Usefulness of cardiac iodine-123 meta-iodobenzylguanidine imaging to improve prognostic power of Seattle heart failure model in patients with chronic heart failure

Validation of a Five-Year Prognostic Model Using 123I-metaiodobenzylguanidine Scintigraphy in Patients with Heart Failure

Background: 123I-metaiodobenzylguanidine (MIBG) scintigraphy evaluates the severity and prognosis of patients with heart failure. A prognostic model has been proposed using a multicenter study data of 123I-MIBG scintigraphy. We evaluated the usefulness of the model using a database. Methods: The study included 208 patients with noncompensated heart failure requiring hospitalization. 123I-MIBG scintigraphy and echocardiography were performed predischarge and 6 months postdischarge. The 5-year mortality rate was calculated by the model and classified into tertiles. Results: In 208 patients, 56 cardiac deaths occurred within the observation period (median, 4.83 years). In the evaluation of predischarge parameters, the predicted 5-year mortality was 15.5% ± 5.0%, 33.5% ± 3.9%, and 51.2% ± 8.2%, and 11 (16.2%), 18 (27.3%), and 27 (36.5%) cardiac deaths occurred in groups 1, 2, and 3, respectively. At the 6-month postdischarge evaluation, the estimated mortality was 8.2% ± 2.2%, 18.5% ± 4.8%, and 43.0% ± 12.1%, and 6 (9.4%), 21 (29.2%), and 29 (40.3%) cardiac deaths occurred, respectively. The predischarge Kaplan-Meier survival analysis showed significant difference between groups 1 and 3 (P value 0.014). Moreover, the 6-month postdischarge evaluation showed significant difference between group 1 and 2, and between groups 1 and 3 (P value 0.016, <0.001, respectively). For groups 1 and 3, the 6-month postdischarge difference was more significant than the predischarge difference (Chi-square 16.7 and 8.1, respectively). Conclusions: The prognostic model using 123I-MIBG scintigraphy was useful in predicting mortality risk in patients with heart failure. The estimated mortality at 6 months postdischarge was more useful than the predischarge estimation for heart failure hospitalization.

Prognostic significance of cardiac I-123-metaiodobenzylguanidine imaging in patients with reduced, mid-range, and preserved left ventricular ejection fraction admitted for acute decompensated heart failure: a prospective study in Osaka Prefectural Acute Heart Failure Registry (OPAR)

AIMS

Cardiac 123I-metaiodobenzylguanidine (123I-MIBG) imaging provides prognostic information in patients with chronic heart failure (HF). However, there is little information available on the prognostic role of cardiac 123I-MIBG imaging in patients admitted for acute decompensated heart failure (ADHF), especially relating to reduced ejection fraction [HFrEF; left ventricular ejection fraction (LVEF) < 40%], mid-range ejection fraction (HFmrEF; 40% ≤ LVEF < 50%) and preserved ejection fraction (HFpEF; LVEF ≥ 50%).

METHODS AND RESULTS

We studied 349 patients admitted for ADHF and discharged with survival. Cardiac 123I-MIBG imaging, echocardiography, and venous blood sampling were performed just before discharge. The cardiac 123I-MIBG heart-to-mediastinum ratio (late H/M) was measured on the chest anterior view images obtained at 200 min after the isotope injection. The endpoint was cardiac events defined as unplanned HF hospitalization and cardiac death. During a follow-up period of 2.1 ± 1.4 years, 128 patients had cardiac events (45/127 in HFrEF, 28/78 in HFmrEF, and 55/144 in HFpEF). On multivariable Cox analysis, late H/M was significantly associated with cardiac events in overall cohort (P = 0.0038), and in subgroup analysis of each LVEF subgroup (P = 0.0235 in HFrEF, P = 0.0119 in HFmEF and P = 0.0311 in HFpEF). Kaplan-Meier analysis showed that patients with low late H/M (defined by median) had significantly greater risk of cardiac events in overall cohort (49% vs. 25% P < 0.0001) and in each LVEF subgroup (HFrEF: 48% vs. 23% P = 0.0061, HFmrEF: 51% vs. 21% P = 0.0068 and HFpEF: 50% vs. 26% P = 0.0026).

CONCLUSION

Cardiac sympathetic nerve dysfunction was associated with poor outcome in ADHF patients irrespective of HFrEF, HFmrEF, or HFpEF.

Incremental prognostic value of cardiac metaiodobenzylguanidine imaging over the co-morbid burden in acute decompensated heart failure

Aims

Co‐morbidities are associated with poor clinical outcomes in patients with chronic heart failure, while cardiac iodine‐123 (I‐123) metaiodobenzylguanidine (MIBG) imaging provides prognostic information in such patients. We sought to prospectively investigate the incremental prognostic value of cardiac MIBG imaging over the co‐morbid burden, in patients admitted for acute decompensated heart failure (ADHF).

Methods and results

In 433 consecutive ADHF patients with survival to discharge, we measured the co‐morbidity using age‐adjusted Charlson co‐morbidity index (ACCI), commonly employed to evaluate a weighted and scored co‐morbid condition, adding additional points for age. In cardiac MIBG imaging, the cardiac MIBG heart‐to‐mediastinum ratio (late HMR) was measured on the delayed image. Over a follow‐up period of 2.9 ± 1.5 years, 160 patients had a cardiac event (a composite of cardiac death and unplanned hospitalization for worsening heart failure). Patients with high ACCI (≥6: median value) had a significantly greater risk of a cardiac event. In multivariate Cox analysis, the ACCI and late HMR were significantly and independently associated with a cardiac event. In both high and low ACCI subgroups (ACCI ≥ 6 and <6, respectively), patients with low late HMR had a significantly greater risk of a cardiac event (high ACCI: 51% vs. 34% P = 0.0026, adjusted HR 1.74 [1.21–2.51]; low ACCI: 34% vs. 17%, P = 0.0228, adjusted HR 2.19 [1.10–4.37]).

Conclusions

Cardiac MIBG imaging could provide additional prognostic information over ACCI, which was also promoted to be a useful risk model, in patients admitted for ADHF.

Prediction of sudden cardiac death in chronic heart failure patients with reduced ejection fraction by ADMIRE-HF risk score and early repolarization pattern

BACKGROUND

AdreView myocardial imaging for risk evaluation in heart failure (ADMIRE-HF) risk score is a novel risk score to predict serious arrhythmic risk in chronic heart failure patients with reduced ejection fraction (HFrEF). Moreover, early repolarization pattern (ERP) has been shown to be associated with an increased risk of sudden cardiac death (SCD) in HFrEF patients. We sought to investigate the prognostic value of combining ADMIRE-HF risk score and ERP to predict SCD in HFrEF patients.

METHODS

We studied 90 HFrEF outpatients with LVEF< 40% in our prospective cohort study. In cardiac MIBG imaging, the heart-to-mediastinum (H/M) ratio was measured on the delayed planar image. ADMIRE-HF risk score was derived from the sum of the point values of LVEF, H/M ratio, and systolic blood pressure. We also assessed ERP on the standard electrocardiogram.

RESULTS

During a median follow-up of 7.5(4.5-12.0) years, 22 patients had SCD. At multivariate Cox analysis, ADMIRE-HF risk score and ERP were independently associated with SCD. Patients with both intermediate/high ADMIRE-HF score and ERP had a higher SCD risk than those with either and none of them.

CONCLUSION

The combination of ADMIRE-HF risk score and ERP would provide the incremental prognostic information for predicting SCD in HFrEF patients.

Prediction of sudden cardiac death in patients with chronic heart failure by regional washout rate in cardiac MIBG SPECT imaging

BACKGROUND

The sympathetic nervous system provides an important trigger for major arrhythmic events through regional heterogeneity of sympathetic activity, which could be evaluated by SPECT imaging as the regional MIBG washout rate (WR). There is little information available on the prognostic value of regional WR in SPECT imaging for the prediction of sudden cardiac death (SCD) in patients with chronic heart failure (CHF).

METHODS

We studied 73 CHF outpatients with LVEF < 40%. At study entry, the regional WR was measured in 17 segments on the polar map. We defined abnormal regional WR as both the regional WR range (maximum - minimum regional WR) and maximum regional WR > mean value + 2SD obtained in 15 normal controls.

RESULTS

During a mean follow-up of 7.5 ± 4.1 years, 15 of 73 patients had SCD. The abnormal regional WR and abnormal global WR on planar images were significantly and independently associated with SCD. Patients with both the abnormal regional WR and global WR had a significantly higher risk of SCD than those with none of these criteria.

CONCLUSIONS

The analysis of regional MIBG WR on SPECT imaging provides additional prognostic value to global WR on planar images for SCD prediction in CHF patients.

Usefulness of Cardiac MetaIodobenzylguanidine Imaging to Improve Prognostic Power of the Model for End-Stage Liver Disease Scoring System in Patients With Mild-to-Moderate Chronic Heart Failure

Liver dysfunction has a prognostic impact on the outcomes of patients with advanced heart failure (HF). The model for end-stage liver disease (MELD) score is a robust system for rating liver dysfunction, and a high score has been shown to be associated with a poor prognosis in ambulatory patients with HF. In addition, cardiac metaiodobenzylguanidine (MIBG) imaging provides prognostic information in patients with chronic HF (CHF). However, the long-term predictive value of combining the MELD score and cardiac MIBG imaging in patients with CHF has not been elucidated. To prospectively investigate whether cardiac MIBG imaging provides additional prognostic value to the MELD score in patients with mild-to-moderate CHF, we studied 109 CHF outpatients (New York Heart Association: 2.0 ± 0.6) with left ventricular ejection fraction <40%. At enrollment, an MELD score was obtained, and the heart-to-mediastinal ratio on delayed imaging and MIBG washout rate (WR) were measured using cardiac MIBG scintigraphy. During a follow-up period of 7.5 ± 4.2 years, 36 of 109 patients experienced cardiac death (CD). On multivariate Cox analysis, MELD score and WR were significantly independently associated with CD, although heart-to-mediastinal ratio showed an association with CD only on univariate Cox analysis. Patients with abnormal WR (>27%) had a significantly greater risk of CD than those with normal WR in both those with high MELD scores (≥10; hazard ratio 4.0 [1.2 to 13.6]) and with low MELD scores (<10; hazard ratio 6.4 [1.7 to 23.2]). In conclusion, cardiac MIBG imaging would provide additional prognostic information to the MELD score in patients with mild-to-moderate CHF.

Is cardiopulmonary exercise testing essential to indicate ventricular assist device implantation in patients with INTERMACS profile 4-7?

Cardiopulmonary exercise testing (CPXT) is a promising tool for predicting 2-year cardiac death or ventricular assist device (VAD) implantation in patients assigned to INTERMACS profile 4-7. However, CPXT is not available in all hospitals. We evaluated 130 patients <65 years old with advanced heart failure assigned to INTERMACS profile 4-7 who underwent CPXT. CPXT scores (0-8 points), which we created recently, and the Seattle HF Model (SHFM) scores were both significant predictors of 2-year cardiac death or VAD implantation (14 events) by Cox-regression analysis (P < 0.05 for both) and had comparable areas under the curve (AUCs) in receiver operating characteristic analyses (0.811 vs. 0.737, P > 0.05). The combination score: age <46 years and serum sodium concentration <137 mEq/L, both of which were significant predictors of cardiac death or VAD implantation by uni/multivariate Cox-regression analyses, had a significantly higher AUC than did CPXT scores (0.909, P < 0.05). In a validation study, the AUC of the combination score was comparable with that of SHFM among 52 patients <65 years old receiving adaptive servo-ventilator treatment (0.753 vs. 0.794, P > 0.05). In conclusion, VAD indication may be discussed without CPXT in patients <65 years old with INTERMACS profile 4-7 at least in the current Japanese situation.

Prognostic Value of Cardiac Sympathetic Nerve Imaging Using Long-Term Follow-up Data - Ischemic vs. Non-Ischemic Heart Failure Etiology

BACKGROUND

Although there are several known prognostic determinants in heart failure (HF), individual risk profiles can vary, in particular between ischemic and non-ischemic HF background. This study investigated the difference in prognostic efficacy of cardiac (123)I-meta-iodobenzylguanidine (MIBG) imaging between the 2 etiologies.

METHODS AND RESULTS

All 1,322 patients with HF were enrolled and followed up at most after 10 years. The HF patients were divided into 2 groups: an ischemic group (n=362) and non-ischemic group (n=960), and Cox proportional hazards model was used for data analysis. During 10 years of follow-up, 296 (22.4%) of 1,322 patients died; the mortality rates were 21.8% and 22.6% for the ischemic and non-ischemic groups, respectively. The ischemic group had greater prevalence of sudden death and lethal acute myocardial infarction, and the non-ischemic group had a higher rate of pump failure death. On multivariate Cox proportional hazards analysis using categorized variables, in the ischemic group, delayed heart-to-mediastinum ratio (HMR; P<0.0001), age (P=0.0002) and LVEF (P=0.03) were the independent significant predictors of lethal events. In the non-ischemic group, delayed HMR (P<0.0001), NYHA class (P<0.0001) and age (P<0.0001) were significant determinants of lethal outcome.

CONCLUSIONS

Cardiac MIBG imaging has nearly identical prognostic value in both ischemic and non-ischemic HF, independent of cause of cardiac death.

Usefulness of cardiac meta-iodobenzylguanidine imaging to identify patients with chronic heart failure and left ventricular ejection fraction <35% at low risk for sudden cardiac death

Patients with chronic heart failure (CHF) at risk of sudden cardiac death (SCD) are often treated with implantable cardiac defibrillators (ICDs). However, current criteria for device use that is based largely on left ventricular ejection fraction (LVEF) lead to many patients receiving ICDs that never deliver therapy. It is of clinical significance to identify patients who do not require ICDs. Although cardiac I-123 meta-iodobenzylguanidine (MIBG) imaging provides prognostic information about CHF, whether it can identify patients with CHF who do not require an ICD remains unclear. We studied 81 patients with CHF and LVEF <35%, assessed by cardiac MIBG imaging at enrollment. The heart-to-mediastinal ratio (H/M) in delayed images and washout rates were divided into 6 grades from 0 to 5, according to the degree of deviation from control values. The study patients were classified into 3 groups: low (1 to 4), intermediate (5 to 7), and high (8 to 10), according to the MIBG scores defined as the sum of the H/M and washout rate scores. Sixteen patients died of SCD during a follow-up period. Patients with low MIBG score had a significantly lower risk of SCD than those with intermediate and high scores (low [n = 19], 0%; intermediate [n = 37], 19%; high [n = 25], 36%; p = 0.001). The positive predictive value of low MIBG score for identifying patients without SCD was 100%. In conclusion, the MIBG score can identify patients with CHF and LVEF <35% who have low risk of developing SCD.

Incremental utility of iodine-123 meta-iodobenzylguanidine imaging beyond established heart failure risk models

BACKGROUND

Nuclear myocardial imaging with iodine-123 meta-iodobenzylguanidine ((123)I-mIBG) is approved for risk stratification of patients with systolic heart failure (HF). Whether (123)I-mIBG imaging provides incremental prognostic utility beyond established risk models remains unclear.

METHODS AND RESULTS

In a multicenter study, 961 patients with moderate systolic HF underwent (123)I-mIBG imaging and were followed for cardiac death, progressive HF, or life-threatening arrhythmias over 2 years. We constructed 4 multivariable models, using variables from each of 4 published HF risk models, and patient-level scores were calculated both before and after adding the heart-to-mediastinum ratio (H/M) from (123)I-mIBG imaging. Incremental utility was evaluated by calculating integrated discrimination improvement (IDI), which quantifies the increase in probability of experiencing the primary end point after adding H/M to each model. The composite end point occurred in 25% of patients. After adding H/M, absolute IDI ranged from 2.1% to 3.0%, representing 33%-59% relative improvements in risk stratification. Of note, hazard ratios for H/M were remarkably similar between risk models (0.40-0.44 for predicting the composite end point, 0.10-0.18 for mortality; all P < .001).

CONCLUSIONS

Despite notable differences in predictor variables, patient populations, and analytic techniques from which each model was initially derived, adding (123)I-mIBG data to HF risk models consistently identified patients at lower risk of experiencing adverse events.

A prediction model for 5-year cardiac mortality in patients with chronic heart failure using ¹²³I-metaiodobenzylguanidine imaging

Purpose

Prediction of mortality risk is important in the management of chronic heart failure (CHF). The aim of this study was to create a prediction model for 5-year cardiac death including assessment of cardiac sympathetic innervation using data from a multicenter cohort study in Japan.

Methods

The original pooled database consisted of cohort studies from six sites in Japan. A total of 933 CHF patients who underwent ¹²³I-metaiodobenzylguanidine (MIBG) imaging and whose 5-year outcomes were known were selected from this database. The late MIBG heart-to-mediastinum ratio (HMR) was used for quantification of cardiac uptake. Cox proportional hazard and logistic regression analyses were used to select appropriate variables for predicting 5-year cardiac mortality. The formula for predicting 5-year mortality was created using a logistic regression model.

Results

During the 5-year follow-up, 205 patients (22 %) died of a cardiac event including heart failure death, sudden cardiac death and fatal acute myocardial infarction (64 %, 30 % and 6 %, respectively). Multivariate logistic analysis selected four parameters, including New York Heart Association (NYHA) functional class, age, gender and left ventricular ejection fraction, without HMR (model 1) and five parameters with the addition of HMR (model 2). The net reclassification improvement analysis for all subjects was 13.8 % (p < 0.0001) by including HMR and its inclusion was most effective in the downward reclassification of low-risk patients. Nomograms for predicting 5-year cardiac mortality were created from the five-parameter regression model.

Conclusion

Cardiac MIBG imaging had a significant additive value for predicting cardiac mortality. The prediction formula and nomograms can be used for risk stratifying in patients with CHF.

Electronic supplementary material

The online version of this article (doi:10.1007/s00259-014-2759-x) contains supplementary material, which is available to authorized users.

Cardiac I123-MIBG correlates better than ejection fraction with symptoms severity in systolic heart failure

Background

The association of autonomic activation, left ventricular ejection fraction (LVEF) and heart failure functional class is poorly understood.

Objective

Our aim was to correlate symptom severity with cardiac sympathetic activity, through iodine-123-metaiodobenzylguanidine (¹²³I-MIBG) scintigraphy and with LVEF in systolic heart failure (HF) patients without previous beta-blocker treatment.

Methods

Thirty-one patients with systolic HF, class I to IV of the New York Heart Association (NYHA), without previous beta-blocker treatment, were enrolled and submitted to ¹²³I-MIBG scintigraphy and to radionuclide ventriculography for LVEF determination. The early and delayed heart/mediastinum (H/M) ratio and the washout rate (WR) were performed.

Results

According with symptom severity, patients were divided into group A, 13 patients in NYHA class I/II, and group B, 18 patients in NYHA class III/IV. Compared with group B patients, group A had a significantly higher LVEF (25% ± 12% in group B vs. 32% ± 7% in group A, p = 0.04). Group B early and delayed H/M ratios were lower than group A ratios (early H/M 1.49 ± 0.15 vs. 1.64 ± 0.14, p = 0.02; delayed H/M 1.39 ± 0.13 vs. 1.58 ± 0.16, p = 0.001, respectively). WR was significantly higher in group B (36% ± 17% vs. 30% ± 12%, p= 0.04). The variable that showed the best correlation with NYHA class was the delayed H/M ratio (r= -0.585; p=0.001), adjusted for age and sex.

Conclusion

This study showed that cardiac ¹²³I-MIBG correlates better than ejection fraction with symptom severity in systolic heart failure patients without previous beta-blocker treatment.

Iodine-123-metaiodobenzylguanidine scintigraphy in risk stratification of sudden death in heart failure

Metaiodobenzylguanidine (MIBG) is a false neurotransmitter noradrenaline analogue that is taken up by the 'uptake 1' transporter mechanism in the cell membrane of presynaptic adrenergic neurons and accumulates in catecholamine storage vesicles. Since it is practically unmetabolized, it can be labeled with a radioisotope (iodine-123) in scintigraphic exams to noninvasively assess the functional status of the sympathetic innervation of organs with a significant adrenergic component, including the heart. Studies of its application in nuclear cardiology appear to confirm its value in the assessment of conditions such as coronary artery disease, heart failure, arrhythmias and sudden death. Heart failure is a global problem, with an estimated prevalence of 2% in developed countries. Sudden cardiac death is the main cause of its high mortality. The autonomic nervous system dysfunction, including sympathetic hyperactivity, that accompanies chronic heart failure is associated with progressive myocardial remodeling, declining left ventricular function and worsening symptoms, and contributes to the development of ventricular arrhythmias and sudden death. Since 123I-MIBG cardiac scintigraphy can detect changes in the cardiac adrenergic system, there is considerable interest in its role in obtaining diagnostic and prognostic information in patients with heart failure. In this article we present a literature review on the use of 123I-MIBG scintigraphy for risk stratification of sudden death in patients with heart failure.

Selective improvement in Seattle Heart Failure Model risk stratification using iodine-123 meta-iodobenzylguanidine imaging

BACKGROUND

The Seattle Heart Failure Model (SHFM) is a multivariable model that uses demographic and clinical markers to predict survival in patients with heart failure. Inappropriate activation of the sympathetic nervous system, which contributes to the progression of heart failure and increased mortality, can be assessed using iodine-123 meta-iodobenzylguanidine (MIBG) cardiac imaging. This study investigated the incremental value of MIBG cardiac imaging when added to the SHFM for prediction of all-cause mortality.

METHODS

Survival data from 961 NYHA II-III subjects in the ADMIRE-HFX trial were included in this analysis. The predictive value of the SHFM alone and in combination with MIBG heart-to-mediastinum ratio (H/M) was compared for all-cause mortality (101 deaths during a median follow-up of 2 years).

RESULTS

The addition of H/M to the SHFM in a Cox model significantly improved risk prediction (P < .0001), with a greater utility in higher risk SHFM patients. The observed 2-year mortality in the highest-risk SHFM subjects (rounded SHFM score of 1) was 24%, but varied from 46% with H/M <1.2 to 0% with H/M >1.8. Net reclassification improvement was 22.7% (P < .001), with 14.9% of subjects who died reclassified into a higher risk category than suggested by SHFM score alone (P = .01) and 7.9% of subjects who survived reclassified into a lower risk category (P < .0001). The 2-year integrated discrimination improvement (+4.14%, P < .0001) and the 1-year area under the receiver-operator characteristic curve (+0.04, P = .026) both showed significant improvement for the combined model with H/M compared to the SHFM alone.

CONCLUSION

The addition of MIBG imaging to the SHFM improves risk stratification, especially in higher risk patients. MIBG may have clinical utility in higher risk patients who are being considered for devices such as ICD, CRT-D, LVAD, and cardiac transplantation.