Endovascular aneurysm repair (EVAR) is a type of minimally-invasive endovascular surgery used to treat pathology of the aorta, most commonly an abdominal aortic aneurysm (AAA). When used to treat thoracic aortic disease, the procedure is then specifically termed TEVAR for "thoracic endovascular aortic/aneurysm repair." EVAR involves the placement of an expandable stent graft within the aorta to treat aortic disease without operating directly on the aorta. In 2003, EVAR surpassed open aortic surgery as the most common technique for repair of AAA,[1] and in 2010, EVAR accounted for 78% of all intact AAA repair in the United States.[2]
Standard EVAR is appropriate for aneurysms that begin below the renal arteries, where there exists an adequate length of normal aorta (the "proximal aortic neck") for reliable attachment of the endograft without leakage of blood around the device ("endoleak").[3] If the proximal aortic neck is also involved with the aneurysm, the patient may be a candidate for complex visceral EVAR with a fenestrated or branched EVAR.
Patients with aneurysms require elective repair of their aneurysm when it reaches a diameter large enough (typically greater than 5.5 cm) such that the risk of rupture is greater than the risk of surgery. Repair is also warranted for aneurysms that rapidly enlarge or those that have been the source of emboli (debris from the aneurysm that dislodges and travel into other arteries). Lastly, the repair is also indicated for aneurysms that are the source of pain and tenderness, which may indicate impending rupture. The options for repair include traditional open aortic surgery or endovascular repair.[citation needed]
Endovascular procedures aim to reduce the morbidity and mortality of treating arterial disease in a patient population that is increasingly older and less fit than when major open repairs were developed and popularized. Even in the early days, significant risks were accepted in the understanding that the large open operation was the only option. That is not the case in most patients today.[citation needed]
Studies that assign aneurysm patients to treatment with EVAR or traditional open surgery have demonstrated fewer early complications with the minimally invasive approach. Some studies have also observed a lower mortality rate with EVAR.[4][5] The reduction in death, however, does not persist long-term. After a few years, the survival after repair is similar to EVAR or open surgery. This observation may be the result of durability problems with early endograft, with a corresponding need for additional procedures to repair endoleaks and other device-related issues. Newer, improved technology may reduce the need for such secondary procedures. If so, the results of EVAR may improve to the point where long-term survival benefit becomes evident.[citation needed]
EVAR is also used for rupture of the abdominal and descending thoracic aorta, and in rare cases used to treat pathology of the ascending aorta.[6]