Controllable and Uncontrollable Stanford Type B Aortic Dissection in Canine Models

Abstract

Background/Aims: Stanford type A and type B aortic dissections are anatomically distinct. Few animal models appropriately mimic human aortic dissection in the clinical setting. We developed animal models that mimicked uncontrollable Stanford type B aortic dissection as well as controllable dissection. Methods: Twelve female beagle dogs were randomly assigned to the uncontrollable dissection model, and 8 to the controllable. After creation of the false lumen using a self-made separator, epinephrine was injected acutely in the uncontrollable model, and a rapid injection of saline expanded the false lumen in the controllable model using a balloon catheter. Results: All models mimicked Stanford type B dissection at autopsy. Dissections formed in 9 of the 12 animals of the uncontrollable model as confirmed by digital subtraction angiography (DSA) performed 1 week after surgery. For the controllable dissection model, 6 out of 8 animals survived, and dissection was confirmed by DSA. Occlusion of the dissection developed 4 weeks after surgery in all 6 cases. Conclusions: We have developed an easy, stable animal model of Stanford type B dissection which provides a great length of false lumen and appears very similar to aortic dissection in humans.

Endovascular creation of aortic dissection in a swine model with technical considerations

“…9-20 These models, however, have had certain disadvantages. Thoracotomy and/or laparotomy are usually necessary to create an aortic dissection model [9][10][11][12][13][14][15][16][17][18][19][20] ; however, such invasive surgical procedures are not suitable for use as dissection models for medical treatment. In our model, only endovascular procedures were used, and neither thoracotomy nor laparotomy was required.…”

“…22 Furthermore, small animals such as canines are not suitable for carrying out experiments involving endovascular therapy due to small aortic size. [9][10][11][12][13][14][15]18,20 We used swine with a mean aortic diameter of 10.9 Ϯ 2.9 mm; thus, swine should be considered a suitable model for future studies using endografts.…”

“…Among the surgical attempts used for animal models, [9][10][11][12][13][14][15][16][17][18][19][20] various techniques have been used to create an initial dissection at the proximal site, including elastase infusion, 19 normal saline infusion, 17,20 using an endarterectomy spatula, [10][11][12]14 hand rubbing the initial dissected site to widen the tear, 16 balloon dilatation combined with solution infusion, 18 and increasing the blood pressure after surgery. 10,13 With respect to creating the initial dissection, we developed a new and attractive technique using a modified 10F outer sheath with a 14 G stiffening metallic cannula of the Rösche-Uchida Transjugular Liver Access Set.…”

“…[10][11][12][13][14][15][16]18,20 In our model, however, blunt retrograde desquamation by the loop formation of the .035-inch guidewire facilitated easy extension into the long length of the dissected space. In fact, far more dissected length was obtained in our model than in other similar models.…”

“…There have been several attempts to create aortic dissection models in animals with surgical procedures; these have certainly contributed to the development of advanced therapies. [9][10][11][12][13][14][15][16][17][18][19][20] However, surgical models have had limitations in the sense of its invasiveness. Another disadvantage is that creating the primary tear from the outer side of the aorta clearly differs from the spontaneous aortic dissection mechanism that occurs from the inner lumen.…”