ASSESSMENT OF ANTHRACYCLINE-RELATED MYOCARDIAL ADRENERGIC DERANGEMENTBY [I-123] METAIODOBENZYLGUANIDINE SCINTIGRAPHY

Myocardial adrenergic neuron integrity and function were evaluated in 21 patients who had received doxorubicin or epirubicin for various mal ignancies. Myocardial uptake of iodine-123 metaiodobenzylguanidine ([I -123]MIBG), a marker suitable for the study of myocardial neuron injur y, was calculated from planar scintigraphic images after 4 h and the w ashout between 15 min and 4 h. In 13 patients with normal left ventric le ejection fraction (LVEF) analysed at three cumulative dose levels ( no, low and middle dose), [I-123]MIBG uptake tended to be significantl y impaired (z = -2.772, P = 0.0056), at higher cumulative dose levels, before significant LVEF changes were observed. [I-123]MIBG values wer e considerably decreased in 2/7 patients investigated at low cumulativ e dose and in 3/8 cases at the middle dose level. On follow-up, 1 of t hese patients, who had normal LVEF after completion of chemotherapy bu t whose [I-123]MIBG values had progressively deteriorated during anthr acycline therapy, subsequently developed congestive heart failure; ano ther patient, whose [I-123]MIBG values were impaired at the middle dos e level, developed persistent reduced LVEF 5 months after completing t herapy. in 8 patients, who had developed persistently, reduced LVEF at high doxorubicin cumulative dose levels, [I-123]MIBG, performed in th e period after chemotherapy discontinuation, was invariably abnormal. These data suggest that myocardial adrenergic derangement plays a role in anthracycline-associated cardiotoxicity: its appearance, even at l ow cumulative anthracycline dose levels, may reflect impairment of the intravesicular norepinephrine storage by incipient anthracycline-asso ciated cardiac neuron injury. [I-123]MIBG scintigraphy may be useful t o assess myocardial adrenergic derangement during and in the follow-up of anthracycline therapy and potentially detect patients who are at r isk.