The sheep as a model for coronary artery bypass surgery

Area of Science:

• Cardiovascular Surgery
• Animal Models
• Surgical Innovation

Background:

• Sheep possess anatomical similarities to humans, making them suitable for cardiovascular surgery research.
• Previous sheep models faced challenges including high infection rates from median sternotomy and susceptibility to ventricular fibrillation (VF) and myocardial ischemia.
• These limitations hindered the widespread use of sheep in complex cardiovascular procedures.

Purpose of the Study:

• To evaluate the efficacy of a novel sutureless anastomotic device for coronary artery bypass surgery in a sheep model.
• To address and overcome the limitations previously associated with using sheep for cardiovascular surgery research.
• To establish a safe and effective sheep model for coronary artery surgery.

Main Methods:

• Fifty-seven adult female sheep underwent coronary artery bypass surgery using a new anastomotic device.
• The surgical approach was modified from median sternotomy to left lateral thoracotomy (LLT) to mitigate infection risks.
• Prophylactic anti-arrhythmic drugs, normothermia, and myocardial preconditioning were employed to minimize cardiac vulnerability.

Main Results:

• The left lateral thoracotomy approach successfully resolved issues with infected median sternotomy incisions.
• Aggressive prophylactic measures significantly reduced cardiac vulnerability to manipulation and ischemia.
• The mortality rate in the sheep model decreased from a prohibitive 45% to 0% (P <0.0001).

Conclusions:

• The sheep model can be effectively and safely utilized for coronary artery surgery research.
• Specific surgical techniques, including the LLT approach, and pharmaceutical interventions are crucial for success.
• This study demonstrates a reproducible and safe method for sheep-based cardiovascular surgical research.