Preliminary prospective randomized experience with vascular clips in the creation of arteriovenous fistulae for hemodialysis

Quality assurance in surgical trials of arteriovenous grafts for haemodialysis: A systematic review, a narrative exploration and expert recommendations

BACKGROUND

Introducing new procedures and challenging established paradigms requires well-designed randomised controlled trials (RCT). However, RCT in surgery present unique challenges with much of treatment tailored to the individual patient circumstances, refined by experience and limited by organisational factors. There has been considerable debate over the outcomes of arteriovenous grafts (AVG) compared to AVF, but any differences may reflect differing practice and potential variability. It is essential, therefore, when considering an RCT of a novel surgical procedure or device that quality assurance (QA) is defined for both the new approach and the comparator. The aim of this systematic review was to evaluate the QA standards performed in RCT of AVG using a multi-national, multi-disciplinary approach and propose an approach for future RCT.

METHOD

The methods of this have been previously registered (PROSPERO: CRD420234284280) and published. In summary, a four-stage review was performed: identification of RCT of AVG, initial review, multidisciplinary appraisal of QA methods and reconciliation. QA measures were sought in four areas - generic, credentialing, standardisation and monitoring, with data abstracted by a multi-national, multi-speciality review body.

RESULTS

QA in RCT involving AVG in all four domains is highly variable, often sub-optimally described and has not improved over the past three decades. Few RCT established or defined a pre-RCT level of experience, none documented a pre-trial education programme, or had minimal standards of peri-operative management, no study had a defined pre-trial monitoring programme, and none assessed technical performance.

CONCLUSION

QA in RCT is a relatively new area that is expanding to ensure evidence is reliable and reproducible. This review demonstrates that QA has not previously been detailed, but can be measured in surgical RCT of vascular access, and that a four-domain approach can easily be implemented into future RCT.

A critical review of surgical strategies to minimise venous stenosis in arteriovenous grafts

It is inevitable that complications arising from surgical procedures are ascribed to surgical technique, and this applies to venous stenosis (VS) in arteriovenous grafts. However, despite a wide range of cellular studies, computer modelling, observational series and clinical trials, there remains uncertainty on whether surgical technique contributes to VS. This article reviews evidence from basic science, fluid dynamics and clinical data to try and rationalise the main surgical options to modify the occurrence of venous stenosis. There is sufficient data from diverse sources to make recommendations on clinical practice (size of target vein, shape of anastomosis, angle of approach, distance from venous needling, trauma to the target vein) whilst at the same time this emphasises the need to carefully report the practical aspects of surgical technique in future clinical trials.

Creation of Native Arteriovenous Fistulas with Interrupted Anastomoses Using a Self-Closing Clip Device - One Clinic's Experience

The nitinol U-CLIP™ Anastomotic Device (Coalescent Surgical, Inc., Sunnyvale, CA) is a self-closing penetrating vascular clip that reduces suture management and eliminates knot tying, thus enabling rapid and precise interrupted suture placement and facilitating creation of an optimal vascular anastomosis. This report describes the use of U-CLIP devices in the surgical creation of native arteriovenous fistulas in 68 chronic hemodialysis patients. Overall, 61 of the 65 fistulas created matured successfully within 8–9 weeks. Radial cephalic fistulas: 93% were mature at 8 weeks. Brachiocephalic fistulas: 69% were mature at 8 weeks. One-stage basilic vein transposition: 100% were mature at 9 weeks. Two-stage basilic vein transposition: 100% were mature at 8 weeks after second stage. The results in this report show the excellent performance of U-CLIP vascular clips in the creation of several types of native arteriovenous fistulas in chronic hemodialysis patients. The fistulas created using the U-CLIP devices had a high maturation rate within a relatively short time period, and provided uniformly high flow rates. The patients in this study were a challenging population, with a high incidence of diabetes mellitus (81% of the patients) and vein sizes that were smaller than typically used for fistula creation. The U-CLIP™ Anastomotic Device offers the opportunity to create superior interrupted anastomoses for AV fistulas, even in patients who would otherwise be considered poor candidates for fistula creation.

Economic Impact of the Beneficial Effect of Changing Vascular Anastomotic Technique in Hemodialysis Access

There is an urgent and compelling need to reduce the morbidity and expense of maintaining hemodialysis vascular access patency. We previously reported the beneficial effects of altering anastomotic technique on vascular access patency from a multicenter clinical trial. Interrupted anastomoses created with nonpenetrating clips showed significant improvement in primary, assisted primary, and secondary patencies of native vein fistulae (AVF) and synthetic arteriovenous grafts (AVG). In the current report, we provide an analysis of the economic impact of these procedures. The economic analysis is based on a subgroup of patients who underwent access procedures as outpatients during years 1998–1999 at a university-affiliated hospital that contributed 23% of procedures described in the multicenter clinical trial. Hospital charges and payments received were determined for fistula placement and for commonly performed surgical and endovascular procedures (thrombectomy and angioplasty) that maintain patency. Financial comparisons were based on the hospital's average accumulative charges and actual payments calculated on a daily basis. Cost curves were generated by using charge and payment data. Financial information was extrapolated to the entire study population to estimate the cost savings for the larger group. Both charge and payment calculations indicated financial benefit with the use of clips. When financial estimates were extrapolated to reflect the national volume, clip usage projected significant savings of $20 million for AVF and $30.8 million for AVG for every 1,000 days of access patency. Replacing conventional sutures with clips can reduce the morbidity and cost associated with maintaining permanent hemodialysis vascular accesses. This beneficial effect may be due to the biologic advantages of interrupted, nonpenetrating vascular anastomoses.

Anastomotic Strategies to Improve Hemodialysis Access Patency—A Review

The number of patients with end-stage renal disease (ESRD) who require maintenance hemodialysis has risen sharply in the past 2 decades. It is estimated that more than 60% of all patients with ESRD who require chronic hemodialysis are accessed through an arteriovenous fistula (AVF) or graft (AVG), and the incidence is increasing at a rate of 2% to 4% per year. The long-term patency rate of an upper extremity AVF or AVG for hemodialysis access remains suboptimal owing in part to progressive stenosis at the venous anastomosis. This article reviews the causative factors of dialysis access-related anastomotic stenosis, or intimal hyperplasia. This article also reviews the clinical experience of various anastomotic strategies to ameliorate the hemodynamic environment in an effort to improve the clinical outcome of hemodialysis access. These strategies include the use of (1) vein cuff at the expanded polytetrafluoroethylene (ePTFE)-venous anastomosis of AVG, (2) cuffed ePTFE dialysis AVG, and (3) anastomotic devices that create an interrupted anastomosis with staples or clips.

Heterotopic renal transplantation in piglets using vascular closure stapler metallic clips or conventional suturing techniques: comparison of vessel growth and macroscopical study

BACKGROUND/PURPOSE

Our aim was to perform a macroscopic and imaging (ultrasonographic and angiographic) evaluation of vascular closure stapler (VCS) metallic clips for renal transplantation in growing piglets to assess their role for transplantation surgery in young children. If these techniques are to be useful, it is necessary to prove that their use avoids one of the main pitfalls of conventional sutures in this setting, namely lack of growth in the suture line.

METHODS

Twenty-four piglets were used for this study. Animals were subjected to a heterotopic renal autotransplantation when they were 45 days old. The right kidney was moved from its normal location to the cranial area of the iliac fossa. The end-to-side anastomoses between the renal artery and vein and the aorta and vena cava, respectively, were performed using VCS metallic clips in 6 animals. Continuous polypropylene suturing was used in another 6 piglets, and continuous polyglycolic acid suture was used in 6 additional piglets. A control group of 6 animals without renal autotransplantation was also included in the study. All animals were allowed to grow for 6 months, during which time serial angiographic and ultrasonographic studies were carried out to assess the existence of vascular flow disturbances or stenosis. Similarly, angiographic measurements were obtained to document growth at the anastomotic site. Longitudinal growth was evaluated postmortem after the 6-month growing period.

RESULTS

Angiography showed significant (P < .001) transverse growth in both arteries and veins belonging to the VCS clips, running absorbable suture, or control groups. No significant difference was observed among the 3 groups. Vascular growth in the running nonabsorbable suture (polypropylene) group, however, was significantly less than in the other 3 groups and did not significantly differ from baseline. Baseline luminal diameters at the anastomotic site as measured by angiography in the VCS group were 3.64 ± 0.40 mm in the artery and 5.30 ± 1.43 mm in the vein. After growth, these values increased to 6.87 ± 0.90 mm and 11.27 ± 2.53 mm, respectively. Significant longitudinal growth was evidenced macroscopically after 6 months in both aorta and vena cava in all groups. On the other hand, significant longitudinal growth in the renal artery and vein were only observed in the control, VCS, and absorbable suture groups.

CONCLUSIONS

In this experimental setting, satisfactory macroscopic and angiographic vascular growth results were obtained using the VCS clips, suggesting that this suture could be the technique of choice in pediatric transplantation surgery.

Hydrostatic comparison of nonpenetrating titanium clips versus conventional suture for repair of spinal durotomies

STUDY DESIGN

Biomechanics.

OBJECTIVE

To compare the hydrostatic strength of suture and nonpenetrating titanium clip repairs of standard spinal durotomies.

SUMMARY OF BACKGROUND DATA

Dural tears are a frequent complication of spine surgery and can be associated with significant morbidity. Primary repair of durotomies with suture typically is attempted, but a true watertight closure can be difficult to obtain because of leakage through suture tracts. Nonpenetrating titanium clips have been developed for vascular anastomoses and provide a close apposition of the tissues without the creation of a suture tract.

METHODS

Twenty-four calf spines were prepared with laminectomies and the spinal cord was evacuated leaving an intact dura. After Foley catheters were inserted from each end and inflated adjacent to a planned dural defect, the basal flow rate was measured and a 1-cm longitudinal durotomy was made with a scalpel. Eight repairs were performed for each material, which included monofilament suture, braided suture, and nonpenetrating titanium clips. The flow rate at 30, 60, and 90 cm of water and the time needed for each closure were measured.

RESULTS

There was no statistically significant difference in the baseline leak rate for all 3 groups. There was no difference in the leakage rate of durotomies repaired with clips and intact specimens at any pressure. Monofilament and braided suture repairs allowed significantly more leakage than both intact and clip-repaired specimens at all pressures. The difference in leak rate increased as the pressure increased. Closing the durotomy with clips took less than half the time of closure with suture.

CONCLUSION

Nonpenetrating titanium clips provide a durotomy closure with immediate hydrostatic strength similar to intact dura whereas suture repair with either suture was significantly less robust. The use of titanium clips was more rapid than that of suture repair.

Dialysis access

Although hemodialysis access procedures are considered the most common vascular procedures performed by either general or vascular surgeons, there is a paucity of level-one evidence in the literature. Randomized controlled trials are limited, and most of these studies have small sample sizes compared with other areas of vascular surgery, that is, carotid or aneurysm studies. We summarize the results of the world's literature for arteriovenous access in table format as a tool for those specialists managing patients with arteriovenous access procedures.

Angiographic, ultrasonographic, and macroscopic assessment of aortic growth after VCS clips, interrupted polypropylene, or running polyglycolic acid anastomosis

BACKGROUND/PURPOSE

Lack of growth after surgery is still an unsolved issue in growing vessels. Aortic surgery is an integral part of vascular pediatric surgery. As an alternative to address this lack of growth in this scenario, we propose the use of titanium clips for vascular anastomosis.

METHODS

Thirty-two domestic swine were used in this study. Animals entered the study when they were 55 days old and were subjected to an end-to-end aortic anastomosis using vascular closure stapler (VCS) clips, interrupted polypropylene, or running polyglycolic acid suture. Control group animals were sham-operated. Pigs were allowed to grow for 6 months, during which time they were subjected to serial ultrasonographic and angiographic studies to assess vascular growth.

RESULTS

VCS clip anastomosis outcome was comparable with polypropylene or polyglycolic acid suture anastomosis. No significant differences in either longitudinal or transversal vascular growth were seen between the 3 studied suturing techniques and the control group.

CONCLUSIONS

Our vascular growth and patency results suggest that VCS clips may provide a suitable alternative to conventional suture in pediatric aortic vascular surgery.

Vascular Closure Stapler Clip Anastomosis Decreases Aortic Cross-Clamping Time Compared to Interrupted Nonabsorbable and Running Absorbable Sutures in Growing Pigs

The latest generation in titanium clip application systems, the vascular closure staples (VCS) system avoids intimal lesions and therefore minimizes the subsequent hyperplastic reaction, while at the same time enhancing distensibility and vascular growth. Moreover, VCS clips allow the surgeon to perform vascular anastomosis easily and faster than conventional suture. This system may become the option of choice for vascular reconstruction in pediatric surgery where, as in the case of aortic and transplant surgery, decreasing vascular occlusion times may influence the outcomes. The aim of this study was to determine whether VCS metallic clips would allow shorter anastomosis times than conventional interrupted polypropylene or running Dexon suturing in end-to-end anastomosis performed in the abdominal aorta of young pigs. Twenty-four domestic swine, 45 days old, were used for this study. All animals were subjected to an end-to-end anastomosis in the abdominal aorta using VCS clips, interrupted polypropylene, or running Dexon suture. Aortic cross-clamping time was significantly shorter in the VCS clips group (4.02 +/- 0.72 min), compared to interrupted polypropylene (21.89 +/- 1.93 min) or running Dexon (9.82 +/- 3.97 min) suture. VCS clips are easy to use, and therefore may aid surgeons to significantly decrease the time needed for performing an end-to-end anastomosis in the abdominal aorta, thus decreasing cross-clamping time when compared to interrupted polypropylene or running Dexon sutures.

Vein and artery growth after anastomosis with vascular closure staple clips vs interrupted polypropylene suture: application in pediatric vascular surgery

BACKGROUND/PURPOSE

Alternatives are still being sought in vascular surgery to address the problem of arrested growth after anastomosis in growing vessels, and opinions differ widely regarding the most suitable technique. This study compared vascular growth and permeability after anastomosis using the latest-generation vascular closure staple (VCS) system and the conventional suture technique to ascertain which approach yielded better results.

METHODS

Thirty 55-day-old lambs underwent end-to-end anastomosis of the carotid artery and jugular vein. Serial ultrasonography and angiography were carried out over the ensuing 6-month growth period, after which lambs were euthanized.

RESULTS

Both VCS clips and polypropylene suture allowed longitudinal and transverse vessel growth; however, longitudinal growth was significantly greater in clip-closed vessels than in either sutured or untreated vessels.

CONCLUSIONS

The results obtained for vascular growth and permeability suggest that VCS clips may provide a suitable alternative to conventional suture in pediatric vascular surgery.

Randomized clinical trial of continuous sutures or non-penetrating clips for radiocephalic arteriovenous fistula

Background

Despite several modifications to the original design, patency rates of radiocephalic arteriovenous fistulas have changed little since the first report in 1966. The use of non-penetrating clips for vascular anastomosis on the outcome of such fistulas was studied.

Methods

Between January 2000 and August 2003, 107 primary radiocephalic fistulas were constructed in 98 patients. The vascular anastomoses were performed at random with either sutures (n = 56) or clips (n = 51).

Results

Although there were trends for better primary and primary assisted patency of clipped fistulas, the differences were not statistically significant. The 6-month primary patency rate was 61 per cent with sutures and 69 per cent with clips (P = 0·393). The mean(s.d.) primary patency was 315(306) and 285(285) days for clipped and sutured fistulas respectively. With regard to secondary patency, clipped fistulas were better (P = 0·009). The mean(s.d.) secondary patency was 435(376) and 344(316) days for clipped and sutured fistulas, respectively. There were no significant differences in flow characteristics, number of revisions or other morbidity.

Conclusion

This randomized clinical trial provided further evidence that the use of vascular clips may improve the patency rate of radiocephalic arteriovenous fistulas for haemodialysis.

Five years' world experience with nonpenetrating clips for vascular anastomoses

BACKGROUND

A new sutureless technique has been introduced clinically to facilitate the process of vascular reconstruction and improve patency. The Vessel Closure System (VCS) is nonpenetrating, creates an elastomeric everted anastomosis, and is easily and reproducibly applied. The objective of this report is to review the published world experience that has accrued regarding these clips with attention to the assets, liabilities, and pitfalls associated with the new technology.

DATA SOURCES

Medline search and manual cross-referencing were performed, after which 61 original articles were identified on the use of VCS clips for vascular anastomoses.

RESULTS

Advantages of the clips compared with sutures include the technical ease of application, the reduced anastomotic time, the superior hemodynamics, and the improved healing pattern of the anastomosis. Disadvantages include the potential problems in atherosclerotic vessels, lack of prospective randomized long-term follow-up, and initial costs. The best clinical results have been achieved in microvascular repair, as well as with vascular access and transplantation surgery.

CONCLUSIONS

The VCS clip technology has become an accepted vascular anastomosing technique, which in future could lead to the use of clips as a standard approach and the use of sutures only in case of severe atherosclerosis and other circumstances in which vessel edges are difficult to evert.

A prospective evaluation of interrupted nitinol surgical clips in arteriovenous fistula for hemodialysis

BACKGROUND

The use of a self-closing nitinol surgical clip (Coalescent Surgical U-Clip) is a novel technique of creating an interrupted vascular anastomosis, which also eliminates the knot tying associated with a conventional vascular anastomosis. The purpose of this study was to compare the clinical outcome of arteriovenous fistulae (AVF) for hemodialysis as constructed using interrupted U-Clip devices and conventional continuous polypropylene sutures.

METHODS

We prospectively studied the clinical course of 132 patients (149 access) undergoing either forearm autologous arteriovenous fistula (FAVF, n = 69) or upper arm autologous arteriovenous fistula (UAVF, n = 80) or creations during a 39-month period. Among the FAVF, U-Clips and polypropylene sutures were used in 37 and 32 anastomoses, respectively. Among the UAVF, U-Clips and polypropylene sutures were used in 41 and 30 anastomoses, respectively. Primary patency, complication, and maturation rates were analyzed.

RESULTS

Clipped FAVF had an improved maturation rate at 6 weeks (32 of 37, 86%) when compared with sutured FAVF (22 of 32, 69%, P <0.05). There was no difference in the maturation rate among UAVF constructed with either U-Clips or sutures (88% versus 87%, not significant). The primary patency rates at 12, 24, and 36 months were 91%, 84%, and 75% for the clipped FAVF; and 83%, 74%, and 61% for the sutured FAVF (P <0.05) There was no difference in the patency rate of UAVF constructed with either U-Clips or polypropylene sutures at either 12, 24 or 36 moths (91%, 80%, and 75% versus 83%, 77%, and 69%, respectively).

CONCLUSIONS

The U-Clips are a viable alternative to sutures for creating vascular anastomosis. It provides a improved maturation and patency rates when compared with the conventional sutured AVF in the forearm. The clinical benefit of the U-Clips may be due in part to the improved compliance created by the interrupted anastomotic technique.

A multicenter study of permanent hemodialysis access patency: beneficial effect of clipped vascular anastomotic technique

OBJECTIVE

There is an urgent and compelling need to reduce the morbidity and expense of maintaining hemodialysis vascular access patency. This large, long-term, retrospective, multicenter study, which compared access patency of autogenous arteriovenous fistulas (AVF) and synthetic bridge grafts (AVG) created with conventional sutures or nonpenetrating clips, was undertaken to resolve conflicting results from previous smaller studies.

DESIGN

Patency data for 1385 vascular access anastomoses (clipped or sutured) was obtained from 17 hospitals and dialysis centers (Appendix). Five hundred eighteen AVF (242 clip, 276 suture) and 827 AVG (440 clip, 384 suture) were analyzed. Statistical comparisons were made with Kaplan-Meier survival analysis, log-rank test, two-sample t test, and X(2) test. The Cox proportional hazards model was used to confirm Kaplan-Meier analysis.

RESULTS

Access patency (primary, secondary, overall, and intention to treat) was significantly improved in access anastomoses constructed with clips. In the intention-to-treat group, primary patency at 24 months was 0.54 for clipped AVF and 0.34 for sutured AVF, and was 0.36 for clipped AVG and 0.17 for sutured AVG. At 24 months, primary patency rate for AVF successfully used for dialysis was 0.67 for clips and 0.48 for sutures, and for AVG was 0.39 for clips and 0.19 for sutured constructs. Interventions necessary to maintain patency were significantly fewer in clipped anastomoses.

CONCLUSION

Replacing conventional suture with clips significantly reduces morbidity associated with maintaining permanent hemodialysis vascular access. This beneficial effect may be due to the biologic superiority of interrupted, nonpenetrating vascular anastomoses.

Improving the patency of vascular bypass grafts: the role of suture materials and surgical techniques on reducing anastomotic compliance mismatch

BACKGROUND

compliance mismatch is an important factor in the development of myointimal hyperplasia in both coronary and vascular anastomoses. This mismatch may be reduced by the use of newer suture materials and techniques. This review discusses the current techniques and materials used to date in generating anastomoses in both coronary and vascular applications and to correlate these with the degree of inherent compliance achieved.

METHODS

PubMed, ISIS, CAS and PAS database searches were performed. Other articles were cross-referenced.

RESULTS AND CONCLUSION

continuous suture is still the most used technique in both cardiac and vascular surgery for the generation of anastomoses due to the reduced time and improved haemostasis. However, continuous suture results in a greater compliance mismatch than the interrupted technique. Vein cuffs and patches improve compliance and transmission of pulsatile blood flow and offer improvement of graft patency. Alternative to sutures are biological glue, clips and laser generated solders all of which have shown promising results, but further work is required before they become applicable for routine use.

Vascular closure staples reduce intimal hyperplasia in prosthesis implantation

BACKGROUND

Vascular surgery, like the various other surgical specialities, has seen an increasing demand toward faster and more minimally invasive procedures. One such need is to create a reliable vascular anastomosis that is faster, easier and less damaging to the tissue. The vascular closure staples (VCS*) device provides such characteristics but, to date, no studies have investigated its effectiveness in reducing intimal hyperplasia when used for vascular prosthesis implantation. The present study evaluated its effectiveness compared with suturing of a graft in vascular prosthesis implantation.

METHODS

Twelve female Merino sheep underwent gelatin sealed Dacron patch graft implantation into the left and right common carotid artery. Grafts were randomly allocated so that one carotid artery and graft was anastomosed using sutures and the other with VCS*. The two techniques were compared for operation time, clip/suture numbers and blood loss during the implantation procedure. After a 4-week period, the sheep were killed and the grafts were harvested for intimal hyperplasia (IH) assessment.

RESULTS

There was a significant reduction in the amount of IH seen in the VCS* group (mean +/- SD: 0.278 +/- 0.079 mm2/mm) when compared with the sutured group (0.575 +/- 0.331 mm2/mm) (P < 0.05). There was also significant reduction in anastomosis time (mean +/- SD: 14 +/- 4.4 min) and fewer points of contact (23 +/- 1.4) using the VCS* compared with suturing (22 +/- 3.2 min, P < 0.01; 27 +/- 3.3, P < 0.05, respectively).

CONCLUSIONS

In this model, the VCS* shows several distinct advantages over suturing with significant time saving at operation and, most importantly, the reduction of IH seen at 1 month.

Preservation of endothelial integrity and function in experimental vascular anastomosis with non-penetrating clips

BACKGROUND

Vascular repair with sutures is associated with disruption of the endothelial lining and subsequent thrombus formation on the intraluminal lesions. This experimental study was designed to determine whether the use of non-penetrating clips improved endothelial preservation.

METHODS

In ten female pigs, 25-mm arteriotomies were made in both carotid arteries. The arteriotomies were repaired with jugular vein patches. On the left side, the repair was done with 1.4-mm titanium clips, and on the right side with two running 6/0 polypropylene sutures. Next, the aorta was divided and subsequently repaired with 2-mm clips in five of these pigs, and with two running 5/0 polypropylene sutures in the remaining five pigs. Endothelial function was studied at the anastomotic site in the carotid arteries by determination of endothelium-dependent and -independent relaxatory responses. Morphometric examination of the carotid arteries and inspection of the aortic endothelium were performed by means of scanning electron microscopy.

RESULTS

Maximal endothelium-dependent relaxation to adenosine 5'-diphosphate was less in sutured than in clipped carotid arteries (P < 0.05), while there was no difference in maximal endothelium-independent relaxation to sodium nitrite. This result in clipped carotid arteries was not accompanied by less intimal hyperplasia. Screening of the aortic anastomotic line showed better preservation of endothelial architecture after clip anastomosis. Mean cross-clamp time for carotid patch repair was significantly less when using clips than with sutures.

CONCLUSION

The use of non-penetrating clips for vascular anastomoses preserved endothelial function and structural integrity better than running sutures, although the degree of intimal hyperplasia was similar.

Arcuate-legged nonpenetrating vascular closure staples (VCS): early experience

Vascular closure staples (VCS) provide a novel technique for fashioning vascular anastomoses, allowing a single operator to perform suture-less anastomoses. They may be used primarily or in an adjuvant role. When VCS are compared to a running suture, advantages include the avoidance of intimal damage, platelet aggregation and intimal hyperplasia at the anastomotic suture line, and a shorter time taken to complete the anastomosis. We report our early experience using VCS in an array of vascular anastomoses and conclude that VCS are a useful addition to the vascular surgeon's armamentarium. They help to decrease the time taken to construct an anastomosis, and are particularly useful in an adjuvant setting, complementing conventionally placed sutures.

Patency and flow characteristics using stapled vascular anastomoses in dialysis grafts

BACKGROUND

Improving patency of hemodialysis grafts is challenging. Vascular stapling creates nonpenetrating anastomoses, possibly decreasing intimal hyperplasia. We investigated patency and flow characteristics of stapled hemodialysis grafts.

METHODS

Eighty-six grafts (41 stapled, 45 sewn) were placed in 84 patients (prospective, randomized). The groups had comparable demographics.

RESULTS

Thirty-six grafts were functioning at the study endpoint. Complications in both groups were similar. The primary patency (stapled, 342 days versus sewn, 382 days; P = 0.67) and secondary patency (stapled, 513 days versus sewn, 507 days; P = 0.76) had no significant differences. Flow characteristics were similar between the groups. Thrombectomies per patient-year were 1.01 for stapled grafts and 1.12 for sewn grafts (not significant). Stapling decreased the average operating time by 4.5 minutes.

CONCLUSIONS

Stapled and sewn anastomoses have similar primary and secondary patency and flow characteristics, with minimal operative time differences. Stapled anastomoses are safe but had no advantage over sewn anastomoses in this study.

Analysis of nonpenetrating clips versus sutures for arterial venous graft anastomosis

The use of nonpenetrating clips (NPC) for vascular anastomosis is quickly becoming accepted. Studies attest to decreased anastomotic time, comparable patency rates, and decreased blood loss. Few human studies on the use of NPC have been done to date. The purpose of this study was to evaluate primary patency rates, operative time, and complications associated with NPC compared to those with standard sutures for arterial venous graft (AVG). We retrospectively reviewed the clinical course of 82 patients with a mean age of 45 years (range, 22 to 87) from February 1996 to July 1999. All patients underwent upper extremity AVG construction. The procedures were performed at a single institution, by a single, well-experienced surgeon who has extensive experience with NPC. Primary patency rates, operative time, and complications were analyzed. Overall thrombotic incidence of AVG when NPC were used (27/48, 56%) was similar to that of sutures (17/34, 50%). Thrombotic incidence within the first year was similar as well (23/48, 48% and 13/34, 38%). The mean time to primary thrombosis was similar in both groups (6.9 and 6.8 months). The operative time required to construct an AVG with NPC (83 min) was significantly less than that with sutures (96 min) (p = 0.015). There was no significant difference in incidence of graft infection or pseudoaneurysm formation. NPC for AVG reduced operative time and resulted in primary patency and complication rates similar to those associated with use of sutures. The mean time to primary thrombosis was similar for both groups. Our findings suggest an intimal hyperplastic response of a similar nature resulting in thrombosis of both NPC and sutured AVGs.