© 2018 European Society for Vascular Surgery Objective/Background: To evaluate the experimental feasibility of endovascular fenestration using specific endovascular scissor prototypes in an ovine model of acute aortic dissection (AD). Methods: A previously described endovascular technique was used to create a model of acute type B AD in sheep. Endovascular fenestrations using either endovascular scissor prototypes or a long sheath were compared. Four prototypes of endovascular fenestration scissors were evaluated. Both validity of the experimental model of AD and technical success of endovascular fenestration were assessed by haemodynamic criteria, completion angiography, transesophageal echocardiography, and post-procedural analysis of harvested aortas. Results: Experimental acute AD was created by endovascular means in 17 sheep, with a technical success rate of 82%. Systolic blood pressure was lower in the false lumen than in the true lumen (58 ± 5 vs. 79 ± 3 mmHg, respectively; p <.001). Endovascular fenestration was performed in 11 models (endovascular scissors n = 8; long sheath n = 3). Controlled endovascular fenestration was obtained by the use of endovascular scissors (n = 5/8), resulting in a significant rise in false lumen systolic blood pressure after fenestration (60 ± 2 vs. 67 ± 9 mmHg before and after fenestration, respectively; p <.047). Long sheath fenestration resulted in an uncontrolled flap motion, leading to either pseudo-coarctation syndrome or aortic rupture (58 ± 6 vs. 40 ± 2 mmHg before and after fenestration, respectively; p <.001). Conclusion: In this experimental study, a reproducible AD model has been developed in sheep using endovascular procedures exclusively to evaluate endovascular fenestration techniques. Endovascular fenestration using a long sheath appeared hazardous and risky in vivo. Endovascular scissors constitute a dedicated and suitable tool to perform a safe controlled and effective endovascular fenestration in an ovine model.