How a little known particle can triple heart attack risk, even for young, healthy people
London researcher looks for ways to reduce elevated levels of lipoprotein(a)
It's a risk factor that even physicians know little about. A fatty particle in the blood called lipoprotein(a) that can triple the risk of heart attack or stroke at any age.
Most people don't have to be concerned about it because its levels are strongly determined by genetics. But as many as one in five North Americans have dangerously high concentrations of it in their blood.
Marlys Koschinsky, the scientific and executive director of the Robarts Research Institute in London, has been studying lipoprotein(a) – or lp(a) – for 30 years. She warns it can accelerate the development of plaque in the arteries and lead to blood clots, which can be fatal.
People under 50 living healthy lives have been among its victims. The problem, says Koschinsky, is it can be hard to detect and operates independently of other risk factors. And it can't be modified by diet or exercise.
Often, she says, people with no other traditional risk factors, such as obesity, smoking or high levels of bad cholesterol, can be laid low by elevated levels of lp(a).
No standard test
To make matters worse, Koschinsky says there is no standardized test for lp(a) at the moment and it's very difficult to measure.
But experts in the field and clinicians are now acknowledging the dangers.
"This is a risk factor that has to be taken into account when developing a fulsome risk profile for an individual, particularly (because) … it's genetically determined," says Koschinsky.
"People who have a family history, people who have had events, those are all people that really need to be targeted … and measured."
Because many doctors aren't aware of the threat posed by high levels of lp(a), Koschinsky says raising awareness of the issue is critical. She has spoken to cardiologists in London and other parts of the province "to help get it on the radar" and to encourage clinical collaborations.
She says some clinicians in London do measure lp(a) levels but not with standard lipid profile testing. "They're maybe sending it somewhere to have it measured … offline" because they suspect their patient might have it.
Turning to drugs
Because lp(a) levels can't be lowered by diet or exercise, Kochinskys says attention has to turned to drug interventions. "There is now at least one compound that's going into … clinical trials that will lower lp(a) up to 90 per cent."
She's involved with the process, working extensively with pharmaceutical companies that are interested in developing these compounds.
In the meantime, Kochinsksy says awareness is the key. "Getting clinicians to understand that it's important, why it needs to be tested, at least. And if nothing else at this point in time, it forms part of a risk profile for individuals."
At the same time, she and other scientists are encouraging clinicians to use existing data on lp(a) to more aggressively identify risk factors that can be modified.