Correlation of Global Cardiac Microcalcification with CHADS₂and CHADS₂-VASc Scores in Individuals At-risk for Cardiovascular Disease as Assessed by NaF-PET/CT

Objectives: CHADS₂ (scored as 1 point each for congestive heart failure, hypertension, diabetes mellitus, age ≥75 years, and 2 points for past stroke/transient ischemic attack) and CHA₂DS₂‐VASc (scored as 1 point each for congestive heart failure, hypertension, diabetes mellitus, vascular disease, age 65 to 75 years, or female sex, and 2 points each for age ≥75 years or past stroke/transient ischemic attack) scores have been previously used to predict risk of systemic thromboembolism in atrial fibrillation. There is data suggestive that these scoring systems are predictive of severity of atherosclerotic disease and major cardiovascular events regardless of arrhythmic status, with higher scores indicating greater risk. NaF is a useful PET tracer that has the ability to detect active atherosclerotic calcific activity at a molecular level. In this study, we aim to quantify global cardiac microcalcification in patients at risk for cardiovascular disease as assessed by NaF uptake on PET/CT and correlate this uptake with CHADS₂ andCHA₂DS₂‐VAScscores. We hypothesize that global cardiac microcalcification will correlate positively with CHADS₂ andCHA₂DS₂‐VAScscores.

Methods: We identified 40 patients at-risk of cardiovascular disease from the CAMONA trial (55±11.9 years, 22 females, 18 males). CHADS2 (0.75±0.19) and CHADS₂-VASc (1.8±1.25) scores were calculated for each patient based on relevant clinical parameters pertaining to each scoring system. All patients underwent PET/CT imaging 90 minutes following injection of NaF (2.2Mbq/kg). A uniform and standardized protocol was followed for acquisition of the images. CT imaging was conducted to account for attenuation correction and anatomic referencing. Analysis was performed on axial images using OsiriX MD software. The global cardiac uptake was measured by a trained physician by manually drawing regions of interest (ROIs) on each axial slice. The global cardiac average SUVmean (aSUVmean) was calculated for each individual. Linear regression models were employed for statistical analysis.

Results: The linear regression model had a positive correlation between global cardiac aSUVmean and CHADS₂ score (r=0.58, p=<0.0001). The linear regression between global cardiac aSUVmean and CHA₂DS₂‐VASc was also found to be significant (r=0.37, p=0.01).

Conclusions: Global cardiac NaF uptake on PET/CT correlated positively with both CHADS₂ and CHA₂DS₂‐VASc scores. Our data provides further evidence to support the association of these scoring systems with cardiac atherosclerotic burden.