EP218: Update on Cardiac CT

Welcome to my podcast. I am Doctor Warrick Bishop, and I want to help you to live as well as possible for as long as possible. I’m a practising cardiologist, best-selling author, keynote speaker, and the creator of The Healthy Heart Network. I have over 20 years as a specialist cardiologist and a private practice of over 10,000 patients. Episode Summary Dr. Warwick Bishop, a practicing cardiologist and education advocate, discusses recent research updates on cardiac CT imaging in this episode. He examines two major studies—the Swedish SCAPIS study and a Korean exercise study—that validate his long-held observations about coronary artery disease screening and the role of calcium scoring in cardiac assessment. The episode explores how CT imaging technology can better risk-stratify patients and clarify the complex relationship between calcium deposits, plaque formation, and cardiovascular health. Key Takeaways: The SCAPIS study of over 25,000 people aged 50-64 found that approximately 40% of the population has coronary plaque, which aligns with the prevalence of coronary disease as a major cause of death. Men have nearly twice as much plaque as women, with approximately a 10-year delay in plaque accumulation between genders, suggesting optimal screening ages of 50 for men and 60 for women. A zero calcium score is an excellent gatekeeper for low risk; only 5.5% of zero-score patients had any plaque on contrast imaging, and less than 0.4% had significant stenosis. Calcium scores above 400 correlated with approximately 40% of cases showing significant arterial narrowing, warranting detailed imaging to understand plaque composition. The Korean study paradoxically found that exercise is associated with higher calcium scores and faster calcium progression, despite exercise reducing coronary event rates. Calcium serves dual purposes: it indicates both plaque formation/deposition and plaque stabilization, making interpretation complex without additional contrast imaging. Injecting contrast during CT coronary angiography is essential to differentiate between stabilized calcified plaque and dangerous fatty, unstable plaque in high-risk patients. Two patients with identical calcium scores can have vastly different risk profiles depending on the composition of their plaque, highlighting why calcium alone is insufficient for risk assessment. Risk enhancers like family history of premature coronary disease, elevated triglycerides, or prediabetes should prompt earlier screening than standard age guidelines.