasil.

Abstract

Neurologic complications in children with sickle cell anemia (SCA) are frequent. Approximately 11% of children and youths up to 20 years of age are at risk of stroke. Transcranial Doppler ultrasonography (TCD) is an important way of detecting risk of ischemic stroke. The aim of this study is to verify the incidence of stroke and altered TCD in children and determine possible risk factors. Methods: We analyzed a cohort of children selected by the Newborn Screening Program of MG, with SCA, born between March 1998 and December 2005 and followed at the Hemominas Foundation until May 2009. TCD was carried out in a randomized cross-section of 300 children. The examination followed STOP protocol, and used pulsed TCD with a 2 MHz probe. Children with mean blood flow velocity <170 cm/s for the middle cerebral artery, distal internal carotid and anterior cerebral artery were classified as low risk; if velocity was of 170-184 cm/s, lower intermediate risk; if velocity was of 185-199 cm/s, higher intermediate risk; and if of 200 cm/s, high risk. Results: mean age of 6.5 years (2-10y); 150 female.194 children (75.6%) were classified as low risk; 19 (7.4%) as lower intermediate risk; 7 (2.6%) as higher intermediate risk; and 8 (3.1%) as high risk; 11.2% of the examinations were considered inadequate. Those 7 children of high risk, after being submitted to confirmatory examinations, started a regimen of chronic transfusion and one of them of hydroxyurea. Another, considered low risk, had a hemorrhagic stroke (normal brain angiography). 13 children (4.8%) had suffered from ischemic stroke prior to having the TCD. Alterations in TCD or clinical stroke were observed in children with a lower mean age (p=0.002). The accumulated probability of having a stroke before age 10 was of 9.5%; of having stroke+altered TCD (intermediate and high risk) was of 38.4%. There was no difference between children with normal TCD and those with altered TCD+stroke in the anthropometric analysis (comparison between mean Z score at age 3), occurrence of acute splenic sequestration (p=0.13) and acute chest syndrome (p=0.16). Mean hemoglobin concentration was lower in children with altered TCD+stroke (p<0.001); mean white blood cell and reticulocyte counts were higher in children with altered TCD+stroke (p=0.006 and p>0.001, respectively). Upon multivariate analysis, mean reticulocyte count was the only significant variable (p=0.0002). We also observed a progressive increase of velocity in the basilar artery of children with higher velocity in the middle cerebral arteries (R= 0.59); p<0.001): 8 out of 25 children with altered TCD had basilar velocity >130 cm/s; out of the 186 low risk children, only one had basilar velocity >130 cm/s (p<0.001). Conclusions: frequency of clinical stroke was similar to that seen in the literature and that of high risk TCD, lower. The accumulated probabilities of altered TCD are high and require special attention in the following of children with SCD. High reticulocyte count was the most important factor in predicting erebrovascular disease. Basilar artery velocity >130 cm/s is another predictive factor for cerebrovascular disease.