PERICARDIAL TRAUMA AND ADHESIONS IN RELATION TO REOPERATIVE CARDIAC-SURGERY

In an attempt to appreciate the changes that favour adhesion formation we compared the morphological and fibrinolytic changes that occur in human primary and reoperative pericardium. Ten patients undergoing pri mary elective open heart surgery and ten undergoing first time reopera tive open heart surgery were studied. Pericardial samples were taken a t four time points. At 0 (time A) and 30 (time B) minutes from the tim e of pericardiotomy (before the commencement of CPB), 30-50 minutes (t ime C) after the commencement of CPB, and then finally 10 minutes (tim e D) after the patient had been rewarmed. The fibrinolytic activity, a s measured by the plasminogen activating activity (PAA), in the perica rdial samples of the ten primary cases was compared with that in 5 of the reoperative cases. For the primary group, the PAA after 30 minutes of exposure (median 6.65 IU/cm(2), range 3.85-11.89 IU/cm(2), p=0.14, n=10) was not significantly reduced when compared to the initial acti vity (median 8.74 IU/cm(2), range 2.22-17.68 IU/cm(2), n=10). After 30 -50 minutes CPB the PAA was significantly reduced (median 3.93 IU/cm(2 ), range 1.5-13.24 IU/cm(2), p=0.028, n=10) and still reduced after re warming for 10 minutes (median 3.12 IU/cm(2), range 0.88-19.93 IU/cm(2 ), P=0.047, n=10). The simultaneous plasma tissue-type plasminogen act ivator activity showed a significant (p<0.05) increase after 30-50 min utes bypass with a later decline. The changes in the reoperative peric ardial PAA were similar. in addition, the degree of PAA in reoperative pericardium was consistently lower than that observed in primary tiss ue. The extent of primary pericardial mesothelial damage at times B, C , and D compared with that at time A showed a significant (P<0.01 for times B, C, and D) increase. Similarly there was a significant worseni ng of the degree of inflammation . Compared with primary pericardium, the reoperative samples showed a significant (p<0.01 for times A, B, a nd C) preponderance of damaged mesothelium at the earlier stages of th e oepration. It appears that, following the initial bypass surgery, th e processes that cause pericardial and mesothelial healing with recove ry of PAA compete with those leading to pericardial adhesions and fibr osis. The histological and biochemical outcome seen in reoperative per icardium is the result of these competitive actions.