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INTRODUCTION — Symptomatic abdominal aortic aneurysm (AAA) refers to any of a number of symptoms (eg, abdominal pain, limb ischemia) that can be attributed to the aneurysm. The presence of symptoms increases the risk for AAA rupture, and thus, for most patients with symptomatic AAA, repair should be performed. AAA rupture can also occur in the absence of intervening symptoms. In the United States, rupture of an abdominal aortic aneurysm occurs in about 15,000 patients per year . Without repair, ruptured AAA is nearly always fatal. In spite of significant advances in intensive care unit management and surgical techniques, mortality following repair of ruptured AAA remains high . Surgical outcomes may be improved using endovascular aneurysm repair (EVAR), but aortic endografting under emergency circumstances presents many challenges. Increasing numbers of institutions have initiated protocols for endovascular repair of ruptured AAA with promising results in small series, but not all institutions are equipped to treat ruptured AAAs using minimally-invasive technology.
The management of symptomatic AAA, non-ruptured and ruptured, will be reviewed. The diagnosis and management of asymptomatic AAA and general technical issues of open surgical and endovascular aneurysm repair are discussed elsewhere. (See "Clinical features and diagnosis of abdominal aortic aneurysm" and "Open surgical repair of abdominal aortic aneurysm" and "Endovascular repair of abdominal aortic aneurysm" and "Management of asymptomatic abdominal aortic aneurysm", section on 'Introduction'.)
ANEURYSM TERMINOLOGY — An abdominal aorta with a maximal diameter >3.0 cm is aneurysmal in most adult patients (figure 1). Abdominal aortic aneurysm (AAA) most often affects the segment of aorta between the renal and inferior mesenteric arteries (infrarenal) (figure 2); approximately 5 percent involve the renal (pararenal) or visceral arteries (suprarenal). Most AAAs produce no symptoms. (See "Clinical features and diagnosis of abdominal aortic aneurysm", section on 'Asymptomatic AAA'.)
INITIAL MANAGEMENT — The initial management of the patient with symptomatic (non-ruptured) or ruptured AAA is guided by the hemodynamic status. Hemodynamically unstable patients who are candidates for repair are generally transferred directly from the emergency department to the operating room. Most patients with symptomatic (non-ruptured) AAA are hemodynamically stable but will require admission to definitely determine whether the AAA is the source of the symptoms. Until the AAA can be excluded as a source of symptoms, the patient should be observed in a monitored setting. For patients determined to have a symptomatic AAA, but for whom repair will be delayed to optimize associated medical conditions, we admit the patient to an intensive care unit setting. (See 'Emergent versus delayed repair of symptomatic aneurysm' below.)
Two large bore peripheral intravenous catheters should be placed in all patients (symptomatic, non-ruptured, or ruptured AAA) for medication and fluid administration. In hemodynamically unstable patients with ruptured AAA, indirect evidence from the trauma population and one observational study in patients with AAA suggest that allowing a relatively low systolic blood pressure of 80 to 100 mmHg (permissive hypotension) may prevent further tearing of the aorta and limit blood loss [4-6]. (See "Treatment of severe hypovolemia or hypovolemic shock in adults".)
Pain control is an important part of management. It is important to keep the patient comfortable, but consciousness should be maintained. In patients who remain severely hypertensive despite adequate pain control, short-acting intravenous beta-blockers (eg, esmolol) can be use to titrate the blood pressure to normal values. (See "Pain control in the critically ill adult patient".)
Laboratory studies including complete blood count, electrolytes, blood urea nitrogen, creatinine, liver function tests, prothrombin time, partial thromboplastin time, and a type and cross-match should be obtained. If AAA repair will be undertaken at the hospital to which the patient presented, packed red blood cells should be placed on hold for possible transfusion in the operating room. In patients with ruptured AAA, the patient should have at least 10 units of packed red blood cells available for transfusion, and the blood bank should be alerted to the potential need for massive transfusion. Similar to trauma patients with severe ongoing hemorrhage, patients with ruptured AAA requiring massive transfusion may require transfusion of unmatched blood, and may benefit from packed red blood cell: fresh frozen plasma ratios (PRBC:FFP) ≤2:1 rather than higher ratios. (See "Initial evaluation and management of shock in adult trauma" and "Massive blood transfusion", section on 'Trauma patients'.)
APPROACH TO AAA ASSOCIATED WITH SYMPTOMS — Symptoms associated with AAA may or may not be due to AAA rupture. A presumptive diagnosis of ruptured AAA, which is a surgical emergency, can be made in patients known to have AAA or those with a newly diagnosed AAA who have hypotension and abdominal, flank, or back pain. Although most patients with symptomatic (non-ruptured) AAA will require AAA repair, the timing of and approach to repair differs depending upon the presenting symptoms which may be due to instability of the aneurysm (impending rupture, thromboembolism), rapid expansion of the aneurysm causing abdominal discomfort, or related to inflammatory or infected AAA causing systemic manifestations. The clinical and diagnostic features that distinguish these are discussed in detail elsewhere. (See "Clinical features and diagnosis of abdominal aortic aneurysm", section on 'Clinical features' and "Clinical features and diagnosis of abdominal aortic aneurysm", section on 'Diagnosis'.)
Ruptured AAA — Although there are rare reports of patient survival following a contained rupture of abdominal aortic aneurysm (AAA), in general, without repair, ruptured AAA is uniformly fatal, with death occurring usually within hours and certainly within a week of rupture . Thus, when ruptured AAA is identified, repair should be undertaken emergently to give the patient the best chance for survival [3,8]. (See 'Initial management' above.)
Although AAA repair should be offered to most patients with ruptured AAA, some patients may be at such high risk due to underlying comorbidities that comfort care is appropriate (See 'Decision for comfort care' below.)
Hemodynamically unstable patients with known AAA who present with classic symptoms/signs of rupture (hypotension, flank/back pain, pulsatile mass) should be taken emergently to the operating room for immediate control of hemorrhage and repair of the aneurysm. Efforts to obtain proximal aortic control in the operating room should not be delayed waiting for type-specific blood components. For patients not previously known to have AAA, time may permit a focused ultrasound exam to confirm that an aneurysm is present prior to abdominal exploration, but this is not absolutely required (algorithm 1).
For hemodynamically stable patients suspected of having a ruptured AAA, computed tomography (CT) of the abdomen confirms the rupture but is also important for evaluating whether an endovascular repair is feasible . (See "Clinical features and diagnosis of abdominal aortic aneurysm", section on 'Imaging symptomatic patients' and 'Aneurysm repair' below.)
Impending rupture — Some patients without overt rupture on imaging studies have clinical symptoms or other features on CT scan that may indicate that the aneurysm is rapidly changing in configuration (rapid expansion), or at risk for “impending” rupture. Good risk surgical candidates should generally be repaired in an urgent manner. Clinical features are discussed in detail elsewhere. (See "Clinical features and diagnosis of abdominal aortic aneurysm", section on 'Clinical features' and "Clinical features and diagnosis of abdominal aortic aneurysm", section on 'Ruptured versus nonruptured AAA'.)
Symptomatic (non-ruptured) AAA — Abdominal pain or other symptoms occurring in a patient known to have or newly diagnosed with AAA can present a clinical dilemma. In surgical series, between 5 and 22 percent of AAA are symptomatic [8,10-14]. Symptoms that may be related to AAA include abdominal pain or back pain, signs of acute thromboembolism, and fever. In the absence of rupture, pain or other symptoms attributable to AAA may indicate rapid expansion causing compression of adjacent structures, or an inflammatory or infected AAA [8,14-17]. In the absence of overt or impending rupture, the symptomatic patient should be assessed to determine whether their symptoms are related to the aneurysm, and although not well-studied, when no other cause is apparent, we agree with major society guidelines that suggest urgent repair, provided the patient does not have comorbidities that preclude repair  . (See "Clinical features and diagnosis of abdominal aortic aneurysm", section on 'Are symptoms related to AAA?' and "Clinical features and diagnosis of abdominal aortic aneurysm", section on 'Ruptured versus nonruptured AAA'.)
Abdominal/back/flank pain — Patients presenting with abdominal/back/flank pain in association with AAA should be admitted for further evaluation and monitoring. If an alternative diagnosis cannot be definitively established, symptoms should be presumed to be due to the AAA and a vascular surgical consultation should be obtained. The nature of the presenting symptoms should help determine whether the AAA is the source of the symptoms or simply an incidental finding during work-up of another disease process.
Patients identified with another obvious source (eg, urinary calculi) for their symptoms, should undergo treatment of the other acute disease process and the AAA should be managed electively as an asymptomatic AAA. An inpatient vascular surgical consultation should nevertheless be obtained to confirm that the symptoms are not related to the AAA and to evaluate the need for and timing of AAA repair depending upon the resolution of the acute process. The determination of whether to proceed with elective repair depends upon the rupture risk, which is primarily determined by aortic diameter. The presence of very large AAA (>6.0 cm) may warrant admission even if the aneurysm is not felt to be the source of symptoms. (See "Management of asymptomatic abdominal aortic aneurysm", section on 'Aneurysm diameter and rupture risk' and "Management of asymptomatic abdominal aortic aneurysm", section on 'Very large aneurysm'.)
Thromboembolism — Patients with symptoms and signs of acute thromboembolism should be managed according to the severity of symptoms (acute, subacute, or chronic limb ischemia). If thromboembolism is associated with abdominal pain, for which there is no other conceivable source, the embolus may have originated from a tear in the aortic wall and may be a sign of overt or impending aortic rupture. In the event of AAA rupture, thrombectomy can be performed concurrently with AAA repair.
In the presence of AAA, a full evaluation should be performed to determine the source of the thromboemboli, and should include an electrocardiogram, echocardiogram, contrast-enhanced CT of the aorta from the aortic valve to the iliac bifurcation, and peripheral duplex ultrasound since distal embolization can also be related to concurrent large vessel aneurysm (eg, popliteal artery aneurysm). If the clinical evaluation does not identify an alternative source for thromboembolism, the AAA should be presumed to be the source.
In the absence of AAA rupture, acute ischemic symptoms due to lower extremity thromboembolism from the AAA should be managed with anticoagulation, and thrombectomy (or lysis) as needed. If a lower extremity revascularization procedure is needed, consideration should be given to concurrent AAA repair. Under some circumstances AAA repair can be delayed; however, the risk of recurrent thromboembolism remains until the AAA is repaired. (See "Acute arterial occlusion of the lower extremities (acute limb ischemia)".)
Aortic infection — Patients with fever and other systemic manifestations that suggest infected aortic aneurysm should be treated with urgent surgical debridement and vascular reconstruction. The clinical manifestations and treatment of infected aneurysm are discussed elsewhere. (See "Overview of infected (mycotic) arterial aneurysm".)
Inflammatory aneurysm — A triad of chronic abdominal pain, weight loss, and elevated erythrocyte sedimentation rate in a patient with an AAA is highly suggestive of an inflammatory aneurysm. Patients with inflammatory aneurysms are often more symptomatic than patients with the more typical AAAs, but the incidence of actual rupture may be lower . In patients who present with symptoms, repair should be undertaken regardless of aneurysm diameter. (See "Clinical features and diagnosis of abdominal aortic aneurysm", section on 'Infected versus inflammatory AAA'.)
ANEURYSM REPAIR — Urgent or emergent AAA repair is generally indicated for patients with ruptured AAA and symptomatic (non-ruptured) AAA, provided the risk for repair is not prohibitive [3,8]. The decision of whether or not to offer repair to high-risk patients is discussed below. (See 'Decision for comfort care' below.)
Two methods of aneurysm repair are currently available: open surgery and endovascular aneurysm repair (EVAR).
Endovascular aneurysm repair reduces perioperative (30-day) morbidity and mortality following elective AAA repair [19-24], and there is accumulating evidence that morbidity and mortality following repair of symptomatic  or ruptured AAA may also be reduced [2,7,26-31]. A systematic review identified 23 observational studies with 7040 urgent or emergent open (n = 6300) or endovascular (n = 740) AAA repairs in patients with symptomatic (non-ruptured) or ruptured AAA . Emergency EVAR was associated with a significantly reduced perioperative (30-day) mortality risk relative to open repair (pooled odds ratio [OR] 0.62, 95% CI 0.52-0.75).
To perform emergent endovascular AAA repair, the patient’s aneurysm must meet anatomic criteria for EVAR and the institution must have a defined program for emergency endovascular surgery. Abdominal CT, which is obtained in hemodynamically stable patients, will determine whether the patient with symptomatic (non-ruptured) or ruptured AAA is anatomically suited to endovascular aneurysm repair (EVAR). Although up to 70 percent of patients may be candidates for EVAR, ruptured AAA is more often repaired with open surgical techniques, due to the limited number of centers available to perform emergency EVAR. Transfer to a vascular center is appropriate for hemodynamically stable patients who are anatomically suited to EVAR, particularly if the risk for open repair is high. (See 'Decision for patient transfer' below and 'Risk assessment' below.)
The anatomic requirements for endovascular repair for non-ruptured and ruptured AAA are discussed elsewhere. (See "Endovascular repair of abdominal aortic aneurysm", section on 'Anatomic suitability' and "Surgical and endovascular repair of ruptured abdominal aortic aneurysm", section on 'Criteria for endovascular repair'.)
Risk assessment — The general assessment of perioperative risk for urgent/emergent repair of abdominal aortic aneurysm is similar to that of elective AAA repair; however, the urgency of the clinical situation often precludes a comprehensive evaluation. (See "Management of asymptomatic abdominal aortic aneurysm", section on 'Medical risk assessment'.)
There have been many attempts to quantify the mortality risk associated with ruptured AAA. Unfortunately, no one system or variable has proven to be reliable in predicting mortality with certainty . Factors that are associated with increased mortality following open repair of ruptured AAA include hypotension with a systolic blood pressure <80 mmHg, advanced age (>80 years), cardiac arrest, loss of consciousness, creatinine >1.3 on admission, ischemic heart disease, female sex, and hemoglobin <9.0 on admission [2,33-43]. There are no equivalent studies assessing preoperative risk factors and endovascular aneurysm repair of ruptured AAA. One risk prediction model based upon a population of United States Medicare beneficiaries (ie, >65 years of age), found that mortality following elective AAA repair is predicted by comorbidities, gender, and age with no differential predictors between open or endovascular repair .
For patients with several prognostic factors for poor outcome, the incidence of serious morbidity, such as dialysis dependence, colonic ischemia, and myocardial infarction, is high and the need for surgery related to a complication is also high. The presence of >3 prognostic factors increases the likelihood that the patient will require extended care. For the patient who is older than 80, with renal dysfunction, loss of consciousness, and hemoglobin <9, the chance of survival following open repair of ruptured AAA is almost zero . The presence of multiple risk factors for poor outcome in a patient of advanced age, especially those with a “Do Not Resuscitate” advanced directive or a history of AAA repair refusal should lead to consideration for comfort care. (See 'Decision for comfort care' below.)
Emergent versus delayed repair of symptomatic aneurysm — The timing of AAA repair for hemodynamically stable patients with symptomatic (non-ruptured) AAA remains a clinical challenge. Some patients may benefit from optimization of their medical status prior to repair; however, a definitive recommendation that would suit every clinical situation is not possible.
Several retrospective case series comparing open AAA repair under elective versus emergent circumstances for symptomatic (non-ruptured) AAA have found significantly higher overall rates of perioperative morbidity and mortality for emergent compared with urgent repair (overall 18 to 26 percent versus 4 to 5 percent) [8,45,46]. Another series found no deaths from rupture in patients with symptomatic AAA whose operations were delayed and performed semi-electively . The potential impact of endovascular repair in this subset of patients is unknown, but is unlikely to alter the need for preoperative medical optimization that appears to be beneficial for some patients.
MORBIDITY AND MORTALITY — For symptomatic, non-ruptured AAAs, perioperative mortality rates are similar to those of elective repair; however, the rates of postoperative complications and late survival are intermediate compared with elective or ruptured AAA repair . (See "Management of asymptomatic abdominal aortic aneurysm", section on 'AAA repair' and "Endovascular repair of abdominal aortic aneurysm", section on 'Perioperative morbidity and mortality' and "Open surgical repair of abdominal aortic aneurysm", section on 'Morbidity and mortality'.)
The mortality associated with ruptured AAA may be as high as 90 percent when patients who die at home or upon arrival to the hospital are taken into account. In spite of obvious improvements in pre-hospital care, cardiovascular anesthesia, and critical care, surgical mortality following open repair of ruptured AAA has changed very little, remaining about 30 to 50 percent [48,49]. Although endovascular aneurysm repair may improve survival following AAA rupture, this has not been definitively established. The complications of aneurysm repair and mortality associated with ruptured AAA are discussed in detail elsewhere. (See "Surgical and endovascular repair of ruptured abdominal aortic aneurysm", section on 'Complications' and "Surgical and endovascular repair of ruptured abdominal aortic aneurysm", section on 'Mortality'.)
DECISION FOR PATIENT TRANSFER — Patients with AAA who require emergent or urgent aortic surgery for ruptured or symptomatic (non-ruptured) AAA should be treated at a facility where surgical expertise and/or the perioperative resources necessary for major aortic surgery are available (eg, operating room personnel, an appropriately-trained surgeon, perioperative intensive care) . For patients who present to a facility where these are not available, transfer to a vascular center is appropriate.
Improved outcomes for open surgical repair of ruptured AAA are correlated with surgeon experience with a higher annual caseload of open aneurysm repair per year (non-ruptured and ruptured) correlating with improved outcomes . The shift toward endovascular therapies has reduced the exposure of the general surgeon-in-training to open surgical repair of AAA. As a result, the number of general surgeons in the community experienced with open repair of ruptured AAA is declining. If an appropriate level of surgical care is not available at the institution to which the patients initially presented, the patient should be transferred . If transfer is chosen, the patient and their family should be informed of the potential risk of deterioration during transfer, and the transfer should be accomplished as quickly as possible.
Patients who have a high-risk for open AAA repair may be candidates for endovascular repair. However, for endovascular repair to be undertaken, in addition to having appropriate hospital personnel in place, the institution must have systems in place to support the endeavor. Resources that are needed include:
For most small hospitals and low-volume facilities, these requirements cannot be met. If an institution is not able to perform emergency EVAR, an alternative approach is to provide open repair for hemodynamically unstable patients and transfer for hemodynamically stable patients to an appropriate vascular center.
DECISION FOR COMFORT CARE — Some patients may refuse repair of a ruptured AAA, or are such poor candidates for repair that they are not likely to survive or have a meaningful quality of life even if they recover from the procedure. Although it remains disputed whether endovascular repair decreases mortality in patients with ruptured AAA, patients who have factors associated with a poor prognosis for open AAA repair may have lower rates of morbidity and mortality following EVAR for ruptured AAA, when repair is chosen. (See 'Risk assessment' above.)
A decision must be made according to the wishes of the patient (if known) and family whether to proceed with repair or provide comfort measures. Patients who will not undergo repair are kept pain-free and allowed to expire. In one study of 21 patients, the average time to death following ruptured AAA without repair was seven hours . (See "Pain assessment and management in the last weeks of life".)
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