Characteristics of the cohort and evolution of clinical and biological parameters under the ET program
| . | Patients on the ET program . | Patients on the ET program who received HU therapy . | ||
|---|---|---|---|---|
| N (%) . | Median (IQR) . | N (%) . | Median (IQR) . | |
| No. of patients | 48 | 40 | ||
| Age (y) | 11.67 (8.13-16.64) | 9.48 (6.63-13.54)†† | ||
| Duration of the ET program (y) | 4.81 (1.96-8.99) (ns) | 3.72 (1.84-6.17) (ns) | ||
| Characteristics of CV before the start of the ET program | ||||
| Abnormal TCD and normal cerebral MRA without stroke | 2 (4.2) | 10 (25) | ||
| Stenosis of intracranial arteries on MRA without stroke | 25 (52) | 16 (40) | ||
| Stenosis of cervical arteries on MRA without stroke | 7 (14.6) | 7 (17.5) | ||
| Initial stroke | 14 (29.2) | 7 (17.5) | ||
| Evolution of CV for patients without initial stroke (primary prevention) | ||||
| Improvement | 11 (32) | 6 (18) | ||
| Stagnation | 22 (65) | 23 (70) | ||
| Worsening | 1 (3) | 4 (12) | ||
| Evolution of CV for patients with history of stroke (secondary prevention) | ||||
| Improvement | 1 (7) | 0 (0) | ||
| Stagnation | 10 (72) | 5 (71) | ||
| Worsening | 3 (21) | 2 (29) | ||
| Hemoglobin level (g/dL) | 9.1 (8.7-9.5) | 8.6 (8.4-9.2) (ns) | ||
| Median hemoglobin S (%) | ||||
| Before the ET session | 35.3 (30.4-41.2) | 35 (29-38.4) | ||
| After the ET session | 13 (11.7-15.5) | 14 (11.8-16) | ||
| Leukocyte count (109/L) | ||||
| Before ET program | 12.03 (10.09-14.47)** | 12.31 (10.85-15.10)*** | ||
| During ET program | 11.36 (9.32-12.38) | 9.46 (7.24-11.42)† | ||
| Neutrophil count (109/L) | ||||
| Before ET program | 4.98 (3.69-6.52) (ns) | 5.40 (4.00-7.44)** | ||
| During ET program | 6.19 (4.66-7.71) | 4.86 (361-6.94)†† | ||
| Monocyte count (109/L) | ||||
| Before ET program | 10.8 (5.77-1.43) (ns) | 1.10 (7.66-1.61)* | ||
| During ET program | 1.24 (8.94-1.59) | 9.25 (6.74-1.12)††† | ||
| Lymphocyte count (109/L) | ||||
| Before ET program | 5.16 (4.01-8.21)*** | 5.19 (4.18-5.94)** | ||
| During ET program | 2.96 (2.12-7.51) | 2.71 (2.19-3.58)† | ||
| Platelet count (109/L) | ||||
| Before ET program | 363.0 (312.5-469.5) (ns) | 426.0 (325.2-506.0) (ns) | ||
| During ET program | 397.5 (281.2-483.2) | 361.0 (325.0-503.0) | ||
| Lactate dehydrogenase level (U/L) | ||||
| Before ET program | 950 (590-1209)*** | 1081 (625-1423)*** | ||
| During ET program | 531 (400-718) | 519 (408-612) | ||
| Bilirubin (indirect) (μmol/L) | ||||
| Before ET program | 37 (26-52) (ns) | 41 (33-48) (ns) | ||
| During ET program | 32 (21-52) | 35 (23-55) | ||
| Reticulocyte count (109/L) | ||||
| Before ET program | 313 (236-34 1)* | 312 (232-415) (ns) | ||
| During ET program | 337 (262-458) | 286 (221-376) | ||
| . | Patients on the ET program . | Patients on the ET program who received HU therapy . | ||
|---|---|---|---|---|
| N (%) . | Median (IQR) . | N (%) . | Median (IQR) . | |
| No. of patients | 48 | 40 | ||
| Age (y) | 11.67 (8.13-16.64) | 9.48 (6.63-13.54)†† | ||
| Duration of the ET program (y) | 4.81 (1.96-8.99) (ns) | 3.72 (1.84-6.17) (ns) | ||
| Characteristics of CV before the start of the ET program | ||||
| Abnormal TCD and normal cerebral MRA without stroke | 2 (4.2) | 10 (25) | ||
| Stenosis of intracranial arteries on MRA without stroke | 25 (52) | 16 (40) | ||
| Stenosis of cervical arteries on MRA without stroke | 7 (14.6) | 7 (17.5) | ||
| Initial stroke | 14 (29.2) | 7 (17.5) | ||
| Evolution of CV for patients without initial stroke (primary prevention) | ||||
| Improvement | 11 (32) | 6 (18) | ||
| Stagnation | 22 (65) | 23 (70) | ||
| Worsening | 1 (3) | 4 (12) | ||
| Evolution of CV for patients with history of stroke (secondary prevention) | ||||
| Improvement | 1 (7) | 0 (0) | ||
| Stagnation | 10 (72) | 5 (71) | ||
| Worsening | 3 (21) | 2 (29) | ||
| Hemoglobin level (g/dL) | 9.1 (8.7-9.5) | 8.6 (8.4-9.2) (ns) | ||
| Median hemoglobin S (%) | ||||
| Before the ET session | 35.3 (30.4-41.2) | 35 (29-38.4) | ||
| After the ET session | 13 (11.7-15.5) | 14 (11.8-16) | ||
| Leukocyte count (109/L) | ||||
| Before ET program | 12.03 (10.09-14.47)** | 12.31 (10.85-15.10)*** | ||
| During ET program | 11.36 (9.32-12.38) | 9.46 (7.24-11.42)† | ||
| Neutrophil count (109/L) | ||||
| Before ET program | 4.98 (3.69-6.52) (ns) | 5.40 (4.00-7.44)** | ||
| During ET program | 6.19 (4.66-7.71) | 4.86 (361-6.94)†† | ||
| Monocyte count (109/L) | ||||
| Before ET program | 10.8 (5.77-1.43) (ns) | 1.10 (7.66-1.61)* | ||
| During ET program | 1.24 (8.94-1.59) | 9.25 (6.74-1.12)††† | ||
| Lymphocyte count (109/L) | ||||
| Before ET program | 5.16 (4.01-8.21)*** | 5.19 (4.18-5.94)** | ||
| During ET program | 2.96 (2.12-7.51) | 2.71 (2.19-3.58)† | ||
| Platelet count (109/L) | ||||
| Before ET program | 363.0 (312.5-469.5) (ns) | 426.0 (325.2-506.0) (ns) | ||
| During ET program | 397.5 (281.2-483.2) | 361.0 (325.0-503.0) | ||
| Lactate dehydrogenase level (U/L) | ||||
| Before ET program | 950 (590-1209)*** | 1081 (625-1423)*** | ||
| During ET program | 531 (400-718) | 519 (408-612) | ||
| Bilirubin (indirect) (μmol/L) | ||||
| Before ET program | 37 (26-52) (ns) | 41 (33-48) (ns) | ||
| During ET program | 32 (21-52) | 35 (23-55) | ||
| Reticulocyte count (109/L) | ||||
| Before ET program | 313 (236-34 1)* | 312 (232-415) (ns) | ||
| During ET program | 337 (262-458) | 286 (221-376) | ||
Improvement of CV: a decrease in the percentage of arterial stenosis in at least 1 cerebral artery on cerebral magnetic resonance angiography (MRA) and/or a decrease in the cerebral blood flow velocities in at least 1 cerebral artery (below 200 cm/s) on transcranial Doppler (TCD) ultrasound. Stabilization of CV: persistence of stable arterial stenosis on cerebral MRA and/or persistence of cerebral blood flow velocities upon 200 cm/s on TCD. Worsening of CV: an increase in the percentage of arterial stenosis in at least 1 cerebral artery and/or the appearance of a new arterial stenosis on cerebral MRA and/or the appearance of new abnormal cerebral blood flow velocities in at least 1 cerebral artery (200 cm/s) on TCD and/or the occurrence of 1 or several new strokes. The results are presented as medians (interquartile range). Statistical comparisons within biological parameters before and during the ET program for the same patients was determined using a nonparametric paired t test (Wilcoxon rank test) and expressed as ns(P > .05), *(P < .05), **(P < .01), ***(P < .001). Statistical comparison within biological parameters from patients on the ET program without hydroxyurea (HU treatment) compared to patients on both the ET program and on HU therapy was determined using a nonparametric unpaired t test (Mann–Whitney t test) and expressed as ns(P > .05), †(P < .05), ††(P < .01), †††(P < .001).