First Imaging Agent Approved for Visualization of Myocardial Sympathetic Innervation in Specific Heart Failure Patients

A new imaging agent has been approved in the United States for the scintigraphic evaluation of myocardial sympathetic innervation (cardiac nerve activity) to help in the assessment of patients with New York Heart Association (NYHA) class II or class III heart failure and left ventricular ejection fraction (LVEF) ≤ 35%. The agent will help identify patients with one and two-year mortality risks as indicated by an H/M ratio >1.6.

GE Healthcare (Chalfont St. Giles, UK) reported on the US Food and Drug Administration (FDA) approval of a new indication for AdreView (iobenguane I 123 injection), the first and only US Food and Drug Administration (FDA)-approved molecular imaging agent to link nerve function in the heart to a patient’s mortality risk. In patients with congestive heart failure (CHF), utility has not been established for choosing therapy, tracking response to therapy, or to identify a patient with high risk of death.

“Predicting disease progression in heart failure patients can be difficult, and there are currently a limited number of prognostic tools available to help clinicians understand the likelihood for heart failure progression,” said James Arrighi, MD, associate professor of medicine, Brown University (Providence, RI, USA), and current president of the American Society of Nuclear Cardiology. “Now, with AdreView, we have a tool that will provide clinicians with a numeric score to help stratify mortality risk, and may help to promote more informed clinical decision-making.”

Increased myocardial sympathetic activity is a key characteristic of heart failure and is frequently associated with decline in left ventricular function, worsening heart failure symptoms, and sudden cardiac death. This increase leads to a depletion of norepinephrine (NE) storage and uptake. AdreView offers a way to evaluate the neuronal capacity for uptake and storage of NE. While current prognostic tests look at the effect of the disease on heart muscle and blood flow, imaging with AdreView utilizes the heart to mediastinum (H/M) ratio to evaluate the functionality of the sympathetic nerves.

The H/M ratio, with the agent, is a measure of radioactivity uptake in the heart compared to that of a reference region in the mediastinum. This measurement has a typical range of 1–2.4 and can effectively identify patients with lower than average one- and two- year mortality risk. In clinical studies, an AdreView Score (H/M ratio) of ≥ 1.6 was linked with a 99% likelihood of survival at one year (negative predictive value [NPV]).

“GE Healthcare is committed to providing innovative and effective medical products that will aid physicians in determining mortality risk in patients with cardiovascular disease, and we are pleased that the FDA has approved AdreView for this indication in heart failure patients,” said Terri Moench, general manager, single photon emission tomography (SPECT), GE Healthcare medical diagnostics. “The use of imaging tests is consistent with current trends towards gaining improved and earlier understanding of heart disease at a molecular level and may enable providers to help deliver better care to more people.

The safety and efficacy of AdreView were evaluated in two open-label, multicenter, international trials in 985 patients with NYHA class II or class III heart failure with LVEF < 35%. A total of 110 patients without a history of heart disease also received a single dose of AdreView. The endpoint for analysis was all-cause mortality, an outcome confirmed by review of an independent adjudication committee. By 12 months after enrollment among the 964 heart failure patients in the efficacy population, 50 (5%) patients had died, 61 (6%) had missing follow-up data, and 3 patients had missing H/M ratios. One-year mortality rates in relation to AdreView H/M ratio were < 1.2: 13.4%; 1.2-1.6: 5.5%; ≥ 1.6: 1.0%. By 23 months following enrollment (the requirement for designation of two-year follow-up), 96 (10%) patients had died, 201 (21%) patients had missing follow-up information and 3 patients were missing H/M ratio data. Two-year mortality rates in relation to AdreView H/M ratio were < 1.2: 22.0%; 1.2-1.6: 11.5%; ≥1.6: 3.3%.2.

Heart failure is a persistent, progressive disorder in which the heart muscle is cannot pump adequate blood through the heart to meet the body’s needs. Patients who have earlier suffered from heart failure have a sudden death rate that is six to nine times greater than the general population.

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