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Health See other Health Articles Title: Systemic Embolism in Atrial Fibrillation: Less Common Than Stroke but as Fatal MINNEAPOLIS, MN — A new review based on data from four large contemporary trials of patients with atrial fibrillation (AF) has shed light on the incidence, risk factors, and morbidity of extracranial systemic embolic events (SEEs)—a less common but often lethal outcome[1]. In this analysis of more than 30,000 patients, nine in 10 thromboembolic events were stroke and only one in 10 were systemic embolic events. Within 30 days of an extracranial systemic embolic event, 25% of the patients had died (the same mortality rate as stroke) and only 54% of patients had fully recovered. Thus, "clearly, these events are not benign and the adverse outcomes we observed suggest that SEEs should be managed as aggressively as stroke," Dr Wobo Bekwelem (University of Minnesota Medical School, Twin Cities) and colleagues report in their study, published July 29, 2015 in Circulation. The real value is that this study used four randomized well-powered trials and provides the largest description of SEE to date, Dr Steven A Lubitz (Harvard Medical School, Boston, MA), coauthor with Dr Neal A Chatterjee (Harvard Medical School) of an accompanying editorial[2], told heartwire from Medscape. The findings suggest that physicians should advise patients that "antithrombotic treatment of [AF] is key to their well-being and survival, due to the danger associated with all embolic events, whether to the brain or periphery," senior author Dr Alan T Hirsch (University of Minnesota Medical School) commented. When it comes to good cardiovascular health, "there is nothing 'peripheral' about peripheral ischemic events," he said. How Does SEE Differ From Stroke? Patients with AF are at risk of thromboembolic events, but relatively little is known about their risk of systemic embolism as opposed to stroke. "We think that both stroke and systemic embolism have the same underlying mechanism, at least in AF—which is that a clot comes from the left atrium and goes to the brain or [another organ]," coauthor Dr Stuart J Connolly (McMaster University, Hamilton, ON) commented. Moreover, the brain only gets about 25% of the body's blood supply, but 90% to 95% of the emboli travel to the brain, "which has always been a bit of a mystery," he said. To investigate this, Bekwelem and colleagues readjudicated all suspected cases of systemic embolic events reported among 37,973 participants of four large, randomized, contemporary trials of anticoagulation in AF: the Atrial Fibrillation Clopidogrel Trial with Irbesartan for Prevention of Vascular Events trials (ACTIVE-A and ACTIVE-W), the Apixaban Versus Acetylsalicylic Acid [ASA] to Prevent Stroke in Atrial Fibrillation in Patients Who Have Failed or Are Unsuitable for Vitamin K Antagonist Treatment Study (AVERROES), and the Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) trial. During a mean follow-up of 2.4 years, 1677 patients had a stroke, 174 patients had a confirmed clinical and objective evidence of sudden loss of perfusion of a limb or an organ (SEE), and 45 patients had both types of event. The incidence of SEE was 0.24/100 patient years (roughly 0.2% per year), whereas the incidence of stroke was 1.92/100 patient-years (roughly 1.9% per year). Patients with both types of events had a similar mean age (73.5) and CHADS2 score (2.5). However, compared with patients with stroke, those with a SEE were more likely to be female (56% vs 47%, P=0.01), white (77% vs 67.5%, P=0.01), and current or past smokers (54% vs 44%, P=0.01), with current or past peripheral artery disease (PAD) (9% vs 5%, P=0.02) and previous MI (26.5% vs 17.6%, P=0.005) or SEE (20% vs 3%, P=0.0001). The systemic embolism occurred more frequently in patients' legs (58%) and less often in their visceral-mesenteric organs (32%) or arms (10%). Most patients with an extracranial SEE were hospitalized and had a surgical or endovascular procedure (60%); about a third were hospitalized only (31%); 5% received outpatient care; and 4% had an amputation. The 30-day mortality rate was similar for patients with systemic embolism alone (24%) or stroke alone (25%). However, compared with patients with stroke, the 30-day mortality was higher for patients with a mesenteric embolism (55%) and lower for patients with an embolism in the legs or arms (17% and 9%, respectively). Within 30 days, only 54% of patients with SEE had fully recovered and 20% survived with deficits. The relative risk of death during follow-up was 4.33 (95% CI 3.29–5.70) after a SEE vs 6.79 (95% CI 6.22–7.41) after a stroke. Fragile Patients, Study Will Help Guide Future Research According to Hirsch, the study's key message is: "Take each potential ischemic event with comparable seriousness. . . . These are fragile patients, and end-organ ischemia that causes recognizable dysfunction is a very poor prognostic signal." The diagnosis can be tricky. "If there's a sudden loss of blood supply to a limb in a patient with AF, most clinicians will make a diagnosis [of SEE] fairly quickly and confirm it by doing . . . an angiogram, where you can see the blocked arteries easily," Connolly said. However, an embolism that travels to the small bowel can mimic other intestinal diseases, or an embolism that travels to the kidney might also be difficult to diagnose. This study was not designed to describe what treatments are useful to prevent SEE, but for stroke, anticoagulants work the best, and antiplatelet therapies work to a lesser extent, and this appears to be the same for extracranial SEE, he continued. "Given that several SEE risk factors (eg, female gender, peripheral vascular disease, prior myocardial infarction) are included in stroke-prediction algorithms, it is unlikely that the report by Bekwelem et al will significantly modify the decision to initiate anticoagulation," Lubitz and Chatterjee write. However, "these data help us 'SEE' embolic risk more clearly, [and] ultimately such clarity will guide more effective application of therapies to stem the rising tide of AF and thromboembolic morbidity," they conclude. The authors and editorialists have no relevant financial relationships. Related Links Silent Atrial Fibrillation Increases Stroke Risk ASSERT: Silent atrial fibrillation increases stroke risk ASSERT: Device-Detected Atrial Tachyarrhythmias Are Common, Raise Stroke Risk Poster Comment: embolism Also found in: Dictionary/thesaurus, Financial, Encyclopedia, Wikipedia. Embolism Definition An embolism is an obstruction in a blood vessel due to a blood clot or other foreign matter that gets stuck while traveling through the bloodstream. The plural of embolism is emboli. Description Emboli have moved from the place where they were formed through the bloodstream to another part of the body, where they obstruct an artery and block the flow of blood. The emboli are usually formed from blood clots but are occasionally comprised of air, fat, or tumor tissue. Embolic events can be multiple and small, or single and massive. They can be life-threatening and require immediate emergency medical care. There are three general categories of emboli: arterial, gas, and pulmonary. Pulmonary emboli are the most common. Arterial embolism In arterial emboli, blood flow is blocked at the junction of major arteries, most often at the groin, knee, or thigh. Arterial emboli are generally a complication of heart disease. An arterial embolism in the brain (cerebral embolism) causes stroke, which can be fatal. An estimated 5-14% of all strokes are caused by cerebral emboli. Arterial emboli to the extremities can lead to tissue death and amputation of the affected limb if not treated effectively within hours. Intestines and kidneys can also suffer damage from emboli. Gas embolism Gas emboli result from the compression of respiratory gases into the blood and other tissues due to rapid changes in environmental pressure, for example, while flying or scuba diving. As external pressure decreases, gases (like nitrogen) that are dissolved in the blood and other tissues become small bubbles that can block blood flow and cause organ damage. Pulmonary embolism In a pulmonary embolism, a common illness, blood flow is blocked at a pulmonary artery. When emboli block the main pulmonary artery, and in cases where there are no initial symptoms, a pulmonary embolism can quickly become fatal. According to the American Heart Association, an estimated 600,000 Americans develop pulmonary emboli annually and 60,000 die from it. A pulmonary embolism is difficult to diagnose. Less than 10% of patients who die from a pulmonary embolism were diagnosed with the condition. More than 90% of cases of pulmonary emboli are complications of deep vein thrombosis, blood clots in the deep vein of the leg or pelvis. Causes and symptoms Arterial emboli are usually a complication of heart disease where blood clots form in the heart's chambers. Gas emboli are caused by rapid changes in environmental pressure that could happen when flying or scuba diving. A pulmonary embolism is caused by blood clots that travel through the blood stream to the lungs and block a pulmonary artery. More than 90% of the cases of pulmonary embolism are a complication of deep vein thrombosis, which typically occurs in patients who have had orthopedic surgery and patients with cancer or other chronic illnesses like congestive heart failure. Risk factors for arterial and pulmonary emboli include: prolonged bed rest, surgery, childbirth, heart attack, stroke, congestive heart failure, cancer, obesity, a broken hip or leg, oral contraceptives, sickle cell anemia, chest trauma, certain congenital heart defects, and old age. Risk factors for gas emboli include: scuba diving, amateur plane flight, exercise, injury, obesity, dehydration, excessive alcohol, colds, and medications such as narcotics and antihistamines. Symptoms of an arterial embolism include: severe pain in the area of the embolism pale, bluish cool skin numbness tingling muscular weakness or paralysis Common symptoms of a pulmonary embolism include: labored breathing, sometimes accompanied by chest pain a rapid pulse a cough that may produce sputum a low-grade fever fluid build-up in the lungs Less common symptoms include: coughing up blood pain caused by movement or breathing leg swelling bluish skin fainting swollen neck veins Diagnosis An embolism can be diagnosed through the patient's history, a physical exam, and diagnostic tests. The use of various tests may change, as physicians and clinical guidelines evaluate the most effective test in terms of accuracy and cost. For arterial emboli, cardiac ultrasound and/or arteriography are ordered. For a pulmonary embolism, a chest x ray, lung scan, pulmonary angiography, electrocardiography, arterial blood gas measurements, and venography or venous ultrasound could be ordered. Diagnosing an arterial embolism Ultrasound uses sound waves to create an image of the heart, organs, or arteries. The technologist applies gel to a hand-held transducer, then presses it against the patient's body. The sound waves are converted into an image that can be displayed on a monitor. Performed in an outpatient diagnostic laboratory, the test takes 30-60 minutes. An arteriogram is an x ray in which a contrast medium is injected to make the arteries visible. It can be performed in a radiology unit, outpatient clinic, or diagnostic center of a hospital. Diagnosing a pulmonary embolism A chest x ray can show fluid build-up and detect other respiratory diseases. The perfusion lung scan shows poor flow of blood in areas beyond blocked arteries. The patient inhales a small amount of radiopharmaceutical and pictures of airflow into the lungs are taken with a gamma camera. Then a different radiopharmaceutical is injected into an arm vein and lung blood flow is scanned. A normal result essentially rules out a pulmonary embolism. A lung scan can be performed in a hospital or an outpatient facility and takes about 45 minutes. Pulmonary angiography is one of the most reliable tests for diagnosing a pulmonary embolism. Pulmonary angiography is a radiographic test that involves injection of a radio contrast agent to show the pulmonary arteries. A cinematic camera records the blood flow through the patient, who lies on a table. Pulmonary angiography is usually performed in a hospital's radiology department and takes 30-60 minutes. An electrocardiograph shows the heart's electrical activity and helps distinguish a pulmonary embolism from a heart attack. Electrodes covered with conducting jelly are placed on the patient's chest, arms, and legs. Impulses of the heart's activity are traced on paper. The test takes about 10 minutes. Arterial blood gas measurements are sometimes helpful but, alone, they are not diagnostic for pulmonary embolism. Blood is taken from an artery instead of a vein, usually in the wrist. Venography is used to look for the most likely source of a pulmonary embolism, deep vein thrombosis. It is very accurate, but it is not used often, because it is painful, expensive, exposes the patient to a fairly high dose of radiation, and can cause complications. Venography identifies the location, extent, and degree of attachment of the blood clots and enables the condition of the deep leg veins to be assessed. A contrast solution is injected into a foot vein through a catheter. The physician observes the movement of the solution through the vein with a fluoroscope while a series of x rays are taken. Venography takes between 30-45 minutes and can be done in a physician's office, a laboratory, or a hospital. Radionuclide venography, in which a radioactive isotope is injected, is occasionally used, especially if a patient has had reactions to contrast solutions. Venous ultrasound is the preferred evaluation of leg veins. As noninvasive methods such as high-speed computed tomography (CT) scanning improve, they may be used to diagnose emboli. For instance, spiral (also called helical) CT scans may be the preferred tool for diagnosing pulmonary embolism in pregnant women. Treatment Patients with emboli require immediate hospitalization. They are generally treated with clot-dissolving and/or clot-preventing drugs. Thrombolytic therapy to dissolve blood clots is the definitive treatment for a severe pulmonary embolism. Streptokinase, urokinase, and recombinant tissue plasminogen activator (TPA) are used. Heparin has been the anticoagulant drug of choice for preventing formation of blood clots. A new drug has been approved for treatment of acute pulmonary emboli. Called fondaparinux (Arixtra), it usually is administered with Warfarin, an oral anticoagulant. Warfarin is sometimes used with other drugs to treat acute embolism events and is usually continued after the hospitalization to help prevent future emboli. Arixtra also has been used on an ongoing basis to prevent pulmonary emboli. In the case of an arterial embolism, the affected limb is placed in a dependent position and kept warm. Embolectomy is the treatment of choice in the majority of early cases of arterial emboli in the extremities. In this procedure, a balloon-tipped catheter is inserted into the artery to remove thromboembolic matter. With a pulmonary embolism, oxygen therapy is often used to maintain normal oxygen concentrations. For people who can't take anticoagulants and in some other cases, surgery may be needed to insert a device that filters blood returning to the heart and lungs. Prognosis Of patients hospitalized with an arterial embolism, 25-30% die, and 5-25% require amputation of a limb. About 10% of patients with a pulmonary embolism die suddenly within the first hour of onset of the condition. The outcome for all other patients is generally good; only 3% of patients die who are properly diagnosed early and treated. In cases of an undiagnosed pulmonary embolism, about 30% of patients die. Prevention Embolism can be prevented in high risk patients through antithrombotic drugs such as heparin, venous interruption, gradient elastic stockings, and intermittent pneumatic compression of the legs. The combination of graduated compression stockings and low-dose heparin is significantly more effective than low-dose heparin alone. Gradient elastic stockings, also called antiembolism stockings, decrease the risk of blood clots by compressing superficial leg veins and forcing blood into the deep veins. They can be knee-, thigh-, or waist-length. Many physicians order the use of stockings before surgery and until there is no longer an elevated risk of developing blood clots. The risk of deep vein thrombosis after surgery is reduced 50% with the use of these stockings. The American Heart Association recommends that the use of graduated compression stockings be considered for all high-risk surgical patients. Intermittent pneumatic compression involves wrapping knee- or thigh-high cuffs around the legs to prevent blood clots. The cuffs are connected to a pump that inflates and deflates, mimicking the heart's normal pumping action and reducing the pooling of blood. Intermittent pneumatic compression can be used during surgery and recovery and continues until there is no longer an elevated risk of developing blood clots. The American Heart Association recommends the use of intermittent pneumatic compression for patients who cannot take anticoagulants, for example, spinal cord and brain trauma patients. mesenteric [mes′enter′ik] Etymology: Gk, mesos, middle, enteron, intestine pertaining to the mesentery, the double layer of peritoneum suspending the intestine from the posterior abdominal wall. Post Comment Private Reply Ignore Thread Top • Page Up • Full Thread • Page Down • Bottom/Latest
#1. To: Tatarewicz (#0)
extracranial systemic embolic events -- that was the name of my high school rock band!
They were a bunch of clots?
Every bit as much as the Rolling Stones are a bunch of rotating rocks.
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