An Absorbable Antibacterial Envelope Promotes Development of a Healthy Device Pocket: Results of the TYRX Pocket Health Study

Introduction Creation of a pocket and implant of a cardiac implantable electronic device (CIED) elicits a foreign body response in the presence of the normal wound healing process. An absorbable antibacterial envelope (TYRX™, Medtronic Inc.) was developed to stabilize CIEDs and reduce infections. However, characterization of its impact on pocket healing is limited. We aimed to characterize histological and morphometric features of device capsules in patients previously implanted with an absorbable TYRX. Methods The TYRX Pocket Health Study (NCT05356546) was a prospective, observational study conducted from June 2022 to July 2023 at 9 sites. The study evaluated characteristics in existing CIED pockets of patients previously implanted with an absorbable TYRX returning for device replacement. Tissue sections were obtained, stained, and evaluated for adhesions, capsule thickness, inflammation, neovascularization, and calcification and compared to a historical control. Results The mean time between procedures was 6.8 years. TYRX pockets had significantly decreased adhesions ( p < 0.05) with no clinically significant calcification. TYRX capsules contained predominantly Type I collagen and were significantly thinner (0.33 ± 0.16 mm TYRX, 0.8 ± 0.3 mm controls, p < 0.0001). TYRX pockets had low inflammation with 96% of TYRX pockets (26/27) having absent to mild inflammation. Conclusion In this prospective evaluation of long‐term pocket healing with an absorbable TYRX, reduced adhesions, low inflammation, and well‐formed capsules were observed with no clinically significant calcification. This suggests that TYRX may promote creation of a well‐healed pocket desirable for subsequent procedures.