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Background and objectives Immunosuppression in kidney transplant recipients with decreased graft function and histological vascular changes can be particularly challenging. The impact of a late rescue conversion to belatacept on kidney graft survival in this context has never been studied. Methods We report a bicentric retrospective cohort study comparing CNI to belatacept switch versus CNI continuation in 139 kidney transplant recipients with histological kidney vascular damage (cv ≥ 2, g + cpt ≤ 1, i + t ≤ 1) and low eGFR (≤ 40 mL/min/1.73 m²). Primary outcome was death censored graft survival. Results During the study follow up, 10 graft losses (14.5%) occurred in the belatacept group (n = 69) versus 26 (37.1%) in the matched CNI group (n = 70) (p = 0.005). Death-censored graft survival was significantly higher in the belatacept group (p = 0.001): at 3 years, graft survival was 84.0% in the belatacept group compared to 65.1% in the control group. Continuing CNI was an independent risk factor for graft loss (HR: 3.46; p < 0.005). The incidence of cellular rejection after the conversion was low (4.3% in both groups) and not significantly different between groups (p = 0.84). Patients switched to belatacept developed significantly less DSA de novo. Belatacept was an independent risk factor for the occurrence of opportunistic infections (HR 4.84, p < 0.005). Conclusion The replacement of CNI with belatacept in patients with decreased allograft function and vascular lesions is associated with an improvement in graft survival, and represents a valuable option in a context of organ shortage. Caution should be made about the increased risk of opportunistic infection.

Background Malignant hypertension is macrovascular and microvascular endothelial injury responsible for multiple organ damage. Considering the anatomical and functional homologies between the posterior pole of the eye and the kidney, ophthalmological explorations may inform clinicians on the mechanisms underpinning concurrent kidney injury in this condition. More specifically, we investigated whether the wall-to-lumen ratio (WLR) of retinal arterioles measured by adaptive optics ophthalmoscopy could be correlated to WLR of kidney arterioles as determined by pathology. We sought to estimate the incidence of retinal arteriole occlusion a supposedly uncommon complication of malignant hypertension Methods All patients hospitalized in our renal Intensive Care Unit for malignant hypertension between 2016 and 2019 were referred to ophthalmological examinations Results Twenty-seven patients were included. Median retinal WLR was 0.39 [0.31-0.47] and was correlated with initial systolic (r=0.56, p=0.003) and mean blood pressure (r=0.46, p=0.02) upon admission. The retinal WLR was not correlated to renal pathological findings, as assessed by juxtaglomerular WLR (r=0.38, p=0.2), ratio of glomerulosclerosis (r=-0.39, p=0.2) or tubulo-interstitial fibrosis (r=-0.45, p=0.08). Retinal WLR was not associated with neurological or cardiovascular end-organ damage. Branch retinal artery occlusion were detected in 18.5% of patients and exudative retinal detachment in 29.6% of patients, without any significant correlation with canonical signs of retinal hypertension including optic disc swelling Conclusions In the setting of malignant hypertension, we failed to demonstrate a significant relationship between WLR and other meaningful end-organ injuries. However, branch retinal artery occlusion and exudative retinal detachment may have been hitherto underestimated

Background Chronic subclinical hemolysis is frequent in patients implanted with Left Ventricular Assist Device (LVAD) and is associated with adverse outcomes. Consequences of LVADs-induced subclinical hemolysis on kidney structure and function is currently unknown. Methods Thirty-three patients implanted with a Heartmate II LVAD (Abbott, Inc, Chicago IL) were retrospectively studied. Hemolysis, Acute Kidney Injury (AKI) and the evolution of estimated Glomerular Filtration Rate were analyzed. Proximal Tubulopathy (PT) groups were defined according to proteinuria, normoglycemic glycosuria, and electrolytic disorders. The Receiver Operating Characteristic (ROC) curve was used to analyze threshold of LDH values associated with PT. Results Median LDH between PT groups were statistically different, 688 IU/L [642–703] and 356 IU/L [320–494] in the “PT” and “no PT” groups, respectively p = 0.006. To determine PT group, LDH threshold > 600 IU/L was associated with a sensitivity of 85.7% (95% CI, 42.1–99.6) and a specificity of 84.6% (95% CI, 65.1–95.6). The ROC's Area Under Curve was 0.83 (95% CI, 0.68–0.98). In the “PT” group, patients had 4.2 [2.5–5.0] AKI episodes per year of exposure, versus 1.6 [0.4–3.7] in the “no PT” group, p = 0.03. A higher occurrence of AKI was associated with subsequent development of Chronic Kidney Disease (CKD) (p = 0.02) and death (p = 0.05). Conclusions LVADs-induced subclinical hemolysis is associated with proximal tubular functional alterations, which in turn contribute to the occurrence of AKI and subsequent CKD. Owing to renal toxicity of hemolysis, measures to reduce subclinical hemolysis intensity as canula position or pump parameters should be systematically considered, as well as specific nephroprotective therapies.