Turning to Drugs for Heart Failure
While there have been setbacks in recent research, drugs remain the most common effective heart-failure treatment.
Reviewed By Michael Smith
Heart failure remains a serious and incurable disease, but heart-failure treatment with medications has been a tremendous success story. "I think that the drugs we've used have made an enormous impact on people with heart failure ," says Marvin A. Konstam, MD, chief of cardiology and director of cardiovascular development at Tufts-New England Medical Center. "That's something we shouldn't lose sight of."
Research into heart-failure treatment with drugs has suffered a few setbacks in recent years, as medications considered to have great potential did not prove as effective as hoped. Implantable devices like defibrillators, LVADs, and biventricular pacers are also generating a great deal of excitement as new ways to treat the condition.
But given the novelty and expense of implantable devices, it's likely that heart-failure treatment for most people will consist of drugs alone in the near future, according to Michael R. Bristow, MD, PhD, from the University of Colorado Health Sciences Center. The good news is that standard drugs for heart-failure treatment are effective and new ones are under development.
Heart-failure treatment with medication depends on a person's condition, whether you suffer from the more common systolic heart failure -- in which the heart has difficulty pumping -- or the rarer diastolic heart failure -- in which the heart is stiff and has trouble expanding to fill with blood.
Both conditions are helped by angiotensin-converting enzyme inhibitors (ACE inhibitors), which in the last decade have become the linchpin of heart-failure treatment. The success of ACE inhibitors in reducing sickness and death from heart failure demonstrated the significant role that hormones play in worsening heart failure and changed the focus of heart-failure treatment.
Some of the body's natural responses to a failing heart actually cause the condition to worsen. One is the body's release of hormones that constrict the blood vessels, making it harder for the weakened heart to pump blood. ACE inhibitors and other similar drugs block the effects of these hormones and widen the vessels, easing the heart's workload.
Beta-blockers are another prominent heart-failure treatment. In addition to lowering blood pressure and decreasing heart rate, these drugs also lessen the effects of the hormones that result from heart failure. Beta-blockers are tremendously useful drugs, resulting in almost a 50% reduction in the risk of death in people with heart failure.
Another common drug used in heart-failure treatment is diuretics, which help remove water and sodium from the blood. Still another drug, digoxin, is sometimes used to slow irregular heartbeats and increase the force of the heart's contractions. Depending on your condition, other medications may be necessary.
A possible substitute for people who cannot tolerate ACE inhibitors are angiotensin II receptor blockers (ARBs), which, like ACE inhibitors, affect the hormonal balance. Jay N. Cohn, MD, professor in the cardiovascular division at the University of Minnesota Medical School, led a major study of the ARB Diovan. He tells WebMD that he does not see ARBs as only a substitute for ACE inhibitors, but as a drug that can be used in combination with them when beta-blockers are not used. However, experts agree that ACE inhibitors, ARBs, and beta-blockers should not be taken together.
Some are less sure about the use of ARBs. "The ARBs should not, in my opinion, be routinely substituted for ACE Inhibitors," says Konstam. "Although they're linked by a common effect, they are different classes of drugs. While they look like they may be effective, for now they should be considered as second line treatment for heart failure."
Some of the most significant breakthroughs in drugs for heart-failure treatment have come from the aldosterone blockers, such as Aldactone (spironolactone), and more recently, Inspra. Like ACE inhibitors, these drugs work by affecting the hormones in the bloodstream, in this case, aldosterone, which can cause the retention of salt and water and other ill effects.
While Aldactone can have some unpleasant side effects -- such as impotence and gynecomastia (breast swelling in men) -- Inspra does not cause them. Both drugs can cause an increase in potassium levels, so patients need to be monitored. One significant difference between the drugs is price: Aldactone, having been around for decades as a high blood-pressure drug, is significantly cheaper than Inspra, which was approved in September 2002.
Bertram Pitt, MD, who has led major studies of both of these drugs for heart-failure treatment believes Aldactone may still be the best drug for those who aren't concerned about side effects. But for some, side effects are an important issue.
While the reduction in side effects is important, the greater significance of the study, according to Pitt, is that it demonstrates the importance of blocking aldosterone. The most recent study testing Inspra is the second that shows aldosterone blockade makes a difference, Pitt tells WebMD. "There were a lot of people on the fence before, and I think this study will lead to more clinical investigation."
More study of Inspra is needed since this drug has largely been studied in people who had suffered from a recent heart attack and not heart failure. But the results are exciting for people with heart failure, according to Konstam. "In the last 10 years of drug therapy, there have been three big stories," he says. "First were the ACE Inhibitors, then the beta-blockers in the mid-90s, and now the aldosterone [blockers]."
Aggressive Heart-Failure Treatment
Experts are consistently stressing the importance of treating heart failure aggressively.
If you look at the heart-failure trials over the last 15 years, combining ACE inhibitors, and beta-blockers with devices used in heart-failure treatment, the rate of death has dropped 68%, says Bristow. "That's spectacular progress."
"But that's only progress in clinical trials," Bristow tells WebMD. "The problem is that these effective treatments are not getting out to the community. There continue to be only about 50% to 60% of patients who should be on ACE inhibitors who are actually on them, and 30% to 40% of the people who should be using beta-blockers who are actually are."
Part of the problem is that beta-blockers can cause side effects and getting the right dosage can be difficult. As a result, doctors may be reluctant to prescribe them.
"Side effects can be problematic with beta-blockers since they can actually make you feel worse," says Susan Bennett, RN, DNS, an Indiana University nursing school professor.
Still, experts generally agree that heart-failure treatment has become more aggressive in recent years as the message has gotten to physicians. "Sure, there's always room for improvement," says Konstam. "But I see positive trends in the speed with which clinicians respond to new treatment information."
The Bulging Medicine Cabinet
A potential problem with the success of drugs for heart-failure treatment is that it means the number of drugs that people are taking has increased. When new drugs are developed, they are typically not compared in head-to-head studies with old drugs. As a result, old drugs don't get replaced; instead, the new drugs are often added to existing heart-failure treatment. This can add up to a lot of pills to swallow. The greater the number of pills, of course, the harder it becomes to stick to a drug regimen.