Background: Non-invasive biomarker for kidney allograft fibrosis is needed. Shear wave elastography is a relatively new technique to assess tissue stiffness. Graft rejection and chronic dysfunction might be associated with increased stiffness. The aim of the present work is to investigate whether measurements of shear wave are correlated with standard laboratory tests for graft function in kidney transplant recipients.

Material and Methods: We included consecutive patients with kidney transplant sent to ultrasound evaluation either clinically indicated or as part of the standard follow up in asymptomatic patients. We performed standard grey-scale and Doppler evaluation, shear wave elastography evaluation included: quality assessment, virtual touch quantification (single-point shear wave speed measurement, SP-SW) and virtual touch IQ (multi-point shear wave speed measurement, MP-SW) at three sites (upper pole, interpolar region and lower pole). All examinations were performed in an ultrasound machine ACUSON S3000 (SIEMENS, Erlangen, Germany). Laboratory tests were obtained from clinical records, including SCr, microalbuminuria, serum albumin and urinary proteins. All patiens signed informed consent.

Results: We included 50 consecutive patients. Twenty-nine (58%) were male. Mean age was 37.6 years (range 19-71). The average time of transplantation was 6.4 year (range 0-29). The persistence of abnormal SCr value was found in 32 patients. In those patients with abnormal SCr, values ​​of MP-SW elastography they were significantly higher in upper pole (3.3 vs. 2.48 m/s, p=0.011), interpolar region (3.46 vs. 2.72 m/s, p=0.014), lower pole (3.68 vs. 2.94 m/s, p=0.024) and the mean value of the 3 regions (3.48 vs. 2.71 m/s, p=0.004), but the values of SP-SW elastography were significantly higher only in the lower pole (3.1 vs. 2.67 m/s, p=0.049). In multivariated regression analysis, the mean MP-SW elastography value was the only significant variable to predict persistently abnormal SCr levels (p=0.007, 95%CI 0.06-0.38). Microalbuminuria was increased in 7 (14%) patients, urinary proteins in 14 (28%) patients, and low serum albumin in 5 (10%) patients, there was no significant difference in elastography measurements.

Conclusion: Higher MP-SW elastography values are independently associated with abnormal SCr values.

CITATION INFORMATION: Dosal-Bañuelos J, Flores-Mendoza A, Morales-Buenrostro L, Díaz-Zamudio M. Correlation of the Shear Wave Elastography with Renal Function in Kidney Transplant Recipients: A Proof of Concept Study. Am J Transplant. 2016;16 (suppl 3).

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