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Abstract: FR-PO009

The Relationship Between Intra-Parenchymal Renal Resistive Index Variation and Renal Functional Reserve Under Physiologic and Pathologic Conditions

Session Information

Category: Acute Kidney Injury

  • 101 AKI: Epidemiology, Risk Factors, and Prevention

Authors

  • Samoni, Sara, IRRIV - San Bortolo Hospital, Vicenza, Italy
  • Villa, Gianluca, University of Florence, Florence, Italy
  • De Rosa, Silvia, IRRIV - San Bortolo Hospital, Vicenza, Italy
  • Neri, Mauro, IRRIV - San Bortolo Hospital, Vicenza, Italy
  • Husain Syed, Faeq, University Clinic Giessen and Marburg-Camps Giessen, Giessen, Germany
  • de Cal, Massimo, IRRIV - San Bortolo Hospital, Vicenza, Italy
  • Nalesso, Federico, DIMED- University of Padua, Igaly, Padova, Italy
  • Meola, Mario, Sant'Anna School of Advanced Studies, Pisa, Pisa, Italy
  • Ronco, Claudio, University of Padova, IRRIV, San Bortolo Hospital, Vicenza, Italy
Background

The assessment of renal functional reserve(RFR), which is the increase of glomerular filtration rate after a protein load, has been proposed for the risk stratification of patients undergoing potentially nephrotoxic procedures. In a previous study, we described a bedside ultrasound(BUS) test (intra-parenchymal renal resistive index variation, IRRIV test) to identify the presence of RFR. The aim of the present study is to externally validate IRRIV test in a validation cohort of healthy subjects and preliminary explore the correlation between IRRIV and RFR under pathologic conditions.

Methods

We enrolled a group of healthy subjects and a group of patients scheduled for cardiac surgery. Each underwent protein loading test and IRRIV test. It relies on a mechanical abdominal stress consisting of compressing renal vessels through an externally applied weight on the abdomen (fluid-bag 10% of subject’s body weight) which reduces blood flow and activates the autoregulation mechanism. This leads to afferent vasodilation which can be measured by a fall in RRI. Pearson and logistic regression analyses were used to assess the correlation between IRRIV and RFR in both groups.

Results

In 47 healthy subjects, Pearson correlation coefficient between RFR and IRRIV is 0.83, CI95%[0.71-0.90], p<0.01. Among these, concordance between RFR and IRRIV is described in 45 subjects (95.7%). IRRIV predicts RFR with a ROC-AUC of 0.86, CI95%[0.68-1].
In 31 cardiac surgery patients, Pearson correlation coefficient between RFR and IRRIV is 0.81, CI95%[0.63-0.90], p<0.01. Among these, concordance between RFR and IRRIV is described in 27 (87.1%) patients. IRRIV predicts RFR with a ROC-AUC of 0.80, CI95%[0.64-0.96].

Conclusion

IRRIV test is a feasible BUS test that significantly predicts the presence of RFR in healthy subjects. Correlation between IRRIV and RFR seems to be also maintained in pathologic conditions.