The interscan variation of CT coronary artery calcification score: analysis of the Calcium Acetate Renagel Comparison (CARE)-2 study.
OBJECTIVE
In the Calcium Acetate Renagel Evaluation (CARE)-2 study, the effects of calcium acetate plus atorvastatin (Lipitor) on the progression of coronary artery calcifications (CACs) are evaluated versus those of Renagel, monitored using dual electron beam tomography (EBT) scans (two scans at study initiation and two at follow up). The aim of this study is to estimate the interscan variation for the Agatston score and for the volume score determined in patients with end-stage renal disease (ESRD) in the CARE-2 study.


METHODS
CAC score and volume were measured at study initiation in 463 ESRD subjects (mean age: 59.4 +/- 12.5 years, 48.3% female). All patients underwent dual scanning using an EBT, as first scan of two needed to measure the progression of CAC when treated with sevelamer (Renagel) compared with calcium acetate with or without atorvastatin. All scans in all participants were completed by using an EBT system (GE Imatron, South San Francisco, CA). Interscan variability was defined by the following formula: abs (scan A - scan B) / (0.5 x scan A + 0.5 x scan B) x 100%, where A and B denote the first and second scan, respectively, of the dual scan procedure performed before treatment. We evaluated the reproducibility of the cutpoints commonly used for calcium scores clinically, namely 1-30, 31-100, 101-400, and >400.


RESULTS
The CAC interscan variability was 11.8% using the Agatston score and 10.3% using the volume score. The reproducibility was then assessed using cutpoints 1-30, 31-100, 101-400, and >400. Agatston score variability for the four subgroups was 61.3%, 23%, 16.1%, and 8.2%, respectively (mean variability, 11.8%). Volume score variability was 60.0%, 14.4%, 14.6%, and 7.7%, respectively (mean variability, 10.3%). The correlation coefficient for scan A to scan B goes up significantly with increasing calcium scores and reaches 0.99 for scores greater than 400 (P < .0001).


CONCLUSIONS
Interscan variability was sufficiently small for patients with calcium scores greater than 30. Our study thus demonstrates a sufficient reproducibility of the calcium score using EBT. This score allows for accurate serial assessment of these patients and for comparing different therapies.
Budoff
Matthew J
MJ
Los Angeles Biomedical Research Institute at Harbor UCLA, Torrance, CA 90502, USA. Budoff@ucla.edu
Kessler
Paul
P
Gao
Yan L
YL
Qunibi
Wajeh
W
Moustafa
Moustafa
M
Mao
Song S
SS
D000085:Acetates / Q000627:therapeutic use; D000069059:Atorvastatin; D002114:Calcinosis / Q000000981:diagnostic imaging*; D017610:Calcium Compounds / Q000627:therapeutic use; D002614:Chelating Agents / Q000627:therapeutic use; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000188:drug therapy / Q000209:etiology; D018450:Disease Progression; D004359:Drug Therapy, Combination; D005260:Female; D006538:Heptanoic Acids / Q000627:therapeutic use; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use; D007676:Kidney Failure, Chronic / Q000150:complications; D008297:Male; D008875:Middle Aged; D011073:Polyamines / Q000627:therapeutic use; D011446:Prospective Studies; D011758:Pyrroles / Q000627:therapeutic use; D015203:Reproducibility of Results; D000069603:Sevelamer; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
D000085:Acetates; D017610:Calcium Compounds; D002614:Chelating Agents; D006538:Heptanoic Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D011073:Polyamines; D011758:Pyrroles; D000069603:Sevelamer; D000069059:Atorvastatin; C120662:calcium acetate