Peptídeo natriurético B na distrofia muscular de Duchenne
USA – o peptídeo natriurético tipo B aumenta na disfunção cardíacas em diversas situações como na cardiopatia da distrofia muscular de Duchenne. Nesta pesquisa este fator foi dosado com o objetivo de avaliar se a sua elevação poderia ser uma maneira de determinar precocemente a doença cardíaca na distrofia muscular. O resultado desta pesquisa mostrou que o peptídeo natriurético tipo B está normal em pacientes com Duchenne e que apresentam disfunção cardíaca assintomática e muito pouco elevado em reduções importantes da função cardíaca. Este resultado demonstra que a dosagem do peptídeo natriurético B não tem utilidade para diagnóstico precoce da distrofia muscular de Duchenne.
(IN PRESS:International Journal of Cardiology, 2006) B-type natriuretic peptide and cardiac dysfunction in Duchenne muscular dystrophy – Letter to the Editor
Tayyab Mohyuddin, Irwin B. Jacobs, Robert C. Bahler – USA
Serum levels of B-type natriuretic peptide have moderate utility for detection of early ventricular dysfunction in adults and in experimental muscular dystrophy. To determine if B-type natriuretic peptide levels are useful in the detection of early left ventricular dysfunction in Duchenne muscular dystrophy patients, measurements were obtained in 21 patients being evaluated by echocardiography for left ventricular dysfunction. Two patients with clinical evidence of heart failure were excluded (mean B-type natriuretic peptide level of 352 pg/ml). Age range of the remaining 19 patients was 9–21 yrs. Fractional shortening was abnormal (<30%) in 14/19 and early diastolic tissue Doppler velocities were abnormal in 13/16. In these patients B-type natriuretic peptide levels were clearly normal (<30 pg/ml) in 15/19 and only mildly elevated (30–80 pg/ml) in 4/19. The 4 patients with mildly elevated B-type natriuretic peptide had significantly lower fractional shortening (12.6±5.9 versus 19.8±5.3, p<0.05). In conclusion, B-type natriuretic peptide levels are normal in the majority of Duchenne muscular dystrophy patients with asymptomatic left ventricular dysfunction and only mildly elevated when fractional shortening is markedly reduced.
