Description

Abdominal Aortic Aneurysm (AAA) is a widespread disease with a high mortality rate in case of ruptures, with a sizable number of patients dying before a diagnosis is made. Approximately 32.000 patients are newly diagnosed with AAA and about 44.000 repair procedures are performed in the US every year. It is estimated that up to 2.000.000 subjects are living with an undiagnosed AAA with a greater incidence in the elderly population >65 years. Risk factors include smoking, hypertension, hypercholesterolemia, gender (men/women ratio 5:1) and family history (15-20%) increase risk amongst first degree relatives. The rupture risk increases with age and concomitant hypertension as well as current tobacco use and presence of other cardio-vascular diseases. AAA is clinically defined as a focal dilatation of the aorta causing a diameter increase of >50% of the expected normal diameter. Although any artery may develop an aneurysm, they are most commonly observed in the infrarenal abdominal aorta, thoracic aorta, popliteal artery and common iliac artery. The concomitants risks related to aneurysms are rupture and thrombus migration. Aneurysms slowly and continually grow in size leading to the aneurysm bursts. The larger an aneurysm becomes, the likelihood of eventual rupture may appear. The natural outcomes of aortic aneurysms is to enlarge and rupture. Other potential complications of the aneurysm include compression of adjacent organs which may result in aortoenteric fistula, or aortocaval fistula. If the thrombus embolizes and flows down the blood stream, this can induce acute or chronic arterial obliteration of the lower limbs.The risk of rupture is weighed against the risk of perioperative morbidity. The United Kingdom Small Aneurysm trial (UKSAT) reported 103 aneurysm ruptures in 2,257 subjects over a period of seven years, with an annual rupture rate of 2.2%. The decision to treat a patient that presents with an asymptomatic aneurysm is primarily dependent upon the size of the aneurysm. Current Society for Vascular Surgery (SVS) practice guidelines recommend surveillance for most subjects with a fusiform AAA in the range of 4.0 to 5.4cm in maximum diameter; therefore, surgical repair of abdominal aneurysms of 5.5 cm or greater in diameter is recommended in healthy subjects, as it is repair of saccular aneurysms. With the development of endovascular treatment options in recent years, treatment of AAA has become a viable option for patients with a high pre-operative risk. Endovascular Aneurysm Repair (EVAR) has become the treatment strategy of choice for AAA. Nowadays, the most important limit to the effectiveness of this technique is represented by complex anatomical situations, especially regarding the morphology of the proximal sealing zone. In previously published studies, the use of EVAR outside the specific instructions for use (IFU) of the devices for patients with challenging proximal aortic necks yielded a non-negligible rate of immediate complications and re-interventions. The Ovation iX and Alto endografts represent a new technical step in EVAR. This new device separates fixation from sealing: fixation is guaranteed by suprarenal stent and anchors, while sealing is ensured by inflatable rings filled with a low-viscosity, non-embolic, radiopaque fill polymer. This unique characteristic allows this graft to isolate aortic neck from blood pressure without radial force, with the result of very low ratios of Type 1 Endoleaks and absence aortic neck growing. The presence of the polymer-filled network also allows the graft to conform to the patient's aortic neck, providing precise and reliable sealing in a great variety of anatomies. Different from common stent-graft platforms, separation between fixation and sealing ensures that stent and fabric do not compete in the Ovation endograft for the same space within the shaft, and an ultra-low-profile delivery system can be achieved, allowing the treatment of patients presenting a wide range of iliac access.