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Transcranial Doppler (TCD) is used to detect children with sickle cell anemia (SCA) who are at risk for stroke, and transfusion programs significantly reduce stroke risk in patients with abnormal TCD. We describe the predictive factors and outcomes of cerebral vasculopathy in the Créteil newborn SCA cohort (n = 217 SS/Sβ0), who were early and yearly screened with TCD since 1992. Magnetic resonance imaging/magnetic resonance angiography was performed every 2 years after age 5 (or earlier in case of abnormal TCD). A transfusion program was recommended to patients with abnormal TCD and/or stenoses, hydroxyurea to symptomatic patients in absence of macrovasculopathy, and stem cell transplantation to those with human leukocyte antigen-genoidentical donor. Mean follow-up was 7.7 years (1609 patient-years). The cumulative risks by age 18 years were 1.9% (95% confidence interval [95% CI] 0.6%-5.9%) for overt stroke, 29.6% (95% CI 22.8%-38%) for abnormal TCD, which reached a plateau at age 9, whereas they were 22.6% (95% CI 15.0%-33.2%) for stenosis and 37.1% (95% CI 26.3%-50.7%) for silent stroke by age 14. Cumulating all events (stroke, abnormal TCD, stenoses, silent strokes), the cerebral risk by age 14 was 49.9% (95% CI 40.5%-59.3%); the independent predictive factors for cerebral risk were baseline reticulocytes count (hazard ratio 1.003/L × 109/L increase, 95% CI 1.000-1.006; P = .04) and lactate dehydrogenase level (hazard ratio 2.78/1 IU/mL increase, 95% CI1.33-5.81; P = .007). Thus, early TCD screening and intensification therapy allowed the reduction of stroke-risk by age 18 from the previously reported 11% to 1.9%. In contrast, the 50% cumulative cerebral risk suggests the need for more preventive intervention.

Stroke is predicted by abnormally high cerebral velocities by transcranial doppler (TCD). This study aimed at defining predictive factors for abnormally high velocities (≥ 2 m/sec) based on the Créteil pediatric sickle cell anemia (SCA) cohort composed of 373 stroke-free SCA children. α genes and β-globin haplotypes were determined. Biologic parameters were obtained at baseline. α-thalassemia was present in 155 of 325 and G6PD deficiency in 36 of 325 evaluated patients. TCD was abnormal in 62 of 373 patients. Multivariate logistic regression analysis showed that G6PD deficiency (odds ratio [OR] = 3.36, 95% confidence interval [CI] 1.10-10.33; P = .034), absence of alpha-thalassemia (OR = 6.45, 95% CI 2.21-18.87; P = .001), hemoglobin (OR per g/dL = 0.63, 95% CI 0.41-0.97; P = .038), and lactate dehydrogenase (LDH) levels (OR per IU/L = 1.001, 95% CI 1.000-1.002; P = .047) were independent risk factors for abnormally high velocities. This study confirms the protective effect of alpha-thalassemia and shows for the first time that G6PD deficiency and hemolysis independently increase the risk of cerebral vasculopathy.

Allogeneic hematopoietic stem-cell transplantation (HSCT) is the only curative treatment for sickle cell disease (SCD); nevertheless, its use has been limited by the risk of transplantation-related mortality (TRM). Between November 1988 and December 2004, 87 consecutive patients with severe SCD ranging from 2 to 22 years of age received transplants in France. Cerebral vasculopathy was the principal indication for transplantation (55 patients). All the patients received grafts from a sibling donor after a myeloablative conditioning regimen (CR). The only change in the CR during the study period was the introduction of antithymocyte globulin (ATG) in March 1992. The rejection rate was 22.6% before the use of ATG but 3% thereafter. With a median follow-up of 6 years (range, 2.0 to 17.9 years), the overall and event-free survival (EFS) rates were 93.1% and 86.1%, respectively. Graft versus host disease (GVHD) was the main cause of TRM. Importantly, cord blood transplant recipients did not develop GVHD. No new ischemic lesions were detected after engraftment, and cerebral velocities were significantly reduced. The outcome improved significantly with time: the EFS rate among the 44 patients receiving transplants after January 2000 was 95.3%. These results indicate that HLA-identical sibling HSCT after myeloablative conditioning with ATG should be considered as a standard of care for SCD children who are at high risk for stroke.

Abstract 263 Early occurrence of dactylitis, severe anemia and leukocytosis have been identified as risk factors for adverse outcome in children with SCA (Miller NEJM 2000), but the impact of acute splenic sequestrations (ASS) on disease severity has not yet been reported. The goal of this study was to define the predictive factors of ASS and to evaluate if this complication was a risk factor for disease severity. Methods. SS patients of the newborn cohort, seen at our SCA Center in Créteil before 3 months of age and older than 2 years at the last visit (n=197), were included in this study. Alpha and beta genotypes, and G6PD activity were determined. Blood parameters were recorded at steady state during the second year of life. ASS was defined as an Hb-decrease of ≥20% associated with a spleen-increase ≥2cm. Vaso-occlusive crises (VOC) requiring hospitalizations and acute chest syndromes (ACS) were recorded. The yearly rates of VOC and ACS were calculated for the entire follow-up and for the period before any intensification (transfusion program, hydroxyurea or SCT). Results. Median follow-up was 7.9 yr (range 2–24), providing 1820 patient-years. Alpha-Thal was present in 70/162 (43.2%); beta-haplotypes, available in 140 patients, were Car/Car in 62 (44.3%), Ben/Ben in 35 (25%), Sen/Sen in 7 (5%), and others in 34 (25.7%). G6PD deficiency was present in 24/171 (14%). At baseline, mean (SD) blood parameters were: Hb: 8g1/dL (1.2); Ht: 24.6% (3.9); MCV: 79.2 fL(8.3); HbF: 15.7% (8.2); LDH: 919 UI/L (369) and reticulocytes: 296 (114); WBC: 14.3 (5.2), neutrophils 5.8 (3.1) × 109/L. Among the 197 SS-patients, 64 (32%) experienced their first ASS at the median age of 2.0 yr (range 0.1–12.9) and 36/64 recurred. ASS occurred before 1 yr of age in 10 (5%) and before 2 yr in 33/197 (17%). Splenectomy was performed in 24 of them at the median age of 5.1 yr (range 2.7–12.9). The KM-estimated cumulative risk of ASS occurrence at age 7 was 32% (95%CI: 25–39%). The Cox-regression analysis showed that gender, G6PD deficiency, beta haplotypes were not risk factors whereas alpha-Thal significantly increased the risk of ASS occurrence (HR: 1.9, 95% CI:1.1-3.3, p=0.021). Among blood parameters, multivariate Cox analysis retained low platelet (HR: 1.4 per 1×107/L decrease; 95%CI:1.1-1.8, p=0.014) and high reticulocyte counts (HR=2.0 per 1×107/L increase; 95%CI:1.6-2.6) as independent significant predictive factors for ASS. Comparison of patients with or without ASS history showed no significant difference in the rate of ACS but significantly higher rates of VOC during the entire follow-up (0.68±0.58 vs 0.47±0.55; p=0.014) and in the number of hospitalizations (1.64±0.83 vs 1.29±0.92; p=0.01) in patients with ASS history. Rates of VOC before intensification were 1.1±0.7 and even 2.2±2.0 in those having experienced ASS before age 1 vs 0.6±0.7 (p=0.001) in those with no ASS history. Conclusion. Results from this study in a newborn cohort show that ASS are more frequent in patients with alpha-Thal and are associated with a higher rate of VOC. Splenectomy is usually recommended in case or recurrent ASS; however, our previous results show that geno-identical SCT can cure 95%SCA children and partly restore splenic function. We suggest that this procedure be proposed to those with available donor before considering total splenectomy. Disclosures: No relevant conflicts of interest to declare.

Background Silent infarcts are associated with impaired cognitive functioning and have been shown to be predictors of stroke (Miller ST J Pediatr 2001). Until now, reported risk factors for silent infarcts were low pain event rate, history of seizures, high leukocyte count and Sen bS haplotype (Kinney TR Pediatrics 1999). Here, we seek to define the prevalence and risk factors of silent infarcts in the Créteil SCA pediatric cohort comprising patients assessed at least yearly by transcranial doppler (TCD) since 1992, and by MRI/MRA. Methods This study retrospectively analyzed data from the Créteil cohort stroke-free SS/Sb0 children (280; 134 F, 146 M), according to institutional review board. Time-averaged mean of maximum velocities higher than 200 cm/sec were considered as abnormal, resulting in initiation of a transfusion program (TP). A switch to hydroxyurea was proposed to patients with normalized velocities (< 170 cm/sec) and normal MRA on TP, although TP was re-initiated in case of abnormal velocities recurrence. Patients with “conditional” velocities (170–199 cm/sec) were assessed by TCD 4 times yearly. Alpha genes and beta-globin haplotypes were determined. Baseline biological parameters (G6PD activity; WBC, PMN, Reticulocytes, Platelets counts; Hemoglobin, Hematocrit, HbF, LDH levels; MCV; SpO2) were obtained a minimum of 3 months away from a transfusion, one month from a painful episode, after 12 months of age, before the first TCD, and always before therapy intensification. Results. Patients were followed for a total of 2139 patient-years. Alpha-Thal was present in 114/254 patients (45%) and 27/241 (11.2%) had G6PD deficiency. Beta genotype, available in 240 patients, was BaBa in 102 (42.5%), BeBe in 54 (22.5%), SeSe in 19 (7.9%) and “other” in 65 (27.1%); TCD was abnormal in 52 of 280 patients (18.6%). MRA showed stenoses in 30 of 226 evaluated patients (13.3%) while MRI demonstrated presence of silent infarcts in 81/280 patients (28.9%). Abnormal TCD (p Conclusion We recently showed that G6PD deficiency, absence of alpha-Thal, and hemolysis are independent significant risk factors for abnormal TCD in stroke-free SCA patients (Bernaudin et al, Blood, 2008, in press). Here, we report that an abnormal TCD is the most significant risk factor for stenoses and, expanding previous studies, we demonstrate that stenoses, low Hb and gender are significant independent risk factors for silent infarcts.

Background Predicting the severity of sickle cell anemia (SCA) is important for providing better informed genetic counseling and for better targeting of intensive therapies. Stroke is the most severe complication in children with SCA and is predicted by abnormally high cerebral velocities by transcranial doppler (TCD). We attempted to define the risk factors associated with high velocities. Methods This study concerned the Créteil pediatric SCA cohort, composed of newborn patients, screened and followed at our Center since birth, and of patients secondarily referred to the Center because of the severity of their disease. Time-averaged mean of maximum velocities (TAMMX) higher than 200 cm/sec were considered as abnormal, resulting in initiation of a transfusion program initiated. Cerebral MRI/MRA was done after the age of 5 years or earlier in case of abnormal TCD. Alpha genes and beta-globin haplotypes were determined. Baseline biological parameters (G6PD activity; WBC, PMN, Reticulocytes, Platelets counts; Hemoglobin, Hematocrit, HbF, LDH levels; MCV; SpO2) were obtained a minimum of 3 months away from a transfusion, one month from a painful episode, after 18 months of age and, before intensive therapy. Results SS children (390; 189 F, 201 M) were annually explored by TCD (n=2286) since 1992, and followed for a total of 1962 patient-years. The follow-up before initiation of intensive therapy was 1032 patient-years. Nineteen patients experienced an overt stroke. TCD was abnormal in 65 of 390 patients (17%). MRI (n=850) was performed in 268 patients, was abnormal in 86 cases and showed silent infarcts in 67 of 249 patients (27%). Silent infarcts were seen in 33% of patients with abnormal TCD. Alpha genes study, available in 336 patients, demonstrated alpha-thalassemia in 158 patients (47%): 31 had a deletion of 2 genes (7.9%) and 127 of 1 gene (32.6%). G6PD deficiency was present in 26 of 228 evaluated patients (11%). Beta-globin haplotypes studied in 316 patients were Car/Car in 125 (40%), Ben/Ben in 76 (24%), Sen/Sen in 30 (9%) and, “other” in 85 (27%). Univariate analysis showed that the risk of abnormally high velocities was not related to sex, beta-globin haplotypes, pain and acute chest syndrom rates, WBC, PMN, platelets counts, HbF level and SpO2 but was significantly associated with the absence of alpha-thalassemia (p< 0.001), G6PD deficiency (p=0.012), low Hb and Ht levels (p< 0.001), high reticulocyte count (p=0.008), high MCV (p=0.004) and high LDH level (p 1200 UI/L [OR=4.5, 95% CI (1.5–13.5)], (p=0.007) were independent risk factors of abnormally high velocities. Conclusion This study confirms that the risk of high velocities in patients with SCA is significantly decreased by the presence of alpha-thalassemia. It shows for the first time that hemolysis is a more significant risk factor than the degree of anemia and that absence of alpha-thalassemia, G6PD deficiency and hemolysis are significant independent risk factors of cerebral vasculopathy in patients with SCA.

About 11% of SS patients will have a first stroke by age 18–20 years. Abnormal high velocities are associated with a high risk of stroke, which can be significantly reduced by a long-term transfusion program. The stroke rate in Californian SCD children has declined since the advent of transcranial doppler (TCD), but there are no reports on the outcome of patients screened from birth by TCD. Since 1992, TCD has been systematically performed from the age of 12–18 months in the Creteil cohort. MRI/MRA was performed annually after the age of 5 years, or earlier in case of abnormal TCD. Patients with abn. high velocities (TAMMX >= 200 cm/s) were offered transfusion regimens for stroke prevention, but hydroxyurea was proposed secondarily to patients who had normal MRA findings and whose velocities normalized (< 170 cm/s). TCD was performed every three months in these patients, and a transfusion program was resumed if the findings were again abnormal. We report the cerebrovascular outcome of patients born after 1988 who were regularly followed in our center and screened by TCD. This cohort consisted of 242 SCD patients (178 SS, 9 Sb0, 41 SC, and 14 Sb+). Mean follow-up was 6.2 y (range 0.1–17.8), representing 1498 patient-years overall and 1139 patient-years in the SS/Sb0 population. Alpha gene deletion was present in 41% of patients (71/175). The beta genotype was available in 165 patients, and was homozygous Bantou (n=56, 34%), Senegal (n=9, 5.5%), Benin (n=35, 21.2%), or "other" (n=65, 39.4%). Four deaths occurred, all involving SS patients, at 1.2 y (enteritis in 1995), 1.8 y (trip to Africa in 2003), 1.9 y (pneumo. meningitis in 1997) and 3.7 y (ACS and curare allergy in 1998). The mortality rate was 0.27 per 100 patient-years overall and 0.35 in SS/Sb0 patients. The Kaplan-Meier (KM) estimate of the risk of abn. velocities (> 200 cm/s) was 15.7% at 5 y and 22.7% at 10 y of age in SS/Sb0 patients. No SC/Sb+ patients had abn. velocities. Strokes occurred in only two SS patients: the first patient had abn. high velocities detected at the age of 1.5 years and had a stroke at the age of 1.6 years, just before the TCD control and initiation of the transfusion program. The second patient had normal left-sided velocities but no available temporal window on the right side after the age of 1.4 y; this patient had a stroke at age 4.4 y. These observations prompted us to begin TP after the first abn. TCD and to perform MRI/MRA when no window was available. The rates of stroke were 0.13 per 100 patient-years overall, and and 0.18 per 100 patients-years in SS/Sb0 patients. The KM estimate of the risk of stroke was 1.02% at 5 y and 18 y of age in SS/Sb0 patients. KM estimates of the risk of ischemic lesions at 5 and 10 y were respectively 6.4% and 17.7% in SS/Sb0 patients with normal TCD and 20.9% and 43.5% in patients with a history of abn. TCD (Log Rank test 0.0035). This single-center study shows that a strategy based on early and regular TCD can efficiently prevent stroke in a newborn screened cohort: the rate of stroke and the KM risk of stroke were far lower than recently reported (Quinn CT Blood 2004). However, the risk of ischemic lesions remained high particularly in patients with a history of abn. velocities. Abn. TCD velocities identify a high-risk group who may qualify for matched related donor stem cell transplantation.

Hematopoietic cell transplantation (HCT) is the only potentially curative treatment for sickle cell disease (SCD). The probability of event-free survival is currently between 85 and 90% after matched sibling-donor HCT. This intensive treatment conducts to a major change for patients and families. The purpose of the present study was to determine the psychological impact on individuals and their families of this recovery process after HCT. The hypothesis was that the recovery is a process with different aspects (medical, psychological, individual, familial and cultural) which could be discordant. This study was supported by the Etablissement Français des Greffes (EFG) and conducted by child and adolescent psychiatrists, psychologists and a medical anthropologist. The assessment consisted in two semi-structured interviews adressed to the patients and their families for studying their illness narratives and questionnaires for quality of life, post-traumatic stress disorder (PTSD), depression and anxiety. 28 patients (17 males, 11 females) with SCD treated in France by HCT (22 by bone marrow and 6 by cord blood transplantation) and their families were evaluated at least one year (median 5 years, range, 1–14 years) after HCT at the median age of 14 years (range, 4–24 years). Among these 28 patients, 7 had prior history of severe vasculopathy and 6 of stroke before the HCT. At evaluation, 27 patients were free from SCD symptoms (but 3 had moderate chronic GVHD), 1 had graft rejection. 9 patients (4 males, 5 females) (median age 16 years, range 7–23 years) presented psychiatric symptoms as inhibition, depression, hypomaniac symptoms, anxiety, stutter. A psychiatric care was indicated for these 9 subjects. No diagnosis of current PTSD was found. Psychological distress was reported by parents. 21 patients considered themselves as cured, 4 of them in an incomplete way (none with stroke before the HCT, 3 with moderate chronic GVHD), and 3 not cured at all (none with stroke before the HCT, 1 with graft rejection). The study of the narratives illustrated the major individual, familial and cultural changes after the HCT. The recovery needed complex adjustments. Patients had to cope with new potentialities and requirements: school and relationships with peers, identity issues (disease transmission, infertility) and family changes. This study underlies the importance of psychological interventions for improving the outcome of patients with SCD treated by HCT and their families.

Abnormal TCD defined as high mean maximum velocities > 200 cm/sec are highly predictive of stroke risk and justify long term transfusion program. Outcome and risk factors of conditional TCD defined as velocities 170–200 cm/sec remains to be described. Patients and methods Since 1992, 371 pediatric SCD patients (303 SS, 44 SC, 18 Sß+, 6 Sß0) were systematically explored once a year by TCD. The newborn screened cohort (n=174) had the first TCD exploration between 12 and 18 months of age. TCD was performed with a real-time imaging unit, using a 2 MHz sector transducer with color Doppler capabilities. Biological data were assessed at baseline, after the age of 1.5 years and remotely of transfusion or VOC. We report the characteristics and the outcome in patients (n=43) with an history of conditional TCD defined by mean maximum velocities ranging between 170 and 200 cm/s in the ACM, the ACA or the ICA. Results: The mean follow-up of TCD monitoring was 5,5 years (0 – 11,8 y). All patients with an history of conditional doppler were SS/Sb0 (n=43). Mean (SD) age of patients at the time of their first conditional TCD was 4.3 years (2.2) whereas in our series the mean age at abnormal TCD (> 200 cm/sec) occurrence was 6.6 years (3.2). Comparison of basal parameters showed highly significant differences between patients with conditional TCD and those with normal TCD: Hb 7g4 vs 8g5 (p 80 (p=0.04). MRI/MRA was performed in 31/43 patients and showed ischemic lesions in 5 of them at the mean (SD) age of 7.1 y (1.8) (range 4.5–8.9): no significant difference was observed in the occurrence of lesions between the 2 groups. Conclusions This study confirms the importance of age as predictive factor of conditional to abnormal TCD conversion with a risk of 64% when first conditional TCD occured before the age of 3 years. TCD has to be frequently controled during the 5 first years of life.

Treatment intensifications in SCD with HU, TP or SCT are applied in order to reduce SCD related complications but their comparative effects have still to be described. We report our experience concerning the annual check-up performed in SCD pediatric patients. Patients and Methods: Among our cohort of 397 SS/Sb0 pediatric SCD patients, 157 of them were intensified with HU (n= 86), TP (n=104) or SCT (n=36) and some of them received successively HU, TP and SCT. HU was proposed to patients > 3 years of age and having experienced more than 3 VOC/ACS/year or < 7g/dl severe anemia. TP defined as > 4 months program was applied in patients with cerebral vasculopathy defined by an history of stroke or abnormal TCD (> 200 cm/sec). TP was also proposed in patients with HU-failure and in patients with frequent VOC, less than 3 years old. SCT was proposed in patients with an indication of treatment intensification and an available HLA identical sibling donor. Annual check-up were performed in our day-care unit. We analysed 1261 check-ups performed and recorded since 1992 in 341 SS/Sb0 patients (sex: 164 F, 177 M). Median age was 8.8 ± 5.1 years. Mean number of annual check-ups per patient was 3.7 ± 2.8 (range 1 to 13): 816 were performed in non intensified patients, 196 in HU, 123 in TP and 126 in transplanted patients. Categories of age were distinguished: < 2 y of age (n=110), 2–5y (n=244), 5–10y (n=415), 10–15y (n=317) and 15–20y (n=175). Results: Respective follow-up were 4.4 y ± 3.3 in HU, 2.6 y ± 2.6 inTP and 5.8 y ± 4.7 in SCT patients. Comparison with non intensified patients showed that weight was significantly higher in SCT patients > 15 y of age (p=0.001), spleen size was significantly higher in (2–5y) young patients treated with HU (p=0.005) or TP (0.001) and in 5–10 y old patients on HU (p=0.046) but no difference was observed after the age of 10 y. O2 saturation was significantly improved after SCT (p Conclusion : Treatment intensifications (TP, HU, SC) reduced the decrease of weight observed with aging in SCD patients and significantly reduced anemia using different mechanisms. SCT was the most effective to correct anemia, supress hemolysis and decrease leucocytosis. Intensif. n Follow-up HbF% Eryht Hb MCV Retic mean (SD) No 816 11.4 (9.2) 3.1 (0.9) 8.1 (1.2) 81.4 (8.9) 268.9 (105.2) HU 196 4.4 y. (3.3) 13.9 (7.0) 2.7 (0.6) 8.5 (1.2) 97.7 (13.7) 188 (83.8) TP 126 2.6 y.(2.7) 3.3 (3.1) 3.1 (0.6) 9.1 (1.4) 86.8 (4.8) 258.2 (126.0) SCT 123 5.8 y.(4.7) 4.6 (6.4) 4.3 (0.9) 11.4 (1.6) 81.5 (8.9) 89.4 (63.4) Intensif. n Tot Bili Conj Bili LDH Ferritin Leucocytes Platelets No 816 49.8 (34.4) 5.7 (3.4) 1016 (312) 192 (322) 13.2 (9.9) 385 (124) HU 196 47.5 (34.4) 5.0 (2.2) 943 (264) 399 (582) 9.7 (3.8) 352 (133) TP 126 58.8 (39.6) 5.6 (2.2) 973 (377) 2238 (6310) 13.1 (4.7) 365 (128) SCT 123 15.6 (13.9) 2.8 (4.2) 493 (200) 1099 (1386) 6.8 (3.3) 295 (109)

Frequent vaso-occlusive crisis (VOC) and acute chest syndromes (ACS) cause high morbidity and early death and justify intensification of treatment. We report the comparative effects of Hydroxyurea (HU), Transfusion program (TP) or Stem Cell Transplant (SCT) on VOC and/or ACS occurrence in 76 SS/Sb0 patients. Patients and Methods: This study only concerned the patients always followed and hospitalized in our pediatric center in Creteil, from 1979 to June 2004: among this cohort of 256 SS/Sb0 patients, 76 received a treatment intensification justified by a high frequency of hospitalizations (3 3 VOC/y or 2 ACS/y). For this indication, HU was proposed since 1992 in 53 patients older than 3 years of age without abnormal cerebral velocities on Trans-cranial Doppler (TCD), TP in 42 patients younger than 3 years of age or having abnormal TCD (> 200 cm/sec) or HU failure in VOC/ACS frequency reducing, and SCT was performed in 15 patients with an available HLA identical sibling donor (14/15 successful). Several patients successively received different treatments: HU-TP (n=19), HU-TP-SCT (n=5), TP-SCT (n=6) and one patient who rejected the graft was treated with HU. We compared (student t-test) the causes, the frequency and duration of hospitalizations occurred during the year preceding the treatment intensification with those observed after the intensification program. For transplanted patients, we distinguishly considered the events having occurred during the first year post-transplant and those having occurred after. Results: Mean (± SD) follow-up before intensification was 8.1 years (± 4.5) with 2.3 hospitalizations/year (± 2.2) occured since birth. During the year preceding the treatment intensification, an higher number of hospitalizations (3.9 ± 2.1) occurred with 24.3 days of hosp (± 19.1) and the mean number of VOC was 2.3 (± 2) and ACS was 0.5 (± 0.8). After intensification, number of hospitalizations and VOC and ACS, duration of hosp significantly (p Conclusion: Intensive treatments were significantly efficient to decrease the number and the duration of hospitalizations and the number of VOC and ACS. TP maintening HbS level < 40% was significantly more efficient than HU to prevent VOC (p

Abnormal high velocities are predictive of high stroke risk which can be significantly reduced by transfusion program (Adams and al). They are related to stenosis, severe anemia or tissue hypoxia. We hypothesized that high velocities observed in patients with normal MRA and normalized on transfusion program (TP), were anemia related and could be safely decreased with hydroxyurea (HU)-therapy. Patients and Methods: since 1992, 291 pediatric SCD patients (235 SS, 40 SC, 3 Sb0, 11 Sb+) were systematically explored once a year by TCD. The newborn screened cohort (n=149) had the first TCD exploration between 12 and 18 months age. TCD was performed with a real-time imaging unit, using a 2 MHz sector transducer with color Doppler capabilities. When abnormal high velocities (defined as mean maximum velocities > 200 cm/sec in MCA, ACA or ICA) were observed, TCD was controlled and the patient treated with TP and cerebral imaging (MRI/MRA) was performed within 3 months. In patients with severe stenosis, TP was pursued or transplantation performed. In patients with normal MRA and transfusion-normalized velocities, a progressive switch towards HU therapy was applied and TCD controlled once a trimester. Results: among the stroke-free patients (n=281), abn. high velocities were detected in 25 patients (all SS:11% of incidence in SS patients). In the newborn screened population, velocities became abnormal in 10 patients at the median age of 5.7 years (range 1.4 – 12.5 y). The first MRI/MRA (n=24/25) performed in the 3 months following the detection of high velocities showed MRI/silent infarcts in 9/24 (38%): only 1/11 among the newborn screened cohort had silent infarcts in contrast with 8/13 older patients secondary referred in our center. MRA detected severe vascular abnormalities in 10 and mild in 3 patients. Mean velocities (2.69 m/sec) were significantly higher (p=0.002) in the 7 patients with abn. MRI and MRA than in the 10 patients (2.11m/sec) who had normal MRI and MRA. One stroke occurred in a very young 1.6 y old girl just before the second TCD evaluation (first abn. TCD had been observed at 1.5 y) and before the beginning of the TP. Long-term outcome: no stroke was observed following the initiation of the TP. With a median follow-up of 4.4 years (0.5 to 11.4 y.), velocities remained abnormal in 11/25 patients: 7 of them had abnormal MRA and among the 4 patients with normal MRA at first exploration MRA became abnormal in 2 cases showing that abnormal TCD can precede the occurrence of cerebral vasculopathy. TP was maintained in 7 patients and safely stopped in 4 patients transplanted with genoidentical donor. Velocities normalization (defined as < 170 cm/sec) was observed in 13/25 patients in a median delay of 0.75 years (0.25 – 2.3 years). TP was stopped in 10 patients with normal MRA and therapy was switched towards HU in 7 patients with abstention in 3. However, abnormal TCD relapsed in 4 patients who were again placed on TP. Conclusion: abnormal high velocities concerned 11% of SS patients and were predictive of MRA and MRI lesions occurrence. TP was efficient to prevent the stroke risk and normalized velocities in about 50% of patients but relapses were observed in 4/7 patients following TP stop and HU switch. Only few patients with high velocities history did not develop cerebral vasculopathy. Also, early TCD allows a selection of very high risk patients justifying the research of suitable donors.