Is Coronary Artery Calcium (CAC) scoring beneficial after initiating statin (HMG-CoA reductase inhibitor) therapy?

From the Guidelines

Coronary artery calcium (CAC) scoring after starting statin therapy is generally not beneficial for clinical decision-making. Once a patient has been prescribed a statin based on their cardiovascular risk assessment, repeating CAC scoring doesn't typically change management and may lead to confusion. Statins like atorvastatin, rosuvastatin, and simvastatin can actually increase CAC scores despite reducing cardiovascular risk, as they promote calcification of existing plaques while stabilizing them and reducing overall plaque volume. This paradoxical increase in calcium score despite clinical benefit can cause unnecessary concern for patients and providers.

Key Points to Consider

• The primary value of CAC scoring is in initial risk stratification before starting therapy, particularly for patients at intermediate risk where the score may help decide whether to initiate statins 1.
• For patients already on statins, management decisions should instead be guided by clinical factors, lipid levels, and tolerance of medication rather than follow-up calcium scores.
• If monitoring of atherosclerosis is needed while on statin therapy, other imaging modalities that assess plaque characteristics beyond calcification might be more appropriate.
• Guidelines suggest that CAC scoring can be useful in deciding whether to start statin therapy in borderline-risk patients, but once statins are initiated, the focus should shift to monitoring clinical outcomes and adjusting therapy as needed 1.

Clinical Implications

• CAC scoring after starting statin therapy is not recommended as a routine practice, as it may not provide additional valuable information for clinical decision-making.
• Clinicians should rely on clinical judgment, patient preferences, and guidelines when deciding on the management of patients on statin therapy, rather than relying on repeat CAC scoring.
• The most recent and highest quality study 1 supports the use of CAC scoring for initial risk stratification, but not for monitoring after statin therapy initiation.

From the Research

CAC Scoring After Starting Statin: Beneficial or Not

• The use of coronary artery calcium (CAC) scoring in patients with diabetes has been shown to improve risk classification and prediction of atherosclerotic cardiovascular disease (ASCVD) events beyond risk scores in asymptomatic individuals with prediabetes and diabetes 2.
• CAC scoring may increase statin prescriptions and reduce ASCVD risk in patients with diabetes, potentially warranting routine CAC assessment in this population 2.
• The presence and severity of CAC can identify patients most likely to benefit from statins for the primary prevention of cardiovascular diseases 3.
• CAC scoring can reclassify risk upward or downward in approximately 50% of intermediate-risk patients to inform the risk discussion and guide shared decision making about statin therapy 4.
• Among individuals for whom trial-based evidence supports efficacy of statin therapy, CAC = 0 and CAC >100 are common and associated with low and high cardiovascular risks, respectively, which may guide shared decision making aimed at targeting evidence-based statins to those who are likely to benefit the most 5.

Key Findings

• Increased CAC is associated with major adverse cardiovascular events (MACE) and MACE or revascularization in patients with diabetes or prediabetes 2.
• CAC category is associated with greater statin initiation and high intensity statin initiation at one year post CAC scoring in patients with diabetes 2.
• The effect of statin use on MACE is significantly related to the severity of CAC, with the number needed to treat to prevent 1 initial MACE outcome over 10 years ranging from 100 (CAC 1 to 100) to 12 (CAC >100) 3.
• CAC scoring can help optimize statin allocation among individuals for whom trial-based evidence supports efficacy of statin therapy 5.

Implications for Statin Therapy

• CAC scoring can be used to guide statin use and improve risk classification in patients with diabetes and intermediate-risk patients 2, 4.
• The use of CAC scoring can help identify patients who are most likely to benefit from statin therapy and target evidence-based statins to those who are likely to benefit the most 3, 5.
• CAC scoring can be used to inform shared decision making about statin therapy and guide discussions about the potential benefits and risks of statin treatment 4, 5.