Study On The Relationship Between Renal Artery Resistance Index And Renal Function In Patients With Thrombotic Microvascular Disease

ObjectiveTo explore the correlations between renal resistive index(RRI) and renal function in patients with thrombotic microangiopathy (TMA) and provide the clinical basis of predictable diagnosis and treatment in patients with acute kidney injury (AKI)MethodsPatients diagnosed with thrombotic microangiopathy admitted to department of emergency of Peking Union Medical College Hospital between August 1st,2014 and March 31th,2015 were studied. Intrarenal arteries resistive index in right kidney was detected in all case on admission by color Doppler flow image, and the serum creatinine (SCR), glomerular filtration rate (GFR) were measured at the same time. According to the diagnostic criteria of the guidelines of Kidney Disease:Improving Global Outcomes 2012 (KDIGO-AKI 2012), patients were divided into non-AKI group and AKI group. RRI and renal index were compared in two groups and the correlation between RRI and SCR also between RRI and GFR was assessed. RRI? SCR and GFR were measured at the severe stage of kidney injury again and these index were marked as RRI*/SCRmax and GFRmin.ΔRRI (RRI*-RRI)、ΔSCR (SCRmax-SCR) and ΔGFR (GFR-GFRmin) were calculated.According to the stage classification of the KDIGO-AKI 2012, patients diagnosed with AKI during their hospitalization were divided into KDIGO-1 group (n=10)、KDIGO-2 group (n=10) or KDIGO-3 group (n=16). ΔRRI、ASCR and ΔGFR were compared in three groups and the correlation between ΔRRI and ΔSCR also between ΔRRI and ΔGFR was assessed.ResultUsing RRI>0.7 as the diagnosed index for AKI,the sensitivity was 92.3% and the specificity was 80.1%. RRI was positively correlated with SCR (P=0.000) and negatively correlated with GFR (P=0.000) in all patients at the time of admission and the most severe stage of kidney injury. While there was a significant difference in the RRI* among KDIGO-1,KDIGO-2and KDIGO-3 groups (P=0.001), the ΔRRI had no significant difference.Δ RRI was not correlated with Δ GFR or Δ SCR.ConclusionRRI contributes to the diagnosis of AKI and the evaluation of renal function in patients with TMA,but it is not helpful to reflect the trends of renal injury especially for the critically ill patients.