Radionuclide Glomerular Filtration Rate Research Articles

Pretransplant Use of the Chronic Kidney Disease Epidemiology Collaboration Equation (CKD-EPI) to Estimate Glomerular Filtration Rate Predicts Outcomes in Liver Transplant Recipients.

Kidney dysfunction is common in liver transplant candidates and is a well-established predictor of increased mortality after liver transplant. However, the best method for determination of the glomerular filtration rate before liver transplant remains unclear. We analyzed the performance of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and the Modification of Diet in Renal Disease (MDRD) Study equation, before liver transplant, compared with radionuclide glomerular filtration rate and examined the association of the 2 equations with a composite outcome of stage 4 chronic kidney disease, initiation of chronic dialysis, or patient death. We studied 426 consecutive adult liver transplant recipients from 1990 to 2014. The correlation coefficient of the radionuclide glomerular filtration rate with the Chronic Kidney Disease Epidemiology Collaboration equation was 0.61 and with the Modification of Diet in Renal Disease Study equation was 0.58. The Modification of Diet in Renal Disease Study equation showed a bias of -4.7 mL/min and precision of 32.9 mL/min, whereas the Chronic Kidney Disease Epidemiology Collaboration equation showed a bias of -11.1 mL/min but was more precise (28.1 mL/min). Only the Chronic Kidney Disease Epidemiology Collaboration equation remained significantly associated with the composite outcome in the multivariable analysis. The use of the Chronic Kidney Disease Epidemiology Collaboration equation in the period before liver transplant provided independent prognostic information regarding long-term outcomes after liver transplant.

The Chronic Kidney Disease Epidemiology Collaboration (CKDEPI) equation best characterizes kidney function in patients being considered for lung transplantation

Methods for direct measurement of glomerular filtration rate (GFR) are expensive and inconsistently applied across transplant centers. The Modified Diet in Renal Disease (MDRD) equation is commonly used for GFR estimation, but is inaccurate for GFRs >60 ml/min per 1.73 m(2). The Chronic Kidney Disease Epidemiology Collaboration (CKDEPI) and Wright equations have shown improved predictive capabilities in some patient populations. We compared these equations to determine which one correlates best with direct GFR measurement in lung transplant candidates. We conducted a retrospective cohort analysis of 274 lung transplant recipients. Pre-operative GFR was measured directly using a radionuclide GFR assay. Results from the MDRD, CKDEPI, Wright, and Cockroft-Gault equations were compared with direct measurement. Findings were validated using logistic regression models and receiver operating characteristic (ROC) analyses in looking at GFR as a predictor of mortality and renal function outcomes post-transplant. Assessed against the radionuclide GFR measurement, CKDEPI provided the most consistent results, with low values for bias (0.78), relative standard error (0.03) and mean absolute percentage error (15.02). Greater deviation from radionuclide GFR was observed for all other equations. Pearson's correlation between radionuclide and calculated GFR was significant for all equations. Regression and ROC analyses revealed equivalent utility of the radionuclide assay and GFR equations for predicting post-transplant acute kidney injury and chronic kidney disease (p < 0.05). In patients being evaluated for lung transplantation, CKDEPI correlates closely with direct radionuclide GFR measurement and equivalently predicts post-operative renal outcomes. Transplant centers could consider replacing or supplementing direct GFR measurement with less expensive, more convenient estimation by using the CKDEPI equation.

Overestimation of carboplatin doses is avoided by radionuclide GFR measurement

Background:Glomerular filtration rate (GFR) is used in the calculation of carboplatin dose. Glomerular filtration rate is measured using a radioisotope method (radionuclide GFR (rGFR)), however, estimation equations are available (estimated GFR (eGFR)). Our aim was to assess the accuracy of three eGFR equations and the subsequent carboplatin dose in an oncology population.Patients and methods:Patients referred for an rGFR over a 3-year period were selected; eGFR was calculated using the Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Cockcroft-Gault (CG) equations. Carboplatin doses were calculated for those patients who had received carboplatin chemotherapy. Bias, precision and accuracy were examined.Results:Two hundred and eighty-eight studies met the inclusion/exclusion criteria. Paired t-tests showed significant differences for all three equations between rGFR and eGFR with biases of 12.3 (MDRD), 13.6 (CKD-EPI) and 7.7 ml min−1 per 1.73 m2 (CG). An overestimation in carboplatin dose was seen in 81%, 87% and 66% of studies using the MDRD, CKD-EPI and CG equations, respectively.Conclusion:The MDRD and CKD-EPI equations performed poorly compared with the reference standard rGFR; the CG equation showed smaller bias and higher accuracy in our oncology population. On the basis of our results we recommend that the rGFR should be used for accurate carboplatin chemotherapy dosing and where unavailable the use of the CG equation is preferred.

Correlation of various published radionuclide glomerular filtration rate estimation techniques and proposed paediatric normative data

The aim of this study is to assess the comparability and interchangeability of the radionuclide glomerular filtration rate (GFR) using different published techniques, and propose normative data for paediatrics. A total of 476 paediatric oncology patients aged 2-17 years, referred between January 2001 and December 2008 for GFR estimation, were reviewed for any potential cause of renal impairment. Sixty-nine patients met the stringent inclusion criteria, and were included in the study. GFR estimation was carried out using either technetium-99m diethylene triamine penta-acetic acid (⁹⁹mTc-DTPA) or chromium-51 EDTA (⁵¹Cr-EDTA). Multiple GFR results were calculated from the same blood sample data (counts/min/ml), according to previously published GFR estimation techniques using one to three blood samples. These techniques were slope-intercept, slope-only and half life. For slope-intercept techniques, GFR was normalized to body surface area or extracellular fluid volume. The GFR values obtained using different techniques were highly variant. The intraclass correlation (ICC) for different methods was moderate (ICC=0.56-0.66). A reliable empiric formula to allow conversion of GFR values from one technique to another could not be derived because of this variability, with some exceptions. ⁵¹Cr-EDTA yielded the same or lower variability than ⁹⁹mTc-DTPA. The British Nuclear Medicine Society-recommended method had the lowest coefficient of variation, with a mean value of 116 (SD 22) normalized to 1.73 m² for ⁵¹Cr-EDTA using two samples. The GFR values obtained from different calculation techniques are not readily interchangeable or comparable, with some exceptions. For both ⁹⁹mTc-DTPA and ⁵¹Cr-EDTA, the British Nuclear Medicine Society-recommended technique appears to be the most robust, with the least coefficient of variation.

Very high GFR in cancer patients undergoing chemotherapy: prevalence, carboplatin dosing patterns and chemotherapy toxicity

Carboplatin dosing depends on accurate glomerular filtration rate (GFR) estimation. There is a lack of clinical agreement about carboplatin dosing when the GFR measurement is very high (>110 mL/min). A retrospective audit of pre-chemotherapy 99m technetium (Tc) diethylenetriamene pentaacetate (DTPA) radionuclide GFR estimations and patients' chart review were performed from January 2006 to May 2009. The primary objective was to determine the prevalence of patients with a high GFR and the incidence of myelotoxicity in this group. Overall 18 of 148 treated patients (14%) measured GFR >110mL/min. The GFR values of six of the 18 patients were capped for dose calculation. In eight patients a measured GFR corrected for body surface area was used and in four the actual measured GFR was used for dose calculation. In total, 63 cycles of chemotherapy were delivered. Grade III or IV myelotoxicity accounted for 37% (15/41) of all myelotoxicities. Neutropenia accounted for almost 39% of all myelotoxicities (16/41). Two patients (11%) were hospitalized due to febrile neutropenia. Eight patients (40%) had dose reduction and four (20%) had treatment delays due to myelotoxicity. The frequency of myelotoxicity was high irrespective of the GFR used (corrected or uncorrected) in calculating the chemotherapy dose. High values of GFR, by 99mTc DTPA radionuclide measurement, are a common finding in pre-chemotherapy patients irrespective of age. Carboplatin dosing patterns in this group of patients vary among treating oncologists and a standardized approach is needed.

Evaluation of Various Formulae for Glomerular Filtration Rate Estimation and Proposal of New Formulae for the Korean Population

Some researchers have questioned the necessity of adjusting glomerular filtration rate (GFR) by body surface area (BSA). We compared the relationship between estimated GFR (eGFR) and radionuclide GFR (rGFR) with or without BSA adjustment by comparing the results obtained using various formulae with those obtained using 2 new proposed formulae. A retrospective study was performed using 204 Korean individuals whose GFR had been estimated by the (99m)Tc-diethylenetriaminepentaacetic acid method between March 2004 and July 2008. We used the modification of diet in renal disease (MDRD) II formula, Mayo clinic quadratic (MCQ) formula, Cockcroft-Gault (CG) formula, and lean body mass-adjusted CG formula. Two new formulae, skeletal muscle mass index (SMI)-adjusted CG formula and SMI × 3.4/SCr, were proposed by us. We analyzed each parameter with Pearson's correlation coefficient and also obtained the bias values. BSA did not satisfy the fundamental prerequisites of an adjustment factor for rGFR. MDRD II and MCQ GFR estimates demonstrated higher Pearson's correlation coefficient with BSA-unadjusted rGFR than they did with BSA-adjusted rGFR. The other GFR formulae estimates showed better correlation with rGFR and more favorable bias (P<0.001) when both GFR estimates and rGFR values were BSA-unadjusted. SMI-adjusted CG and SMI × 3.4/SCr GFR estimates demonstrated correlation with rGFR and bias values similar to those of the MDRD II and CG GFR estimates. We suggest that absolute, non-corrected GFR and GFR estimate be preferred in daily practice. The absolute, non-corrected GFR and GFR estimate are considered helpful for patients with eGFR ≤ 60 mL/min/1.73 m(2). We also recommend the clinical use of the new formulae, SMI-adjusted CG and SMI × 3.4/SCr (BSA-unadjusted).

177Lu-octreotate, alone or with radiosensitising chemotherapy, is safe in neuroendocrine tumour patients previously treated with high-activity 111In-octreotide

The aim of this retrospective study was to determine whether patients with previous peptide receptor radionuclide therapy using high-activity (111)In-pentetreotide can be safely treated with (177)Lu-octreotate and whether addition of radiosensitising chemotherapy increases the toxicity of this agent. Records of 27 patients (aged 17-75) who received 69 (median 3 per patient) (177)Lu-octreotate administrations, including 29 in conjunction with radiosensitising infusional 5-fluorouracil (5-FU) (n = 27), or capecitabine (n = 2), between October 2005 and July 2007 subsequent to 1-8 prior cycles of (111)In-pentetreotide therapy were analysed. Toxicity was assessed during and at 8-12 weeks post-treatment, with further long-term assessments including survival status reviewed till death or study close-out date of 1 November 2009. Reduction in blood counts was most marked following the first dose of (177)Lu-octreotate but at early follow-up the only major haematological toxicity was a single case of grade 4 lymphopaenia. Both the presence of bone metastases and the administration of chemotherapy tended to result in greater reduction in blood counts, but these differences did not reach statistical significance. On long-term follow-up, 16 patients (59%) are alive with median overall survival of 36 months (32-44 months from first (177)Lu-octreotate therapy). None of the recorded deaths was directly related to treatment toxicity. One patient had late grade 4 anaemia and thrombocytopaenia secondary to bone marrow failure from progressive infiltration by tumour. No other significant long-term haematological toxicities were recorded and no leukaemia was observed. No renal toxicity was observed on serial serum creatinine or radionuclide glomerular filtration rate (GFR) determination on initial or long-term follow-up. (177)Lu-octreotate is a safe and well-tolerated therapy for patients who have previously been treated with (111)In-pentetreotide and can be safely combined with radiosensitising chemotherapy. However, caution is recommended in patients with bone metastases. Significant late toxicities including bone marrow or renal failure, or leukaemia directly related to radionuclide therapy, did not occur in our series.

Effect of B-Vitamin Therapy on Progression of Diabetic Nephropathy

Hyperhomocysteinemia is frequently observed in patients with diabetic nephropathy. B-vitamin therapy (folic acid, vitamin B(6), and vitamin B(12)) has been shown to lower the plasma concentration of homocysteine. To determine whether B-vitamin therapy can slow progression of diabetic nephropathy and prevent vascular complications. A multicenter, randomized, double-blind, placebo-controlled trial (Diabetic Intervention with Vitamins to Improve Nephropathy [DIVINe]) at 5 university medical centers in Canada conducted between May 2001 and July 2007 of 238 participants who had type 1 or 2 diabetes and a clinical diagnosis of diabetic nephropathy. Single tablet of B vitamins containing folic acid (2.5 mg/d), vitamin B(6) (25 mg/d), and vitamin B(12) (1 mg/d), or matching placebo. Change in radionuclide glomerular filtration rate (GFR) between baseline and 36 months. Secondary outcomes were dialysis and a composite of myocardial infarction, stroke, revascularization, and all-cause mortality. Plasma total homocysteine was also measured. The mean (SD) follow-up during the trial was 31.9 (14.4) months. At 36 months, radionuclide GFR decreased by a mean (SE) of 16.5 (1.7) mL/min/1.73 m(2) in the B-vitamin group compared with 10.7 (1.7) mL/min/1.73 m(2) in the placebo group (mean difference, -5.8; 95% confidence interval [CI], -10.6 to -1.1; P = .02). There was no difference in requirement of dialysis (hazard ratio [HR], 1.1; 95% CI, 0.4-2.6; P = .88). The composite outcome occurred more often in the B-vitamin group (HR, 2.0; 95% CI, 1.0-4.0; P = .04). Plasma total homocysteine decreased by a mean (SE) of 2.2 (0.4) micromol/L at 36 months in the B-vitamin group compared with a mean (SE) increase of 2.6 (0.4) micromol/L in the placebo group (mean difference, -4.8; 95% CI, -6.1 to -3.7; P < .001, in favor of B vitamins). Among patients with diabetic nephropathy, high doses of B vitamins compared with placebo resulted in a greater decrease in GFR and an increase in vascular events. isrctn.org Identifier: ISRCTN41332305.

Comparison of the Mayo Clinic Quadratic Equation with the Modification of Diet in Renal Disease equation and radionuclide glomerular filtration rate in a clinical setting

Recent guidelines recommend automatic reporting of estimated glomerular filtration rate (eGFR) using the abbreviated Modification of Diet in Renal Disease (MDRD) equation with every request for plasma creatinine. The Mayo Clinic Quadratic Equation (MCQE) has been put forwards as a potentially more accurate alternative. We therefore evaluated its accuracy compared with radionuclide GFR in a clinical setting. Data were collected on 601 patients aged 16-85 years who had undergone radionuclide GFR, and eGFR was calculated using MCQE and MDRD. Calculations of bias, correlation coefficients and percentage estimates within 30% and 50% of radionuclide GFR were used in comparisons. The MCQE had a significant positive bias in the overall population but no significant bias in individuals with normal renal function defined as measured GFR > 90 mL/min per 1.73 m(2). There was no significant difference in the performance of MCQE and MDRD eGFR in patients with measured GFR > 90 mL/min per 1.73 m(2). However, in the overall group and in subjects with radionuclide GFR < 90 mL/min per 1.73 m(2), the accuracy of MDRD eGFR with respect to the proportion of patients within 30% and 50% of radionuclide GFR was better than MCQE. MCQE compared moderately well with radionuclide GFR, although its overall bias and accuracy were inferior when compared with the MDRD equation in a clinical setting.

Predicting Glomerular Filtration Rate in Heart Transplant Recipients Using Serum Creatinine–based Equations With Cimetidine

In this study we evaluated the use of cimetidine on the performance of glomerular filtration rate (GFR) estimating equations and 24-hour creatinine clearance (24-hour CrCl) against radionuclide GFR in 43 heart transplant recipients with stable renal function. Pearson correlation coefficients for the 24-hour CrCl, Cockcroft-Gault, Nankivell and Modification of Diet in Renal Disease study (MDRD) equations without cimetidine were 0.76, 0.70, 0.81 and 0.76, and cimetidine-aided coefficients were 0.82, 0.80, 0.80 and 0.72, respectively. All the tested equations without cimetidine use predicted GFR with moderate accuracy in this population. The addition of cimetidine improved the predictive ability of the 24-hour CrCl and Cockcroft-Gault formulas, but not the Nankivell and MDRD GFR estimating equations, in heart transplant recipients.

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.

Comparison of two prediction equations with radionuclide glomerular filtration rate: validation in routine use

Recent guidelines recommend automatic reporting of estimated glomerular filtration rate (eGFR) using the abbreviated Modification of Diet in Renal Disease (MDRD) equation with every request for plasma creatinine. We evaluated the performance of the MDRD and Cockcroft-Gault equations in routine use compared with a radionuclide GFR method. Data collected on 601 patients aged 16-85 years who had undergone radionuclide GFR and eGFR was calculated using both equations for each patient. Calculations of bias, correlation coefficients and percentage estimates within 30% and 50% of radionuclide GFR were used in comparisons. Overall, there was no significant difference in the performance between the two equations when compared with radionuclide GFR. When all creatinine results <60 micromol/L were adjusted to 60 micromol/L, and when creatinine results <60 micromol/L were excluded, MDRD performed better than the Cockcroft-Gault equation. MDRD was also superior for prediction of radionuclide GFR of <60 mL/min/1.73 m(2) (P=0.014). The abbreviated MDRD formula for eGFR is superior to the Cockcroft-Gault equation for prediction of radionuclide GFR of <60 microL/min/1.73 m(2)and is more accurate when creatinine results <60 micromol/L are either corrected to 60 micromol/L or excluded from eGFR calculations.

Lean body mass‐adjusted Cockcroft and Gault formula improves the estimation of glomerular filtration rate in subjects with normal‐range serum creatinine

Assessment of glomerular filtration rate (GFR) in individuals with normal-range serum creatinine is important in certain clinical situations, such as in potential living kidney donors. Accurate measurements of GFR invariably involve using an invasive method (e.g. inulin clearances), but is inconvenient. The aim of the present study was to determine whether serum creatinine-based prediction formulae adjusted for lean body mass (LBM) could improve the accuracy of GFR estimation in these subjects. Glomerular filtration rate was determined by the clearance of technetium-99m-labelled diethylenetriamine penta-acetic acid ((99m)Tc DTPA) from plasma in 56 subjects with normal serum creatinine. For each subject, GFR was estimated using prediction formulae +/- LBM adjustment and compared with measured GFR. Formulae analysed include Cockcroft-Gault, Levey, Gates, Mawer, Hull, Toto, Jellife and Bjornsson. All formulae +/- LBM adjustment underestimated measured GFR, with poor precision, poor agreement and correlation (r (2) <or= 0.25). Between 69% and 95% of the estimated GFR determined by the formulae correctly classified those with a normal measured GFR. LBM-adjusted formulae significantly improved the accuracy of GFR estimation compared with unadjusted formulae. The lean body mass-adjusted Cockcroft-Gault formula was the closest to measured GFR but is not accurate enough to replace radionuclide GFR measurement. Prediction formulae should be adjusted for LBM to improve GFR estimation.

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?

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. 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. 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. 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.

ACCURACY OF CIMETIDINE-CORRECTED SERUM CREATININE, CREATININE CLEARANCE AND CALCULATED CREATININE CLEARANCE TO ASSESS THE GLOMERULAR FILTRATION RATE IN LONG-TERM KIDNEY-PANCREAS AND LIVER TRANSPLANT PATIENTS

P863 Serum creatinine (Scr) and the endogenous creatinine clearance (CrCl) overestimate the glomerular filtration rate (GFR). Cimetidine decreases the tubular secretion of creatinine and improves the accuracy of the CrCl and calculated (Calc) CrCl (based on the Cockroft-Gault formula), in pts with various renal diseases. Aim: To determine the effect of cimetidine on renal function markers (Scr, CrCl and the CalcCrCl) and to correlate these markers with the radionuclide GFR in long-term recipients of kidney/pancreas (KP) Tx and liver (L) Tx. Methods: We enrolled 18 pts (5 women, 13 men, 46±8 yrs), who were >1 yr (28±20 mo.) post-KPTx and 38 pts (14 women, 24 men, 61±11 yrs), who were >1-yr (57±34 mo.) post-LTx. All the pts were on a calcineurin inhibitor. All the pts received cimetidine 800 mg t.i.d for 1 day and collected urine (24-hr) during the same day, the day before the annual radionuclide GFR. Scr, CrCl and the CalcCrCl (cimetidine-corrected) were measured on the day of the annual GFR. Results: LTx pts were older (P<0.0001). Cimetidine was well tolerated and no side-effects were observed. The cost of 2,400 mg of cimetidine was lower than the cost of the radionuclide GFR (CDN $0.48 vs. $66.00). Table 1. Effect of Cimetidine on renal function markersFigureTable 2. Correlation (r2) between the GFR and cimetidine-corrected markers of renal functionFigureaP = 0.006, bP = 0.0003, cP < 0.0001, dP = 0.0007, cP = 0.034 Conclusion: Renal function markers are overestimated in long-term recipients of KPTx and LTx. Our results suggest that cimetidine improves the accuracy of CrCl and CalcCrCl to assess the GFR in KPTx pts. The cimetidine-corrected CalcCrCl, may become a cost-effective alternative to assess the GFR in these pts. In LTx pts, cimetidine-corrected Scr appears to correlate better with the GFR compared to the cimetidine-corrected CrCl and CalcCrCl. A modified CalcCrCl formula needs to be developed to assess the GFR in LTx pts.

Correlation between serum creatinine, creatinine clearance, the calculated creatinine clearance and the glomerular filtration rate in heart transplant patients

Assessment of glomerular filtration rate (GFR) in heart transplant (HTx) patients is based on serum creatinine (sCr), the endogenous creatinine clearance (C Cr) and radionuclide GFR (rGFR); however, the latter is expensive and time consuming. We reviewed the data of 32 adult HTx patients to determine the correlation between sCr, C Cr, the calculated C Cr (Calc.C Cr; based on gender, age, weight and sCr) and rGFR in long-term (>1 year) HTx patients receiving calcineurin inhibitors. The Calc.C Cr was found to have the best correlation with rGFR ( r 2 = 0.65), followed by C Cr ( r 2 = 0.53) and sCr ( r 2 = 0.38). The use of Calc.C Cr to estimate GFR may be cost-effective in assessing renal function after HTx.