title: Renal artery calcified plaque associations with subclinical renal and cardiovascular disease.
abstract: BACKGROUND
  The prognostic significance of renal artery calcified plaque (RAC) and its relationship with renal function, albuminuria, and systemic atherosclerosis are unknown.
  
  
  METHODS
  Calcified atherosclerotic plaque was measured in the renal arteries of 96 unrelated Caucasian subjects with type 2 diabetes mellitus (DM) using four-channel multidetector-row computed tomography (MDCT4). Renal artery calcium was measured as the sum of ostial and main renal artery calcium scores. Participants also underwent MDCT scanning to measure coronary artery calcium (CAC), carotid artery calcium, common iliac artery calcium, infra-renal aorta calcium, and B-mode ultrasound to measure carotid artery intima-medial thickness (IMT). Spearman's rank correlation coefficients were used to assess associations between RAC and measures of subclinical renal and cardiovascular disease. Partial correlation coefficients were computed to adjust for the potential confounding effects of age, gender, body mass index (BMI), DM duration, smoking, and serum cholesterol and triglyceride levels.
  
  
  RESULTS
  Characteristics of the study group were 54% (52/96) female with a mean +/- SD (median) age 62.8 +/- 8.4 (62.5) years, DM duration 10.6 +/- 6.3 (8.0) years, hemoglobin A1C 7.5 +/- 1.5 (7.2)%, BMI 32.1 +/- 6.3 (31.1) kg/m(2), serum creatinine concentration 1.11 +/- 0.18 (1.10) mg/dL, urine albumin:creatinine ratio (ACR) 105.3 +/- 423.1 (17.6) mg/g, modified MDRD equation glomerular filtration rate (GFR) 64.3 +/- 12.6 (63.6) mL/min, RAC 372 +/- 799 (101), CAC 1819 +/- 2594 (622), carotid artery calcium 264 +/- 451 (72), and B-mode ultrasound carotid IMT 0.70 +/- 0.12 (0.69) mm. Sixty-five percent of subjects (62/96) had detectable RAC. Renal artery calcium was significantly associated with CAC (r= 0.50, P < 0.0001), carotid artery calcium (r= 0.58, P < 0.0001), common iliac artery calcium (r= 0.45, P < 0.0001), infra-renal aorta calcium (r= 0.70, P < 0.0001), IMT (r= 0.40, P= 0.0004), diastolic blood pressure (r=-0.33, P= 0.0009), BMI (r=-0.19, P= 0.0573), and age (r= 0.54, P < 0.0001). There was no association between RAC and GFR (r=-0.15, P= 0.1637) or between RAC and urine ACR (r= 0.07, P= 0.5083).
  
  
  CONCLUSIONS
  Renal artery calcium is strongly associated with older age, diastolic blood pressure, BMI, carotid artery IMT, and coronary, carotid, common iliac artery, and infra-renal aorta calcium in Caucasians with type 2 diabetes mellitus. Renal artery calcium, similar to CAC and IMT, appears to be a useful noninvasive marker of subclinical atherosclerosis. However, RAC is not significantly associated with either GFR or albuminuria.
authors.affiliation: Department of Internal Medicine/Nephrology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157-1053, USA. bfreedma@wfubmc.edu
authors.forename: Barry I
authors.initials: BI
authors.lastname: Freedman
authors.forename: Fang-Chi
authors.initials: FC
authors.lastname: Hsu
authors.forename: Carl D
authors.initials: CD
authors.lastname: Langefeld
authors.forename: Donald W
authors.initials: DW
authors.lastname: Bowden
authors.forename: Shahriar
authors.initials: S
authors.lastname: Moossavi
authors.forename: Bonnie N
authors.initials: BN
authors.lastname: Dryman
authors.forename: J Jeffrey
authors.initials: JJ
authors.lastname: Carr
mesh_terms: D000328:Adult; D000368:Aged; D001161:Arteriosclerosis / Q000150:complications* / Q000000981:diagnostic imaging / Q000473:pathology*; D002114:Calcinosis / Q000000981:diagnostic imaging / Q000473:pathology; D002318:Cardiovascular Diseases / Q000150:complications*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000150:complications*; D008297:Male; D008875:Middle Aged; D012077:Renal Artery / Q000000981:diagnostic imaging / Q000473:pathology*; D014057:Tomography, X-Ray Computed