the question of structural and mechanical alterations of the arterial wall in the case of renal transplantation has not yet been completely resolved . an insufficiency of endogenous regulators of calcium and phosphate is well known to be a significant factor affecting extraosseous calcifications.1 in dialysis patients and kidney transplant patients , volume overload and disturbances of calcium and phosphate metabolism add to the atherogenic profile , and these serve as independent risk factors for cardiovascular mortality.2 the presence of arterial calcifications was strongly and independently predictive of the outcome in end - stage renal disease ( esrd).3 on this basis , estimating the arterial stiffness ( as ) in esrd is of great interest . measuring the pulse - wave velocity ( pwv ) is a reliable means of determining the as.4,5 there are several studies of pwv in patients with renal transplantation.69 notably , 24-hour pwv analysis has not yet been conducted in adults . meanwhile , some modern devices for ambulatory blood pressure monitoring ( abpm ) allow the assessment of some as indices , and the approach to the analysis of these indices may be quite similar to that of abpm.10 accordingly , the aim of our study was to assess the feasibility of this approach in the management of patients with renal transplantation . overall , 41 patients were recruited from the kidney transplant waiting list of the privolzhsky district medical center in nizhniy novgorod , russia . the inclusion criteria were the following : age between 18 years and 55 years , esrd resulting from nondiabetic glomerulopathy ( glomerular filtration rate < 15 ml / min per 1.73 m ) , and candidate for a first kidney transplant . patients with a history of prior kidney transplant or who were candidates for a kidney - pancreas transplant were excluded from the study . the additional exclusion criteria were cardiac rhythm disturbances , body mass index higher than 35 kg / m , severe dyslipidemia , and unstable clinical presentation . our study group included 27 ( 65.8% ) men and had a mean age of 35.2 years , with a mean systolic blood pressure of 134 mmhg , mean diastolic blood pressure of 86 mmhg , and mean heart rate of 74 beats per minute . all the patients were receiving dialysis at enrollment , including 40 by hemodialysis and one by peritoneal dialysis . management of patients included the monitoring of calcium and phosphate serum levels and their correction . all measurements were performed before kidney transplantation and at 1 and 20 weeks after transplantation . approval for the study was obtained from the local research ethics committee , and written informed consent was obtained for each participant . the vasotens technology is an innovative method used for pulse - wave analysis based on oscillometric blood pressure measurements , using the bplab ( nizhniy novgorod , russia ) device for abpm.11,12 the technology was developed by the petr telegin company in nizhniy novgorod , russia . the recordings are made using a conventional blood pressure cuff for adults . during the blood pressure measurement , the pressure waveforms in the cuff are registered while performing a step - by - step deflation . the separation and timing of the forward and reflected pulse waves are determined by a special mathematical algorithm . the distance for the pwv equation used by the vasotens was measured according to the bplab user s guide requirements . the quality control method consists of a visual assessment of the curves in the vasotens clinical report screen . the pulse time index of norm ( ptin ) is calculated by the vasotens for the estimation of the 24-hour pwv . the principle of the ptin calculation is where tm is the entire period of monitoring and t1 , t2 , and tn represent the periods in which the pwv does not exceed the cut - off value of 10 m / second . essentially , all the data are shown as the mean and standard deviation ( sd ) . we used bpstat software , version 05.00.04 ( bplab ) to tabulate all the indices of every measured 24-hour waveform automatically . overall , 41 patients were recruited from the kidney transplant waiting list of the privolzhsky district medical center in nizhniy novgorod , russia . the inclusion criteria were the following : age between 18 years and 55 years , esrd resulting from nondiabetic glomerulopathy ( glomerular filtration rate < 15 ml / min per 1.73 m ) , and candidate for a first kidney transplant . patients with a history of prior kidney transplant or who were candidates for a kidney - pancreas transplant were excluded from the study . the additional exclusion criteria were cardiac rhythm disturbances , body mass index higher than 35 kg / m , severe dyslipidemia , and unstable clinical presentation . our study group included 27 ( 65.8% ) men and had a mean age of 35.2 years , with a mean systolic blood pressure of 134 mmhg , mean diastolic blood pressure of 86 mmhg , and mean heart rate of 74 beats per minute . all the patients were receiving dialysis at enrollment , including 40 by hemodialysis and one by peritoneal dialysis . management of patients included the monitoring of calcium and phosphate serum levels and their correction . all measurements were performed before kidney transplantation and at 1 and 20 weeks after transplantation . approval for the study was obtained from the local research ethics committee , and written informed consent was obtained for each participant . the vasotens technology is an innovative method used for pulse - wave analysis based on oscillometric blood pressure measurements , using the bplab ( nizhniy novgorod , russia ) device for abpm.11,12 the technology was developed by the petr telegin company in nizhniy novgorod , russia . the recordings are made using a conventional blood pressure cuff for adults . during the blood pressure measurement , the pressure waveforms in the cuff are registered while performing a step - by - step deflation . the separation and timing of the forward and reflected pulse waves are determined by a special mathematical algorithm . the distance for the pwv equation used by the vasotens was measured according to the bplab user s guide requirements . the quality control method consists of a visual assessment of the curves in the vasotens clinical report screen . the pulse time index of norm ( ptin ) is calculated by the vasotens for the estimation of the 24-hour pwv . the principle of the ptin calculation is where tm is the entire period of monitoring and t1 , t2 , and tn represent the periods in which the pwv does not exceed the cut - off value of 10 m / second . essentially , all the data are shown as the mean and standard deviation ( sd ) . we used bpstat software , version 05.00.04 ( bplab ) to tabulate all the indices of every measured 24-hour waveform automatically . the ptins in different periods before and after renal transplantation are illustrated in figure 1 . as shown in figure 1 , before kidney transplantation as our analysis showed , this value did not depend on the duration of the history of the disease or the time of the interdialysis period at which the monitoring was performed . then , a week after the renal transplantation , we observed a decrease in the ptin in most cases . the mean ptin in the whole group at this period was 27.6 ( sd , 11.1 ) . after 20 weeks , the mean ptin in the whole group increased again to 52.0 ( sd , 23.6 ) , but the detailed analysis showed that those patients who had a higher value of ptin before transplantation had a higher increase at this time . using the receiver operating characteristic curve , we determined the cutoff value of ptin that could predict the two ptin states : a state of improvement or a state of decline / without change ( figure 2 ) . the cutoff value of ptin at 45% had a sensitivity of 69% , specificity of 76% , and area under the curve of 0.65 to predict these states . for the detailed baseline characteristics of the patient groups separated according to this cut - off point , please see table 1 . as shown in table 1 , there was no significant difference between the groups for almost all characteristics except the ptin . the difference in preoperative dialysis period ( p = 0.0405 ) and the tendency toward a difference in age ( p = 0.0590 ) should be noted . the ptin at different periods before and after renal transplantation in the groups with ptin of 45% or higher or less 45% is illustrated in figure 3 . the analysis of variance showed that in the first group , the ptin changed significantly ( p < 0.05 ) , whereas in the second group , the ptin was not significantly different . the effect of renal transplantation on blood pressure ( table 2 ) was similar to the effect on the ptin . some authors have noted an improvement in the as after kidney transplantation.68 a number of studies have shown that after kidney transplantation , the disturbances in calcium and phosphate metabolism improve in general , but the media calcification , structural alterations of the arterial wall , and disturbed mechanical vessel wall properties persist.9,1315 in our study , we found that the persistence of these disturbances after kidney transplantation appears to be relatively predictable : there are clear differences in the clinical conditions of patients who develop an excess in the pwv over the cutoff value for either a small or large percentage of the monitoring period . if ptin is 45% or higher before kidney transplantation , there appears to be a good chance that the ptin will improve in the remote period after transplantation . this improvement is particularly important for the management in the initial period after implantation , when increased damage to the arterial wall , resulting in a decreased ptin in most patients , is observed . it is known that the prevalence of postoperative hypertension in patients with renal transplantation is high , and this is one reason for an aggressive therapeutic approach by physicians , reflected by administering more antihypertensive medications.16 the ptin seems to give us an opportunity to optimize this approach . regarding the influence of hemodialysis on the variability of the pwv , a study in which the measurements were performed immediately before ( pre ) and 1 hour after ( post ) the end of each dialysis session should be noted . cyclic intradialysis changes in the pwv were similar during the three dialysis sessions ; as a consequence , all postdialytic pwv values were lower with respect to the predialytic levels.17 as our analysis showed , the ptin did not depend on the time of the interdialysis period at which the monitoring was performed . in our opinion , this mismatching is a result of the smoothing effect of the nocturnal pattern of pwv in ptin , which integrates the pwv values over the course of 24 hours . thus , the analysis of the 24-hour pulse wave velocity in the management of patients with renal transplantation using ptin is feasible .
the aim of our study was to assess the feasibility of using an approach to 24-hour pulse wave velocity ( pwv ) analysis similar to ambulatory blood pressure monitoring analysis in the management of patients with renal transplantation . 
 overall , 41 patients aged between 18 and 55 years who had end - stage renal disease resulting from glomerulopathy were recruited from the kidney transplant waiting list . 
 all the measurements were performed before kidney transplantation and at 1 and 20 weeks after transplantation . 
 the pulse time index of norm ( ptin ) was calculated with the vasotens technology for the estimation of the 24-hour pwv , defined as the percentage of the 24-hour period during which the pwv does not exceed 10 m / second . before kidney transplantation , 
 the mean ptin in the whole group was 56.3 ( standard deviation , 18.4 ) . 
 then , a week after the renal transplantation , a decrease in the ptin was observed in most cases , going to 27.6 ( standard deviation , 11.1 ) . after 20 weeks 
 , the mean ptin in the whole group increased again to 52.0 ( standard deviation , 23.6 ) . in our study , we found that the persistence of arterial stiffness disturbances after kidney transplantation appears to be relatively predictable . 
 we determined the cutoff value of ptin that could predict the two states of ptin : a state of improvement or a state of decline / without change . 
 the cutoff value of ptin at 45% had a sensitivity of 69% , specificity of 76% , and area under the curve of 0.65 . 
 the analysis of variance showed that in the group with an initial ptin of 45% or higher , the ptin in the remote period after transplantation changed significantly ( p < 0.05 ) , whereas in the group with an initial ptin lower than 45% , there were no significant changes . 
 thus , the analysis of 24-hour pulse wave velocity in the management of patients with renal transplantation using ptin is feasible .