Cerebrovascular reserve capacity is impaired in patients with sickle cell disease.
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 (V(mean)), 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 Delta% V(mean) and Deltamicromol/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 (V(mean), 3.7, 3.1-4.7 vs 5.9, 4.6-6.7 Delta% V(mean) per mm Hg, P < .001; oxyhemoglobin, 0.36, 0.14-0.82 vs 0.78, 0.61-1.22 Deltamicromol/L per mm Hg, P = .025; deoxyhemoglobin, 0.35, 0.14-0.67 vs 0.58, 0.41-0.86 Deltamicromol/L per mm Hg, P = .033; total-hemoglobin, 0.13, 0.02-0.18 vs 0.23, 0.13-0.38 Deltamicromol/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.
Nur
Erfan
E
Department of Internal Medicine, Slotervaart Hospital, Amsterdam, The Netherlands.
Kim
Yu-Sok
YS
Truijen
Jasper
J
van Beers
Eduard J
EJ
Davis
Shyrin C A T
SC
Brandjes
Dees P
DP
Biemond
Bart J
BJ
van Lieshout
Johannes J
JJ
D000328:Adult; D000755:Anemia, Sickle Cell / Q000097:blood / Q000150:complications / Q000453:epidemiology / Q000503:physiopathology*; D001783:Blood Flow Velocity; D002545:Brain Ischemia / Q000097:blood / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology*; D002245:Carbon Dioxide / Q000097:blood; D002560:Cerebrovascular Circulation; D005260:Female; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D015994:Incidence; D008297:Male; D009569:Nitric Oxide / Q000097:blood; D010100:Oxygen / Q000097:blood; D010108:Oxyhemoglobins / Q000032:analysis; D012307:Risk Factors; D020521:Stroke / Q000097:blood / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology*
D006454:Hemoglobins; D010108:Oxyhemoglobins; D002245:Carbon Dioxide; D009569:Nitric Oxide; C100003:deoxyhemoglobin; D010100:Oxygen