Indirect myocardial revascularization--an experimental study in the dog

Area of Science:

• Cardiovascular Surgery
• Regenerative Medicine
• Myocardial Revascularization

Background:

• Previous studies indicate skeletal muscle flap grafting can achieve myocardial revascularization.
• The functional capacity of neovessels formed by this grafting technique requires further evaluation.

Purpose of the Study:

• To assess the functional significance of neovessels created by grafting a free skeletal muscle flap onto the canine heart.
• To evaluate regional myocardial blood flow under conditions of coronary artery occlusion and collateral flow enhancement.

Main Methods:

• Five dogs underwent LAD (left anterior descending coronary artery) Ameroid constrictor implantation and simultaneous free muscle flap grafting.
• Arterial anastomosis was performed using the internal mammary artery, with venous drainage into the right atrium.
• Regional myocardial blood flow was measured using the radioactive microsphere technique under various coronary occlusion scenarios, including "preconditioning".

Main Results:

• Despite complete LAD occlusion, antero-lateral myocardial blood flow remained unchanged, indicating functional revascularization from the graft.
• Blood flow in the circumflex artery (CX) territory was minimal during occlusion.
• "Preconditioning" improved perfusion in the epicardial regions supplied by the CX.
• Histological examination revealed large sinusoid-like blood conductors connecting the graft to the heart.

Conclusions:

• Grafting a free skeletal muscle flap onto the canine heart successfully establishes functional myocardial revascularization.
• The neovessels formed are capable of sustaining regional myocardial blood flow during coronary artery occlusion.
• This technique holds promise for treating ischemic heart disease.