Blood pressure variations in Subjects with different Haemoglobin Genotypes

Previous studies on low blood pressure in patients with homozygous sickle cell disease (SCD)
have sought various hypotheses on the mechanism of their low blood pressure. However,
these studies have not compared the role of the single inheritance of the s-gene in the
variations in blood pressures as well as relating the blood pressures in different haemoglobin
(HB) genotypes to each other. Blood pressures in 20 steady and crisis states SCD patients
respectively with 40 apparently healthy heterozygous HB AS and HB AA genotype (age and
sex –matched). They were aged between 20 and 40 years. Results showed a significantly
(p<0.05) lower blood pressure (systolic and diastolic) in SCD in stable (but not in crisis) state
compared with the normal controls. The systolic blood pressures in control (HB AA) and SCD
patients were 125.33 ± 2.25 versus 115.25 ± 2.9 (stable state); 125.33 ± 2.25 versus 124.83 ±
2.88 (crisis state, p>0.05), 82.33 ± 1.2 versus 72.25 ± 1.81 (stable state, p<0.05) and 82.33 ±
1.2 versus 99.5 ± 5.81 (crisis state, p<0.05). Also, HB AS subjects exhibited significantly
higher diastolic pressure than HB AA and HB SS subjects during crisis. In conclusion, this
study shows that systolic and diastolic blood pressures are lower in SCA patients in stable state
(compared with control, HB AA subjects) but are relatively higher during crisis while diastolic
blood pressure is significantly higher in HB AS than HB AA and HB SS subjects in crisis.
Further work needs to be done to determine the mechanism for this variation.