Microbiologically documented nosocomial infections after coronary artery bypass surgery without cardiopulmonary bypass

ObjectiveThis study was undertaken to evaluate the frequency, characteristics, and risk factors of microbiologically documented nosocomial infections after off-pump coronary artery bypass grafting.MethodsA prospective cohort study was performed at Henry Dunant Hospital, Athens, Greece. It included all adult patients who underwent coronary artery bypass grafting with no valve surgery and without the use of cardiopulmonary bypass during a period of 3 years. Case patients were those with development of microbiologically documented nosocomial infections. Various variables were examined as possible risk factors for nosocomial infections.ResultsTwenty-one of 782 studied patients (2.7%) acquired 26 microbiologically documented nosocomial infections after off-pump coronary artery bypass grafting. Eight of 782 studied patients had pneumonia (1.02%), 7 of 782 (0.90%) had bacteremia, 4 of 782 (0.51%) had superficial wound infection at the sternotomy site, 4 of 782 (0.51%) had urinary tract infection, 2 of 782 (0.26%) had mediastinitis, and 1 of 782 (0.13%) had pressure sore infection. Twenty-one infections were monomicrobial, whereas 5 were polymicrobial. All polymicrobial infections were wound infections. There was a statistically significant difference in mortality between patients with and without nosocomial infection (23.8% vs 1.2%, P < .001). Clinical response of the infection to the treatment administered was observed in 21 of 26 episodes (80.8%) in 21 patients. A backward stepwise multivariable logistic regression model showed that independent risk factors (P < .05) associated with development of microbiologically documented nosocomial infection were arterial hypertension, previous vascular surgery, urgent operation, postoperative atrial fibrillation, number of inotropes used during and after operation, transfusion of fresh-frozen plasma during the intensive care unit stay, and intensive care unit stay until development of infection.ConclusionNosocomial infection after off-pump coronary artery bypass grafting is an uncommon but potentially life-threatening complication. The identification of independent risk factors, including arterial hypertension, associated with development of postoperative infection may help in the development of clinical strategies for the prevention, early diagnosis, and treatment of these infections.