麻豆传媒

CHICAGO -- The radiotracer may be a new tool for cardiac imaging, but whether it's ready for routine use in most practices was debated by nuclear cardiologists here.

The tracer, also known as iobenguane (AdreView), got the FDA's green light for earlier this year. The compound accumulates in innervated tissues, highlighting any areas of lost nerve supply.

While there are other tracers and other imaging techniques to highlight blood supply or muscle in the heart, "it looks at something unique, something no other noninvasive imaging or invasive imaging can look at," , explained at a debate here at the American Society of Nuclear Cardiology meeting, where he argued that mIBG is poised to enter mainstream practice.

In nuclear cardiology, studies have shown volume of denervated myocardium imaged with mIBG to be a much better predictor of outcomes in heart failure, with about a 15% reclassification advantage, noted Travin, director of cardiovascular nuclear medicine at Montefiore Medical Center in New York City.

"The hope is this test would identify heart failure patients at very low risk and to not have to put them through having a defibrillator," which carries risk of unnecessary shocks and infection along with substantial expense, , of St. Luke's Mid America Heart Institute in Kansas City, Mo., told 麻豆传媒.

"We're almost there in terms of the science," he said. He spoke at the conference about the business end of adopting the new tracer.

However, "almost there" isn't going to be good enough for many clinicians, suggested , cardiology director and chief of the nuclear cardiology laboratory at Tufts Medical Center in Boston, who took the con side in the debate.

"There's some prognostic value, but if the measurement -- the heart-mediastinum ratio -- is high, will I really not put in a defibrillator because that person is at such low risk? The data are simply not strong enough," he told 麻豆传媒.

The ADMIRE-HF trial, which formed the basis for FDA approval for this indication, only showed that the ratio was a significant independent predictor of arrhythmic and cardiovascular events in heart failure patients. The trial didn't test the score in patient management decisions.

"Down the line, if the right studies are done to show that it really could be potentially safe, if someone is at such low risk, to not put in a defibrillator in concert with ongoing payment reform that gives us just a chunk of money to take care of heart failure patients -- I'm happy not to put one in if I know it's safe and I'm incentivized to not do things -- in the future, all those streams could come together and make it really useful," Udelson explained. "But right this second, no."

Thompson agreed that the test is promising but is going to take some time for adoption.

"Heart failure doctors and electrophysiology doctors aren't very enthusiastic about it because they don't know much about it yet," he said, though predicting "it's probably going to be a useful tool."

Another key hurdle is reimbursement. The Centers for Medicare and Medicaid Services (CMS) has given mIBG imaging an "emerging technology" billing code reimbursed at roughly $300, whereas the tracer costs anywhere from $2,200 to $3,900 depending on the type of price quoted.

"It doesn't even cover nearly the cost of the isotope, so providers are taking a hit," Udelson noted. "That's a bit of a nonstarter."

That situation may change in the near future, Thompson said, but for now billing for the test takes extra work.

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