Carotids

Carotids

What is carotid artery disease?

Carotid artery disease occurs when the major arteries in your neck become narrowed or blocked. These arteries, called the carotid arteries, supply your brain with blood. Your carotid arteries extend from your aorta in your chest to the brain inside your skull.

You are more likely to develop carotid artery disease as you age. Only 1 percent of adults age 50 to 59 have significantly narrowed carotid arteries, but 10 percent of adults age 80 to 89 have this problem.

Your arteries are normally smooth and unobstructed on the inside, but as you age, a sticky substance called plaque can build up in the walls of your arteries. Plaque is made up of cholesterol, calcium, and fibrous tissue. As more plaque builds up, your arteries narrow and stiffen. This process is called atherosclerosis, or hardening of the arteries. Eventually, when enough plaque builds up to reduce blood flow through your carotid arteries, physicians call this carotid artery disease. Carotid artery disease is a serious health problem because it can cause a stroke.

Some plaque deposits are soft and are prone to cracking or forming roughened, irregular areas inside the artery. If this happens, your body will respond as if you were injured and flood the cracked and irregular area with blood-clotting cells called platelets. A large blood clot may then form in your carotid artery or one of its branches. If the clot blocks the artery enough to slow or stop blood and oxygen flow to your brain, it could cause a stroke. More commonly, a piece of the plaque itself, or a clot, breaks off from the plaque deposit and travels through your bloodstream. This particle can then lodge in a smaller artery in your brain and cause a stroke by blocking the artery.

Fortunately, you may be able to prevent or slow carotid artery disease. Quitting smoking is the most important change you can make to avoid this disease. Other ways to prevent carotid artery disease include:

	•	Exercising regularly
	•	Eating a healthy diet
	•	Maintaining a healthy weight

Controlling factors that increase your chances of developing carotid artery disease, such as diabetes, high blood pressure, or high cholesterol, also help prevent the disease. 

What are the symptoms?

Carotid artery disease may not cause symptoms in its early stages.

Unfortunately, the first sign of carotid artery disease could be a stroke. However, you may experience warning symptoms of a stroke called transient ischemic attacks, or TIAs. Symptoms of a TIA usually last for a few minutes to 1 hour and include:

	•	Feeling weakness, numbness, or a tingling sensation on one side of your body, for example, in an arm or a leg
	•	Being unable to control the movement of an arm or a leg
	•	Losing vision in one eye (many people describe this sensation as a window shade coming down)
	•	Being unable to speak clearly

These symptoms usually go away completely within 24 hours. However, you should not ignore them. Having a TIA means that you are at serious risk of a stroke in the near future. You should report TIA symptoms to your physician immediately.

If you experience the above symptoms for longer than a few hours, or they don't resolve within 24 hours, a stroke has probably occurred. You should contact your physician immediately.

What causes carotid artery disease?

Hardening of the arteries causes most cases of carotid artery disease.

Experts do not fully understand the cause of hardening of the arteries. Plaque may build up in the arteries because of an injury to the artery's inner lining. Factors that injure artery walls include smoking, high cholesterol, and high blood pressure.

In rare cases, conditions known as carotid aneurysm disease and fibromuscular dysplasia cause carotid artery disease.

Other factors that may increase your chances of developing carotid artery disease include diabetes and having a family history of hardening of the arteries.

What tests will I need?

First your physician asks you questions about your general health, medical history, and symptoms. In addition, your physician conducts a physical exam. Together these are known as a patient history and exam. As part of your history and exam, your physician will ask you if you smoke or have high blood pressure. Your physician will also want to know when your symptoms occur and how often.

During your exam, your physician will listen for sounds of turbulent blood flow in your carotid arteries. He or she may also measure your blood pressure.

After the history and exam, if your physician suspects you have carotid artery disease, he or she will perform a carotid duplex ultrasound. In this test, a technician holds a small ultrasound probe to your neck. The probe emits high-frequency sound waves that bounce off of blood cells and blood vessels to show blood flow and problems with the structure of blood vessels. This test can show your physician how open your carotid arteries are and how quickly blood flows through them.

Carotid duplex ultrasound detects most cases of carotid artery disease. Therefore, your physician may not need to perform other tests. However, if ultrasound does not provide enough information, your physician may order one or more of the following:

•	CT scan: CT scans take x ray pictures of slices of the brain. CT scans can indicate carotid artery disease by showing an area of the brain that has poor blood flow. Your physician may inject a contrast dye to make blood vessels appear on the x ray
•	Magnetic resonance angiography (MRA): MRA uses radio waves and magnetic fields to create detailed images. Some forms of this test can show moving blood flow and may help evaluate carotid artery disease. To improve the test's accuracy, physicians sometimes inject a material called gadolinium to make the arteries more visible
•	Angiography: In this test, your physician injects a contrast dye into your arteries and then takes x rays. The structure of your arteries appears on the x ray because x rays cannot pass through the dye. This test shows how blood flows through the arteries and whether they are narrowed. Angiography carries some risks, including a small incidence of stroke, which is one reason that physicians do not always use it to diagnose carotid artery disease. Vascular surgeons also use angiography during carotid angioplasty and stenting, which is discussed later in this article

 

How is carotid artery disease treated?

Your treatment will depend on the severity of your condition, as well as your general health. As a first step, your vascular surgeon may recommend medications and the lifestyle changes discussed later in this article.

If you have any other medical conditions, make sure to follow your physician's instructions to manage them. For example, if you have diabetes, be sure to monitor and control your blood sugar levels. If you have high blood pressure, your physician may prescribe medications to lower it. Have your physician check your cholesterol levels regularly to be sure they stay within normal limits. Your physician may prescribe medications such as statins to reduce high cholesterol.

Surgery

You may require surgery if your carotid artery disease is severe or has progressed. Signs of severe disease include having TIA symptoms, having experienced a stroke in the past, or just having a severely narrowed carotid artery even without symptoms.

During surgery, your vascular surgeon removes plaque that is blocking your carotid artery. The procedure is called carotid endarterectomy. A vascular surgeon makes an incision in your neck and then removes the plaque contained in the inner lining of your carotid artery. This procedure removes the plaque and leaves a smooth, wide-open artery. You may be able to leave the hospital the same day or the day after the procedure depending upon how you feel. This procedure is safe and long lasting when done by a qualified vascular surgeon in the proper circumstances.

Angioplasty and stenting

A newly developed minimally invasive procedure to treat carotid artery disease is angioplasty and stenting. To perform this procedure, your vascular surgeon may insert a long, thin tube called a catheter through a small puncture site over a groin artery and guide it through your blood vessels to your carotid artery. The catheter carries a tiny balloon that inflates and deflates, flattening the plaque against the walls of the artery. Next, the physician places a tiny metal-mesh tube called a stent in the artery to hold it open. Your hospital stay after angioplasty and stenting is approximately the same as with endarterectomy. Carotid angioplasty and stenting is currently controversial because long-term results are not yet available. Nevertheless, for patients who have medical conditions that increase the risk of carotid endarterectomy, angioplasty and stenting may be a good alternative.

What can I do to stay healthy?

If you do not require surgery, make sure you and your immediate family members understand the warning signs of TIA. Follow your physician's instructions for any prescribed medications, and return for any scheduled follow up tests.

Changing some lifestyle factors may limit the progression of your carotid artery disease. The first step smokers should take is to quit smoking. Other changes that can decrease your risk of carotid artery disease include losing weight, exercising regularly, and eating a diet low in saturated fats

Aorta

Aorta

The aorta is the main artery from which all organs in the body receive their arterial blood supply. Arterial blood contains oxygen and other nutrients. This is delivered to the various organs by means of the heart that pumps blood through the arteries to the organs.

Aortic Aneurysm:

What is abdominal aortic aneurysm (AAA)?

The aorta is the largest artery in your body,and it carries blood away from your heart. Your aorta runs through your chest, where it is called the thoracic aorta. When it reaches your abdomen, it is called the abdominal aorta. The abdominal aorta supplies blood to the lower part of the body. Just below the abdomen, the aorta splits into two branches that carry blood into each leg.

When a weak area of the abdominal aorta expands or bulges, it is called an abdominal aortic aneurysm (AAA). The pressure from blood flowing through your abdominal aorta can cause a weakened part of the aorta to bulge, much like a balloon. A normal aorta is about 1 inch in diameter. However, AAA can stretch the aorta beyond its safety margin. Aneurysms are a health risk because they can burst, or rupture. A ruptured aneurysm can cause severe internal bleeding, which can lead to shock or even death.

AAA can cause another serious health problem. Clots or debris can form inside the aneurysm and travel to blood vessels leading to other organs in your body. If one of these blood vessels becomes blocked, it can cause severe pain or even more serious problems, such as limb loss.

Each year, physicians diagnose approximately 200,000 people in the United States with AAA. Of those 200,000, nearly 15,000 may have AAA threatening enough to cause death from a ruptured aneurysm if not treated.

Fortunately, when diagnosed early, AAA can be treated, or even cured, with highly effective and safe treatments.

What are the symptoms?

Although you may not feel any symptoms with AAA, if you develop symptoms, you may experience one or more of the following:

	•	A pulsing feeling in your abdomen, similar to a heartbeat
	•	Severe, sudden pain in your abdomen or lower back. If this is the case, your aneurysm may be about to burst

If your aneurysm bursts, you may suddenly feel intense weakness, dizziness, or pain, and you may lose consciousness. This is a life-threatening situation and you should seek medical attention immediately.

What causes an abdominal aortic aneurysm?

Physicians and researchers are not quite sure what causes AAA. The leading thought is that the aneurysm may be caused by inflammation in the aorta, which may cause its wall to break down. Some researchers believe that this inflammation can be associated with atherosclerosis (also called hardening of the arteries) or risk factors that contribute to atherosclerosis, such as high blood pressure (hypertension). In atherosclerosis fatty deposits, called plaque, build up in an artery. Over time, this buildup causes the artery to narrow, stiffen and possibly weaken.Besides atherosclerosis, other factors that can increase your risk of AAA include:

	•	Being a man older than 60 years
	•	Having an immediate relative, such as a mother or brother, who has had AAA
	•	Having high blood pressure
	•	Smoking

Your risk of developing AAA increases as you age. AAA is more common in men than in women.

What tests will I need?

Abdominal aortic aneurysms are most often found when a physician is performing an imaging test, such as an ultrasound, for another condition. If your physician suspects that you may have AAA, he or she may recommend one of the following tests:

	•	Abdominal ultrasound
	•	Computed tomography (CT) scan
	•	Magnetic resonance imaging (MRI)

How is an abdominal aortic aneurysm treated?

Watchful waiting

Your physician may recommend "watchful waiting," which means that you will be monitored every 6 months for signs of changes in the aneurysm. Your physician may schedule you for regular CT scans or ultrasounds to watch the aneurysm. This method is usually used for aneurysms that are smaller than 2 inches. If you also have high blood pressure, your physician may prescribe blood pressure medication to lower your blood pressure and lower the pressure on the weakened area of the aneurysm.

Surgical aneurysm repair

A vascular surgeon may recommend that you have a surgical procedure called open aneurysm repair if your aneurysm is causing symptoms or is larger than 2 inches, or is enlarging under observation. During an open aneurysm repair, also known as surgical aneurysm repair, your surgeon makes an incision in your abdomen and replaces the weakened part of your aorta with a tube-like graft. This graft is made of man-made material, such as plastic, in the size and shape of the healthy aorta. The tube strengthens your aorta and allows blood to pass easily through it. Following the surgery, you may stay in the hospital for 5 to 10 days. You may also require 2 to 3 months for a complete recovery. More than 90 percent of open aneurysm repair are successful for the long term.

Endovascular stent graft

Instead of open aneurysm repair, your vascular surgeon may consider a newer procedure called an endovascular stent graft. Endovascular means that the treatment is performed inside your body using long, thin tubes called catheters that are threaded through your blood vessels. This procedure is less invasive, meaning that your surgeon will make only small incisions in your groin area through which to thread the catheters. During the procedure, your surgeon will use live xray pictures on a video screen to guide a fabric and metal tube, called a graft, to the site of aneurysm. Like the graft in open surgery, the endovascular stent graft also strengthens the aorta. Your recovery time for endovascular stent graft is much shorter than surgery, and your hospital stay is reduced to 2 to 3 days. However, this procedure is more likely to require periodic maintenance than the open procedure. In addition, you may not be suitable to have this procedure, since not all patients are candidates for endovascular repair. In some cases, open aneurysm repair may be the best way to cure AAA.

Aortic Occlusive Disease:

Some patients develop occlusion of the abdominal aorta and its end branches, named the iliac arteries. Patients often complain of difficulty when walking (claudication). This problem can be resolved by means of a bypass procedure.

What is aortoiliac occlusive disease?

Aortoiliac occlusive disease occurs when your iliac arteries become narrowed or blocked. The aorta, your body's main artery, splits into branches at about the level of your belly button. These branches are called the iliac arteries. The iliac arteries go through your pelvis into your legs, where they divide into many smaller arteries that run down to your toes. Aortoiliac disease is considered a type of peripheral arterial disease (PAD), because it affects arteries that carry blood away from your heart to your limbs.

Your arteries are normally smooth and unobstructed on the inside, but as you age, a sticky substance called plaque can build up in the walls of your arteries. Plaque is made up of cholesterol, calcium, and fibrous tissue. As more plaque builds up, it causes your arteries to narrow and stiffen. This process is called atherosclerosis, or hardening of the arteries. Eventually, enough plaque builds up to interfere with blood flow in your iliac arteries or leg arteries. Physicians call this aortoiliac occlusive disease.

When your iliac arteries narrow or become blocked, your legs may not receive the blood and oxygen they need. This lack of oxygen is called ischemia and it can cause pain. In severe cases, sores or gangrene can develop, which can result in you losing a limb. However, these symptoms are uncommon.

What are the symptoms?

Early in the disease, you may feel pain, cramping, or fatigue in your lower body when you walk or exercise. The pain with walking usually occurs in your buttocks, thighs, and legs. This symptom is called intermittent claudication because it stops when you rest. As the disease worsens, you may find that pain occurs when you walk for shorter distances. Ultimately, you may feel pain, usually in your toes or feet, even when you are resting.

Some men who have aortoiliac occlusive disease also experience erectile dysfunction, the inability to have or maintain an erection.

Aortoiliac disease may worsen if it is not treated. Signs that it has advanced include:

•	Severe pain, coldness, and numbness in a limb
•	Sores on your toes, heels, or lower legs
•	Dry, scaly, cracked skin on your foot. Major cracks, or fissures, may become infected if left untreated
•	Weakened muscles in your legs
•	Gangrene (tissue death), which may require amputation

If you experience any of these advanced symptoms, it usually means that your leg arteries are blocked in more than one place. Your physician may need to treat more than one site to prevent gangrene or limb loss.

 

What causes aortoiliac occlusive disease?

Atherosclerosis, or hardening of the arteries, causes most cases of aortoiliac occlusive disease.

Risk factors for hardening of the arteries include:

•	Smoking
•	High cholesterol
•	High blood pressure
•	Obesity
•	Having a family history of heart disease

In rare cases, a condition known as Takayasu’s arteritis may cause blockages in your aorta and its branches. Takayasu’s arteritis usually affects young Asian women between the ages of 10 and 30.

 

What tests will I need?

First your physician asks you questions about your general health, medical history, and symptoms. In addition, your physician conducts a physical exam. Together these are known as a patient history and exam. As part of your history and exam, your physician will ask you if you smoke or have high blood pressure. Your physician will also want to know when your symptoms occur and how often. A pulse examination that checks your pulse in several places in your legs for weak or absent pulses is part of your physical exam. For this test, your physician will simply place his or her fingers over pulse points.

After the history and exam, if your physician suspects you may have aortoiliac disease, he or she will perform tests, such as:

•	Ankle-brachial index (ABI): For the ABI, your physician measures your blood pressure in your ankle and in your arm. Your physician will compare the two numbers to determine your ABI. Normally, the blood pressures in your ankle and arm should be about equal. But if your ankle pressure is half your arm pressure (or lower), your leg arteries are probably narrowed. To perform the ABI, your physician will use an ordinary blood pressure cuff and an ultrasound device. The ABI helps your physician diagnose aortoiliac disease, but it does not identify which arteries are blocked.
•	Doppler ultrasound: Doppler ultrasound uses high-frequency sound waves that bounce off of blood cells and blood vessels to show blood flow and problems with the structure of blood vessels. This test identifies specific arteries that are blocked.
•	Angiography: In this test, your physician injects a contrast dye into your arteries and then takes x rays. The structure of your arteries appears on the x ray because x rays cannot pass through the dye. This test finds the exact location and pattern of blockages.

 

How is aortoiliac occlusive disease treated?

Lifestyle changes

In mild to moderate cases, your physician may recommend that you change certain aspects of your lifestyle. If you are a smoker, the most important step you can take is to quit smoking. Chemicals in tobacco can damage your arteries. These chemicals can also increase your chance of having complications from aortoiliac occlusive disease.

In addition to quitting smoking, your physician may recommend that you maintain a healthy weight, follow astructured walking program at least 3 or 4 times a week, and eat a low-fat and high-fiber diet. These changes help slow hardening of the arteries.

If you have diabetes, you need to control your blood sugar levels. If necessary, your physician may prescribemedications to lower high cholesterol and high blood pressure.

If you have diabetes, your physician may recommend that you receive foot care from a qualified healthcare professional and learn the basics of caring for your feet at home. This includes practicing foot hygiene, wearing protective, well fitting, and cushioned footwear, and avoiding injuries to your foot. This type of care can be very important because you can lose feeling in your feet and develop sores on them.

Medications

If you do not have a disqualifying medical condition, your physician may also prescribe pentoxifyline, which can improve the distance you are able to walk without pain. Other drugs your physician may prescribe include aspirin or clopidogrel (Plavix), either of which can lower your chances of blood clots.

Angioplasty or Surgery

If you have severe aortoiliac occlusive disease, particularly if it does not improve with the measures described above, your physician may recommend surgery or a minimally invasive treatment called angioplasty to improve the circulation in your legs. The choice of the treatment depends upon the pattern and extent of the blockages.

In an angioplasty, a long, thin, flexible tube called a catheter is inserted into a small puncture over an artery in your leg and is guided through your arteries to the blocked area. Once there, a special balloon attached to the catheter is inflated and deflated several times. The balloon pushes the plaque in your artery against your artery walls, widening the vessel. A tiny mesh-metal tube called a stent may then be placed into the narrowed area of your artery to keep it open. The stent remains permanently in your artery. After successful angioplasty, blood flows more freely through your artery.

Bypass surgery creates a detour around the narrowed or blocked sections of your artery. A Y-shaped tube made of synthetic fabric, called a graft, is attached to your aorta above the blockage. The two branches of the graft are then attached to either your left and right iliac arteries or other major arteries in each leg (called the femoral arteries). Bypass surgery restores blood flow in about 85 percent of patients. Results are commonly maintained for 10 or more years.

An endarterectomy is a way for your surgeon to remove the plaque from your artery. To perform an endarterectomy, your vascular surgeon makes an incision in your leg and removes the plaque contained in the inner lining of the diseased artery. This leaves a wide-open artery and restores blood flow through your leg artery.

Interventional Radiology

Interventional Radiology

Interventional radiology (IR) procedures are an advance in medicine that often replaces open surgical procedures. They are generally easier for the patient because they involve no large incisions, less risk, less pain and shorter recovery times. Advanced training of Interventional Radiologists with imaging guidance, can diagnose and treat a large number of ailments. Interventional radiologists perform a vast variety of procedures, the common ones include:   Diagnostic Therapeutic     Angiography (excluding Cardiac) Angioplasty and stent placement (excluding Cardiac) Needle Biopsy Artery Embolization Percutaneous Drainage Percutaneous Drainage   Foreign body extraction   Injection of clot lysing agents   Screening is useful in certain high-risk groups. This includes patients with Diabetes, High blood pressure, Smoking, High blood cholesterol, & with Family history of atherosclerotic problems and circulatory problems. Several simple screening tests, which are non-invasive and painless, can detect the problems early. These include: Carotid Scan Carotid Scan consists of a carotid duplex ultrasound scan and a blood pressure check for severe hypertension. It can detect the most frequent causes of stroke - significant internal carotid artery stenosis. Aortic Scan Aortic Scan an ultrasound scan of the aorta. The scan can tell how big the aneurysm is and when it needs treatment. PAD Scan PAD Scan is a doppler exam for PAD can quickly determine if there is any impairment in the circulation to the limbs. The exam can identify blockages in the leg arteries and tell how severe the blockage is and whether treatment is needed. Laboratory Tests Certain laboratory tests include Bleeding time (BT), Clotting Time (CT) & Prothrombin Time (PTT).   The highly specialized radiology department at Wockhardt hospitals is geared up to meet the clinician and patient needs in all spectrums of vascular disorders.

Diabetes and Foot Care

Diabetes and Foot Care

Peripheral Vascular Disease (PVD) in Diabetics affects infra-inguinal arteries more than the aorto-iliac system. Even though claudication is the commonest symptom of PVD, a diabetic is more likely to present with tissue loss without any previous symptoms Diabetic PVD is a more aggressive disease. Rapid progression of 'early' critical limb ischemia (CLI) to gangrene occurs in 40% of the diabetics as opposed to 9% in non diabetics. Sudden progression from intermittent claudication to limb threatening ischemia occurs in 35% of diabetics (19% in non-DM) with 21% risk of major amputation. A thorough evaluation of the diabetic foot is done at the center to decide on the modality of treatment. Management involves Total Contact Casting Regular debridement, with dressings Drugs to control infection Vascular reconstruction if required Elective surgeries to correct structural deformities At the center the Foot care specialist, Interventional Radiologist and Vascular surgeons work in unison, so as to perform foot sparing reconstructive procedures at the right time and thus prevent unnecessary amputation.

Endovenous Laser Treatment

Endovenous Laser Treatment

EVLT (Endovenous Laser Treatment) is a new viable alternative for treatment of varicose veins. Developed by leading phlebologists, it uses laser energy delivered in a thin fiber-optic probe to treat the underlying cause of the varicose veins. The laser energy damages vein walls, shrinking them and thus closing the faulty vein so that the blood can no longer flow through it. Performed under ultrasound guidance and local anesthesia, it allows a more gentle "minimally-invasive" approach to the treatment of varicose veins. Availability of EVLT at the centre provides the treatment of varicose veins as an outpatient procedure in about 45 minutes and then the patient can walk home.

Ischemia

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.

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Mechanism

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 results in tissue damage because of a lack of oxygen and nutrients. Ultimately, this causes great damage because of a buildup of metabolic wastes.

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 plaques 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
• Embolism (foreign bodies in the circulation, e.g. amniotic fluid embolism)
• Sickle cell disease (abnormally shaped hemoglobin)
• Induced g-forces which restrict the blood flow and force the blood to the extremities of the body, as in acrobatics and military flying

Consequences

Since oxygen is mainly bound to hemoglobin in red blood cells, insufficient blood supply causes tissue to become hypoxic, or, if no oxygen is supplied at all, anoxic. This can cause necrosis (i.e. cell death). In very aerobic tissues such as heart and brain, at body temperature necrosisdue to ischemia usually takes about 3-4 hours before becoming irreversible. This and typically some collateral circulation to the ischemic area accounts for the efficacy of "clot-buster" drugs such as Alteplase, given for stroke and heart attack within this time period. However, complete cessation of oxygenation of such organs for more than 20 minutes typically results in irreversible damage.

Ischemia is a feature of heart diseases, transient ischemic attacks, cerebrovascular accidents, ruptured arteriovenous malformations, andperipheral artery occlusive disease. The heart, the kidneys, and the brain are among the organs that are the most sensitive to inadequate blood supply. Ischemia in brain tissue, for example due to stroke or head injury, causes a process called the ischemic cascade to be unleashed, in which proteolytic enzymes, reactive oxygen species, and other harmful chemicals damage and may ultimately kill brain tissue.

Restoration of blood flow after a period of ischemia can actually be more damaging than the ischemia. Reintroduction of oxygen causes a greater production of damaging free radicals, resulting in reperfusion injury. With reperfusion injury, necrosis can be greatly accelerated.

Variations

The mechanism of ischemia depends on the type. One important type is cardiac ischemia, another is bowel ischemia.

Cardiac ischemia

Cardiac ischemia may cause chest pain, known as angina pectoris

Detection

Initial evaluation of chest-pain patients involves a 12 lead electrocardiogram (ECG) and cardiac markers such as troponins. These tests are highly specific but very insensitive and often leave the requirement for further testing to achieve an accurate diagnosis. Magnetocardiography(MCG) imaging utilises superconducting quantum interference devices (SQUIDs) to detect the weak magnetic fields generated by the heart's electrical fields. There is a direct correlation between abnormal cardiac depolarisation or repolarisation and abnormality in the magnetic field map. In July 2004, the Food and Drug Administration (FDA) approved the CardioMag Imaging MCG as a safe device for the non-invasive detection of ischemia.

Bowel ischemia

An ischemia in the large bowel caused by an inflammation results in ischemic colitis. An ischemia in the small bowel, on the other hand, caused by an inflammation results in mesenteric ischemia.

Cutaneous ischemia

Reduced blood flow to the skin layers may result in mottling or uneven, patchy discoloration of the skin.

Treatment

A dietary supplement based on superoxide dismutase and wheat gliadin (also known as glisodin) has shown promise in the protection against ischemia-reperfusion injury by inhibiting oxidative DNA damage.^{[citation needed]}

Aneurysm

An aneurysm (or aneurism) is a localized, blood-filled dilation (balloon-like bulge) of a blood vessel caused by disease or weakening of the vessel wall. Aneurysms most commonly occur in arteries at the base of the brain (the circle of Willis) and in theaorta (the main artery coming out of the heart, a so-called aortic aneurysm). As the size of an aneurysm increases, there is an increased risk of rupture, which can result in severe hemorrhage or other complications including sudden death.

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Diagnosis

Diagnosis of a ruptured cerebral aneurysm is commonly made by finding signs of subarachnoid hemorrhage on a CT scan (Computerized Tomography, sometimes called a CAT scan). The CT scan is a computerized test that rapidly X-rays the body in cross-sections, or slices, as the body is moved through a large, circular machine. If the CT scan is negative but a ruptured aneurysm is still suspected, a lumbar puncture is performed to detect blood in the cerebrospinal fluid (CSF) tCTA) is an alternative to the traditional method and can be performed without the need for arterial catheterization. This test combines a regular CT scan with a contrast dye injected into a vein. Once the dye is injected into a vein, it travels to the brain arteries, and images are created using a CT scan. These images show exactly how blood flows into the brain arteries.

Structure

In a true aneurysm the inner layers of a vessel have bulged outside the outer layer that normally confines them. The aneurysm is surrounded by these inner layers.

A false- or pseudoaneurysm does not primarily involve such distortion of the vessel. It is a collection of blood leaking completely out of an artery or vein, but confined next to the vessel by the surrounding tissue. This blood-filled cavity will eventually either thrombose (clot) enough to seal the leak or it will rupture out of the tougher tissue enclosing it and flow freely between layers of other tissues or into looser tissues. Pseudoaneurysms can be caused by trauma that punctures the artery and are a known complication of percutaneous arterial procedures such as arteriography or of arterial grafting or of use of an artery for injection, such as by drug abusers unable to find a usable vein. Like true aneurysms they may be felt as an abnormal pulsatile mass on palpation.

Location

Most non-intracranial aneurysms (94%) arise distal to the origin of the renal arteries at the infrarenal abdominal aorta, a condition mostly caused by atherosclerosis. The thoracic aorta can also be involved. One common form of thoracic aortic aneurysm involves widening of the proximal aorta and the aortic root, which leads toaortic insufficiency. Aneurysms occur in the legs also, particularly in the deep vessels (e.g., the popliteal vessels in the knee). Arterial aneurysms are much more common, but venous aneurysms do happen (for example, the popliteal venous aneurysm).

• While most aneurysms occur in an isolated form, the occurrence of berry aneurysms of the anterior communicating artery of the circle of Willis is associated with autosomal dominant polycystic kidney disease (ADPKD).
• The third stage of syphilis also manifests as aneurysm of the aorta, which is due to loss of the vasa vasorum in the tunica adventitia.

Risks

Rupture and blood clotting are the risks involved with aneurysms. Rupture leads to drop in blood pressure, rapid heart rate, and lightheadedness. The risk of death is high except for rupture in the extremities.

Blood clots from popliteal arterial aneurysms can travel downstream and suffocate tissue. Only if the resulting pain and/or numbness are ignored over a significant period of time will such extreme results as amputation be needed. As long as treatment is sought quickly, a doctor should be able to provide non-invasive treatment. Aneurysms should be treated with care as over pressure when trying to get rid of them can cause them to shift. Clotting in popliteal venous aneurysms are much more serious as the clot can embolise and travel to the heart, or through the heart to the lungs (a pulmonary embolism). Risk factors for an aneurysm are diabetes,obesity, hypertension, tobacco use, alcoholism, and copper deficiency.

A minority of aneurysms are caused by a copper deficiency. Numerous animal experiments have shown that a copper deficiency can cause diseases affected byelastin tissue strength [Harris]. The lysyl oxidase that cross links connective tissue is secreted normally, but its activity is reduced, due, no doubt, to some of the initial enzyme molecules (apo-enzyme or enzyme without the copper) failing to contain copper.

Aneurysms of the aorta are the chief cause of death of copper deficient chickens, and also depleting copper produces aneurysms in turkeys.

Men who die of aneurysms have a liver content which can be as little as 26% of normal. The median layer of the blood vessel (where the elastin is) is thinner but its elastin copper content is the same as normal men. The overall thickness is not different. The body must therefore have some way of preventing elastin tissue from growing if there is not enough activated lysyl oxidase for it. Men are more susceptible to aneurysms than young women, probably because estrogen increases the efficiency of absorption of copper. However, women can be affected by some of these problems after pregnancy, probably because women must give the liver of their babies large copper stores in order for them to survive the low levels of copper in milk. A baby’s liver has up to ten times as much copper as adult livers. Elastin is about as flexible as a rubber band and can stretch to two times its length. Collagen is about 1000 times stiffer.

A healthy artery can resist blood pressure of up to about 1,000 mm Hg before rupturing. Therefore keeping strength of arteries up would seem to be even more important than keeping blood pressure down.

Formation

Most frequent site of occurrence is in the anterior cerebral artery from the circle of Willis. The occurrence and expansion of an aneurysm in a given segment of the arterial tree involves local hemodynamic factors and factors intrinsic to the arterial segment itself.

The human aorta is a relatively low-resistance circuit for circulating blood. The lower extremities have higher arterial resistance, and the repeated trauma of a reflected arterial wave on the distal aorta may injure a weakened aortic wall and contribute to aneurysmal degeneration. Systemic hypertension compounds the injury, accelerates the expansion of known aneurysms, and may contribute to their formation.

Aneurysm formation is probably the result of multiple factors affecting that arterial segment and its local environment.

Hemodynamically, the coupling of aneurysmal dilation and increased wall stress is approximated by the law of Laplace. Specifically, the Laplace law states that the (arterial) wall tension is proportional to the pressure times the radius of the arterial conduit (T = P X R). As diameter increases, wall tension increases, which contributes to increasing diameter. As tension increases, risk of rupture increases. Increased pressure (systemic hypertension) and increased aneurysm size aggravate wall tension and therefore increase the risk of rupture. In addition, the vessel wall is supplied by the blood within its lumen in humans. Therefore in a developing aneurysm, the most ischemic portion of the aneurysm is at the farthest end, resulting in weakening of the vessel wall there and aiding further expansion of the aneurysm. Thus eventually all aneurysms will, if left to complete their evolution, rupture without intervention. In dogs, collateral vessels supply the vessel and aneurysms are rare.

Treatment

Historically, the treatment of arterial aneurysms has been surgical intervention, or watchful waiting in combination with control of blood pressure. Recently,endovascular or minimally invasive techniques have been developed for many types of aneurysms.

Treatment of aneurysms

Currently there are two treatment options for brain aneurysms: surgical clipping or endovascular coiling. Surgical clipping was introduced by Walter Dandy of theJohns Hopkins Hospital in 1937. It consists of performing a craniotomy, exposing the aneurysm, and closing the base of the aneurysm with a clip. The surgical technique has been modified and improved over the years. Surgical clipping remains the best method to permanently eliminate aneurysms. Endovascular coiling was introduced by Guido Guglielmi at UCLA in 1991. It consists of passing a catheter into the femoral artery in the groin, through the aorta, into the brain arteries, and finally into the aneurysm itself. Once the catheter is in the aneurysm, platinum coils are pushed into the aneurysm and released. These coils initiate a clotting or thrombotic reaction within the aneurysm that, if successful, will eliminate the aneurysm. In the case of broad-based aneurysms, a stent is passed first into the parent artery to serve as a scaffold for the coils ("stent-assisted coiling").

At this point it appears that the risks associated with surgical clipping and endovascular coiling, in terms of stroke or death from the procedure, are the same. The major problem associated with endovascular coiling, however, is the high recurrence rate and subsequent bleeding of the aneurysms. For instance, the most recent study by Jacques Moret and colleagues from Paris, France, (a group with one of the largest experiences in endovascular coiling) indicates that 28.6% of aneurysms recurred within one year of coiling, and that the recurrence rate increased with time. (Piotin M et al., Radiology 243(2):500-508, May 2007) These results are similar to those previously reported by other endovascular groups. For instance Jean Raymond and colleagues from Montreal, Canada, (another group with a large experience in endovascular coiling) reported that 33.6% of aneurysms recurred within one year of coiling. (Raymond J et al., Stroke 34(6):1398-1403, June 2003) The long-term coiling results of one of the two prospective, randomized studies comparing surgical clipping versus endovascular coiling, namely the International Subarachnoid Aneurysm Trial (ISAT) are turning out to be similarly worrisome. In ISAT, the need for late retreatment of aneurysms was 6.9 times more likely for endovascular coiling as compared to surgical clipping. (Campi A et al., Stroke 38(5):1538-1544, May 2007)

Therefore it appears that although endovascular coiling is associated with a shorter recovery period as compared to surgical clipping, it is also associated with a significantly higher recurrence and bleeding rate after treatment. Patients who undergo endovascular coiling need to have annual studies (such as MRI/MRA, CTA, or angiography) indefinitely to detect early recurrences. If a recurrence is identified, the aneurysm needs to be retreated with either surgery or further coiling. The risks associated with surgical clipping of previously-coiled aneurysms are very high. Ultimately, the decision to treat with surgical clipping versus endovascular coiling should be made by a cerebrovascular team with extensive experience in both modalities. At present it appears that only older patients with aneurysms that are difficult to reach surgically are more likely to benefit from endovascular coiling. These generalizations, however, are difficult to apply to every case, which is reflected in the wide variability internationally in the use of surgical clipping versus endovascular coiling.

Treatment of aortic and peripheral aneurysms

For aortic aneurysms or aneurysms that happen in the vessels that supply blood to the arms, legs, and head (the peripheral vessels), surgery involves replacing the weakened section of the vessel with an artificial tube, called a graft that is sutured at vascular stumps. Instead of sewing, the graft 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 Less invasive endovascular techniques allow covered metallic stent grafts to be inserted through the arteries of the leg and deployed across the aneurysm.