Evaluation of post-operative development of mediastinitis in patients undergoing isolated coronary artery bypass grafting surgery: A single-center experience.

BACKGROUND

In this study, we aimed to evaluate mediastinitis cases developed after isolated coronary artery bypass graft surgery performed by median sternotomy to determine the causative microorganisms, risk factors, and clinical features.

METHODS

Between March 2009 and December 2018, a total of 44 patients (32 males and 12 females; mean age 62.84±6.951 years; range, 46-78 years) who underwent isolated coronary artery bypass grafting surgery with median sternotomy and developed mediastinitis postoperatively were included in the studying our cardiovascular surgery (CVS) department. Patients demographic information, comorbidities, habits, pre-operative hospital stay, elective or emergency surgery, perioperative internal mammary artery use, perioperative blood or blood product, operation and cardiopulmonary bypass times, suitability of antibiotic prophylaxis, medical and surgical treatment, clinical data, and laboratory results were retrospectively analyzed. Purulent discharge cultures obtained directly from the mediastinal space and microbiological examination notes made from the material obtained from the surgical site or surgical repair were recorded.

RESULTS

In isolated coronary artery bypass grafting surgery performed over a period of approximately 10 years, the rate of mediastinitis was 1%. There was no statistically significant difference between patients with and without mediastinitis in terms of age, sex, smoking habits, duration of operation and cardiopulmonary bypass, and intraoperative blood transfusion. The presence of diabetes mellitus and high mean body mass index was significantly higher in patients with mediastinitis compared to those without. Mediastinitis was diagnosed in 38 (86.3%) patients in the 1st month, 5 (11.3%) in the first 3 months, and 1 (2.2%) in the 1st year. Twenty-five (56.9%) Gram-positive bacteria, 13 (29.6%) Gram-negative bacteria, and 1 (2.3%) fungi were the microorganisms grown in purulent discharge cultures. Pathogen microorganisms could not be produced in 5 (11.4%) cases. The three most commonly isolated agents were methicillin-resistant coagulase-negative staphylococci (MRCNS) (50%), Escherichia coli (9.1%), and Klebsiella pneumoniae (6.8%).

CONCLUSION

Attention should be paid to surgical site infection in patients undergoing CVS. Following discharge, follow-up is important and empirical treatment should be determined by considering the presence of MRCNS as the leading infectious agent in our hospital when infection occurs.