Effect of Donor- and Recipient-Related Factors on Arterial Resistance Index After Kidney Transplant.

BACKGROUND: The assessment of color Doppler resistance index (RI) of the intra-renal arteries has been shown to be a good predictor of short-term and long-term graft survival after kidney transplant. In this study, we investigated the influence of donor- and recipient-related factors on RI evaluated early after kidney transplant. METHODS: We prospectively analyzed 90 kidney transplant patients who underwent RI assessment within the first month after the transplant, subdivided into 2 groups according their RI values lower (group A) or higher (group B) than 0.646 (median value). RESULTS: Patients in group A had a lower human leukocyte antigen (HLA) mismatch number (3.3 ± 1 versus 3.9 ± 0.9, P = .007) and were significantly younger (42.8 ± 11 years versus 47.8 ± 11 years, P = .03) than patients in group B. All the others variables examined were not significantly different between the 2 groups. Multivariate logistic regression analysis confirmed that HLA mismatch number (P = .03) and recipient age (P = .03) are independent predictors of RI. CONCLUSIONS: Our data suggest that HLA mismatches and donor age can influence recipient kidney vascular resistance in the early period after transplantation.

Multidrug-resistance 1 gene single-nucleotide polymorphisms do not influence long-term graft survival after kidney transplantation.

BACKGROUND: The single-nucleotide polymorphisms (SNPs) of the Multidrug resistance 1 (MDR1) gene have been associated with changes in the pharmacokinetics of cyclosporine (CsA) and tacrolimus (FK506). Our aim was investigate the influence of MDR1 SNPs on long-term graft survival in a population of kidney transplant recipients. METHODS: We retrospectively analyzed 154 patients; they were genotyped for the SNPs C1236T, G2677T/A, and C3435T and evaluated for the influence of those 3 SNPs on CsA or FK506 pharmacokinetics and on long-term graft survival. RESULTS: Thirty-one patients were wild-type for C1236T, G2677T/A, and C3435T polymorphisms (group A), 76 patients had ≥1 heterozygous mutations (group B), and 47 patients had ≥1 homozygous mutations (group C). CsA-receiving patients in group C needed a significantly higher oral dose than patients in groups B and A (P=.02). No differences in FK506 trough level nor in oral dose taken were observed in FK506-receiving patients. Kaplan-Meier analysis did not show survival differences in the 3 groups, and Cox proportional hazards model confirmed that the MDR1 SNPs did not represent a risk for graft loss. CONCLUSIONS: Pretransplantation determination of MDR1 SNPs may be helpful to optimize the starting dose of CsA but can not predict long-term graft survival.

The effects of preemptive therapy using a very low threshold of pp65 antigenemia to prevent cytomegalovirus disease in kidney transplant recipients: a single-center experience.

BACKGROUND: Preemptive therapy is a valid option for cytomegalovirus (CMV) disease prevention in kidney transplant recipients. However, there are controversies regarding the appropriate threshold value to be reached before starting antiviral drugs. The aim of this study was to evaluate the benefit of a low threshold of the CMV pp65 antigenemia test as a guide to initiate the therapy. METHODS: We performed a prospective study on 47 consecutive kidney recipients. The CMV pp65 antigenemia test was performed over 6 months posttransplantation; patients who displayed ≥ 2/200,000 CMV antigen-positive leukocytes were treated for 2 months with valgancyclovir (450 mg twice a day). RESULTS: Twenty-five patients developed CMV infections, which were initially diagnosed at 55 ± 25 days posttransplantation. The number of CMV antigen-positive cells/200,000 leukocytes on the first positive test was 17 ± 22. The test first became negative at 17 ± 8 days after the diagnosis. A positive correlation was observed between the number of CMV antigen-positive cells and the time to obtain the first negative test (P = .01). At the end of follow-up (35.3 ± 16.4 months), none of the patients had developed CMV syndrome. Among the CMV-positive recipients, the creatinine levels showed no differences from the values before the CMV infection. No difference in creatinine levels was noted between CMV infection positive versus negative patients. CONCLUSION: Our data suggested that a CMV antigenemia titer ≥ 2/200.000 leucocytes can be considered to be an appropriate threshold to start anti-CMV preemptive therapy.

Loss of renal function is associated with deterioration of health-related quality of life in kidney transplant patients.

OBJECTIVE: The evaluation of health-related quality of life (HRQOL) is becoming an important measure of the outcomes of kidney transplantation. The aim of this study was to evaluate whether deterioration of renal function was associated with a worse HRQOL in kidney transplant patients (KTP) compared with patients experiencing chronic native kidney insufficiency. PATIENTS AND METHODS: HRQOL was assessed in 128 stable KTP and 102 chronic kidney disease patients (CKDP) using the SF-36 health survey. The 2 groups were matched for age, sex, sociodemographic conditions, and renal function, the only difference being that KTP had experienced hemodialysis treatments before transplantation. RESULTS: Overall, KTP revealed a satisfactory HRQOL compared with CKDP. At variance with CKDP, KTP with estimated creatinine clearances >60 mL/min versus <60 mL/min showed higher scores among 7 of 8 SF-36 categories: physical function (PF), role physical (RP), bodily pain (BP), general health (GH), vitality (VT), role emotional (RE), and mental health (MH). Estimated creatinine clearance showed a significant positive correlation with PF (P = .0004), RP (P = .008), BP (P = .01), GH (P = .0001), VT (P = .001), RE (P = .03), and MH (P = .02), but exclusively in KTP. Multiple regression analysis confirmed in KTP that the scale scores of PF, RP, GH, VT, and RE were significantly dependent on creatinine clearance. CONCLUSION: Our data demonstrated that among KTP deterioration of renal function was associated with a worse HRQOL.

[Vitamin B12 clearance (Kd-B12) in hemodialysis (HD) and hemodiafiltration (HDF)]. / La clearance della vitamina B12 (Kd-B12) in emodialisi (HD) e in emodiafiltrazione (HDF).

PURPOSE: The dialysis dose is usually assessed by Kt/V urea; however, it is possible that middle molecule (MM) removal could play a role in optimal treatment. Vitamin B12 is a classical MM marker and Kd-B12 is used to compute a MM-based dialysis index, requiring a weekly total clearance (Kd-B12 + renal creatinine clearance (CrCl) > or =30 L, corresponding to IDB12> or =1 (Babb et al, Kidney Int, 1975). Recently, it was demonstrated that by increasing the total Kd-B12 per session (TCV) from 10 to 16 and to 26 L, the relative risk (RR) of death was reduced from 1 to 0.79 and to 0.62, respectively (Leypoldt et al, Am J Kidney Dis 1999). This implies that a minimum TCV of 16 L, but preferably of 26 L per session, should be delivered, for anuric HD patients on a 3x/wk schedule. To extend these results to the whole hemodialysis (HD) population, we suggest transforming TCV into the corresponding IDB12 values: i.e. a TCV=10 L on 3x/wk corresponds to IDB12=1, a TCV=16 and 26 L corresponds to IDB12=1.6 and 2.6, respectively. METHODS: This study aimed to assess Kd-B12 and IDB12 for all stable patients in our unit. There were 62 patients (33 males, 29 females): five patients were being dialyzed once per week (1x), nine patients twice (2x), 46 patients three (3x) and two patients four times (4x) per week (wk); the session length was 232+/-18 min. Most dialyzers had a large surface area (mean 1.9+/-0.3 m2), with KoA-B12=211+/-92 mL/min. Eleven patients, 3x/wk, were on hemodiafiltration (HDF): the reinfusion rate was 33+/-3 mL/min in five patients (sHDF) and 76+/-12 mL/min in six patients (HDF on-line (OL). Kd-B12 was computed as a function of KoA-B12, effective plasma flow, Qd and ultrafiltrate (UF). IDB12 was computed from Kd-B12, ses-sion length and schedule, CrCl and body surface area. RESULTS: The main results are given below: [table: see text] On average, Kd-B12 was 105 +/- 13 mL/min on HD and 152+/-34 mL/min on HDF. A significant difference was found only for HDF-OL and was essentially due to the higher UF. Of note, the presence of renal function allowed good IDB12 values for 1x/wk and 2x/wk patients, even better than for the standard 3x/wk patients. CONCLUSIONS: We have demonstrated that most available dialyzers provide high Kd-B12 values (but HDF-OL performs significantly better) and that IDB12, by quantifying the impact of UF, session length, schedule and renal function, allows the assessment of dialysis adequacy beyond Kt/V urea, for all HD or HDF patients, on a routine basis and at no added cost.

Successful use of central venous catheter as permanent hemodialysis access: 84-month follow-Up in lucania.

Cuffed tunneled venous access catheters are commonly used for temporary and permanent access in hemodialysis (HD) patients. These catheters serve an essential role in providing permanent access in subjects in whom all other access options have been exhausted. The predominant complications are catheter thrombosis, catheter fibrin sheating and infection. The aim of this study was to evaluate long-term survival and complications of permanent venous catheters (PVC) placed for the purpose of HD during the period from January 1992 to December 1998, at the Dialysis Units of Lucania (a southern Italian region). A total of 98 PVC were placed in 88 patients during this period. The catheters used were of three types: (a) 72 VasCath Soft Cell catheters (Bard Instrument Company, Toronto, Ont., Canada); (b) 22 PermCath catheters (Quinton Instrument Company, Seattle, Wash., USA), and (c) 4 Tesio catheters (Bellco SpA, Mirandola, Italy). Survival curves of catheters were calculated using the Kaplan-Meier product-limit estimator. The patient survival was 60% at the 78th month. Actually, 52 patients (27 males, 25 females) are still alive: 15 (26.9%) of these patients have diabetes mellitus and 1 has been transplanted. The actuarial survival rate of PVC was 89% in the whole population studied and 82% in subjects alive after 84 months. Twenty-five patients (28.4%) had PVC as the first reliable vascular access. Long-term complications occurred 27 times (1 episode every 44.81 month/patient) as: breakage (3.1%); thrombosis (10.2%); displacement (2.0%); subcutaneous tunnel bleeding (3.1%); inadequate blood flow (7.1%), and infection (10.2%). In conclusion, our data confirm that PVC might represent an effective long-term blood access route for HD. Again, PVC are getting the access of choice for selected patients (i.e., older subjects with cardiovascular diseases and cancer patients) and are enjoying a dramatic increase in use for subjects who are terrified of repetitive venopuncture.

Jugular vein catheterization for hemodialysis: correct positioning control using real-time ultrasound guidance.

The jugular vein catheterism (JVC) is adopted for blood access in patients with acute renal failure, in chronic renal failure and when patients show failure of traditional vascular access. The technique of catheter insertion in the jugular vein is quick and easy. Usually correct catheter positioning, before starting the dialytic procedure, is controlled by chest X-ray or by intra-cavitary electrocardiogram. The aim of this work is to evaluate the feasibility of the real-time ultrasound guidance to control the correct positioning of the catheter instead of the usual chest X-ray control. We have studied 158 patients with JVC insertion before the hemodialytic procedure; 54 patients have undergone both ultrasound and a chest X-ray control while 104 were only submitted to ultrasound control. The ultrasound procedure includes an under xifoid scanning, with a convex 3.5 Mhz drill to evaluate the four heart cavities. When the right atrium is identified a second operator rapidly infuses in the venous catheter 15 ml of physiological solution thus creating a blood turbolence easily observed in real time as a light jet inside the atrium. This turbolence appears to be the main evidence for good catheter positioning and we were able to show the light jet in 156 (98%) patients. All light jet positive patients were submitted to the hemodialytic procedure without any complications during and after dialysis. We concluded that the intraoperative ultrasound control technique is an alternative to the chest X-ray evaluation because it offers the possibility for safe intraoperative immediate control thus reducing the total costs of the procedure.

Reconciliation between urea kinetics and direct dialysis quantification.

Previous studies comparing urea kinetic model (UKM) and direct dialysate quantification technique (DDQ) found statistically different results as far as the urea distribution volume (V) and protein catabolic rate (PCR) are concerned. In these studies, however, the true values for both the dialyser urea clearance (K) and urea concentration (C) were not used. The aim of this study was to compare UKM and DDQ using for both methods a variable-volume single-pool (VVSP) model as well as plasma water C and effective K. The study was performed during paired filtration dialysis (PFD) sessions because this technique allows bloodless measuring of K. Twenty dialysis patients were studied during a single PFD session. Dialysate and ultrafiltrate C and urea mass transfer rate were measured every 15 min to compute averaged K and total urea removal. Blood samples were obtained as for a three-point UKM, and an iterative technique was used for both methods. The results (means +/- SD) obtained with UKM were as follows: K = 176 +/- 23 ml/min; V = 29986 +/- 7620 ml, PCR = 65 +/- 15 g/day, Kt/V = 1.04 +/- 0.17. These results were not statistically different from those obtained using DDQ. In conclusion, when methodological errors are avoided, DDQ and UKM provide very similar results. This study shows also that PFD is very useful for studying solute kinetics during dialysis.