Abdominal Aortic Aneurysms (Aaa)

An abdominal aortic diameter ? 3 cm represents an abdominal aortic aneurysm; The most common cause is atherosclerosis. Most aneurysms grow slowly, without causing symptoms, but some patients develop steady, deep pain in the lumbosacral region. The risk of rupture increases proportionally with the size of the aneurysm. The diagnosis is made by ultrasound or CT. The treatment is done through surgery or endovascular stent grafting.

Abdominal aortic aneurysms (AAA) account for about three-fourths of aortic aneurysms, affecting 0.5 to 3.2% of the population. The prevalence is three times higher in men. AAA typically begin below the renal arteries, but they may include disposals of the renal arteries; about 50% include the iliac artery a. Basically, an aortic diameter ? 3 cm means a AAA. Most AAA are fusiform, some are saccular. Many are characterized by laminated thrombi. AAA involve all layers of the wall of the aorta, but do not involve dissection; However, a thoracic aortic dissection may extend into the distal abdominal aorta.

An abdominal aortic diameter ? 3 cm represents an abdominal aortic aneurysm; The most common cause is atherosclerosis. Most aneurysms grow slowly, without causing symptoms, but some patients develop steady, deep pain in the lumbosacral region. The risk of rupture increases proportionally with the size of the aneurysm. The diagnosis is made by ultrasound or CT. The treatment is done through surgery or endovascular stent grafting. Abdominal aortic aneurysms (AAA) account for about three-fourths of aortic aneurysms, affecting 0.5 to 3.2% of the population. The prevalence is three times higher in men. AAA typically begin below the renal arteries, but they may include disposals of the renal arteries; about 50% include the iliac artery a. Basically, an aortic diameter ? 3 cm means a AAA. Most AAA are fusiform, some are saccular. Many are characterized by laminated thrombi. AAA involve all layers of the wall of the aorta, but do not involve dissection; However, a thoracic aortic dissection may extend into the distal abdominal aorta. Etiology The most common is an arterial wall weakness, which is usually caused by atherosclerosis. Other causes include trauma, vasculitis, cystic medial and postoperative Anastomosendehiszenz. Rarely weaken a syphilis and a localized bacterial infection or fungal infection, typically due to sepsis or infectious endocarditis, the arterial wall and cause infected (mycotic) aneurysms. Smoking is the most significant risk factor, other risk factors are hypertension, older age (peak incidence at the age of 70 to 80 years), family history (at 15 to 25%), race (more common in fair-skinned than in dark-skinned) and male gender. Abdominal aortic aneurysm var model = {thumbnailUrl: ‘/-/media/manual/professional/images/abdominal_aortic_aneurysm_02_high_blausen_de.jpg?la=de&thn=0&mw=350’ imageUrl: ‘/-/media/manual/professional/images/abdominal_aortic_aneurysm_02_high_blausen_de.jpg? lang = en & thn = 0 ‘, title:’ abdominal aortic aneurysm ‘description:’ ‘credits”, hideCredits: false, hideTitle: false, hideFigure: false, hideDescription: true}; var panel = $ (MManual.utils.getCurrentScript ()) Closest ( ‘image-element-panel.’). ko.applyBindings (model, panel.get (0)); Symptoms and signs Most are asymptomatic AAA. If symptoms and findings occur, they can be non-specific. When AAA expand, they can cause pain that is constant, drilling, visceral, and most felt in the lumbosacral region. Patients may be an abnormal eye-catching abdominal pulsation become aware. Rapidly enlarging aneurysms that are before the rupture, are often sensitive, but most aneurysms grow slowly without symptoms. The aneurysm may be palpable as a pulsatile mass or not. This depends on the size and habit of the patient. The probability that a patient with a pulsatile mass has a Anneurysma> 3 cm, is (positive predictive value) at about 40%. A systolic murmur can be heard above the aneurysm. In patients who die at the rupture of AAA immediately, arise typically present with abdominal pain or back pain, hypotension and tachycardia. You may recently an upper abdominal trauma, often minimal, or isometric tension have suffered (z. B. lifting a heavy object). Patients with occult AAA sometimes present themselves with symptoms of complications (eg. As pain in the extremities due to embolization of mural thrombi) or cause (eg. As fever, malaise and weight loss due to infection or vasculitis). Unusually large AAA cause disseminated intravascular coagulation, perhaps because large regions of pathologically altered endothelial surface trigger the fast thrombus formation and consumption of clotting factors. Diagnosis often randomly confirmed by ultrasound or CT Sometimes CT angiography or magnetic resonance angiography Most AAA are diagnosed by chance, if they are detected during physical examination or abdominal ultrasound, CT or MRI is performed for another reason. AAA should be considered in elderly patients considered that present with acute abdominal pain or back pain, regardless of whether a palpable pulsatile mass is present or not. If symptoms or physical examination can be a AAA suggests that abdominal ultrasound or CT is the investigation of choice. Symptomatic patients should be investigated immediately in order to make the diagnosis before the fatal rupture. In hemodynamically unstable patients with assumed rupture the bedside sonography provides faster results, but an intestinal gas accumulation and bloating may limit the validity. Laboratory tests incl. Blood count, electrolytes, urea, creatinine, prothrombin time, partial thromboplastin time and testing of blood type and crossmatch are performed in preparation for a possible operation. If no rupture is believed CT angiography (CTA) or MR angiography (MRA) may characterize the size and anatomy of the aneurysm in more detail. If thrombi fill the aneurysm wall, the CTA can underestimate the true size; CT without contrast can provide a more accurate estimate may. A aortography is essential when a participation of the renal arteries or aortoiliac disease is accepted or if the supply of endovascular stent-graft (endo-graft) is contemplated. X-Abomenübersichtsaufnahmen are neither sensitive nor specific; but if they are carried out due to other aspects that aortic calcification may be the aneurysm wall. If a mycotic aneurysm is suspected, blood cultures for bacteria and fungi should be removed. Therapy surgery or endovascular stent graft Some AAA enlarge at a constant rate (2-3 mm / year), some are increased exponentially, and 20% reserve for unknown reasons always the same size. The need for treatment depends on the size that is closely linked to the risk of rupture (see table: Abdominal aortic aneurysm size and risk of rupture *). Abdominal aortic aneurysms size and risk of rupture * AAA diameter (cm) of rupture (% / year) <4 0 4 to 4.9 from 5 to 5.9 1% * 5-10% 10-20% 6-6.9 7-7, 9 20-40% > 8 30-50% * Elective surgery should be considered when aneurysms> 5.0-5.5 cm into account. Ruptured AAAs require immediate open surgery or endovascular stent grafting. Without treatment, the mortality rate is almost 100%. With open surgical treatment, the mortality rate is about 50%; mortality in endovascular stent grafts in general is low (20 to 30%). The mortality rate is still so high because many patients have a coronary, cerebrovascular or peripheral atherosclerosis simultaneously. Patients who are admitted in hemorrhagic shock, requiring emergency care with hydration (intravenous fluid replacement: infusion solutions) and blood transfusions, but the mean arterial blood pressure should not be increased to> 70 to 80 mmHg, as otherwise may increase the bleeding. Preoperative setting of hypertension is important. Clinical Calculator: Mean vessel pressure (systemic or pulmonary) Tips and risks In a hypotonic patients with an AAA rupture of mean arterial blood pressure should not be increased to> 70 to 80 mmHg, as otherwise may increase the bleeding. An elective surgical care is recommended> 5-5.5 cm for aneurysms (because then the risk of rupture of> 5-10% / year) increases, except when accompanying diseases represent a contraindication for a surgical procedure. Additional indications for an elective surgical procedure include an increase in the size of the aneurysm of> 0.5 cm within six months regardless of the size one, moreover, chronic abdominal pain, thromboembolic complications and an aneurysm of the iliac or femoral artery, causing the ischemia of the lower leg. Before elective care clinical confirmation of coronary heart disease (CHD) essential (see table: Tests for the assessment of cardiac anatomy and function), as many patients with AAA have a generalized atherosclerosis and the surgical procedure is a major risk for cardiovascular events , An aggressive medical treatment and the control of risk factors are extremely important; revascularization should be considered only in patients with unstable coronary artery disease into consideration. It could not be shown that a routine preoperative coronary angioplasty or bypass surgery in most patients who are medically optimally prepared for an aneurysm repair is required. The surgical procedure consists of the replacement of the aneurysmal portion of the aorta with a synthetic graft (graft). If the iliac arteries are also affected, the graft must be extended so that it includes the iliac artery. If the aneurysm to more than expands the renal arteries, the renal arteries must be reimplanted into the graft or it must be created bypass grafts. Endovascular stent graft within the aneurysm lumen via the femoral artery is a less risky alternative and indicated where the risk of perioperative complications is high. This method excludes the aneurysm from systemic blood flow and reduces the risk of rupture. The aneurysm eventually thrombosed and 50% of aneurysms decrease in diameter. The short-term results are good, but the long-term results are unknown. The complications include angulation, kinking, thrombosis and migration of the stent graft and an endo-leak (persistent flow of blood into the aneurysm sac after placing the endovascular stent grafts) a. Therefore, during observations must be performed more frequently than with traditional surgical care after placement of endovascular stent graft. If no complications occur, imaging tests after 1, 6 and 12 months and then recommended once a year. A complex anatomy (eg. As a short neck aneurysm below the renal arteries, strong Arterienwindung) causes 30-40% of patients placement of endovascular stent-graft is difficult. The supply of aneurysms <5 cm does not seem to increase survival. These aneurysms should be monitored by ultrasound or every 6-12 months in terms of an increase in size, which requires treatment. It is important to control of atherosclerotic risk factors, v. a. it is important to quit smoking, and as recommended taking antihypertensive therapy. The risk of rupture compared to the perioperative risk of complications should be discussed openly with the patient. If a small or medium-sized aneurysm> 5.5 cm in size and the risk of perioperative complications is lower than the estimated risk of rupture, the surgery is indicated. Treating a mycotic aneurysm consists in a vigorous anti-microbial therapy, which is specified by the pathogen, followed by the excision of the aneurysm. Early diagnosis and treatment improve results. Key points An abdominal aortic diameter ? 3 cm means an AAA. AAA increases typically at a constant rate, but larger, some AAA itself exponentially and 20% always keep the same size. The risk of rupture increases proportionally with the size of the aneurysm. The diagnosis is made by ultrasound or CT. Aneurysm rupture without CT angiography or MR angiography can characterize the size and anatomy of the aneurysm more accurately. Ruptured AAAs require immediate open surgery or endovascular stent grafting. An elective surgical care is for aneurysms> 5 to 5.5 cm and those they increase rapidly or cause ischemic or embolic complications, recommended.

Health Life Media Team

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