cardiovascular disorders
Abdominal Aortic Aneurysms (AAA)
Diagnosis of Abdominal Aortic Aneurysms
Often incidental Confirmation by ultrasonography or abdominal CT Sometimes CT angiography or magnetic resonance angiography Most abdominal aortic aneurysms are diagnosed incidentally when they are detected during physical examination or when abdominal ultrasonography, CT, or MRI is done for other reasons. An AAA should be considered in older patients who present with acute abdominal pain or back pain whether a palpable pulsatile mass is present or not. This patient has an abdominal aortic aneurysm measuring 3.4 cm (between the white crosses) as well as atherosclerotic plaque or mural thrombus (red arrow). © 2017 Elliot K. Fishman, MD. The white arrow shows an abdominal aortic aneurysm measuring 5 cm with heterogenous flow and mural plaque. © 2017 Elliot K. Fishman, MD. The white arrow shows a suprarenal abdominal aortic pseudoaneurysm. There is also extensive plaque in the infrarenal aorta and iliac arteries. © 2017 Elliot K. Fishman, MD. When symptoms or physical examination findings suggest AAA, abdominal ultrasonography or abdominal CT is usually the test of choice. Symptomatic patients should have immediate testing to make the diagnosis before catastrophic rupture. For hemodynamically unstable patients with presumed rupture, ultrasonography provides bedside results more rapidly, but intestinal gas and distention may limit its accuracy. Laboratory tests, including complete blood count (CBC), electrolytes, bloodureanitrogen (BUN), creatinine, prothrombin time (PT), partial thromboplastin time (PTT), and blood type and cross-match, are done in preparation for possible surgery. If rupture is not suspected, CT angiography (CTA) or magnetic resonance angiography (MRA) can more precisely characterize aneurysm size and anatomy. If thrombi line the aneurysm wall, conventional angiography may underestimate true size; CT may provide a more accurate estimate. Aortography is sometimes necessary if renal artery or aortoiliac disease is suspected or if correction with endovascular stent grafts (endografts) is being considered. Plain abdominal x-rays are neither sensitive nor specific; however, if obtained for other purposes, x-rays may show aortic calcification outlining the aneurysm wall. If a mycotic aneurysm is suspected, bacterial and fungal blood cultures should be done. Screening men age > 65 years with abdominal ultrasonography decreases mortality, but the absolute reduction is small for men who are otherwise at low risk. Screening also can also provoke anxiety, particularly for aneurysms managed expectantly. Some authorities recommend shared decision-making. 