The FDA today released a recall notice for Penumbra‘s (NYSE:PEN) 3D Revascularization Device, part of its Penumbra system designed to remove thrombus from brain blood vessels during strokes, over issues with wire breaks and separations.

The FDA labeled the recall as Class I, its most serious designation, indicating that there is a reasonable probability that use of the product could cause serious adverse health consequences or death.

The 3D Revascularization device is designed to restore blood flow or remove blood clots in blood vessels in the brain during acute ischemic stroke in patients who are ineligible or fail intravenous tissue plasminogen activator therapy.

The company is recalling the devices due to a risk of the delivery wire breaking or separating during use. Fractured wire pieces could be left inside the patient’s brain bloodstream, and require attempts to retrieve the fractured pieces which could aggravate the stroke, according to the FDA recall notice.

The debris could also cause other serious adverse health consequences such as continued blockage of blood vessels, completion of the stroke or death, the agency warned.

A total of 155 units in the US are being recalled, with lot numbers C00644, C00645 and C00717, manufactured between March 31, 2017 and April 28, 2017 and distributed between May 15, 2017 and June 7, 2017.

The federal watchdog said that Penumbra had notified affected customers on June 9, instructing them to identify and remove any affected products and to arrange for a return and replacement.