AAA is uncommon in individuals of African, African American, Asian and Hispanic heritage. The frequency rate varies strongly between males and females. The peak incidence is among males around 70 years of age, the prevalence among males over 60 years totals 2-6%. The frequency is much higher in smokers than in non-smokers (8:1). Other risk factors include hypertension and male sex.[3] In the US, the incidence of AAA is 2-4% in the adult population. [4]. Rupture of the AAA occurs in 1-3% of men aged 65 or more, the mortality is 70-95%[5].
Manifestations and Diagnosis
AAAs are commonly divided according to their size and symptomatology. The aneurysm is usually considered to be present if the measured outer aortic diameter is over 3 cm (normal diameter of aorta is around 2 cm). If the outer diameter exceeds 5 cm, the aneurysm is considered to be large. Small aneurysms under 5 cms don't have such a big tendency to rupture and are usually treated conservatively.[3][5] The vast majority of aneurysms are asymptomatic. The risk of rupture is high in a symptomatic aneurysm, which is therefore considered an indication for surgery. Possible symptoms include low back pain, flank pain, abdominal pain, groin pain or pulsating abdominal mass.[7] The complications include rupture, peripheral embolisation, acute aortic occlusion, aortocaval or aortoduodenal fistulae. On physical examination, a palpable abdominal mass can be noted. Bruits can be present in case of renal or visceral arterial stenosis.[4]
The diagnosis consists of 2 steps - screening and assessment of severity. As most of the AAAs are asymptomatic, their presence is usually revealed during an abdominal examination for another reason - the most common being abdominal ultrasonography. Skilled physicians can also suspect the presence of the AAA from abdominal palpation. Ultrasonography provides the initial assessment of the size and extent of the aneurysm. The subsequent examinations include CT, MRI and special modes thereof, like CT/MR angiography. Although non-invasive imaging methods now prevail in the diagnostics of AAA, angiography remains the diagnostic standard for AAA, and can be ordered to assess the degree of renal / visceral involvement, or in case of renal abnormality.
Treatment
There are currently three modes of treatment available for the AAA: conservative, open aneurysm repair (OR), and endovascular aneurysm repair (EVAR).
- Conservative treatment is indicated in patients with small asymptomatic aneurysms and in high-risk patients. The two mainstays of the conservative treatment are smoking cessation and blood pressure control.
- Open repair (operation) is indicated in young patients as an elective procedure, or in growing or large, symptomatic or ruptured aneurysms.
- Endovascular repair is indicated in older, high-risk patients or patients unfit for open repair. However, according to the latest studies, the EVAR procedure doesn't offer any overall survival benefit.[8]
Segmental pressure measurements are blood pressure measurements taken at multiple levels on the leg. Further from the heart, lower the pressure.
How is this test given?
It is similar to the ABI test, with the addition of two or three additional blood pressure cuffs. These additional cuffs are placed just below the knee and one large cuff or two narrow cuffs are placed above the knee and at the upper thigh. These cuffs are then inflated above your normal systolic blood pressure, and then slowly deflated.
Using the Doppler instrument, blood pressure measurements are taken. The blood pressure at each cuff location on your leg is noted in your physician's report. A significant drop in pressure between two adjacent cuffs indicates a narrowing of the artery or blockage along the arteries in this portion of your leg. This allows the vascular technologist and doctor to identify more precisely the location of such blockages in the arteries of your leg.
-----------------------------------------------------------Claudication, literally 'limping', is used as a medical term in various contexts. It is also used figuratively.
Claudication refers to cramplike pains in the calves caused by poor circulation of the blood to the leg muscles.
Jaw claudication is pain in the jaw or ear while chewing. The most commonly used application of claudication is to describe the pain in the legs on exertion suffered by arteriopaths. The lack of compliance of the arterial tree, usually due to atherosclerosis, means that on exertion the body is unable to compensate and increase blood flow. This causes severe cramping pain, usually in the calf muscles, which will only be relieved by rest.
Spinal claudication is not due to lack of blood supply, but is instead the pain felt on exertion by patients whose leg pain is caused by nerve root compression, usually from a degenerative spine. It may be differentiated from arterial claudication in that it is often only relieved by sitting down, whereas in arterial claudication standing at rest is usually sufficient to relieve the pain.
The ankle-brachial index is a simple, non-invasive test that can be used to assess patients with claudication symptoms. The ankle-brachial index, or ABI, involves obtaining blood pressure measurements in both arms and both legs. The higher of the two arm pressures becomes the denominator, and the individual leg or ankle pressures serve as the numerator in calculating the ABI for each leg. Thus the ABI is a ratio which roughly compares the blood flow in the arms to that in the legs, and can help screen for arterial insufficiency as a source of the claudication symptoms. A normal ABI should be 1.0-1.3, whereas an ABI of less than 0.9 can indicate significant arterial insufficiency. An ABI of less than 0.5-0.6 can correlate with threatened limb loss. An abnormal ABI in correspondence with claudication symptoms usually leads to a more sophisticated imaging work-up to uncover the specific arterial blockages implied by the screening test.
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Atherosclerosis is a disease affecting the arterial blood vessel. It is commonly referred to as a "hardening" or "furring" of the arteries. It is caused by the formation of multiple plaques within the arteries.
Pathologically, the atheromatous plaque is divided into three distinct components:
- The atheroma ("lump of porridge", from Athera, porridge in Greek,) is the nodular accumulation of a soft, flaky, yellowish material at the center of large plaques, composed of macrophages nearest the lumen of the artery, sometimes with
- Underlying areas of cholesterol crystals, and possibly also
- Calcification at the outer base of older/more advanced lesions.
The following terms are similar, yet distinct, in both spelling and meaning, and can be easily confused: arteriosclerosis, arteriolosclerosis and atherosclerosis. Arteriosclerosis, is a general term describing any hardening (and loss of elasticity) of medium or large arteries (in Latin, Arterio meaning artery and sclerosis meaning hardening), arteriolosclerosis is arteriosclerosis mainly affecting the arterioles (small arteries), atherosclerosis is a hardening of an artery specifically due to an atheromatous plaque (in Latin, "athero" means "porridge"). Therefore, atherosclerosis is a form of arteriosclerosis.
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Arteriosclerosis ("hardening of the artery") results from a deposition of tough, rigid collagen inside the vessel wall and around the atheroma. This increases the stiffness, decreases the elasticity of the artery wall. Arteriolosclerosis (hardening of small arteries, the arterioles) is the result of collagen deposition, but also muscle wall thickening and deposition of protein ("hyaline").
Calcification, sometimes even ossification (formation of complete bone tissue) occurs within the deepest and oldest layers of the sclerosed vessel wall.
Atherosclerosis causes two main problems. First, the atheromatous plaques, though long compensated for by artery enlargement, eventually lead to plaque ruptures and stenosis (narrowing) of the artery and, therefore, an insufficient blood supply to the organ it feeds. Alternatively, if the compensating artery enlargement process is excessive, then a net aneurysm results.
These complications are chronic, slowly progressing and cumulative. Most commonly, soft plaque suddenly ruptures (see vulnerable plaque), causing the formation of a blood clot (thrombus) that will rapidly slow or stop blood flow, e.g. 5 minutes, leading to death of the tissues fed by the artery. This catastrophic event is called an infarction. One of the most common recognized scenarios is called coronary thrombosis of a coronary artery causing myocardial infarction (a heart attack). Another common scenario in very advanced disease is claudication from insufficient blood supply to the legs, typically due to a combination of both stenosis and aneurysmal segments narrowed with clots. Since atherosclerosis is a body wide process, similar events also occur in the arteries to the brain, intestines, kidneys, legs, etc.
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Horseshoe kidney is a congenital disorder, affecting about 1 in 500 to 1 in 600 people, in which a person's two kidneys fuse together to form a horseshoe-shape. This is the most common type of fusion anomaly in the kidneys. American actor Mel Gibson has this disorder.
The kidney ends up inferior to the inferior mesenteric artery, since its embryological ascent is arrested by its presence.
Because it causes no symptoms or other problems, it could be argued whether this condition is a 'disease'. It may, however, present problems for doctors who attempt to interpret diagnostic images or perform operations without being aware that the patient has it. Also, a surgeon may have to proceed in an unusual fashion to avoid the kidney(s).
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In medicine, ischemia (Greek ισχαιμία, isch- is restriction, hema or haema is blood) is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia.
Rather than in hypoxia, a more general term denoting a shortage of oxygen (usually a result of lack of oxygen in the air being breathed), ischemia is an absolute or relative shortage of the blood supply to an organ. Relative shortage means the mismatch of blood supply (oxygen delivery) and blood request for adequate oxygenation of tissue.
Ischemia can also be described as an inadequate flow of blood to a part of the body, caused by constriction or blockage of the blood vessels supplying it. Ischemia of heart muscle produces angina pectoris.
This can be due to:
- Tachycardia (abnormally rapid beating of the heart)
- Atherosclerosis (lipid-laden placques obstructing the lumen of arteries)
- Hypotension (low blood pressure, e.g. in septic shock, heart failure)
- Thromboembolism (blood clots)
- Outside compression of a blood vessel, e.g. by a tumor
- Foreign bodies in the circulation (e.g. amniotic fluid in amniotic fluid embolism)
- Sickle cell disease (abnormally shaped hemoglobin)
In medicine, anastomosis is the surgical connection of two structures.[2] It commonly refers to connections between blood vessels or connections between other tubular structures such as a loops of intestine. For example, when a segment of intestine is resected, the two remaining ends are sewn or stapled together (anastomosed), and the procedure is referred to as an intestinal anastomosis.
Circulatory anastomoses
Anastomoses occur normally in the body in the circulatory system, serving as backup routes for blood to flow if one link is blocked or otherwise compromised. There are many examples of these in the body. However clinically important examples include:
- Circle of Willis (in the brain)
- scapular anastomosis (for the subclavian vessels)
- joint anastomoses - clinically very important. Almost all joints receive anastomotic blood supply from more than one source. Examples include knee (and geniculate arteries), shoulder (and circumflex humeral), hip (and circumflex iliac) and ankle.
- pelvic anastomoses
- abdominal anastomoses
- hand and foot anastomoses (which include the palmar and plantar arches)
- Coronary: anterior and posterior interventricular arteries of the heart
In surgical jargon, to create an anastomosis is to stitch together two cut ends of any hollow organ, usually to restore continuity after resection, or to bypass an unresectable disease process.
Anastomosis are typically performed on:
- Blood vessels: Arteries and veins. Most vascular procedures, including all arterial bypass operations (e.g. coronary artery bypass), aneurysmectomy of any type, and all solid organ transplants require vascular anastomoses.
- Gastrointestinal (GI) tract: Esophagus, stomach, small bowel, large bowel, bile ducts and pancreas. Virtually all elective resections of gastrointestinal organs are followed by anastomoses to restore continuity; pancreaticoduodenectomy is considered a massive operation, in part, because it requires three separate anastomoses (stomach, biliary tract and pancreas to small bowel). Bypass operations on the GI tract, once rarely performed, are the cornerstone of bariatric surgery. The widespread use of mechanical sutring devices (linear and circular staplers) changed the face of gastrointestinal surgery.
- Urinary tract: Ureters, urinary bladder, urethra. Radical prostatectomy and radical cystectomy both require anastomosis of the bladder to the urethra in order to restore continuity.
- Microsurgery: The advent of microsurgical technique allowed anastomoses previously thought impossible, such as so-called "nerve anastomoses" (not strictly an anastomosis according to the above definition), and operations to restore fertility after tubal ligation or vasectomy.
One entry found for patency. Main Entry: pa·ten·cy
Pronunciation:
pat-
n-s
, p
t-Function: noun
Inflected Form(s): plural -cies
: the quality or state of being open or unobstructed
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Gangrene caused by a serious bacterial infection is called wet gangrene.
Gangrene caused by lack of circulation in an injured or diseased area is called dry gangrene.
