Prevention of Postoperative Pericardial Adhesions: An Animal Study

Following heart operations, adhesions uniformly form between the epicardium and surrounding structures such as the pericardium, mediastinal fat, pleura, and sternum. These adhesions make reoperations both difficult and hazardous. Three groups of 15 dogs each were studied to assess the effectiveness of pharmacologic manipulation in reducing the adhesions. In the control group, adhesions were created by allowing epicardial/pericardial surfaces to dry, and then adding cotton fibers and blood before closing the pericardium. In the methylprednisolone group, 500 mg of methylprednisolone was given intravenously at the time of operation, followed by 0.3 mg/kg orally three times a day for one week. In the ibuprofen group, 12.5 mg/kg of ibuprofen was given intravenously at operation and then orally three times in one day, followed by 5 mg/kg orally three times a day for six days. Dogs were killed at three to four weeks and the adhesions between pericardium and epicardium were graded. In the control group, none were adhesion-free and none had filmy adhesions; three dogs had dense patchy adhesions and 12 had dense diffuse adhesions. In the methylprednisolone group, 14 dogs had no adhesions; one had filmy adhesions; and none had dense patchy or dense diffuse adhesions. In the ibuprofen group, none were adhesion-free; one dog had filmy adhesions; four had dense patchy adhesions; and ten had dense diffuse adhesions. The near-total elimination of pericardial/epicardial adhesions utilizing methylprednisolone, if also achievable in humans, would markedly reduce the difficulty and increase the safety of cardiac reoperations.