From the Guidelines
Coronary artery calcium (CAC) scoring is a crucial tool in primary prevention of cardiovascular disease, helping to identify asymptomatic individuals at risk and guide statin therapy, whereas in secondary prevention, its utility is limited as patients with established cardiovascular disease require aggressive risk factor modification regardless of calcium score. In primary prevention, CAC scoring can reclassify risk upward or downward in individuals with intermediate predicted risk, with a score of zero indicating very low risk and minimal need for statin therapy unless other significant risk factors exist 1. The 2019 ACC/AHA guideline recommends using CAC measurement to refine risk assessment for preventive interventions, such as statin therapy, in individuals with intermediate predicted risk (≥7.5% to <20%) or select adults with borderline (5% to <7.5%) predicted risk 1. For example, scores between 1-99 suggest mild atherosclerosis, typically warranting moderate-intensity statins, while scores of 100-399 indicate moderate atherosclerosis, generally requiring moderate to high-intensity statins 1. In contrast, secondary prevention patients should receive high-intensity statins, antiplatelet therapy, blood pressure management, and lifestyle modifications, as outlined in the 2011 ACCF/AHA/SCAI guideline for percutaneous coronary intervention 1. Key aspects of secondary prevention include lipid management with statin therapy to reduce low-density lipoprotein cholesterol, blood pressure control, diabetes management, and advising patients on the need for complete smoking cessation 1. Overall, CAC scoring is a valuable tool in primary prevention, allowing for personalized risk assessment and treatment, while in secondary prevention, the focus is on aggressive risk factor modification to reduce morbidity and mortality. The use of CAC scoring in primary prevention can help identify individuals who will benefit from statin therapy, as the presence and severity of coronary artery calcium have been shown to be associated with the likelihood of benefit from statin therapy for ASCVD risk reduction 1. In real-life clinical practice, CAC scoring can be used to guide shared decision-making about statins and other preventive interventions, taking into account the individual's risk factors, medical history, and preferences. By prioritizing the use of CAC scoring in primary prevention and aggressive risk factor modification in secondary prevention, clinicians can improve patient outcomes and reduce the burden of cardiovascular disease. The evidence from the 2019 ACC/AHA guideline and other studies supports the use of CAC scoring as a decision aid in select adults to facilitate clinician-patient risk discussion and guide preventive interventions 1. In summary, CAC scoring is a valuable tool in primary prevention, while in secondary prevention, the focus is on aggressive risk factor modification, and clinicians should use the most recent and highest quality evidence to guide their decision-making.
From the Research
Primary and Secondary Prevention Strategies
The difference between primary and secondary prevention strategies based on coronary artery calcium (CAC) score can be understood by examining the following points:
- Primary prevention strategies aim to prevent the onset of coronary artery disease (CAD) in individuals without a history of CAD, using CAC scores to assess risk and guide interventions such as statins and aspirin 2.
- Secondary prevention strategies, on the other hand, target individuals with established CAD, aiming to reduce the risk of further cardiovascular events 3, 4.
CAC Score and Risk Assessment
Key findings on CAC scores and risk assessment include:
- A CAC score of 781 or higher is associated with an annualized ASCVD mortality rate equivalent to that observed in secondary prevention cohorts 3.
- Individuals with CAC scores >300 have event rates comparable to those with established ASCVD, suggesting that they may require similar intensity of preventive approaches 4.
- CAC scores can be used to identify individuals at high risk of cardiovascular events, even among those without a history of CAD 5, 2.
Implications for Prevention Strategies
The implications of CAC scores for prevention strategies are:
- Individuals with elevated CAC scores (>300) may require more aggressive management of cardiovascular risk factors, similar to those with established ASCVD 4, 6.
- CAC scores can inform the intensity of preventive approaches, with higher scores indicating a need for more intensive interventions 3, 4.
- The presence of elevated CAC scores should be clearly documented and communicated to clinicians to ensure appropriate management of cardiovascular risk factors 6.