Occlusion of branches of the abdominal aorta may be
Acute: Resulting from embolism, atherothrombosis, or dissection
Chronic: Resulting from atherosclerosis Atherosclerosis Atherosclerosis is characterized by patchy intimal plaques (atheromas) that encroach on the lumen of medium-sized and large arteries; the plaques contain lipids, inflammatory cells, smooth muscle... read more , fibromuscular dysplasia Fibromuscular Dysplasia Fibromuscular dysplasia includes a heterogenous group of nonatherosclerotic, noninflammatory arterial changes, causing some degree of vascular stenosis, occlusion, or aneurysm. Fibromuscular... read more , or external compression by mass lesions
Common sites of occlusion include
Superior mesenteric arteries
Chronic occlusion of the celiac axis is more common among women for unclear reasons.
Symptoms and Signs of Abdominal Aortic Branch Occlusion
Clinical manifestations (eg, pain, organ failure, necrosis) result from ischemia or infarction and vary depending on the artery involved and acuity.
Acute mesenteric occlusion Acute Mesenteric Ischemia Acute mesenteric ischemia is interruption of intestinal blood flow by embolism, thrombosis, or a low-flow state. It leads to mediator release, inflammation, and ultimately infarction. Abdominal... read more causes intestinal ischemia and infarction, resulting in severe, diffuse abdominal pain typically out of proportion to the minimal physical findings. Acute occlusion of the celiac axis may cause liver or spleen infarction.
Chronic mesenteric vascular insufficiency rarely causes symptoms unless both the superior mesenteric artery and celiac axis are substantially narrowed or occluded because collateral circulation between the major splanchnic trunks is extensive. Symptoms of chronic mesenteric vascular insufficiency typically occur postprandially (as intestinal angina) because digestion requires increased mesenteric blood flow; pain begins about 30 minutes to 1 hour after eating and is steady, severe, and usually periumbilical and may be relieved by sublingual nitroglycerin. Patients become fearful of eating; weight loss, often extreme, is common. Rarely, malabsorption develops and contributes to weight loss. Patients may have an abdominal bruit, nausea, vomiting, diarrhea or constipation, and dark stools.
Acute renal artery embolism Acute renal artery occlusion Renal artery stenosis is a decrease in blood flow through one or both of the main renal arteries or their branches. Renal artery occlusion is a complete blockage of blood flow through one or... read more causes sudden flank pain, followed by hematuria. Chronic occlusion may be asymptomatic or result in new or hard-to-control hypertension Hypertension Hypertension is sustained elevation of resting systolic blood pressure (≥ 130 mm Hg), diastolic blood pressure (≥ 80 mm Hg), or both. Hypertension with no known cause (primary; formerly, essential... read more and other sequelae of renal insufficiency or failure.
Acute occlusion of the aortic bifurcation or distal branches can cause sudden onset of pain at rest, pallor, paralysis, absence of peripheral pulses, and coldness in the legs (see Acute Peripheral Arterial Occlusion Acute Peripheral Arterial Occlusion Peripheral arteries may be acutely occluded by a thrombus, an embolus, aortic dissection, or acute compartment syndrome. Acute peripheral arterial occlusion may result from: Rupture and thrombosis... read more ). Chronic occlusion can cause intermittent claudication in the legs and buttocks and erectile dysfunction (Leriche syndrome). Femoral pulses are absent. A limb may be jeopardized.
Diagnosis of Abdominal Aortic Branch Occlusion
Diagnosis is based primarily on history and physical examination and is confirmed by duplex ultrasonography, CT angiography, magnetic resonance angiography, or traditional angiography.
Treatment of Abdominal Aortic Branch Occlusion
Embolectomy or percutaneous transluminal angioplasty for acute occlusion
Surgery or angioplasty for chronic, severe occlusion
Acute occlusion is a surgical emergency requiring embolectomy or percutaneous transluminal angioplasty (PTA) with or without stent placement. A laparotomy with bypass graft and bowel resection may be necessary if embolectomy or PTA is unsuccessful.
Chronic occlusion, if symptomatic, may require surgery or angioplasty. Risk factor modification and antiplatelet drugs may help.
Acute mesenteric occlusion (eg, in the superior mesenteric artery), which causes significant morbidity and mortality, requires prompt revascularization. Prognosis is poor if the intestine is not revascularized within 4 to 6 hours.
For chronic occlusion of the superior mesenteric artery and celiac axis, dietary modifications may temporarily relieve symptoms. If symptoms are severe, surgical bypass from the aorta to the splanchnic arteries distal to the occlusion usually results in revascularization. Long-term patency of the grafts exceeds 90%. In appropriately selected patients (particularly among older patients who may be poor candidates for surgery), revascularization by PTA with or without stent placement may be successful. Symptoms may resolve rapidly, and weight may be regained.
Acute renal artery occlusion requires embolectomy; sometimes PTA can be done. Initial treatment of chronic occlusion involves antihypertensives Drugs for Hypertension A number of drug classes are effective for initial and subsequent management of hypertension: Adrenergic modifiers Angiotensin-converting enzyme (ACE) inhibitors Angiotensin II receptor blockers... read more . If blood pressure is not controlled adequately or if renal function deteriorates, PTA with stent placement or, when PTA is impossible, open surgical bypass or endarterectomy can improve blood flow.
Occlusion of the aortic bifurcation requires urgent embolectomy, usually done transfemorally. If chronic occlusion of the aortic bifurcation causes claudication, an aortoiliac or aortofemoral graft can be used to surgically bypass the occlusion. PTA is an alternative for selected patients.
Abdominal aortic branch occlusion can be acute or chronic.
Symptoms vary depending on the acuity of the occlusion and the artery involved.
Diagnose abdominal aortic branch occlusion based on history and physical examination and confirm with imaging tests.
Treat acute occlusion as a surgical emergency with embolectomy, percutaneous transluminal angioplasty, or surgical bypass. Treat chronic occlusion with drugs and lifestyle changes and, if severe, surgery or angioplasty.