Arquivos Brasileiros de Cardiologia (May 2007)
Reserva de fluxo coronariano na anemia falciforme Coronary flow reserve in sickle cell anemia
Abstract
FUNDAMENTO: Pacientes com anemia falciforme (FAL) apresentam freqüentemente episódios de dor precordial, possuem alterações eletrocardiográficas em repouso e exibem alterações da estrutura e das funções cardíacas. OBJETIVO: Avaliar o efeito dos episódios repetitivos de vaso-oclusão sobre a microcirculação coronariana. MÉTODOS: Pacientes estáveis com FAL (n = 10, cinco mulheres, 24,4 + 5,4 anos) foram submetidos a medida das velocidades de fluxo coronariano e da reserva de fluxo coronariano (RFC) na artéria coronária descendente anterior por meio de ecocardiografia transesofágica em estado basal e após hiperemia máxima, obtida com adenosina intravenosa. Esses pacientes foram comparados a pacientes com traço falciforme (TRA, n = 10, cinco mulheres, 27,7 + 3,2 anos), anemia ferropriva (FER, n = 8, oito mulheres, 26,6 + 5,2 anos) e grupo controle (NOR, n = 10, cinco mulheres, 26,3 + 6,3 anos). RESULTADOS: O grupo FAL apresentou aumento das velocidades de fluxo coronariano diastólico (p 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). CONCLUSION: 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.
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