Medical Mysteries of the Heart » 420MedBook Social Network
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Posted: 2015-07-04 04:00:00
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Credit Eleanor Taylor

Scientists have made enormous gains in reducing deaths from coronary heart disease, the leading cause of heart attacks, but it is astonishing how much they still don’t know. That leaves patients and their doctors uncertain about the best way to fight a disease that is still the leading cause of death for both men and women in the United States.

The successes and remaining puzzles in treating heart disease were laid out in recent articles by The Times’s Gina Kolata. From 2003 to 2013, the death rate from coronary heart disease plunged by about 38 percent, thanks to better control of cholesterol and blood pressure, a decline in smoking rates, improved medical treatments and faster care of people after a heart attack.

The most surprising gaps in knowledge involve two of the most common treatments: when to use stents — small wire cages — to prop open coronary arteries and how far to drive down blood pressure.

Stents save the lives of people having heart attacks, but there is no convincing evidence that they prevent heart attacks in people suffering chest pain because of a partially blocked coronary artery. The cholesterol-lowering drugs known as statins, under some theories, might do as much to reduce pain. Unfortunately, belief in stents is so ingrained among cardiologists and patients that it has been difficult to recruit enough people for a study comparing the treatments.

Researchers also need to find out more about just how low blood pressure needs to be to prevent heart attacks, strokes and other ill effects. A clinical study of 9,000 adults with high blood pressure being conducted now might offer some answers when results are in, probably in 2017. Half of the participants were told to reduce their systolic blood pressure — the top number — to below 120 by using common medications, while the other half aimed for below 140. The importance of diet and exercise and of risk factors like family history in determining optimal blood pressure for an individual still needs more research.

Some recent studies have found new practices that make a significant difference to the outcome for heart attack patients. In a multiyear analysis, Yale researchers found that some hospitals reduced the time between when a patient suffered a heart attack and had a clogged artery opened by changing emergency room procedures.

Without relying on new technology, they altered protocols, like having paramedics transmit an electrocardiogram to the emergency room; having emergency room doctors rather than a cardiologist decide whether a patient was having a heart attack; and summoning all members of a heart attack team with a single phone call. These common-sense ideas reduced the time before treatment to less than an hour for most patients from two hours or more.

Improvements in surgical techniques are also saving lives in cases that would not have been possible before. This has been true with one procedure that has become a preferred treatment for patients suffering from severe aortic valve stenosis, an often fatal condition involving the narrowing of a valve controlling blood flow from the heart. Some 100,000 Americans have this condition but are too old or sick for open-heart surgery to replace the valve. Now, many such patients are being saved by threading a catheter through a blood vessel and using it to insert a new valve, made of cow or pig tissue, without removing the old one. Some experts believe this will become the standard treatment for most patients with the disease, not just those who are frail.

Further gains in heart treatment may come from breakthrough medicines that are being tested. A panel of experts recommended last month that the Food and Drug Administration approve two drugs that reduce so-called bad cholesterol to remarkably low levels for patients in whom statins don’t work well. The recommendations were based on highly encouraging preliminary data, with large clinical trials ending in 2017. Making sure that there are no unexpected risks in lowering cholesterol to such levels will require more hard data.

In this and other cases, more data can help doctors and patients overcome ingrained resistance to new medical approaches.

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