Coronary spotty calcification, compared with macro calcification, is associated with a higher level of vascular inflammation and plaque vulnerability in patients with stable angina.

Background And Aims: Spotty calcification in the coronary arteries is considered to represent plaque vulnerability, whereas more advanced calcification is thought to be a feature of advanced stable plaque. However, data supporting this notion is limited. Inflammation plays a key role in atherogenesis, including the formation of early-stage calcification. We aimed to correlate spotty calcification assessed by optical coherence tomography (OCT) with vascular inflammation assessed by percutaneous coronary adipose tissue (PCAT) attenuation on coronary computed tomography angiography (CCTA) and OCT-derived plaque vulnerability.

Methods: Patients with stable angina pectoris who had both CCTA and OCT prior to coronary intervention were included. Patients were classified into two groups according to the type of calcification assessed by OCT at the target lesion: spotty calcification (maximal calcification arc <90° and length <4 mm) and advanced calcification (maximal calcification arc ≥90° or length ≥4 mm) group. Non-calcified plaques, and plaques with mixed spotty and advanced calcification were excluded.

Results: Among 355 patients, 77 had spotty calcifications and 72 had advanced calcification. The spotty calcification group showed a significantly higher level of PCAT attenuation of target vessel (-69.6 [-75.2 to -66.1] vs. -74.6 [-83.1 to -69.7 HU], p < 0.001) and a significantly higher prevalence of lipid-rich plaque (94.8 % vs. 72.2 %, p < 0.001) and macrophage (77.9 % vs. 59.7 %, p = 0.016), compared with the advanced calcification group.

Conclusions: Plaques with spotty calcification are associated with a higher level of perivascular inflammation and a higher prevalence of features of plaque vulnerability than those with advanced calcification.