Aortic valve calcium as a novel risk marker for kidney function deterioration: The MESA study

Abstract

Background: Aortic valve calcium (AVC) is associated with increased risk of mortality, cardiovascular disease (CVD), non-CVD such as dementia. Traditional atherosclerotic CVD risk factors are associated with both AVC and chronic kidney disease (CKD), but whether there is an association between AVC and CKD is unknown.

Objectives: To ascertain whether AVC quantified by cardiac CT scanning is independently associated with the long-term risk of incident CKD among individuals without a previous history of CVD.

Methods: We examined 6346 Multi-Ethnic Study of Atherosclerosis (MESA) participants who underwent cardiac CT scanning at Visit 1 (2000-02) and had an eGFR of ≥ 60 mL/min/1.73 m². AVC was quantified using the Agatston method and categorized as 0, 1-99, and ≥100. Incident CKD was defined as an eGFR < 60 mL/min/1.73 m² accompanied with an at least 40 % decline in eGFR from baseline, and/or a diagnosis of CKD and indicators of end stage renal disease extracted from hospital records using the International Classification of Disease (ICD) codes. We performed Kaplan-Meier survival curve analyses along with multivariable adjusted Cox proportional hazard regression models to examine the association between AVC (categorical and log-transformed) and incident CKD.

Results: Participants had a mean age 62.2 ± 10.1 years, 53 % were women, and AVC >0 was present in 795 (12 %) participants. During a median follow-up time of 16.9 years, 982 (15 %) participants developed incident CKD. AVC examined as a continuous variable was associated with a significantly increased risk of developing CKD (per log-unit [AVC+1] HR 1.06 [95 % CI: 1.02-1.10]; p = 0.005). Kaplan-Meier models showed a higher cumulative incidence for CKD with higher AVC levels. In the multivariable adjusted Cox models, participants with AVC ≥100 had a higher risk of incident CKD, compared with the AVC=0 group (HR 1.48 [95 % CI: 1.15-1.89]; p = 0.002). The observed associations remained after further adjusting for CAC score (p = 0.024), Lp(a) (p = 0.004), and the APOE-ε4 genotype (p = 0.004).

Conclusions: In a multi-ethnic cohort of participants free of CKD at baseline, AVC was independently associated with a higher risk of incident CKD. Further work is needed to understand the multidirectional relationship between AVC, CKD, and atherosclerosis.

Keywords: Albuminuria; Aortic valve calcium; Chronic kidney disease.