A simple blood test is transforming cardiovascular disease prevention

Approximately one in five Canadians has elevated levels of lipoprotein(a), known as Lp(a), a genetic risk factor that can significantly increase the risk of heart attack, stroke, and a common heart valve condition called aortic stenosis. Yet standard cholesterol tests do not measure it, meaning many people may be unaware of their risk.

Earlier and more effective disease prevention makes a life-saving difference. This is why Dr. George Thanassoulis, Professor of Medicine at McGill University and Director of Preventive and Genomic Cardiology at the McGill University Health Centre, has been motivated to improve the way cardiovascular risks are detected.

Early in his career, while studying the causes of aortic stenosis during a CIHR-funded fellowship at Boston University, Dr. Thanassoulis discovered a link between this condition and the gene responsible for producing Lp(a). Lp(a) carries a genetically determined form of cholesterol in the blood. High levels contribute to plaque buildup in the arteries, increasing the risk of heart attack, stroke, and aortic stenosis.

The genetic link was not just a scientific breakthrough: it created an opportunity to detect risk factors for these conditions early in life. Lp(a) levels remain relatively stable throughout a person’s life, so they only need to be measured once. This discovery also raised an important question for Dr. Thanassoulis at the time:

“Why are patients not being routinely tested for a risk factor that is largely determined by genetics and cannot be detected through standard cholesterol screening?”

Since then, Dr. Thanassoulis has been working with health care professionals, researchers, and patient partners to raise awareness about Lp(a) as an important risk factor for cardiovascular diseases. Their efforts helped shape the 2021 Canadian Cardiovascular Society Guidelines for the Management of Dyslipidemia for the Prevention of Cardiovascular Disease in Adults, which recommend one-time Lp(a) testing for all adults as part of an initial cardiovascular risk assessment.

The impact has been substantial in medical practice. Before the guideline change, many Canadians could not access Lp(a) testing—even when requested—leaving a significant portion of at-risk individuals unidentified. Today, Lp(a) testing is publicly funded and available in most provinces.

“Within five years, the number of patients screened for Lp(a) has risen from single digits to 10–12% of the patients who may have high Lp(a),” says Dr. Thanassoulis.

Access to Lp(a) screening empowers Canadians to better understand their health risk and act on it: “Patients can now learn their genetic risk through a simple blood test done once in a lifetime,” he explains.

Lp(a) test results also guide health care providers in recommending personalized prevention strategies to patients. Dr. Thanassoulis recently co-authored an expert consensus statement “from physicians, for physicians,” to help health care providers better assess and manage patients with elevated Lp(a). These strategies may include closer monitoring, lifestyle changes, and emerging Lp(a) lowering therapies.

More than a decade after his initial discovery, Dr. Thanassoulis continues to transform research and practice in this area. He is now investigating additional risk factors that influence cardiovascular disease in people with high Lp(a). Dr. Thanassoulis also continues to advocate for broader Lp(a) screening, so that more Canadians can benefit from earlier risk detection and more personalized prevention. Together, these efforts have the potential to reduce heart attacks and strokes and lessen the burden of cardiovascular disease on patients, families, and the health care system.

At a glance

Issue

Heart disease, stroke, and other cardiovascular conditions are among Canada’s most pressing health challenges, placing a significant burden on patients, their families, and caregivers. These conditions also cost the health care system and the economy billions each year. Standard cholesterol tests do not test for lipoprotein(a), a genetic risk factor.

Research

Thanks to Dr. George Thanassoulis’ discovery linking Lp(a) to aortic stenosis and other forms of heart disease, we may eventually find treatments for these conditions. Lp(a) testing allows Canadians to better understand and protect their health. The test can also help health care professionals support patients with improved monitoring and personalized prevention strategies.