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Kevork M Peltekian

Publications and source records attributed to Kevork M Peltekian.

11 recordsLinked to original sources
PubMed2006

Poor prediction of the glomerular filtration rate using current formulas in de novo liver transplant patients.

The utility of formulas estimating glomerular filtration rate (GFR) in liver transplant patients has not been well described. The purpose is to determine the correlation between the radionuclide GFR (rGFR) with formulas commonly used to estimate GFR. This study represented a secondary outcome measure of a multicenter randomized trial comparing the effectiveness of two immunosuppressive regimens in adult liver transplant patients (n=148). A total of 68 rGFR were measured, 33 at baseline and at 35 at three months after transplantation. GFR was estimated using 1/Scr and Cockcroft-Gault, MDRD, and Nankivell equations. At both time points assessed, all correlations with rGFR were poor: 1/Scr (r: 0.17 and 0.25), Cockcroft-Gault (r: 0.31 and 0.35), MDRD (r: 0.27 and 0.35), and Nankivell (r: 0.11 and 0.20). Accepted formulas to estimate GFR correlate poorly with rGFR during the first three months after liver transplantation. Recalibration of these formulas is required to improve the estimation of GFR in liver transplant patients.

Canada↗
PubMed2006

Recurrent hepatitis C post-transplantation: where are we now and where do we go from here? A report from the Canadian transplant hepatology workshop.

Approximately 400 liver transplants are performed in Canada every year and close to 6000 per year in the United States. Forty per cent to 45% of all liver transplants are performed for patients with underlying hepatitis C virus (HCV)-related liver disease. These patients have a different natural history, new complication risks and different treatment efficacy than nontransplant HCV patients. Every effort must be made to identify those patients at highest risk for progressive liver disease post-transplant. Recurrent HCV is an Achilles' heel to transplant hepatology. The true natural history of this disease is only starting to unravel and many questions remain unanswered on the optimal management of these patients after liver transplantation. The present report summarizes the literature and ongoing research needs that are specific to HCV-related liver transplantation.

Canada↗
PubMed2006

Serum creatinine in patients with advanced liver disease is of limited value for identification of moderate renal dysfunction: are the equations for estimating renal function better?

BACKGROUND: The Cockcroft-Gault formula (CGF) is used to estimate the glomerular filtration rate (GFR) based on serum creatinine (Cr) levels, age and sex. A new formula developed by the Modification of Diet in Renal Disease (MDRD) Study Group, based on the patient's Cr levels, age, sex, race and serum urea nitrogen and serum albumin levels, has shown to be more accurate. However, the best formula to identify patients with advanced liver disease (ALD) and moderate renal dysfunction (GFR 60 mL/min/1.73 m2 or less) is not known. The aim of the present study was to compare calculations of GFR, using published formulas (excluding those requiring urine collections) with standard radionuclide measurement of GFR in patients with ALD. METHODS: Fifty-seven consecutive subjects (40% women) with a mean age of 50 years (range 16 to 67 years) underwent 99m-technetium-diethylenetriamine pentaacetic acid (99mTc-DTPA) (single injection) radionuclide measurement of GFR. To calculate GFR, three formulas were used: the reciprocal of Cr multiplied by 100 (100/Cr), the CGF and the MDRD formulas. Pearson's correlation coefficient (r) and Bland-Altman analyses of agreement were used to analyze the association between 99mTc-DTPA clearance and the three equations for GFR. RESULTS: The mean 99mTc-DTPA clearance was 83 mL/min/1.73 m2 (range 28 mL/min/1.73 m2 to 173 mL/min/1.73 m2). Mean calculated GFRs by 100/Cr, the CGF and the MDRD formula were 106 mL/min/1.73 m2, 98 mL/min/1.73 m2 and 86 mL/min/1.73 m2, respectively. Regression analysis showed good correlation between radionuclide GFR and calculated GFR with r(100/Cr)=0.74, r(CGF)=0.80, r(MDRD)=0.87, all at P > or = 0.0001. The MDRD formula provided the least bias. The Bland-Altman plot showed best agreement between GFR calculated by the MDRD formula and 99mTc-DTPA clearance, with only 3 mL/min/1.73 m2 overestimation. There was higher variability between radionuclide GFR and calculated GFR by the CGF and by 100/Cr. Although there was no difference in precision, GFR calculated by the MDRD formula had the best overall accuracy. The sensitivity and specificity for detection of moderate renal dysfunction by the MDRD formulas were 73% and 87%, respectively. CONCLUSIONS: Among the Cr-based GFR formulas, the MDRD formula showed a larger proportion of agreement with radionuclide GFR in patients with ALD. In clinical practice, the MDRD is the best formula for detection of moderate renal dysfunction among those with ALD.

Adolescent↗
PubMed2005

Evaluation of renal function in liver transplant recipients receiving daclizumab (Zenapax), mycophenolate mofetil, and a delayed, low-dose tacrolimus regimen vs. a standard-dose tacrolimus and mycophenolate mofetil regimen: a multicenter randomized clinical trial.

Posttransplant chronic renal failure, secondary to calcineurin inhibitor agents, is emerging as a major problem in liver transplantation. We report a randomized clinical trial comparing daclizumab, delayed low-dose tacrolimus (target trough level 4-8 ng/mL, starting day 4-6), Investigational Arm (n = 72), to standard tacrolimus induction/maintenance dosing, Standard Arm (n = 76), with mycophenolate mofetil and tapering corticosteroids in both study arms. The end-points were renal function indicated by the Modification of Diet in Renal Disease (MDRD). There was no significant difference in patient survival (86.6% Investigational Arm vs. 92.9% Standard Arm; P = 0.21) or acute rejection (23.2% vs. 27.7%, respectively; P = 0.68). Statistically significant differences in median glomerular filtration rate (GFR) were found in favor of the Investigational Arm. With the CG equation, the GFR at the end of the first week was 110.7 vs. 89.6 mL/min (P = 0.019) without significant differences thereafter. With the MDRD, statistically significant differences extended to the first posttransplant month (86.8 vs. 70.1 mL/min/1.73 m(2); P < 0.001) with and was seen at month 6 (75.4 vs. 69.5 mL/min/1.73 m(2); P = 0.038). In conclusion, delayed low-dose tacrolimus, in combination with daclizumab and mycophenolate mofetil, preserves early renal function post-liver transplantation without the cost of increased acute rejection.

Antibodies, Monoclonal↗
PubMed2004

Utility of MELD and Child-Turcotte-Pugh scores and the Canadian waitlisting algorithm in predicting short-term survival after liver transplant.

BACKGROUND: The Model for End-Stage Liver Disease (MELD) and Child-Turcotte-Pugh (CTP) scores are important predictors for survival after liver transplantation (LT). The objective of this study was to compare the utility of MELD and CTP scores with Canadian waitlisting algorithm in transplantation (CanWAIT) status for predicting 90-day survival after LT. METHODS: Retrospectively, we analyzed all 228 liver transplants performed in adults by the Atlantic Liver Transplant Program since 1985. These cases included combined transplants, retransplants and those after fulminant liver failure. MELD and CTP scores were calculated, and CanWAIT status and waiting time on the day of LT determined. We used c-statistic for 90-day outcome as the endpoint (survival), comparing areas under the receiver operating characteristic (ROC) curves for MELD and CTP scores and CanWAIT status. RESULTS: Mean (and standard deviation [SD]) MELD score was 18 (SD 12); CTP score, 10 (SD 3); and waiting time, 97 (SD 132) days. At the time of LT, 54% were in CanWAIT status 1; 4% in 1T; 14% in 2; 11% in 3; 6% in 3F; 4% in 4; and 7% in status 4F. Overall 90-day survival was 80% (95% confidence interval [CI] 75%-85%), exceeding the predicted survival by MELD scale with transplant of only 51% (CI 47%-55%). By c-statistic, CanWAIT is a clinically relevant predictor of 90-day outcomes in LT. By multivariate regression analysis, only CanWAIT status and age were found to have independent associations for short-term outcomes after LT. INTERPRETATION: CanWAIT status stratifies LT patients better and predicts short-term outcome more accurately than MELD or CTP scores, and so should not be replaced by MELD or CTP scores. This observation should be confirmed by a prospective and multicentre study in Canada.

Adult↗
PubMed2002

A clinical pharmacokinetic study of tacrolimus and sirolimus combination immunosuppression comparing simultaneous to separated administration.

The pharmacokinetic (PK) interaction between tacrolimus (TAC) and sirolimus (SRL), similarly structured immunosuppressive compounds that share binding proteins, is unknown. The combination of SRL with cyclosporin (CsA) has been studied, and a 4-hour interval between dosing of the two drugs is recommended even though it is inconvenient for patients and may affect compliance. Twenty-five liver and kidney-pancreas transplant recipients treated with a combination of SRL and low-dose TAC completed full PK studies while being treated with 4-hour interval dosing (ID) and then with simultaneous dosing. Whole blood was sampled for immunoassay measurement of TAC and SRL levels. Blood concentration/dose ratios of SRL and TAC varied between patients by a factor of 8 and 5, respectively, but correlation between trough concentration levels (C(0)) and drug exposure area under the concentration-time curve (AUC) was excellent (TAC: r(2) = 0.82; SRL: r(2) = 0.83). Neither PK profiles of SRL nor those of TAC were altered by simultaneous administration. Dose-corrected AUC and C0 of TAC correlated with SRL (r(2) = 0.8 and 0.8, respectively). Bone marrow suppression and nephrotoxicity were not enhanced nor were any new toxicities observed when TAC and SRL were used in combination. These data confirm that simultaneous dosing of TAC and SRL after transplantation is safe and that trough level monitoring is adequate to control therapy.

Adult↗
PubMedDate not supplied

Choroidal neovascularization with interferon associated retinopathy: case report and review of literature.

We report a case of new interferon-associated ocular complication during treatment with combination of pegylated interferon plus ribavirin for chronic hepatitis C infection. Our patient developed choroidal neovascularization in addition to the classic interferon associated retinopathy. Choroidal neovascularization has not been reported before in association with interferon induced retinopathy. We describe our management to control the ocular symptoms and the retinal lesions with one year follow up. We also provide literature report on the natural history, the pathophysiology and the variable characteristics of interferon associated retinopathy versus hepatitis C related ophthalmopathy.

Adult↗