Impact of abdominal aortic calcification on long-term cardiovascular outcomes in patients with chronic kidney disease

Abstract

Background: The presence of abdominal aortic calcification (AAC) can predict cardiovascular (CV) outcomes in hemodialysis patients. However, little is known about the predictive value of AAC for CV outcomes in chronic kidney disease (CKD) patients without hemodialysis. The aim of this study was to investigate the prevalence and the predictive value of AAC in asymptomatic CKD patients.

Methods: We prospectively evaluated 347 asymptomatic CKD patients without hemodialysis [median estimated glomerular filtration rate (eGFR): 43.2 mL/min/1.73 m(2)]. A non-contrast computed tomography scan was used to determine the abdominal aortic calcification index (ACI) as a semi-quantitative measure of AAC. The patients were divided into three groups according to the tertiles of ACI.

Results: Among the subjects, AAC was found (ACI > 0) in 296 patients (86.3%), and the median ACI was 11.4%. During the median follow-up of 41.5 months, a total of 33 CV events were observed. Patients with the highest tertile of ACI had the highest risk of CV outcomes compared with the other two groups (96.5%, 93.0%, and 74.3%, respectively; p < 0.001). The Cox proportional hazard models showed that ACI was an independent predictor of CV outcomes (hazard ratio 1.36, 95% confidence interval 1.17-1.60, p < 0.001). The C-index was also significantly increased by adding eGFR and ACI values to the model along with the other conventional risk factors (0.79 versus 0.66, p = 0.043).

Conclusion: Evaluation of the AAC provides useful information for predicting adverse clinical outcomes among asymptomatic CKD patients without hemodialysis.

Keywords: Abdominal aortic calcification; Aortic calcification index; Cardiovascular outcomes; Chronic kidney disease.