Coronary Artery Calcification and Coronary Plaque Progression

Quick Takes

  • Baseline CAC scores in symptomatic patients with suspected CAD often underestimate plaque presence and burden.
  • Baseline CAC scores identify patterns of plaque characteristics that persist over time.

Study Questions:

What is the relationship between baseline coronary artery calcium (CAC) score and baseline plaque characteristics as well as changes in plaque characteristics over time?

Methods:

This prospective multicenter registry evaluated 689 symptomatic patients with suspected coronary artery disease (CAD) undergoing serial coronary computed tomography angiography (CCTA) studies 3.5-4.0 years apart. The relationships between baseline CAC and plaque characteristics (including plaque volume, noncalcified plaque, stenosis severity) were examined, and progression of plaque was evaluated over time (including calcified vs. noncalcified plaque and obstructive [≥50%] stenoses) compared to baseline CAC findings. Multivariable models evaluated plaque progression by baseline CAC as well as risk of CAD events at a median follow-up of 10.7 years.

Results:

Increased baseline CAC scores were associated with increased total plaque volume (range 30.4-522.4 mm3, p < 0.001) and higher prevalence of obstructive CAD (1.4%-49.1%, p < 0.001). In patients with baseline CAC score <100, nonobstructive CAD was frequently present (40% for CAC score of 0 and 89% for CAC score of 1-99) and largely noncalcified. On the follow-up CCTA, patients with CAC ≥100 had greater volumetric plaque growth (p < 0.001) and new or worsening stenosis (p < 0.001). Patients with low baseline CAC scores had greater growth of noncalcified plaque, while patients with high CAC scores had greater growth of calcified plaque. Baseline CAC was positively associated with increased CAD event risk (3.3% risk for no CAC to 21.9% risk for CAC ≥400, p < 0.001).

Conclusions:

Baseline CAC scores in symptomatic patients with suspected CAD provide an incomplete assessment of coronary artery plaque and are associated with differences in baseline plaque characteristics and changes in plaque progression over time.

Perspective:

In a symptomatic cohort with suspected CAD undergoing serial CCTA, baseline CAC scores underestimated plaque presence and burden, with 40% of patients with a CAC score of 0 demonstrating nonobstructive plaque, which was largely uncalcified and associated with a low risk of adverse CAD events. Increasing baseline CAC scores are associated with a higher prevalence of obstructive CAD at baseline and on follow-up imaging, and increased proportions of calcified plaque among total plaque volume both at baseline and on follow-up. These findings suggest that patients with higher CAC scores have more advanced plaque that is more likely to be obstructive at baseline and more likely to become obstructive and calcified on follow-up imaging with associated higher risks of CAD events. These data demonstrate specific patterns of plaque characteristics associated with baseline CAC scores, which may be useful to prognosticate risk and identify the expected progression of CAD.

Clinical Topics: Cardiovascular Care Team, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Prevention, Atherosclerotic Disease (CAD/PAD), Interventions and Coronary Artery Disease, Interventions and Imaging, Angiography, Computed Tomography, Nuclear Imaging

Keywords: Atherosclerosis, Computed Tomography Angiography, Constriction, Pathologic, Coronary Angiography, Coronary Artery Disease, Coronary Stenosis, Diagnostic Imaging, Myocardial Ischemia, Plaque, Atherosclerotic, Primary Prevention, Risk


< Back to Listings