Renal resistive index and shear wave elastography in assessment of kidney function after allogeneic hematopoietic cell transplantation: a pilot prospective observational study.

PURPOSE: Allogeneic hematopoietic cell transplantation (alloHCT) is a treatment for several otherwise incurable conditions, which carries a risk of numerous complications. This study evaluated the associations of ultrasound modalities - renal resistive index (rRI) and renal shear wave elastography (rSWE) - with the risk of kidney dysfunction, sepsis, and graft versus host disease (GvHD). MATERIAL AND METHODS: We enrolled 33 patients scheduled for alloHCT who underwent renal ultrasonography including rRI and rSWE at three time points: before conditioning, at discharge, and 100 days after alloHCT. The results were analyzed for correlations with demographic and laboratory data. Baseline rRI and rSWE values were compared between patients and the control group, consisting of 30 patients without hematological diseases. Patterns of fluctuations of the measurements and influencing factors were investigated. RESULTS: Baseline values of rRI and rSWE were higher in alloHCT patients than in the control group (p = 0.005 and 0.013, respectively). Baseline rRI in alloHCT recipients correlated negatively with estimated glomerular filtration rate (eGFR) after 100 days from alloHCT (r = -0.560, p = 0.0013). Neither rRI nor rSWE correlated with eGFR or calcineurin inhibitor concentrations. Discharge rSWE was significantly elevated in cases complicated by hypotension requiring vasopressor treatment (p = 0.008). No significant differences in rRI or rSWE were noted according to acute kidney injury, sepsis, or acute GvHD, but rSWE after day +100 was significantly lower in patients with chronic GvHD (p = 0.012). CONCLUSIONS: Baseline rRI and rSWE were higher in alloHCT patients than in the control group. Hypotension and chronic GvHD potentially influence rSWE. Further studies are necessary to evaluate the associations and influencing factors of this non-invasive modality.