Approach ConsiderationsMore than 80% of patients with ruptured abdominal aortic aneurysm (AAA) present without a previous diagnosis of AAA, which contributes to an initial misdiagnosis rate of 24-42%. A rational approach to the diagnostic evaluation is predicated on a high degree of suspicion. Show
No specific laboratory studies exist that can be used to make the diagnosis of AAA. Laboratory testing may be used to aid in diagnosis of other pathology or associated medical disorders. Options for radiologic evaluation of AAA include ultrasonography (US), plain radiography, computed tomography (CT), magnetic resonance imaging (MRI), and angiography.  Laboratory StudiesA complete blood count (CBC) with differential is used to assess transfusion requirements and the possibility of infection. A metabolic panel (including kidney and liver function tests) is indicated for ascertaining the integrity of renal and hepatic function and thus help assess operative risk and guide postoperative management. Blood must be typed and crossmatched to prepare for the possibility of transfusion, including clotting factors and platelets. Because synthetic material is used in the intervention, any potential foci of infection should be assessed and eliminated preoperatively with the aid of urinalysis. The preoperative workup should also include assessment of pulmonary function to help evaluate operative risk and determine postoperative care. Patients who can climb a flight of stairs without excessive shortness of breath generally do well. If the patient’s pulmonary status is in question, blood gas measurement and pulmonary function tests are helpful. UltrasonographyUS is the standard imaging tool for AAA (see the image below). When performed by trained personnel, it has a sensitivity of nearly 100% and a specificity approaching 96% for the detection of infrarenal AAA. US can also detect free peritoneal blood. US is noninvasive and may be performed at the bedside. Bedside emergency US should be performed immediately if AAA is suspected. Elderly patients with abdominal pain are prime candidates for bedside US screening. (See Bedside Ultrasonography Evaluation of Abdominal Aortic Aneurysm.) Screening for AAA reduces the mortality from rupture and is cost-effective. [14] The US Preventive Services Task Force has recommended US screening in men aged 65-75 years who have smoked. [4, 6] Abdominal US can provide a preliminary determination of aneurysm presence, size, and extent. In addition, it is a cost-effective modality for monitoring patients whose aneurysms are too small for surgical intervention. It is also useful for follow-up after endovascular surgery to assess the durability of the repair. Limitations of US in this setting are few but include inability to detect leakage, rupture, branch artery involvement, and suprarenal involvement. In addition, the ability to image the aorta is reduced in the presence of bowel gas or obesity. Significant portions of the abdominal aorta (at least one third of its length) are not visualized on bedside emergency US in 8% of nonfasting patients. [15] This rate is higher than reported for fasting patients receiving elective US for evaluation of their aortas. Plain RadiographyPlain radiography is often performed on patients with abdominal complaints before the diagnosis of AAA has been entertained. Using this method to evaluate patients with AAA is difficult because the only marginally specific finding, aortic wall calcification, is seen less than half of the time. Aortic-wall calcification (see the images below) may appear without aneurysm rim calcification, resulting in a high false-negative rate. Plain radiography should not, however, be ordered for the sole purpose of evaluating suspected AAA; because of its low diagnostic yield, its use can waste time, delay care, and place the patient at risk for aortic rupture and death. Chest radiography may be employed to gain a preliminary assessment of the status of the heart and lungs. Concurrent pulmonary or cardiac disease may have to be addressed before the AAA is treated. Computed TomographyCT has a sensitivity of nearly 100% for detecting AAA, and it has certain advantages over US for defining aortic size, rostral-caudal extent, involvement of visceral arteries, and extension into the suprarenal aorta (see the image below). CT permits visualization of the retroperitoneum, is not limited by obesity or bowel gas, detects leakage, and allows concomitant evaluation of the kidneys. Spiral (helical) CT allows three-dimensional (3D) imaging of abdominal contents, facilitating detection of branch vessel and adjacent organ involvement. Preoperative CT is helpful for more clearly defining the anatomy of the aneurysm and other intra-abdominal pathologic conditions. Nonenhanced CT is used to size aneurysms. [16] As important as sizing the aneurysm is determining the anatomic relations that are relevant to surgical repair. These include the location of the renal arteries, the length of the aortic neck, the condition of the iliac arteries, and the presence of anatomic variants such as a retroaortic left renal vein or a horseshoe kidney. Enhanced spiral CT of the abdomen and pelvis with multiplanar reconstruction and CT angiography (CTA) is the modality of choice for preoperative evaluation for open and endovascular repair (see the image below). In 10-20% of AAA cases, CT scans show focal outpouchings or blebs that are thought to contribute to the potential for rupture. The wall of the aneurysm becomes laminated with thrombus as the blebs enlarge. This process can yield the appearance of a relatively normal intraluminal diameter in spite of a large extraluminal size. CT is the best modality for determining whether a patient is a candidate for endovascular aneurysm repair (EVAR). It can assess the aneurysm neck diameter, length, and angulation, as well as thrombus within the neck. The CT scan is also useful for assessing iliac vessel diameter, calcification, and tortuosity, which are important for determining whether the endovascular device can be advanced from the femoral artery. Major disadvantages of CT include potential difficulties with technician availability, higher cost, longer study time, exposure to radiation and contrast material, and the need to send patients with possible rupture out of the emergency department for an extended period. Magnetic Resonance ImagingMRI permits imaging of the aorta comparable to that achievable with CT and US, but without subjecting the patient to a dye load or ionizing radiation (see the image below). It may offer better imaging of branch vessels than either CT or US does, but it is less valuable in assessing suprarenal extension and is not suitable in patients who are unstable. MRI may have a role in very stable patients with a severe dye allergy. Limitations of MRI in the assessment of AAA are the lack of widespread availability, the need for a stable patient, potential incompatibility with monitoring equipment, and high cost. AngiographyBecause of advances in CT imaging with 3D reconstruction capability, angiography (see the images below) currently is less often used in preoperative evaluation of AAA than it once was. Arteriography may miss an AAA if there is a lack of calcification because of the laminated thrombus within the AAA making a more normal-appearing aortic lumen. It is primarily used intraoperatively to facilitate endovascular repair. Limitations on the use of angiography include the invasiveness of the procedure, the cost, the potential lack of operator availability, the considerable time involved, and the risk of complications (eg, bleeding, perforation, and embolization). Routine use of angiography in the evaluation of AAA is not recommended. Digital subtraction angiography (DSA) requires less time, uses less contrast material, and is less invasive than conventional angiography. However, DSA is not widely available and offers no real advantage over conventional CT. Intra-aortic CTA (IA-CTA) has good sensitivity for locating the Adamkiewicz artery (AKA) in patients with thoracoabdominal aortic aneurysms. In one study, the AKA was visualized by IA-CTA in 27 of 30 cases (90%) before surgery for aneurysm or dissection of the thoracoabdominal aorta. [17] Continuity with the aorta was satisfactorily seen in 26 of 31 (84%) cases. Spinal angiography by selective catheterization confirmed the results of IA-CTA in 75% of cases in which the AKA was visualized. In a number of centers, magnetic resonance angiography (MRA) is replacing traditional angiographic assessment of aneurysms. MRA provides excellent anatomic definition and 3D assessment of the problem. Gadolinium-enhanced MRA can provide excellent images, even though regional variations in quality are reported. EchocardiographyBecause of the fluid shift involved during the operative repair of AAA, cardiac function should be assessed by means of echocardiography. Ascertaining the ejection fraction of the patient facilitates planning of the operative intervention and institution of cardiac protective measures as needed. This study is particularly indicated in patients with a history of congestive heart failure or known cardiac enlargement. Other TestsAssessment of pulmonary function is of paramount importance in AAA patients. Because surgical intervention requires an abdominal incision, preoperative assessment of the patient’s pulmonary status allows postoperative care to be appropriately tailored to the patient’s condition. Assessment of cardiac status is mandatory in all patients with vascular disease. If one vascular bed is involved with an atherosclerotic process, others may be involved as well. Electrocardiographic (ECG) findings provide a baseline assessment of cardiac rhythm and old disease processes. A stress test can be performed to uncover unsuspected cardiac ischemia. Significant coronary disease may have to be addressed before the AAA can be repaired. On histologic examination, AAAs contain a chronic inflammatory infiltrate and neovascularity of varying degrees. Inflammatory AAAs may contain germinal centers.
Author Saum A Rahimi, MD, FACS Interim Chief, Assistant Professor of Surgery, Division of Vascular Surgery, Rutgers Robert Wood Johnson Medical School Saum A Rahimi, MD, FACS is a member of the following medical societies: American College of Surgeons, Society for Vascular Surgery, Eastern Vascular Society, Vascular Society of New Jersey Disclosure: Nothing to disclose. Chief Editor Vincent Lopez Rowe, MD Professor of Surgery, Program Director, Integrated Vascular Surgery Residency and Fellowship, Department of Surgery, Division of Vascular Surgery and Endovascular Therapy, Keck School of Medicine of the University of Southern California Vincent Lopez Rowe, MD is a member of the following medical societies: American College of Surgeons, American Surgical Association, Pacific Coast Surgical Association, Society for Clinical Vascular Surgery, Society for Vascular Surgery, Western Vascular Society Disclosure: Nothing to disclose. Acknowledgements Suman Annambhotla, MD Fellow in Vascular Surgery, Northwestern University, The Feinberg School of Medicine Suman Annambhotla, MD is a member of the following medical societies: American College of Surgeons, American Medical Association, Association for Academic Surgery, and Society for Vascular Surgery Disclosure: Nothing to disclose. Edward Bessman, MD, MBA Chairman and Clinical Director, Department of Emergency Medicine, John Hopkins Bayview Medical Center; Assistant Professor, Department of Emergency Medicine, Johns Hopkins University School of Medicine Edward Bessman, MD, MBA is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine Disclosure: Nothing to disclose. David FM Brown, MD Associate Professor, Division of Emergency Medicine, Harvard Medical School; Vice Chair, Department of Emergency Medicine, Massachusetts General Hospital David FM Brown, MD is a member of the following medical societies: American College of Emergency Physicians and Society for Academic Emergency Medicine Disclosure: lippincott Royalty textbook royalty; wiley Royalty textbook royalty Jeffrey Lawrence Kaufman, MD Associate Professor, Department of Surgery, Division of Vascular Surgery, Tufts University School of Medicine Jeffrey Lawrence Kaufman, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Surgeons, American Society for Artificial Internal Organs, Association for Academic Surgery, Association for Surgical Education, Massachusetts Medical Society, Phi Beta Kappa, and Society for Vascular Surgery Disclosure: Nothing to disclose. Robert E O'Connor, MD, MPH Professor and Chair, Department of Emergency Medicine, University of Virginia Health System Robert E O'Connor, MD, MPH is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American College of Physician Executives, American Heart Association, American Medical Association, Medical Society of Delaware, National Association of EMS Physicians, Society for Academic Emergency Medicine, and Wilderness Medical Society Disclosure: Nothing to disclose. William H Pearce, MD Chief, Division of Vascular Surgery, Violet and Charles Baldwin Professor of Vascular Surgery, Department of Surgery, Northwestern University, The Feinberg School of Medicine William H Pearce, MD is a member of the following medical societies: American College of Surgeons, American Heart Association, American Surgical Association, Association for Academic Surgery, Association of VA Surgeons, Central Surgical Association, New York Academy of Sciences, Society for Vascular Surgery, Society of Critical Care Medicine, Society of University Surgeons, andWestern Surgical Association Disclosure: Nothing to disclose. Gary Setnik, MD Chair, Department of Emergency Medicine, Mount Auburn Hospital; Assistant Professor, Division of Emergency Medicine, Harvard Medical School Gary Setnik, MD is a member of the following medical societies: American College of Emergency Physicians, National Association of EMS Physicians, and Society for Academic Emergency Medicine Disclosure: SironaHealth Salary Management position; South Middlesex EMS Consortium Salary Management position; ProceduresConsult.com Royalty Other Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference Disclosure: Medscape Salary Employment What is the postoperative care for abdominal aortic aneurysm AAA )?Avoid strenuous activities that may put stress on your incision, such as bicycle riding, jogging, weight lifting, or aerobic exercise, for 6 weeks or until your doctor says it is okay. For 6 weeks, avoid lifting anything that would make you strain.
What assessment should a nurse perform on a patient after the repair of an abdominal aortic aneurysm?Nursing Management
Check by palpation for a pulsating mass in the abdomen, at or above the umbilicus. Auscultate for a bruit over the abdominal aorta. Determine if there is tenderness on palpation (do not palpate too deep as there is a risk of rupture). Ask if the patient has abdominal or lower back pain.
How do you monitor an abdominal aortic aneurysm?Screening for AAA involves a quick and painless ultrasound scan of your tummy. This is similar to the scan pregnant women have to check on their baby. When you arrive for your appointment, a screening technician will check your details, explain the scan and ask if you have any questions.
Which is the most common complication after an abdominal aortic aneurysm resection?The most common complications associated with resection of aneurysms of the thoracic and abdominal aorta are: hemorrhage, acute renal failure, ischemic colitis, distal emboli, graft thrombosis, infection, pseudoaneurysm formation, aorto-caval and aorto-enteric fistulae, neurologic deficits, ureteral obstruction, sexual ...
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You are monitoring a patient post abdominal aortic aneurysm repair
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