Arterial embolism is a sudden interruption of blood flow to an organ or body part due to an embolus adhering to the wall of an artery blocking the flow of blood, the major type of embolus being a blood clot ( thromboembolism). Sometimes, pulmonary embolism is classified as arterial embolism as well,MedlinePlus > Arterial embolism
Sean O. Stitham, MD and David C. Dugdale III, MD. Also reviewed by David Zieve, MD. Reviewed last on: August 5, 2008. Alternative link

in the sense that the clot follows the pulmonary artery carrying deoxygenated blood away from the heart. However, pulmonary embolism is generally classified as a form of venous embolism, because the embolus forms in veins. Arterial embolism is the major cause of

infarction Infarction is tissue death (necrosis) due to Ischemia, inadequate blood supply to the affected area. It may be caused by Thrombosis, artery blockages, rupture, mechanical compression, or vasoconstriction. The resulting lesion is referred to as a ...

(which may also be caused by e.g. arterial compression, rupture or pathological vasoconstriction).

Signs and symptoms

Symptoms may begin quickly or slowly depending on the size of the embolus and how much it blocks the blood flow. Symptoms of embolisation in an organ vary with the organ involved but commonly include: * Pain in the involved body part * Temporarily decreased organ function Later symptoms are closely related to

of the affected tissue. This may cause permanently decreased organ function. For example, symptoms of

myocardial infarction A myocardial infarction (MI), commonly known as a heart attack, occurs when Ischemia, blood flow decreases or stops in one of the coronary arteries of the heart, causing infarction (tissue death) to the heart muscle. The most common symptom ...

mainly include chest pain, dyspnea, diaphoresis (an excessive form of sweating), weakness, light-headedness, nausea, vomiting, and palpitations. Symptoms of limb infarction include coldness, decreased or no pulse beyond the site of blockage, pain, muscle spasm, numbness and tingling, pallor and muscle weakness, possibly to the grade of paralysis in the affected limb.

Commonly occluded sites

Arterial emboli often occur in the legs and feet. Some may occur in the brain, causing a stroke, or in the heart, causing a heart attack. Less common sites include the kidneys, intestines, and eyes.

Risk factors

Risk factors for thromboembolism, the major cause of arterial embolism, include disturbed blood flow (such as in atrial fibrillation and mitral stenosis), injury or damage to an artery wall, and hypercoagulability (such as increased platelet count). Mitral stenosis poses a high risk of forming emboli which may travel to the brain and cause

stroke Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...

. Endocarditis increases the risk for thromboembolism, by a mixture of the factors above.

Atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis, characterized by development of abnormalities called lesions in walls of arteries. This is a chronic inflammatory disease involving many different cell types and is driven by eleva ...

in the aorta and other large blood vessels is a common risk factor, both for thromboembolism and cholesterol embolism. The legs and feet are major impact sites for these types. Thus, risk factors for atherosclerosis are risk factors for arterial embolisation as well: * advanced age * cigarette smoking *

hypertension Hypertension, also known as high blood pressure, is a Chronic condition, long-term Disease, medical condition in which the blood pressure in the artery, arteries is persistently elevated. High blood pressure usually does not cause symptoms i ...

(high blood pressure) *

obesity Obesity is a medical condition, considered by multiple organizations to be a disease, in which excess Adipose tissue, body fat has accumulated to such an extent that it can potentially have negative effects on health. People are classifi ...

hyperlipidemia Hyperlipidemia is abnormally high levels of any or all lipids (e.g. fats, triglycerides, cholesterol, phospholipids) or lipoproteins in the blood. citing: and The term ''hyperlipidemia'' refers to the laboratory finding itself and is also use ...

, e.g. hypercholesterolemia, hypertriglyceridemia, elevated lipoprotein (a) or apolipoprotein B, or decreased levels of HDL cholesterol) *

diabetes mellitus Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained hyperglycemia, high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or th ...

* Sedentary lifestyle * stress Other important risk factors for arterial embolism include: * recent surgery (both for thromboembolism and air embolism) * previous stroke or cardiovascular disease * a history of long-term intravenous therapy (for air embolism) *

Bone fracture A bone fracture (abbreviated FRX or Fx, Fx, or #) is a medical condition in which there is a partial or complete break in the continuity of any bone in the body. In more severe cases, the bone may be broken into several fragments, known as a ''c ...

(for fat embolism) A septal defect of the heart makes it possible for paradoxical embolization, which happens when a clot in a vein enters the right side of the heart and passes through a hole into the left side. The clot can then move to an artery and cause arterial embolisation.

Pathophysiology

An arterial embolism is caused by one or more emboli getting stuck in an artery and blocking blood flow, causing ischemia, possibly resulting in

with tissue death ( necrosis). Individuals with arterial thrombosis or embolism often develop collateral circulation to compensate for the loss of arterial flow. However, it takes time for sufficient collateral circulation to develop, making affected areas more vulnerable for sudden occlusion by embolisation than for e.g. gradual occlusion as in

atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis, characterized by development of abnormalities called lesions in walls of arteries. This is a chronic inflammatory disease involving many different cell types and is driven by eleva ...

.Chapter 4 in: 8th edition.

Materials

Arterial embolisms can consist of various materials, including: * Thromboembolism – embolism of thrombus or blood clot.MDGuidelines > Arterial Embolism And Thrombosis
From ''The Medical Disability Advisor'' by Presley Reed, MD. Retrieved on April 30, 2010 * Cholesterol embolism - embolism of cholesterol, often from atherosclerotic plaque inside a vessel. * Fat embolism – embolism of bone fracture or fat droplets. * Air embolism (also known as a gas embolism) – embolism of air bubbles. * Septic embolism – embolism of pus containing bacteria. * ''Cancer embolism'' In contrast, amniotic fluid embolism almost exclusively affects the venous side.

Diagnosis

In addition to evaluating the symptoms above, the health care provider may find decreased or no

blood pressure Blood pressure (BP) is the pressure of Circulatory system, circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term ...

in the arm or leg. Tests to determine any underlying cause for thrombosis or embolism and to confirm presence of the obstruction may include: * Doppler ultrasound, especially

duplex ultrasonography Doppler ultrasonography is medical ultrasonography that employs the Doppler effect to perform medical imaging, imaging of the movement of tissue (biology), tissues and body fluids (usually blood), and their relative velocity to the ultrasound pro ...

. It may also involve transcranial doppler exam of arteries to the brain *

Echocardiography Echocardiography, also known as cardiac ultrasound, is the use of ultrasound to examine the heart. It is a type of medical imaging, using standard ultrasound or Doppler ultrasound. The visual image formed using this technique is called an ec ...

, sometimes involving more specialized techniques such as Transesophageal echocardiography (TEE) or myocardial contrast echocardiography (MCE) to diagnose

Arteriography Angiography or arteriography is a medical imaging technique used to visualize the inside, or lumen (anatomy), lumen, of blood vessels and organs of the body, with particular interest in the artery, arteries, veins, and the Heart#Chambers, heart ...

of the affected extremity or organ Digital subtraction angiography is useful in individuals where administration of radiopaque contrast material must be kept to a minimum. *

Magnetic resonance imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and ...

(MRI) * Blood tests for measuring elevated enzymes in the blood, including cardiac-specific troponin T and/or troponin I, myoglobins, and creatine kinase isoenzymes. These indicate embolisation to the heart that has caused

. Myoglobins and creatine kinase are also elevated in the blood in embolisation in other locations. * Blood cultures may be done to identify the organism responsible for any causative infection *

Electrocardiography Electrocardiography is the process of producing an electrocardiogram (ECG or EKG), a recording of the heart's electrical activity through repeated cardiac cycles. It is an electrogram of the heart which is a graph of voltage versus time of t ...

(ECG) for detecting

Angioscopy Angioscopy is a medical technique for visualizing the interior of blood vessels. In this technique, a flexible fibre bundle endoscope An endoscope is an inspection instrument composed of image sensor, optical lens, light source and mechanical d ...

using a flexible fiberoptic catheter inserted directly into an artery.

Prevention

Prevention of

, which is a major risk factor of arterial embolism, can be performed e.g. by

dieting Dieting is the practice of eating food in a regulated way to decrease, maintain, or increase body weight, or to prevent and treat diseases such as diabetes and obesity. As weight loss depends on calorie intake, List of diets, different kinds of ...

physical exercise Exercise or workout is physical activity that enhances or maintains fitness and overall health. It is performed for various reasons, including weight loss or maintenance, to aid growth and improve strength, develop muscles and the cardio ...

and smoking cessation. In case of high risk for developing thromboembolism, antithrombotic medication such as warfarin or coumadin may be taken prophylactically. Antiplatelet drugs may also be needed.

Treatment

Treatment is aimed at controlling symptoms and improving the interrupted blood flow to the affected area of the body. Medications include: * Antithrombotic medication. These are commonly given because thromboembolism is the major cause of arterial embolism. Examples are: ** Anticoagulants (such as warfarin or heparin) and antiplatelet medication (such as aspirin, ticlopidine, and clopidogrel) can prevent new clots from forming ** Thrombolytics (such as streptokinase) can dissolve clots * Painkillers given

intravenous Intravenous therapy (abbreviated as IV therapy) is a medical technique that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutr ...

ly * Vasodilators to relax and dilate blood vessels. Appropriate drug treatments successfully produce thrombolysis and removal of the clot in 50% to 80% of all cases. Antithrombotic agents may be administered directly onto the clot in the vessel using a flexible catheter (''intra-arterial thrombolysis''). Intra-arterial thrombolysis reduces thromboembolic occlusion by 95% in 50% of cases, and restores adequate blood flow in 50% to 80% of cases. Surgical procedures include: * Arterial bypass surgery to create another source of blood supply * Embolectomy, to remove the embolus, with various techniques available: ** Thromboaspiration ** Angioplasty with balloon catheterization with or without implanting a stent Balloon catheterization or open embolectomy surgery reduces mortality by nearly 50% and the need for limb amputation by approximately 35%. ** Embolectomy by open surgery on the artery If extensive necrosis and gangrene has set in an arm or leg, the limb may have to be amputated. Limb amputation is in itself usually remarkably well-tolerated, but is associated with substantial mortality (~50%), primarily because of the severity of the diseases in patients where it is indicated.

Prognosis

How well a patient does depends on the location of the clot and to what extent the clot has blocked blood flow. Arterial embolism can be serious if not treated promptly. Without treatment, it has a 25% to 30%

mortality rate Mortality rate, or death rate, is a measure of the number of deaths (in general, or due to a specific cause) in a particular Statistical population, population, scaled to the size of that population, per unit of time. Mortality rate is typically ...

. The affected area can be permanently damaged, and up to approximately 25% of cases require amputation of an affected extremity. Arterial emboli may recur even after successful treatment.

Complications

Possible complications of arterial embolism depend on the site of the obstruction: * In the heart it can cause

* In the brain, it can cause a transient ischemic attack (TIA), and, in prolonged blood obstruction,

. * Blockage of arteries that supply arms or legs may result in necrosis and

gangrene Gangrene is a type of tissue death caused by a lack of blood supply. Symptoms may include a change in skin color to red or black, numbness, swelling, pain, skin breakdown, and coolness. The feet and hands are most commonly affected. If the ga ...

* Temporary or permanent decrease or loss of other organ functions * In septic embolism, there can be infection of the affected tissue or even septic shock, potentially leading to

and

sepsis Sepsis is a potentially life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage of sepsis is followed by suppression of the immune system. Common signs and s ...

Epidemiology

In the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, approximately 550,000 people die each year from heart-related arterial embolism and thrombosis. Approximately 250,000 of these individuals are female, and approximately 100,000 of all these deaths are considered premature, that is, prior to the age of average life expectancy.

References

External links

{{Medical resources , DiseasesDB = , ICD10 = {{ICD10, I, 74, , i, 74 , ICD9 = , ICDO = , OMIM = , MedlinePlus = 001102 , eMedicineSubj = , eMedicineTopic = , MeshID = Diseases of arteries, arterioles and capillaries