Open Abdominal Aortic Aneurysm Repair and Concurrent Nonvascular Disease

Synchronous Disease

A variety of nonvascular disease states can coexist with an abdominal aortic aneurysm, and these can be symptomatic or asymptomatic. It is rare that both need to be addressed at the same time. The disease state that is the most life threatening to the patient is always dealt with first. This depends on the size of the aortic aneurysm and the severity of the concurrent disease state. A ruptured abdominal aortic aneurysm for the most part takes priority, but there may be an instance where a patient comes to the hospital with a ruptured AAA with a concurrent nonvascular disease state that is also life threatening, and in this case both are repaired at the same operation.

Treatment of a ruptured AAA and a contaminated abdominal cavity from appendicitis, diverticular abscess, perforated gastric or duodenal ulcer, or suppurative cholecystitis can require ligation of the infrarenal aorta and lower extremity revascularization with an extra-anatomic bypass (axillobifemoral bypass or bilateral axillounifemoral bypass) or in-line aortic reconstruction. In-line reconstruction can be an allograft or autogenous femoral vein. Sometimes a synthetic graft is necessary, and in this case polytetrafluoroethylene (PTFE) is preferred over Dacron because it has a higher resistance to infection.

A patient might present with a pulsatile abdominal mass and hypotension, and an intact AAA may be discovered in the operating room, with the emergency a result of a nonvascular cause. In this scenario, the aneurysm should be left alone and the real life-threatening issue is addressed. This is less likely to happen in current times because of the quality of computed tomography (CT) imaging, which most patients are evaluated with as soon as they arrive to the emergency department, but the inflammatory changes seen on CT make some nonvascular disease states difficult to distinguish from a ruptured AAA.

Aortic aneurysm rupture has been reported after unrelated abdominal surgery, and this is thought to be related to increased collagenase activity. Although this has not been proved, it is an argument for performing simultaneous procedures. Georgopoulous and colleagues demonstrated in a relatively large series of patients with a variety of nonvascular disease states that a one-stage approach is safe and effective.

However, a variety of complications can develop as a result of performing simultaneous procedures. Heparin anticoagulation and difficult hemostasis is a specific problem with concomitant procedures. Following simultaneous procedures, the most feared but relatively rare complication is graft infection, observed with a prevalence of 1.6% for aortoiliac grafts and 1.3% to 3.1% for aortofemoral grafts, with an accompanying mortality between 30% and 60%.

Malignancies were found in 4% of AAA cases in a study by Szilagyi covering a period of 22 years. The cancer should be addressed first to prevent metastatic disease from developing and to discern the prognosis, unless the aneurysm is very large and/or symptomatic, in which case the aneurysm should be repaired first. Lauro and coworkers have raised concerns regarding chemotherapy treatment in patients known to have an AAA larger than 6 cm, specifically patients who also receive aggressive hydration and corticosteroids. Such treatment can result in enlargement of major arteries and can increase the risk of rupture. Patients on chemotherapy undergo CT scanning more frequently, and the aneurysm can be followed more closely for any changes.

EVAR has made staging these concurrent problems even more practical, and in everyday vascular surgical practice, staging these procedures is what is done most commonly. However, when dealing with concurrent disease states in patients who are not candidates for an endovascular repair, simultaneous treatment helps avoid a redo laparotomy.

Gallbladder and Hepatobiliary Disease

Cholelithiasis is the most common abdominal pathology found in the AAA patient, with estimates of prevalence that range from 5% to 20%. Asymptomatic gallstones in the setting of a large AAA should be ignored. The likelihood of acute cholecystitis after AAA repair is low, even if cholelithiasis is present. Ouriel’s group found an incidence of cholecystitis in only 1.1% of 703 elective AAA repairs postoperatively, and the underlying cause was acalculous in 75% of cases.

In our practice, postoperative cholecystitis is rare; however, if it develops the patient can be managed with antibiotics, and when the inflammatory period has subsided the patient could have a staged laparoscopic cholecystectomy. The principle is to allow the patient to recover from the aneurysm repair and to allow time for the aortic graft to become incorporated to lessen the possibility of contamination during the cholecystectomy. If the patient develops sepsis from suppurative cholecystitis, intravenous antibiotics alone will not be adequate, and the gallbladder should be drained with a percutaneous cholecystostomy tube. The patient can then undergo a staged cholecystectomy at a later time.

There are instances when cholecystectomy is necessary during AAA repair. String demonstrated the safety of concomitant cholecystectomy and aortic repair. A patient could present with a ruptured AAA and a diseased gallbladder, in which case the aneurysm is treated first and covered with retroperitoneal tissue, and then a cholecystectomy is performed. The more common scenario, however, would be performing an elective AAA repair or a repair for a ruptured AAA transperitoneally, and at the end of the case, before closing, the gallbladder is found to be ischemic and needs to be removed. In either case the graft should be retroperitonealized before cholecystectomy, and care should be taken to avoid spilling bile.

Simultaneous procedures were proposed for patients with cholelithiasis because half of these patients develop symptoms that require cholecystectomy during the next 5 years. However, there was concern that graft infection could occur, and this was thought to be related to the fact that positive bile cultures are present in 33% of cases. Because of this and because cholecystectomy has become even less invasive, current therapy is to stage these procedures, if possible.

In terms of liver disease, neoplasms or abscesses found on preoperative CT should be treated independently of an aortic aneurysm. Abscesses should be drained and treated with antibiotics, and once the infection is cleared the aneurysm can be treated electively. If the AAA requires urgent repair, it should be approached retroperitoneally, and the abscess can be drained percutaneously with CT guidance.

Liver tumors should be addressed first to assess prognosis unless the aneurysm is very large or symptomatic. If a liver mass is discovered during elective AAA repair it can be biopsied or resected if it is small, but with the accuracy of CT-guided tissue sampling, concomitant liver surgery should be avoided, especially if there is concern for bleeding in a heparinized patient.

Pancreatic Disease

Pancreatic disease usually involves pancreatitis, the sequelae of pancreatitis, and pancreatic neoplasia. An AAA may be identified incidentally on the CT scan done to evaluate a patient with pancreatitis. In this situation the pancreatitis should be allowed to resolve, and once the patient has recovered, the aneurysm should be treated. If a patient develops a pseudocyst from pancreatitis, this should be treated first and consideration should be given to approaching the aneurysm from a left retroperitoneal approach to avoid scar tissue that would be encountered from a midline laparotomy.

A pancreatic tumor that is possibly malignant should be addressed first, because if this is not resectable or if the patient is found to have a poor prognosis, an open AAA repair should not be offered. If during AAA repair a pancreatic mass is encountered that was not evident on the CT scan, valuable information can be gained by performing a biopsy of this mass after completing the AAA repair and retroperitonealizing the graft.