RAA represent a relatively rare condition, with an incidence of approximately 0.09% in the general population. The majority are asymptomatic, and therefore found incidentally. Peak incidence is in patients 40 to 60 years of age, and they are slightly more prevalent in women.

As with aortic disease, the vast majority of RAA are associated with atherosclerotic disease. Degenerative processes such as fibromuscular dysplasia, various arteritides, and connective tissue disorders such as Ehlers–Danlos syndrome have also been implicated in this disease.

Approximately 75% of RAA are saccular. They are more prevalent on the right, with approximately 10% of patients demonstrating bilateral disease. They are most commonly located at or just beyond the bifurcation of the main renal artery, in the secondary artery branches. This location contributes to the complexity of operative repair. Intraparenchymal aneurysms are rare, occurring in less than 10% of cases.

The indications for operative intervention for RAA include management or prevention of rupture, uncontrolled hypertension, acute dissection, and clinical symptoms.

RAA rupture is rare, occurring in less than 3% of patients. However, in most series the mortality of aneurysm rupture is approximately 10%. This is much higher in pregnant women, with mortality rates as high as 50%. RAA rupture is an indication for emergent intervention. Similarly, any patient who exhibits symptoms associated with an RAA, generally manifested as abdominal or flank pain, should be offered repair as these are often signs of impending rupture.

Elective repair in order to prevent rupture is a much more common indication; however, this remains somewhat controversial. Since most RAA are asymptomatic and discovered incidentally, the natural history is unclear. Aneurysm size as it relates to risk of rupture is not as well-defined as it is for abdominal aortic aneurysms. It has generally been accepted that asymptomatic RAA greater than 2 cm in diameter should be considered for repair. The presence of calcification of the aneurysm has also been studied, and was at one time thought to be protective against rupture. As with size however, most series have shown no definitive evidence of this, and the presence or absence of calcification should not be considered when evaluating for elective repair.

As previously stated, pregnant women are considered to be at higher risk for rupture of RAA than the rest of the population. In cases of rupture, many studies have quoted maternal mortality of approximately 50%, with fetal mortality reaching nearly 75%. For this reason, women of child bearing age with intended future pregnancies should also be considered for elective repair. Women who are already pregnant, or who are symptomatic should undergo repair. The operative risk as it relates to maternal and fetal safety should be assessed as with any other surgical intervention. It is safest to delay operative repair until the third trimester, if possible.

Renovascular hypertension associated with RAA is still somewhat poorly understood. Many theories exist for this connection. These include distal embolization with injury to the kidney parenchyma, kinking or compression of arterial branches due to mass effect, and turbulent flow within the aneurysm causing decreased renal perfusion. Most series of patients with hypertension associated with RAA have shown improvement after repair. Some results have shown as many as 75% of patients demonstrated better blood pressure control. In any case, patients who have hypertension which is difficult to control in the setting of RAA should be evaluated for repair.

Acute dissection of the renal artery is rare, and often caused by blunt trauma. These more commonly lead to pseudoaneurysm as compared to true RAA. However, in either case, urgent intervention is generally indicated due to the high risk of rupture and threat to kidney viability.

When planning for open reconstruction of renal arteries, some form of contrast imaging is the key. CT angiography is most commonly used to assess the number and course of the renal arteries, concomitant stenosis, as well as the location of any aneurysm or dissection in relation to these structures. Alternative imaging modalities that may be considered include MRA or contrast angiography. Traditional angiography is often used in cases in which cross-sectional imaging is not adequate or is unclear. Additionally, selection of individual renal vessels can help to assess the contribution of each vessel to renal perfusion.

Patients being considered for open RAA repair share all of the risk factors of many vascular patients. These include but are not limited to, coronary artery disease, diabetes, hyperlipidemia, and hypertension. For this reason, all patients undergoing elective repair should undergo a comprehensive preoperative evaluation, including full cardiac risk stratification.