AdreView cardiac imaging agent Image source: GE Healthcare

Researchers prospectively evaluating AdreView, GE Healthcare's iodine-123 meta-iodobenzylguanidine (123I-mIBG) imaging agent, found that the agent identified symptomatic heart failure patients most likely to experience cardiac events, according to the ADMIRE-HF trial published in the May 18 issue of the Journal of the American College of Cardiology.

ADMIRE-HF (AdreView Myocardial Imaging for Risk Evaluation-Heart Failure) was designed to demonstrate that if the cardiac nerves are damaged or reduced in number, as reflected by reduced 123I-mIBG uptake in the heart, the patient is at increased risk for heart failure progression, arrhythmic events and cardiac death. The study consisted of two identical open-label phase III clinical studies evaluating the cardiac sympathetic nerves at the cellular level.

A total of 961 subjects with New York Heart Association (NYHA) functional class II/III symptomatic HF and left ventricular ejection fraction (LVEF) 35 percent were studied by Jagat Narula, MD, PhD, professor of medicine and chief of division of cardiology at University of California at Irvine, and colleagues.

All the subjects underwent 123I-mIBG myocardial SPECT imaging (sympathetic neuronal integrity quantified as the heart/mediastinum uptake ratio [H/M] on four-hour delayed planar images) and myocardial perfusion imaging and were then followed up for up to two years.

A total of 237 subjects (25 percent) experienced first cardiac events within the median follow-up of 17 months, according to Narula and colleagues.

Researchers used the heart/mediastinum ratio (H/M) to assess the functionality of the sympathetic nerves; H/M is a ratio of the nerve function in the heart compared to that of a reference background region in the mediastinum (the mass of tissues and organs between the two pleural sacs, which separate the heart from the lungs). 

Two-year event rate was 15 percent for H/M 1.60 and 37 percent for H/M less than 1.60; hazard ratios for individual event categories were as follows: HF progression, 0.49; arrhythmic events, 0.37; and cardiac death, 0.14.

Significant contributors to the multivariable model were H/M, LVEF, B-type natriuretic peptide, and NYHA functional class. 123I-mIBG imaging also provided additional discrimination in analyses of interactions between B-type natriuretic peptide, LVEF and H/M.

“Increased cardiac sympathetic activity is a prominent feature of heart failure and is associated with progressive deterioration and remodeling of the myocardium, inexorable decline in left ventricular function, and worsening symptoms,” said senior author Roxy Senior, MD, director of cardiac research at Northwick Park Hospital in London. “Our results suggest that in appropriately selected patients with heart failure, the 123I-mIBG imaging procedure can alert clinicians to the potential need for considering additional treatments.”