Ulatory and free of intercurrent illness. None of the patients showed signs for acute rejection of kidney allograft. Patient’s history was raised by trained personal using medical records and a standardized questionnaire and comprised personal history and previous history of renal disease and cardiovascular disease. None of the patients had severe tachycardia or bradycardia, which may affect Doppler measurements. Blood pressure was obtained by conventional sphygmomanometric methods on three occasions in a sitting position after a rest of 10 minutes. Phases I and V of the Korotkoff sounds were considered as systolic blood pressure and diastolic blood pressure, respectively. A glomerular filtration rate less than 30 mL/min/1.73 m2 indicated chronic kidney disease stage 4 or higher. Glomerular filtration rate was calculated according to the chronic kidney disease epidemiology collaboration (CKD-EPI) equation [8]. As indicated by Levey et al., variables included in the CKD-EPI equation for estimating log glomerular filtration rate are log serum creatinine (modeled as a two-slope linear spline with sex-specific knots at 62 mmol/L (0.7 mg/dL) in women and 80 mmol/L (0.9 mg/dL) in men), sex, race and age on the natural scale, compared to log serum creatinine without a spline, sex, race and age on the log scale in the MDRD Study equation [8]. In transplant recipients with chronic kidney disease this CKD-EPI formula showed better results than other formulas to estimate glomerular filtration rate [9]. None of the patients with renal allograft was at dialysis treatment at the time of the study.patients with a renal arterial NT 157 site resistive-index less than 0.66 the intraobserver intrasession variability was 1 (95 limits of agreement, 220 to 22 ), whereas in patients with a renal arterial resistive-index higher than 0.66 it was 5 (95 limits of agreement, 214 to 23 ). None of the patients had hydronephrosis of grade 2 or higher.StatisticsContinuous data are presented as median and interquartile range. Non-parametric Mann-Whitney test was used to detect differences in continuous variables between the groups. Frequency counts were calculated for categorical data such as gender, specific medications, and diagnostic classifications. Differences in these categorical variables between the groups were analyzed by Fisher’s exact test. The product limit method of Kaplan and Meier was used to show the fraction of patients presenting with chronic kidney disease stage 4 or higher according to renal arterial resistive index. Curves were compared using the logrank test. Logistic MNS regression analysis was used to determine those variables independently associated with chronic kidney disease stage 4 or higher. The variables tested were renal arterial resistive index, age of renal allograft recipient, time since transplantation, systolic blood pressure, diastolic blood pressure, and pulse pressure. For multivariate analysis, the effect of multiple variables on the presence of chronic kidney disease stage 4 or higher was evaluated in 78 patients with stepwise forward regression analysis (with p = 0.10 as the threshold level of significance for the removal of the variable from analysis and p = 0.05 as the threshold for entry into the model). Data were analyzed using GraphPad prism software (version 5.0, GraphPad Software, San Diego, CA, USA) and SPSS for windows (version 15.0; SPSS, Chicago, IL, USA). All statistical tests were two-sided. Two-sided p-values less than 0.05.Ulatory and free of intercurrent illness. None of the patients showed signs for acute rejection of kidney allograft. Patient’s history was raised by trained personal using medical records and a standardized questionnaire and comprised personal history and previous history of renal disease and cardiovascular disease. None of the patients had severe tachycardia or bradycardia, which may affect Doppler measurements. Blood pressure was obtained by conventional sphygmomanometric methods on three occasions in a sitting position after a rest of 10 minutes. Phases I and V of the Korotkoff sounds were considered as systolic blood pressure and diastolic blood pressure, respectively. A glomerular filtration rate less than 30 mL/min/1.73 m2 indicated chronic kidney disease stage 4 or higher. Glomerular filtration rate was calculated according to the chronic kidney disease epidemiology collaboration (CKD-EPI) equation [8]. As indicated by Levey et al., variables included in the CKD-EPI equation for estimating log glomerular filtration rate are log serum creatinine (modeled as a two-slope linear spline with sex-specific knots at 62 mmol/L (0.7 mg/dL) in women and 80 mmol/L (0.9 mg/dL) in men), sex, race and age on the natural scale, compared to log serum creatinine without a spline, sex, race and age on the log scale in the MDRD Study equation [8]. In transplant recipients with chronic kidney disease this CKD-EPI formula showed better results than other formulas to estimate glomerular filtration rate [9]. None of the patients with renal allograft was at dialysis treatment at the time of the study.patients with a renal arterial resistive-index less than 0.66 the intraobserver intrasession variability was 1 (95 limits of agreement, 220 to 22 ), whereas in patients with a renal arterial resistive-index higher than 0.66 it was 5 (95 limits of agreement, 214 to 23 ). None of the patients had hydronephrosis of grade 2 or higher.StatisticsContinuous data are presented as median and interquartile range. Non-parametric Mann-Whitney test was used to detect differences in continuous variables between the groups. Frequency counts were calculated for categorical data such as gender, specific medications, and diagnostic classifications. Differences in these categorical variables between the groups were analyzed by Fisher’s exact test. The product limit method of Kaplan and Meier was used to show the fraction of patients presenting with chronic kidney disease stage 4 or higher according to renal arterial resistive index. Curves were compared using the logrank test. Logistic regression analysis was used to determine those variables independently associated with chronic kidney disease stage 4 or higher. The variables tested were renal arterial resistive index, age of renal allograft recipient, time since transplantation, systolic blood pressure, diastolic blood pressure, and pulse pressure. For multivariate analysis, the effect of multiple variables on the presence of chronic kidney disease stage 4 or higher was evaluated in 78 patients with stepwise forward regression analysis (with p = 0.10 as the threshold level of significance for the removal of the variable from analysis and p = 0.05 as the threshold for entry into the model). Data were analyzed using GraphPad prism software (version 5.0, GraphPad Software, San Diego, CA, USA) and SPSS for windows (version 15.0; SPSS, Chicago, IL, USA). All statistical tests were two-sided. Two-sided p-values less than 0.05.