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 123 I-metaiodobenzylguanidine ( 123 I-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 123 I-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' 123 I-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 6 1.82 y. The baseline H/M ratio and WR; follow-up % denervation, H/M ratio, and WR; D-% denervation, H/M ratio, and WR; baseline LVEF; follow-up LVEDV, LVESV, and LVEF; and D-LVEDV, D-LVESV, and D-LVEF were significantly worse in the cardiac death group. A Cox regression analysis showed that the D-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 D-WR was an incremental predictor of sudden death. The cardiac death-free rate and sudden death-free rate were significantly higher in patients with D-WR less than 25% and D-WR less than 22% than in patients with D-WR greater than or equal to 25% and D-WR greater than or equal to 22%. Conclusion: D-WR obtained from serial 123 I-MIBG scintigraphic studies can be useful for predicting cardiac death and sudden death in stabilized patients with CHF.

Nuclear Molecular Imaging of the Failing Heart

“…Increased sympathetic nervous activity or denervation are seen in heart failure patients, and could be imaged with myocardial 123 I-MIBG image (16). Several reports have shown the clinical usefulness of 123 I-MIBG for prediction of major cardiac events, including heart failure hospitalization or cardiac death (17)(18)(19)(20), discharge of implantable cardioverter defibrillator (21), or evaluation of the effectiveness of betablockade (22)(23)(24)(25)(26), renin-angiotensin-aldosterone system inhibitor (27)(28)(29), and nicorandil (30,31) in patients with heart failure. And, a multi-center study of ADMIRE-HF (AdreView Myocardial Imaging for Risk Evaluation in Heart Failure) trial was conducted (32), and meta-analysis of Japanese-single cohort was also performed (33) and verified the perceptions of the previous studies.…”

Cardiac autonomic imaging with SPECT tracers

“…As interpretation of planar images requires analysis of the upper mediastinum, there is concern that smaller field of view cardiac cameras, or performing SPECT imaging alone, would not be suitable for cardiac 123 ImIBG imaging. However, a recent study by Chen et al 47 reported development of a technique to derive satisfactory quantitative parameters for SPECT imaging limited to the cardiac field…”

“…Most clinical and published work use a low energy high-resolution (LEHR) collimator, although slight differences among collimators in different countries (US vs Europe vs Japan) yield slightly different normal quantitative values. However, because of septal penetration by higher energy ([400 keV) 123 I photons, mostly a 529-keV emission, some have recommended using a medium energy collimator that has been shown to provide superior quantitative accuracy. 36,43,44 To compensate for the resulting corruption of image quantitation related to LEHR collimator penetration by higher energy photons, Chen et al 45,46 have developed a mathematical technique (iterative reconstruction with deconvolution of septal penetration) that appears to improve quantitative accuracy of cardiac 123 I-mIBG uptake in reference to a phantom standard.…”

“…34 Shortly thereafter, efforts at Michigan shifted toward positron emission tomography (PET) compounds, resulting in clinical mIBG studies thereafter being performed mostly in Europe and Japan. While early in development, mIBG was labeled with 131 I, high energy emissions (365 keV), including b -particles, and the 8-day half-life led to use of 123 I that emits predominantly 159-keV gamma photons, with a half-life of 13.2 h, thus well-tolerated and easily imaged with single-photon emission computed tomography (SPECT). Unlike NE, after uptake in the pre-synaptic terminal via the NET-1 pathway, 123 I-mIBG is not catabolized, and thereby localizes to a high cytoplasmic concentration.…”

“…35,37 Figure 3 shows examples of normal and abnormal global cardiac 123 I-mIBG uptake. 123 I-mIBG washout, i.e., the difference in cardiac activity between early and late planar images (compensated for radioactive decay), may reflect turnover of catecholamines attributable to sympathetic drive, and measures the ability of myocardium to retain tracer. The level of circulating catecholamines may also affect washout.…”