Arterial and venous repair with vascular clips: comparison with suture closure

Light-Activated Vascular Anastomosis

Background. There have been few advances in technique since vascular anastomosis was performed with silk suture on a curved needle in 1902. This technique results in disruption of the endothelium with exposed intraluminal suture, both of which may lead to thrombocyte aggregation, intimal hyperplasia, and vascular stenosis. A variety of alternative techniques have been explored, with limited success. Photochemical tissue bonding (PTB) is a light-activated methodology of rapidly cross-linking tissue interfaces at the molecular level. Herein, we describe a new technique for anastomosis of venous interposition graft in an ovine model of femoral artery bypass utilizing PTB. Methods. Polypay specific pathogen free sheep (n = 5; 40-45 kg) underwent femoral artery bypass utilizing saphenous vein. The femoral artery was transected and reversed saphenous vein was implanted as an interposition graft. The proximal anastomosis was created as a vein-over-artery cuff utilizing PTB, and the distal anastomosis was created with standard interrupted 8-0 polypropylene suture. Four weeks post-index operation, femoral angiogram was performed to evaluate patency, tortuosity, and luminal diameter. All bypass grafts were harvested and longitudinal and transverse histological sections from the proximal anastomosis were analyzed. Results. The PTB anastomoses (n = 5) were immediately watertight and patent. All animals survived the 28-day study duration. Angiography revealed patent grafts with no aneurysm or stenosis (n = 5). Histologic examination revealed integration of the venous endothelium with the arterial adventitia. Conclusion. Photochemical tissue bonding creates an immediate strong, watertight vascular anastomosis that can withstand physiologic arterial pressure and remains patent at 28 days without the need for intraluminal suture.

Non-suturing microvascular anastomosis in maxillofacial reconstruction- a comparative study

AIM

The aim of the study is to compare the advantages and disadvantages of non-suturing anastomotic methods over conventional microsuturing for microvascular venous anastomosis.

MATERIALS AND METHODS

All patients reporting to the institute for hard and soft tissue reconstruction (Primary/secondary) were enrolled in the study. Patients with systemic comorbidities, peripheral vascular diseases, or anatomical aberration of the indicated donor site were excluded from the study. The patients selected for the study were randomly allocated to five groups of different techniques of venous anastomosis, namely Group I (conventional microsuturing), II (fibrin sealant reinforced microsuturing), III (couplers), IV (staplers), V (Laser Assisted Vascular Anastomosis (LAVA)). Intraoperative anastomotic time, flap ischaemic time, patency and leakage were the parameters that were assessed for all five groups.

RESULTS

80 Patients were randomly allocated to five groups and each group comprised 16 patients. The mean ischaemic time and standard deviation of Group I and Group II were 256.19 ± 10.622 min and 255.19 ± 11.083 min, and for groups III, IV, and V were 193.38 ± 9.972 min, 139.06 ± 6.413 min, and 139.31 ± 6.364 min respectively (p < 0.001). Mean anastomotic time and standard deviation were 19.813 ± 1.5366 min in Group I and 20.281 ± 1.6514 min in Group II. The non-sutured anastomosis groups III, IV, and V showed a mean anastomotic time of 5.375 ± 0.9876 min, 4.175 ± 0.7664 min, and 3.856 ± 0.867 min respectively (p value < 0.001). In Groups I and II, 18.8% of patients had delayed patency and in Groups III, IV and V, immediate patency was observed in all subjects (p value 0.030). In Groups I and II, 18.8% and 6.3 % of patients respectively had leakage, whereas all patients in Groups III, IV, V had no leakage from the anastomotic site (p value 0.119).

CONCLUSION

Based on the results of the study, non-suturing techniques should be preferred over microsuturing technique whenever appropriate for venous anastomosis.

3D-Printed Sugar-Based Stents Facilitating Vascular Anastomosis

Microvascular anastomosis is a common part of many reconstructive and transplant surgical procedures. While venous anastomosis can be achieved using microvascular anastomotic coupling devices, surgical suturing is the main method for arterial anastomosis. Suture-based microanastomosis is time-consuming and challenging. Here, dissolvable sugar-based stents are fabricated as an assistive tool for facilitating surgical anastomosis. The nonbrittle sugar-based stent holds the vessels together during the procedure and are dissolved upon the restoration of the blood flow. The incorporation of sodium citrate minimizes the chance of thrombosis. The dissolution rate and the mechanical properties of the sugar-based stent can be tailored between 4 and 8 min. To enable the fabrication of stents with desirable geometries and dimensions, 3D printing is utilized to fabricate the stents. The effectiveness of the printed sugar-based stent is assessed ex vivo. The fabrication procedure is fast and can be performed in the operating room.

Rapid M1 Hemoclips Arteriotomy Repair After Emergency Coil Embolectomy

BACKGROUND

The vascular closure staple clips have been studied in animal models and shown to have comparable results with sutured repair when it comes to the healing process, degree of vessel narrowing, and risk of thrombosis. However, they are clearly superior when the speed of application is taken into account, and they were clinically used in many vascular repair processes. Nevertheless, their usefulness in intracranial vascular surgery has not been described.

OBJECTIVE

To describe the usefulness of hemoclips in fast and efficient repair of medium-sized and large intracranial vessels.

METHODS

Two female patients diagnosed with giant symptomatic cavernous sinus aneurysms were undergoing elective endovascular procedures that were complicated by the dislodgement of coils into the M1 segment of the middle cerebral artery. Both patients were treated performing M1 arteriotomies and coil embolectomy. To avoid prolonged temporary occlusion in the M1 perforator's territory, the arteriotomies were repaired using microhemoclips in less than 10 min with re-establishment of flow.

RESULTS

In both patients, flow was re-established in the M1 segments. In 1 patient, the coils extended to the temporal M2 causing intimal injury and leading to diminished flow. M1 segments in both patients were patent on later angiographic studies.

CONCLUSION

We describe the advantage of emergent cerebrovascular arteriotomy and embolectomy in a rapid repair process that helped avoid massive ischemic injury. We believe this technique should be added to the armamentarium of neurosurgical cerebrovascular options.

Venous Repair with Vascular Clips and Conventional Suture: A Comparative Experimental Study

Objectives:

The non-penetrating Vascular Clip System (VCS) was tested experimentally and compared with the conventional suture method on the venous system.

Materials and Methods:

In five pigs, 30 transverse venotomies were carried out in the jugular and renal veins, and vena cava. Fifteen venotomies were reconstructed using autosuture clips and 15 using the standard needle and suture method. Eight weeks later, following phlebography, the specimens were examined macro- and microscopically.

Results:

For both methods, the veins remained patent; however, significant stenosis of 8.9% (95% CI: 0.6–17.1) for the renal vein and 8.5% (95% CI: 1.2–15.7) for the vena cava occurred when the suture technique was used. The intima to media height ratio remained the same. The anastomosis time with the clips was significantly shorter ( p<0.05), while the endothelium remained intact without any hyperplasia or inflammatory changes, which are usual findings of the suture technique.

Conclusion:

Early and mid-term results show that the VCS clipped anastomotic technique seems to be effective and acceptable for venous reconstructions.

Utility of nonpenetrating titanium clips for dural closure during spinal surgery to prevent postoperative cerebrospinal fluid leakage

OBJECT

The nonpenetrating titanium clip has been successfully used in peripheral arterial bypass surgery. The purpose of this study was to evaluate the leakage pressures and patterns of nonpenetrating titanium clips using a simple model that mimicked spinal surgery. In addition, the authors describe their surgical experience with these clips and the follow-up results in 31 consecutive patients.

METHODS

The authors compared nonpenetrating titanium clips and expanded polytetrafluoroethylene (ePTFE) sutures in relation to the water pressure that could be tolerated by sutured ePTFE sheets, and the leakage pressure patterns were determined. The changes in leakage pressures at 5 minutes, 30 minutes, and 12 hours were examined when the clips and sutures were used in combination with the mesh-and-glue technique in an in vitro study. Thirty-one patients underwent spinal intradural procedures using nonpenetrating titanium clips to suture the dura maters using the meshand-glue technique, involving fibrin glue and polyglycolic acid-fibrin sheets.

RESULTS

A significant difference was apparent between the ePTFE suture group and the nonpenetrating titanium clip group, with the latter showing a leakage pressure that could be sustained and was 1508% higher than that of the former (p = 0.001). In relation to leakage patterns, the nonpenetrating titanium clips did not make any suture holes in the ePTFE sheet and fluid leakage occurred between the clips, whereas fluid leakage was associated with the pressure elevation that occurred at the suture holes made by the ePTFE sutures. Of the 31 patients who underwent spinal intradural procedures using nonpenetrating titanium clips, 1 (3.2%) experienced cerebrospinal fluid (CSF) leakage postoperatively. No other complications-for example, allergic reactions, adhesions, or infections--were encountered.

CONCLUSIONS

The interrupted placement of nonpenetrating titanium clips enables dural closure without creating any holes. These clips facilitate improvements in the initial leakage pressure and reduce postoperative CSF leakage following spinal surgery. The authors conclude that it is very beneficial to suture the spinal dura mater using nonpenetrating titanium clips given the anatomical characteristics of the spinal dura mater and the fact that the clips do not create suture holes.

REPAIR OF AN ALARMING INTRAOPERATIVE INTRACAVERNOUS CAROTID ARTERY TEAR WITH ANASTOCLIPS: TECHNICAL CASE REPORT

OBJECTIVE

Surgical treatment of an intracavernous carotid aneurysm (ICCA) is difficult because of the close relationship to bone, dura, and neurovascular structures. Intraoperative rupture of an ICCA is challenging, especially if the site of rupture is at the base of the aneurysm. We present a case of intraoperative rupture of an ICCA caused by clinoidectomy. We repaired it by using a single-clamp applicator (AnastoClip Vessel Closure System, 1.4 mm; LeMaitre Vascular, Burlington, MA).

CLINICAL PRESENTATION

In April 2007, a 40-year-old woman underwent neurosurgical treatment at another institution for a ruptured basilar bifurcation aneurysm, with good recovery. Digital subtraction angiography performed at this time showed the presence of left internal carotid artery aneurysms, 1 at the anterior wall of the paraclinoidal segment and 1 at the lateral wall of the intracavernous segment. In February 2008, the patient was referred from outside Finland to our department for microsurgical treatment of both aneurysms.

TECHNIQUE

A lateral supraorbital approach was used, and during extradural removal of the anterior clinoid with a rongeur, the ICCA ruptured. The base of the intracavernous aneurysm was involved in the rupture, and we used a single-clamp applicator to repair the internal carotid artery. Intraoperative digital subtraction angiography, indocyanine green video angiography, and Doppler ultrasonography showed a good flow in the artery. The paraclinoid aneurysm was uneventfully clipped during the same intervention.

CONCLUSION

Intraoperative rupture of ICCA was repaired quickly and effectively by using a single-clamp applicator. Our case and experimental data from other microsurgical vascular experiences suggest that the future of intracranial vessel repair/anastomoses will be using microclips and other simpler devices more, allowing the neurosurgeon to perform fast and effective vessel repair.

Trial of new vascular clips for aortic anastomosis in a canine model

OBJECTIVES

We created a new vascular clip designed for aortic surgery. The purposes of this investigation were to examine surgical applicability in a clinically relevant aortic replacement model and to assess biomechanical strength of the clipped anastomosis and serial histologic changes in the clipped anastomotic site.

METHODS

Twenty-one beagles underwent descending thoracic aortic replacement. Distal anastomosis was performed with the new clips, mimicking the cuffed anastomosis technique, and proximal anastomosis was carried out by conventional suture anastomosis. Tissue specimens of the anastomotic sites were harvested at 1, 3, 6, and 12 months postoperatively for examination.

RESULTS

There was no significant difference in the time required to carry out clip anastomosis (12.2 +/- 1.3 minutes) and suture anastomosis (13.7 +/- 0.9 minutes; P = .38). Neither type of anastomotic site was disrupted by raising the intraluminal pressure to 280 mm Hg. Microscopically, the areas of aortic wall compressed by vascular clips appeared as hyalinized areas adjacent to surrounding collagen fibers, with no significant infiltration of inflammatory cells. Identical histologic changes were observed at the site of the sutured anastomosis. The media at the clipped anastomosis site was significantly thinner than that at the sutured anastomosis site at 1 month after the operation. However, there was no significant difference in the thickness of the media at 3 months.

CONCLUSIONS

The new vascular clips were effective in this clinically relevant model, with appropriate biomechanical strength, and the anastomotic sites underwent similar histologic changes to those observed after suture anastomosis.

Combat casualty care research: from bench to the battlefield

Hemorrhagic shock is the leading cause of death in civilian and combat trauma. Effective hemorrhage control and better resuscitation strategies have the potential of saving lives. The Trauma Readiness and Research Institute for Surgery (TRRI-Surg) was established to address the core mission of the Uniformed Services University, "Learning to Care for Those in Harm's Way," by conducting research to improve the outcome of combat casualties. This article highlights the salient achievements of this research effort in the areas of hemorrhage control, resuscitation, design and testing of devices, and some novel concepts such as the use of profound hypothermia. The impact of these basic science research findings on changes in military medical care and outcome of injured soldiers is also described.

Vascular closure staples for portal vein reconstruction in living-donor liver transplantation

BACKGROUND

Portal vein reconstruction is still a crucial problem in living-donor liver transplantation. Vascular closure staples (VCS) have been applied for small peripheral and large vessels because of the technical ease with which they can be employed. We describe here our experience with portal vein reconstruction in living donor-liver transplantation and compare VCS with conventional sutures in portal vein reconstruction.

METHODS

The anastomosis between the donor portal vein and recipient portal vein or the right external iliac vein graft was created using either VCS or conventional sutures.

RESULTS

The stenotic ratios were .51 +/- .15 and .79 +/- .25 for the conventional sutures and VCS, respectively. The stenotic ratio was significantly lower in VCS compared with conventional sutures.

CONCLUSIONS

VCS compared with conventional sutures has the advantage of low risk of anastomotic stenosis.

Vascular Closure Stapler Clips Versus Polypropylene Sutures in End-to-End Anastomoses of Growing Arteries and Veins

Alternatives are still being sought in vascular surgery to avoid the complications caused in growing vessels by the various suture techniques and materials currently in use. A major complication is arrested growth following anastomosis. Opinions differ widely regarding the best approach to this problem, and research is currently underway at our center on the latest generation of clip appliers (vascular closure stapler, or VCS) and their potential application as an alternative to the conventional suture technique in pediatric vascular surgery. This study compared vascular growth and reendothelialization following anastomosis of growing arteries and veins using VCS clips versus the conventional interrupted polypropylene suture technique. 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 the lambs were euthanized. Gross examination of the anastomosis site was followed by histologic examination involving light microscopy, immunohistochemical techniques, and transmission electron microscopy. Although both VCS clips and polypropylene sutures allowed transverse vessel growth, the clips did not penetrate the intima and thus provided enhanced reendothelialization. The satisfactory results obtained here, as in earlier studies, increasingly point to VCS clips as the method of choice 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.

Non-suture methods of vascular anastomosis

BACKGROUND

The main aim of performing a vascular anastomosis is to achieve maximal patency rates. An important factor to achieve that goal is to minimize damage to the vessel walls. Sutures inevitably induce vascular wall damage, which influences the healing of the anastomosis. Over time, several alternatives to sutures have become available.

METHODS

A Medline literature search was performed to locate English, German and French language articles pertinent to non-suture methods of vascular anastomosis. Manual cross-referencing was also performed and many historical articles were included.

RESULTS AND CONCLUSION

The non-suture techniques can be categorized into five groups based on the materials used: rings, clips, adhesives, stents and laser welding. With all these techniques a faster and less traumatic anastomosis can be made compared with sutures. However, each device is associated with technique-related complications. As a consequence, suturing continues to be the standard approach. The disadvantages of the non-suture techniques include: rigidity and a non-compliant anastomosis with rings; toxicity, leakage and aneurysm formation with adhesives; early occlusion with stents; cost, reduced strength in larger-sized vessels and demand for surgical skills with laser welding. Further refinement is needed before widespread adoption of these techniques can occur. Clips, however, may be particularly promising but long-term evaluation is required.

Primary sciatic nerve repair using titanium staples

The primary epineural repair of human peripheral nerves is most often achieved using non-absorbable microsutures, which can elicit a foreign-body reaction. We describe a new system for neural-tissue approximation, consisting of non-penetrating vascular closure staples (VCS) applied to the epineurium. These clips were initially developed for use in microvascular anastomosis, with no knowledge of their effectiveness in neural-tissue approximation. We compare the efficacies of VCS clips and monofilament nylon microsutures in the repair of transected sciatic nerves in 36 adult Sprague Dawley rats (18 treated with 9/0 sutures and 18 treated with VCS clips). In the rat, regeneration starts by day 5, and is well advanced by 4 weeks. To assess the overall repair success, the site of injury, after perfusion fixation, was harvested at 5, 7 and 30 days. The two methods were compared in terms of operative time, the degree of self-mutilation (autotomy), the macroscopic specimens in vivo and the microanatomical continuity through the repair site. Continuity was studied by using PGP-9.5-labelled cryosections and fluorescent secondary antibodies to visualise axonal regeneration. Clip repair was significantly faster in the VCS group (mean +/- s.e.m. = 7.09 +/- 0.36 min versus mean +/- s.e.m. 11.56 +/- 0.51 min in the sutured group) and an equal and minimal degree of autotomy was observed. Macroscopically, all 36 nerves were in continuity and free from neuroma. The use of VCS clips resulted in equivalent visualised regeneration across the repair site at each time point. We believe the use of VCS clips to be a faster and comparable alternative to non-absorbable sutures in primary nerve repair in this experimental model.

End-to-end anastomosis in growing vessels using a novel suturing technique: VCS metallic staples

For pediatric transplants, a suturing technique is needed that allows the vessel to grow along with better healing of the anastomosis, through eliminating exogenous and thrombogenic material in the intimal side, thus minimizing the risk of vascular stenosis. In this study, 12 55-day-old lambs were subjected to end-to-end anastomosis of the right carotid artery and external jugular vein using vascular closure staple (VCS) clips (the vessels from the left side served as controls). Animals were followed up with duplex ultrasound. After 6 months, angiography was performed and animals were euthanized for microscopic study of the vessels. Duplex ultrasonography and angiography showed all vessels to be patent, with no flow disturbances and no stenosis at the anastomotic site at 6 months. Stenotic segments caudal to the anastomosis site were seen in two veins. No significant changes were seen macroscopically in any of the veins, whereas one of the arteries developed a pseudoaneurysm at the anastomotic site. Histological structure was normal in all the studied veins. Arteries showed different degrees of modifications that did not affect patency or flow in any case. Measurements taken after 6 months confirm that this technique allows the vessel to grow. This technique may be useful in vascular pediatric surgery.

Numerical study of hemodynamics and wall mechanics in distal end-to-side anastomoses of bypass grafts

The development and progress of distal anastomotic intimal hyperplasia seems to be promoted by altered flow conditions and intramural stress distributions at the region of the artery-graft junction of vascular bypass configurations. From clinical observations, it is known that intimal hyperplasia preferentially occurs at outflow anastomoses of prosthetic bypass grafts. In order to gain a deeper insight into post-operative disease processes, and subsequently, to contribute to the development of improved vascular reconstructions with respect to long term patency rates, detailed studies are required. In context with in vivo experiments, this study was designed to analyze the flow dynamics and wall mechanics in anatomically correct bypass configurations related to two different surgical techniques and resulting geometries (conventional geometry and Miller-cuff). The influence of geometric conditions and of different compliance of synthetic graft, the host artery and the interposed venous cuff on the hemodynamic behavior and on the wall stresses are investigated. The flow studies apply the time-dependent, three-dimensional Navier-Stokes equations describing the motion of an incompressible Newtonian fluid. The vessel walls are described by a geometrically non-linear shell structure. In an iterative coupling procedure, the two problems are solved by means of the finite element method. The numerical results demonstrate non-physiological flow patterns in the anastomotic region. Strongly skewed axial velocity profiles and high secondary velocities occur downstream the artery-graft junction. On the artery floor opposite the junction, flow separation and zones of recirculation are found. The wall mechanical studies show that increased compliance mismatch leads to increased intramural stresses, and thus, may have a proliferative influence on suture line hyperplasia, as it is observed in the in vivo study.

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.

A comparison of para-anastomotic compliance profiles after vascular anastomosis: nonpenetrating clips versus standard sutures

PURPOSE

Anastomotic compliance is an important predictive factor for long-term patency of small diameter vascular reconstruction. In this experimental study we compare the compliance of continuous and interrupted sutured vascular anastomoses with those using nonpenetrating clips.

METHODS

Both common carotid arteries in nine goats (average weight, 57 +/- 5.7 kg) were transected, and end-to-end anastomoses were constructed with nonpenetrating clips or polypropylene sutures. The latter were applied with both interrupted and continuous techniques. Intraluminal pressure was measured with a Millar Mikro-tip transducer, and vessel wall motion was determined with duplex ultrasound equipped with an echo-locked wall-tracking system. Diametrical compliance was determined. Environmental scanning electron microscopy was performed on explanted anastomoses.

RESULTS

There was a reduction in anastomotic compliance and associated proximal and distal para-anastomotic hypercompliant zones with the use of all techniques. However, compliance loss was significantly less in those anastomoses with clips and interrupted sutures when compared with continuous suture (P <.001). Furthermore, the total compliance mismatch across anastomoses with continuous sutures was significantly greater than those with clips or interrupted sutures (P <.05). The mean time for constructing clipped anastomoses was 5.7 +/- 1.4 minutes, which was significantly less than either continuous (P <.0001) or interrupted sutures (P <.0001). Furthermore, environmental scanning electron microscopy demonstrated minimal intimal damage with good intimal apposition in the clip group.

CONCLUSION

Anastomoses performed with nonpenetrating clips resulted in improved para-anastomotic compliance profiles and reduced intimal damage when compared with those with polypropylene sutures. These benefits may enhance long-term graft patency by reducing the risk of anastomotic intimal hyperplasia.

Non-penetrating Vascular Clips Anastomosis Inhibited Intimal Thickening Under Poor Runoff Conditions in Canine Autogenous Vein Grafts

OBJECTIVE

Late graft failure is still a significant problem, particularly in cases with poor runoff vessels. The main cause of late graft failure is intimal thickening of the anastomotic region. Vascular closure system (VCS) clips may provide ideal anastomosis, since they do not penetrate the wall. Therefore, we examined whether the VCS clips affect intimal thickening under poor runoff conditions in the canine autogenous vein grafts.

METHODS

A canine poor runoff model was prepared at both femoral veins. Four weeks after the first surgical procedure, two groups were established according to the two different methods of anastomosis employed. The right femoral vein graft was performed using polypropylene sutures, conventional surgical anastomosis (control group), while the left femoral vein graft was performed using VCS clips anastomosis (VCS group). Four weeks after grafting, the vein grafts were removed and the intimal thickening of proximal, distal anastomosis and midportion of the vein grafts were examined histologically.

RESULTS

In the control group, flow rate and variation were 26+/-8 ml/min and 51+/-10 dynes/cm(2), respectively. In the VCS group, the flow rate and variation were 23+/-11 ml/min and 44+/-14 dynes/cm(2), respectively. There were no significant differences between the two groups. The average value of intimal thickening of both the anastomotic region and the midportion of the vein graft in the VCS group was significantly inhibited compared to that of the control group. The number of positive cells of masson trichrome stain in the VCS group was significantly less than that of the control group.

CONCLUSIONS

These experiments indicate that VCS clips significantly inhibit intimal thickening under poor runoff conditions in canine autogenous vein grafts to a greater extent compared to suture-constructed anastomosis. One mechanism that may account for the decreased intimal thickening is the inhibition of the expression of transforming growth factor-beta (TGF-beta), because the number of positive cells of masson trichrome stain in the VCS group was significantly less than that of the control group.

Does vascular stapling improve compliance of vascular anastomoses?

Elastic properties of vessel walls are altered by vascular anastomoses. Such alterations may lead to neointimal hyperplasia, which is a common cause of reocclusion following vascular surgery. The severity of paraanastomotic hypercompliant zones and anastomotic compliance drop depend on suturing material and on elastic properties of the anastomotic vessel segments. This study compares paraanastomotic hypercompliance and anastomotic compliance drop when using a new vascular closure system (VCS) and a conventional, continuous suture line in the preparation of end-to-end anastomoses. Compliance of artery-artery, vein-artery, and polytetrafluoroethylene-artery anastomoses was measured in an artificial circulation system at mean pressures of 60, 90, and 120 mm Hg, comparing conventional suturing and the VCS. When using the VCS for vein-artery anastomoses, significantly less postanastomotic hypercompliance was achieved at mean pressures of 60 mm Hg (14.2 +/-3.8% above remote postanastomotic area), compared to suture (55.1 +/-14.8%, p<0.05). At 90 mm Hg, respective values were 11.0 +/-2.3% for VCS and 54.7 +/-10.1% for suture, p<0.01. At 120 mm Hg, in polytetrafluoroethylene-artery anastomoses, the anastomotic compliance drop was significantly less when using the continuous suture line (93.9 +/-1.1% below remote postanastomotic compliance), compared to VCS (97.2 +/-0.2%, p<0.05). Compared to conventional suturing, use of the VCS reduced postanastomotic hypercompliance in vein-artery anastomoses.

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.

Comparison of titanium vascular closure staples with suture repair of the thoracic aorta in swine

OBJECTIVE

Devices that reduce technical difficulty and anastigmatic time when repairing large vessels such as the thoracic aorta would be beneficial. The aim of this study was to determine if titanium vascular closure staples (3 mm) could be safely and quickly applied in the repair of large vessels such as the thoracic aorta.

DESIGN

Through a left thoracotomy in 10 female swine (110 to 130 lb), an interposition graft (14 to 16 mm textile) was placed into the aorta distal to the left subclavian artery. Animals were randomized at the time of repair to either running sutures (n = 5; 6-0 polypropylene) or vascular closure staples (n = 5; 3 mm). The anastomosis was evaluated after 2 months with aortograms, and the aorta was harvested to evaluate healing.

RESULTS

The clamp times (mean +/- SD) were 30.8 +/- 8.2 min for suture repair and 24.8 +/- 5.1 min for vascular closure staple repair (p = 0.2). Anastomosis times were 20. 0 +/- 6.2 min for the suture group and 16.4 +/- 6.4 min for the vascular closure staple group (p = 0.4). Arch aortograms at 2 months revealed no significant difference in luminal narrowing between the two groups. Gross and microscopic examination revealed no thrombosis, well-healed wounds with a continuous intimal layer, and no differences in intimal thickness or inflammation between the two groups.

CONCLUSION

Vascular closure staples were equivalent to sutures in terms of durability, graft patency, and wound healing at 2 months. Vascular closure staples may offer the trauma surgeon a quick and easy alternative when repairing large vessels such as the thoracic aorta.

Arteriotomy closure by glued patch in the porcine carotid artery

BACKGROUND

A thoracoscopic approach to coronary bypass grafting warrants renewed search for facilitated vascular anastomosis methods. We reassessed tissue adhesion, sealing properties, and histotoxicity of iso-butyl-cyanoacrylate, in a simplified anastomosis model.

METHODS

In 12 Dutch landrace pigs, five arteriotomies were made in each carotid artery. The arteriotomies were closed by conventional microvascular suturing or by pericardial patch (Peri-Strips) and iso-butyl-cyanoacrylate. The animals were sacrificed at 2 hours (n = 2), 2 days (n = 5), and 4 weeks (n = 5). The arteries were examined by flow measurement, angiography, and histologic analysis.

RESULTS

The time required to close arteriotomies by conventional suturing was 257 +/- 43 seconds (mean +/- SD) and by glued patch 51 +/- 27 seconds (p < 0.001). In all arteriotomies covered by glued patch, complete hemostasis was obtained. At 2 days and 4 weeks, with both methods the same histologic results were observed. At follow-up, all carotid arteries were patent without stenoses.

CONCLUSIONS

Arteriotomy closure by glued patch was simple, fast, reliable, and without signs of histotoxicity. Adhesives deserve to be reconsidered as an alternative to suturing in closed chest beating-heart coronary surgery.

Nonpenetrating vascular clips for small-caliber anastomosis

In the search for better anastomosing techniques, an improved vascular stapler device (VCS clip applier system(R)) has been introduced. The system uses nonpenetrating clips to approximate everted vessel walls. The objective of this study was to determine the effects of nonpenetrating vascular clips on endothelial wound healing. Aortic end-to-end anastomoses were performed in male Wistar rats. A comparison was made between clipped (n = 12) and conventional hand-sewn (n = 6) anastomoses. Patency rates were verified at different time intervals (after 1, 4, and 8 weeks), after which the anastomotic sites were removed. Morphological evaluation was carried out using scanning electron microscopy. All rats survived the procedure. Closure with clips took less time than closure with conventional sutures, with decreasing aortic clamping times for the clipped procedures during the course of the experiments. Patency rates were 100% in both the "clipped" and "sutured" groups. Microscopic examination showed favorable endothelial healing at the clipped anastomotic sites, with less inflammatory reaction at 1 week, and a more complete endothelial regeneration at 4 and 8 weeks follow-up, as compared with the sutured anastomoses. The clip applier holds the promise of a useful device in anastomosing small-caliber vessels, since clip closure takes less time than suturing, while patency rates are identical, and morphological results are favorable. Training is mandatory to obtain technical skills and to achieve optimal results.

Use of the vascular closure staple clip applier for microvascular anastomosis in free-flap surgery

We report our initial experience using the vascular closure staple clip applier (a nonpenetrating titanium clip applied in an interrupted, everting fashion) for microvascular anastomosis in free-flap surgery. In total, 153 anastomoses were performed in 87 free flaps (174 potential anastomoses) using the vascular closure stapler between October of 1997 and June of 1999. In 66 flaps, both the arterial and venous anastomosis were performed with the clip applier, whereas in 21 flaps only the venous anastomosis was performed using the clips. A total of 146 anastomoses were performed in an end-to-end fashion, and seven were performed end-to-side. Of the 87 flaps there were 53 TRAM flaps, seven bilateral TRAM, five latissimus dorsi, four gastrocnemius, three rectus abdominis, two radial forearm fibula, and four Rubens fat-pad flaps. Seventy flaps were used for breast reconstruction, seven flaps for lower limb reconstruction, four flaps for head and neck reconstruction, and six flaps for chest wall/trunk reconstruction. There were no postoperative anastomotic complications of bleeding, thrombosis, or need for revision (100 percent patency rate), with a significantly reduced time for completion of anastomoses. The clip applier is a safe, reliable method for performing microvascular anastomoses, allowing reduced operating time and possible cost savings in free-flap surgery.

Vascular clips have no significant effect on the cellular proliferation, intimal changes, or peak systolic velocity at anastomoses in rabbit vein grafts

OBJECTIVE

This study compares vascular closure staples (VCSs) with conventional sutures in the rabbit carotid vein graft model to determine whether anastomotic technique affects cellular proliferation, blood velocity, or intimal changes when measured over a period of 3 months postoperatively.

METHODS

Twenty-six New Zealand White rabbits weighing 3.0-3.2 kg underwent interposition of jugular vein grafts in left carotid arteries. Half of the animals had anastomoses performed with small VCSs (n = 13) and half had anastomoses performed with 8-O interrupted polypropylene suture. Animals were allowed to survive for 1 week (n = 4, VCS; n = 4, suture), 2 weeks (n = 4, VCS; n = 4, suture), and 3 months (n = 5, VCS; n = 5, suture). The peak systolic velocity (PSV) at the distal anastomosis was measured after completion of the graft and again at sacrifice in the 3-month survival groups. At sacrifice, sections were taken from the middle and distal end of the vein graft and the distal carotid artery. Vascular cell proliferation was measured using 5-bromo-2'-deoxyuridine labeling and intimal changes were measured using digitized microscopic images.

RESULTS

All 26 grafts were open at the time of sacrifice. PSV at the distal clipped anastomosis was 40.52 cm/s (t = 0) and 34.3 cm/s (t = 3 months, P = 0.31). PSV at the distal sutured anastomosis was 38.30 cm/s (t = 0) and 39.23 cm/s (t = 3 months, P = 0.82). There was no difference between the two techniques at either t = 0 or t = 3 months (P = 0.51 and P = 0.31, respectively). Endothelial cell proliferation and smooth muscle cell proliferation at the anastomosis was highest during the 2 weeks after the procedure, then returned to baseline levels by 3 months. But there was no significant difference between the clipped and sutured groups with respect to vascular cell proliferation postoperatively. The intimal thickness changed significantly in the vein graft at the anastomosis for both the clipped and sutured groups (P = 0.0007 and P = 0.002). But there was no difference when the intimal changes for each technique were compared (P = 0.94).

CONCLUSION

No differences were observed when peak systolic velocity, vascular cell proliferation, and intimal changes were compared between sutured and stapled anastomoses in rabbit vein interposition grafts over a period of 3 months after surgery.

Vascular Clips in Anastomoses of Femoropopliteal Arterial Reconstruction

The vascular anastomoses are usually made with sutures. Some mainly experimental studies have been published about a new method of doing the vascular anastomoses with metal clips. We studied the suitability of vascular closure staple (VCS) clip applier system for making the anastomoses in femoropopliteal and femorotibial arterial reconstruction. During an 11-month period, VCS clips were used in 17 out of 27 patients who were operated due to severe claudication or incipient gangrena of the foot. Altogether 26 anastomoses were made with VCS clips using either great saphenous vein or PTFE graft. The making of anastomosis was easy and reliable. No postoperative bleeding was noticed. All anastomoses were patent 4-6 weeks postoperatively studied by palpation and measured by ankle brachial pressure index (mean 0.96). In Duplex Doppler examination all studied patients had well patent anastomoses on an average 11 months after the operation. With VCS clip applier system, it is possible to do anastomoses in arteriosclerotic arteries like in femoropopliteal reconstructions. This method helps making reliable anastomoses more easily.

Anastomotic tissue response associated with expanded polytetrafluoroethylene access grafts constructed by using nonpenetrating clips

PURPOSE

The gross, light microscopic, and scanning microscopic appearance of arterial and venous anastomoses in expanded polytetrafluoroethylene (ePTFE) access grafts constructed with nonpenetrating clips were compared with that of those constructed with polypropylene suture. We hypothesized that clip-constructed anastomoses would provide controlled approximation of native vessel intimal and medial components with the ePTFE grafts. We further hypothesized that anastomotic healing with clips would involve primarily an intimal cellular response, as compared with suture-constructed anastomoses in which cells within the media and adventitia walls participate.

METHODS

Femoral artery to femoral vein arteriovenous (AV) grafts were constructed in five dogs using 4-mm internal diameter ePTFE graft material. Each animal received one AV graft with anastomoses constructed by using polypropylene sutures in one leg and one AV graft with anastomoses constructed with Vascular Closure System clips in the contralateral leg. Animals were given aspirin for the duration of the study, and grafts were explanted at 5 weeks. At the time of explantation, graft segments were grossly evaluated and then underwent light and scanning electron microscopic analysis.

RESULTS

At the time of explantation, all access grafts were patent. Joining the ePTFE grafts to the native vessels with clips resulted in minimal vessel wall damage. The lumenal contours of the discontinuous approximation were smooth and without gross endothelial disruption. These observations are in contrast to the lumenal compromise and endothelial disturbance associated with the sutured anastomoses. Furthermore, hemostasis was achieved immediately in the clipped grafts, decreasing the incidence of perianastomic hematoma. Finally, cellular reconstitution occurred at the anastomotic cleft in both the sutured and the clipped junctions. The neointima exhibited an endothelial cell lining on the lumenal surface and the presence of alpha-smooth muscle cell actin positive cells within the subendothelial layer.

CONCLUSION

Vascular Closure System clips are a viable alternative to suture for the approximation of ePTFE AV access grafts to native blood vessels. The use of the clips resulted in a more streamlined anastomosis, with decreased vessel wall damage, immediate hemostasis, and a trend toward shorter procedure times.

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

BACKGROUND

A new vascular clipping system (VCS) has been introduced for clinical use. This study was developed to determine whether patency rates and treatment outcomes for anastomoses in hemodialysis access surgery can be improved by the application of this new technology.

METHODS

During a 10-month period, 96 consecutive patients requiring autologous fistula, synthetic fistula, or graft revisions for hemodialysis were prospectively randomized into two treatment groups. Anastomoses were constructed with the VCS in 46 patients and with polytetrafluoroethylene (PTFE) suturing in 49 patients. The procedures were performed in an outpatient setting, at a large medical center, by one surgeon. Time to construct the anastomosis, amount of bleeding from the anastomotic site, and primary and secondary graft patencies were analyzed.

RESULTS

The mean time to construct anastomoses in autologous and synthetic grafts using VCS clips was significantly shorter than with sutures (autologous 14 versus 22 minutes, P = 0.0001; and new grafts 26 versus 30 minutes, P = 0.04). Blood loss was less in anastomoses done with the VCS clip; however, statistical significance was reached only for autologous fistulas (P = 0.0001). At 2-year follow-up, primary and secondary patencies were similar for both the VCS and suture groups with the exception that a statistically significant improvement was found in secondary patency for autologous fistulas when performed with the VCS.

CONCLUSIONS

The VCS clip is easy to use and produces a more rapid anastomosis with less bleeding. Primary and secondary patencies using the VCS clip were equivalent or improved when compared with standard suture. In our experience, no complications have been attributed to the use of the clip technique.

Comparison of Arcuate-Legged Clipped versus Sutured Hepatic Artery, Portal Vein, and Bile Duct Anastomoses

Attempts at improving anastomoses have included the development of stapling techniques. Our purpose was to evaluate arcuate-legged clipped versus standard sutured anastomoses of the hepatic artery (HA), portal vein (PV), and bile duct in a porcine liver transplantation model. Two groups of pigs were studied intraoperatively and 1 day after liver transplantation. A control group underwent sutured anastomosis of PV and HA with polypropylene and of bile duct with polydioxanone (n = 8). An experimental group underwent anastomoses with arcuate-legged clips (n = 8). We analyzed the time to perform anastomosis and flows before and at various time points after anastomosis. In addition, patency and histology of the anastomoses were evaluated 1 day after operation, including a fibrin-thrombosis score, medial injury, and inflammation score. Times to complete HA and PV anastomoses were not different between clipped and sutured groups. However, the time was shorter to complete bile duct anastomosis with clips than with sutures (6.3 ± 1.1 minutes and 13.3 ± 2.0 minutes, respectively). Flows through HA anastomoses were not different between groups, but flow through the PV was higher in clipped compared with sutured anastomosis (P = 0.06). Patency was 100 per cent with no leaks for all three anastomoses in both groups. Histologic data were similar between vascular anastomotic groups. Sutured bile duct anastomoses revealed mild smooth muscle injury in 75 per cent whereas clipped bile duct anastomoses displayed no smooth muscle injury. We conclude that arcuate-legged clipped anastomosis represents a viable option to sutured anastomoses of the PV, HA, and bile duct anastomoses. Bile duct anastomoses were completed in less than half the time and with less tissue damage documented histologically.

Laparoscopic aortofemoral bypass grafting: human cadaveric and initial clinical experiences

PURPOSE

Postoperative complications are mainly related to the surgical trauma derived from the extensive abdominal incision and dissection after a conventional aortofemoral bypass grafting procedure. In an attempt to reduce postoperative complications, a concept of video-endoscopic vascular surgery on the infrarenal aortoiliac artery has been developed. On the basis of our experience with the practicability of video-endoscopic vascular surgery in the pelvic region in an animal study and in a pilot study of human cadavers, the purpose of this report was to describe three different methods that we evaluated on human cadavers and that we partly applied to patients.

METHODS

In this experimental study, three different approaches were used to perform video-endoscopic aortofemoral bypass grafting. We performed an observational trial on human corpses (n = 24) with the transabdominal-retroperitoneal approach (TARA), the extraperitoneal approach (EPA), and the transabdominal left paracolic approach (TAPA). The EPA also was applied to patients with aortoiliac occlusive diseases.

RESULTS

The TARA on cadavers (n = 4) soon was abandoned because it caused a burdensome sliding of the intestine into the operative field adjacent to the renal vessels, particularly in cases with obese subjects. In comparison, the TAPA (n = 6) with right-sided positioning of the patient retained the intestine in the right upper abdomen throughout the procedure. Until a surgeon actually is acquainted with the anatomic landmarks and the laparoscopic preparation technique, the EPA (n = 14) is a challenging procedure that necessitates thorough training. As with the TAPA, the EPA represents a procedure that reveals constant exposure of the operating field, even in cases with obese subjects. In the clinical observational study (n = 7), aortobifemoral bypass grafting was achieved totally laparoscopically with the EPA. The mean operating time was 6.5 hours and ranged from 3 to 10 hours. Blood transfusions were necessary after surgery in three patients (range, 1 to 3 red packed blood cells). One patient, who had had occlusion of the inferior mesenteric artery, died of ischemic colitis at postoperative day 10. The other patients had uneventful postoperative courses with minor wound discomfort.

CONCLUSION

Laparoscopic vascular surgery seems to be a promising procedure to minimize postoperative complications. On the basis of our experience, we do not favor the TARA. Because it necessitates steep Trendelenburg positioning to displace intra-abdominal organs, the TARA is not an appropriate approach, particularly in obese and cardiopulmonary frail cases. Contrarily, the TAPA and the EPA deliver potentially better results in terms of exposing the operative field and thus reducing operating time and perioperative morbidity rates. A prospective cadaveric and clinical trial may be justified to further evaluate the use of these surgical techniques.

Rapid arterial anastomosis with titanium clips

BACKGROUND

The obvious advantages of rapid arterial anastomoses have prompted the continuing search for more rapid anastomotic techniques to complement the standard sutured anastomosis. Nonpenetrating, arcuate-legged titanium vascular closure staple (VCS) clips were initially developed for microvascular anastomoses. The purpose of this study was to compare VCS clips with sutured arterial end-to-end anastomosis in larger vessels.

METHODS

In 6 pigs, transacted iliac arteries were reanastomosed with VCS clips on one side and continuous 6-0 polypropylene suture on the other.

RESULTS

The reconstruction time was 8.4+/-5.2 minutes for clip closure and 12.0+/-6.6 minutes for suture closure (P = 0.033). All vessels were patent half an hour after completing the anastomoses with no signs of early thrombosis.

CONCLUSIONS

Arterial end-to-end anastomosis can be performed more rapidly with VCS clips than continuous sutures, and are potentially useful in situations where the clamp time of the vessel is critical.