RESUMO
OBJECTIVES: This prospective study was undertaken to correlate early and late metaiodobenzylguanidine (MIBG) cardiac uptake with cardiac hemodynamics and exercise capacity in patients with heart failure and to compare their prognostic values with that of peak oxygen uptake (VO2). BACKGROUND: The cardiac fixation of MIBG reflects presynaptic uptake and is reduced in heart failure. Whether it is related to exercise capacity and has better prognostic value than peak VO2 is unknown. METHODS: Ninety-three patients with heart failure (ejection fraction <45%) were studied with planar MIBG imaging, cardiopulmonary exercise tests and hemodynamics (n = 44). Early (20 min) and late (4 h) MIBG acquisition, as well as their ratio (washout, WO) were determined. Prognostic value was assessed by survival curves (Kaplan-Meier method) and uni- and multivariate Cox analyses. RESULTS: Late cardiac MIBG uptake was reduced (131+/-20%, normal values 192+/-42%) and correlated with ejection fraction (r = 0.49), cardiac index (r = 0.40) and pulmonary wedge pressure (r = -0.35). There was a significant correlation between peak VO2 and MIBG uptake (r = 0.41, p < 0.0001). With a mean follow-up of 10+/-8 months, both late MIBG uptake (p = 0.04) and peak VO2 (p < 0.0001) were predictive of death or heart transplantation, but only peak VO2 emerged by multivariate analysis. Neither early MIBG uptake nor WO yielded significant insights beyond those provided by late MIBG uptake. CONCLUSIONS: Metaiodobenzylguanidine uptake has prognostic value in patients with wide ranges of heart failure, but peak VO2 remains the most powerful prognostic index.
Assuntos
3-Iodobenzilguanidina , Insuficiência Cardíaca/diagnóstico por imagem , Miocárdio/metabolismo , Consumo de Oxigênio , Compostos Radiofarmacêuticos , 3-Iodobenzilguanidina/farmacocinética , Adulto , Idoso , Doença Crônica , Teste de Esforço , Tolerância ao Exercício , Feminino , Seguimentos , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/fisiopatologia , Hemodinâmica , Humanos , Radioisótopos do Iodo , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Curva ROC , Ventriculografia com Radionuclídeos , Compostos Radiofarmacêuticos/farmacocinética , Índice de Gravidade de DoençaRESUMO
The prognosis of patients with coronary artery disease may be threatened by ischaemic mitral regurgitation. Apart from rupture of a papillary muscle which requires rapid valve replacement. Chronic ischaemic papillary muscle dysfunction can often be a severe complication of ischaemic heart disease. The authors report the case of a patient with dyspnoea but no angina of effort. Cardiovascular investigations with right heart catheterisation demonstrated the occurrence of severe mitral regurgitation only during angioplasty of the left marginal artery.