Department of Nephrology, Monash Medical Centre, 246 Clayton Road, Clayton, Vic 3168, Australia.
Nephrology (Carlton). 2010 Aug;15(5):575-83. doi: 10.1111/j.1440-1797.2010.01288.x.
Vascular calcification (VC) is a major contributor to increased cardiovascular (CV) disease in chronic kidney disease (CKD) and an independent predictor of mortality. VC is inversely correlated with bone mineral density (BMD). Screening for VC may be useful to determine those at greater CV risk and dual-energy X-ray absorptiometry (DXA) may have a dual role in providing VC measurement as well as BMD.
We report cross-sectional data on 44 patients with CKD stages 3-4 and aim to determine and validate measurement of VC using DXA. Patients had computed tomography (CT) of abdominal aorta and DXA of lateral lumbar spine, to determine both aortic VC and BMD. Semi-quantitative measurement of VC from DXA was determined (blinded) using previously validated 8- and 24-point scales, and compared with VC from CT. BMD determination from L2 to L4 vertebrae on CT was compared with DXA-reported BMD.
Patients 66% male, 57% diabetic, had mean age 63.4 years and mean estimated glomerular filtration rate 31.4 +/- 12 mL/min. Aortic VC was present in 95% on CT, mean 564.9 +/- 304 Hounsfield units (HU). Aortic VC was seen in 68% on lateral DXA, mean scores 5.1 +/- 5.9 and 1.9 +/- 1.9 using 24- and 8-point scales, respectively. Strong correlation of VC measurement was present between CT and DXA (r 0.52, P < 0.001). For DXA VC 24-point score, intraclass correlations for intra-rater and inter-rater agreement were 0.91 and 0.64, respectively (8-point scale, intraclass correlations 0.90 and 0.69). Vertebral BMD measured by CT (mean 469.3 HU L2-4) also significantly correlated with lateral DXA-reported BMD (mean spine T-score -0.67 +/- 1.6) (r 0.56, P < 0.001).
Despite limitations in CKD, DXA may be useful as lateral DXA images provide concurrent assessment of aortic calcification as well as lumbar spine BMD, both correlating significantly with CT measurements. Lateral DXA may provide VC screening to determine patients at greater CV risk although more studies are needed to evaluate their potential role.
血管钙化（VC）是慢性肾脏病（CKD）中心血管疾病（CV）风险增加的主要原因，也是死亡率的独立预测因子。VC 与骨矿物质密度（BMD）呈负相关。筛查 VC 可能有助于确定那些 CV 风险更高的患者，双能 X 射线吸收法（DXA）在提供 VC 测量和 BMD 方面可能具有双重作用。
我们报告了 44 名 CKD 3-4 期患者的横断面数据，旨在确定并验证使用 DXA 测量 VC。患者进行了腹部主动脉计算机断层扫描（CT）和侧位腰椎 DXA，以确定主动脉 VC 和 BMD。使用先前验证的 8 点和 24 点量表对 DXA 测量的 VC 进行半定量测量（盲法），并与 CT 进行比较。将 CT 上 L2 到 L4 椎体的 BMD 测定与 DXA 报告的 BMD 进行比较。
患者中 66%为男性，57%为糖尿病患者，平均年龄为 63.4 岁，平均估计肾小球滤过率为 31.4 +/- 12 mL/min。95%的患者在 CT 上存在主动脉 VC，平均 564.9 +/- 304 亨氏单位（HU）。68%的患者在侧位 DXA 上可见主动脉 VC，分别使用 24 点和 8 点量表时，平均得分分别为 5.1 +/- 5.9 和 1.9 +/- 1.9。CT 和 DXA 之间存在 VC 测量的强相关性（r=0.52，P<0.001）。对于 DXA VC 24 点评分，内部评分者和外部评分者的组内相关系数分别为 0.91 和 0.64（8 点评分，组内相关系数分别为 0.90 和 0.69）。通过 CT 测量的腰椎 BMD（平均 L2-4 椎体 469.3 HU）也与侧位 DXA 报告的 BMD 显著相关（平均脊柱 T 评分-0.67 +/- 1.6）（r=0.56，P<0.001）。
尽管 CKD 存在局限性，但 DXA 可能有用，因为侧位 DXA 图像可同时评估主动脉钙化和腰椎 BMD，两者均与 CT 测量显著相关。尽管需要更多的研究来评估其潜在作用，但侧位 DXA 可能提供 VC 筛查，以确定那些 CV 风险更高的患者。
