When Using DOPPS Slides Modifying DOPPS data, analyses, tables, and graphics in any form is not permitted without prior approval from the DOPPS coordinating center staff. Each DOPPS slide used must include the citation of the associated publication and feature the corresponding DOPPS logo.

DOPPS Slide Use Guidelines Modifying DOPPS data, analyses, tables, and graphics in any form is not permitted without prior approval from the DOPPS coordinating center staff. Each DOPPS slide used must include the citation of the associated publication and feature the corresponding DOPPS logo.

Enhanced Training in Vascular Access Creation Predicts Arteriovenous Fistula Placement and Patency in Hemodialysis Patients: Results from the Dialysis Outcomes and Practice Patterns Study

Introduction

DOPPS Background DOPPS refers to the Dialysis Outcomes and Practice Patterns Study DOPPS is a large international study to identify dialysis unit practices associated with the best outcomes for chronic hemodialysis patients Major outcomes studied are: mortality, hospitalization, vascular access and QoL DOPPS is sponsored by an unrestricted scientific/educational grant from Amgen and Kirin

Methods (1)

Methods (2)

Table 1: Questions about surgical training and practice patterns answered by the primary vascular access surgeon at each facility Table 1 shows the overall percentage of responses by type of vascular access surgeon. Vascular surgeons were the most common surgical subspecialty among vascular access surgeons across the DOPPS countries (nearly 55%). However, notable country differences were evident. In Italy, nephrologists performed most vascular access surgeries in the majority of facilities (85%). In contrast, vascular surgeons were the primary surgeons for accesses in facilities in Germany and Spain (92%) and Canada (81%). In the United States, while 61% of access surgeries were conducted by vascular surgeons, 31% of facilities were served by general surgeons. Table 1 shows the mean number of fistulae and grafts created by vascular access surgeons during their surgical training.

Table 2: Odds of fistula versus graft placement among HD patients as a function of the type/number of vascular accesses (VA) placed during training and the degree of emphasis on VA during training Table 2 shows results from logistic regression models examining odds of fistula versus graft placement at a facility, based on characteristics of vascular access surgeon training and experience variables from the questionnaire. For every doubling of the number of fistulae placed during training, there was a much higher odds of placing an fistula versus a graft in practice (adjust odds ratio [AOR]=2.17, p<0.0001). For every doubling of the number of grafts placed during training, there was a 45% lower odds of a patient receiving fistula versus graft (p<0.0001). For every 10% increase in the percentage of fistulae placed during training, there was a 53% higher odds of fistula versus graft placement (p<0.0001). Furthermore, ‘Much emphasis to extreme emphasis’ (compared with ‘no emphasis’) on vascular access creation during training was associated with 2.74-fold higher odds (p=0.0002) of fistula placement within dialysis facilities served by these surgeons. There was a trend toward lower odds of fistula versus graft placement for the subspecialty of vascular surgery versus other surgical subspecialties (all countries: AOR=0.75, p=0.09; United States alone: AOR=0.79, p=0.42; all non-U.S. countries: AOR=0.71; p=0.10).

Figure 1a. Variation across countries in permanent vascular access use in a prevalent cross-section of hemodialysis patients . Figure 1A and 1B show numbers and proportions of grafts and fistulae by country for prevalent and incident hemodialysis patients, respectively, at study initiation. In all countries except the United States, fistulae comprised 79%-100% of all permanent accesses used by prevalent or incident patients at study entry.

Figure 1b. Variation across countries in permanent vascular access use in incident hemodialysis patients (within seven days of starting dialysis; at study start (2002-2003) In contrast, fistulae comprised 43% and 52% of baseline permanent access use among U.S. prevalent and incident hemodialysis patients respectively.

Figure 2a. Major domains of vascular access surgical training Figure 2a. Major domains of vascular access surgical training. Mean estimated number of accesses placed by vascular access surgeons during training, by country Figure 2A displays, by country, the mean number of vascular accesses (fistulae, grafts, and catheters) placed by vascular access surgeons during surgical training. The lowest number of accesses placed during surgical training was seen in the United States (n=16) and Belgium (n=39), which was significantly lower than all other countries in the DOPPS (p≤0.004). The number of accesses placed during training was highest in Germany (n=426, more than 20 times higher than in the United States), followed by Canada (n=171) and the United Kingdom (n=132). When considering the mean number of accesses placed during surgical training, more than 50% were fistulae in all countries except the United States, where relatively more grafts were placed during training than fistulae (Figure 2A).

Figure 2b. Major domains of vascular access surgical training Figure 2b. Major domains of vascular access surgical training. Wide variability in the degree of emphasis on vascular access creation during training, by country Figure 2B shows wide variation by country. The majority of respondents from Italy (85%) and 57% from Germany indicated a high degree of emphasis on VA during surgical training compared with 20% of U.S. respondents. There was a significant difference in the percentage of surgeons who indicated a high degree of emphasis on vascular access training between the United States and the countries of Belgium, France, Germany, Italy, Japan, and Spain (p<0.05).

Figure 3. Time to primary fistula failure in hemodialysis patients for tertiles of the number of AVF created by the facility’s primary surgeon during surgical training Results from Cox regression models, where the number of fistulae created during surgical training (in tertiles) was assessed as a predictor of primary and secondary fistula failure, are shown in Figure 3. Survival curves highlight results for time to primary fistula failure, based on the number of fistulae created during surgical training. The reference group was creation of <25 fistulae during training. Making ≥25 fistulae during surgical training was associated with a significantly lower relative risk (RR) of fistula failure (RR=0.66, p=0.002 for primary failure; RR=0.60, p=0.004, for secondary failure compared with 0-24 fistulae created during training). However, there was no significant difference between categories of 25-75 or >75 fistulae created during training regarding the relative risk for primary or secondary fistula failure. When the fistula survival analyses were also adjusted for either the number of years the surgeon had been placing vascular accesses or the number of years since surgical training, neither factor was significantly related to fistula survival.

Conclusions

Acknowledgements