Calcification of different cardiac structures shown by cardiac CT: how important are lipids?

Abstract Background The relationship between dyslipidemia and atherosclerotic plaque as a risk factor for coronary artery disease is well-established. However, the involvement of lipids in the development of valve and aortic calcification beyond coronary disease is yet to be understood. Objective To evaluate the involvement of lipids in the calcification of various cardiac structures as measured by cardiac CT. Methods In this single-center study, we analyzed data from 316 consecutive patients who underwent cardiac CT scans between January 2018 and December 2019. Patients with poor imaging quality, constrictive pericarditis, prosthetic valves and/or devices were excluded. The calcium score of various cardiac structures, including coronary arteries (CA), mitral valve (MV), aortic valve (AoV), ascending aorta (AAo), and aortic arch (AAc), was calculated using the Agatston method from non-contrast ECG-gated CT. These scores were then combined to derive the valvular (VA=MV+AoV), total cardiac (TC=CA+VA), total vascular (TV=AAo+AAc), and total cardiovascular (TCV=TC+TV) calcium scores. We then collected data regarding lipid values (total cholesterol, LDL and HDL cholesterol and triglycerides). Results 275 CT scans were suitable for analysis, 142 were male (52%), with a mean age of 60±12 years (range 26–93 years). A total of 183 (66.7%) patients presented calcification in at least one location. Patients with calcification on any of the prespecified locations had higher prevalence of hypertension, dyslipidemia and type 2 diabetes mellitus (DM) than those without any calcium (p<0.05). The best regression models (using backwards conditional input method) showed that age was a significant predictor of calcification in all locations (and combinations of locations, p<0.05 for all) and HDL cholesterol was a part of these models across all calcifications types, being significant for TC score (p=0.010) and TCV score (p=0.024, see Figure). Patients above the fourth quartile (Q4) of TCV had significantly lower HDL cholesterol levels (47±12 vs 53±16mg/dL, p=0.007). Of note, total cholesterol, LDL cholesterol and triglycerides were not significant predictors of calcification in any location. Conclusion Calcification across the cardiovascular system is consistently associated with low HDL cholesterol levels, which extends beyond the traditional association with coronary disease. The calcification effect of HDL is found to be more significant than other lipids, however, the specific contribution of HDL subtypes is not yet fully understood.