The negative effect of internal mammary harvesting on sternal perfusion is well known, especially in diabetic subjects. Microdialysis previously showed increased lactate tissue concentration after mammary artery preparation. Although high antibiotic concentration is of utmost importance in this region, no study previously measured the effect of internal mammary artery harvesting on target tissue antibiotic concentration.

Study hypothesis:

Internal mammary artery harvesting imposes an additional risk for deep sternal wound infection by impairing antibiotic tissue penetration. This effect is mediated by altered perfusion patterns and may be seen in cephalosporin and/or Teicoplanin treatment.

Study objective:

To evaluate the impact of left internal mammary artery preparation on target tissue antibiotic concentration of Cefazolin and Teicoplanin during cardiac surgery

Design:

This study is designed as an observational pharmacokinetic trial. Patients are their own controls by measuring antibiotic concentration in different subcutaneous tissues.

Study population:

Patients referred for coronary artery bypass grafting to the Department of Cardiothoracic Surgery with planned unilateral left internal mammary artery preparation and a high risk profile for deep sternal wound infections will be asked to participate in this trial.

Inclusion Criteria:

• Written informed consent
• Planned coronary artery bypass grafting with unilateral internal mammary artery bypass
• Planned used of cardiopulmonary bypass

Exclusion Criteria:

• Inability to give informed consent
• Know allergy to cephalosporins, penicillin or Teicoplanin
• Re-operation
• Additional planned valve surgery
• Dialysis
• BMI > 30
• Long standing diabetes mellitus (> 7 years)
• Ejection fraction below 20% measured with transthoracic echocardiography
• Chronic severe renal insufficiency
• Childbearing potential

Patients referred for coronary artery bypass grafting to the Department of Cardiothoracic Surgery with planned unilateral left internal mammary artery preparation and a high risk profile for deep sternal wound infections will be asked to participate in this trial.