The question this research project wants to explore is whether using the Prevena Incision Management System (Prevena) will improve sternal wound edge oxygenation in patients undergoing Coronary Artery bypass surgery with Bilateral Internal Mammary Artery grafts.

Coronary artery bypass is the gold standard surgical treatment of patients with complex coronary disease. It is a common operation and more than 16000 procedures per year are carried out in the UK. Recent publications suggest that during the bypass procedure both left and right internal mammary arteries should be used to bypass coronary stenoses. It was noted that using both internal mammary arteries will result in even better long term survival with improved freedom from cardiac events such as myocardial infarction or further coronary intervention than using. The major drawback of using both internal mammary arteries is the increased risk of sternal wound infection and breakdown. The investigators will use Near Infra-Red Spectroscopy (NIRS) to assess the wound edge oxygenation delivery. The NIRS INVOS system the investigators use within Sheffield Teaching Hospitals can measure oxygenation of soft tissue to a certain depth making it suitable for the assessment of wound edge oxygen delivery. Prevena is commercially available and has a CE mark.

The Prevena wound management system differs from conventional wound dressings, it applies negative pressure to the closed wound for 7 days. Wound complications/infections are decreased when this type of wound management system is used. Studies suggest that Prevena achieves these outcomes because of an increase of perfusion in the wound edges and keeping the wound dry. Patients will be randomised to either the Prevena wound management or their standard of care NHS wound management for their procedure. The oxygenation and outcomes of the wounds will be compared through data collection and the patients followed up during their routine inpatient care and 6 week outpatient appointment.

Inclusion Criteria:

• Eligible patients are those who require isolated coronary artery bypass surgery, who need at least 2 bypass grafts, and who are deemed suitable by the operating surgeon to have both right and left internal mammary arteries harvested as conduits

Exclusion Criteria:

• Require additional procedures in addition to the coronary bypass or need for internal mammary artery harvest for feasibility study
• Who are deemed by the operating surgeon as unsuitable for bilateral internal mammary artery harvest because of
• Age (75 or older where prognostic benefit of using both internal mammary arteries has been questioned),
• Obesity with a BMI which is higher than 35 (increased risks of wound infection)
• Diabetes (of any type) (increased risks of infection.)