Stress echo tests shown to predict cardiac death, illness in higher-risk women

11/15/05

Saint Louis University cardiologist presents research at AHA meeting wednesday

ST. LOUIS New research from Saint Louis University School of Medicine may give doctors a way to predict life-threatening heart problems in women.

The team studied 421 diabetic women between 49 and 75 who underwent a certain type of stress test for suspected coronary disease. Investigators concluded that the test, known as dobutamine stress echocardiography, provided valuable information that could help doctors predict future fatal heart problems.

"Our research is extremely important because women in this age group are historically underdiagnosed, and by detecting problems earlier, we can help prevent heart attack or death and extend these women's lives," says Melda S. Dolan, M.D., associate professor in the division of cardiology at Saint Louis University School of Medicine.

Dolan will present two papers during the annual American Heart Association meeting in Dallas on Wednesday. Both papers explore the role of the stress tests in detecting heart disease.

Dobutamine stress echocardiography tests are ultrasound heart scans in which patients are injected with a drug that makes the heart beat faster to determine if they have abnormalities of the heart wall. No exercise is involved. Traditional echocardiography tests are performed without the aid of drugs by having patients run on a treadmill to increase their heart rate.

"Women with diabetes and other clinical risk factors, such as smoking, obesity and a family history, are more likely to have heart disease or die from it," says Dolan. "Dobutamine stress echo tests serve an important role in predicting heart attacks or cardiac death in these higher-risk women."

After two years, the team followed up with the patients and found that 23 had died from cardiac events and 54 had experienced heart attack. While history of congestive heart failure and previous heart attacks were clinical predictors in those cases, the dobutamine stress echo tests were also beneficial in predicting them, Dolan says.

"The rate at which the patients experienced cardiac death or heart attacks was higher in patients with positive stress tests for ischemia a decreased supply of blood to the heart than in those who had negative tests," Dolan says.

In a second study, Dolan and other SLU researchers studied 1,404 patients who underwent preoperative dobutamine stress echocardiography to determine if they had ischemia.

"In the medical community, it is common to believe the heart rate must be at least 85 percent of the maximal heart rate," Dolan says. "However, we found that a negative dobutamine stress test without abnormalities has a very strong negative predictive value that is, that patients test negative for ischemia whether the heart rate is maximal or not."

The implications for such results are that doctors ordering stress echocardiography can have more confidence in tests returning negative for ischemia than they had previously thought, effectively broadening the parameters normally used to rule out ischemia meaning some patients will not have to undergo additional heart scans to rule out the condition before they undergo surgery.

Co-authors of the studies are Swathy Kolli, M.D.; Michelle Bierig, RDCS; Jeannette A. St. Vrain, RDCS; Bernard Chaitman, M.D.; and Arthur Labovitz, M.D., director of the division of cardiology at Saint Louis University School of Medicine.

Source: Eurekalert & others

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