Reduction of post-surgical pericardial adhesions using a pig model

Background: Post-surgical pericardial adhesions pose an increased risk of complications during redo sternotomies. Adhesive tissue formation is a normal response to tissue injury and involves complex patho-physiological processes including the actions of prostaglandins to cause plasma leakage and fibrin formation. The purpose of this study was to assess the ability of two non-steroidal anti-inflammatory agents (Indomethacin and Rofecoxib) and a barrier (Coseal, a polyethylene glycol) to limit adhesion formation following cardiac surgery in a pig model. Methods: Forty-four piglets were allocated equally to four treatment groups: Group 1: Control, Group 2: intramuscular Indomethacin, Group 3: oral Rofecoxib and Group 4: Coseal sprayed on the heart. A full median sternotomy was performed on each animal and the heart exposed. Adhesions were induced by rubbing tissues with gauze, applying sutures and leaving blood in the pericardial sac before chest closure. Plasma inflammatory markers including prostaglandin E2 and thromboxane B2 were measured preoperatively and on Days 2, 5 and 10 after surgery. Eight animals from each group were slaughtered after 12 weeks and 3 after 25 weeks. Adhesions were assessed macroscopically and microscopically. Results: Compared to the Control group, the extent of adhesions was significantly less in all other groups whilst adhesion density was least in the Indomethacin and Coseal groups. Indomethacin and less so Rofecoxib, inhibited the synthesis of prostaglandin E2 and thromboxane B2 but there were no significant changes in other inflammatory markers. Conclusions: We conclude that systemic Indomethacin, and locally applied Coseal are suitable methods to markedly reduce pericardial and retrosternal adhesions.