CardioGen-82 to re-enter U.S. market, with boxed warning

Nuclear stress test ordering is one of multiple gender disparities in cardiac imaging. Source: Miriam Hospital, Providence, R.I.

The FDA is notifying healthcare professionals, and in particular, the medical imaging community, about the planned return of CardioGen-82 to the U.S. market following the voluntary recall by the manufacturer, Bracco Diagnostics, on July 25, 2011. The agency has approved revised labeling for CardioGen-82 to include a boxed warning and enhanced testing information to help minimize the risk for exposure to unintended levels of strontium radiation.

CardioGen-82 consists of a generator that is used at clinical sites to produce rubidium (Rb)-82 chloride injection. Tests for strontium and rubidium radioactivity are performed upon the fluid, or eluate, obtained from the generator.

The revised labeling, according to the FDA, establishes new Alert Limits for strontium-82 (Sr-82) and strontium-85 (Sr-85) levels in the generator eluate. If the eluate reaches these Alert Limits, then additional Sr-82 and Sr-85 eluate testing is required.

Previously, eluate testing was done only once a day; with the revised labeling, the testing is completed daily, but additional tests are performed that day if a generator eluate has reached the Alert Limit, the agency explained. The additional daily testing is necessary to promptly identify excess strontium levels which indicate that the generator expiration is approaching. The revised labeling also includes new information to identify when a generator is expired and its use must stop.

"To minimize the risk of increased radiation exposure in patients, clinical sites should strictly follow the new directions for use of the CardioGen-82 generator in the labeling," the FDA said. Clinical sites and healthcare professionals can access the most updated CardioGen-82 labeling.

Clinical sites are also reminded to review and update the instructions for their dose calibrators to ensure proper isotope readings are performed in the eluate testing procedures. In January, the FDA said that certain clinical sites are responsible for the exposure of some patients to more radiation than is typically associated with a CardioGen-82 scan.