Effects of envelopes on cardiac implantable electronic device pocket healing: A head-to-head preclinical evaluation

BackgroundThe healing response to cardiac implantable electronic device (CIED) implantation results in inflammation that can result in fibrous pocket formation which may disrupt pocket healing or complicate future interventions.ObjectiveTo assess CIED pocket healing with use of the absorbable antibacterial TYRX™ envelope (T2), the next-generation (NG) TYRX absorbable antibacterial envelope under development, and the CanGaroo® extracellular matrix envelope (ECM) compared no envelope.MethodsA total of 110 CIEDs were implanted in an ovine model, either with (T2, NG, or ECM) or without envelopes. Histopathologic and morphometric analyses were completed at several timepoints after implant (3 days, 7 days, 4 weeks, 12 weeks, and 24 weeks). An independent pathologist completed a blinded histopathology assessment of the pockets.ResultsTYRX (T2/NG) pockets showed similar inflammatory and healing profiles to controls with more rapid provisional matrix formation compared to controls and ECM. ECM pockets exhibited increased acute (3 and 7 days) and chronic (24 weeks) inflammation. T2/NG had almost complete (T2) or complete (NG) absorption by week 12. ECM remained present at week 24 and was associated with significantly thicker capsules (ECM 0.80±0.14 mm, NG 0.37±0.10 mm, control 0.56±0.17 mm).ConclusionCompared to ECM, pockets with TYRX showed less inflammation, more rapid provisional matrix formation, faster absorption, and thinner capsules. TYRX pockets had low inflammation comparable to controls with accelerated provisional matrix deposition and tissue adhesion. The healing response to CIEDs used with TYRX fosters the formation of a well-healed pocket, which may bring patient benefit beyond its proven infection reduction.