Long-term results of autologous scaffold-free tissue-engineered vascular graft for hemodialysis access

BACKGROUND

The growing size of the end stage renal disease (ESRD) population highlights the need for effective dialysis access. Exhausted native vascular access options have led to increased use of catheters and prosthetic shunts, which are both associated with high risks of access failure and infection. Emerging alternatives include tissue-engineered vascular grafts (TEVG). Here we present the endpoint results for 10 ESRD patients with the scaffold-free tissue-engineered vascular access produced from sheets of extracellular matrix produced in vitro by human cells in culture.

METHODS

Grafts were implanted as arteriovenous shunts in 10 ESRD patients with a complex history of access failure. Follow-up included ultrasound control of graft morphology and function, dialysis efficiency, access failure, intervention rate, as well as immunohistochemical analysis of graft structure.

RESULTS

One patient died of unrelated causes and three shunts failed to become useable access grafts during the 3-month maturation phase. The 12-month primary and secondary patency for the other six shunts was 86%. Survival of six shunts functioning as the vascular access was 22 ± 12 months with longest primary patency of 38.6 months. The dialysis event rate of 3.34 per patient-year decreased significantly with the use of this TEVG to 0.67.

CONCLUSIONS

This living autologous tissue-engineered vascular graft seems to be an alternative to synthetic vascular access options, exhibiting advantages of native arteriovenous fistula.

Preventing catheter-related infections in children undergoing hemodialysis

The increased use of tunneled cuffed catheters in children on chronic hemodialysis is the result of their relative ease of insertion, pain-free dialysis and immediate use. The disadvantage of their use is that they are associated with catheter-related bacteremia (CRB), which in turn is related with increased morbidity, access loss and occasionally metastatic infections and even death. A CRB might be difficult to diagnose and is often associated with a previous history of CRB, exit-site infection, low serum albumin and long duration of catheter use. There is evidence that the use of arteriovenous fistulae is associated with lower infection rates. The implementation of effective strategies for the prevention of CRBs include the adoption of policies for improving arteriovenous fistula rates, appropriate surgical catheter insertion and optimal nursing care of the exit site, and a safe connection technique. Recently, the effectiveness of antimicrobial catheter solutions for preventing CRB has been documented in a number of randomized clinical trials. In addition, the application of antibiotic ointments at the exit sites of tunneled cuffed catheters might be significant for the reduction of Staphylococcus-related CRB. The upside is that education-based programs combining specific preventive measures can significantly reduce CRBs.

Effect of antimicrobial locks for tunneled hemodialysis catheters on bloodstream infection and bacterial resistance: a quality improvement report

BACKGROUND

Catheter-restricted antimicrobial lock (AML) use reduces catheter-associated bloodstream infection (CA-BSI) in clinical trial settings, but may not be as effective in clinical settings and may increase bacterial resistance.

DESIGN

Quality improvement report analyzed using a cross-sectional time series (unbalanced panel) design.

SETTING & PARTICIPANTS

The study cohort comprised all prevalent adults treated with hemodialysis through a tunneled catheter for any, but not necessarily all, of the time from January 1, 2003, to June 30, 2006, in Manukau City, New Zealand (135,346 catheter-days, 404 tunneled catheters, 320 patients).

QUALITY IMPROVEMENT PLAN

Catheter-restricted AMLs (heparin plus gentamicin) for all tunneled catheters from July 1, 2004.

MEASURES

Repeated observations of CA-BSI, hospitalization, tunneled catheter removal, and death from CA-BSI analyzed by using generalized estimating equations with a single level of clustering for each tunneled catheter and patterns of bacterial resistance analyzed by using simple descriptive statistics.

RESULTS

AML use was associated with reductions in rates of CA-BSI and hospitalization for CA-BSI by 52% and 69% for patients with tunneled catheters locked continuously with AMLs since their insertion compared with those with tunneled catheters that were not, respectively. AML exposure also was associated with a trend to increased gentamicin resistance amongst coagulase-negative staphylococci isolates, a pattern similar to that observed for BSIs in our general hemodialysis population in which tunneled catheters were not the source of BSI, but different from that in the general non-end-stage renal disease population in the region.

LIMITATIONS

This is an uncontrolled observational study and cannot prove causality. The follow-up period of 18 months is longer than for other studies, but still too short to definitely answer whether AML use drives bacterial resistance.

CONCLUSIONS

A change to use of AMLs may improve clinical outcomes; however, additional study of associated bacterial resistance is needed before AML use becomes standard care.