Lateral lumbar X-ray assessment of abdominal aortic calcification in Australian haemodialysis patients

Abstract

Aim: Vascular calcification is prevalent in patients with chronic kidney disease. Abdominal aortic calcification (AAC) can be detected by X-ray, although AAC is less well documented in anatomical distribution and severity compared with coronary calcification. Using simple radiological imaging we aimed to assess AAC and determine associations in prevalent Australian haemodialysis (HD) patients.

Methods: Lateral lumbar X-ray of the abdominal aorta was used to determine AAC, which is related to the severity of calcific deposits at lumbar vertebral segments L1 to L4. Two radiologists determined AAC scores, by semi-quantitative measurement using a validated 24-point scale, on HD patients from seven satellite dialysis centres. Regression analysis was used to determine associations between AAC and patient characteristics.

Results: Lateral lumbar X-ray was obtained in 132 patients. Median age of patients was 69 years (range 29-90), 60% were male, 36% diabetic, median duration of HD 38 months (range 6-230). Calcification (AAC score ≥ 1) was present in 94.4% with mean AAC score 11.0 ± 6.4 (median 12). Independent predictors for the presence and severity of calcification were age (P = 0.03), duration of dialysis (P = 0.04) and a history of cardiovascular disease (P = 0.009). There was no significant association between AAC and the presence of diabetes or time-averaged serum markers of mineral metabolism, lipid status and C-reactive protein.

Conclusions: AAC detected by lateral lumbar X-ray is highly prevalent in our cohort of Australian HD patients and is associated with cardiovascular disease, increasing age and duration of HD. This semi-quantitative method of determining vascular calcification is widely available and inexpensive and may assist cardiovascular risk stratification.