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.     

手术缝线携载反义基因预防血管吻合口内膜增生的实验研究

目的：探讨预防血管吻合口内膜增生的新方法。了解手术缝线携载反义基因对吻合口内膜增生的影响。方法：用分别浸泡过反义，正义及错配c-myc基因溶液的保护薇乔缝线行兔颈外静脉间置于同侧颈总动脉的血管吻合。实验动物24只随机分为对照组，反义组，正义组和错配组，每组6只，4周后血管造影观察吻合口通畅情况，同时取材制片显微镜下观察其内膜增生情况，计算机图像分析测量其内膜，中膜厚度及两者比值；内膜，中膜面积及两者比值。结果：所有吻合口通畅，未见闭塞，扩张或动脉瘤，反义组的内膜厚度，内膜／中膜厚度比值及内膜面积，内膜／中膜面积比值较其他组均低（P＜0．05），其他3组间比较差异均无显著意义（P＞0．05）；各组间的中膜厚度及中膜面积间差异无显著意义（P＞0．05），结论：用浸泡过反义 c-myc溶液的保护薇乔缝线进行血管吻合，能有效地抑制血管吻合口内膜增生。     

Experimental laser-assisted end-to-side microvascular anastomosis

The authors present a new technique of end-to-side microvascular anastomosis in a rat carotid artery model, employing a milliwatt CO2 laser. Both carotid arteries were isolated and approximated in an end-to-side fashion by the placement of four 10-0 nylon stay sutures. The milliwatt CO2 laser was used to effect vessel anastomosis between the sutures, using 70-100 mW of power. Animals were killed 8 weeks postoperatively. Angiography of each anastomosis was performed in all animals. All anastomoses were then harvested, and submitted for histological analysis. Anastomotic patency was 100%, both intraoperatively and angiographically. There was no evidence of intravascular thrombus, anastomotic stenosis, or pseudoaneurysm formation. Early in the experiment, some anastomoses showed localized dilatation at the anastomotic site. The histologic changes at the anastomotic site are described. Laser-assisted microvascular anastomosis is a feasible technique, and a potential alternative to conventional suture techniques.     

Methylene blue soldered microvascular anastomoses in vivo.

OBJECTIVES: solders containing chromophores and proteins enhance the strength of lasered anastomoses. Methylene blue (MB) solder anastomoses in vitro are strong but no in vivo work has been reported. We used an MB solder in vivo and studied the effects of two laser powers on patency and histological appearance. DESIGN, MATERIALS AND METHODS: two groups of 15 rabbits had unilateral end-to-end carotid anastomoses (1.5-2.0 mm) formed using three stay sutures and MB solder. Group 1 anastomoses were formed at 5.7 Wcm(-1) and Group 2 at 2.8 Wcm(-1). The vessels were examined at various points by necropsy for patency and gross macroscopic appearance, with subsequent histological examination. RESULTS: group 2 showed patency of 93.3% v 0% ( p<0.001) endothelialisation of 100% v 26.6% ( p<0.001), giant cell formation 0% v 40.0% ( p<0.01), but stenosis was not significantly different (0% v 13.3% p=0.06). Group 2 showed a higher rate of intimal hyperplasia (IH) (66.6% v 20.0% p<0.05) but neither group exhibited thermal injury or aneurysm formation. CONCLUSIONS: laser soldered microvascular anastomoses were formed in vessels of 1.5-2.0 mm with a high degree of patency. A relationship appears to exist between laser power and anastomotic patency. Methylene blue fading has the potential to act as a switch against over exposure and a visual indicator of solder activation.     

End-to-side and end-to-end vascular anastomoses with a carbon dioxide laser

This study was designed to compare anastomoses performed with a carbon dioxide laser and conventional anastomoses performed with 7-0 polypropylene suture. In each of 80 rabbits, the divided left carotid artery was anastomosed by a continuous suture technique and the right carotid was anastomosed with a carbon dioxide laser. In each of 40 additional rabbits, both end-to-end and end-to-side laser anastomoses were performed on the same carotid artery. The laser technique involved the placement of three stay sutures (end-to-end technique) or four stay sutures (end-to-side technique) of 7-0 polypropylene and an everting laser seal at a power level of 65 mW. The 1-year overall patency rate was 98% (78/80) in laser anastomoses, 79% (63/80) in suture anastomoses, and 95% (38/40) in combined end-to-end and end-to-side laser anastomoses. Microscopic findings in laser anastomoses demonstrated degeneration of collagen and protein in the adventitia and media, but much less intimal injury than in suture anastomoses, with reendothelialization beginning earlier (within 7 days after anastomosis as compared with 2 to 4 weeks). The tissue tensile strength at 1 hour was less in laser anastomoses than in suture anastomoses, but the laser anastomoses still withstood an intraluminal pressure load of 380 mm Hg. Laser anastomosis improved the microscopic and histologic appearance of the intimal layer, allowing for rapid early reendothelialization and resulting in excellent patency rates.     

Long-term effects of extraluminal dilatation with a rigid circle on arteriovenous anastomotic line in venous grafts transposed into arterial defects

Postanastomotic narrowing resulting from subintimal hyperplasia is a well-known phenomenon. In the current study the authors compared a metallic circle and conventional suture technique in anastomoses performed in two ends of external jugular vein grafts interposed in carotid arteries of rabbits. They recorded the patency rates, fluid flow rates, and histological effects of the circle on the anastomotic line and compared them with conventional suture anastomoses. In 16 rabbits (experimental group) a standard suture was used in both ends of the jugular vein graft transposed to the carotid arteries on one side. On the other side, circle anastomoses were performed on both ends of the vein graft. In an additional 8 rabbits (control group), the anterior jugular veins and carotid arteries were dissected on both sides and left. During postoperative week 12, in 8 rabbits of the experimental group, the flow rates of carotid arteries were measured in vitro, and intraluminal silicone casts were prepared. In the remaining 8 experimental rabbits, carotid angiographies were performed and anastomotic segments were harvested for histological examination. Flow rates were also measured in the control group, and artery and vein segments were harvested. The patency rates of the vein grafts with metallic circle anastomoses were 100%, whereas conventional suture patency was 75% at week 12. Flow rates were significantly higher in the metallic circle-anastomosed vein grafts (74 ml per minute vs. 123 ml per minute, mean values; p < 0.05). Histological examination revealed reduced intimal thickness in the metallic circle anastomoses compared with conventional suture anastomoses. Dilatation of the arteriovenous end-to-end anastomotic line by a rigid circle prevents anastomotic narrowing in the long term.     

Patency of laser-assisted anastomoses in small vessels: one-year follow-up

Laser-assisted arterial anastomoses can now be performed with satisfactory short-term patency. This study was undertaken to evaluate patency and aneurysm formation with a 1-year follow-up. A microscopically guided CO2 laser was used to anastomose 1.5 to 2.0 mm carotid arteries in 24 rabbits. Under X6 to X40 magnification, 60 to 70 mW were delivered with a spot size of approximately 0.32 mm. One carotid artery underwent laser anastomosis; the opposite served as a sutured control (10-0 nylon sutures). The 48 end-to-end anastomoses were evaluated for patency and aneurysm formation at 3, 6, and 12 months. Aneurysms were defined as a 1.5 times increase in diameter at the anastomotic site. The vessels underwent microscopic examination. All laser-assisted and sutured anastomoses were patent up to 1 year. At 3 months, one of eight sutured and one of eight laser anastomoses were aneurysmal; stenosis was noted in one laser anastomosis. At 6 months, one of eight laser and 0 of eight sutured anastomoses were aneurysmal. At 12 months, one of eight rabbits had died; of the remaining seven, three of seven laser and zero of seven sutured anastomoses were aneurysmal. In total, five of 23 (21.7%) aneurysms developed with the laser technique and one of 23 (4.3%) with the suture technique (p less than 0.05). Laser-assisted anastomoses are technically feasible, and patency at 1 year is equal to those performed with the suture technique. Aneurysm formation is a consistent problem that demands further investigation.     

Laser-assisted end-to-end BioWeld anastomosis in an ovine model

The BioWeld tube, an albumin-based exovascular stent, has been used for microsurgical anastomoses and compared to conventional sutures. The study presented investigated the potential of the BioWeld tube for vascular anastomosis in larger vessels. Laser-assisted BioWeld anastomoses were compared to conventional-sutured anatomoses of the carotid artery of Merino-x ewes. The BioWeld procedure resulted in 100% survival and 100% patency at 1 and 6 week post-operative periods, with no noticeable foreign body response. Sutured animals showed 100% survival and patency. The ischemic time for BioWeld anastomosis averaged 15 minutes compared with 10 minutes for sutures. This study indicates that the BioWeld tube is an easy to use anastomotic technique with equivalent success rates and comparable anastomotic times.     

Arterial reconstruction with vascular clips is safe and quicker than sutured repair.

BACKGROUND: Non-penetrating, arcuate-legged vascular-closure staple clips made of titanium were initially developed for microvascular anastomoses with little experience of their use in larger vessels. The purpose of this study was to compare vascular-closure staple clips to sutured anastomoses in common iliac arteries in a porcine model. METHODS: In an experimental study, transected iliac arteries on both sides of 11 pigs were randomly assigned to end-to-end anastomosis performed with vascular-closure staple clips or interrupted 6-0 polypropylene sutures. Angiographic, macroscopic and microscopic results were assessed after 2 months. RESULTS: There was no significant difference in the patency rate, tensile strength of the anastomoses, vessel diameter at the repair site, intimal thickness or wall thickness of the arteries after either method of closure. The mean (s.d.) clamp time was 19.8 (6.1) minutes for clip repair, and 36.0 (6.9) seconds for suture repair (P < 0.001). The times required for the reconstruction of the anastomoses were 17.4 (6.1) and 35.5 (7.1) minutes, respectively (P < 0.001). CONCLUSIONS: Arterial anastomoses performed with vascular-closure staple clips are faster than sutured anastomoses, and result in comparable wound healing when assessed for patency, tensile strength, degree of narrowing and intimal reaction.     

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.     

Classification and comparison of five techniques of end-to-end microarterial anastomoses in rats: A new proposed technique

We propose a new classification of five main techniques for microarterial anastomoses: interrupted, autogenous cuff, continuous, sleeve and partial sleeve. The last method was developed by the authors. A study was performed on 48 albino rats and comprised 20 anastomoses of each type (for a total of 100), performed on femoral and carotid arteries of average size 0.83 mm. These were compared with respect to patency, anastomosis time, leak, bleeding time, number of sutures (bites), microangiography, histopathology and scanning electron microscopy. The overall patency was 88%, and that of the partial sleeve technique was 100%, associated with 30% incidence of aneurysms. Clinical, histopathological and scanning electron microscopy findings showed better results for techniques with predominantly extraluminal sutures (sleeve and partial sleeve), which was particularly relevant in our situation, in which a larger sized needle (150 μm) had to be used. An overall aneurysm incidence of 17% was noted. © 1995 Wiley-Liss, Inc.     

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.     

Is the GraftConnector a valid alternative to running suture in end-to-side coronary arteries anastomoses?

BACKGROUND: An animal study was carried out to compare long-term patency rates of coronary anastomoses performed with the GraftConnector versus running suture technique. METHODS: 10 sheep, 45 to 55 kg, underwent off-pump coronary artery bypass grafting (right internal mammary artery to left anterior descending artery). In 5 animals, the anastomosis was performed with a GraftConnector and in 5 animals with 7-0 running suture. Intraoperative fluoroscopy and a fluoroscopic control at 6 months were performed. After 6 months, the animals were sacrificed and the anastomoses were examined histologically. RESULTS: All animals survived at 6 months with 100% anastomosis patency rates in both groups. In the GraftConnector group, the anastomosis diameter at 6 months fluoroscopy was 118% of native left anterior descending artery versus 97% of the control group. Luminal anastomotic width at histology was 1.7 +/- 0.2 mm in the device group versus 1.6 +/- 0.1 mm in the control group. Mean intimal hyperplasia thickness was 0.21 +/- 0.1 mm in the device group versus 0.01 mm in the control group. CONCLUSIONS: The GraftConnector provides a consistent and reproducible coronary artery anastomosis and reduces technical demand and manual dexterity in coronary operations. Long-term results demonstrate that off-pump coronary artery bypass grafting performed with the GraftConnector had the same patency rate and luminal width as those performed with running suture.     

A comparison of CO2 laser-assisted venous anastomoses and conventional suture techniques: patency, aneurysm formation, and histologic differences

The expected patency and the potential complications of CO2 laser-welded end-to-end venous anastomoses have not been well established despite increasing clinical interest in the subject. To further study this relatively new technique we used the internal jugular veins (1.0 to 1.4 mm diameter) of 15 New Zealand White rabbits weighing 2.5 to 3.5 kg. On one randomly selected side, a laser-welded end-to-end anastomosis was performed in all animals by placing three equidistant stay sutures followed by welding the vein edges with a CO2 laser (spot size of 0.27 mm, power of 100 mW, and power density of 175 W/cm2). On the contralateral side, the vein was anastomosed with interrupted 10-0 nylon sutures in 10 animals, and in the remaining five animals a continuous 10-0 nylon suture technique was used. All anastomoses were surgically assessed at 30 days after operation. A significantly lower 30-day patency rate (p less than 0.05, Fisher's Exact Test) was found in anastomoses constructed by use of the continuous technique (20%) compared with either interrupted (90%) or the laser-assisted technique (87%). No significant difference was observed in 30-day patency between laser-assisted and conventional interrupted anastomoses. Anastomoses performed with the continuous and the laser-assisted technique required 12.5 +/- 1.3 and 12.9 +/- 3.0 minutes, respectively, whereas those constructed with interrupted technique required 19.1 +/- 4.5 minutes (p less than 0.05, Student-Neuman-Keuls' Test). No evidence of false or true aneurysm was noted in any of the animals. Histologic evaluation of laser-assisted anastomoses demonstrated early full-thickness coagulation necrosis of the wall with reendothelialization by 7 days and complete healing by 30 days after the procedure. Conventional anastomoses showed reendothelialization and minimal necrosis near the sutures at 7 days, but healing was complete by 30 days after the procedure. The patency rate of vein anastomoses performed with the CO2 laser is excellent and superior to the one obtained with continuous sutures, and except for less operating time, the former technique does not appear to offer any significant advantage over the conventional interrupted suture technique for small vein anastomosis in this animal model up to 1 month of follow-up.     

Laser-Fused Biologic Vascular Graft Anastomoses

Tissue fusion using laser energy is a promising new technology that may improve the healing of anastomoses. This study evaluated the feasibility of using argon laser energy to fuse vascular tissue and biologic vascular prostheses (St. Jude Medical, Inc.) in a canine arteriovenous (A-V) fistula model. Five animals had 4-cm length, 3-mm internal diameter grafts (n;eq 10) placed bilaterally as side-to-side A-V interpositions from the femoral artery to femoral vein. One A-V graft was placed using argon laser energy with the vessel edges aligned by 6-0 polypropylene traction sutures at 3 to 4 mm intervals. The contralateral graft was sutured using running 6-0 polypropylene suture. Anastomoses were successfully fashioned in all animals except for episodes of delayed bleeding at two laser-fused segments (15 min and 2 hrs) and one segment in a suture control (6 days). The implants were removed to evaluate the integrity and healing of the anastomoses at 2 hrs, 8 days, and at 7, 9, and 11 weeks. In all instances, there was no evidence of anastomotic dehissance or enlargement. Histologic examination of the anastomoses revealed coapted vessel and prosthetic edges in laser-fused specimens and a limited foreign-body response to the permanent sutures in the suture controls. In the longer term specimens there was marked intimal proliferation at the venous anastomosis in all implants, with recent bilateral occlusions of the 7 and 11 week implants at the venous connection. We conclude that laser fusion of biologic vascular prostheses to autogenous vessel is possible with healing and no evidence of anastomotic dehissance. The technique may provide a method to limit development of anastomotic stenosis by eliminating the foreign body reaction. In addition, the canine arteriovenous model used in these experiments develops aggressive intimal lesions at the venous anastomosis within weeks and may be used to evaluate the effect of anastomotic technique on the development of this lesion.     

A new combined "interrupted-continuous" microvascular anastomotic technique. Experimental study and clinical application

A new combined interrupted-continuous microvascular anastomotic technique is introduced, using four interrupted stay stitches and continuous suturing in between. Its efficacy is compared with the simple interrupted and continuous techniques. Microanastomoses were performed in the femoral artery and vein of rats. The patency, anastomosis time, and blood loss from the suture line of all anastomoses were recorded. Also, the sites of all anastomoses were harvested and histologically examined for lumen stenosis, media regeneration, and endothelial lining. Experimentation findings showed 100% patency rate in all groups. The combined and the continuous techniques were significantly faster and watertight compared with the simple interrupted. The only difference in pathology findings was the development of significant lumen stenosis in vein anastomoses performed with the continuous technique, compared with the other two techniques. The combined technique was clinically used in 16 free flap transfers and ensured 100% patency in all arterial and vein anastomoses, as well as survival of all flaps. In conclusion, the combined technique was found to be fast and easy to perform and ensured the same patency rate as the simple interrupted and continuous techniques. It also diminished the lumen stenosis effect of the continuous technique in vein anastomoses. Therefore, we suggest its use in both experimental studies and clinical cases.     

Anastomosis of bypass grafts using a low-powered CO2 laser

The purpose of this study was to evaluate the feasibility of using a low-powered CO2 laser to perform end-to-side anastomoses of bypass grafts. The internal jugular veins of 13 domestic swine were removed and used as grafts to bypass their ligated carotid arteries. Each end of the vein graft was apposed to the artery with four to six temporary stay sutures, and a waveguide delivery CO2 laser with a power density of 900 mW/mm2 was used to perform the anastomoses, after which the sutures were removed. The animals were sacrificed postoperatively at five time intervals: 2 to 4 hours, 5 days, 1 month, 3 months, and 5 months. Of the 10 anastomoses studied at 2 to 4 hours, 70% were fully patent, none thrombosed, and 30% disrupted. Of the 16 anastomoses studied between 5 days and 5 months postoperatively, 88% were patent, 12% thrombosed, and none disrupted. None of the animals developed aneurysms at any stage of this investigation. Histologic analysis of acute studies revealed thermal damage such as charring of tissue, unraveling of the collagen fibrils, and the formation of microvacuoles. Within 3 months, the anastomotic sites showed localized healing with intimal fibromuscular proliferation and dense fibrous tissue. Good apposition of tissue was found to be of great importance in achieving patency of vessels in this procedure.     

Comparison of absorbable and nonabsorbable sutures for microsurgical vasovasostomy in rats

Objectives. At least 12% of initially patent vasovasostomies (VVs) shut down. Currently, only nonabsorbable sutures are used for VV. A synthetic, slowly absorbing, monofilament polyglactin suture has been developed that retains tensile strength for up to 6 months. We performed a prospective controlled randomized study comparing absorbable and nonabsorbable sutures for rat VVs.Methods. Bilateral microsurgical VV was performed in three groups of 36 Wistar male rats, with 10-0 nylon, 10-0 polypropylene, and 10-0 polyglactin sutures. Twelve control rats underwent sham operations. Three rats in each group were killed at 2, 6, 12, and 24 weeks. The abdominal end of the vas deferens was transected and the intraluminal fluid examined microscopically for presence of sperm. The segment of the vas deferens containing the anastomosis was excised. Fluid from the testicular end was examined for sperm to confirm spermatogenesis. Patency was confirmed by an antegrade indigo carmine vasogram of the anastomotic segment. Segments were randomly sent for histologic or tensile strength evaluation.Results. The mean tensile strength of the anastomoses performed with nylon was slightly higher than in polypropylene and polyglactin sutures, although the difference was not statistically significant. Polyglactin consistently maintained tensile strength throughout 6 months without significant fluctuations. The mean patency rate in the polyglactin group was 96%, in nylon 81%, and in polypropylene 61%. Although polyglactin had a consistently higher patency rate compared with nonabsorbable sutures, the difference was not statistically significant (P = 0.11) but indicated a strong trend. The occurrence of microscopic sperm granuloma, muscle layer injuries, intimal fibrosis, and adventitial fibrosis of the vas deferens was not significantly different between suture types.Conclusions. The three suture materials appear equivalent with respect to overall tensile strength of anastomosis; with histologic evaluation, the trend was toward better patency with polyglactin. Polyglactin 10-0 microsurgical suture is a viable alternative to nonabsorbable sutures in microsurgical VVs, although further studies are indicated to assess long-term results.     

Mechanics of end-to-end artery-to-PTFE graft anastomoses

On some occasions vascular surgeons are called upon to construct an end-to-end anastomosis using prosthetic graft material. If a spatulated anastomosis is not fashioned, three important variables that are under the surgeon’s control could affect anastomotic dimensions: (1) selection of graft material, (2) graft size relative to the native vessel, and (3) suture technique. Accordingly, studies were performed on 36 nonspatulated, end-to-end artery-to-polytetrafluoroethylene (PTFE) grafts to evaluate the effects of graft size and suture technique on anastomotic dimensions. Size-matched (3 mm) and slightly oversized (4 mm) grafts were anastomosed end-to-end to 3 mm pig carotid arteries using (1) running polypropylene (Surgilene) sutures, (2) running polybutester (Novafil) sutures, or (3) interrupted sutures. After 30 min the vessels were excised, filled with contrast material, and radiographs were obtained to measure anastomotic dimensions. Results showed that, at every comparable pressure, 4 mm grafts produced larger anastomoses than did 3 mm grafts. In addition 4 mm grafts produced smoother anastomoses without a constricted or “pinched” appearance at the graft-artery junction. Marked compliance mismatch was observed with both sized grafts. There was no significant difference in the dimensions of the anastomoses or compliance mismatch with the three different suture techniques. These studies indicate that, when using PTFE grafts for end-to-end anastomoses, a graft that is slightly larger than the artery is preferable to provide the largest and smoothest anastomosis, and that any of the three suture techniques may be used. PTFE grafts were provided by W. L. Gore, Flagstaff, AZ. Sutures were provided by Davis & Geck, Co., Danbury, CT. No other support, direct or indirect, was provided by any manufacturer.     

Nd: YAG laser–welded canine arteriovenous anastomoses

This preliminary report describes formation of femoral arterio-venous fistulas (n = 10) in six dogs using a 1.32-μm wavelength Nd:YAG laser welding technique. Stay sutures (6-0 polypropylene) were placed at 5–7 mm intervals along the anastomoses for vessel apposition. Delivery of laser energy through a 400-μm diameter fiber optic was controlled by a new computer-based software system. At 3 mm distance above the anastomosis, energy fluences of 110–260 J/mm²/cm length of anastomosis were used for laser welding. One or two additional hemostatic sutures were required in seven of the ten anastomoses. Flow was maintained for 1–2 hours prior to tissue harvesting. No thrombosis or delayed anastomotic failures were observed after initial welding and repair. Histologic examination revealed good apposition and adherence between wall layers and a fibrinous coagulum at the intimal junctions. Mild thermal injury of the wall was present at some anastomoses. This early investigation suggests that a 1.32 μm Nd:YAG laser welding technique can successfully create large vessel arteriovenous fistulas in the canine. © 1994 Wiley-Liss, Inc.