Heart research targets enzyme

Measuring levels of a naturally occurring enzyme in blood may help physicians determine treatment for patients "in the gray area" for risk of heart disease, according to researchers at LDS Hospital.

They presented the results of their seven-year, 1,493-patient study to the American College of Cardiology scientific session in Orlando, Fla., Monday.

Their research indicates that elevated levels of the enzyme LpPLA2, shorthand for lipoprotein-associated phospholipase A2, significantly raises the risk of coronary artery disease, according to Dr. Jeffrey L. Anderson, associate chief of cardiology at LDS Hospital and the study's clinical investigator. It also predicts the long-term risk of dying from coronary artery blockages.

Detecting elevated levels of the enzyme could predict the risk even in those who have no standard risk factors for heart disease, he said.

The study used patients enrolled in the LDS Hospital Intermountain Heart Collaborative Study registry. Researchers measured levels of LpPLA2 and the better-known C-reactive protein (CRP), known to indicate inflammation in the blood vessels. All of those enrolled had heart angioplasty to diagnose possible coronary artery disease, then the angiogram results were compared to their LpPLA2 enzyme and CRP levels to see if the latter two factors indicated the presence of heart disease. They were subsequently followed for nearly seven years to see if those LpPLA2 and CRP levels predicted future cardiovascular problems, such as heart attacks, stroke and death from blockages in the coronary arteries.

Anderson said the results indicate particular potential benefit for those who have a moderate level of risk for heart disease, based on traditional risk factors.

It's clear that coronary artery disease is not a passive process but an active one, Anderson said, believed to be triggered by inflammation in the blood vessels.

The inflammation leads to plaque, ruptures and clots that damage and kill. The hope is the study will provide another tool to identify those living with heart-disease-promoting inflammation before a cataclysmic event like a heart attack. It could also tell physicians whether someone who has had such an event still has the dangerous inflammation so that treatment could be tailored to prevent further damage.

While CRP indicates inflammation and is used as a predictor of coronary artery disease, elevated levels can also be a sign of other conditions such as infections, rheumatoid arthritis, even a cold, he said.