Innovative Sternal Closure Techniques: Evaluating STRATAFIX™ and DERMABOND™ for Reduced Complications in CABG Patients

Cardiovascular disease (CVD) represents a major burden of morbidity and mortality. Approximately 8.5% of Canadian adults live with CVD and it is the second leading cause of death in Canada. In Canada, over 30,000 cardiac surgical procedures are performed each year, the vast majority via a sternotomy. Sternotomy complications can be life-threatening especially when they beget sternal dehiscence (SD) and deep sternal wound infection (DSWI). It is often unclear whether SD caused SWI or vice versa. Superficial sternotomy complications have a 5-10% occurrence, with DSWIs occurring in 0.2-5% of patients. When sternal complications do occur, patient-reported outcomes are impacted and mortality rates can be as high as 10-30%.

Typically a combination of steel wires and synthetic, absorbable sutures are used to close sternal incisions. Recently, the development of barbed sutures have been shown to reduce knot slippage and complications related to knot tying. Insufficient data on their feasibility and safety in cardiac surgery has limited their use in the field. Furthermore, research has demonstrated the benefits of otherskin closure systems, that combines 2-octyl cyanoacrylate with a self-adhesive polymer mesh tape, but their effects have been minimally investigated on sternal wound closures (SWCs). Moreover, the combinatory effects of barbed sutures and mesh-based antibiotic skin adhesives on SWCs have not been investigated.

Surgical site infections (SSIs) in CABG are often sternal wound infections which are classified as deep sternal wound infection (DSWI) and superficial sternal wound infection (SSWI). DSWIs, also known as mediastinitis, have an incidence of 1-5% and are associated with the highest SWI mortality rates ranging between 10-47%. Mediastinitis is the inflammation of the tissue and organs within the mediastinum (an area in the chest that contains vital organs such as the heart, trachea, and esophagus). In contrast, SSWIs have a slightly higher incidence of 0.5-10%, with a much lower mortality rate of 0.5-5%, and affect the skin, subcutaneous tissue, and pectoralis fascia. Considering DSWI can affect highly protected organs in the mediastinum, it is predicted that DSWI usually occurs due to preoperative contamination, meanwhile, SSWI is a more superficial infection and is hypothesized to begin on the epidermis and move inside, through the tissue layers. Importantly, DSWI and SSWI share similar risk factors such as diabetes, pre- and post-operative complications, and obesity.

The goal of the study is to determine if implementing a combination of barbed sutures (STRATAFIX™) and a mesh-based topical skin adhesive (DERMABOND™ PRINEO™ ) on sternal wound closures will reduce the incidence of sternal complications, such as sternal dehiscence and sternal wound infection, in patients undergoing coronary artery bypass grafting (CABG) surgery. The investigators hypothesize that this combined approach will significantly reduce sternal dehiscence and wound infections, leading to a measurable decrease in patient morbidity and mortality.

The primary objective of this study is to assess whether the use of STRATAFIX™ barbed sutures, featuring antibacterial triclosan coating, and DERMABOND™ PRINEO™ wound closure system which combines 2-octyl cyanoacrylate with a polymer mesh will reduce sternal wound closure complications in CABG patients over a period of 6-weeks. The secondary objectives are to compare the cost-effectiveness for the hospital and quality of life in patients who have received this novel approach for sternal wound closure, versus the customary materials (i.e., non-barbed, no mesh-based antibiotic skin adhesives) used by cardiac surgeons.

The primary outcomes will include the following:

1\) The incidence of DSWI, SSWI, SSI, and SD.

1. Sternal wound sites will be classified based on a blinded grading using the Centers for Disease Control and Prevention 4-level classification system13. 2. The cardiac surgeon will perform a visual assessment to determine the presence of SD, recording the outcome as a binary result (yes or no).

The secondary outcomes will include the following: 1. Quality of Life Assessment (QALY) will be completed using the EQ-5D questionnaire which measures mobility, self-care, usual activities, pain/discomfort, and anxiety/depression14. The questionnaire will be distributed for completion at the 6-week post-operative visit. 2. Should SD occur, its severity will be measured using a gap measurement. 3) All-cause mortality.

4\) Incidence of ST- and non-ST-elevation myocardial infarction (STEMI and NSTEMI, respectively).

2 5) Utilization of hospital resources, specifically, the frequency of hospital readmission, length of stay at the hospital, and number of revisions and/or reoperations for sternal closure due to infection or dehiscence.

6\) Antibiotic dosage and frequency. 7) Aesthetic assessment of the sternal closure site. 8) Cost-effectiveness of the materials used will be analyzed related to the EQ-5D questionnaire responses.