Cerebrovascular reserve capacity is impaired in patients with sickle cell disease

• Published in: Blood 2009-10, Vol.114 (16), p.3473-3478
• Main Authors: Nur, Erfan, Kim, Yu-Sok, Truijen, Jasper, van Beers, Eduard J., Davis, Shyrin C.A.T., Brandjes, Dees P., Biemond, Bart J., van Lieshout, Johannes J.
• Format: Article
• Language: English
• Subjects: Adult; Anemia, Sickle Cell - blood; Anemia, Sickle Cell - complications; Anemia, Sickle Cell - epidemiology; Anemia, Sickle Cell - physiopathology; Anemias. Hemoglobinopathies; Biological and medical sciences; Blood Flow Velocity; Brain Ischemia - blood; Brain Ischemia - epidemiology; Brain Ischemia - etiology; Brain Ischemia - physiopathology; Carbon Dioxide - blood; Cerebrovascular Circulation; Diseases of red blood cells; Female; Hematologic and hematopoietic diseases; Hemoglobins - analysis; Humans; Incidence; Male; Medical sciences; Nitric Oxide - blood; Oxygen - blood; Oxyhemoglobins - analysis; Risk Factors; Stroke - blood; Stroke - epidemiology; Stroke - etiology; Stroke - physiopathology
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2009-05-223859

Sickle cell disease (SCD) is associated with a high incidence of ischemic stroke. SCD is characterized by hemolytic anemia, resulting in reduced nitric oxide-bioavailability, and by impaired cerebrovascular hemodynamics. Cerebrovascular CO2 responsiveness is nitric oxide dependent and has been related to an increased stroke risk in microvascular diseases. We questioned whether cerebrovascular CO2 responsiveness is impaired in SCD and related to hemolytic anemia. Transcranial Doppler-determined mean cerebral blood flow velocity (Vmean), near-infrared spectroscopy-determined cerebral oxygenation, and end-tidal CO2 tension were monitored during normocapnia and hypercapnia in 23 patients and 16 control subjects. Cerebrovascular CO2 responsiveness was quantified as Δ% Vmean and Δμmol/L cerebral oxyhemoglobin, deoxyhemoglobin, and total hemoglobin per mm Hg change in end-tidal CO2 tension. Both ways of measurements revealed lower cerebrovascular CO2 responsiveness in SCD patients versus controls (Vmean, 3.7, 3.1-4.7 vs 5.9, 4.6-6.7 Δ% Vmean per mm Hg, P < .001; oxyhemoglobin, 0.36, 0.14-0.82 vs 0.78, 0.61-1.22 Δμmol/L per mm Hg, P = .025; deoxyhemoglobin, 0.35, 0.14-0.67 vs 0.58, 0.41-0.86 Δμmol/L per mm Hg, P = .033; total-hemoglobin, 0.13, 0.02-0.18 vs 0.23, 0.13-0.38 Δμmol/L per mm Hg, P = .038). Cerebrovascular CO2 responsiveness was not related to markers of hemolytic anemia. In SCD patients, impaired cerebrovascular CO2 responsiveness reflects reduced cerebrovascular reserve capacity, which may play a role in pathophysiology of stroke.