Vascular age is associated with the risk of dialysis or death in chronic kidney disease.

AIM: Increased arterial stiffness is associated with progressive renal deterioration and poor clinical outcomes in patients with chronic kidney disease (CKD). Assessment of vascular age as derived from arterial stiffness parameters might be an important clinical marker of cardiovascular risks. The aim of the present study is to evaluate whether the difference (△age) between vascular age and chronological age can predict the risk of reaching dialysis or death in patients with known CKD. METHODS: This longitudinal study enrolled 94 male Chinese CKD patients, aged 40-62 years. Vascular age was calculated by brachial-ankle pulse wave velocity, and measured by an ankle-brachial index-form device. The study endpoints were the commencement of renal replacement therapy or death. RESULTS: After a stepwise multivariate analysis, △age was associated independently with increased urine protein-to-creatinine ratio (ß = 0.32; P = 0.001) and decreased baseline estimated glomerular filtration rate (ß = -0.24; P = 0.008). During a median follow-up period of 62 (interquartile range = 55-66) months, the 4-year cumulative incidence of reaching the study endpoint in patients with △age = 0 and △age > 0 year was 4.9% and 25%, respectively (log-rank test, P = 0.009). Multivariate forward Cox regression analysis identified that higher △age (hazard ratio (HR) = 1.05; P = 0.027), lower baseline estimated glomerular filtration rate (HR = 0.93; P < 0.001), and history of cardiovascular disease (HR = 5.90; P = 0.031) were independently associated with progression to commencement of dialysis or death. CONCLUSION: Thus, the assessment of the difference between vascular age and chronological age may provide an alternative method to identify CKD patients at a high risk of progression to dialysis or death.

Non-invasive assessment of kidney allograft fibrosis with shear wave elastography: A radiological-pathological correlation analysis.

OBJECTIVES: To evaluate the use of shear wave elastography in assessment of kidney allograft tubulointerstitial fibrosis. METHODS: Shear wave elastography assessment was carried out by two independent operators in kidney transplant recipients who underwent allograft biopsy for clinical indications (i.e. rising creatinine >15% or proteinuria >1 g/day). Allograft biopsies were interpreted by the same pathologist according to the 2013 Banff Classification. RESULTS: A total of 40 elastography scans were carried out (median creatinine 172.5 µmol/L [interquartile range 133.8-281.8 µmol/L]). Median tissue stiffness at the cortex (22.6 kPa [interquartile range 18.8-25.7 kPa] vs 22.3 kPa [interquartile range 19.0-26.5 kPa], P = 0.70) and medulla (15.0 kPa [interquartile range 13.7-18.0 kPa] vs 15.6 kPa [interquartile range 14.4-18.2 kPa]) showed no significant differences between the two observers. Interobserver agreement was satisfactory (intraclass correlation coefficient of the cortex 0.84, 95% CI 0.70-0.92 and intraclass correlation coefficient of the medulla 0.88, 95% CI 0.78-0.94). The areas under the receiver operating characteristic curves for detection of tubulointerstitial fibrosis were estimated to be 0.75 (95% CI 0.61-0.89), 0.85 (95% CI 0.75-0.95) and 0.65 (95% CI 0.53-0.78) for cortical, medullary tissue stiffness and serum creatinine, respectively. CONCLUSIONS: Shear wave elastography can be used as a non-invasive tool to evaluate kidney allograft fibrosis with reasonable interobserver agreement and superior test performance to serum creatinine in detecting early tubulointerstitial fibrosis.