How long is the warranty period for nil or low coronary artery calcium in patients new to hemodialysis?

BACKGROUND

Coronary artery calcification (CAC) is common in patients with advanced chronic kidney disease on dialysis. A sizeable proportion of patients has no or minimal CAC at the inception of dialysis, but it is unclear how long they remain free of it.

METHODS

For the purpose of this study, 36 incident hemodialysis patients were submitted to sequential chest computed tomography to quantify CAC at baseline, 6, 12, 18 and 30 months.

RESULTS

Among them, 15 had absent or minimal CAC score (CACS 0 to 30) and 21 had a CACS>30 at baseline. Overall, the median baseline CACS was 129 (interquartile range [IQR]=0-709) and it increased to 364 (IQR=8.3-1683) at study completion (182% increase). Among the 15 patients with minimal CACS, only 3 progressed and the median CACS increase was 20, as opposed to 15 of 21 patients with a baseline CACS>30 whose median progression was 431 (p<0.02). The 18 patients who had CACS progression were older (68.5 vs. 57.3 years, p=0.0081) and exhibited a poorer control of mineral metabolism (phosphorus 5.2 vs. 4.9 mg/ dL, p=0.048; corrected calcium x phosphorus product [CaxP] 49.3 vs. 46.2 mg2/dL2, p=0.001) than the patients without progression. On multivariable analysis, independent predictors of progression were baseline CACS (p=0.038) and time-averaged Cax;P (p=0.077).

CONCLUSION

These data suggest that absent or low CAC at baseline is associated with minimal progression even up to 30 months. Careful management of mineral metabolism appears to be one of the main factors that limit progression of CAC.