In vivo microvascular freezing in veins: experimental study

Area of Science:

• Vascular surgery
• Regenerative medicine
• Surgical techniques

Background:

• In vivo freezing of microarteries effectively relieves spasm without causing thrombosis.
• The application of vascular freezing in veins remains less understood, particularly regarding its long-term effects and graft viability.

Purpose of the Study:

• To investigate the effects of in vivo vascular freezing on rat veins using ethyl chloride.
• To evaluate the patency rates and pathological changes in frozen veins after division and anastomosis.
• To determine the feasibility of using frozen veins as grafts in different vascular beds.

Main Methods:

• Two experiments were conducted on rat epigastric and femoral veins using ethyl chloride freezing.
• Experiment 1 assessed immediate diameter changes, patency rates at 2, 10, and 30 days, and pathological findings.
• Experiment 2 evaluated patency rates at 72 hours after freezing, dividing, and anastomosing the veins.

Main Results:

• Frozen veins demonstrated 100% patency initially, with significant increases in diameter and evidence of progressive regeneration of intima and media layers.
• In experiment 2, femoral vein grafts achieved 100% patency at 72 hours, whereas epigastric vein grafts had only 5% patency.
• Microthrombi were observed in all specimens, and pathological findings included loss of intima and media layers with subsequent cellular regeneration.

Conclusions:

• Vascular freezing of microveins can relieve spasm without inducing thrombosis and allows for vein regeneration.
• Frozen femoral veins are suitable for division and anastomosis, yielding high patency rates.
• Frozen epigastric veins are less suitable for anastomosis, likely due to differences in diameter and blood flow compared to femoral veins.