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Bart Maes

Publications and source records attributed to Bart Maes.

At least 37 records · Page 2Linked to original sources
PubMed2004

A prospective proof of concept study of the efficacy of tacrolimus ointment on uraemic pruritus (UP) in patients on chronic dialysis therapy.

BACKGROUND: Uraemic pruritus (UP) is a serious symptom of chronic dialysis patients and patients with end-stage renal disease. UP causes skin damage, discomfort, sleeping disorders and diminished quality of life. Since UP is considered to be in part an immune-mediated inflammatory process, immunosuppressive drugs like tacrolimus may be beneficial. METHODS: We conducted a prospective study on the effect of 6 weeks treatment with two sequential concentrations of tacrolimus ointment on the severity of UP in chronic dialysis patients and again after 2 weeks wash-out. Twenty-five patients with UP were enrolled in the study; 21 patients completed the study. UP was measured using a validated modified pruritus assessment score and a Visual Analogue Scale (VAS). RESULTS: The modified pruritus assessment score decreased significantly by 81.8% after 6 weeks treatment from [median score 11 (interquartile range: IQR 6-16) on day 0 to median score 2 (IQR 0-5.25) at week 6: P<0.0001]. After 2 weeks wash-out, the median score returned to 72.7% of baseline levels [8 (IQR 2-16)]. Using the VAS score an identical evolution could be demonstrated. Tacrolimus ointment was well tolerated and no serious adverse events were noted. Transient stinging and burning sensation was reported by four patients in the first weeks of the trial, one patient suffered a mild skin rash. No systemic exposure to tacrolimus was detected. CONCLUSION: This prospective study has shown that 6 weeks treatment with tacrolimus ointment significantly reduces the severity of UP in chronic dialysis patients and is well tolerated. Randomized placebo-controlled studies are necessary to confirm these encouraging preliminary results.

Female↗
PubMed2004

Natural history of parathyroid function and calcium metabolism after kidney transplantation: a single-centre study.

BACKGROUND: The natural history of parathyroid function after successful renal transplantation (RT) and the factors predisposing to persistent hyperparathyroidism (HPT) are not well established. A better knowledge of these data may be helpful in the development of algorithms for optimal surveillance and treatment of HPT after successful RT. Our aim was to evaluate the post-transplant natural history of parathyroid function and calcium metabolism in patients with a functional renal graft and to identify risk factors for persistent HPT. METHODS: Charts of 1165 allograft kidney recipients transplanted between 1989 and 2000 were reviewed. Patients with an intact parathyroid hormone (iPTH) level available at the time of transplantation were identified. The charts of the latter patients were checked for a variety of demographic and clinical data, and all determinations of the iPTH concentration available since transplantation were recorded. Serum levels of calcium, phosphorus, alkaline phosphatases and creatinine, concurrently determined, were also registered. RESULTS: After an initial fall, iPTH levels showed a slow but steady decline towards the upper normal limit. The prevalence of persistent HPT, defined as an iPTH level > or =2.5 times the upper normal limit or the need for parathyroidectomy following transplantation, remained stable at approximately 17% up to 4 years after transplantation. Patients with persistent HPT had significantly elevated serum levels of iPTH, calcium and phosphorus at the time of RT, and had spent a longer time on dialysis. Post-transplant iPTH levels correlated significantly with transplant kidney function. CONCLUSION: Kidney transplant recipients with a high iPTH and calcium x phosphate product at the time of transplantation are at risk for persistent HPT especially when renal function is suboptimal. Therapy for persistent HPT, if considered, should be initiated 3 months post-transplantation since further spontaneous improvement of parathyroid function thereafter is limited.

Calcium↗
PubMed2004

Clinical efficacy and toxicity profile of tacrolimus and mycophenolic acid in relation to combined long-term pharmacokinetics in de novo renal allograft recipients.

INTRODUCTION: Tacrolimus and mycophenolate mofetil are effective drugs characterized by specific toxicity profiles that may compromise their long-term use in renal transplant recipients. Clinicians, therefore, need reliable drug monitoring tools for relating efficacy and toxicity to drug exposure. Study design We conducted a prospective 12-month pharmacokinetic study of tacrolimus and mycophenolic acid in 100 de novo recipients. The aim was to examine whether tacrolimus and mycophenolic acid exposure parameters (predose trough blood concentration [C(0)], area under the concentration curve from 0 to 12 hours [AUC(0-12)], maximum blood or plasma concentration [C(max)], and dose) would reflect clinical efficacy and toxicity at different time points after transplantation (7 days, 6 weeks, and 3, 6, and 12 months). RESULTS: Initially, after grafting, the tacrolimus AUC(0-12) was higher in recipients with infection (P =.01 on day 7, P =.02 at week 6), whereas the mycophenolic acid AUC(0-12) was not different. There was no difference in tacrolimus exposure between patients who had arterial hypertension or hyperlipidemia and those who did not. Patients with tacrolimus nephrotoxicity received a higher drug dose (P =.03) and had higher drug clearance (P =.02). From 3 months, recipients with anemia or leukopenia had higher mycophenolic acid AUC(0-12) (anemia, P =.03 at month 3 and P =.01 at month 12; leukopenia, P =.01 at month 3 and P =.04 at 1 year) and C(0) (anemia, P =.001 at month 3 and P =.001 at month 12; leukopenia, P =.01 at month 3 and P =.04 at 1 year). Finally, for recipients who did not simultaneously have a target tacrolimus AUC(0-12) of 150 ng x h/mL and a mycophenolic acid AUC(0-12) of 45 mg x h/L by day 7, the incidence of acute rejection tended to be higher (26.3%) compared with patients who reached both target values (7.7%) (P =.07). CONCLUSIONS: Pharmacokinetic exposure parameters of tacrolimus and mycophenolic acid are related to specific drug-induced side effects in a time-dependent fashion. In addition, this study has provided a conceptual basis for defining a combined target therapeutic window for tacrolimus and mycophenolic acid based on sparse AUC(0-12) measurements.

Area Under Curve↗
PubMed2004

Performance of ViroSeq HIV-1 Genotyping System in routine practice at a Belgian clinical laboratory.

Since there are indications of an increasing amount of non-B subtypes in Western Europe it was decided to assess the performance of the ViroSeq HIV-1 Genotyping System on a set of samples from the AIDS Reference Laboratory at the University Hospitals Leuven, a hospital with an increasing number of patients infected with non-B subtypes. The set consisted of 383 samples comprising 12 different subtypes and the genotyping kit was assessed for its amplification capabilities as well as its sequencing capabilities. Amplification failed in 32 samples (8.4%) and there was a tendency of a lower performance of the kit when it concerned the amplification of non-B subtypes. Regarding the sequencing performance of the HIV-1 Genotyping System, three different results could be considered. The performance of the entire set of primers (A, B, C, F, G and H) on the different subtypes showed a significant decrease of positive results for subtypes A, G and the recombinants whereas a tendency to less positive results could be detected for subtypes CRF12_BF, D, H and J. When looking at the performance of the individual primers for the different subtypes, only one result differed significantly: there were less positive results by applying primer F on subtype A. A tendency to less positive results was found for other combinations of primer and subtype, most of which comprised combinations with primers B, C, F and H. A final result was obtained by comparing the overall sequencing results of a certain primer on all the non-B subtypes with the results of the same primer on subtype B. Primer F showed significant less positive results and a tendency to less positive results was found for primer H. The other primers showed comparable results. All of the above results regarding the sequencing primers did not include primer D since this is a back-up primer for primer A. Analysis of the results for primer D showed that less positive results were found for all the non-B subtypes, most of which were significant. The overall performance of primer D on all non-B subtypes was only 15.7%. The use of primer D as a back-up primer was also investigated: it generated a positive result in only 17.3% of the cases where primer A failed. Most of these positive results were subtype B (74%). As a result of sequencing problems 65 out of 351 (18.5%) samples had to be processed with "in-house" procedures.

Belgium↗
PubMed2004

Effect of fluvastatin on renal end points in the Assessment of Lescol in Renal Transplant (ALERT) trial.

BACKGROUND: Hyperlipidemia is a risk factor for long-term renal transplant dysfunction, but no prospective clinical trials have investigated the effects of statin treatment on graft function in renal transplant recipients. The aim of the present study was to evaluate the effect of fluvastatin on long-term renal transplant function and development of chronic allograft nephropathy in the ALERT (Assessment of Lescol in Renal Transplantation) study. METHODS: ALERT was a randomized, double-blind, placebo-controlled study of the effect of fluvastatin, 40 mg and 80 mg daily, in renal transplant recipients. Patients were randomized to receive either fluvastatin (N= 1050) or placebo (N= 1052) and followed for five to six years. Renal end points included graft loss or doubling of serum creatinine or death; glomerular filtration rate (GFR) was also measured during follow-up in a subset of patients (N= 439). RESULTS: There were 283 patients (13.5%) with graft loss, mainly due to chronic rejection (82%), yielding an annual rate of 2.4%. Fluvastatin treatment significantly lowered mean low-density lipoprotein (LDL)-cholesterol levels by 32% (95% CI -33 to -30) compared with placebo, but had no significant effect on the incidence of renal graft loss or doubling of serum creatinine, or decline in GFR throughout follow-up in the whole study population. Neither was any treatment effect by fluvastatin found in any of the subgroups analyzed. CONCLUSION: Fluvastatin treatment significantly improves lipid values in renal transplant recipients but has no effect on graft loss or doubling of serum creatinine.

Adult↗
PubMed2004

fluvastatin prevents cardiac death and myocardial infarction in renal transplant recipients: post-hoc subgroup analyses of the ALERT Study.

Renal transplant recipients have a greatly increased risk of premature cardiovascular disease. The ALERT study was a multicenter, randomized, double-blind, placebo-controlled trial of fluvastatin (40-80 mg/day) in 2102 renal transplant recipients followed for 5-6 years. The main study used a composite cardiac end-point including myocardial infarction, cardiac death and cardiac interventions. Although reduced by fluvastatin, this primary end-point failed to achieve statistical significance thus precluding analysis of predefined subgroups. Therefore, in the present survival analysis, we used an alternative primary end-point of cardiac death or definite nonfatal myocardial infarction (as used in other cardiac outcome trials) which was significantly reduced by Fluvastatin therapy and permits subgroup analysis. Fluvastatin reduced LDL-cholesterol by 1 mmol/L compared with placebo, and the incidence of cardiac death or definite myocardial infarction was reduced from 104 to 70 events (RR 0.65; 95% CI 0.48, 0.88; p = 0.005). Fluvastatin use was associated with reduction in cardiac death or nonfatal myocardial infarction, which achieved statistical significance in many subgroups. The subgroups included patients at lower cardiovascular risk, who were younger, nondiabetic, nonsmokers and without pre-existing CVD. These data support the early introduction of statins following renal transplantation.

Adult↗
PubMed2004

Prospective study on late consequences of subclinical non-compliance with immunosuppressive therapy in renal transplant patients.

In this prospective study we compared the incidence of late acute rejections (LAR) and changes in serum-creatinine over time between compliers and noncompliers with immunosuppressive therapy more than 1 year post transplantation and explored the relative contribution of non-compliance and other risk factors in the occurrence of LAR. One hundred and forty-six adult renal transplant recipients were followed during a 5-year period. Patients were interviewed at the beginning of the study and categorized as non-compliers if they admitted to have skipped immunosuppressive medication on a regular basis during the previous 12 months. The occurrence of LAR during the follow-up period was recorded. We identified 22.6% non-compliers of which 21.2% experienced a late acute rejection compared with 8% in the group of compliers at 5 years postinclusion (p < 0.05). Kaplan-Meier survival analysis showed a decreased rejection free time in non-compliers compared with compliers (p = 0.03). Non-compliant patients had a 3.2 higher risk of LAR (Cox regression analysis, p = 0.005). Non-compliers experienced a higher increase in serum-creatinine over time (Linear Mixed Models, p < 0.001). Non-compliance in renal transplant patients more than 1-year post transplantation is associated with an increased risk for LAR and a higher increase in serum-creatinine during the following 5 years.

Adult↗
PubMed2004

Combined 'en bloc' liver and pancreas transplantation in patients with liver disease and type 1 diabetes mellitus.

Liver disease alters the glucose metabolism and may cause diabetes, but this condition is potentially reversible with liver transplantation (LTx). Type 1 diabetes mellitus may be coincidentally present in a LTx candidate and immunosuppressive drugs will aggravate diabetes and make its management more difficult for posttransplant. In addition, diabetes negatively influences outcome after LTx. Therefore, the question arises as to why not transplanting the pancreas in addition to the liver in selected patients suffering from both liver disease and Type 1 diabetes. We report two cases of en bloc combined liver and pancreatic transplantation, a technique originally described a decade ago in the treatment of upper abdominal malignancies but rarely used for the treatment of combined liver disease and Type 1 diabetes. Both recipients are currently liver disease-free and insulin-free more than 2 and 4 years posttransplant, respectively. Surgical, medical and immunological aspects of combined liver-pancreas transplantation are discussed in the light of the existing relevant literature.

Adult↗
PubMed2004

Time-related clinical determinants of long-term tacrolimus pharmacokinetics in combination therapy with mycophenolic acid and corticosteroids: a prospective study in one hundred de novo renal transplant recipients.

BACKGROUND: Tacrolimus is an efficient primary immunosuppressive drug in renal transplantation but its long-term use is associated with calcineurin-inhibitor-related toxicity. The specific characteristics of the inter-relationship between dose, concentration and clinical (side-)effects for tacrolimus have not yet been identified and extensive long-term pharmacokinetic studies are presently lacking. OBJECTIVE: To establish the characteristics of the long-term pharmacokinetics of tacrolimus, to determine the time-dependent factors that influence the pharmacokinetics within the first critical post-transplant year and to identify a more appropriate way of monitoring drug exposure in clinical practice. STUDY DESIGN: A prospective pharmacokinetic study of tacrolimus was conducted in 100 de novo renal allograft recipients during the first year post-transplantation. METHODS: Area under the concentration-time curve (AUC) blood samplings for tacrolimus were performed on days 7, 42, 90, 180 and 360 for all patients. Model-independent pharmacokinetic parameters for tacrolimus were calculated and dose-corrected when appropriate: AUC12, peak plasma concentration (Cmax), pre-dose trough concentration (C0), time to Cmax, average steady-state blood concentration, steady-state total body clearance, terminal half-life, volume of distribution and an estimate for tacrolimus bioavailability was derived from additional steady-state intravenous clearance data. The association between tacrolimus pharmacokinetic parameters and different clinical variables was evaluated on days 7, 42, 90, 180 and 360. The clinical variables were either donor-related (e.g. donor age), transplantation-related (e.g. delayed graft function), recipient-related (e.g. bodyweight), biochemical (e.g. serum albumin), therapeutic variables (e.g. corticosteroid dose) or disease variables (e.g. liver dysfunction). RESULTS: Long-term tacrolimus dose-corrected exposure (AUC12, C0) is characterised by a late significant increase towards the end of the first year post-transplantation as the result of a significant increase in tacrolimus bioavailability (p < 0.05) and a slow decrease in tacrolimus steady-state clearance. Consequently, tacrolimus dose-requirements corrected for bodyweight decrease significantly in the first postoperative year (p < 0.05), in part because of the simultaneous tapering of the corticosteroid dose which significantly affects tacrolimus bioavailability (p < 0.05). Other clinical variables that significantly influenced tacrolimus administration, exposure and bioavailability in a time-related fashion were identified in this study (renal allograft function [p < 0.05], liver dysfunction [p < 0.05], diarrhoea [p < 0.05]), while the clinical relevance of other variables was considerably moderated by our findings (serum albumin, haematocrit). Time-unrelated variables proved to be of significant continuing clinical importance for tacrolimus dose-exposure pharmacokinetics throughout the first post-transplant year (recipient age [p < 0.05], gender [p < 0.01] and donor-receptor gender mismatch [p < 0.05]), while donor hypotension (p < 0.05) and cold ischaemia time (p < 0.05) also proved significant although at present the reasons for this are unknown. Finally, using multiple stepwise regression analysis we demonstrated that classical assessment of tacrolimus exposure by monitoring pre-dose trough blood concentration (or any other single concentration sampling timepoint) is not the most reliable method and that abbreviated AUC measurements may constitute a more accurate clinical tool for (therapeutic) monitoring of drug exposure. CONCLUSION: Tacrolimus pharmacokinetics in the first year after renal transplantation are characterised by a specific time-dependent evolution. The identification of clinical variables that determine tacrolimus pharmacokinetics is an important aid in the development of reliable drug monitoring strategies using abbreviated AUC measurements.

Adrenal Cortex Hormones↗
PubMed2003

Performance of the VERSANT HIV-1 resistance assays (LiPA) for detecting drug resistance in therapy-naive patients infected with different HIV-1 subtypes.

In this study we evaluated the performance of the VERSANT HIV-1 Resistance Assays (LiPA) in detecting drug resistance in therapy-naive HIV-infected patients diagnosed in Belgium in 2000. We compared the results with population sequencing and found concordance to be in line with previous studies in treatment-experienced patients (86.87% for reverse transcriptase (RT); 92.77% for protease (PRO)). Discordance was mainly due to indeterminate reactions on LiPA (8.45% for RT; 6.85% for PRO) and minor discordances (4.13% for RT; 0.25% for PRO). Major discordances were rare (0.46% for RT; 0.12% for PRO). Indeterminate reactions were significantly associated with strains belonging to non-B subtypes.

Anti-HIV Agents↗
PubMed2003

C3D deposition in peritubular capillaries indicates a variant of acute renal allograft rejection characterized by a worse clinical outcome.

BACKGROUND: C4d deposition in peritubular capillaries (PTCs) is a sign of humoral renal allograft rejection and an independent predictor of graft survival. Few investigators have focused on the meaning of capillary C3 deposition in rejecting grafts. Because C3 production can result from both classic and alternative pathway activation of the complement cascade, it is not clear whether C3 deposition indicates a distinct entity of acute rejection (AR) or merely represents a separate form of C4d-positive AR. METHODS: We examined the deposition of C3d in the PTCs of recipients with AR in the first year posttransplantation (n=30). Clinical outcome variables and histology were compared with C3d-negative control patients (n=82). RESULTS: C3d-positive patients demonstrated more frequent preexisting T-cell antibodies (57%) and more re-transplants (37%), and they received more blood transfusions (mean 10.3 units). C3d-positive patients experienced more frequent multiple AR episodes (57%) and delayed graft function (36.7%). All nine C3d-positive recipients screened for posttransplantation donor-specific human leukocyte antigen antibodies demonstrated positive results. Graft failure occurred in 23% of C3d-positive recipients (7.3% in the control group) (P=0.03). C3d-positive biopsies showed significantly less tubulitis (P=0.03), whereas congestive PTCs with intraluminal accumulation of polymorphonuclear leukocytes were conspicuous. Thrombi, fibrinoid necrosis, and acute tubular necrosis were not more pronounced. In 19% of rejection biopsies, C3d deposition in PTCs was present without C4d deposition. In the remaining biopsies, C3d and C4d deposition was found simultaneously. CONCLUSIONS: The deposition of complement factor C3d in PTCs indicates a variant type of AR characterized by a worse clinical outcome.

Acute Disease↗
PubMed2003

Effect of fluvastatin on cardiac outcomes in renal transplant recipients: a multicentre, randomised, placebo-controlled trial.

BACKGROUND: Renal transplant recipients are at increased risk of premature cardiovascular disease. Although statins reduce cardiovascular risk in the general population, their efficacy and safety in renal transplant recipients have not been established. We investigated the effects of fluvastatin on cardiac and renal endpoints in this population. METHODS: We did a multicentre, randomised, double-blind, placebo-controlled trial in 2102 renal transplant recipients with total cholesterol 4.0-9.0 mmol/L. We randomly assigned patients fluvastatin (n=1050) or placebo (n=1052) and follow up was for 5-6 years. The primary endpoint was the occurrence of a major adverse cardiac event, defined as cardiac death, non-fatal myocardial infarction (MI), or coronary intervention procedure. Secondary endpoints were individual cardiac events, combined cardiac death or non-fatal MI, cerebrovascular events, non-cardiovascular death, all-cause mortality, and graft loss or doubling of serum creatinine. Analysis was by intention to treat. FINDINGS: After a mean follow-up of 5.1 years, fluvastatin lowered LDL cholesterol concentrations by 32%. Risk reduction with fluvastatin for the primary endpoint (risk ratio 0.83 [95% CI 0.64-1.06], p=0.139) was not significant, although there were fewer cardiac deaths or non-fatal MI (70 vs 104, 0.65 [0.48-0.88] p=0.005) in the fluvastatin group than in the placebo group. Coronary intervention procedures and other secondary endpoints did not differ significantly between groups. INTERPRETATION: Although cardiac deaths and non-fatal MI seemed to be reduced, fluvastatin did not generally reduce rates of coronary intervention procedures or mortality. Overall effects of fluvastatin were similar to those of statins in other populations.

Adult↗