Survival in Southern European patients waitlisted for kidney transplant after graft failure: A competing risk analysis.

BACKGROUND: Whether patients waitlisted for a second transplant after failure of a previous kidney graft have higher mortality than transplant-näive waitlisted patients is uncertain. METHODS: We assessed the relationship between a failed transplant and mortality in 3851 adult KT candidates, listed between 1984-2012, using a competing risk analysis in the total population and in a propensity score-matched cohort. Mortality was also modeled by inverse probability weighting (IPTW) competing risk regression. RESULTS: At waitlist entry 225 (5.8%) patients had experienced transplant failure. All-cause mortality was higher in the post-graft failure group (16% vs. 11%; P = 0.033). Most deaths occurred within three years after listing. Cardiovascular disease was the leading cause of death (25.3%), followed by infections (19.3%). Multivariate competing risk regression showed that prior transplant failure was associated with a 1.5-fold increased risk of mortality (95% confidence interval [CI], 1.01-2.2). After propensity score matching (1:5), the competing risk regression model revealed a subhazard ratio (SHR) of 1.6 (95% CI, 1.01-2.5). A similar mortality risk was observed after the IPTW analysis (SHR, 1.7; 95% CI, 1.1-2.6). CONCLUSIONS: Previous transplant failure is associated with increased mortality among KT candidates after relisting. This information is important in daily clinical practice when assessing relisted patients for a retransplant.

Vascular Damage and Kidney Transplant Outcomes: An Unfriendly and Harmful Link.

Kidney transplant (KT) is the treatment of choice for most patients with chronic kidney disease, but this has a high cardiovascular mortality due to traditional and nontraditional risk factors, including vascular calcification. Inflammation could precede the appearance of artery wall lesions, leading to arteriosclerosis and clinical and subclinical atherosclerosis in these patients. Additionally, mineral metabolism disorders and activation of the renin-angiotensin system could contribute to this vascular damage. Thus, understanding the vascular lesions that occur in KT recipients and the pathogenic mechanisms involved in their development could be crucial to optimize the therapeutic management and outcomes in survival of this population. This review focuses on the following issues: (1) epidemiological data framing the problem; (2) atheromatosis in KT patients: subclinical and clinical atheromatosis, involving ischemic heart disease, congestive heart failure, stroke and peripheral vascular disease; (3) arteriosclerosis and vascular calcifications; and (4) potential pathogenic mechanisms and their therapeutic targets.

Increase in CD8+CD158a+ T Cells in Kidney Graft Blood is Associated with Better Renal Function.

BACKGROUND Studies of liver and heart transplant patients have shown a gradual reconstruction of the CD8 KIR2D+ T cell subpopulations, measured in peripheral blood (PB), associated with better graft acceptance. The kinetics of these populations in kidney transplants, however, is still poorly understood, especially given the lack of studies of blood samples from the kidney graft. MATERIAL AND METHODS Flow cytometry was used to measure CD8+CD158a/b/e T cells in 69 kidney transplant patients who had stable renal function during follow-up. Measurements were made at 3, 6, and 12 months post-transplantation in graft capillary blood extracted by fine needle aspiration puncture (FNAP) and in PB. RESULTS No progressive increase was found in the PB subpopulations. However, the CD8+CD158a+ subsets increased significantly at 12 months in the graft blood versus the PB samples (3.91±4.59 vs. 2.84±4.71; p=0.021). The ratio of the percentage of CD8+CD158a+ cells in graft blood compared to PB at 12 months was associated with better renal function in those patients with a ratio ≥3 (66.6±14.53 vs. 55.7±21.6; p=0.032). CONCLUSIONS An increased ratio of CD8+CD158a+ cells, measured by flow cytometry, between graft blood and PB was associated with improved renal function.

Peripheral Vascular Disease and Death in Southern European Kidney Transplant Candidates: A Competing Risk Modeling Approach.

BACKGROUND: The association between peripheral vascular disease (PVD) and survival among kidney transplant (KT) candidates is uncertain. METHODS: We assessed 3851 adult KT candidates from the Andalusian Registry between 1984 and 2012. Whereas 1975 patients received a KT and were censored, 1876 were on the waiting list at any time. Overall median waitlist time was 21.2 months (interquartile range, 11-37.4). We assessed the association between PVD and mortality in waitlisted patients using a multivariate Cox regression model, with a competing risk approach as a sensitivity analysis. RESULTS: Peripheral vascular disease existed in 308 KT candidates at waitlist entry. The prevalence of PVD among nondiabetic and diabetic patients was 4.5% and 25.3% (P < 0.0001). All-cause mortality was higher in candidates with PVD (45% vs 21%; P < 0.0001). Among patients on the waiting list (n = 1876) who died (n = 446; 24%), 272 (61%) died within 2 years after listing. Cumulative incidence of all-cause mortality at 2 years in patients with and without PVD was 23% and 6.4%, respectively (P < 0.0001); similar differences were observed in patients with and without diabetes. By competing risk models, PVD was associated with a 1.9-fold increased risk of mortality (95% confidence interval [95% CI], 1.4-2.5). This association was stronger in waitlisted patients without cardiac disease (subhazard ratio, 2.2; 95% CI, 1.6-3.1) versus those with cardiac disorders (subhazard ratio, 1.5; 95% CI, 0.9-2.5). No other significant interactions were observed. Similar results were seen after excluding diabetics. CONCLUSIONS: Peripheral vascular disease is a strong predictor of mortality in KT candidates. Identification of PVD at list entry may contribute to optimize targeted therapeutic interventions and help prioritize high-risk KT candidates.

Clinical assessment of mortality risk in renal transplant candidates in Spain.

BACKGROUND: Prediction of mortality in wait-listed patients for kidney transplantation (KT) has not been well elucidated. We assessed whether application of the Charlson comorbidity index (CCI) and other uremia-related comorbidities, not included in the CCI, were associated with mortality in these patients. METHODS: We included 3851 adult patients from the Andalusian Registry who were placed on the waiting list for KT during the study period (1984-2012). A total of 1975 patients received a successful KT and were censored at that point, whereas 1876 were on the waiting list at any time. Multivariate Cox proportional regression analysis and competing risk models, both of which included a propensity score for factors leading to KT, were constructed to examine death in wait-listed patients. RESULTS: Overall mortality on the waiting list was 24%, and cardiovascular disease was the leading cause of death (25%), followed by infections (19%) and malignant disorders (7%). By competing risk models, age older than 50 years (subhazard ratio [SHR] 1.4; 95% CI, 1.1-1.9), CCI score higher than 3 (SHR 2.8; 95% CI, 2.1-3.7), a central venous catheter (SHR 1.8; 95% CI, 1.4-2.2) and unemployed status (SHR 1.7; 95% CI, 1.3-2.2) at dialysis entry were significantly associated with mortality. When these factors were incorporated in a composite risk model, mortality risk increased significantly with increasing risk levels. CONCLUSION: A limited number of comorbidities, easily measurable at entry to dialysis, are associated with mortality in wait-listed patients. This simple clinical assessment may help prioritize high-risk wait-listed patients for receiving an age-matched deceased donor kidney.

Decrease in the percentage of peripheral blood CXCR3highCD4+ lymphocytes after renal transplantation.

INTRODUCTION: Previous studies suggest that infiltration into the graft of active T cells following kidney transplantation depends on the expression of chemokines and their interaction with their T-cell receptors. However, little is known about the natural history of the expression of these molecules during the early post-transplantation phase. AIM: To evaluate the percentage of CXCR3highCD4+ and CCR4highCD4+ cells, as markers of the Th1 and Th2 populations, in peripheral blood from uremic patients before transplantation and six months after maintaining an acceptable kidney graft function. MATERIAL AND METHODS: Flow cytometry was used to measure CXCR3highCD4+ and CCR4highCD4+ cells from 44 consecutive patients who received a kidney transplant at our center. Measurements were made at the time of transplantation and six months later. RESULTS: There was a significant reduction after transplantation in the CXCR3highCD4+/CCR4highCD4+ balance (10.68±20.28 vs. 2.01±3.15, p=0.001). Separate analysis of each subset showed a significant reduction after transplantation in CXCR3highCD4+ (2.37±2.75 vs. 1.49±2.66, p=0.010) but no difference in CCR4highCD4+ (0.83±1.01 vs. 1.01±1.12, p=0.812). CONCLUSION: Prior to kidney transplantation uremic patients have an immunologic activation with Th1 polarization (studied by analyzing the CXCR3highCD4+ and CCR4highCD4+ populations) that falls after transplantation. This can be monitored with the CXCR3highCD4+ lymphocyte subset. This may help understand the pathologic mechanisms intervening in immunologic dysfunction of kidney grafts.

Regression of cardiac growth in kidney transplant recipients using anti-m-TOR drugs plus RAS blockers: a controlled longitudinal study.

BACKGROUND: Left ventricular hypertrophy (LVH) is common in kidney transplant (KT) recipients. LVH is associated with a worse outcome, though m-TOR therapy may help to revert this complication. We therefore conducted a longitudinal study to assess morphological and functional echocardiographic changes after conversion from CNI to m-TOR inhibitor drugs in nondiabetic KT patients who had previously received RAS blockers during the follow-up. METHODS: We undertook a 1-year nonrandomized controlled study in 30 non-diabetic KT patients who were converted from calcineurin inhibitor (CNI) to m-TOR therapy. A control group received immunosuppressive therapy based on CNIs. Two echocardiograms were done during the follow-up. RESULTS: Nineteen patients were switched to SRL and 11 to EVL. The m-TOR group showed a significant reduction in LVMi after 1 year (from 62 ± 22 to 55 ± 20 g/m2.7; P=0.003, paired t-test). A higher proportion of patients showing LVMi reduction was observed in the m-TOR group (53.3 versus 29.3%, P=0.048) at the study end. In addition, only 56% of the m-TOR patients had LVH at the study end compared to 77% of the control group (P=0.047). A significant change from baseline in deceleration time in early diastole was observed in the m-TOR group compared with the control group (P=0.019). CONCLUSIONS: Switching from CNI to m-TOR therapy in non-diabetic KT patients may regress LVH, independently of blood pressure changes and follow-up time. This suggests a direct non-hemodynamic effect of m-TOR drugs on cardiac mass.