Background and purpose: Infection is one of the most important complications after coronary artery bypass surgery. The purpose of this study was to evaluate the risk factors for infection in these patients.

Materials and methods: A descriptive prospective study was performed in 986 patients hospitalized in Sari Fatemeh Zahra hospital, Iran 2014-2015. Possible risk factors for infection (before, during and after the surgery) were recorded. Patients were followed up for possible infection until 30 days after surgery. Data was analyzed in SPSS applying t-test and Chi-Square. The p value less than .05 was considered significant.

Results: Totally, 52 patients (5.3%) developed infection including sepsis (28.8%), pneumonia (17.7%), mediastinitis (15.3%) and deep incisional surgical site infection (11.5%). Significant associations were found between developing infection following coronary artery bypass and prolonged use of Foley catheter, the balloon inside the artery during surgery, using internal mammary artery as a graft, left ventricular outputs, high blood pressure in the morning of surgery, days of hospitalization before and after the surgery, duration of intubation after surgery, duration of ICU stay, duration of bypass surgery, high BMI, and reoperation following complications (P> 0.05).

Conclusion: In this study, the risk factors during and after the surgery were more responsible for infection after coronary artery bypass surgery compared to preoperative conditions.