Staged Surgically Created Type B Aortic Dissection Model with Endovascular Re-intervention for Different Morphological Features.

Abstract

Understanding morphology and how this relates to treatment strategy is critical for achieving remodelling in aortic dissection. A controllable and reproducible large animal model is required for investigating new therapeutic devices and interventions. Our experimental protocol involved the development of surgically created type B aortic dissection (SC-TBAD) and endovascular reintervention-induced TBAD (ERI-TBAD) porcine models. The sample was randomly divided into two groups: one underwent a secondary tear creation (STC) procedure, and the other underwent a false lumen extension (FLE) procedure. Anatomical features were observed at 1 and 3 months, and 2 animals in each group were euthanized at 3 months after the procedures. The aorta and main branches were harvested en-bloc, cross-sectioned, and prepared for histological examination. All SC-TBAD models were successfully generated, and no unintended complications occurred. The ERI-TBAD model was successfully created in 11 of 12 animals, with 6 in the STC group and 5 in the FLE group. In the STC group, the intraoperative mean diameter of the new secondary tear was 7.23 mm, and a slight increase was observed at first 30 days (P = 0.0026). In the FLE group, the intraoperative new propagation length was (235.80 ± 84.94) mm. The FL propagation length at the one-month follow-up was significantly longer than that measured intraoperatively (P = 0.0362). Histological evaluation demonstrated that the elastic fibers in the media layer of the aortic wall were disrupted and appeared to be significantly stretched on the adventitial side of the false lumen. Our endovascular reintervention is a reliable, minimally invasive approach for producing specific TBAD models with different morphologies.