The natural history of abdominal aortic aneurysms is that of continued enlargement with risk of rupture increasing with increasing aneurysm size, rapid growth rate (>1 cm/year), COPD, hypertension, and family history of AAA rupture. Management of abdominal aortic aneurysms relies upon early diagnosis, serial observation, and treatment by way of open or endovascular means. The primary goal of surgical repair is prevention of rupture and aneurysm related mortality.

The majority of abdominal aortic aneurysm (>80%) are infrarenal in nature for which both endovascular and open reconstruction options exist. Pararenal aneurysms are defined by an infrarenal aneurysm neck of less than or equal to 1 cm and the term pararenal is synonymous and interchangeable with the term juxtarenal. Suprarenal aneurysms are defined as those with one or both main renal arteries arising from the aneurysm itself, implying that separate renal artery reconstructions will be required. In instances of complex proximal anatomy, cross-clamp application in a suprarenal or supraceliac position to permit the proximal aortic reconstruction will be necessary during open repair. At present no endovascular options exist for the management of suprarenal aneurysms; however, owing to current commercial availability of a single fenestrated endovascular device, some patients with pararenal aneurysms with short necks (≤4 mm) and appropriate visceral vessel topography and anatomy may qualify for endovascular repair. This chapter will emphasize the cognitive and technical repair of open pararenal and suprarenal aortic aneurysms.

The majority of abdominal aortic aneurysms are asymptomatic, however some may present with signs and symptoms including thrombosis, embolization of mural debris, compression of adjacent organs, aortic dissection, rapid expansion or impending rupture, and frank rupture. The presence of associated symptoms warrants early repair independent of aneurysm size. Mural debris which accumulates along the aneurysmal aortic wall may contribute to progressive aortic thrombosis resulting in symptoms
ranging from claudication to severe ischemia in cases of complete thrombosis. More distal embolization may present with digital ischemia or gangrene referred to as “trash foot” or “blue toe syndrome.” Dissection within an aneurysmal aorta presents with acute onset severe abdominal or back pain, often described as tearing in nature, and is associated with a significant increase in rupture risk thereby necessitating urgent repair. Aneurysms presenting with symptoms of rapid expansion or impending rupture and are associated with abdominal, back, or flank pain and in cases of frank rupture may present with hemodynamic instability. Computed tomographic angiography (CTA) findings of heterogeneous mural thrombus, intraplaque hemorrhage, loss of fat planes around the aortic aneurysm, periaortic inflammation, and retroperitoneal hematoma are findings suggestive of rupture and urgent AAA repair should be undertaken. Hemodynamic instability in patients with known AAA should prompt emergent exploration and repair; in our practice patients undergo rapid resuscitation with permissive hypotension and rapid CTA if no recent imaging is available to facilitate operative planning and patient positioning.

The majority of AAA are asymptomatic; therefore, natural history data aid in balancing aneurysm rupture risk with that of surgical morbidity and mortality. Rupture risk correlates directly with aneurysm size and is very low for aneurysms smaller than 5 cm in diameter. Based on clinical trial data, an aneurysm diameter of 5.5 cm is typically used as a threshold for open repair. Other predictors of rupture include female gender, family history of AAA, smoking status, hypertension, and COPD. Aneurysm repair is most effective if the risk of rupture and aneurysm related death outweighs the operative risk to the patient and the patients’ life expectancy. The natural history of patients under surveillance is such that 70% to 80% of patients eventually undergo aneurysm repair.

Open repair of pararenal and suprarenal aneurysms can be readily performed using both transperitoneal/transabdominal (TP) or retroperitoneal (RP) approaches. The transperitoneal approach can be performed with the patient placed in supine position using a longitudinal midline (xiphoid to pubis) incision, or a transverse incision extending from flank to flank. The retroperitoneal approach is performed with the patient in a right lateral decubitus position using a left flank incision and the approach can vary from a total retroperitoneal to thoracoabdominal exposure. Depending on body habitus, aneurysm anatomy, other anatomic factors, and surgeon preference, either approach can be used for the majority of infrarenal and pararenal AAA, whereas suprarenal aneurysms are better approached by one of the left flank approaches. There exist certain anatomic and clinical circumstances which dictate preferential use of a particular approach in individual patients.