I-123-mIBG myocardial imaging for assessment of risk for a major cardiac event in heart failure patients: insights from a retrospective European multicenter study.
OBJECTIVE
Single-center experiences have shown that myocardial meta-iodobenzylguanidine (mIBG) uptake has prognostic value in heart failure (HF) patients. To verify these observations using a rigorous clinical trial methodology, a retrospective review and prospective quantitative reanalysis was performed on a series of cardiac (123)I-mIBG scans acquired during a 10-year period at six centers in Europe.


METHODS
(123)I-mIBG scans obtained on 290 HF patients [(262 with left ventricular ejection fraction (LVEF) < 50%)] from 1993 to 2002 were reanalyzed using a standardized methodology to determine the heart-to-mediastinum ratio (H/M) on delayed planar images. All image results were verified by three independent reviewers. Major cardiac events [MCEs; cardiac death, cardiac transplant, potentially fatal arrhythmia (including implantable cardioverter-defibrillator discharge)] during 24-month follow-up were confirmed by an adjudication committee.


RESULTS
MCEs occurred in 67 patients (26%): mean H/M ratio was 1.51 +/- 0.30 for the MCE group and 1.97 +/- 0.54 for the non-MCE group (p < 0.001). Two-year event-free survival using an optimum H/M ratio threshold of 1.75 was 62% for H/M ratio less than 1.75, 95% for H/M ratio greater than or equal to 1.75 (p < 0.0001). Logistic regression showed H/M ratio and LVEF as the only significant predictors of MCE. Using the lower and upper H/M quartiles of 1.45 and 2.17 as high- and very low-risk thresholds, 2-year event-free survival rates were 52% and 98%, respectively. Among patients with LVEF < or = 35% and H/M > or = 1.75 (n = 73), there were nine MCEs because of progressive HF and only one because of an arrhythmia.


CONCLUSIONS
Application of a clinical trial methodology via the retrospective reanalysis of (123)I-mIBG images confirms the previously reported prognostic value of this method in HF patients, including potential identification of a quantitative threshold for low risk for cardiac mortality and potentially fatal ventricular arrhythmias.
Agostini
Denis
D
CHU Cote de Nacre, Caen, France. agostini-de@chu-caen.fr
Verberne
Hein J
HJ
Burchert
Wolfgang
W
Knuuti
Juhani
J
Povinec
Pavol
P
Sambuceti
Gianmario
G
Unlu
Mustafa
M
Estorch
Montserrat
M
Banerjee
Gopa
G
Jacobson
Arnold F
AF
D019797:3-Iodobenzylguanidine; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D005060:Europe; D006321:Heart / Q000000981:diagnostic imaging*; D006333:Heart Failure / Q000000981:diagnostic imaging*; D006801:Humans; D008875:Middle Aged; D011379:Prognosis; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D012680:Sensitivity and Specificity; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*
D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine