Analyses & Studies • Publications
Focus Healthcare: Personalising Heart Disease Risk Assessment Through CT Coronary Angiography
Heart disease remains a leading cause of illness and mortality in Singapore, emphasizing the critical importance of accurately assessing an individual's risk of developing a cardiovascular event. This is a common question to me in clinical practice. An individual will be referred or attend the clinic out of self-questioning, curious to evaluate their risk of having a heart attack.
Traditional risk assessment calculators incorporating age, gender, cholesterol levels, and blood pressure are familiar to all clinicians, easy to use and provide valuable insights, but they may not capture the full spectrum of risk factors that can contribute to heart disease. Given that the most successful preventative care programs have relied upon advanced imaging for direct visualization, namely mammograms, colonoscopies and CT lung scans for breast, colon and lung cancer respectively, emulation of this principle to preventing heart disease is also possible. In recent years, advances in medical imaging technology have paved the way for a more personalized approach to assessing heart disease risk using CT coronary angiography.
CT Coronary Angiography (CTCA):
CT Coronary Angiography is a non-invasive imaging technique that allows direct visualization of the coronary arteries, which supply blood to the heart muscle. This imaging modality can generate 3D images of the heart and its blood vessels, providing detailed information about the presence of coronary artery disease (CAD) and the extent of any ‘blockages’.
The principal advantage of CTCA is its ability to detect atherosclerotic disease at an early stage, even before symptoms manifest. Atherosclerosis, characterized by the buildup of cholesterol-rich plaque within the arteries, is a major risk factor for heart attacks. CTCA can identify high risk individuals and guide targeted interventions to mitigate this risk. The physical appreciation of coronary plaque represents an individual’s lifelong exposure to all known and unknown risk factors.
In the absence of known risk factors, CTCA may reveal the presence of plaque and conversely, patients with predisposing risk factors but no visible disease will avoid being prescribed unnecessary medication.
The CTCA enables your cardiologist to personalize risk assessment by assessing the total plaque burden and can risk stratify individuals based on the severity of arterial blockages. By quantifying the degree of stenosis (narrowing), treatment strategies can be tailored to each patient's specific needs. For example, individuals with significant stenosis may benefit from invasive interventions such as angioplasty or bypass surgery, whereas those with mild or moderate stenosis may focus on lifestyle modifications and medications. Furthermore, emerging science can distinguish between plaques causing similar levels of stenosis and identify characteristics with a vulnerable composition that may rupture, leading to a heart attack.
Another quantifiable parameter from CT imaging is the extent of calcification within the coronary arteries. The coronary artery calcium score has been shown to correlate with future cardiovascular events. By incorporating this information into risk assessment modelling, your cardiologist can further refine individual risk predictions and tailor preventive strategies accordingly.
CT fractional flow reserve (FFR) assessment is another valuable tool for interpreting the importance of a particular blockage. CT FFR non-invasively evaluates the hemodynamic significance of the blockage by calculating the pressure drop across it. By identifying blockages that are flow-limiting, CT FFR assessment can help prioritize treatment for patients at higher risk of an adverse event. This personalized approach to risk stratification helps optimize clinical outcomes and resource allocation by focusing on patients who stand to gain the most from intervention (Figure 1). On the other hand, patients with functionally non-significant blockages may benefit from medications only and lifestyle modifications.
Figure shows the CT-FFR of the blockage in a major coronary artery is <0.80 and therefore functionally significant:
Personalized risk assessment provided by CTCA has significant implications for preventive cardiology. By identifying individuals at high risk of developing heart disease, healthcare providers can initiate targeted interventions to reduce the likelihood of adverse cardiovascular events. This may include lifestyle modifications such as dietary changes, regular exercise, smoking cessation, and stress management, as well as evidence-informed use of medication to control risk factors such as hypertension, hyperlipidemia, and diabetes.
Being non-invasive, CTCA, calcium scoring with functional assessment by CT-FFR can help monitor the effectiveness of preventive interventions and medication over time by assessing changes in plaque burden and arterial stenosis through serial scanning. This enables your cardiologist to adjust treatment strategies as needed, track the progression of atherosclerosis in high-risk individuals and intervening when appropriate, resulting in optimized long-term outcomes.
By Dr Rohit Khurana, Senior Consultant Cardiologist, The Harley Street Heart and Vascular Centre
