|
|||||||
|
|
|
|||||
|
|
|||||||
|
|||||||
|
|
|
|||||
|
|
|||||||
RALEIGH, N.C.--(BW HealthWire)--May 18, 1999--
American Society of Echocardiography Member Recommends Screening of Family Members
The use of echocardiography to screen relatives of patients with Marfan's syndrome could decrease the number of deaths from aortic dissection or aneurysm, according to a recent editorial published in The New England Journal of Medicine. The availability of echocardiograms and other non-invasive screening methods in addition to improved surgical techniques have resulted in a nearly 25-year increase in life expectancy for patients with Marfan's syndrome in the last three decades.
"Because ascending aortic aneurysm (whether or not it is relatedto Marfan's syndrome) commonly affects more than one family member, screening of a patient's relatives can identify additional patients who may benefit from preventive treatment," said Dr. Richard B. Devereux, professor of medicine at Weill Medical College of Cornell University and member of the American Society of Echocardiography in the April 29 editorial.
Marfan's syndrome affects the body's connective tissues and causes complications in the eyes, skeleton, heart and blood vessels.
Enlargement of the aorta, the major artery that carries blood from the heart to the body, is often accompanied by tearing of the inner lining -- a condition called aortic dissection. This is the leading cause of death for patients with this genetic syndrome. It occurs because the aorta may be so stretched that its walls weaken, leaving it prone to the tearing of the lining, or rupture of the aorta. Either occurrence is a medical emergency, and can be fatal if not rapidly corrected.
"Echocardiograms have played a major role in the dramatically improved the life expectancy of patients with Marfan's syndrome," according to Dr. Devereux. Echocardiography is the ultrasound examination of the heart. It provides a view of the heart and major blood vessels and is key for diagnosing aortic enlargement and dissection. Because Marfan's syndrome is genetic, there is an increased chance that close relatives could also be affected, even if they don't have other common characteristics of the disorder, such as very long limbs, tall stature or being double-jointed.
Echocardiography provides an effective screening mechanism that is non-invasive and risk-free for the patient. If the echocardiogram shows an enlarged aorta, doctors can begin treatment to lower arterial pressure, which could help prevent damage to the aorta. Echocardiography also can help determine if surgery is needed to repair the aorta. Echocardiography also is essential for rapid diagnosis of aortic dissection in emergency situations. Once a dissection occurs, the mortality or risk of death increases one percent per hour.
Transesophageal echocardiography, which is conducted through the esophagus with a transducer on a flexible swallowing tube, provides the most detailed view of the aorta. This test can be performed rapidly in the emergency department. It provides critical information about the site and extent of dissection and the need for urgent life saving surgery.
The American Society of Echocardiography is a professional organization dedicated to the certification and continuing education of medical professionals who work in the field of echocardiography, including cardiologists and cardiac sonographers. The organization was founded in 1975. The American Society of Echocardiography will hold its annual meeting June 13-16 in Washington, D.C.
An adaptation to MRI noninvasively enables radiologists to distinguish between a type of plaque in the coronary arteries that is likely to cause a heart attack and plaque that isn't.
-- There is hard, more stable plaque and soft 'vulnerable' plaque, which causes 70 percent of heart attacks.
-- Heart disease is the leading cause of mortality in the United States. As many as 1.5 million Americans will have a heart attack this year, and about one-third of them will die.
CHICAGO, Dec. 3 /PRNewswire/ -- An adaptation to magnetic resonance imaging (MRI) that can noninvasively show "soft" plaque in the coronary arteries may have far-reaching ramifications for identifying people at high risk of heart attack, according to preliminary research being presented here today at the 85th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA).
"In 70 percent of people who have heart attacks, the cause is 'vulnerable plaque,' which is soft and is more likely to rupture than hard, stable plaque," said Zahi A. Fayad, Ph.D., assistant professor of radiology and director of cardiovascular imaging, physics and research at Mt. Sinai School of Medicine, New York. Dr. Fayad and his team developed a modification of MRI that can clearly look inside the coronary arteries. "This could change the face of cardiac imaging. The only other technology that can actually look at the type of plaque on the walls of the arteries is intravascular ultrasound (IVUS), which is invasive, and the pictures are not nearly as good."
Heart disease is the leading cause of mortality in the United States. As many as 1.5 million Americans will have a new or recurrent heart attack this year, and about a third of them will die, according to the American Heart Association.
In the Mt. Sinai study, 13 subjects underwent MRI: 8 healthy subjects and 5 who had been determined by X-ray angiography to have heart disease. The study specifically looked at 5 arteries in each of the latter group that had blockage of 40 percent or more. Preliminary findings showed that plaque build-up in the heart patients was 2 to 10 times thicker than in the healthy subjects, and that the plaque bulged in some places, indicating the more dangerous, vulnerable plaque. The study showed that it is possible to visualize the shape of the plaque inside the arteries, and that even though blood flow may be adequate in arteries with plaque buildup, having vulnerable plaques puts patients at risk for heart attack, and should be treated.
In the last decade, researchers have found that some plaques are more vulnerable to breaking off from the walls of the artery and prompting a blood clot, which travels to the heart and can cause heart attack. This so-called vulnerable plaque is soft because of its high lipid, or fat, content.
Treatment includes life-style changes, such as diet and exercise; the new lipid-lowering drugs; angioplasty and coronary bypass surgery. It's unclear why certain people may be more prone to developing vulnerable plaques, but it's believed to be related to a number of factors, including diet and genetics. Smoking, hypertension, high cholesterol and diabetes are believed to injure the artery walls, causing plaque to build up. Some plaques become harder and less risky, while other plaques apparently stay soft because there is too much of a cholesterol build-up, said Dr. Fayad.
"MRI also might be used to see if treatment is working, and to help determine whether other measures need to be taken," said Dr. Fayad. "It also may tell us when the plaque is stable, and that perhaps in some cases, no therapy is needed."
MRI uses no radiation, creating images based on the water content and chemical composition of the structures within the body. The MRI in this study involves using an enhanced cardiovascular magnet found at most heart centers and teaching hospitals. The enhanced MRI is fast enough to image a beating heart.
SOURCE The Radiological Society of North America
ANN ARBOR, Mich., July 19 /PRNewswire/ -- A new study -- led by a leading University of Michigan heart researcher and made public today by the New England Journal of Medicine (NEJM) -- shows that adding an established medication to standard treatment regimens for heart failure reduced deaths by 30 percent. While the article will not appear in the journal until later this year, the life-saving potential of the information caused the editorial staff to post the findings on its Internet site, http://www.nejm.org.
The NEJM posts an early release of a manuscript on its web site only two or three times a year in accordance with its Ingelfinger Rule, which allows the early release of findings determined to have immediate clinical implications. Such is the case in this heart failure study, where researchers observed a substantial reduction in mortality for a disease that, in the U.S. alone, affects as many as 4.7 million people and results in approximately 250,000 deaths annually, according to the American Heart Association.
The study looked at the effect of adding Aldactone(R) (spironolactone), a drug that has been used for decades to treat a variety of conditions but had not been tested previously as therapy for reducing deaths in heart failure patients.
Known as the Randomized Aldactone Evaluation Study (RALES), the trial defies current thinking that spironolactone and other drugs that block the action of a hormone known as aldosterone should not be administered in conjunction with an ACE (angiotensin-converting-enzyme) inhibitor.
"Not only was combination therapy with Aldactone and ACE inhibitors well tolerated by patients in the most severe stages of heart failure, but the decrease in cardiac death and hospitalization was dramatic," said lead investigator Bertram Pitt, M.D., professor, Division of Cardiology at the U-M Medical School. "These findings suggest that the gold standard treatment for severe heart failure should include an aldosterone receptor antagonist."
In the RALES study, investigators compared a standard treatment regimen of an ACE inhibitor and a diuretic, with or without digoxin added to this regimen, plus Aldactone or placebo in patients with severe heart failure. Patients were followed for a mean of 24 months.
Impact of Heart Failure :
American Heart Association statistics indicate that an estimated 400,000 new cases of heart failure are diagnosed each year. Worldwide, it is estimated that 20 million people suffer from this condition. For people with heart failure, the five-year mortality rate is estimated at 50-60 percent. In addition to the number of deaths directly attributed to heart failure, this serious and prevalent illness is an indirect, contributing cause of more than one million deaths. For heart failure patients, sudden death occurs at six to nine times the rate expected in the general population. Even patients with mild symptoms face an annual mortality rate of 10-20 percent.
There are many known causes leading to heart failure, including coronary heart disease, high blood pressure and cardiomyopathy. While treatment varies depending on the etiology and stage of heart failure, most therapeutic protocols include lifestyle changes as well as drug therapy.
The RALES study, sponsored by Searle, was conducted in Belgium, Brazil, Canada, France, Germany, Japan, Mexico, the Netherlands, New Zealand, South Africa, Spain, Switzerland, Venezuela, the United Kingdom and the United States. Because of the global nature of the RALES study, and the large number of study sites in Europe, the Aldactone used in the trial was the formulation approved in many European countries.
Chairs: Harvey Feigenbaum, MD, and A. Jamil Tajiik, MD
Authors: Arthur J. Labovitz, MD, and Stephen Phlaum, MD
Embolic Stroke and Echocardiographic Findings - What Are the Implications?
Arthur J. Labovitz, MD, St. Louis, Missouri
Stroke continues to represent a major cause of mortality and morbidity in the United States despite significant advances in the detection and treatment of cardiovascular disease. The etiologies of stroke are multiple and include atherosclerotic cerebral vascular disease, cardiac disorders, and hematologic disorders. Several large databases have examined the primary or suspected etiology of ischemic stroke. Atherosclerotic cerebral vascular disease is the most common etiology, accounting for anywhere between 15% and 40% of all cerebral ischemic events. Cardiac disorders follow closely as an etiology for ischemic stroke, representing 15% to 30% of all events. The etiology of up to 30% of all ischemic strokes remains unknown and may, in fact, be secondary to cardioembolic abnormalities.
There are clearly a number of cardiovascular abnormalities associated with cardioembolic stroke. These include atrial fibrillation, valvular heart disease, left ventricular dysfunction, and pathology associated with hypercoagulable states. In assessing the patient with ischemic stroke and suspected thromboembolic etiology, it is important to identify these associated clinical syndromes as well as to identify structural abnormalities that may predispose to the development of intracardiac thrombus. Furthermore, the ability to visualize an intracardiac thrombus directly is important in establishing a definitive cause for ischemic stroke.
It has been approximately 10 years since transesophageal echocardiography (TEE) was introduced into clinical practice in the United States. During that time, this technique has established itself as the imaging modality of choice for the evaluation of patients with known or suspected cardioembolic stroke. This is because TEE offers a method for examining regions of the heart often implicated in cerebral embolic events of cardiac origin, including superior resolution of the left and right atria and their appendages, the interatrial septum, cardiac chambers, and thoracic aorta. Because of this, in many busy echocardiographic laboratories, evaluation of patients for cardiac source of emboli may represent 25% to 50% of all patients examined by this technique.
A number of studies have documented TEE to be highly sensitive and specific for identification of intracardiac thrombus. In patients with cerebral ischemia of unknown etiology, left atrial thrombus has been reported to be identified by TEE in as many as 10% to 25% of the patients studied. The latter occurs in patients with atrial fibrillation. Additional abnormalities of left atrial function -- including spontaneous contrast in the left atrium and decreased velocities in the left atrial appendage, both representing a low-flow state -- have been shown to be associated with cerebral ischemic events. Abnormalities of the interatrial septum have also received substantial attention in the evaluation of such patients.
Aneurysms of the interatrial septum as well as shunting through a patent foramen ovale have both been identified with increased frequency in the group of patients with unexplained cerebral ischemia. Multiple factors, including atrial-septal aneurysm and clinical risk factors associated with early and marked shunting, have all been shown to risk-stratify those with patent foramen ovale and potential paradoxical emboli.
Finally, complex atheroma of the thoracic aorta has been identified as a major risk factor in cardioembolic stroke. Lesions that extend >4 mm into the lumen of the aorta or those with mobile components have been seen in multiple studies as related to otherwise unexplained stroke in this patient population.
A recently reported multicenter study evaluated 792 patients with otherwise unexplained cerebral ischemia. Transesophageal findings of a potential etiologic cause were present in approximately 60% of the patients studied. Although the intracardiac thrombus did not predict recurrent stroke (presumably on the basis of aggressive anticoagulant therapy), it could predict subsequent mortality with a 3-fold increase in 1-year mortality over those without intracardiac thrombus.
The questions of whether identification of these abnormalities affects outcome and, if so, whether they are cost-effective, are more difficult ones. Clearly, systemic anticoagulation is indicated in patients with intracardiac thrombus. Unfortunately, the side-effect profile of warfarin in a large number of patients with relative contraindications to anticoagulant therapy does not allow indiscriminate anticoagulation of this patient population. Furthermore, preliminary evidence suggests that a subset of these patients should perhaps receive more intensive anticoagulation therapy than others. Finally, few data exist from randomized trials to help determine whether antiplatelet therapy may be sufficient in subsets of patients presenting with otherwise unexplained cerebral ischemia.
In summary, TEE evaluation will identify potential etiology of cerebral ischemia in up to 60% of the patients studied. However, only a minority of these studies will reveal the presence of intracardiac thrombus for which definitive therapy is well described. These examinations do offer prognostic information independent of the method of treatment; however, more study is needed to determine the ultimate implications of these examinations in terms of clinical outcomes and cost.
Should Transesophageal Echocardiogram Be Performed in All Patients With Atrial Fibrillation?
Michael H. Crawford, MD, Albuquerque, New Mexico
A number of multicenter studies have been performed over the past decade and have clearly documented the superiority of systemic anticoagulation in the primary prevention of stroke in patients with nonvalvular atrial fibrillation. In light of these findings, controversy exists as to the exact role of transesophageal echocardiography (TEE) in patients with atrial fibrillation.
The results of the Stroke Prevention in Atrial Fibrillation (SPAF) III study appear to suggest that TEE may be useful in risk stratifying patients with nonvalvular atrial fibrillation. Patients with left atrial thrombus, spontaneous contrast in the left atrium, and decreased velocities in left atrial appendage all appear to be at higher risk for thromboembolic events. Likewise, demonstration of complex aortic plaque by TEE also appears to identify a high-risk population of patients with atrial fibrillation. Furthermore, recent reports have suggested that TEE can be used prior to cardioversion in order to shorten the course of precardioversion anticoagulation, and in the 65- to 75-year-old age group without clinical risk factors, to assess the type and intensity of anticoagulation.
Is Contrast Echo Worth the Expense?
Anthony N. DeMaria, MD, San Diego, California
The FDA approval of octafluoropropane (Optison) echo contrast in 1998 ushered in a new era in cardiovascular ultrasound imaging. These new contrast agents are administered intravenously and, as such, pass through the pulmonary circulation to opacify the left ventricle. This enhances endocardial border identification, with resultant improvement in the evaluation of left ventricular function, particularly in patients with suboptimal noncontrast echocardiograms. In addition, the sensitivity, specificity, and accuracy of stress echocardiography are enhanced by contrast opacification of the left ventricle.
Administration of these agents, however, has a cost above and beyond the purchase price of the echo contrast agent alone; that cost includes insertion of an intravenous line and training of the personnel involved in the administration and interpretation of these studies.
Preliminary results suggest, however, that the improved diagnostic accuracy afforded by contrast echo will ultimately prove cost-effective in the overall management of patients with cardiovascular disease by reducing subsequent referral for other diagnostic studies such as TEE, cardiac catheterization, and nuclear scintigraphy. Furthermore, it is likely that these agents will provide yet another means of evaluating myocardial perfusion in patients with known or suspected ischemic heart disease.
When Should Stress Echo Be Performed Post Myocardial Infarction?
William Armstrong, MD, Ann Arbor, Michigan
Echocardiographic imaging performed in conjunction with either exercise or pharmacologic-induced stress offers several distinct advantages in the post-myocardial infarction (MI) population, both from a prognostic and diagnostic standpoint. Improvement on wall motion during low-dose dobutamine infusion in a segment that is hypokinetic at rest is highly predictive of viable myocardium in the distribution of the stenotic coronary artery. Several studies have indicated that echo stress testing can be safely performed within a few days following myocardial injury. However, diagnostic accuracy appears to be directly related to the time from MI.
Recent studies have shown stress echogram to be as valid as single-photon emission computerized tomography (SPECT) imaging and positron-emission tomography (PET) scanning in the assessment of myocardial viability, and an excellent predictor of myocardial recovery following revascularization after MI.
Stress echogram is currently recommended as a class IIa indication in the AHA/ACC Guideline for acute MI, as it is useful, beneficial, and cost-effective.
Valve Surgery: When Does Echo Assessment Suffice?
Blasé A. Carabello, MD, Houston, Texas
Doppler echocardiographic examination has become the cornerstone of noninvasive assessment of individuals with known or suspected valvular heart disease. Since the first clinical application of Doppler echocardiography >2 decades ago, this technique has served as a gold standard in the quantitation of both regurgitant and stenotic lesions. Furthermore, evaluation of ventricular function and size provides important information concerning the timing of surgery, prognosis, and the optimal type of intervention to be used, in many cases. Assessment for a mitral valve repair, for instance, would be difficult -- if not impossible -- without echocardiographic evaluation.
It is only in selected circumstances where symptoms, physical exam, and echocardiographic evaluation of left ventricular geometry and severity of disease are so discordant or confusing that invasive study would provide key information in managing the patient with valvular disease. It is important to note that if the invasive procedure is necessary, it must be carefully performed, complete, and accurate to be of maximum value.
By LINDA A. JOHNSON
.c The Associated Press
Researchers say they have found a better way to predict a heart patient's risk of early death than the expensive, high-tech tests most doctors swear by: an often-ignored measurement taken during routine treadmill ``stress tests.''
The heart's recovery rate - how much the heartbeat slows after someone exercises to exhaustion and stops - can help doctors spot patients needing aggressive treatment for heart disease, the nation's biggest killer, according to Cleveland Clinic researchers.
Their findings also could spare healthier patients risky follow-up tests and procedures.
``It's already changed my clinical practice,'' said Dr. Michael Lauer, lead researcher and director of the Cleveland Clinic's exercise laboratory. ``It's terrific news.''
The study is reported in today's New England Journal of Medicine.
Exercise stress tests, used since the 1960s, involve having a patient walk on a treadmill while his or her heart rate, blood pressure and the heart's electrical currents are monitored. The test costs about $600.
Since the mid-1980s and early '90s, however, doctors have used more sophisticated tests also involving a treadmill: stress echocardiograms, or ultrasound images of the heart pumping, costing around $1,500; a nuclear imaging technique called thallium scintigraphy, costing about $2,400; and a nuclear ``video'' showing sections of the heart that are not pumping properly.
Normally, when someone exercises to exhaustion and then stops, the heart rate drops 15 to 25 beats per minute. Lauer and colleagues found that for patients whose heart rate fell less than 12 beats one minute after exercising, the risk of dying within six years was four times greater than for those above the cutoff.
``That was the number that best discriminated between people who were going to live and people who were going to die,'' Lauer said.
Normally doctors focus on other results from a treadmill test: how the patient feels, his endurance, how much his heart rate increases and changes in the heart's electrical currents.
Dr. Gerald Fletcher, a professor at the Mayo Medical School in Jacksonville, Fla., said the study convinced him doctors should add heart-rate recovery to those four factors to get the best picture.
``We have so many sophisticated tests to do that we sometimes overlook the obvious,'' Fletcher said.
The researchers studied records from standard treadmill stress tests of 2,428 adults treated at the clinic for suspected heart problems from 1990 through 1993.
The researchers found 19 percent of patients whose heart slowed less than 12 beats per minute in the first minute after exercise were dead within six years. Of those with a normal heart-rate recovery, only 5 percent died in that time.
After adjusting for the patients' age, medication use, heart rate during exercise and at rest, and other factors, the patients with abnormally low heart-rate recovery still were twice as likely to die.
``That may throw a flag up that maybe this person's at greater risk and they need to be watched closely,'' said John Jakicic, a professor at Brown University School of Medicine.
Lauer said the recovery rate as measured by a treadmill test was twice as good as thallium scintigraphy at predicting death.
Patients who are thought to have heart problems during initial testing sometimes undergo heart bypass operations or angioplasty, in which a tiny balloon is threaded into an artery to clear away a clog. These procedures can cost tens of thousands of dollars, and the complications can include bleeding, heart attack, stroke and death.
Heart-rate recovery could be an indicator of some other risk factor, given that scientists don't fully understand how hormones and electrical signals from the brain tell the heart when to speed up or slow down, said Dr. Edward Dwyer, chief of cardiology at New Jersey Medical School in Newark, N.J.
.c The Associated Press
By ANDREW BUCHANAN
CHICAGO (AP) - Cocaine delivers a ``double whammy'' to the blood stream that may explain how the drug triggers heart attacks in its users, a new study concludes.
Cocaine use ``is even more dangerous than we had previously known,'' said Dr. Arthur Siegel, the study's lead author. ``Every time a person uses it, it's like a little bit of Russian roulette.''
Cocaine causes blood to thicken by increasing the number of red blood cells, and by triggering an increase in a protein that causes platelets to stick together, according to the study in today's issue of the Archives of Internal Medicine.
The ``double whammy'' can cause clotting that can lead to heart attacks and strokes, said Siegel, chief of internal medicine at McLean Hospital outside Boston.
A previous study, released in June, showed cocaine users are 24 times more likely to have a heart attack during the first hour after taking the drug. The new study may help explain why, Siegel said.
His study measured changes in the blood of 21 people for an hour after they sniffed a moderate amount of cocaine, or received it intravenously.
Red blood cell counts increased 4 to 6 percent on average after individuals ingested the drug, due to constriction of the spleen. Cocaine causes the constricting by pumping more red blood cells into the system, Siegel said.
The thickened blood must circulate through already-constricted vessels, creating a potentially dangerous situation, Siegel said. Previous studies have shown that cocaine use causes blood vessels to narrow.
The study suggests that anticoagulants may be useful in treating cocaine-induced chest pains, Siegel said. He said it provides further warning to athletes who might use cocaine, or substances with a similar effect, in an attempt to enhance performance.
While the study's small sample size made the conclusions preliminary, ``we're very confident that both of these observations are real,'' he said.
The study also found an average 40 percent increase in a blood protein known as the von Willebrand factor in subjects who received cocaine intravenously. The von Willebrand factor promotes clotting by causing platelets to stick together.
Dr. Steve Frohwein, a cardiologist and assistant professor at the Emory University School of Medicine in Atlanta said several factors - such as infection, cancer or other toxins - can lead to clotting.
``Cocaine just stimulates a well known cascade of events,'' said Frohwein, who was not involved in the study.
.c The Associated Press
By BRIGITTE GREENBERG
When the main artery that carries blood from the heart tears, the victim
is more likely to survive if doctors patch the hole rather than try to sew
it closed or treat it with drugs, studies suggest.
The research, published in Thursday's New England Journal of Medicine, represents
the first look at whether a stent -- a wire-mesh tube that is inserted into
the artery in a non-surgical procedure -- is more effective than surgery
or drugs.
Each year in the United States, up to 5,500 people suffer from what is known
as an aortic dissection, a tear in the aorta that can get larger. A burst
aorta, if left untreated, is usually fatal.
Surgery and drugs are the standard treatments, but they have high rates of
failure and can themselves result in death.
The study by Dr. Christoph A. Nienaber and colleagues at University Hospital
Eppendorf in Hamburg, Germany, looked at 12 patients who received stents
and 12 who had surgery.
Surgery involves sewing the tear closed. To insert a stent, doctors thread
a catheter -- a long, flexible tube -- into the artery and push the stent
into place.
Among those who received stents, there were no deaths
or serious complications, such as stroke, paralysis in the legs, or a blood
clot that travels to the lungs. Among those who had surgery, four died as
a result of the operation itself and five suffered serious complications
within the following year.
A second study, by Dr. Michael D. Dake and colleagues at Stanford University,
looked at stents in 19 patients. Sixteen lived, and three died. Over the
next year, there were no other deaths or cases of rupture.
``This is a very attractive potential treatment that may represent a shift
in the way we manage this very complex disease,'' Dake said. ``Now there
is an alternative.''
In an accompanying editorial, Dr. Gus. J. Vlahakes of the Massachusetts General
Hospital cautioned that more research is needed.
Some people are genetically predisposed to suffer an aortic rupture. High
blood pressure can also contribute to a burst aorta.
Back to The WAVE~~~