NEW YORK (GenomeWeb) – In a new study this week, researchers have demonstrated that adding analysis of a specific type of triglyceride may improve the ability to identify individuals with a higher risk of cardiovascular disease and stroke over currently used lab tests.
Writing in the Journal of the American College of Cardiology earlier this week, the study authors reported that looking at levels of a specific lipoprotein, along with other risk factors, can pick out more individuals who will later go on to experience cardiovascular disease incidents like heart attacks and strokes.
The findings emerged from an analysis of the ongoing Atherosclerosis Risk in Communities (ARIC) study. Investigators set out to explore how adding an analysis of two specific molecules — remnant lipoprotein cholesterol (RLP-C) and low-density lipoprotein triglycerides (LDL-TG) — to an existing risk prediction tool called the Pooled Cohort Equation, might improve the ability to identify individuals in the study who later developed cardiovascular disease.
"Since triglycerides and cholesterol are carried through the bloodstream in multiple particles known as lipoproteins, our focus was to take a closer look at the levels in those particles and how they affect outcomes," study author Christie Ballantyne, professor of medicine and chief of the sections of cardiology and cardiovascular research at Baylor, said in a statement.
Overall, the study included measurements of RLP-C and LDL-TG in 9,334 men and women who did not at the time of testing have prevalent cardiovascular disease. The cohort was then followed for up to 16 years. Researchers measured the relationship between LDL-TG and RLP-C levels and the development of cardiovascular disease, as well as with genetic variants detected using whole-exome sequencing.
Based on their analysis of the two lipoproteins in the ARIC data, the authors concluded that RLP-C levels didn't add any extra information to the existing Pooled Cohort risk prediction tool. LDL-TG, however, did improve the prediction of both heart attack and stroke.
"Usually lipid measurements are not associated with risk for stroke," Baylor postdoc Anum Saeed added. "We normally don’t check these levels, but our results are showing us that this appears to be the best predictor."
According to the study authors, there have been previous efforts that analyzed a relationship between LDL-TG and cardiovascular events, which unfortunately showed no added value for the lipoprotein over other risk factors. But the size and structure of their new analysis from ARIC suggest that these latest findings may supersede earlier negative results.
From the genetic portion of the study, the investigators were also able to detect an association between RLP-C and LDL-TG levels and the presence of a known cardiovascular risk variant in the APOE gene known as APOE2 — with variant carriers showing higher RLP-C and lower LDL-TG on average.
"We already know that APOE2 is associated with lower risk of cardiovascular disease; thus the lower level of LDL-TG observed in these individuals suggests that reduced LDL-TG may play an important role in protection from cardiovascular disease," Ballantyne said in his statement.
If confirmed and validated further, the authors argued that their findings could have implications for clinical practice and associated lab testing in the cardiovascular disease space.
For one, if LDL-TG really does improve the detection of individuals who have a high risk of stroke and heart attack, adding it to the standard strategies for laboratory blood testing could help identify and intervene in more incipient cases.
The investigators also wrote that the findings could lead to new treatment possibilities, such as drugs that rapidly clear triglyceride-rich lipoproteins from the blood, thereby lowering LDL-TG levels. According to Saeed, the team's next steps will include studying how lifestyle modifications or medications affect LDL-TG levels and how that in turn impacts cardiovascular disease outcomes.