Women With Chest Pain Gain Insight With New Test

A new, noninvasive test shows potential for helping women with unexplained chest pain, according to a study published in the medical journal Circulation: Journal of the American Heart Association.

The test points out those women whose hearts are deprived of oxygen -even when standard tests show no coronary artery disease.

Women often seek medical help for chest pain, sometimes undergoing coronary angiography. But in almost half of all such women, there is no coronary artery disease found.

Tests Open New Avenues

Now scientists suggest that blockages in the smaller, slender arteries that feed the heart muscle - blockages that cannot be spotted on standard tests - might be at fault.

"We have seen that many of these women are admitted to the hospital for chest pain, and undergo angiography to look for coronary artery disease [CAD] behind the angina, yet no such disease is found," says Dr. Gerald M. Pohost, at the Keck School of Medicine of the University of Southern California.

"Our results indicate that in many of these women, something is keeping the heart from getting the oxygen it needs," says Dr. Pohost, senior author on the study.  "We suspect microvascular dysfunction or disease."

Prompted by symptoms such as chest pain, or angina, more than a half million US women underwent coronary angiography to look for CAD in 2001.

Yet nearly half of women with chest pain who undergo coronary angiography are found to have no significant CAD, posing a puzzle for physicians.

CAD is a disease of the arteries that supply blood to the heart muscle. Over time, as fatty materials collect in the vessels that supply the heart, the artery walls thicken and narrow the space where blood can flow, depriving heart tissue of oxygen.

The study was a part of the Women's Ischemia Syndrome Evaluation, or WISE, study. WISE is a four-center study of women undergoing coronary angiography for chest pain or suspected myocardial ischemia.

The researchers compared 352 women with CAD to 74 other women without it. The CAD-free women underwent an imaging scan called phosphorus-31 nuclear magnetic resonance spectroscopy, which is done completely from outside the body.

The technique simply required that women squeeze a handgrip while lying inside an MRI unit. Nuclear magnetic resonance spectroscopy technology enabled scientists to measure levels of two phosphates found in heart tissue.

This was done once while women were at rest and again while they were squeezing the handgrip (experiencing physical stress).

Investigators then compared the before-and-after levels of the two phosphates.

Researchers saw that the ratio of the two phosphates (phosphocreatine and ATP) declined significantly in 14 of the 74 CAD-free women when they squeezed the handgrip. A big drop in the ratio is abnormal and a sign that heart tissue is not getting enough blood, Dr. Pohost explains.

Investigators wanted to see whether the abnormal results were linked to women's cardiovascular health.

Researchers Follow Women's Experiences

Over the next three years, they tracked how many of the women experienced a cardiovascular event such as a heart attack, stroke, or hospitalization for a blood clot or unstable angina.

They found that 87 percent of the CAD-free women with normal magnetic resonance spectroscopy results stayed free of cardiovascular events.

But 57 percent of the CAD-free women with abnormal magnetic resonance spectroscopy results had no events. That is not much better than the women who had been diagnosed with CAD: 52 percent of them avoided cardiovascular events during that time period.

Most of the events were hospitalizations due to unstable angina, and many of the women with abnormal magnetic resonance spectroscopy results experienced repeated, fruitless angiography procedures to find the cause of the angina during the three-year follow-up.

In the clinic, Dr. Pohost and fellow cardiologists use standard angina therapies to treat chest pain in these CAD-free women, he says.

The study suggests that magnetic resonance spectroscopy could be widely used to evaluate women complaining of chest pain, and even may reduce the number of women undergoing repeated coronary angiography procedures.

Always consult your physician for more information.

Online Resources

American Heart Association

Centers for Disease Control and Prevention (CDC)

Everyday Choices, AHA, ADA, and ACS

Go Red for Women Campaign, AHA

HealthierUS.Gov

National Heart, Lung, and Blood Institute (NHLBI)

National Institutes of Health (NIH)

National Library of Medicine

US Health and Human Services

October 2004

Women With Chest Pain Gain Insight With New Test

Tests Open New Avenues

Researchers Follow Women's Experiences

Heart News Round-Up

Online Resources

Heart News Round-Up

Mechanical Pump Aids Heart
The most seriously ill congestive heart failure patients live longer and have a better quality of life if implanted with a heart pump, researchers report in Circulation: Journal of the American Heart Association.

End-stage heart failure occurs when the heart is so weak, it can no longer pump enough blood and nutrients to the body’s organs. 

Standard treatment includes lifestyle modification, and medications that strengthen the heart’s pumping ability, ease the heart’s work by relaxing blood vessels, and help the body eliminate excess fluid. 

If symptoms are life-threatening despite optimal drug treatment, a heart transplant is considered.  However, there are fewer than 2,500 hearts transplanted each year in the US, and 500,000 to 800,000 patients have advanced heart failure, according to the American Heart Association.

The left ventricular assist device (LVAD) is a newer treatment option. This mechanical pump helps maintain the pumping ability of a heart that cannot work effectively on its own. 

LVADs were originally conceived as a “bridge to transplant” - a temporary device to use while patients waited for a heart transplant. Now they are now being investigated as permanent “destination therapy” for patients ineligible for transplant instead of as a temporary measure.

“The benefit of LVAD was most dramatic in the sickest people, those who will have the worst outcome without the device," says Dr. Lynne W. Stevenson, co-director of the cardiomyopathy and heart failure program at the Brigham and Women’s Hospital in Boston. 

Lab Study Heralds the Future
Researchers are on track one day to hand cardiologists the first means ever to pinpoint plaque deposits in the arteries of patients that appear poised to cause heart attack or stroke - and without surgery, biopsy, or other invasive procedure.

Biochemist Dr. Alexei A. Bogdanov Jr. and colleagues at Massachusetts General Hospital and Harvard Medical School are using a cellular model in the lab and magnetic resonance imaging (MRI) to develop their non-invasive method.

They aim to detect and trace elevated levels of an enzyme that other research groups have linked to plaque instability and cardiac risk.

Dr. Bogdanov emphasizes much work remains before the technique could reach the clinic. However, the results were so encouraging that he presented them at the American Chemical Society meeting.

If physicians have early warning that a particular plaque is unstable, they may be able to prioritize or target their patient’s treatment to that artery, perhaps averting an attack or at least minimizing its damage.

Drug-Coated Stents Studied
The new drug-coated stents, flexible tubes designed to keep arteries open, reduce the risk of heart attacks but do not provide greater life expectancy in the months after they are implanted than traditional stents, according to a study reported in the medical journal Lancet.

Analyzing data on 11 trials that compared results in 5,000 patients who got either the traditional bare-metal stents or the drug-eluting stents, researchers at McGill University in Montreal say the newer devices reduce the risk that arteries will close up again and the occurrence of "major adverse cardiac events," such as the need to perform bypass surgery.

But the overall death rate and the incidence of heart attacks were almost identical for patients who got the coated or bare stents, the analysis found.

A stent is implanted after balloon angioplasty, a procedure that widens arteries in which blood flow is impeded by fatty deposits. Coated stents, which release drugs that help keep arteries open, were introduced about five years ago and are now widely used.

It is not surprising that the analysis found no effect on the risk of death because "major events frequently are associated with disease in other arteries that do not receive stents," said Dr. Sidney Smith, chief of cardiology at the University of North Carolina and a spokesman for the American Heart Association.

It is a "very helpful study because it demonstrates the benefits of drug-eluting stents over the short term," Dr. Smith says. "If you have a drug-eluting stent, you are less likely to go back to the hospital because of restenosis [artery blockage] or an adverse cardiac event."

Always consult your physician for more information.