Presentation: The Prognostic Value of Renal Biopsy in Scleroderma Renal Crisis (2007)

3 The Prognostic Value of Renal Biopsy in Scleroderma Renal Crisis

Purpose - To review outcomes and prognostic factors in scleroderma renal crisis (SRC) renal biopsy material.
Methods: Cases of SRC from 1990-2005 were ascertained from databases. Patients with new onset hypertension (>150/85) and renal impairment (GFR decrement by >30%) were included. Patients with renal biopsies (RBx) showing other diagnoses were excluded. Renal outcome was assessed by patients need for dialysis, and by calculated GFR (MDRD method). Analysis of renal biopsies was performed by one of the authors blinded to the outcomes. Parts of cortex with chronic damage were outlined on digital images, their area was measured by image analysis, and the total was expressed as a percentage of the cortical area as the index of chronic damage (ICD)1. Acute vascular changes (AVC) were defined as either or both of mucoid intimal thickening in interlobular arteries and fibrinoid necrosis in arterioles. Chronic vascular changes (CVC) were chronic intimal thickening in arteries and hyalinosis in arterioles.
Results: 110 cases were identified ( 3.8% of patients under follow up). 38 (35%) did not require any renal support acutely (no dialysis ND). 24 (23%) required dialysis and subsequently recovered sufficient renal function to discontinue dialysis (dialysis recovery DR). 44 (42%) required dialysis and did not recover (dialysis no recovery DNR). 58 of these cases had RBx.
The median ICD was 32% (IQR 16-51%). The ICD did not correlate with age or duration of scleroderma at SRC. The mean index was higher in the ND group compared with DR and DNR (44% vs. 26% and 31%, ANOVA p<0.05).
AVC were present in 36 biopsies, and CVC only in 16 (6 biopsies contained no assessable blood vessels). AVC correlated with poorer renal outcome. 48% of patients with AVC required permanent dialysis, compared with 13% with chronic changes only (odds ratio 6.6, 95% CI 1.3-33, Fisher's exact test p=0.025). Patients with AVC had a lower mean ICD (29%) than those without (49%). They had similar eGFR before SRC (75ml/min and 70ml/min), but higher serum creatinine at presentation (mean 288micromol/L vs 186 micromol/L, T-test p=0.021). There was no correlation between the presence of AVC and other prognostic factors (age or blood pressure). In the ND & DR groups, the rate of renal recovery was similar for those with AVC and those without (cumulative change in eGFR at three years, +20.8ml/min and +17.1 ml/min respectively).
Conclusions: Higher ICD correlated with less need for dialysis in SRC in this cohort. Pre-existing chronic damage does not worsen SRC outcome, and may be protective, whilst acute vascular changes are associated independently with poor renal outcome.
1. Howie AJ, Ferreira MA, Adu D. Prognostic value of simple measurement of chronic damage in renal biopsy specimens. Nephrol Dial Transplant

H. Penn, Scleroderma Society, 2 Research grants.