Registry data highlight long-term trends in hemodialysis access profile of failed kidney transplant patients

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New findings, recently published in the Journal of Vascular Access (JVA), provide insight into the hemodialysis access profile of failed kidney transplant patients treated in the Catalonia region of Spain over an 18-year period. 

Researchers Ramon Roca-Tey, MD, a senior consultant in nephrology from Hospital Universitari Mollet in Barcelona, Spain, and colleagues note that data on vascular access use in failed kidney transplant patients returning to hemodialysis are limited. In the present study, therefore, the investigators sought to analyze the vascular access profile of this patient group, the factors associated with the likelihood of hemodialysis reinitiation through an arteriovenous fistula (AVF), and the effect of vascular access in use at the time of kidney transplant on kidney graft outcomes. 

In their report, Roca-Tey et al write that they examined data from the Catalan Renal Registry on failed kidney transplant patients restarting hemodialysis and incidence hemodialysis patients with native kidney failure over the period from 1998–2016. 

The authors report in JVA that the vascular access profile of 675 failed kidney transplant patients at hemodialysis reinitiation compared with that before kidney transplant, and with 16,731 incident patients starting hemodialysis was 79.3% vs. 88.6% and 46.2% (p=0.001 and p<0.001) for AVF; 4.4% vs. 2.6% and 1.1% (p=0.08 and p<0.001) for arteriovenous graft (AVG); 12.4% vs. 5.5% and 18% (p=0.001 and p<0.001) for tunneled central catheter; and 3.9% vs. 3.3% and 34.7% (p=0.56 and p<0.001) for non-tunneled catheter. In addition, they reveal that the likelihood of hemodialysis reinitiation by AVF was significantly lower in patients with cardiovascular disease, a kidney transplant duration of more than five years, those dialyzed through AVG or tunneled central catheter before kidney transplant, and those of the female sex. 

The authors add that analysis of Kaplan-Meier curves showed a greater kidney graft survival in patients dialyzed through arteriovenous access than in patients using catheters just before kidney transplantation. Finally, Cox regression analysis showed that patients on hemodialysis through arteriovenous access at the time of kidney transplantation had lower probability of kidney graft loss compared to those with catheters, Roca-Tey and colleagues write. 

The authors conclude that the vascular access profile of failed kidney transplant patients returning to hemodialysis and incident patients starting hemodialysis was different. They also note that, compared to before a kidney transplant, the proportion of failed kidney transplant patients restarting hemodialysis with an AVF decreased significantly at the expense of a tunneled central catheter, and that patients on hemodialysis through arteriovenous access at the time of a kidney transplant showed greater kidney graft survival compared with those using a catheter. 

According to the researchers, there are two clinical implications that can be derived from their findings. “To reduce the proportion of failed kidney transplant patients returning to hemodialysis with a central line, better vascular access management is needed,” they state, outlining the first implication. The second implication, Roca-Tey et al believe, arises from the impact of arteriovenous access on kidney graft outcomes. They elaborate: “If our results are confirmed in further studies, including a larger number of kidney transplant patients and not simply patients returning to hemodialysis, routine arteriovenous access closure after a successful kidney transplantation should not be performed.” 

In the discussion of their data, the authors state that a number of factors limit the strength of their findings. They highlight the use of a population registry database for this study as a key weakness, for example. “The variables used are restricted in number and can have low clinical specificity,” they note, giving the example that the number of litigated accesses, as well as those with spontaneous thrombosis and not salvaged, were not recorded. Furthermore, the researchers acknowledge a weakness pertaining to the effect of vascular access on kidney graft survival—a secondary aim of the study. They write: “Kidney transplant patients who returned to hemodialysis were considered instead of all kidney transplant patients, and this may be a bias in our study.”

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