Establishment and Validation of an Animal Model of Abdominal Aortic Aneurysm in Beagles Through Vascular Patch Angioplasty and Elastase Infusion

  Objective   To evaluate the effect of an abdominal aortic aneurysm (AAA) animal model established in beagles by way of vascular patch angioplasty combined with elastase infusion.

  Methods  A total of 60 beagle dogs were included in this study. Among them, 10 beagles were assigned to a control group to obtain normal abdominal aortic wall tissue, while the other 50 underwent vascular patch angioplasty combined with elastase infusion in order to establish the AAA disease model. In order to evaluate the outcome of modeling, abdominal vascular ultrasonography was performed 14 days after the modeling surgery was performed and ultrasound and computed tomographic angiography (CTA) were performed 28 days after the modeling surgery. The criterion for evaluating modeling success is that the maximum diameter of the abdominal aortic aneurysm is 50% greater than the diameter of the normal abdominal aorta below the renal artery. A total of 20 beagles of the modelling group and 5 control beagles were sacrificed 35 days after the modeling surgery and infrarenal abdominal aortic wall tissues were harvested. Then, hematoxylin and eosin (H&E) staining, Masson's trichrome staining, and elastic van Gieson (EVG) staining were conducted to observe the pathology features of abdominal aortic wall tissues.

  Results  A total of 50 beagles underwent the AAA modeling procedures, with the average operative and anesthesia time being (119.4±18.9) and (137.4±15.8) minutes, respectively, the average blood loss volume being (43.6±7.7) mL, the average abdominal aorta block time being (39.7±5.3) minutes during the modeling surgery, and the average abdominal aorta diameter measured during the surgery being (6.5±0.4) mm. Intraoperative mortality was 0%. Mortality within 30 days after the surgery was 2% (1 out of the 50 beagles). Postoperative ultrasound and CTA results revealed that the success rate of AAA modeling was 100%. Pathology examination suggested that the animal model rather successfully simulated the pathophysiologic changes associated with human AAA in regard to the morphological and pathological changes.

  Conclusion  Vascular patch angioplasty combined with elastase infusion can be used to successfully establish AAA model in beagles. The AAA modeling method described in our report demonstrates stability and reliability in aneurysm formation effect and the surgical procedures are easy to replicate. The method integrates the advantages of previous animal modeling methods and can be used to study the pathogenesis of AAA.