Effect of anticoagulants on the incidence of late pericardial tamponade following open heart surgery. The Hawaii experience.

We report on 17 cases of late pericardial tamponade (LPT, > 60 hours postoperatively) occurring post aortic and/or mitral valve replacement or coronary artery bypass graft surgery between 1979 and 1994. This includes one patient in whom LPT occurred twice. These cases were found from a search of 374 patients including those who were diagnosed with hemorrhagic complications secondary to open heart surgery, pericardial effusion and tamponade, those who underwent pericardiocentesis and a randomly picked group of patients. The mean age of the group was 57.8 years and included 11 males and 6 females. Due to the relatively small size of our sample (reflecting the infrequency of this complication) we force matched this tamponade group to look for any relationships that may exist between the incidence of LPT and anticoagulant therapy. No significant difference was found between the two groups with documented preoperative anticoagulant therapy (number of days; p > 0.2) or in relation to coagulation tests (prothrombin time, partial thromboplastin time and platelet counts; p > 0.2). In our case series, anticoagulant therapy did not appear to significantly affect the incidence of LPT.