2. Objectives
• Brief overview of SCU programme in Jamaica
• SCD pathophysiology /Phenotypes
• Blood Pressure & Flow
• ANS activity in SCD
• Factors affecting longitudinal changes in GFR
Improving Lives through
Prof Marvin Reid Research, Education & 2
Clinical Care
3. SCU - Mission Statement
The Sickle Cell Unit is a research
institution which seeks to
improve the lives of individuals
with sickle haemoglobinopathies
through rigorous Biomedical
Research, Clinical Care,
Education and Counseling.
Prof. Marvin Reid 3
4. Sickle Cell Unit
SCU-The only comprehensive clinic for the care of persons
with SCD
Prof. Marvin Reid 4
8. SCD Survival in JAMAICA
53 years 58 years
Prof. Marvin Reid 8
9. ARE THERE SCA PHENOTYPES?
Improving Lives through
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Clinical Care
10. Phenotypes in
SCD
• Alexander et al
2004 BJH
– LU Phenotype
=group2
– Painful crises
phenotype
=group 1
11. Gladwin –Haemolytic Phenotype
• Haemolysis rate within individual stable over time
bur differ between individuals
• Haemolysis rate composite measure retic count
LDH AST and total bili
Nouraie et al 2012
17. Viscosity in SCD
• Viscosity affected by :
– HbS polymerization.
– Mediated by reduce RBC deformability.
– Increased adherence of RBC to endothelium [Belcher,
2000].
• Viscosity and haematocrit (Hct)
– Increased Hct improves oxygen delivery, but increases
viscosity.
– Too much Hct → hyper-viscous state →Strokes
– Resultant vaso-occlusion and possible vascular injury.
18. ODI in SS
High Shear
Alexy et al Transfusion 2006
AA blood
AA High Shear
SS
Low Shear
Haematocrit
20. BP in SCD
• BP lower in HbSS compared with HbAA
• In Jamaica BP related to weight
• In CSSCD – Bp correlated with age, BMI and
increased mortality and stroke
23. ANS in Jamaicans with SCD
• Recruited 15 frequent pain crises HbSS, 20
with infrequent pain crises and 24 HbAA
• Holter overnight and tracing analyzed
27. ANS dysfunction in SCD
• Decreased parasympathetic activity and
sympathetic activity predominance in steady-
state conditions.
• ANS CVA & CVS events & Pain
(DM/fibromyalgia)
• In our study no association between
inflammation & ANS activity
• May be related to Hypoxic Stress
28. RENAL & BP IN SCD
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Prof Marvin Reid Research, Education & 28
Clinical Care
29. SCD and Renal function in Jamaica
Pearsons with SCA in the fourth decade of life- there is
6% prevalence of CKD Stage 3 and above and just over
65% of them have albuminuria.
This same cohort has been shown to have a prevalence
of albuminuria of 26% determined 15 years ago, and
42% at determination 5 years ago
10% prevalence of hyperfiltration (defined as measured
GFR >130 mls/min/1.73 m2 in females; and GFR > 140
mls/min/1.73 m2 in males)
We measured GFR in 41 HbSS subjects to assess factors
associated with change in GFR over time
Monika R. Asnani 29
30. Anthropometric characteristics
Variables 1996 2012
Mean SD Mean SD
Age yrs * 21.1 1.2 34.8 2.1
Weight kg * 53.7 6.7 60.0 9.4
Height cm 168.4 8.3 169.5 8.7
BMI kg/m2 * 18.8 2.2 20.9 3.4
31. Haematology & Alb-Creat ratio
Variables 1996 2012
Mean SD Mean SD
Hb g/dl 7.5 1.1 7.3 1.6
Wbc x 109/L 11.6 3.6 10.9 4
Platelets x 1012/L 443 167.8 368.5 136.5
Alb:creat ratio
mg/mmol * 10 25 38.1 136.4
32. Changes in BP in JSCCS1
SBP DBP
*p<0.008
58 61
104 111
34. Predictors of change of GFR over
time adjusting for age and gender
• Weight, BMI, & Alpha thal trait, DBP, WBC
and platelets were not significant
predictors of change in GFR
Predictors Coefficient P value
Haemoglobin 8.8 (3.03) <0.004
Albumin:creat ratio -0.11 (0.04) <0.0001
Serum creatinine -0.15(0.04) <0.0001
SBP -0.96(0.3) <0.002
Pulse pressure -1.05(0.33) <0.002
35. Summary
• The determinants of BP in SCD are anaemia,
rate of haemolysis, anthropometry, ANS
response and Renal function.
• Pain & inflammation associated with ANS
balance
• Elevated BP are associated with Strokes &
CVS
• Decrease in GFR over time is associated with
increased SBP & Albumin creatinine ratio
Editor's Notes
Abs of gaus rel may be due to markdly lowrd Hct – no opt reachd. As depicted by hct/wbv, rheol adv conferred by reduced hct results in lower delivery.
