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AB0622 Renal resistive index (RRI): proposal for age-adjusted cut-off values in systemic sclerosis patients
  1. C Bruni1,
  2. V Maestripieri2,
  3. G Tesei1,
  4. M Chiostri3,
  5. C Sambalino3,
  6. S Guiducci1,
  7. S Bellando-Randone1,
  8. M Boddi3,
  9. M Matucci-Cerinic1
  1. 1Department of Experimental and Clinical Medicine, Division of Rheumatology
  2. 2Department of Internal Medicine, Division of Medicine for Care Complexity III, University of Florence
  3. 3Department of Heart and Vessels, Division of Cardiology I, Azienda Ospedaliera Universitaria Careggi, Firenze, Italy

Abstract

Background Renal resistive index (RRI) by Doppler ultrasound, reflects changes in both renal vascular and tubular-interstitial compartments and systemic vascular compliance related to physiological (age) and pathological conditions among which hypertension, diabetes mellitus, hyperuricaemia, dyslipidaemia and chronic kidney disease play a major role [1]. Because of the age-related changes in RRI reported in literature [2,3] the use of a 0.70 cut-off to detect renal damage, as proposed [4], was questioned: renal injury in younger decades (<60yrs) may occur also for RRI value <0.70 and be underestimated. In systemic sclerosis (SSc), RRI was previously correlated with disease duration, glomerular filtration rate and nailfold-videocapillaroscopy pattern [5–7], although tested on small samples and not investigating the possible confounding role of age-related RRI values.

Objectives to describe RRI in a larger scleroderma population and to test both the fixed 0.70 RRI cut-off and age-adjusted cut-offs in reflecting renal and other disease-related organ damage.

Methods SSc patients attending classified according to ACR/EULAR 2013 criteria were enrolled. Data on renal arteries Doppler ultrasound (RRI), autoantibodies status and biochemical tests for renal function/damage, subset and extent of skin fibrosis, instrumental assessment for internal organ involvement were collected and analysed as appropriate with SPSS vers 20.0. Considering that age-adjusted mean values were higher in the SSc population compared to literature values for the general population, we created SSc-specific age-adjusted pathologic cut-offs dividing our SSc population in quartiles and considering RRI values above the 75th percentile as pathologic (Table 1).

Results 190 SSc patients (age 56.3±15.0 years, disease duration 6±8,20 men) were eligible for the study. In the SSc population significant positive correlations between RRI and age, as well as significant associations between RRI and above mentioned general population comorbidities [1], were confirmed. When considering absolute value of RRI, the 0.70 pathologic cut-off and age-adjusted cut-offs validated in the general population [1], only renal function, systolic PAP, DLCO and late nailfold scleroderma pattern were associated with RRI (Figure 1). Pathologic RRI identified according to age cut-offs could not detect early renal damage, but was significantly associated with various fibrotic [interstitial lung disease (p=0.015), tendon friction rubs (p=0.032), skin fibrosis vs no skin involvement (p<0.001), higher mRSS (p=0.001)] and vasculopathic manifestations [late scleroderma pattern (p=0.002) and digital ulcers (p=0.006)] of the disease (Figure 1).

Conclusions in clinical practice, different age-related or non-related RRI cut-offs must be used when looking for renal or extrarenal SSc-induced damages.

References

  1. Boddi, Intern Emerg Med 2015;2)Boddi, Am J Hypertens 1996;3)Ponte, Hypertension 2014;4)Platt, Am J Roentgenol 1989;5)Rivolta,Arthritis Rheum 1996;6)Rosato, Seminar ARthritis Rheum 2012;7)Rosato, Arthritis Care Res 2014.

References

Disclosure of Interest None declared

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