WEDNESDAY, April 2 (HealthDay News) -- Two well-known HIV drugs, abacavir and didanosine, appear to increase the risk of heart attacks, European researchers reported Wednesday.

Based on that data, the U.S. Food and Drug Administration is now conducting a safety review of the potential risks of both drugs.

Many people with HIV take a combination of antiretroviral drugs, which include a protease inhibitor and a nucleoside reverse transcriptase inhibitor such as abacavir or didanosine. Concerns have been raised about the cardiovascular effects of long-term use of these drugs.

"We have investigated a number of drugs used to treat HIV patients for whether they are associated with an altered risk of having a heart attack," said lead researcher Dr. Jens D. Lundgren, from the University of Copenhagen in Denmark. "We have identified [that] two of those drugs were indeed associated with an increased risk of a heart attack."

The actual risk of having a heart attack when using these drugs varies with whether a patient already has underlying risk for heart attack, Lundgren added. For example, a patient who is at risk for having a heart attack will increase his or her risk by 38 percent by using either abacavir or didanosine, he said.

"However, if you have a very small underlying risk of heart attack, the risk will only be slightly increased," Lundgren said.

The report was published Wednesday in the online edition of The Lancet.

In the study, Lundgren's team collected data on 33,347 HIV patients who participated in the Data Collection on Adverse Events of Anti-HIV Drugs study (D:A:D). Specifically, the researchers looked for a connection between HIV medications and heart attack.

For commonly used drugs called nucleoside reverse transcriptase inhibitors such as zidovudine, stavudine or lamivudine, the researchers found no association with an increased risk for heart attack.

However, the nucleoside reverse transcriptase inhibitors abacavir and didanosine were associated with an increased rate of heart attack, the researchers found. For patients taking abacavir, there was a twofold increased risk for heart attack. For those taking didanosine, the increased risk was about 50 percent.

For patients who stopped using these drugs, their risk for heart attack decreased within six months, Lundgren's group found.

"For those patients who have an increased underlying cardiovascular risk, then our suggestion is that these patients should consider whether there are other safer alternatives to these drugs," Lundgren said. "If there are safer alternatives, then patients should consider switching to those."

In a letter published in the same journal issue, GlaxoSmithKline, the maker of abacavir, said that their own analysis of 54 studies found no increase in the risk of heart attack from the drug.

GlaxoSmithKline spokesman Dr. Didier Lapierre wrote, "We did not find a result consistent with that of D:A:D... GSK takes the D:A:D finding seriously and is committed to understanding these data more fully and to communicating openly with treating physicians and regulatory agencies globally."

Didanosine is manufactured by Bristol-Myers Squibb.

Based on the data from D:A:D, the FDA said last week that it was conducting a safety review of both drugs.

"FDA continues to evaluate the overall risks and benefits of abacavir and didanosine. This evaluation may result in the need to revise labeling for the products. Until this evaluation is complete, health-care providers should evaluate the potential risks and benefits of each HIV-1 antiretroviral drug their patients are taking, including abacavir and didanosine," the agency said in a statement.

One expert thinks it's more important for patients to have their HIV under control; then they can worry about potential cardiovascular side effects.

"This is a surprising and provocative finding," said Dr. James Sosman, an associate professor of medicine at the University of Wisconsin School of Medicine. "We have not seen cardiovascular problems associated with abacavir."

Sosman noted that the use of antiretroviral drugs has replaced concerns about serious opportunistic infections in HIV patients with concerns about less serious risks like cardiovascular disease and diabetes.

"The most important thing for HIV patient is to control their HIV," Sosman said. "If they have excellent control with abacavir or didanosine, then you look for options to limit other risk factors. Patients not on HIV therapy have a higher risk of developing heart disease than people on HIV therapy," he said.

More information

For more on HIV, visit the U.S. National Institute of Allergy and Infectious Diseases.

TUESDAY, April 1 (HealthDay News) -- Putting external defibrillators in the homes of people after they had a heart attack didn't improve their survival rate, a new study found.

But, the leader of the study still sees plenty of encouraging news in the research and is not necessarily ruling out the use of those heart-shocking devices in the home.

In a 37-month trial, half of 7,001 heart attack survivors had defibrillators put in their homes, while the other half got standard instructions to call for emergency help if a second heart attack occurred. But, the death rate for both groups was just about the same -- 222 of the people given defibrillators and 228 of those not given the devices, said study leader Dr. Gust H. Bardy, director of the Seattle Institute for Cardiac Research.

The findings were to be presented Tuesday at the American College of Cardiology annual meeting, in Chicago, and were published in the April 1 online edition of the New England Journal of Medicine. The results were also expected to be published in April 24, 2008, print issue of the journal.

People in the study weren't considered suitable for implanted defibrillators. The devices they took home were identical to those now found in many public places for use in cardiac emergencies.

"It really amazed me that the survival prospects for this group were so promising," Bardy said. "A 2 percent-a-year death rate for 60-year-old patients, that surprises me."

Most of the deaths in the defibrillator group were due to non-cardiac causes, Bardy noted. "The event rate was so low," he said of cardiac deaths, "and the usage of the defibrillators is less than it should be. It's not that the devices are ineffective. When they were used, they did real well."

The defibrillators, which deliver an electric shock to restart an arrested heartbeat, were used 18 times, and six of those people survived, Bardy said. "Long-term survival of one out of three is not bad," he said.

Partly because of the high cost of external defibrillators, their home use should not be encouraged, said an accompanying editorial in the journal by Dr. David J. Callans, professor of medicine at the University of Pennsylvania. "Future efforts should turn toward education, modification of risk factors and other methods for primary prevention of heart disease," Callans said in a statement.

But Dr. Robert Femia, chairman of emergency medicine at Lenox Hill Hospital in New York City, disagreed with Callans. "Early defibrillation offers the best chance for survival," Femia said. "My point is that there may be a role for a defibrillator as part of a plan developed by your physician on an individual basis."

Such a plan usually is lacking after a heart attack, Bardy said. "One thing that is not standard practice is consciousness-raising," he said. "Most post-myocardial infarct [heart attack] patients don't have a discussion of mortality, don't have a discussion of cardiac arrest, don't have a discussion of what to do if there is a cardiac arrest."

Any discussion with a doctor after a heart attack should include advice about carefully taking any medications that are prescribed, Bardy said, and about other medical measures needed to keep arteries clear.

When such steps are taken, he said, "the patient may or may not choose an external defibrillator. I see no downside for an external defibrillator. Whether or not it will help in the long run, I don't know."

More information

The facts about external defibrillators are available from the U.S. Food and Drug Administration.

MONDAY, March 31 (HealthDay News) -- For patients with blockages in the left main coronary artery, percutaneous coronary intervention -- PCI, often referred to as angioplasty -- may be a viable alternative to bypass surgery.

"We focused on all-cause mortality and found no difference between PCI and surgery," Dr. Seung-Jung Park, senior author of the study and director of interventional cardiology at Asan Medical Center in Seoul, South Korea, said at a news conference.

However, the study also found that PCI patients who received stents -- tiny wire-mesh tubes used to prop open an artery -- had much higher rates of revascularization, a procedure needed to reopen arteries that had become clogged again. Bare metal stents had the highest rate of revascularization, the study found.

The findings were presented Monday in Chicago at a meeting of the Society for Cardiovascular Angiography and Interventions, in partnership with the American College of Cardiology, and published simultaneously March 31 in the New England Journal of Medicine.

The left main coronary artery provides most of the blood to the heart's left ventricle. Current guidelines recommend coronary artery bypass grafting (CABG) over percutaneous coronary intervention unless a previous graft has been performed.

And until more studies are conducted, CABG should remain the treatment of choice in these patients, the study authors stressed.

Percutaneous coronary intervention, which refers to a number of procedures used to treat arteries, is usually reserved for patients who aren't good candidates for surgery or who are protected by a previous bypass graft. A typical form of PCI -- angioplasty -- involves inserting a catheter into the artery to widen the vessel, and then hold it open with a stent.

But the development of coronary-artery stenting, especially with drug-eluting stents, has led researchers to reassess the role of PCI. Drug-eluting stents slowly release drugs that help keep the artery open.

Currently, there is limited long-term data comparing CABG and percutaneous coronary intervention with stents in patients with left main coronary artery disease.

For the new study, Park and his team compared 1,102 patients with unprotected left main coronary artery disease who underwent stent implantation (318 with bare metal stents and 784 with newer drug-eluting stents) with 1,138 patients who underwent CABG as 12 centers in Korea.

Overall, there were no major differences between the two groups in the risk of death or the risk of an outcome that included heart attack and stroke.

The next step, Park said, is a randomized trial comparing the two procedures.

More information

The American Heart Association   has more on percutaneous coronary intervention.

THURSDAY, Feb. 21 (HealthDay News) -- A moderate level of aerobic fitness can significantly reduce stroke risk in men and women, according to a large, long-running study.

The study, expected to be presented Thursday at the American Stroke Association's International Stroke Conference in New Orleans, showed 30 minutes or more of brisk walking, or an equivalent aerobic activity, five days a week could lower stroke risk by about 40 percent.

Fitness has a protective effect regardless of the presence or absence of other stroke risk factors, including family history of cardiovascular disease, diabetes, high blood pressure, elevated cholesterol levels and high body mass index, study author Steven Hooker said in a prepared statement.

This study is the first to suggest there may be a significant independent association between cardiorespiratory fitness (CRF) and fatal and nonfatal stroke in men and nonfatal stroke in women, said Hooker, director of the Prevention Research Center at the University of South Carolina Arnold School of Public Health.

About 780,000 U.S. adults suffer a stroke each year, and stroke is a leading cause of serious, long-term disability in the United States, according to the American Stroke Association. About 150,000 people die from strokes annually, making it the nation's No. 3 cause of death.

Researchers analyzed data on more than 60,000 people -- 46,405 men and 15,282 women -- who participated in a long-term study at the Cooper Aerobics Center in Dallas between 1970 and 2001. The participants, aged 18 to 100 and free of known cardiovascular disease when they entered the study, were followed for an average of 18 years. During that time, 863 people -- 692 men and 171 women -- had strokes.

Upon entering the study, each participant took a test to measure cardiorespiratory fitness in which they walked on a treadmill at an increasing grade and/or speed until they reached their maximal aerobic capacity.

Men in the highest quartile (25 percent) of CRF had a 40 percent lower relative risk of stroke compared with men in the lowest quartile. That difference stayed constant even after adjusting for other factors such as smoking, alcohol intake, family history of cardiovascular disease, body-mass index (an estimation of body fatness), high blood pressure, diabetes and high cholesterol levels, Hooker said.

Among women, those with a higher cardiorespiratory fitness level had a 43 percent lower relative risk than those in the lowest fitness level.

The overall stroke risk dropped substantially at the moderate CRF level, with the protective effect persisting almost unchanged through higher fitness levels.

"We found that a low-to-moderate amount of aerobic fitness for men and women across the whole adult age spectrum would be enough to substantially reduce stroke risk," Hooker said.

Physical activity is a major modifiable cardiovascular disease risk factor. Increasing the nation's CRF through regular physical activity could be a vital weapon to lower the incidence of stroke in men and women, he said.

One of the study's limitations is that most of the participants were white, well-educated and middle-upper income, Hooker said. He recommended that data be collected from other populations.

More information

To learn more about improving your cardiovascular fitness level, visit the American Heart Association  .