Early experience with a new ePTFE vascular prosthesis for hemodialysis

Insertion of Short Introducer Sheaths into a Polyurethane Vascular Access Graft for Immediate Hemodialysis Access

While native AV fistulae are considered the “gold standard” for hemodialysis patients in need of long-term access, synthetic grafts are the best option for patients who are not candidates for an AV fistula. While AV fistulae should be allowed to mature for 3 – 4 months prior to cannulation, PTFE grafts may be cannulated 14 days after placement. Despite the benefit of earlier cannulation in PTFE graft recipients compared to AV fistulae patients, one critical limitation is that immediate post-operative cannulation is not possible. The self-sealing nature of the polyurethane Vectra® Graft overcomes the time restriction until first cannulation, allowing much earlier vascular access than conventional PTFE grafts. We describe here a procedure for insertion of 5-French DialEase™ Introducer Sheaths into the Vectra Graft for immediate, post-operative hemodialysis access. This procedure eliminates time restrictions until first cannulation of the Vectra Graft; the sheath's large diameter side-port ensures high flow for efficient hemodialysis. Moreover, insertion of the sheath into a new or existing Vectra Graft provides vascular access for inspection of the graft anastomoses, angiography, angioplasty, venography, and declotting procedures. The post-operative introduction of DialEase Sheaths into a Vectra Graft for immediate hemodialysis was successfully performed in 35 patients. All patients then immediately received high-flow hemodialysis (400 – 500 ml) with venous pressures ≤ 125 mmHg and negative arterial pressure ∼100 mmHg. To date, there have been no infections, immediate graft thrombosis or other complications associated with this procedure, and all patients have remained free of anastomotic problems.

Early cannulation graft Flixene™ for conventional and complex hemodialysis access creation

PURPOSE

The Flixene™ (Atrium™, Hudson, NH) is a trilaminate composite polytetrafluoroethylene (PTFE) graft that allows access within 72 hours. We evaluate our initial experience with this device for conventional and complex hemodialysis access creation.

METHODS

Retrospective review in end-stage renal disease (ESRD) patients who underwent access creation with Flixene from January 2013 to July 2014. For our analysis, the patients were divided in two groups: those with complex access configurations tunneled in the chest and/or abdominal wall (thoraco-abdominal wall access [TAWA]), and those tunneled in conventional sites (extremity access [EA]). Patient's demographics, indications, complications, reinterventions, patency rates and factors influencing outcomes were evaluated.

RESULTS

In 19 patients (54% men; mean age 44 years ± 18), 24 grafts were implanted, (13 EA [54%] vs. 11 TAWA), all patent after surgery. Central venous occlusive disease (CVOD) was present in all patients with TAWA and in 7/13 (54%) EA patients (p = 0.016). Early cannulation (within 72 hours) was successful in 12 EA and 5 TAWA grafts (p = 0.044). Complication rates including infection, thrombosis, bleeding and steal syndrome were 8/11 (73%) in TAWA and 5/13 (38%) in EA (p = 0.02). At 12 months, primary patency rates for EA and TAWA were 25% and 41%; secondary patency rates were 55% and 41%, respectively.

CONCLUSIONS

Early cannulation (EC) grafts are viable alternatives for conventional and complex access creation that allowed early cannulation (<72 hours) in 17 (70%) of our cases. Primary and secondary patency rates at 12 months were equivalent to data reported on ePTFE grafts.

Polyurethane Grafts: A Viable Alternative for Dialysis Arteriovenous Access?

Polyurethane grafts, promoted for their self-sealing properties and low complication rates, were recently introduced for hemodialysis access. We review our experience with this graft material to determine its complication and patency rates. Between January 1995 and December 1999, 118 patients, 75 female and 43 male, with a mean age of 51 years, had a total of 163 polyurethane arteriovenous grafts inserted. The grafts were mostly 6 mm in diameter (69.3%), placed in a loop configuration (91.4%) in the forearm (49.7%). The median follow-up period was 12 months. The grafts were first cannulated for hemodialysis at a median time of 19 days after implantation, with 12% used within 3 days. Thrombosis and infection were the most common complications at rates of 32.7% and 30.0%, respectively. Infection was the most common cause of graft loss (61.5%). These complications were amenable to salvage intervention. The 1-year primary and secondary patency rates were 73% and 86%, respectively; the 3-year secondary patency rate, 72%. The 1-year serviceability rate was 64%. With satisfactory patency rates and the advantage of its self-sealing properties permitting early cannulation, polyurethane grafts provide a viable alternative for hemodialysis access. Early recognition and appropriate management of complications can prolong graft survival.

Early Cannulation Prosthetic Graft (Flixene™) for Arteriovenous Access

Purpose

Preferred hemodialysis (HD) access is an autologous fistula. Vascular grafts are used in patients with vessels unsuitable to accomplish an arteriovenous fistula (AVF). It is recommended that most current grafts mature in situ for 2–3 weeks before being accessed. Graft complications occur because the structure was not designed for the trauma of repeated cannulation. This study graft has a different structure that enables early use. Its design minimizes weeping through the graft walls and is meant to endure repeated access, thus minimizing the use of HD catheters. The purpose of this study was to show that the Flixene™ graft can be safely placed in patients where fistulas have failed and can be cannulated in 24–72 hr, while maintaining patency rates similar to other polytetrafluoroethylene (PTFE) grafts on the market. Flixene™ configuration should also reduce the incidence of pseudoaneurysms and seromas.

Methods

A prospective two-center study placed 33 grafts in 33 patients; graft efficacy, post-operative complications, and patency were evaluated. Ease of cannulation and dialysis center complications related to early cannulation were documented. Six month follow-up data was analyzed.

Results

Successful access was achieved in all 33 patients within 72 hr (29 patients within 24 hr). Overall primary patency at 6 months was 49%; primary-assisted patency at 6 months was 80%. No pseudoaneurysms or seromas were documented at 6 months. Complications were typical of graft access.

Conclusion

Early cannulation was successful in all patients. Primary and secondary patency rates at 6–months were equivalent to other data reported on PTFE grafts. Flixene™ successfully prevented pseudoaneurysm and seroma formation at 6 months of prospective follow-up. This graft is a better last-resort option for patients who cannot receive a fistula, compared to double-lumen cuffed catheters.

AXILLOFEMORAL FISTULA FOR HEMODIALYSIS ACCESS

The authors describe the technique of axillo-femoral arteriovenous prosthesis interposition and evaluate their experience with this non-conventional access for hemodialysis.

Long-term Follow-up of Polyurethane Vascular Grafts for Hemoaccess Bridge Fistulas

The new polyurethane vascular graft (PVG) has been reported to be better than the expanded polytetrafluoroethylene (PTFE) graft in terms of early access and prompt hemostasis, but long-term patency and safety of PVGs have not been investigated objectively. To evaluate late clinical outcome of the PVG, we compared the complication and patency rates of stretch PTFE grafts with those of PVGs implanted for hemodialysis vascular access. Subjects were 53 patients who received 58 arteriovenous grafts between October 1997 and July 2000. They were divided in a prospective fashion into two groups according to the type of implanted graft: PVG ( n = 30) or PTFE ( n = 28). The study group comprised 27 men and 31 women with a mean age of 61.7 +/- 10.9 years (range: 23-84 years). The average number of previous accesses was 5.1 +/- 3.1 (range: 0-12). There were no differences between the groups in term of age, sex, body surface area, etiology of renal disease, presence of diabetes, previous access procedures, anatomical positions of grafts, or mean follow-up period. Primary patency rates for the PVG and PTFE grafts were equivalent at 1 year (60.7% vs. 56.5%) and at 2 years (54.7% vs. 51.8%). Similarly, secondary patency rates for the two groups did not differ at 1 year (78.7% vs. 79.9%) or at 2 years (78.7% vs. 69.3%). These findings indicate that the PVG is an acceptable alternative to the PTFE graft for blood access.

A novel technique designed to minimize the morbidity of failure of arteriovenous access in hemodialysis patients

The failure of dialysis access grafts leads to significant morbidity rates in patients with end-stage renal disease. We describe a novel technique for the insertion of new polytetrafluoroethylene graft segments designed to reduce this morbidity rate. Patients found to have significant intragraft deterioration at thrombectomy undergo insertion of a new nonanastamosed graft parallel to the existing graft. At the next failure of the existing graft, the nonanastamosed segment is anastamosed and used immediately for dialysis, obviating the need for a temporary catheter. Thirty patients have undergone this technique, and 89% of those who returned to surgery have had successful anastamosis of their new segments. Two patients were found to have inadequate incorporation of their new segments into the subcutaneous tissue, and one became frankly infected.

Comparative study of use of Diastat versus standard wall PTFE grafts in upper arm hemodialysis access

The objective of this study was to review our experience with using brachioaxillary Diastat vascular grafts (Diastat) compared to standard wall brachioaxillary PTFE grafts (sPTFE) in two similar groups of hemodialysis patients. We conducted a retrospective study comparing complications and graft survival in two similar groups (in terms of age, diabetes mellitus, surgical technique, and previous vascular access) of hemodialysis patients during the period 1994-1997 who had received Diastat (n = 40) or (sPTFE) (n = 40) grafts. We found that the Diastat graft for upper arm hemodialysis access has lower patency and higher complication rates than sPTFE grafts.

Can Diastat Grafts Meet the Challenges of Daily Punctures?

To determine whether Diastat grafts can meet the challenges of daily needle punctures required for home hemodialysis (HD), a retrospective analysis was performed on the experience with 47 grafts placed in 44 patients receiving HD three times a week. The control group consisted of 17 patients who received 17 stretch polytetrafluoroethylene (s-PTFE) grafts. Apart from their ability to better contain bleeding after needle withdrawal, in all measures of longevity the Diastat grafts were outperformed by the s-PTFE grafts. No more direct data exist to address the original challenge.

Australian multicentre evaluation of a new polyurethane vascular access graft

BACKGROUND

A new three-layered cast polyurethane vascular access graft (Thoratec VAG) is the most recent addition to the list of materials used in the search for the perfect prosthetic graft material for haemodialysis vascular access. Despite its use in 23 countries, a clinical assessment has not been published.

METHODS

An independent retrospective evaluation by questionnaire was obtained for 145 implantation procedures performed by 30 surgeons.

RESULTS

Ninety-two per cent of procedures were performed for an acute need for vascular access and 73% had prior failed vascular access surgery. Patients were hospitalized for a median of 4 days and the graft was initially used at a median of 3 days. Median follow-up was 306 days. Thoratec VAG had a problem-free (primary) patency of 44.9% and a functional (secondary) patency 64.5% at 1 year. Major causes of graft loss were thrombosis (17%) and infection (11%). Intra-operative thrombosis was the only significant risk factor for subsequent thrombosis (P = 0.013). Infection was less in patients with antibiotic prophylaxis that included vancomycin (P = 0.02).

CONCLUSION

The ability to use the graft soon after surgery is a major advance for patients who urgently need reliable medium to long-term haemodialysis access.

Lessons learned from the DIASTAT vascular access graft

BACKGROUND

The vascular community continues to search for the ideal vascular access graft that will allow early cannulation and avoid temporary central venous catheters.

METHODS

This is a review of the Cranley Surgical Associates' experience with the use of the Gore-Tex DIASTAT (W.L. Gore & Associates, Inc., Flagstaff, Arizona) vascular access graft in 20 patients compared with 20 control patients matched for age, sex and risk factors.

RESULTS

Although the DIASTAT graft is touted for early accessibility and decreased need for central venous access, that was not found to be the case as 14 patients in the DIASTAT group received temporary access catheters. There was significantly more edema in the DIASTAT patients (P = 0.0048). Comparing the time to the first thrombosis or to revision revealed an average of 18 weeks for the DIASTAT group and 56 weeks for the control group. The length of time to thrombosis or revision was significantly longer in the control group (P = 0.0058). Comparison of the number of weeks of function and serviceability of the grafts revealed the average DIASTAT graft functioned for 34 weeks and that of the control group for an average of 70 weeks (P = 0.0131). Comparison of the two groups showed a significant increase in early thrombotic events (< 90 days) in the DIASTAT grafts (P = 0.0013).

CONCLUSIONS

The DIASTAT vascular access graft does not appear to be the ideal hemodialysis access graft.