Prognostic value of serial cardiac 123I-MIBG imaging in patients with stabilized chronic heart failure and reduced left ventricular ejection fraction

Abstract

Many studies have shown that a one-time 123I-metaiodobenzylguanidine (123I-MIBG) scintigraphic study during a stable period is useful for determining the prognosis of patients with chronic heart failure (CHF). However, the findings from this imaging modality are well known to be improved by medical treatment for heart failure. Accordingly, this study was performed to determine whether serial 123I-MIBG scintigraphic studies represent a reliable prognostic marker for patients with CHF.

Methods: A total of 208 patients with CHF (left ventricular ejection fraction [LVEF] < 45%) and with no cardiac events for at least 5 mo were identified on the basis of a history of decompensated acute heart failure requiring hospitalization. The delayed percentage of denervation (% denervation), delayed heart-to-mediastinum count (H/M) ratio, and washout rate (WR) were determined from the patients' 123I-MIBG images just before they left the hospital and after they had received 6 mo of treatment. The left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), and LVEF were also determined by echocardiography at the same time points.

Results: Of the 208 patients, 56 experienced fatal cardiac events during the study. The mean follow-up period was 4.45 +/- 1.82 y. The baseline H/M ratio and WR; follow-up % denervation, H/M ratio, and WR; Delta-% denervation, H/M ratio, and WR; baseline LVEF; follow-up LVEDV, LVESV, and LVEF; and Delta-LVEDV, Delta-LVESV, and Delta-LVEF were significantly worse in the cardiac death group. A Cox regression analysis showed that the Delta-WR was an independent predictor of cardiac death. Moreover, sudden death occurred in 13 of the 56 patients with cardiac death. A Cox regression analysis also showed that the Delta-WR was an incremental predictor of sudden death. The cardiac death-free rate and sudden death-free rate were significantly higher in patients with Delta-WR less than -5% and Delta-WR less than -2% than in patients with Delta-WR greater than or equal to -5% and Delta-WR greater than or equal to -2%.

Conclusion: Delta-WR obtained from serial 123I-MIBG scintigraphic studies can be useful for predicting cardiac death and sudden death in stabilized patients with CHF.