Arterial Blood Pressure and Hyperviscosity in Sickle Cell Disease

Hemoglobin sickle cell disease complications: a clinical study of 179 cases

“…22 Prevalence of high blood pressure was 14% in our young HbSC population; this figure is high compared to SCA patients who have low blood pressure despite a high prevalence of kidney disease. 4,23,24 In recent changes to their guidelines, the American Society of Echocardiography increased the TRJV threshold beyond which pulmonary arterial hypertension is suspected from 2.5 to 2.9 m/s because the lower cut-off value resulted in too many false positive results when rightheart catheterization was performed. 10,25 Our results show that, whatever the threshold chosen, pulmonary arterial hypertension is not a particular concern in HbSC disease as in our study cohort no patient had TRJV above 2.9 m/s and only 4% had values above 2.5 m/s compared to 10% and 30%, respectively, in SCA.…”

Venous sinus thrombosis leading to stroke in a patient with sickle cell disease on hydroxyurea and high hemoglobin levels: Treatment with thrombolysis

“…Hyperviscosity and higher hemoglobin levels in sickle cell patients have been associated with clinical complications such as vasoocclusive crises, acute chest syndrome, AVN of the femoral head and stroke [11][12][13]. (The role of hyperviscosity in SCD has been thoroughly reviewed in Ref.…”

“…(The role of hyperviscosity in SCD has been thoroughly reviewed in Ref. 12). Whole blood viscosity depends on the number of erythrocytes, their deformability, and the concentrations of plasma proteins.…”

“…Thus at a hematocrit of 25% the blood viscosity in sickle patients is almost equal to that of normal blood with a hematocrit of 45%. The viscosity further increases dramatically upon deoxygenation of red cells [12]. Furthermore in SCD, and thalassemia, patients acute increase in hemoglobin levels after transfusions have also been associated with severe complications including hypertension, heart failure, seizures, confused mental status, and cerebral hemorrhage.…”

“…Furthermore in SCD, and thalassemia, patients acute increase in hemoglobin levels after transfusions have also been associated with severe complications including hypertension, heart failure, seizures, confused mental status, and cerebral hemorrhage. This syndrome can be explained by increases in viscosity leading to essentially stationary blood flow despite elevated blood pressure [12]. While treatment with hydroxyurea leads to increased hemoglobin in most patients, this is not associated with hyperviscosity or complications probably because of the effects of hydroxyurea in improving the rheologic and adhesive features of sickle erythrocytes [14][15][16].…”