# Ruptured Abdominal Aortic Aneurysm: Emergency Management ## Overview Ruptured abdominal aortic aneurysm (rAAA) represents a surgical emergency with a very high overall mortality rate of 65-85%, which includes deaths occurring before hospital arrival. For patients who reach the operating room, in-hospital mortality remains substantial at 30-50%. In the United States alone, rAAA accounts for approximately 15,000 deaths annually. Rapid diagnosis and prompt decision-making are essential to improve outcomes. Endovascular repair (EVAR) is increasingly utilized in the management of rAAA and may reduce perioperative mortality compared to traditional open repair. ## Presentation ### Classic Triad The classic presentation of rAAA includes a sudden onset of severe abdominal or back pain, hypotension or hemodynamic instability, and a pulsatile abdominal mass. However, all three features are present in only about half of cases, making diagnosis challenging. Misdiagnosis is common, with conditions such as renal colic, diverticulitis, and musculoskeletal back pain frequently mistaken for rAAA. ### Variants Several variants of rAAA exist. The most common is a contained rupture, where the retroperitoneum tamponades the bleeding, allowing the patient to be transiently stable. Free intraperitoneal rupture leads to rapid exsanguination and is often fatal before hospital arrival. An aortocaval fistula occurs when the aneurysm ruptures into the inferior vena cava, causing high-output heart failure, an abdominal bruit, and lower extremity edema. A primary aortoenteric fistula, a rare complication, involves rupture into the duodenum and presents with gastrointestinal hemorrhage; this is more common in patients with prior grafts than in those with intact aneurysms. ### Differential Diagnosis The differential diagnosis for suspected rAAA includes renal colic, acute pancreatitis, mesenteric ischemia, myocardial infarction, perforated viscus, and musculoskeletal back pain. ## Diagnosis Clinical suspicion is paramount in diagnosing rAAA, and imaging should not delay surgical intervention in unstable patients. Computed tomography angiography (CTA) is the confirmatory test in hemodynamically stable patients, revealing findings such as retroperitoneal hematoma, contrast extravasation, and aortic discontinuity. CTA also provides crucial anatomic information for planning endovascular repair if applicable. Bedside ultrasound can rapidly confirm the presence of an abdominal aortic aneurysm in the emergency department but cannot reliably diagnose rupture. Magnetic resonance imaging has no role in the emergency setting. For unstable patients with a known AAA and acute symptoms, immediate transfer to the operating room without imaging is indicated. CT angiography axial and coronal images of a ruptured abdominal aortic aneurysm showing a large retroperitoneal hematoma with active contrast extravasation, the draped aorta sign, and the intact contralateral retroperitoneum containing the rupture ## Initial Management ### Permissive Hypotension The initial management of rAAA involves permissive hypotension, targeting a systolic blood pressure of 70-90 mmHg or a mean arterial pressure of 50-60 mmHg until aortic control is achieved. Aggressive fluid resuscitation can raise blood pressure excessively, dislodge the forming clot, and worsen hemorrhage. The clinical endpoint is maintaining consciousness rather than normal blood pressure. Large-volume crystalloid resuscitation should be avoided, and blood products should be limited until the patient reaches the operating room, except as needed to maintain permissive hypotension targets. This approach, adapted from trauma surgery, is critical for improving survival in rAAA. ### Resuscitation Principles Resuscitation requires establishing two large-bore intravenous lines or central venous access and ensuring type and crossmatch for blood availability, with activation of a massive transfusion protocol if necessary. Permissive hypotension should be maintained as described. Minimizing the time to aortic control is essential. Hypothermia must be avoided by using warmed fluids and external warming devices such as bear huggers. Coagulopathy should be corrected with balanced transfusion strategies, typically a 1:1:1 ratio of red blood cells, fresh frozen plasma, and platelets if massive transfusion is required. ### Decision to Operate All hemodynamically unstable patients with suspected rAAA should proceed immediately to the operating room. In stable patients, a brief CTA can be performed for diagnosis and to plan EVAR if the institutional protocol allows. Cardiac workup, echocardiography, or other testing should not delay surgery. Goals-of-care discussions are appropriate for very elderly patients, those with multiple comorbidities, or when patient wishes are known. ## Surgical Management ### Open Repair of rAAA #### Approach Open repair is performed via a midline laparotomy to provide rapid access. Immediate aortic control is the priority to prevent ongoing hemorrhage. #### Aortic Control Options There are several options for proximal aortic control. Infrarenal cross-clamping is ideal if the anatomy permits, but this is rarely achievable in the ruptured setting without initial proximal control. The most reliable method is supraceliac clamping, which involves identifying the aorta at the diaphragmatic hiatus, manually compressing it against the spine, and then applying the clamp. After repair, the clamp should be moved infrarenally as soon as possible. Manual aortic compression at the diaphragm can be used temporarily while dissecting for clamp placement. #### Operative Steps The procedure begins with supraceliac control, followed by exposure of the infrarenal aorta through the retroperitoneal hematoma. The aneurysm sac is opened, and thrombus and blood are evacuated. Back-bleeding lumbar arteries are controlled. A prosthetic graft, either tube or bifurcated, is then placed in an inlay fashion. Hemostasis and speed are prioritized throughout the operation. The aneurysm sac is closed over the graft, and bowel viability is assessed before abdominal closure. ### Endovascular Repair of rAAA (rEVAR) #### Requirements Endovascular repair requires anatomic suitability, including an adequate proximal neck and iliac artery anatomy, which is assessed on CTA. Appropriate-size endografts must be available "on the shelf," and an experienced team with access to a hybrid operating room is necessary. An aortic occlusion balloon is placed via contralateral femoral access to achieve proximal control during the procedure. #### Technique Bilateral femoral access is obtained either by cutdown or percutaneous methods. The aortic occlusion balloon, such as a CODA balloon, is inflated in the supraceliac or suprarenal aorta to control hemorrhage. The endograft is then deployed following standard EVAR techniques. After deployment, the occlusion balloon is deflated and removed, and completion angiography is performed to confirm successful repair. #### rEVAR Outcomes The IMPROVE trial demonstrated that rEVAR did not confer an overall mortality benefit over open repair at 30 days but showed lower mortality in women, shorter ICU stays, and a reduced rate of abdominal compartment syndrome. At three years, rEVAR was associated with lower costs and improved quality of life. The AJAX trial reported similar findings, with no overall mortality benefit. Real-world data suggest that rEVAR benefits patients in experienced centers with suitable anatomy. Illustration comparing open surgical repair and endovascular repair strategies for ruptured AAA, showing supraceliac clamping with open graft placement on one side and aortic occlusion balloon with endograft deployment on the other, highlighting key steps in each approach ## Abdominal Compartment Syndrome (ACS) ### Pathophysiology Abdominal compartment syndrome arises from massive fluid resuscitation leading to bowel edema and increased intra-abdominal pressure (IAP). When IAP exceeds 20 mmHg and is accompanied by organ dysfunction, ACS is diagnosed. It is more common after open repair, especially in the setting of prolonged hemorrhage and massive resuscitation. ### Effects ACS affects multiple organ systems. Respiratory compromise occurs due to elevation of the diaphragm, decreased lung compliance, and resultant hypoxia. Cardiovascular effects include decreased venous return and cardiac output. Renal perfusion is reduced, causing oliguria or anuria. Neurologically, increased intracranial pressure may develop secondary to impaired venous drainage. ### Monitoring Bladder pressure measurement is the standard method for monitoring intra-abdominal pressure. Normal IAP ranges from 5 to 7 mmHg, with values above 20 mmHg accompanied by organ dysfunction indicating ACS. ### Management Prevention of ACS involves damage control surgery, avoiding over-resuscitation, and employing temporary abdominal closure techniques. Definitive treatment is decompressive laparotomy, leaving the abdomen open with negative-pressure wound therapy (VAC) and planning delayed fascial closure once edema resolves. In patients who are coagulopathic, hypothermic, or acidotic, a damage control approach with packing and temporary closure is recommended. ## Damage Control Surgery Damage control surgery is applied when the patient exhibits the "lethal triad" of hypothermia, acidosis, and coagulopathy. The operative goals are to achieve aortic control, place the graft, and secure hemostasis. The procedure is abbreviated by deferring non-essential steps, followed by temporary abdominal closure. The patient is then transferred to the ICU for resuscitation aimed at correcting coagulopathy, rewarming, and optimizing hemodynamics. Planned re-exploration occurs within 24 to 48 hours. ## Post-Operative Complications In-hospital mortality after rAAA repair remains high at 30-50%. Myocardial infarction is the leading cause of death. Acute kidney injury occurs in 20-40% of patients, exacerbated by hypotension, suprarenal clamping, and contrast exposure. Ischemic colitis affects 5-15% of patients, with a higher incidence than in elective repair due to hypotension. Clinical signs include bloody stools, leukocytosis, and acidosis; sigmoid colonoscopy is indicated if suspected. Full-thickness necrosis necessitates emergent colectomy, which carries a mortality exceeding 80%. Multiorgan failure is a common cause of delayed death. Lower extremity ischemia may result from embolization or compartment syndrome. Abdominal compartment syndrome and respiratory failure requiring prolonged ventilation are also frequent complications. ## Prognostic Factors Prognosis is poor in patients who experience pre-hospital cardiac arrest, with nearly uniform fatality. Loss of consciousness or hemodynamic collapse portends a poor outcome. Age over 80 years significantly increases mortality risk. Preoperative creatinine levels above 2.0 mg/dL and hemoglobin below 9 g/dL are associated with worse outcomes. Free intraperitoneal rupture carries a worse prognosis compared to contained retroperitoneal rupture. ## Clinical Pearls Survival in rAAA hinges on getting the patient to the operating room alive, and permissive hypotension is a lifesaving strategy. Aggressive resuscitation to normalize blood pressure before aortic control should be avoided, as it can be fatal. Supraceliac clamping remains the most reliable method for rapid proximal control during open repair. It is essential to inspect the colon before abdominal closure because ischemic colitis is common and can be deadly if missed. An aortic occlusion balloon should be available in every rAAA case, whether open or endovascular. rEVAR is a reasonable option when anatomy is suitable and the team is experienced, but open repair capability must always be available as a backup. Damage control principles apply when the patient is coagulopathic, hypothermic, and acidotic, warranting an abbreviated procedure. Finally, goals-of-care discussions are appropriate in very elderly or moribund patients, as not every rAAA patient should undergo surgery. Damage control surgery algorithm for ruptured AAA showing decision points from initial resuscitation through operative strategy (abbreviated open repair or rEVAR), temporary abdominal closure, ICU resuscitation phase, and planned re-exploration ## References - IMPROVE Trial Investigators. Endovascular or open repair strategy for ruptured abdominal aortic aneurysm: 30 day outcomes from IMPROVE randomised trial. BMJ. 2014;348:f7661. - IMPROVE Trial Investigators. Comparative clinical effectiveness and cost effectiveness of endovascular strategy vs open repair for ruptured abdominal aortic aneurysm: three-year results. BMJ. 2017;359:j4859. - Mayer D, et al. Aortic occlusion balloon for ruptured AAA. J Vasc Surg. 2009;50(3):503-509. - Chaikof EL, et al. SVS practice guidelines on AAA. J Vasc Surg. 2018;67(1):2-77. - Dick F, et al. Outcome and quality of life after open and endovascular repair of ruptured AAA. Eur J Vasc Endovasc Surg. 2010;40(3):277-284.