title: Coronary flow reserve in sickle cell anemia.
abstract: BACKGROUND
  Patients with sickle cell anemia (SCA) frequently present with episodes of chest pain, alterations in the resting electrocardiogram, and changes in cardiac structure and functions.
  
  
  OBJECTIVE
  To evaluate the effect of recurrent episodes of vaso-occlusion on the coronary microcirculation.
  
  
  METHODS
  Coronary flow velocity and coronary flow reserve (CFR) of stable patients with SCA (n=10, 5 females, 24.4+/-5.4 years) were measured in the anterior descending coronary artery with transesophageal echocardiogram at baseline and after intravenous adenosine-induced maximum hyperemia, and compared to those of patients with sickle cell trait (TRA, n=10, 5 females, 27.7+/-3.2 years), iron deficiency anemia (IRO, n=8, 8 females, 26.6+/-5.2 years) and control group (NOR, n=10, 5 females, 26.3+/-6.3 years).
  
  
  RESULTS
  The SCA group presented increased diastolic coronary flow velocities (p<0.01) at baseline and during maximum hyperemia (67.3+/-14.0 and 198.2+/-37.9 cm/s, respectively) when compared with the other three groups - TRA (34.4+/-11.9 and 114.7+/-36.4 cm/s), IRO (42.4+/-10.4 and 141.0+/-18.7 cm/s) and NOR (38.1+/-10.0 and 126.8+/-24.6 cm/s). However, CFR was normal in the SCA group (3.0+/-0.7) and comparable (p=0.70) to the other groups - TRA (3.4+/-0.8), IRO (3.5+/-1.2), and NOR (3.4+/-0.8).
  
  
  CONCLUSIONS
  Despite the higher coronary flow velocities already observed at baseline and also during maximum hyperemia, CFR is normal in SCA, which suggests preserved coronary microcirculation. The episodes of vaso-occlusion are not responsible for the cardiologic findings in this disease.
authors.affiliation: Instituto do Coração, Hospital das Clínicas, FM, USP, São Paulo, SP, Brazil. jleaojunior@cardiol.br
authors.forename: José Leão
authors.initials: JL
authors.lastname: de Souza
authors.forename: Ana Clara Tude
authors.initials: AC
authors.lastname: Rodrigues
authors.forename: Paula Cássia
authors.initials: PC
authors.lastname: Buck
authors.forename: Sandra Fátima Menosi
authors.initials: SF
authors.lastname: Guallandro
authors.forename: Charles
authors.initials: C
authors.lastname: Mady
mesh_terms: D000328:Adult; D000755:Anemia, Sickle Cell / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001783:Blood Flow Velocity / Q000502:physiology*; D016022:Case-Control Studies; D003326:Coronary Circulation / Q000502:physiology*; D018618:Echocardiography, Doppler, Color; D017548:Echocardiography, Transesophageal; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011446:Prospective Studies