Aortic aneurysm
779059
226069152
2008-07-16T18:13:23Z
198.133.139.5
{{Infobox_Disease
| Name = Aortic aneurysm
| Image =
| Caption =
| DiseasesDB = 792
| DasesDB_mult = {{DiseasesDB2|823}} {{DiseasesDB2|805}}
| ICD10 = {{ICD10|I|71||i|70}}
| ICD9 = {{ICD9|441}}
| ICDO =
| OMIM = 100070
| MedlinePlus =
| eMedicineSubj = emerg
| eMedicineTopic = 942
| eMedicine_mult = {{eMedicine2|med|2783}} {{eMedicine2|emerg|27}} {{eMedicine2|radio|1}} {{eMedicine2|med|3443}}
| MeshID = D001014
}}
An '''aortic aneurysm''' is a general term for any swelling ('''dilatation''' or [[aneurysm]]) of the [[aorta]], usually representing an underlying weakness in the wall of the aorta at that location. While the stretched vessel may occasionally cause discomfort, a greater concern is the risk of '''rupture,''' which causes severe pain; massive internal [[hemorrhage]]; and, without prompt treatment, results in a quick death.
==Classification==
Aortic aneurysms are classified by where on the aorta they occur; aneurysms can appear anywhere. An '''aortic root aneurysm''', or [[aneurysm of sinus of Valsalva]], appears on the [[sinuses of Valsalva]] or aortic root. [[Thoracic aortic aneurysm]]s are found on the [[thoracic aorta]]; these are further classified as '''ascending''', '''aortic arch''', or '''descending''' aneurysms depending on the location on the thoracic aorta involved. [[Abdominal aortic aneurysm]]s, the most common form of aortic aneurysm, are found on the [[abdominal aorta]], and '''thoracoabdominal aortic aneuryms''' involve both the thoracic and abdominal aorta.
==Pathology==
The physical change in the aortic diameter can occur secondary to an intrinsic defect in the protein construction of the aortic wall, trauma, infection, or due to progressive destruction of aortic proteins by enzymes.
==Signs, symptoms and diagnosis==
{{Cleanup-section|date=March 2008}}
Most intact aortic aneurysms do not produce symptoms. As they enlarge, symptoms such as [[abdominal pain]] and [[back pain]] may develop. Compression of nerve roots may cause leg pain or numbness. Untreated, aneurysms tend to become progressively larger, although the rate of enlargement is unpredictable for any individual. Rarely, clotted blood which lines most aortic aneurysms can break off and result in an [[Embolism|embolus]]. They may be found on physical examination. Medical imaging is necessary to confirm the diagnosis. Symptoms may include: anxiety or feeling of stress; nausea and vomiting; clammy skin; rapid heart rate.<ref>{{cite web|url=http://www.rush.edu/rumc/page-1160429744171.html|title=Rush University Medical Center|accessdate=2008-03-12}}</ref>
===Abdominal aortic aneurysm===<!-- This section is linked from [[List of medical abbreviations]] -->
{{main|Abdominal aortic aneurysm}}
Abdominal aortic aneurysms, hereafter referred to as AAAs, are the most common type of aortic aneurysm. One reason for this is that [[elastin]], the principal load-bearing protein present in the wall of the aorta, is reduced in the abdominal aorta as compared to the thoracic aorta (nearer the heart). Another is that the abdominal aorta does not possess [[vasa vasorum]], hindering repair. Most are ''true aneurysms'' that involve all three layers ([[tunica intima]], [[tunica media]] and [[tunica adventitia]]), and are generally asymptomatic before rupture.
The prevalence of AAAs increases with age, with an average age of 65-70 at the time of diagnosis. AAAs have been attributed to [[atherosclerosis]], though other factors are involved in their formation.
An AAA may remain asymptomatic indefinitely. There is a large risk of rupture once the size has reached 5 cm, though some AAAs may swell to over 15 cm in diameter before rupturing. Before rupture, an AAA may present as a large, pulsatile mass above the [[umbilicus]]. A [[bruit]] may be heard from the turbulent flow in a severe atherosclerotic aneurysm or if thrombosis occurs. Unfortunately, however, rupture is usually the first hint of AAA. Once an aneurysm has ruptured, it presents with a classic [[pain]]-[[hypotension]]-[[mass]] triad. The pain is classically reported in the abdomen, back or flank. It is usually acute, severe and constant, and may radiate through the abdomen to the back.
The diagnosis of an abdominal aortic aneurysm can be confirmed at the bedside by the use of [[medical ultrasonography|ultrasound]]. Rupture could be indicated by the presence of free fluid in potential abdominal spaces, such as [[Morrison's pouch]], the [[splenorenal space]], [[subdiaphragmatic spaces]] and peri-vesical spaces. A contrast-enhanced abdominal [[computed tomography|CT scan]] is needed for confirmation.
Only 10-25% of patients survive rupture due to large pre- and post-operative mortality. Annual mortality from ruptured abdominal aneurysms in the [[United States]] alone is about 15,000. Another important complication of AAA is formation of a [[thrombus]] in the aneurysm.
==Screening==
{{main|Abdominal aortic aneurysm#Screening}}
==Medical treatment==
Medical therapy of aortic aneurysms involves strict [[blood pressure]] control. This does not treat the aortic aneurysm per se, but control of [[hypertension]] within tight blood pressure parameters may decrease the rate of expansion of the aneurysm.
===Surgical treatment===
The definitive treatment for an aortic aneurysm is surgical repair of the aorta. This typically involves opening up of the dilated portion of the aorta and insertion of a synthetic ([[Dacron]] or [[Gore-tex]]) patch tube. Once the tube is sewn into the proximal and distal portions of the aorta, the aneurysmal sac is closed around the artificial tube. Instead of sewing, the tube ends, made rigid and expandable by [[nitinol]] wireframe, can be much more simply and quickly inserted into the vascular stumps and there permanently fixed by external ligature <ref>Tex Heart Inst J. 2002;29(1):56-9</ref>[http://www.fondazionecarrel.org/sp/sp.html]
The determination of when surgery should be performed is complex and case-specific. The overriding consideration is when the risk of rupture exceeds the risk of surgery. The diameter of the aneurysm, its rate of growth, the presence or absence of [[Marfan Syndrome]] or similar connective tissue disorders, and other coexisting medical conditions are all important factors in the determination.
A rapidly expanding aneurysm should be operated on as soon as feasible, since it has a greater chance of rupture. Slowly expanding aortic aneurysms may be followed by routine diagnostic testing (ie: [[CT scan]] or [[ultrasound]] imaging). If the aortic aneurysm grows at a rate of more than 1 cm/year, surgical treatment should be electively performed.
The current treatment guidelines for abdominal aortic aneurysms suggest elective surgical repair when the diameter of the aneurysm is greater than 5 cm. However, recent data suggests medical management for abdominal aneurysms with a diameter of less than 5.5 cm.<ref>Mortality results for randomised controlled trial of early elective surgery or ultrasonographic surveillance for small abdominal aortic aneurysms. The UK Small Aneurysm Trial Participants. Lancet. 1998 Nov 21;352(9141):1649-55. ([http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=9853436 Medline abstract])</ref>
===Endovascular treatment of AAA===
In the recent years, the endoluminal treatment of Abdominal Aortic Aneurysms has emerged as a minimally invasive alternative to open surgery repair. The first endoluminal exclusion of an aneurysm took place in Argentina by Dr. Parodi and his colleagues in 1991. The endovascular treatment of aortic aneurysms involves the placement of an endo-vascular [[stent]] via a [[percutaneous]] technique (usually through the femoral arteries) into the diseased portion of the aorta. This technique has been reported to have a lower mortality rate compared to open surgical repair, and is now being widely used in individuals with co-morbid conditions that make them high risk patients for open surgery. Some centers also report very promising results for the specific method in patients that do not constitute a high surgical risk group.
There have also been many reports concerning the endovascular treatment of ruptured Abdominal Aortic Aneurysms, which are usually treated with an open surgery repair due to the patient's impaired overall condition. Mid-term results have been quite promising.{{Fact|date=July 2007}} However, according to the latest studies, the [[EVAR]] procedure doesn't carry any overall survival benefit.<ref>[http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=abstractplus&list_uids=16782510&query_hl=9&itool=pubmed_docsum Rutherford RB.: Randomized EVAR Trials and Advent of Level I Evidence: A Paradigm Shift in Management of Large Abdominal Aortic Aneurysms? (abstract)] Semin Vasc Surg. 2006 Jun;19(2):69-74. PMID: 16782510</ref>
===Endovascular treatment of other aortic aneurysms===
The endoluminal exclusion of aortic aneurysms has seen a real revolution in the very recent years. It is now possible to treat thoracic aortic aneurysms, abdominal aortic aneurysms and other aneurysms in most of the body's major arteries (such as the iliac and the femoral arteries) using endovascular stents and avoiding big incisions. Still, in most cases the technique is applied in patients at high risk for surgery as more trials are required in order to fully accept this method as the gold standard for the treatment of aneurysms.
===Prevention===
Attention to patient's general blood pressure, smoking and [[cholesterol]] risks helps reduce the risk on an individual basis. There have been proposals to introduce [[ultrasound scan]]s as a screening tool for those most at risk: men over the age of 65.<ref>Routine screening in the management of AAA, UK Department of Health study [http://www.dh.gov.uk/PolicyAndGuidance/ResearchAndDevelopment/ResearchAndDevelopmentAZ/CardiovascularDiseaseAndStroke/CardiovascularDiseaseAndStrokeArticle/fs/en?CONTENT_ID=4002152&chk=/9i9J2 Report]</ref> <ref>Abdominal Aortic Aneurysm screening, a review by Bandolier, a UK independent source of evidence-based healthcare information for both healthcare professionals and consumers. Bandolier 27-3 [http://www.jr2.ox.ac.uk/bandolier/band27/b27-3.html Article]</ref>. The tetracycline antibiotic [[Doxycycline]] is currently being investigated for use as a potential drug in the prevention of aortic aneurysm due to its metalloproteinase inhibitor and collagen stabilising properties.
===Research===
Stanford University is conducting research to gather information on AAA risk factors, and to evaluate the effectiveness of an exercise program at preventing the growth of small AAAs in older individuals.[http://aaastop.stanford.edu/]
==See also==
* [[Aortic dissection]]
==References==
{{reflist}}
===Bibliography===
#Saratzis N., Melas N., Lazaridis J., Ginis G., Antonitsis P., Lykopoulos D., Lioupis A., Gitas C., Kiskinis D. "Endovascular AAA repair with the aortomonoiliac EndoFit stent-graft: two years' experience." J Endovasc Ther. 2005 Jun;12(3):280-7
===External links===
* [http://www.aortarepair.com Aortic Aneurysm Center]
* [http://www.lombardmedical.com lombard medical]
{{Vascular diseases}}
[[Category:Vascular surgery]]
[[de:Aortenaneurysma]]
[[es:Aneurisma de aorta]]
[[it:Aneurisma aortico]]
[[pl:Tętniak aorty]]
[[fi:Aortta-aneurysma]]