Céline Maréchal

Aortic Stiffness and Central Wave Reflections Predict Outcome in Renal Transplant Recipients

Although renal transplantation improves survival, cardiovascular morbidity and mortality remain significantly elevated compared with nonrenal populations. The negative impact of traditional, uremia-related, and transplantation-related risk factors in this process remains, however, largely unexplored. Surrogate markers such as aortic stiffness and central wave reflections may lead to more accurate cardiovascular risk stratification, but outcome data in renal transplant recipients are scarce. We aimed to establish the prognostic significance of these markers for fatal and nonfatal cardiovascular events in renal transplant recipients. Carotid-femoral pulse wave velocity, central augmentation pressure, and central augmentation index were measured in a cohort of 512 renal transplant recipients using the SphygmoCor system. After a mean follow-up of 5 years, 20 fatal and 75 nonfatal cardiovascular events were recorded. Using receiver operating characteristic curves, the area under the curve for predicting cardiovascular events was 0.718 (95% CI 0.659–0.776) for pulse wave velocity, 0.670 (95% CI 0.604–0.736) for central augmentation pressure, and 0.595 (95% CI 0.529–0.660) for central augmentation index. When we accounted for age, gender, and C-reactive protein in Cox-regression analysis, pulse wave velocity (hazard ratio: 1.349 per 1 SD increase; 95% CI 1.104–1.649; P=0.003) and central augmentation pressure (hazard ratio: 1.487 per 1 SD increase; 95% CI 1.219–1.814; P<0.001) remained independent predictors of outcome. Aortic stiffness and increased wave reflections are independent predictors of cardiovascular events in renal transplant recipients. As single parameter of wave reflection, central augmentation pressure was better than central augmentation index. Combined measurement of pulse wave velocity and central augmentation pressure may contribute to an accurate cardiovascular risk estimation in this heterogeneous population.

Progression of Coronary Artery Calcification and Thoracic Aorta Calcification in Kidney Transplant Recipients

BACKGROUND Vascular calcification independently predicts cardiovascular disease, the major cause of death in kidney transplant recipients (KTRs). Longitudinal studies of vascular calcification in KTRs are few and small and have short follow-up. We assessed the evolution of coronary artery (CAC) and thoracic aorta calcification and their determinants in a cohort of prevalent KTRs. STUDY DESIGN Longitudinal. SETTING & PARTICIPANTS The Agatston score of coronary arteries and thoracic aorta was measured by 16-slice spiral computed tomography in 281 KTRs. PREDICTORS Demographic, clinical, and biochemical parameters were recorded simultaneously. OUTCOMES & MEASUREMENTS The Agatston score was measured again 3.5 or more years later. RESULTS Repeated analyzable computed tomographic scans were available for 197 (70%) KTRs after 4.40 ± 0.28 years; they were not available for the rest of patients because of death (n = 40), atrial fibrillation (n = 1), other arrhythmias (n = 4), refusal (n = 35), or technical problems precluding confident calcium scoring (n = 4). CAC and aorta calcification scores increased significantly (by a median of 11% and 4% per year, respectively) during follow-up. By multivariable linear regression, higher baseline CAC score, history of cardiovascular event, use of a statin, and lower 25-hydroxyvitamin D(3) level were independent determinants of CAC progression. Independent determinants of aorta calcification progression were higher baseline aorta calcification score, higher pulse pressure, use of a statin, older age, higher serum phosphate level, use of aspirin, and male sex. Significant regression of CAC or aorta calcification was not observed in this cohort. LIMITATIONS Cohort of prevalent KTRs with potential survival bias; few patients with diabetes and nonwhites, limiting the generalizability of results. CONCLUSION In contrast to previous small short-term studies, we show that vascular calcification progression is substantial within 4 years in prevalent KTRs and is associated with several traditional and nontraditional cardiovascular risk factors, some of which are modifiable.

The relation between hypomagnesaemia and vascular stiffness in renal transplant recipients

BACKGROUND Arterial stiffness is a strong predictor of outcome. Hypomagnesaemia, by its association with arterial hypertension, endothelial dysfunction, dyslipidaemia and inflammation, might affect vascular stiffness. As hypomagnesaemia is common in renal transplant recipients (RTR), we examined its potential association with arterial stiffness. METHODS Cross-sectional analysis. Evaluation of vascular stiffness in 512 RTR from two university centres at a median of 72 months post-transplantation. Determination of carotid-femoral pulse wave velocity (PWV) (SphygmoCor). A multiple linear regression analysis was used to investigate the independent relationship between magnesium serum level and PWV with the following covariates: age, diabetes, smoking status, body mass index, blood pressure, heart rate (HR), C-reactive protein (CRP), high-density lipoprotein cholesterol, parathyroid hormone and use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers, diuretics, calcium channel blockers, statins and calcineurin inhibitors next to their drug levels. RESULTS Lower serum magnesium was independently associated with PWV (P = 0.018) in addition to age, CRP, HR, diabetes and mean arterial pressure (model R(2) = 0.45; P < 0.001). The relationship between magnesium and PWV was attenuated (P = 0.054) after adjustment for the use of sirolimus, which was associated with higher magnesium levels (P<0.001) and lower PWV (P = 0.013). In patients >55 years (median age), however (low), magnesium remained an independent predictor of PWV (P = 0.024) after accounting for the same covariates. CONCLUSIONS Serum magnesium is an independent predictor of arterial stiffness in RTR, especially in patients >55 years.

Serum fetuin-A levels are associated with vascular calcifications and predict cardiovascular events in renal transplant recipients.

BACKGROUND AND OBJECTIVES Vascular calcifications predict cardiovascular disease, the major cause of death in renal transplant recipients (RTRs). We studied the determinants of fetuin-A, a potent circulating calcification inhibitor encoded by the AHSG gene, and tested its association with vascular calcifications and long-term survival and cardiovascular events (CVEs) in RTRs. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Two hundred seventy-seven prevalent RTRs from a single center were included. CVEs and deaths were prospectively recorded during a 5-year follow-up. RESULTS Independent determinants of lower serum fetuin-A levels were lower plasma cholesterol, the AHSG rs4918 G allele, and history of smoking. Low serum fetuin-A level was a determinant of aortic calcifications (assessed using spiral CT). Low fetuin-A levels (≤0.47 g/L, first quintile) were independently associated with CVEs and deaths (hazard ratio=1.83; 95% confidence interval, 1.07 to 3.04). The association was confirmed for all-cause mortality, and the major adverse cardiovascular endpoints were analyzed separately. Patients with low fetuin-A and high high-sensitivity C-reactive protein (>4.36 mg/L, fourth quintile) levels had a 3.5-fold increased risk of all-cause mortality and CVEs. In the presence of inflammation, CVE-free survival was influenced by common variants in the AHSG gene. CONCLUSIONS These data show that low fetuin-A levels are independently associated with aortic calcifications and a higher risk of CVEs and mortality. They support fetuin-A as a circulating biomarker able to identify RTRs at risk for vascular calcifications and CVEs.

Autosomal dominant polycystic kidney disease is associated with central and nephrogenic defects in osmoregulation

Autosomal dominant polycystic kidney disease (ADPKD) is associated with a urine-concentrating defect attributed to renal cystic changes. As PKD genes are expressed in the brain, altered central release of arginine vasopressin could also play a role. In order to help determine this we measured central and nephrogenic components of osmoregulation in 10 adults and 10 children with ADPKD, all with normal renal function, and compared them to 20 age- and gender-matched controls. Overnight water deprivation caused a lower rise in urine osmolality in the patients with ADPKD than controls, reflecting an impaired release of vasopressin and a peripheral defect in the patients. The reactivity of plasma vasopressin to water deprivation, as found in controls, was blunted in the patients with the latter showing lower urine osmolality for the same range of plasma vasopressin. The maximal urine osmolality correlated negatively with total kidney volume. Defective osmoregulation was confirmed in the children with ADPKD but was unrelated to number of renal cysts or kidney size. Thus, patients with ADPKD have an early defect in osmoregulation, with a blunted release of arginine vasopressin. This reflects expression of polycystins in hypothalamic nuclei that synthesize vasopressin, and this should be considered when evaluating treatments targeting the vasopressin pathway in ADPKD.

Disseminated Varicella Zoster Virus Infection in Adult Renal Transplant Recipients: Outcome and Risk Factors

BACKGROUND Disseminated varicella zoster virus (VZV) infection, whether due to primary infection or reactivation, may be life threatening in renal transplant recipients. The aims of this study were to assess the outcome of disseminated VZV infection in renal transplant recipients and to determine potential risk factors for mortality. METHODS A search of the English literature from 1985 to 2011 using PUBMED was performed. Reports involving renal transplant recipients younger than 16 years of age were excluded. RESULTS A total of 56 adult patients presenting with a disseminated cutaneous or visceral VZV infection was included. Seventy percent of cases occurred within 5 years after transplantation, and 89% within 10 years. Visceral complications including disseminated intravascular coagulation occurred in two thirds of patients. Mortality decreased significantly from 47% in the era before 1995 to 17% after 1995 (P = .04). Risk factors for mortality included visceral involvement, use of azathioprine as immunosuppressant, and longer time between transplantation and VZV infection. VZV seropositivity did not influence fatal outcome. CONCLUSION Disseminated VZV infection can be life threatening in renal transplant recipients with a global mortality rate of 30%. This rate seems to have decreased since 1995. Seropositive VZV patients with disseminated infection are not protected from fatal outcome.

Significant rate of hepatitis B reactivation following kidney transplantation in patients with resolved infection.

BACKGROUND Limited data is available on the risk of hepatitis B virus (HBV) reactivation in patients with resolved infection undergoing kidney transplantation. It is generally thought that this risk is negligible. OBJECTIVES To evaluate the incidence of HBV reactivation in such patients, and the potential risk factors for reactivation. STUDY DESIGN Retrospective cohort study including 93 patients transplanted with a kidney between 1995 and 2007 who had evidence of resolved HBV infection (HBsAg negative, anti-HBc positive, anti-HBs positive or negative, and normal liver enzymes). HBV reactivation was defined as HBsAg reversion with HBV DNA>2000 IU/mL. RESULTS Six patients experienced HBsAg reversion followed by HBV reactivation, 3 within the first post-transplant year. Immunosuppression regimen was similar in patients with and without reactivation. Among patients with reactivation only one was positive for anti-HBs antibodies at time of transplantation; these were progressively lost before reactivation. The odds ratio for reactivation in patients without anti-HBs antibodies at transplantation compared to those with anti-HBs antibodies was 26 (95% CI [2.8-240.5], p=0.0012). In patients with anti-HBs antibody titer above 100 IU/L, no reactivation was observed. CONCLUSIONS Reactivation rate of resolved hepatitis B is not negligible in patients without anti-HBs antibodies at transplantation. We suggest monitoring of liver tests and HBV serology including HBsAg and anti-HBs antibodies after transplantation as well as vaccination pre- and post-transplantation in all patients, including those with resolved hepatitis B, aiming at maintaining anti-HBs antibody level above 100 IU/L.

Recurrence and Graft Loss after Kidney Transplantation for Henoch–Schönlein Purpura Nephritis: A Multicenter Analysis

BACKGROUND AND OBJECTIVES The actuarial risk at 5 years for clinical recurrence of Henoch-Schönlein purpura nephritis (HSPN) and graft loss caused by recurrence of -HSPN after renal transplantation was reported in 1994 to be as high as 35% and 11%, respectively. The aim of this study is to re-evaluate, in a large cohort of patients with a long-term follow-up, whether these rates have changed. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Patients from six transplant centers in Belgium and France with strict diagnostic criteria of HSPN and a potential post transplant follow-up of ≥3 years were included. RESULTS Forty-three patients were included. Patient survival is excellent: 98%, 95%, and 95% at 5, 10, and 15 years, respectively. Overall graft survival rates were 84%, 66%, and 56% at 5, 10, and 15 years, respectively. Clinical recurrence in a first kidney transplant occurred in five patients. Three patients lost their first graft due to HSPN recurrence 19 to 96 months after transplantation, two of whom had systemic signs of the illness. Actuarial risk for clinical recurrence in a first graft is 2.5% and 11.5% at 5 and 10 years, respectively. Actuarial risk for graft loss caused by recurrence in a first graft is 2.5% and 7.5% at 5 and 10 years, respectively. Severity of the disease at presentation and type of immunosuppression after transplantation did not affect recurrence. CONCLUSIONS We found that recurrence rates of HSPN after transplantation are lower than previously reported. The actuarial risk of graft loss from recurrence in a first graft is 7.5% at 10 years.

Immunogenicity of an adjuvanted 2009 pandemic influenza A (H1N1) vaccine in haemodialysed patients

Abstract Background. The 2009 pandemic of influenza A (H1N1) prompted an urgent worldwide vaccination campaign, especially of high-risk subjects, such as maintenance haemodialysis (HD) patients. Still the immunogenicity of the pandemic A (H1N1) vaccine in HD patients is unknown. Methods. We prospectively studied the immunogenicity of a monovalent adjuvanted influenza A/California/2009 (H1N1) vaccine (Pandemrix®, GSK Biologicals, Rixensart, Belgium) in HD patients and controls. Antibody level was measured using a seroneutralization assay before (D0) and 30 days after (D30) a single 3.75 μg vaccine dose. Specimens were tested in quadruplicates. Geometric mean (GM) antibody titers were determined in each subject at D0 and D30. Seroconversion was defined as an increase in GM titers by a factor 4 or more. Results. Fifty-three adult HD patients [aged 71 ± 10, 58.5% males, on HD for a median of 38 (3 − 146) months] and 32 control subjects (aged 47.3 ± 14, 31.3% males) were analyzed. Baseline GM titers were similar in HD patients and controls [7.9 (6.6 − 9.6) vs 10 (6 − 17); p = 0.69]. Seroconversion was observed in 30 (93.8%) controls and 34 (64.2%) HD patients (p = 0.002). In addition, GM titers at D30 were significantly higher in controls than in HD patients [373 (217 − 640) vs 75.5 (42.5 − 134); p = 0.001]. HD patients were significantly older than controls (p < 0.001) and more likely to be males (p = 0.02). However, by multivariate analysis, HD status [OR 0.13 (0.02-0.78), p = 0.03], but neither age [OR 0.99 (0.96 − 1.03); p = 0.7] nor male gender [OR 1.31 (0.45 − 3.85); p = 0.63] was independently associated with seroconversion. The vaccine was generally well tolerated by HD patients. Conclusions. Only 64% of chronic HD patients developed seroconversion after a single dose of adjuvanted influenza A (H1N1) vaccine, a much lower rate than in controls (94%). These results underscore the substantial immunodeficiency associated with End-Stage Renal Disease. The persistence of protective antibodies as well as the effect of a booster dose remain to be investigated in HD patients.

Double-dose icodextrin to increase ultrafiltration in PD patients with inadequate ultrafiltration.

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