SCD-Ery.babawith Luhanga and Neil
Transcript of SCD-Ery.babawith Luhanga and Neil
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Paediatric Red Blood CellExchange
IntroductionBaba Inusa
Adult PerspectiveNeil Westerdale
Paediatric and adolescentsLuhanga Musumadi
24th September, 2008
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Indications for Transfusion in
Sickle Cell Disease
2. sickling by lowering Hb S conc.
Prevention of recurrent stroke or
first clinical stroke (abnormal TCD)
Chronic debilitating painful crises
Chronic lung disease with arterial
hypoxaemia
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Complications of Long-term
Transfusion
Transfusional Iron Overload- Delayed growth and sexual maturation
due to endocrine disturbances
- Diabetes mellitus
- Cirrhosis
- Cardiac arrhythmias and heart failure- Death >15-20 yr. of chronic transfusion
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Complications of Transfusion
AlloimmunizationTransfusion-transmitted Infections
Transfusional Iron Overload
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Risk of Recurrent Stroke
If presented within 24 hours of symptomonset, patients who received simpletransfusion had a five times greater risk ofrecurrent stroke when compared tochildren who received exchangetransfusion therapy (95% CI 1.3, 18.6).
No difference in odds of recurrent strokewas found for any type of treatment after24 hours of symptoms.
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Multivariate analysis
Risk of recurrent stroke was 8times higher for patientsreceiving simple transfusion
within 24 hours of symptomsand in the absence of anantecedent medical event (95%CI 1.6, 38.8).
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Time from first stroke to second stroke (years after stroke)
2520151050
C u m
u l a t i v e S t r o k e - F r e e I n t e r v a l
1.0
.8
.6
.4
.2
0.0
Type of Transfusioin
exchange transfusion
exchange transfusion
-censored
simple transfusion
simple transfusion-censored
Risk of Recurrent Stroke(n= 81)
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TransfusionPre – Post –
HAEMATOCRIT (%)
B L O O D V I S C
O S I T Y
( c P )
2
3
10 20 30 40 50
4
5
6
7
Pathophysiology
Jan et al , Transfusion,1982, 22(1):19
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8 8.5 9 9.5 10 10.5 11 11.5
90
80
100
110
120
130
140
150
Hb [g/dL]
C B F [ m L / 1 0 0
g / m i n ]
5 10 15 20 25 30 35 40 45 50 5580
90
100
110
120
130
140
150
C B F [ m L / 1
0 0 g / m i n ]
HbS [%]
Why would exchange transfusion be better thansimple transfusions for decreased risk of strokes?
Hurlet-Jensen et al , Stroke, 1982, 25(8):1690
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Reduce or prevent iron accumulation
while preventing
recurrent stroke in patients with sickle
cell
disease and stroke
ERYTHROCYTAPHAERESIS
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Rationale for Erythrocytaphaeresis
in Reducing Iron Overload
With exchange transfusion, RBCs from patients
are removed while donor RBCs are being given,resulting in fewer RBCs to contribute iron to the
body in comparison with simple transfusion.
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Goals
x Removal of patient’s RBCs:
x Exchange patient’s abnormal RBCs
with normal RBCs:
Erythrocytaphaeresis
- Reduction of blood viscosity in polycythemia
- Reduction of excessive iron in non-anemic
hemochromatosis
- Hereditary or acquired RBC disorders
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Erythrocytaphaeresis in SCD
As a treatment or prevention of
acute complications:q Acute chest syndromeq Strokeq Pre-op (when Hb > 10 g/dl)
As a long-term transfusion therapy
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Long-Term Erythrocytaphaeresis
Sickle Cell Dis with Stroke
< first 3 yr > 3 yr
Pre-Ex Hb S < 30% < 50%*End Hb S (%) 12 - 15 20 - 25
End Hct (%) 27 - 36 27 - 36
• Patient must be clinically and neurologically
stable before raising the target Hb S to <50%
from <30%.
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Acute Erythrocytaphaeresis
AdvantagesxRapid in Hct level without
volume overloadx Rapid Hb S level without
substantially the Hct level
x rate of transfusional iron loading
x Duration of procedure shorter
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Long-term
Erythrocytaphaeresis in SCDAdvantages
Reduces the transfusional iron accumulation- Delays onset of transfusional iron-induced
organ damage
- Delays initiation of iron chelation therapy
- Prevents the need for iron chelation therapy
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Disadvantages
x Problem with venous accessx Increased blood usage x Increased no. of donor exposure
x Increased cost for the proc. (?)
x Universally not available
ERYTHROCYTAPHAERESIS