Superiority of end-to-end versus telescoped bronchial anastomosis in single lung transplantation for pulmonary emphysema

OBJECTIVE: To assess the influence of surgical technique (telescoped versus end-to-end anastomosis) on the incidence of bronchial anastomotic complications in patients who underwent single lung transplantation for pulmonary emphysema. METHODS: Seventy-six adult recipients of single lung transplants for pulmonary emphysema were evaluated for the presence of 3 types of major bronchial anastomotic complications: ischemia, dehiscence, and severe stenosis. Surgical technique, clinical course, and mortality were reviewed retrospectively. RESULTS: The 3 major complications were observed in 11 (34%; ischemia), 8 (25%; dehiscence), and 11 (34%; severe stenosis) of 32 telescoped bronchial anastomoses. In contrast, ischemia, dehiscence, and severe stenosis occurred in only 4 (9%), 1 (2%), and 2 (5%) of 44 end-to-end anastomoses (P =.0087, P =.0034, and P =.0012, respectively). The relative risk of ischemia, dehiscence, and severe stenosis in telescoped anastomoses was 2.1, 2.5, and 2.5, respectively, compared with end-to-end anastomoses. Five (13%) telescoped anastomoses required stent placement as compared with only 2 (5%) end-to-end anastomoses (P =.1244). Early postoperative pneumonia was more common in the telescoped anastomosis group (56%) than in the end-to-end group (32%; P =.0380). There was a trend toward shorter survival in the telescoped anastomosis group (mean survival 1045 +/- 145 days) as compared with the end-to-end group (mean survival 1289 +/- 156 days), but these differences did not achieve statistical significance (P =.2410). CONCLUSIONS: In patients who underwent single lung transplantation for pulmonary emphysema, telescoped anastomoses were associated with a higher incidence of bronchial anastomotic complications than end-to-end anastomoses.     

Effect of heparinized irrigating solutions on patency of experimental microvascular anastomoses

The effect of five different irrigating solutions on patency of four different types of microvascular anastomoses was studied. The solutions used were lactated Ringer's without heparin and four lactated Ringer's solutions with varying concentrations of heparin ranging from 10,000 units/liter to 100,000 units/liter. These were tested on four different anastomotic models in the rat: 1) end-to-end femoral arterial anastomosis; 2) end-to-side arterial bypass graft; 3) end-to-end venous anastomosis; and 4) end-to-side venous bypass graft. There were statistically significant differences in patency rates among the solutions only in the end-to-end venous anastomosis group. In these, significantly higher patency was achieved with heparinized lactated Ringer's solution at 20,000 units/liter. The use of higher concentrations of heparin in these solutions resulted in decreasing patency rates and appears to be contraindicated.     

Histopathology of microarterial anastomoses: end-to-end versus end-in-end (sleeve) technique

The healing process of microarterial anastomoses after two different techniques is described after an evaluation of 80 rabbit arterial anastomoses. The two techniques used were as follows: group I, conventional end-to-end technique; and group II, end-in-end (sleeve) technique. After operation the anastomoses were checked at 1 hour, 24 hours, 3 days, 7 days, 2 weeks, 6 weeks, 3 months, and 6 months. The changes occurring at the tunica intima, tunica media, and adventitia were histologically evaluated and morphometric measurements were taken at the anastomotic site. Histologic evaluation of both techniques showed that the rabbits treated with the sleeve technique healed faster with less endothelial damage. The sleeve technique presented a different healing pattern but comparable long-term patency rates with the conventional end-to-end anastomosis technique.     

Clinical experience with non-penetrating vascular clips in free-flap reconstructions.

To date, the gold standard for performing a microvascular anastomosis has been the penetrating suture with attached needle. During the last two decades, non-penetrating techniques have been introduced, including the Unilink system for end-to-end anastomoses, and the VCS clip-applier system for both end-to-end and end-to-side anastomoses. The aim of this study was to compare the results of different techniques used to create microvascular anastomoses in free-flap reconstructions. Between January 1995 and October 1999, we performed 474 microvascular anastomoses in 216 consecutive free-tissue transfers. The anastomosis techniques included manual sutures (42%), Unilink rings (34%) and VCS clips (24%). Seven combined sutured-clipped anastomoses were excluded from further analysis. The mean anastomotic time when rings were applied was significantly shorter than when using clips (P 0.0001) or sutures (P 0.0001). Venous anastomoses using clips took less time than those using sutures (P 0.05). There were 19 anastomotic failures, all of which lead to early flap failure. Ten flaps were salvaged by early reoperation; nine flaps were lost. Three more flaps were lost as a result of other causes, bringing the flap survival rate down to 94.4%. Early flap failure was caused by failure of the arterial anastomosis in eight cases; all of them were sutured (these represented 5% of all arterial anastomoses with sutures). None of the clipped arterial anastomoses failed. Early flap failure was caused by failure of the venous anastomosis in 11 patients. Three of these anastomoses were sutured (representing 6% of all venous anastomoses with sutures), seven were anastomosed with rings (representing 5% of all venous anastomoses with rings) and one was clipped (representing 2% of all venous anastomoses with clips). Both the VCS clip-applier system and the Unilink system are easy to handle and allow fast microvascular anastomoses without intraluminal penetration. The patency rate of clipped vessels is at least as good as the patency rates of vessels anastomosed using sutures or rings.     

Effects of a venous cuff at the venous anastomosis of polytetrafluoroethylene grafts for hemodialysis vascular access

INTRODUCTION AND METHODS: The most frequent complication of polytetrafluoroethylene (PTFE) arteriovenous grafts for hemodialysis is thrombotic occlusion due to stenosis caused by intimal hyperplasia. This complication is also known for peripheral bypass grafts. Because the use of a venous cuff at the distal anastomosis improves the patency of peripheral bypass grafts, we considered that it might also improve the patency of PTFE arteriovenous grafts. Therefore, a randomized multicenter trial was carried out to study the effect of a venous cuff at the venous anastomosis of PTFE arteriovenous grafts on the development of stenoses and the patency rates. RESULTS: Of the 120 included patients, 59 were randomized for a venous cuff. The incidence of thrombotic occlusion was lower in the cuff group (0.68 per patient-year) than in the no-cuff group (0. 88 per patient-year; P =.0007). However, the primary and secondary patency rates were comparable. The cuff group tended to have fewer stenoses at the venous and arterial anastomoses when examined with duplex scan. Graft failure was higher in patients with an initial anastomosing vein diameter smaller than 4 mm (7 of 18 [39%]) than in those with a vein diameter of 4 mm or larger (16 of 88 [18%]; P =. 052). Local edema, skin atrophy, and obesity yielded a higher risk on graft failure (23% vs 11%). CONCLUSION: A venous cuff at the venous anastomosis of PTFE arteriovenous grafts for hemodialysis reduced the incidence of thrombotic occlusions; stenosis at the venous anastomosis was reduced. However, this did not result in a better patency rate. Therefore, the venous cuff should not be used routinely. Initial vein diameter and local problems (edema, obesity, or skin atrophy) appear to be the most important risk factors for graft failure.     

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.     

Endothelialization of anastomoses in the aorta and inferior vena cava of the rat

Denuding endothelial damage at anastomoses may lead to thrombotic complications and failure of microvascular reconstructions. Confluent endothelial healing at anastomoses may reduce thrombotic and other complications. The progress of endothelial coverage of anastomotic structures in the aorta and inferior vena cava (IVC) of the rat was evaluated at 3,5,8,11, and 14 days after completion of the anastomoses, by means of scanning electron microscopy. Arterial anastomotic patency was 100%; venous patency was 84%. It was found that endothelial healing progressed towards thin confluent coverage first, thereafter thickening. Coverage was first achieved at the needle defect, then the anastomotic junction, and lastly the suture. The same stage of endothelial coverage of anastomotic structures was reached 5 to 8 days sooner at the IVC anastomosis than in the aorta. © 1994 Wiley-Liss, Inc.     

End-to-end versus end-to-side arterial anastomosis patency in microvascular surgery

The patency rates of microsurgical end-to-end and end-to-side anastomosis in the rat carotid artery were studied. Seventy end-to-end and seventy end-to-side arterial anastomoses, using 10-0 nylon interrupted sutures, were performed on 140 Sprague-Dawley rats. Findings indicated 100% patency in end-to-end as well as end-to-side immediately and 1 week post-anastomosis. This investigation suggests that there is no significant advantage between the methods studied based on vessel patency alone. The decision to perform an end-to-end vs. an end-to-side arterial anastomosis should be based upon the clinical circumstances encountered, since no significant difference in patency rates exists. © 1998 Wiley-Liss, Inc. MICROSURGERY 18:125-128 1998     

Influence of topical heparin on stasis-induced thrombosis of microvascular anastomoses.

An experiment was done to determine whether topical heparin and the association of anastomoses with dependent tissue (free flaps) exert any influences on stasis-induced microvascular thrombosis. Rat femoral vessel anastomoses with or without free flap construction were used in a total of 50 male Sprague-Dawley rats. Saline either with or without heparin was used for intralumenal irrigation during the anastomosis. Following anastomotic repair, the femoral vessels were reclamped, inducing stasis for either 2 or 4 hr. Our results showed that static blood had little adverse effect on thrombosis at the arterial anastomosis when reclamped for up to 4 hr in both standard and flap-associated anastomoses. Topical heparin significantly reduced the incidence of stasis-induced thrombosis of venous anastomoses. The venous patency rates in standard anastomoses were lower than those in flap-associated anastomoses after both 2 and 4 hr of stasis. From these results, we conclude the following. 1) Arteries may be reclamped for up to 4 hr without detriment despite static blood being in contact with the anastomotic site. 2) Topical heparin may be helpful in increasing the patency rate of venous anastomoses after a period of blood stasis. 3) Free flap construction may play a role in decreasing stasis-induced microvascular thrombosis.     

Comparison of tensile strength and thrombus formation between mechanical microvascular anastomoses using a biodegradable ring device and sutured anastomoses

The purpose of this study was to evaluate whether early motion following mechanical anastomosis using a biodegradable ring device was possible or not, by measuring tensile strength and the rates of thrombus formation at anastomotic sites. Bilateral femoral arteries and veins of 24 rabbits were repaired by sutured anastomoses and biodegradable ring anastomoses. The tensile strength of the anastomotic site was measured by constant loading with a material-testing machine, using specimens excised at 24 hr, 72 hr, 1 week, and 2 weeks after anastomosis. The tensile strength of biodegradable ring arterial anastomoses was significantly stronger than sutured anastomoses at 24 hr, 72 hr, 1 week, and 2 weeks. No statistically significant differences were observed in venous anastomoses at any interval. In separate experiments, biodegradable ring anastomoses and sutured anastomoses of the bilateral femoral arteries of 18 rabbits were constructed, and early passive knee motion was carried out at 100 times once a day with maximum spreading of the hip joint for 24 hr, 72 hr, and 1 week. Thrombus formation at the anastomotic sites was evaluated by scanning electron microscope (SEM). SEM showed no thrombus formation in the biodegradable ring anastomoses at any interval; however, thrombi were observed in the sutured anastomoses (33 to approximately 50 percent).     

Modified anastomotic technique for 1 millimeter internal diameter polytetrafluoroethylene arterial grafts in the rat.

Reported patency rates after standard end-to-end anastomoses for microvascular prosthetic grafts have been inconsistent and usually disappointing. A modified anastomotic technique is described in which the prosthetic graft is invaginated inside the arterial lumen. In this study of 6 cm lengths of 1 mm internal diameter polytetrafluoroethylene femoro-femoral bypass grafts in the rat, 6 (40%) of 15 grafts with standard anastomoses were patent at 6 months compared to 28 (90%) of 31 grafts using the modified anastomotic technique (P < 0.001). With invagination of the prosthetic graft inside the arterial lumen, reliable high patency rates can be achieved with microvascular prostheses long enough for potential clinical applications.     

Management of significant venous discrepancy with microvascular venous coupler

Microsurgery has revolutionized the art of reconstruction, with the discovery of the ability to replace like tissue with like tissue transferred from a distant site. The evolution of the tissue transferred has also progressed. No longer are free flaps based off a dominant anatomically named vessel, but one of its later derivatives, the perforator. Perforator breast reconstruction dominates the authors' practice, and a frequently encountered problem is mismatched vessels. This situation typically requires more time and concentration for successful completion. Venous mismatches tend to be harder to overcome than arterial; the venous hand-sewn end-to-end anastomoses result in bunching of the larger vessel around the perimeter of the smaller. In this low flow system, these anastomotic imperfections can frequently result in anastomotic failure. Many other techniques have also been described in hopes of improving the anastomotic success. These are often timely or lack improvement in patency rates. The authors have found the MCA microvascular venous coupler to be a reliable method to overcome this problem. The end-to-end technique of microvascular coupling allows a perfect intima-to-intima anastomosis despite the variation in caliber of the vessels. The time to complete the end-to-end anastomoses is significantly reduced to only a matter of minutes.     

Continuous suture technique in microvascular end-to-end anastomosis

A refined technique for continuous suturing of end-to-end anastomoses is presented along with a study in which the continuous-suture technique was compared with the standard interrupted-suture technique in end-to-end anastomoses in the femoral arteries of 20 rats. The results of this comparative study demonstrate that the two techniques had equal patency rates, but that the continuous-suture technique required less than 50% of the time necessary to perform end-to-end anastomosis with interrupted sutures.     

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.     

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.     

The morphology and patency of arterial and venous microvascular anastomoses throughout the first post-operative year. A histological study

End-to-end microvascular suture anastomoses, 40 arterial and 41 venous, from the rabbits carotid artery and posterior facial vein were harvested at 5 different time intervals (1, 2, 3, 6 and 12 months) post surgery and evaluated with light microscopy. A 100% long-term patency was noted both in arteries and veins. Quantitative measurements of the width of the vessel wall components indicated that a statistically significant temporary hypertrophic response occurred in the arterial intima, culminating in the third month when the width of the vessel wall at the anastomotic level almost doubled the normal. After that the width of the vessel wall again declined but it remained thicker than the adjacent vessel wall at one year post surgery. Among the venous anastomoses, however, the wall thickness at the anastomotic level remained thinner than the adjacent vessel wall throughout the evaluation period. The original vessel wall characteristics are not restored at the anastomotic site with intimal hyperplasia compensating for medial necrosis. Despite these events a technically satisfactory microvascular anastomosis should remain patent for years.     

Orthotopic intestinal transplantation using the cuff method in rats: a histopathological evaluation of the anastomosis.

Segmental small intestine transplantation (SIT) in rats, using a cuff technique, has achieved a high success rate. However, there have been few reports on the influence of the foreign body reaction to polyethylene cuff on vessel anastomoses and graft after SIT. This study involves the histopathological examination of the site of cuff anastomosis and grafts in the short- and long-term survival of segmental SIT. The data obtained from the suture anastomosis model also served as a control. One week after heterotopic segmental SIT using the cuff technique, orthotopic continuations were carried out in syngeneic combination. Twenty-five of 30 rats surviving >200 days (83.3%) were examined for vessel anastomosis. All arterial anastomoses were patent, but the portovenous anastomoses in 10 grafts (33%) were totally occluded and were associated with the formation of collateral vessels. Histopathological examination demonstrated good patency of the artery and vein anastomotic site in the short term, but granulation, fibrosis, and neovascularization at the anastomosis site surrounding the cuffs in the long-surviving group. However, the grafts appeared to be intact, with normal features of the villi. On the contrary, the site of the sutured anastomosis in the long-survival rats showed no inflammatory reaction. Although a polyethylene cuff caused foreign body reaction, the graft blood supplies were maintained by collateral vessels. Considering the low mortality and high success rate, polyethylene cuff is good for short-term study and an alternative method for long-term SIT experiments.     

Microvenous thrombosis rates following anastomosis with vein grafting and a knotted suture

An experimental microvenous thrombosis model was developed combining vein grafting in femoral vein defects with exaggerated vessel injuries using a knotted suture in the vessel repair. The rat femoral vein grafts were separately subjected to injuries caused by an anastomosis performed with a suture knotted with eight half-hitches at the distal anastomosis (upstream), the proximal anastomosis (downstream), and both anastomotic sites. These groups were compared to vein grafting done with a standard suture. Vessel patency was assessed at 20 min and 24 hr, and the thrombus component was histologically analyzed at 24 hr after the procedures. One hundred percent of control vein grafts were patent at 24 hr. All experimental groups had significantly decreased patency at 24 hr (P<0.001). Among the experimental groups, knotted suture anastomoses at both anastomoses produced significantly lower patency (13.3%, P<0.05) than knotted suture anastomoses at distal anastomoses. Histological analyses of thrombosed grafts showed that a large amount of thrombocyte deposition and inflammatory cells were noted at both anastomotic sites in the vein grafts with a knotted suture at the distal anastomosis and in the grafts with a knotted suture at both anastomoses. Thrombocyte deposition and inflammatory cells were seen only at the site of proximal anastomosis when using a knotted suture at the proximal anastomosis site alone. This study demonstrated that quantified microvenous thrombosis can be produced by exaggerating vessel injuries with a knotted suture in a vein graft model. This thrombosis model can be used to study the effects of antithrombogenic agents. © 1995 Wiley-Liss, Inc.     

Carotid artery end-to-end anastomosis in the rat using the argon laser

Microvascular end-to-end anastomoses of rat common carotid arteries measuring 0.6 to 0.7 mm in diameter were performed using an argon surgical laser system. Vascular bonding with the argon laser was accomplished in all cases. The anastomosed carotid artery segments were evaluated both angiographically and histologically at 1 day, 1 week, and 1 month after laser bonding. With increasing time after anastomosis, there was a trend toward increasing angiographically proven stenosis of the anastomotic segment and histologically demonstrated pseudoaneurysm formation of the vessel wall at the bonded site. Pseudoaneurysm formation was associated with a dense inflammatory response in the anastomotic vessel segment. In spite of excellent initial tissue bonding and vessel patency, the delayed results of progressive vessel wall disruption and segmental stenosis indicate that further experience in using the argon laser for vessel welding is needed before this method can be accepted as an alternative to current microvascular suture technique.     

Exploration of the intravascular stenting method for sub 1-mm vessels

The intravascular stenting (IVaS) method was published by Narushima and Koshima in 2008. This method involves using a monofilament nylon stent to make the anastomosis of small vessels easier. The aim of this study was to explore the IVaS technique to determine its advantages, disadvantages, and usefulness for inexperienced microsurgeons and also for more experienced practitioners during difficult anastomoses. The study was approved by the Catholic University of Louvain Animal Experimentation Ethics Committee. The study was done on 20 Wistar rats; each rat acting as his own control. Group 1 had an anastomosis done with the IVaS technique on the femoral artery. Group 2 had a classic end-to-end anastomosis without a stent. All anastomoses were performed by the same trainee surgeon with 4 months experience in microsurgery. The diameter of the external artery, distance between the double clamp forceps, stent length, number of sutures, stent preparation, and installation time and suture time were all measured. Anastomotic patency was verified using O'Brien's Patency test. The rats were anesthetized 1 week later to reassess the patency of the vessels. While the anastomotic time was shorter in the stent group, the preparation time was longer and so the total time to perform the anastomosis in both groups was the same. All vessels were patent at the completion of the anastomosis. At 1 week, patency rates were identical (83.3%) in both groups. The study shows an improvement in suturing time in the IVaS group. The time saved is equivalent to the time required for preparation and installation of the stent. At 7 days, the Patency test was identical for the two groups (83.3%). IVaS technique is a useful method of vessels anastomosis especially for junior surgeons. The reason why the patency rate was not 100% at 1 week may be because of excessive manipulation of the stent causing thrombosis in the IVaS group and imperfections in suturing technique by a trainee surgeon. Different aspects of the method are open for discussion such as consideration of the stent size and execution of the anastomosis. The IVaS technique helps in the execution of anastomosis in microsurgery and allows for more precise suturing. Care, however, must be taken in its execution and manipulation so as to avoid any lesions of the intima of the vessels.