Comparison of laser-assisted fibrinogen-bonded and sutured canine arteriovenous anastomoses

The effect of laser-assisted fibrinogen bonding (LAFB) on the development of intimal hyperplasia was studied with stress-strain profiles and histologic evaluation of canine arteriovenous fistulas (AVFs). In 19 animals femoral AVFs were created with an 808 nm diode laser after topical application of fibrinogen mixed with indocyanine green dye; in the contralateral limb a sutured AVF was created. The animals were divided into three groups. Group 1 dogs (n = 6) were killed serially up to 4 weeks after surgery to examine the healing of the anastomoses created with LAFB. Group 2 dogs (n = 6) were killed 1 month after surgery, and the fresh specimens were strained axially to produce a stress-strain profile graph. Group 3 dogs (n = 7) were killed 7 months after surgery, and the AVFs were infused with formalin under pressure and histologically prepared to allow comparison of the ratio of maximum to minimum intimal hypertrophy. Fibrinogen used for LAFB was resorbed during the first month after operation without evidence of foreign body reaction or inflammation. Tensile break force was not significantly different in the laser-bonded group (4.6 ± 2.4 pounds) and the sutured group (4.3 ± 1.7 pounds). The modulus (tensile break force per square inch), a measure of elasticity, identified the laser-bonded AVF (149 ± 44 pounds per square inch) to be less rigid than the sutured AVF (203 ± 35 pounds per square inch) (p < 0.05). No significant differences in the degree of intimal hyperplasia were noted in any area of the anastomoses. Use of LAFB neither accelerates nor prevents intimal hyperplasia in a canine AVF model. Although the higher modulus of sutured specimens predicts greater flow abnormalities, the clinical significance of these changes was not apparent.