“A ruptured AAA [Abdominal Aortic Aneurysm] is the 15th leading cause of death in the country, and the 10th leading cause of death in men older than 55” in the United States, states Singh (n.d.), in the Society for Vascular Surgeons. Such Abdominal Aortic Aneurysms (AAA, see Figure 2.2) are increasingly treated by endovascular surgery, during which stent grafts are placed in the ballooned vessel through access sites such as the femoral (thigh) arteries, a procedure called Endo Vascular Aneurysm Repair (EVAR). 10% of patients has an aneurysm near significant arteries (Mayo Clinic, 2019), called a complex AAA, requiring stent grafts fitted with fenestrations (FEVAR, see Figure 2.1) or side branches (BEVAR).   After puncture of the femoral artery, an introducer sheath is placed in the vessel, functioning as a re-usable access point to the arterial system. The sheath prevents blood from flowing out of the artery and enables entrance of tools such as guide wires, catheters and smaller sheaths into the arteries. However, treatment of complex AAA requires introduction of multiple tools (up to 5) through the sheath simultaneously, compared to just one or two during EVAR. With every additional tool being introduced, the valve’s capability of adequate closure is reduced even more. This results in leakage that can lead to significant blood loss for the patient.   The Pentaport is a new, safe gateway for complex endovascular aortic repair (Figure 2.3). It functions as an add-on for commonly used sheath models. A leakproof ‘plug & screw’ connection facilitates safe and easy fastening to large-bore introducer sheaths. The Pentaport minimises blood leakage. Preventing severe blood losses of 2L or even more during one surgery, spares a heavy attack on the patient’s condition and eliminates the need for costly consequences, such as cell-saving or blood transfusion. In addition, it prevents the need for lengthy recatheterisation efforts (up to 60 minutes) and possible harm to the patient’s arteries. The design was evaluated and proof of concept was achieved, through functionality tests in simulated environments and usability tests with medical specialists.