The FDA has deemed the recall of the Medtronic (NYSE:MDT) Valiant Navion thoracic stent-graft system as Class I, the most serious kind.

Medtronic’s Valiant Navion is designed to repair lesions of the descending thoracic aorta. It uses a long catheter to place the stent graft inside the aorta. The stent graft expands to fit within the aorta to provide a new path for blood to flow from the heart to the lower part of the body, according to an FDA news release.

Medtronic initiated the recall on Feb. 4, 2021,  in response to information it obtained from the Valiant Evo global clinical trial indicating that three patients had experienced stent fractures. Two had confirmed type IIIb endoleaks.

At the time, a Medtronic spokesperson said that a secondary reintervention was performed to treat one patient’s type IIIb endoleak. Three days after the secondary procedure, the patient experienced hypotension and died. In the absence of an autopsy or explant, the death was reported as a probable aortic rupture and adjudicated by the trial’s independent clinical events committee as aneurysm-related mortality because it occurred within 30 days of the secondary procedure.

A total of 11 issues related to the device have been reported, including four cases of Type III endoleak, four cases of stent fracture and seven cases of stent ring enlargement. Some patients experienced multiple issues.

According to the FDA release, the devices under the recall were distributed between Nov. 12, 2018, and Feb. 10, 2021. So far, 14,237 devices have been recalled in the U.S.

Those affected by the recall are instructed to immediately cease use of the stent-graft system and follow instructions for returning unused products to Medtronic, then review all available images of patients treated with the system and contact Medtronic if they observe any issues.