Prevention of postoperative pericardial adhesions using tissue-protective solutions

Repeat cardiac surgical procedures are associated with increased technical difficulty and risk because of the previous formation of dense adhesions between the heart and the surrounding tissues. Dilute solutions of sodium hyaluronic acid (NaHA) and carboxymethyl cellulose (CMC) have been shown to prevent postoperative abdominal and pelvic adhesions and could therefore potentially inhibit adhesion formation following cardiac surgery. Adhesion prevention using 0.1% NaHA, 0.4% NaHA, or 0.1% CMC solutions was examined in a canine abrasion/desiccation pericardial adhesion model (5 animals/group) and compared to 10 animals treated with Ringer's lactate (RL) solution alone. The pericardium and heart were coated with 25 ml of test or control solution prior to and after pericardiotomy, after controlled gauze abrasion, after 30 min of desiccation, and prior to closure. At 6 weeks, animals were reexplored and adhesions were scored in a blinded manner by three to four surgeons using a 0-4 scale. Scores of 2 or greater were considered clinically significant. Mean adhesion scores from the left epicardium were 0.0 in animals treated with 0.1% NaHA, 0.6 in animals treated with 0.4% NaHA or 1% CMC, and 2.3 in animals treated with RL (P < 0.05 Duncan's ANOVA). In addition, none of the animals treated with 0.1% NaHA, 20% of the animals treated with 0.4% NaHA, and 20% of the animals treated with 1% CMC had clinically significant adhesions, whereas 80% of animals treated with RL had such adhesions. Sodium hyaluronic acid and CMC solutions, used as tissue coatings during cardiac surgery, inhibit the formation of undesired postoperative adhesions. Application of these biocompatible polymer solutions during surgery could reduce the technical difficulty and risk of repeat cardiac surgical procedures.