[Mediastinitis following coronary artery bypass graft surgery]

ABSTRACT

Mediastinitis is one of the ominous complications following cardiac surgery and has a higher degree of mortality. The aim of this study is to determine pre, intra and postoperative variables that predispose patients to mediastimitis. In this study, 27 pre, intra and postoperative variables were assessed. 1100 patients underwent coronary artery bypass surgery between June 1998 to 2000 and 35 [3.18%] patients developed mediastinitis [Group 1] who were compared with those who did not develop this complication [Group 2]. Mean age of Group 1 and 2 were 64.6 + 12 and 58.3 +14 years respectively. Group 1 comprised of 26 men and 9 women whereas Group 2 comprised of 788 men and 277 women. There was no meaningful difference as far as smoking, hypercholestremia or hypertension were concerned, however diabetes mellitus, obesity and chronic obstructive pulmonary diseases were much more common in Group 1 [p<0.05]. Majority of the patients in Group 1 compared to Group 2 were in class 3 and 4 based on New York Heart Associations severity of heart failure [p<0.05]. Both left and right internal mammary artery grafts were used in 14.2% of Group 1 and 8.9% of Group 2 patients [p<0.01]. 342% of Group 1 and 7.1% of Group 2 patients underwent re-operation because of hemorrhage. The need for mechanical ventilator for more than 24 hours was observed in 7[20%] and 91[81.5%] of Group 1 and 2 respectively. Multivariate analysis demonstrated that 4 out of the 27 variables had a crucial effect in the development of mediastimitis and these veriables included obesity, severity of heart failure, length of operation time, and re-operation. Postopertive one-month mortality was 14% and 4.6% respectively in Groups 1 and 2.The study documents that obesity, prolonged operative time, severity of heart failure, and reoperation are the most important predisposing factors in mediastinitis following coronary artery bypass graft surgery