Prognostic Factors of Renal Involvement in Systemic Sclerosis

Characterization of kidneys in patients with systemic sclerosis by multi-parametric magnetic resonance quantitative imaging

PURPOSE

To determine the usefulness of multiparametric magnetic resonance (MR) quantitative imaging in characterizing the kidneys in systemic sclerosis (SSc) patients.

MATERIAL AND METHODS

Forty-six SSc patients (47.9 ± 12.8 years, 40 females) and 22 age- and sex- matched healthy volunteers (46.1 ± 13.8 years, 20 females) were recruited and underwent renal MR imaging by acquiring blood oxygen level dependent and saturated multi-delay renal arterial spin labeling (SAMURAI) sequences. The T2* value, T1 value, renal blood flow (RBF), arterial bolus arrival time (aBAT), and tissue bolus arrival time (tBAT) of renal cortex were measured and compared among diffuse cutaneous SSc (dcSSc) and limited cutaneous SSc (lcSSc) groups and healthy controls using One-way ANOVA and analyzed by logistic regression.

RESULTS

Compared to healthy volunteers, SSc patients with normal estimated glomerular filtration rate (n = 40) had significantly lower T2* value (P = 0.026) in the left renal cortex, longer T1 value (right: P = 0.015; left: P = 0.023), lower RBF (right: P < 0.001; left: P < 0.001), and shorter tBAT (right: P < 0.001; left: P = 0.005) in both right and left renal cortex after adjusting for demographics. The dcSSc patients (n = 23) had significantly lower RBF in both right (226.7 ± 65.2 mL/100 g/min vs. 278.2 ± 73.5 mL/100 g/min, P = 0.022) and left (194.5 ± 71.5 mL/100 g/min vs. 252.7 ± 84.4 mL/100 g/min, P = 0.020) renal cortex compared to the lcSSc patients (n = 23) after adjusting for demographics, but the significance of the difference was attenuated after further adjusting for modified Rodnan skin score and digital ulcers.

CONCLUSION

Multi-parametric MR quantitative imaging, particularly multi-delay ASL perfusion imaging, is a useful technique for characterizing the kidneys and classification of SSc patients.

Renal involvement in systemic sclerosis

Systemic sclerosis is a rare autoimmune vasculopathy associated with dysregulated innate and adaptive immunity that leads to generalized systemic fibrosis. Renal involvement occurs in a significant proportion of systemic sclerosis patients, and is associated with worse outcome. Scleroderma renal crisis (SRC) is the most studied and feared renal complication described in systemic sclerosis. However, with the emergence of ACE inhibitors and better management, the mortality rate of SRC has significantly decreased. Renal disease in systemic sclerosis offers a wide array of differential diagnoses that may be challenging for the clinician. The spectrum of renal manifestations in systemic sclerosis ranges from an isolated decrease in glomerular filtration rate, increased intrarenal arterial stiffness, and isolated proteinuria due to SRC to more rare manifestations such as association with antiphospholipid antibody nephropathy and ANCA-associated vasculitis. The changes observed in the kidneys in systemic sclerosis are thought to be due to a complex interplay of various factors, including renal vasculopathy, as well as the involvement of the complement system, vasoactive mediators such as endothelin-1, autoimmunity, prothrombotic and profibrotic cytokines, among others. This literature review aims to provide an overview of the main renal manifestations in systemic sclerosis by discussing the most recent epidemiological and pathophysiological data available and the challenges for clinicians in making a diagnosis of renal disease in patients with systemic sclerosis.

Stem Cells in Kidney Ischemia: From Inflammation and Fibrosis to Renal Tissue Regeneration

Ischemic nephropathy consists of progressive renal function loss due to renal hypoxia, inflammation, microvascular rarefaction, and fibrosis. We provide a literature review focused on kidney hypoperfusion-dependent inflammation and its influence on renal tissue's ability to self-regenerate. Moreover, an overview of the advances in regenerative therapy with mesenchymal stem cell (MSC) infusion is provided. Based on our search, we can point out the following conclusions: 1. endovascular reperfusion is the gold-standard therapy for RAS, but its success mostly depends on treatment timeliness and a preserved downstream vascular bed; 2. anti-RAAS drugs, SGLT2 inhibitors, and/or anti-endothelin agents are especially recommended for patients with renal ischemia who are not eligible for endovascular reperfusion for slowing renal damage progression; 3. TGF-β, MCP-1, VEGF, and NGAL assays, along with BOLD MRI, should be extended in clinical practice and applied to a pre- and post-revascularization protocols; 4. MSC infusion appears effective in renal regeneration and could represent a revolutionary treatment for patients with fibrotic evolution of renal ischemia.

Peripheral blood IL-6 levels in systemic sclerosis patients: Correlation between IL-6 levels and clinical phenotypes

OBJECTIVE

Detect the expression of Interleukin-6 (IL-6) in the serum of patients with systemic sclerosis (SSc) and assess its association with clinical and laboratory features of the disease.

METHODS

The clinical data from 50 patients with SSc in the affiliated hospital of Xuzhou Medical University, China were retrospectively analyzed. The level of IL-6 in peripheral blood of systemic sclerosis patients was compared between the different clinical phenotypes groups. Spearman correlation test was used to analyze the correlation of the IL-6 with C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), creatinine, and cystatin C.

RESULTS

Interleukin-6 increased in the disease course ≥5 years, systemic sclerosis-Interstitial lung disease (SSc-ILD), pulmonary arterial hypertension (PAH), gastrointestinal involvement, and cardiac involvement group compared with the group with disease course <5 years, no SSc-ILD, PAH, gastrointestinal involvement, and no cardiac involvement group. The differences were statistically significant (p < 0.05). Correlation analysis showed that IL-6 in the group with disease course ≥5 years had a positive correlation with ESR (Rs = 0.438, p = 0.022) and CRP (Rs = 0.825, P < 0.001), whereas it was negatively correlated with creatinine (Rs = -0.481, p = 0.011). Nevertheless, when it came to disease course <5 years, the figures had no statistically significant difference.

CONCLUSION

Serum IL-6 in patients with systemic sclerosis is related to different clinical phenotypes. IL-6 helps to diagnose various phases of diseases, monitor severities of diseases, and predict the prognosis of patients.

Assessment of kidney involvement in systemic sclerosis: From scleroderma renal crisis to subclinical renal vasculopathy

The spectrum of kidney involvement in systemic sclerosis (SSc) includes scleroderma renal crisis, widely recognized as the most severe renal-vascular complication, but also several forms of chronic renal vasculopathy and reduced renal function are complications of scleroderma. Scleroderma renal crisis, myeloperoxidase-antineutrophil cytoplasmic antibody associated glomerulonephritis, penicillamine-associated renal disease, abnormal urinalysis, alteration of vascular endothelial markers, scleroderma associated-vasculopathy with abnormal renal resistance indices and cardiorenal syndromes type 5 were also reported in SSc patients. A frequent form of renal involvement in SSc patients is a subclinical renal vasculopathy, characterized by vascular damage and normal renal function. Indeed, asymptomatic renal changes, expressed by increase of intrarenal stiffness, are often non-progressive in SSc patients but can lead to a reduction in renal functional reserve. The purpose of this review is to provide an assessment of kidney involvement in SSc, from SRC to subclinical renal vasculopathy.

Serum and urine free light chains measurements in patients with systemic sclerosis: novel biomarkers for disease activity

Circulating free light chains (FLCs), considered biomarkers of B cell activity, are frequently elevated in patients affected by systemic inflammatory autoimmune diseases. As the systemic sclerosis (SSc) clinical course can be variable, this study is aimed at evaluating FLCs levels in affected individuals as biomarkers of disease activity. We assessed FLC levels in serum and urine of 72 SSc patients and 30 healthy controls (HC). Results were analyzed in comparison with overall clinical and laboratory findings, disease activity index (DAI) and disease severity scale (DSS). SSc patients displayed increased levels of κ and λ FLC in serum significantly higher than HC (p = 0.0001) alongside the mean values of free κ/λ ratio and κ + λ sum (p = 0.0001). SSc patients showed increased free κ in urine with a κ/λ higher than HC (p = 0.0001). SSc patients with increased κ + λ in serum showed that erythro-sedimentation rate (p = 0.034), C-reactive protein (p = 0.003), DAI (p = 0.024) and DSS (p = 0.015) were higher if compared to SSc patients with normal levels of FLC. A positive linear correlation was found between serum levels of free κ and DAI (r = 0.29, p = 0.014). In addition, SSc patients with increased free κ in urine had higher DAI (p = 0.048) than SSc patients with normal κ levels. Our results strengthen the role of serum FLC as useful biomarker in clinical practice to early diagnosis and monitor disease activity, showing for the first time that also urine FLC levels correlated with disease activity in SSc patients.

Estimated glomerular filtration rate and renal resistive index as possible predictive markers of mortality in systemic sclerosis

OBJECTIVE

Subclinical nephropathy is underestimated in systemic sclerosis (SSc). Study aim is to evaluate the role of renal resistance indices (RRI) and estimated glomerular filtration rate (eGFR) assessed by Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) as predictive markers of mortality during 10 years of follow-up in SSc patients.

METHODS

181 SSc patients (60 years, 152 females) were enrolled. At baseline, the GFR was estimated in 181 SSc patients and RRI was measured in 122 SSc patients. During a follow-up of 10 years we recorded the main complications of disease, date and causes of death.

RESULTS

eGFR shows a linear negative correlation with RRI. RRI showed a correlation with systolic pulmonary artery pressure (sPAP). Overall survival is lower in SSc patients with eGFR<60 ml/min and RRI ≥0.70 than in SSc patients with eGFR≥60 ml/min (p<0.0001) and with RRI<0.70 (p<0.01) both for mortality due to SSc and all causes. In multivariate analysis, eGFR<60 ml/min [HR 6.429, 95%CI (1.006-41.08), p<0.05] and forced vital capacity (FVC) [HR 0.954, 95%CI (0.911-1), p<0.05] are predictive markers of mortality due to SSc, while eGFR [HR 3.617, 95%CI (1.370-9.554), p<0.01], RRI [HR 0.210, 95% CI (0.068-0.649), p<0.01], age [HR 1.062, 95%CI (1.023-1.103), p<0.01], FVC [HR 0.967, 95%CI (0.946-0.989), p<0.01] and disease activity index (DAI) [HR 1.663, 95%CI (1.262-2.191), p<0.0001] are predictive markers of mortality due to all causes.

CONCLUSION

We demonstrate that eGFR is a predictive marker of mortality due to SSc and to all causes, conversely RRI is predictive marker of mortality due to all causes.

Renal dysfunction in systemic sclerosis beyond scleroderma renal crisis

Research regarding renal involvement in SSc has almost exclusively focused on scleroderma renal crisis (SRC). There are relatively limited data regarding renal impairment in SSc beyond SRC. We performed an electronic search using the key words systemic sclerosis or scleroderma combined with each of the following: renal dysfunction, kidney, glomerular filtration rate (GFR), proteinuria and hematuria. We searched for reports relevant to renal dysfunction in SSc beyond SRC. In 796 SSc patients recruited in five studies. 251 (31.5%) had GFR < 90 ml/min whereas 155(19.5%) patients had GFR < 60 ml/min. Most data indicate that the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula should be considered as the most suitable tool for assessing renal function in SSc pts, since it provides similar results to measured GFR. These data indicate that renal dysfunction in SSc in not uncommon and therefore patients with SSc should have their renal function assessed by GFR estimation on a regular basis.

ANCA-associated vasculitis overlaps with systemic sclerosis: a case report and literature review

Background

Systemic sclerosis (SSc) and anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) both affect the kidney and may cause renal failure. Treatment of AAV is dramatically different from that of SSc renal crisis (SRC). Kidney biopsy is not recommended for diagnosing SRC, but it is the only reliable diagnostic method for AAV.

Case presentation

Here, a 49-year-old male patient with diffuse SSc presented with acute renal insufficiency and detectable ANCA with myeloperoxidase-specific antibodies. A renal biopsy revealed necrotizing glomerulonephritis and was consistent with AAV. This finding confirms the existence of AAV and SSc overlap syndrome. The patient was treated with intravenous methylprednisolone, intravenous cyclophosphamide, tandem membrane plasma exchange, and hemodialysis. After treatment, his clinical symptoms remained stable, and his creatinine and C-reactive protein (CRP) levels have remained normalized as of his most recent follow-up after hospital discharge.

Conclusions

AAV can overlap with SSc; although this condition is rare, it is associated with considerable morbidity and mortality. Therefore, it is critical to recognize AAV in the setting of worsening renal function due to SSs and provide appropriate treatment. Several clinical features are suggestive of AAV rather than SRC, but renal biopsy is required for accurate diagnosis.

Estimated glomerular filtration rate is a marker of mortality in the European Scleroderma Trials and Research Group (EUSTAR) database

OBJECTIVES

Study aim was to evaluate estimated glomerular filtration rate (eGFR), its association with clinical disease and its predictive ability with mortality in systemic sclerosis (SSc) patients from the European Scleroderma Trials and Research Group (EUSTAR) database.

METHODS

SSc patients from the EUSTAR database with available items for calculation of eGFR at baseline visit and with a second follow-up visit were included. A cut-off of 60 ml/min was chosen for all SSc patients and 30 ml/min for scleroderma renal crisis (SRC). Cox regression and competing risk analysis were performed to evaluate the role of eGFR as predictive factor of mortality.

RESULTS

3650 SSc patients were included. Mean serum level of creatinine and eGFR were 0.8 mg/dl (IQR 0.6-0.9) and 86.6 ± 23.7 ml/min. The eGFR was significantly lower in patients with pulmonary hypertension. Overall survival (OS) was significantly reduced in SSc patients with eGFR <60 ml/min respect to patients with eGFR ≥ 60 ml/min [OS at five years 0.763 (CI 95%: 0.700-0.814) vs 0.903 (CI 95%: 0.883-0.919 p< 0.001)]. In multivariable analysis, OS was associate with male gender (p< 0.01), systolic pulmonary arterial pressure (sPAP) (p< 0.001) and eGFR (p< 0.001). Cumulative incidence of deaths due to SSc was associate with increased sPAP (p< 0.001) and reduced eGFR (p< 0.05). OS at five years of 53 SRC patients was not significantly different in SSc patients with eGFR > 30 ml/min or eGFR < 30 ml/min.

CONCLUSION

eGFR represents a predictive risk factor of overall survival in SSc. The eGFR is not a risk factor for death in SRC.

Progression of gastrointestinal symptoms over time in patients with systemic sclerosis

Up to 90% of patients with systemic sclerosis (SSc) develop gastrointestinal (GI) symptoms. To evaluate whether GI symptoms and quality of life in patients with SSc demonstrate longitudinal stability. Consecutive patients with SSc (n = 100) completed the validated university of California at Los Angeles scleroderma clinical trial consortium gastrointestinal tract 2.0 (GIT) instrument and completed the same instrument approximately 5 years later. Comparison was made between patients with diffuse (dcSSc) and limited (lcSSc) subtypes and duration of disease of less than or greater than 5 years. GIT scores were calculated and analyzed for differences. 37 patients with dcSSc and 63 patients with lcSSc were included. Social functioning score significantly improved over time [0.44 (0.59)-0.31 (0.47); P = 0.003]. Total GIT scores were lower in patients with diffuse [0.51 (0.41)] compared with limited [(0.72 (0.53); P = 0.029] disease at both baseline and follow-up. Social functioning improved similarly in both dcSSc and lcSSc over time (P = 0.004). GIT Total scores increased in 27% (27/100) of patients and did not change or improved in 73% (73/100). Patients with worsening GI status had significantly increased scores on all GIT subscales. A lower body-mass index at baseline was significantly associated with worsening GIT Total score (OR 1.22; 95% CI 1.07-1.39; P < 0.001). Patients with SSc generally demonstrate longitudinal stability or improvement in their GI symptoms, but a subset of patients experience worsening of GI symptoms and negative impacts on GI-related quality of life.

Secondary Membranous Nephropathy. A Narrative Review

Membranous nephropathy (MN) is a common cause of proteinuria and nephrotic syndrome all over the world. It can be subdivided into primary and secondary forms. Primary form is an autoimmune disease clinically characterized by nephrotic syndrome and slow progression. It accounts for ~70% cases of MN. In the remaining cases MN may be secondary to well-defined causes, including infections, drugs, cancer, or autoimmune diseases, such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), urticarial vasculitis, sarcoidosis, thyroiditis, Sjogren syndrome, systemic sclerosis, or ankylosing spondylitis. The clinical presentation is similar in primary and secondary MN. However, the outcome may be different, being often related to that of the original disease in secondary MN. Also, the treatment may be different, being targeted to the etiologic cause in secondary MN. Thus, the differential diagnosis between primary and secondary MN is critical and should be based not only on history and clinical features of the patient but also on immunofluorescence and electron microscopy analysis of renal biopsy as well as on the research of circulating antibodies. The identification of the pathologic events underlying a secondary MN is of paramount importance, since the eradication of the etiologic factors may be followed by remission or definitive cure of MN. In this review we report the main diseases and drugs responsible of secondary MN, the outcome and the pathogenesis of renal disease in different settings and the possible treatments.

Renal resistive index in IgA nephropathy and renal scleroderma vasculopathy

BACKGROUND

Renal Ultra-Sound (US) and Doppler US provide measurements which reflect changes in renal and systemic haemodynamic. The renal resistive index (RRI), obtained through the Doppler spectrum analysis of renal small arteries, is altered in several pathologic conditions. Glomerulonephritis cause minor RRI changes, while renal scleroderma vasculopathy (RSV) leads to significant RRI modifications. The aim of our study was to assess RRI in IgA nephropathy (IgAN) and RSV in a retrospective observational study and to investigate determinants of the RRI in these groups of patients.

METHODS

We enrolled 61 IgAN patients [23 female, median age 41 (33-58) years] and 80 SSc patients [71 female, median age 52 (43-60) years]. RRI was evaluated in all patients at the time of enrolment. Laboratory tests and clinical assessment were evaluated in all patients.

RESULTS

IgAN patients showed lower RRI values than RSV patients [0.70 (0.65-0.73) vs 0.66 (0.62-0.72), p < 0.01], while no significant difference in longitudinal length was observed. Median age was significantly lower in IgAN patients than in RSV patients [41 (33-58) vs 52 (43-60), p < 0.05] while IgAN patients showed a higher prevalence of high blood pressure than RSV patients (39.3% vs 13.8%, p < 0.01). The multiple regression analysis, weighted for age, showed that RRI inversely correlates with estimated glomerular filtration rate (β coefficient = -0.524, p < 0.0001).

CONCLUSION

Higher RRI were found in RSV patients than IgAN patients. IgAN is characterized mainly by glomerular injury, not leading to major RRI changes.

Renal Involvement in Systemic Sclerosis: An Update

BACKGROUND

Systemic sclerosis is an immune-mediated rheumatic disease characterized by vascular abnormalities, tissue fibrosis and autoimmune phenomena.

SUMMARY

Renal disease occurring in patients with systemic sclerosis may have a variable clinicopathological picture. The most specific renal condition associated with systemic sclerosis is scleroderma renal crisis, characterized by acute onset of renal failure and severe hypertension. Although the management of scleroderma renal crisis was revolutionized by the introduction of angiotensin-converting enzyme inhibitors, there is still a significant proportion of patients with poor outcomes. Therefore, research on establishing disease markers (clinical, ultrasonographical and serological) and clear diagnostic criteria, which could limit the risk of developing scleroderma renal crisis and facilitate diagnosis of this complication, is ongoing. Other forms of renal involvement in systemic sclerosis include vasculitis, an isolated reduced glomerular filtration rate in systemic sclerosis, antiphospholipid-associated nephropathy, high intrarenal arterial stiffness and proteinuria. Key Messages: Scleroderma renal crisis is the most specific and life-threatening renal presentation of systemic sclerosis, albeit with declining prevalence. In patients with scleroderma renal crisis, it is mandatory to control blood pressure early with increasing doses of angiotensin-converting enzyme inhibitors, along with other antihypertensive drugs if necessary. There is a strong association between renal involvement and patients' outcomes in systemic sclerosis; consequently, it becomes mandatory to find markers that may be used to identify patients with an especially high risk of scleroderma renal crisis.

The Renal Resistive Index: A New Biomarker for the Follow-up of Vascular Modifications in Systemic Sclerosis

Objective.

The aim of the present retrospective observational study was to evaluate the change of Renal Resistive Index (RRI) over time (ΔRRI) and under treatment in patients with systemic sclerosis (SSc) as well as to correlate these changes with disease complications.

Methods.

Two hundred thirty patients [29 male, median age 57 (IQR 48–67) yrs] were enrolled. At baseline and follow-up (3.43, IQR 2.81–4.45 yrs), we collected the following data: disease variables, nailfold videocapillaroscopy (NVC) pattern, forced vital capacity (FVC), diffusing lung capacity for carbon monoxide (DLCO), systolic pulmonary arterial pressure (sPAP), presence of interstitial lung disease, RRI, evaluation of glomerular filtration rate, and new onset of pulmonary arterial hypertension (PAH).

Results.

RRI value is high in SSc patients with digital ulcers and anticentromere antibodies, active and late NVC patterns, and limited cutaneous SSc. A significant correlation was observed between ΔRRI and ΔsPAP (R = 0.17, P = 0.02), with statistically higher ΔRRI (0.08 ± 0.02 vs 0.03 ± 0.05, P = 0.04) in patients complicated by PAH onset. No other new-onset complication was associated with ΔRRI. The receiver-operating characteristic curve analysis confirmed the predictive role of ΔRRI in development of new PAH (area under the curve 0.84, 95% CI 0.75–0.93, P = 0.02). In patients with SSc never exposed to sildenafil, ΔRRI was higher (0.04 ± 0.05) compared to both patients exposed to sildenafil during the study period (0.01 ± 0.05, P = 0.03) or in those exposed at the time of baseline evaluation (0.00 ± 0.05, P = 0.01).

Conclusion.

RRI and its variation in time are a reliable marker of SSc-related vasculopathy, both in renal and extrarenal compartments.

Late Gadolinium Enhancement in Cardiac Magnetic Resonance Imaging Is Associated with High Renal Resistive Index in Patients with Systemic Sclerosis

INTRODUCTION

Systemic sclerosis (SSc) is a chronic autoimmune disease characterized by microvascular damage and fibrosis of the skin and internal organs. The major complications are lung fibrosis, pulmonary artery hypertension, scleroderma renal crisis, and cardiac involvement.

OBJECTIVE

The aim of this study was to assess renal and cardiac involvement in asymptomatic SSc patients using renal Doppler ultrasound (RDU) and cardiac magnetic resonance (CMR).

MATERIALS AND METHODS

We enrolled 26 consecutive SSc patients (21 female) according to 2013 ACR/EULAR criteria. Biochemical analysis, clinical evaluation, RDU with intrarenal hemodynamic parameters (renal resistive index [RRI], pulsatility index [PI], systolic/diastolic [S/D] ratio), and CMR with late gadolinium enhancement (LGE) were investigated at the time of enrollment.

RESULTS

The median PI value was significantly (p = 0.007) higher in SSc patients with LGE than in SSc patients without LGE (1.37 [1.28-1.58] vs. 1.12 [1.06-1.26]). The median RRI value was significantly (p = 0.002) higher in SSc patients with LGE than in SSc patients without LGE (0.68 [0.65-0.73] vs. 0.64 [0.63-0.65]). The median S/D ratio was significantly (p = 0.02) higher in SSc patients with LGE than in SSc patients without LGE (3.12 [2.83-3.76] vs. 2.78 [2.64-2.84]).

CONCLUSIONS

Our study, although performed on a small SSc population, showed RRI and LGE as markers of vascular and fibrotic damage. Early detection of cardiorenal involvement in SSc patients without symptoms is important to avoid further complications.

Renal Parenchymal Thickness in Patients with Systemic Sclerosis Is Related to Intrarenal Hemodynamic Variables and Raynaud Renal Phenomenon

Objective.

Renal involvement in systemic sclerosis (SSc) ranges from urinary abnormalities, reduction of glomerular filtration rate, and high renal resistive index, to scleroderma renal crisis. Intrarenal resistance indices are considered markers of renal SSc-associated vasculopathy. The aim of this study is to evaluate renal morphological variables, such as renal length, parenchymal thickness, atrophy index, and renal sinus in patients with SSc and to correlate it with renal function and hemodynamic variables.

Methods.

There were 92 patients with SSc and 40 healthy controls (HC) enrolled in this study. Doppler and renal ultrasound (US) including renal length, parenchymal thickness, atrophy index, renal sinus, and intrarenal resistive index were measured in patients with SSc and HC.

Results.

Renal US showed significant differences between HC and patients with SSc. The renal length (mm; 106.7 ± 5.1 vs 102.3 ± 8.4) and renal sinus (70.7 ± 7.9 vs 65.3 ± 7.7 mm) were significantly (p = 0.001) higher in HC than patients with SSc. The parenchymal thickness was significantly (p = 0.004) higher in HC than patients with SSc (18 ± 3.1 vs 16.3 ± 2.5 mm). Pulsatility index, resistive index, and systolic/diastolic ratio were significantly (p < 0.0001) lower in HC than patients with SSc. The renal length was significantly (p = 0.004) higher in diffuse cutaneous SSc (105 ± 8.4) than in limited cutaneous SSc (99.5 ± 7.5).

Conclusion.

In SSc, kidney involvement is subclinical and is related to vascular injury, Raynaud phenomenon, and chronic hypoxia that can modify renal morphology. Serum creatinine is a poor marker of renal damage, and renal US could be a useful tool — together with Doppler — to evaluate renal involvement in a systemic and chronic disease such as SSc.