Study of the adrenergic heart innervation with iodine 123-metaiodobenzylguanidine in heart failure before transplantation.

ABSTRACT

BACKGROUND: The incidence and prevalence of heart failure (HF) are constantly increasing. Heart failure depends on pump failure, inflammatory tracers, and the neurohormonal system. At advanced stages, the only treatment is heart transplantation (HT). We studied myocardial innervation in patients before HT. MATERIALS AND METHODS: The study included 15 patients (11 men and 4 women; age range, 18-69 years) with a diagnosis of New York Heart Association class III-IV or IV HF. Planar thoracic images were obtained, at 15 minutes and 4 hours after injection of 10 mCi of iodine 123-metaiodobenzylguanidine ((123)I-MIBG). Adrenal activity was measured quantitatively using a heart-to-mediastinum count ratio and a myocardial washout rate. Pathologic results were considered if heart-to-mediastinum count ratio was less than 1.8 and washout rate was more than 35%. RESULTS: The qualitative analysis revealed decreased (123)I-MIBG myocardial uptake in all patients. Using the quantitative scale, patients were classified into four groups, as follows group 1, physiologic innervation, no patients; group 2, mild myocardial adrenergic involvement, one patient (6.7%); group 3, moderate myocardial adrenergic involvement, five patients (33.3%); and group 4, severe myocardial adrenergic involvement, 9 patients (60%). The washout rate was pathologic in 11 of the 15 patients (73.3%). CONCLUSIONS: Scintigraphy using (123)I-MIBG is a useful method to evaluate prognosis in patients with advanced HF and can be used to assess transplantation priorities. It will be necessary to study a larger number of patients to confirm these findings.