Blood protein may be important predictor of future cardiovascular attack

02/09/04

Serum amyloid alpha link to heart disease perhaps stronger than that

PITTSBURGH, Feb. 16 – A blood protein called serum amyloid alpha (SAA) may be an important predictor of future cardiovascular attack, according to research from the multi-center Women's Ischemia Syndrome Evaluation (WISE) Study. The study – the first to find a strong relationship between SAA, which is made in response to inflammation, and coronary artery disease in women – is being published in the Feb. 17 edition of Circulation, the journal of the American Heart Association.

"Some doctors are now adding C-reactive protein (CRP) to patient lipid profiles because of past study findings that high levels of CRP are predictive of heart attack and other cardiovascular events such as stroke," said B. Delia Johnson, Ph.D., epidemiology faculty research associate at the University of Pittsburgh's Graduate School of Public Health and the study's first author. "Elevated levels of SAA also appear to be highly associated with a risk of future heart attack or stroke, but key differences in the ways CRP and SAA behave may mean that SAA also has an important predictive value for adverse cardiac events, especially in the short term."

The study included 705 women who had been referred to specialists for angiography for suspected coronary artery blockage. Participants had blood tests for SAA and CRP levels as well as a thorough angiographic assessment and were followed for three years.

"Both SAA and CRP levels were associated with a broad range of risk factors for heart disease," said Dr. Johnson. "After adjusting for other risk factors, we found that SAA levels were independently associated with active disease and also highly predictive of short-term future adverse cardiovascular events."

SAA and CRP are in a family of blood proteins that are manufactured in response to inflammation or infection. They seek out and repair tissue damage and help to protect against permanent injury.

Study results are consistent with current scientific thinking that inflammation plays an important role in the development of heart disease. But what makes the finding significant is that while CRP tends to indicate a more global reaction to systemic inflammation, SAA appears to respond more to active heart disease.

"Smoking, hormone usage and even some psychological stress are related to elevated CRP but not SAA," Dr. Johnson continued. "On the other hand, women with coronary artery disease tend to have elevated SAA but not CRP."

In the study group, results indicate that every one-milligram-per-liter of blood increase in SAA corresponded to an increase in the three-year risk for a cardiovascular event of more than 3 percent.

"Furthermore, this relationship with cardiovascular events was true whether a woman actually had obstructed coronary arteries or not," said Dr. Johnson. "More research – particularly clinical trials to discover appropriate anti-inflammatory regimens, for example – is desperately needed," she continued.

The study was funded by the National Heart, Lung and Blood Institute (NHLBI) and by grants from the Gustavus and Louis Pfeiffer Research Foundation and QMED Inc., both in New Jersey; the Women's Guild of Cedars Sinai Medical Center, Los Angeles; the Ladies Hospital Aid Society of Western Pennsylvania, Pittsburgh; and the Veterans Affairs Medical Research Service.

Source: Eurekalert & others

Last reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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