It had told the company that it would seize product if the problems were not corrected, and that is what has happened. Apparently the most egregious offense is a poorly constructed and poorly maintained cleanroom.Shelhigh's products are tissue-based and are used in a number of high-risk surgical settings, which may have contributed to the agency's haste to take action. The products include pediatric heart valves and conduits, surgical patches, dural patches, annuloplasty rings, and arterial grafts. Among the applications for Shelhigh's products are open heart surgery in adults, children, and infants, and repair of soft tissue during neurosurgery and abdominal, pelvic, and thoracic surgery. Doctors are advised to use alternative products, and to monitor patients who already have Shelhigh implants.