| AP National Lipoprotein Ups Heart Attack Risk
by TROY GOODMAN
DALLAS (AP) -- Cardiac patients with high levels of a little-known form of ''bad'' cholesterol in their blood are 70 percent more likely to have a heart attack than those with lower
concentrations, according to a study released Monday. The obscure cholesterol particle -- called lipoprotein(a) -- is
especially insidious because it's difficult for doctors to measure reliably and because its levels have little to do with the
better-known form of ''bad'' cholesterol, called LDL.
The elevated Lp(a) levels also have little to do with more
conventional heart disease risk factors such as smoking, high blood
pressure and poor diet. It also cannot be directly linked to high
cholesterol, or the kind whose levels can be altered through diet
or drugs, said lead researcher Dr. John Danesh, of Oxford
University in England. ''This study suggests there is a clear association between Lp(a)
and an increased risk of heart disease,'' said Danesh, who pointed
out that more than a decade worth of research previously failed to
link Lp(a) to increased risk of heart disease in the general
population. The Oxford findings were published in Monday's edition of
Circulation, a journal of the American Heart Association.
Researchers gathered data used in the study from 27 different
studies tracking more than 5,200 people who had heart disease or
survived a heart attack. The average age of the people involved in
the study was 50, Danesh said. The number of heart attacks suffered by individuals with the
highest Lp(a) concentrations was compared with the number of heart
attacks among those with the lowest Lp(a) readings. During a decade
of follow-up, the highest group had 70 percent more heart attacks
than the low-level Lp(a) study subjects. ''The message here is physicians and cardiologists should be
aware and it would be useful to know the Lp(a) levels in
patients,'' said Dr. Angelo Scanu, director of the Lipid Clinic at
the University of California, who was not involved in the Oxford
study. Lp(a) was first pinpointed in the blood some 40 years ago, but
doctors don't normally screen for this lipoprotein because no standardized
screening exists and because even when the Lp(a) is
known, very little can now be done to modify it. Unlike other kinds
of cholesterol, Lp(a) in the blood is 95 percent determined by
genes, so drugs and changes in diet have little effect on it, Danesh said.
Lp(a)'s exact role in the blood also is unknown, Scanu said, although researchers
do know it's a fat-carrying particle that
includes a protein that mimics the body's natural clot-busting
properties. Also, doctors know that blacks have two to three times the rate
of elevated Lp(a) compared with whites, yet they do not have double
to triple the prevalence of heart disease, Scanu said.
''Some people don't even view it as a risk factor,'' he said of
elevated Lp(a) levels. ''But it definitely is.'' AP-NY-09-04-00 1627EDT |