UC San Diego

Post-operative pericardial adhesions pose a risk in cardiac resternotomies and may reduce cardiac function. 2-6% of reoperations result in catastrophic hemorrhaging, causing patient fatality in 39% of these cases (Duncan 1987, Dobell 1984). As resternotomies comprise 10% of cardiac surgeries, prevention of pericardial adhesions may reduce the likelihood of vascular injury and improve surgical visibility. The ultimate goal of this study was to evaluate the effectiveness of a sprayable aldehyde and aminooxy-functionalized poly(ethylene glycol) hydrogel as a barrier against post-operative pericardial adhesion formation. To accomplish this, a rodent model was developed after systematically altering surgical, animal, and material parameters in a series of pilot studies. Variables included subject gender, pericardium removal, length of study, abrasion method, and material concentration. Adhesions were evaluated visually after 2 to 6 weeks and gel retention examined at 1 and 3 days. A model of consistent and severe adhesion formation was developed and used to evaluate the hydrogel on a larger scale. 200 uL of the hydrogel or saline was sprayed onto the abraded epicardial region and allowed to crosslink for 15 minutes before closing. At two weeks, the mean adhesion score in the saline and treated groups was .57 ± .54 and .64 ± .44, respectively. Hematology, coagulation, and echocardiographic data showed almost no difference between the groups. While the hydrogel did not cause inflammation or impair cardiac function, the insignificant difference between the means of the two groups suggests that further work must be done to develop the animal model or improve the material.