Abdominal aortic calcification as prognostic marker in continuous ambulatory peritoneal dialysis

Patients with chronic kidney disease (CKD) on dialysis are at high risk of cardiovascular complications and mortality. We investigated the prognostic role of presence and severity of abdominal aortic calcification (AAC) detected by a simple lateral lumbar X-ray as a risk marker in CAPD.

A prospective study was undertaken in 45 patients on CAPD (continuous ambulatory peritoneal dialysis). Lateral lumbar films of consented patients were checked for the presence of AAC at the level of L1 - L4 lumbar vertebrae. The severity of aortic calcification was graded as per Antero-Posterior Severity Score (APSS). These APSS grades were correlated with the patient's demographic, biochemical, and echocardiographic findings. The patients were followed up prospectively for one year.

45 patients formed the study group. Mean standard deviation (SD) age and body mass index (BMI) were 57.2 (11.9) years and 25.8 (4.7) kg/m², respectively. Males constituted 62% of the cohort. Average duration of dialysis was 34.3 months. Diabetic kidney disease was seen in 75%. The prevalence of AAC was 47%. AAC was positively correlated with age of patient (r = 0.378; p = 0.01). No correlation with BMI, diabetes, hypertension, dialysis vintage, serum calcium, phosphorus, and PTH was seen; whereas a trend towards negative correlation with alkaline phosphatase was seen. Mitral valve calcification had a significant association with APSS severity. Patients with severe APSS (≥ 4) had poor survival, with an average survival of 37 months (Log-rank test p = 0.026). ROC analysis showed that APSS 3 predicted 1-year mortality with a specificity of 89% and sensitivity of 62% (AUC = 0.73) (p = 0.007).

Abdominal aortic calcification was present in 47% of our CAPD patients. A simple lateral pelvic skiagram can be utilized as a cost-effective tool in prediction of All-cause mortality and cardiac valvular calcification.