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Bart Maes

Publications and source records attributed to Bart Maes.

At least 19 recordsLinked to original sources
PubMed2006

Genotypic drug resistance interpretation algorithms display high levels of discordance when applied to non-B strains from HIV-1 naive and treated patients.

Genotypic drug resistance interpretation algorithms have been developed on patients infected with HIV-1 subtype B to interpret complex patterns of mutations. As non-B strains are characterised by the natural presence of several resistance-related mutations, we examined to what extent this might result in interalgorithm discordances in naive and treated patients. We compared the prediction by three algorithms (ANRS, Stanford and Rega) of drug susceptibilities to diverse HIV-1 strains from 272 naive and 156 treated patients. In naive patients, higher levels of interalgorithm discordance were observed for predictions of protease inhibitor (0.60-39%) than for predictions of reverse transcriptase inhibitor susceptibility (0-4%). The main reason for discordant protease inhibitor interpretation was the presence of resistance mutations that were natural protease polymorphisms. In contrast, in the treated patients, more interalgorithm discordances were observed for predictions of reverse transcriptase inhibitor (5-48%) than protease inhibitor susceptibilities (10-31%). Discordances were related to disagreement between the intermediate and susceptible scores, the intermediate and resistant scores and the interpretations of complex mutation patterns, related to cross-resistance and antagonistic interactions.

Algorithms↗
PubMed2005

Long-term efficacy and tolerability of lanthanum carbonate: results from a 3-year study.

BACKGROUND: Control of serum phosphate over the long term is essential in patients with end-stage renal disease. Six-month and 2-year extensions to a 6-month study evaluated the long-term safety, tolerability and efficacy of the new phosphate binder lanthanum carbonate. METHODS: Patients who participated in a 6-month, randomized trial comparing lanthanum carbonate with calcium carbonate were eligible for a 24-week, open-label extension. Lanthanum carbonate-treated patients continued taking their established maintenance dose ('continued-lanthanum group') and calcium carbonate-treated patients switched to lanthanum carbonate, 375-3,000 mg/day ('switch group'). Patients could also enter a further 2-year extension. Efficacy parameters, including serum phosphate, were monitored. RESULTS: Mean serum phosphate was approximately 1.80 mmol/l throughout the trial. The percentage of patients with controlled serum phosphate (< or =1.80 mmol/l) after the 6-month extension was 63.3 and 58.4% in the continued-lanthanum and switch groups, respectively; after the 2-year extension, 54.4% of patients had controlled serum phosphate. After discontinuation of calcium carbonate and initiation of lanthanum carbonate, the hypercalcemia incidence was 2.7%, compared with 20.2% during the double-blind phase. Calcium x phosphate product was maintained at an acceptable level. Lanthanum carbonate was well tolerated; adverse events were mild/moderate and mainly gastrointestinal. CONCLUSIONS: Lanthanum carbonate maintains effectiveness with continued tolerability for up to 3 years.

Adult↗
PubMed2005

Detoxifying capacity and kinetics of prometheus--a new extracorporeal system for the treatment of liver failure.

BACKGROUND/AIMS: Extracorporeal liver support therapies have been used for several decades as a bridging therapy prior to liver transplantation or as an addendum to standard medical therapy. The Prometheus system represents a cell-free, extracorporeal, liver assist method for the removal of both albumin-bound and water-soluble endogenous toxins. The aim of the present study was to evaluate the removal capacity and selectivity of the different inbuilt dialyzers and adsorption columns during a single 6-hour treatment. METHODS: Nine patients with acute on chronic liver failure were included (6 females, age 49+/- 4 years). Levels of endogenous toxins (urea nitrogen [UN, mg/dl], creatinine [Cr, mg/dl], total bilirubin [tB, mg/dl], and bile acids [BA, mumol/l]) and albumin [Alb, g/l] were monitored in blood sampled at different sites (arterial line, venous line and between the absorbers and the high-flux dialyzer) and at various time points (time 0, 30, 60, 120, 240, and 360 min). RESULTS: A significant decrease of the serum level of all toxins was observed (UN 108.7+/- 23.2 vs. 38.1+/- 14.9, Cr 2.4+/- 0.7 vs. 1.2+/- 0.3, tB 31.1+/- 4.1 vs. 17.0+/- 1.6, BA 155.7+/- 32.5 vs. 66.0+/- 15.4; mean+/- SEM, time 0 vs. time 360, signed rank rest, all p< 0.005). The reduction rate of UN, Cr, tB and BA amounted to 68.1+/- 5.1, 45.9+/- 6.2, 41.2+/- 5.1, and 58.2+/- 5.0%, respectively. Blood clearances [Cl, ml/min] of all, but especially of the protein-bound toxins declined over time (Cl UN 171.5+/- 4.3 vs. 142.9+/- 16.8; Cl Cr 135.7+/- 10.0 vs. 111.8+/- 9.1; Cl tB 29.3+/- 5.1 vs. 13.7+/- 3.7; Cl BA 84.9+/- 4.8 vs. 45.1+/- 13.3; time 30 vs. time 360; linear mixed models, all p< 0.005). Serum albumin levels decreased by 2.9+/- 0.9 g/l (signed rank test, p=0.055). Not unexpectedly, tB was almost uniquely cleared by the adsorbers (UN 0.2+/-1.1, Cr 6.9+/- 5.7, tB 92.3+/- 4.2, BA 62.9+/- 3.9% of total Cl). CONCLUSION: Both albumin-bound and water-soluble toxins are adequately removed by the Prometheus system. Our data suggest that the rate and efficacy of removal of albumin-bound toxins is related to both the strength of the albumin binding and the saturation of the adsorption columns. Limited losses of albumin occur during treatment with the Prometheus system.

Bile Acids and Salts↗
PubMed2005

Impact of parathyroidectomy on renal graft function, blood pressure and serum lipids in kidney transplant recipients: a single centre study.

BACKGROUND: Successful kidney transplantation is believed to reverse secondary hyperparathyroidism, but persistent disease has emerged in a significant number of allograft recipients. Parathyroid hormone (PTH) is not only involved in the aetiology of calcium/phosphate abnormalities and osteitis fibrosa, but it is also a permissive factor in the occurrence of hypertension, cardiovascular damage and dyslipidaemia. In experimental renal failure, abrogation of hyperparathyroidism by administration of a calcimimetic or parathyroidectomy (PTX) attenuates progression of renal failure. To evaluate the impact of PTX on blood pressure (BP), renal graft function and serum lipids, we performed a retrospective case-controlled study in renal graft recipients. METHODS: Charts of 1647 kidney allograft recipients, transplanted between 1989 and 2004, were reviewed. Thirty-two patients with a functioning graft and a history of a successful PTX performed at least 9 months after transplantation were identified. Biochemical and clinical data available 6 months pre- and post-PTX were registered. Changes in BP, renal function and serum lipids were assessed. The data were compared with those obtained in a similar time frame in a control group closely matched for date of transplantation. RESULTS: Systolic BP (149.9 vs 141.7 mmHg), diastolic BP (85.6 vs 81.9 mmHg), pulse pressure (64.3 vs 58.8 mmHg), total cholesterol concentration (221.4 vs 211.1 mg/dl) and low-density lipoprotein cholesterol concentration (123.9 vs 106.7 mg/dl) improved significantly after successful PTX. Serum creatinine, conversely, significantly increased after PTX (1.75 vs 2.13 mg/dl, P<0.0001). No significant changes were observed in the control group in the same time period. CONCLUSION: In patients with a functioning renal graft, BP and dyslipidaemia improve, whereas serum creatinine worsens following successful PTX. Our data are in agreement with a stimulatory effect of PTH on plasma renin activity and an inhibitory effect on lipase activity, as previously demonstrated by others. To what extent the increased serum creatinine following PTX reflects a true deterioration of the glomerular filtration rate and/or is the consequence of vitamin D-induced reduction of the renal tubular secretion of creatinine needs to be elucidated by further research.

Blood Pressure↗
PubMed2005

Renal dysfunction as a risk factor for mortality and cardiovascular disease in renal transplantation: experience from the Assessment of Lescol in Renal Transplantation trial.

BACKGROUND: Renal-transplant recipients have shortened life expectancy primarily because of premature cardiovascular disease. Traditional and nontraditional risk factors for cardiovascular disease are prevalent in renal patients. In renal-transplant recipients, immunosuppressive therapy can be nephrotoxic and aggravate cardiovascular disease risk factors. Renal dysfunction has been established as a risk factor for cardiovascular disease and mortality in different populations. We evaluated the effects of baseline renal-transplant function on mortality and cardiovascular and renal endpoints in 1,052 placebo-treated patients of the Assessment of Lescol in Renal Transplantation trial. METHODS: All renal-transplant recipients were on cyclosporine-based immunosuppressive therapy. Follow-up was 5 to 6 years, and endpoints included cardiac death, noncardiovascular death, all-cause mortality, major adverse cardiac event (MACE), stroke, nonfatal myocardial infarction, and graft loss. RESULTS: Baseline serum creatinine was strongly and independently associated with increased cardiac, noncardiovascular, and all-cause mortality, as well as MACE and graft loss. Serum creatinine was not a risk factor for stroke or nonfatal myocardial infarction. CONCLUSIONS: Elevated baseline serum creatinine in renal-transplant recipients is a strong and independent risk factor for all-cause, noncardiovascular and cardiac mortality, MACE, and graft loss.

Adult↗
PubMed2005

Beneficial effect of early initiation of lipid-lowering therapy following renal transplantation.

BACKGROUND: Renal transplant recipients have a significantly reduced life expectancy, largely due to premature cardiovascular disease. The aim of the current analysis was to investigate the importance of time of initiation of therapy after transplantation, on the benefits of statin therapy. METHODS: 2102 renal transplant recipients with total cholesterol levels of 4.0-9.0 mmol/l were randomly assigned to treatment with fluvastatin (n = 1050) or placebo (n = 1052) and followed for a mean time of 5.1 years. The end-points were major cardiac events. The average median time from transplantation to randomization was 4.5 years (range: 0.5-29 years). RESULTS: In patients starting treatment with fluvastatin <4.5 years after renal transplantation, the incidence of cardiac events was 4.6% over 5.1 years vs 9.2% in those on placebo (P = 0.007). Fluvastatin significantly reduced the risk of cardiac death and non-fatal myocardial infarction by 56% [risk ratio (RR): 0.44; 95% confidence interval (95% CI): 0.26-0.74; P = 0.002]. In a more detailed analysis patients were grouped into 2-year intervals (since the last transplantation). The frequency of cardiac death and non-fatal myocardial infarction was reduced by 3.2%, 5.1%, 9.6% and 8.2% with fluvastatin treatment as compared to 6%, 10.4%, 13.4% and 9.6% with placebo when treatment was initiated at 0-2, 2-4, 4-6 and >6 years, respectively. The risk reduction for patients initiating therapy with fluvastatin at years 0-2 (compared with >6 years) following transplantation was 59% (RR: 0.41; 95% CI: 0.18-0.92; P = 0.0328). This is also reflected in total time on renal replacement therapy: in patients in the first quartile (<47 months) fluvastatin use was associated with a risk reduction of 64% compared with 19% for patients in the fourth quartile (>120 months) (P = 0.033). CONCLUSIONS: Our data support an early introduction of fluvastatin therapy in a population of transplant recipients at high risk of premature coronary heart disease.

Adult↗
PubMed2005

A simplified strategy for clinical management of late cytomegalovirus infection after oral ganciclovir prophylaxis in renal recipients.

OBJECTIVES: Late cytomegalovirus disease after completion of prophylactic therapy occurs in 5-21% of renal allograft recipients within the first year post-transplantation. Identifying patients at risk for late infection is clinically difficult; prolonged cytomegalovirus (CMV) monitoring is costly and cumbersome as follow-up intervals lengthen. PATIENTS AND METHODS: We performed a prospective 1 year study in 54 de novo renal recipients to assess the minimum CMV monitoring frequency for identifying patients at risk. RESULTS AND CONCLUSIONS: CMV DNA PCR monitoring on the last day, and again 2 weeks after conclusion of oral ganciclovir prophylaxis, seemed sufficient for identifying recipients at risk for developing clinically relevant late CMV disease and for whom closer clinical follow-up is warranted.

Administration, Oral↗
PubMed2005

Risk factors for reaching renal endpoints in the assessment of Lescol in renal transplantation (ALERT) trial.

BACKGROUND: The aim of the study was to identity risk factors for long-term renal transplant function and development of chronic allograft nephropathy (CAN) in renal transplant recipients included in the Assessment of Lescol in Renal Transplantation (ALERT) trial. METHODS: The ALERT trial was a randomized, double-blind, placebo-controlled study of the effect of fluvastatin, 40 and 80 mg/day, in renal transplant recipients who were randomized to receive fluvastatin (Lescol) (n = 1,050) or placebo (n = 1,052) over 5 to 6 years of follow-up. Renal endpoints including graft loss or doubling of serum creatinine or death were analyzed by univariate and multivariate regression analysis in the placebo group. RESULTS: There were 137 graft losses (13.5%) in the placebo group, mainly caused by CAN (82%). Univariate risk factors for graft loss or doubling of serum creatinine were as follows: serum creatinine, proteinuria, hypertension, pulse pressure, time since transplantation, donor age, human leukocyte antigen-DR mismatches, treatment for rejection, low high-density lipoprotein cholesterol, and smoking. Multivariate analysis revealed independent risk factors for graft loss as follows: serum creatinine (relative risk [RR], 3.12 per 100-microM increase), proteinuria (RR, 1.64 per 1-g/24 hr increase), and pulse pressure (RR, 1.12 per 10 mm Hg), whereas age was a protective factor. With patient death in the composite endpoint, diabetes mellitus, smoking, age, and number of transplantations were also risk factors. CONCLUSIONS: Independent risk factors for graft loss or doubling of serum creatinine or patient death are mainly related to renal transplant function, proteinuria, and blood pressure, which emphasizes the importance of renoprotective treatment regimens in this population.

Adult↗
PubMed2005

A prospective, randomized, double-blind crossover study on the use of 5% citrate lock versus 10% citrate lock in permanent hemodialysis catheters.

Central venous catheters are used as permanent vascular access for chronic hemodialysis when construction of an arteriovenous fistula is not possible or contraindicated. We prospectively evaluated the efficacy and safety of a 5% citrate versus 10% citrate catheter lock for permanent single-lumen dialysis catheters in a double-blind, crossover study of 28 patients during 1,876 dialysis sessions. There was a slightly higher number of dialysis sessions with clot formation in the 5% citrate group; entirely attributable to the formation of small clots. There was no statistically significant difference in the formation of large clots, complete obstruction of the catheter or the need for urokinase between the 2 study groups. In view of the ongoing debate on the safety of high-concentration citrate catheter locks, we conclude that a 5% citrate lock is equally efficient in preventing catheter dysfunction compared with a 10% citrate lock and is therefore the preferred citrate catheter-locking solution.

Aged↗
PubMed2005

Acute-onset, steroid-sensitive, encapsulating peritoneal sclerosis in a renal transplant recipient.

Encapsulating peritoneal sclerosis is a severe complication of peritoneal dialysis. Immunosuppressive drugs have been claimed to be helpful in the treatment of this disease, although the pathophysiological background is poorly understood. In this report, we present a patient with encapsulating peritoneal sclerosis after successful renal transplantation. Maintenance immunosuppressive therapy consisted of mycophenolate mofetil, tacrolimus, and low-dose corticosteroids. The patient was treated successfully with high doses of corticosteroids. A subsequent relapse of the encapsulating peritoneal sclerosis, probably resulting from fast tapering of the corticosteroid dose, responded well to an increase in corticosteroid dose. Our case strongly supports a therapeutic role for high-dose steroids in the treatment of encapsulating peritoneal sclerosis during its initial inflammatory stage.

Acute Disease↗
PubMed2005

Cardiovascular risk and renal transplantation: post hoc analyses of the Assessment of Lescol in Renal Transplantation (ALERT) Study.

BACKGROUND: Renal transplantation is associated with an increased risk for premature cardiovascular disease. We analyzed the data in the placebo arm of Assessment of Lescol in Renal Transplantation (ALERT) to improve our understanding of the relationship between cardiovascular risk factors and outcomes in this unique population. METHODS: We performed Cox survival analysis for myocardial infarction, cardiac death, and noncardiac death in 1,052 patients recruited to the placebo arm of ALERT. These subjects were aged 30 to 75 years, had stable graft function at least 6 months after transplantation, had a serum total cholesterol level between 155 and 348 mg/dL (4 and 9 mmol/L), and were receiving cyclosporine-based immunosuppression. RESULTS: The results confirm previous studies. In multivariate analysis, preexisting coronary heart disease (hazard ratio [HR], 3.69; P < 0.001), total cholesterol level (HR, 1.55 per 50 mg/dL; P = 0.0045), and prior acute rejection (HR, 2.36; P = 0.0023) were independent risk factors. Conversely, independent risk factors for cardiac death were age (HR, 1.58 per decade; P = 0.0033), diabetes (HR, 3.35; P = 0.0002), ST-T changes on the ECG (HR, 3.17; P = 0.0004), and serum creatinine level (HR, 2.65 per milligram per deciliter; P < 0.0001). CONCLUSION: This analysis confirms that renal transplant recipients share risk factors for myocardial infarction and cardiac death with the general population. However, the pattern of risk factors and their relationship with outcomes is atypical, highlighting the unique nature of cardiovascular risk in transplant recipients.

Adult↗
PubMed2005

Secondary effects of immunosuppressive drugs after simultaneous pancreas-kidney transplantation.

BACKGROUND: This report examines the early and late secondary effects of tacrolimus, cyclosporin microemulsion (ME), mycophenolate mofetil (MMF) and rabbit anti-thymocyte globulin (rATG) in simultaneous pancreas-kidney (SPK) recipients. METHODS: Of the 205 patients participating in the Euro-SPK 001 study, 103 were randomized to tacrolimus (0.2 mg/kg) and 102 to cyclosporin-ME (7 mg/kg). All patients received rATG for 4 days [ATG-Fresenius (ATG-F) 4 mg/kg/day or Thymoglobulin (Thymo-S) 1.25 mg/kg/day] plus MMF and short-term corticosteroids. RESULTS: Thymo-S induction therapy was associated with a lower white cell count in the first 3 months than was seen with ATG-F, while ATG-F caused a lower initial nadir in platelet count. Both polyclonal preparations were well tolerated and no clinically relevant differences were observed with respect to side effects such as infections and malignancies. High cyclosporin-ME trough levels were associated with pancreas graft thrombosis, and concentrations >150 ng/ml were associated with poor renal allograft function. Treatment discontinuation was higher with cyclosporin-ME (57.8%) than with tacrolimus-based therapy (36.9%) due to more frequent toxicity, graft loss and lack of efficacy requiring a switch to tacrolimus. The main reason for withdrawal in the tacrolimus group was MMF discontinuation; MMF-related side effects resulted in more frequent dose reductions to <2 g/day and discontinuations in the tacrolimus group, and indirectly indicate a higher dose-corrected exposure to mycophenolic acid, as previously observed in kidney transplant patients. CONCLUSIONS: Short-term induction therapy is effective and well tolerated in patients undergoing SPK transplantation. Tacrolimus was the preferred immunosuppressive agent, resulting in fewer cases of pancreas graft loss and drug discontinuation compared with cyclosporin-ME.

Antilymphocyte Serum↗
PubMed2005

Nonadherence with diet and fluid restrictions among adults having hemodialysis.

PURPOSE: To describe the prevalence of nonadherence with the prescribed diet and fluid restrictions among patients receiving hemodialysis. METHODS: A multicenter cross-sectional design with 916 patients recruited from 18 dialysis centers in Germany and Belgium. The Dialysis Diet and Fluid Nonadherence Questionnaire (DDFQ) was used to measure patients' nonadherence. FINDINGS: The results showed that many patients had difficulty following diet (81.4%) and fluid (74.6%) restrictions. Younger male patients and smokers were at highest risk for non-adherence. Higher levels of interdialysis weight gain were associated with nonadherence. CONCLUSIONS: The findings indicate the need to continue to monitor and study hemodialysis patients' adherence behavior longitudinally and to design interventions to enhance adherence.

Adult↗
PubMed2005

Cytochrome P450 3A4 and P-glycoprotein activity and assimilation of tacrolimus in transplant patients with persistent diarrhea.

Renal transplant recipients suffering from persistent diarrhea have been repeatedly reported to have increased tacrolimus (Tac) trough levels. This study aimed to explore this phenomenon in detail in 15 renal transplant recipients with diarrhea, whose immunosuppression consisted of corticosteroids, mofetil mycophenolate and Tac. Both hepatic and intestinal CYP3A4 and PGP activity, important determinants of Tac bioavailability, were assessed, together with global CYP activity and investigations for gastrointestinal infection, function and morphology. Global CYP, CYP3A4, PGP and trough/dose levels of Tac were compared with diarrhea-free controls. In addition, a pharmacokinetic study of Tac was performed in 11 patients affected by diarrhea versus 9 controls. As expected, diarrhea was associated with increased Tac trough levels. An even stronger, significant increase of dose-normalized Tac levels was observed between 90 and 360 min after Tac intake. Time to peak concentration and drug half-life, however, were not altered. In addition, a concomitant decrease (+/-50%) of intestinal PGP activity was noticed in patients with diarrhea. For global CYP, CYP3A4 and hepatic PGP activity no such differences were noted. This pattern was not influenced by the specific cause of diarrhea. These data strongly suggest that persistent diarrhea is associated with an increased oral bioavailability of Tac.

ATP Binding Cassette Transporter, Subfamily B, Mem↗