Vein graft anastomoses with magnets.

BACKGROUND: Performing vascular anastomoses requires complete circumferential access and is time-consuming and technically challenging. The purpose of our study was to assess a sutureless magnetic device for anastomosing vein grafts. METHODS AND RESULTS: Oval magnets with a lumen were placed in six male foxhounds. The femoral artery was ligated and an 8 cm length of femoral vein was harvested and reversed. After a 4 mm venotomy or arteriotomy, one magnet was inserted into each vessel lumen and a second magnet was placed outside the vessel but aligned directly over the intraluminal magnet, forming a magnetic port in each vessel. The graft and target vessels were then allowed to self-align and seal, creating a side-to-side anastomosis. Patency was confirmed with duplex Doppler ultrasound scans after 6 and 13 weeks and during explantation after 14 weeks. At that time, the contralateral femoral vein was harvested and an acute graft was created as a control. Macroscopically there was no sign of stenoses or aneurysms. After explant, saline was perfused through all grafts and the hydrodynamic resistance was quantified. There was no significant difference in resistance between the acute and 14-week grafts indicating stenosis. Microscopic examination of 14-week anastomoses showed that all blood-contacting surfaces were well-endothelialised. CONCLUSIONS: The magnetic vascular coupler allowed sutureless anastomoses between blood arteries and veins. This device might prove useful for anastomosis of large and small vessels, as well as for anastomosis or approximation of non-vascular structures such as peripheral nerves, fallopian tubes or ureters.     

Automated distal coronary bypass with a novel magnetic coupler (MVP system)

OBJECTIVE: We sought to assess the feasibility of performing sutureless distal coronary artery bypass anastomoses with a novel magnetic coupling device. METHODS: From May 2000 to April 2001, single-vessel side-to-side coronary artery bypass grafting on a beating heart was performed in 39 domestic white pigs (35-60 kg) without the use of mechanical stabilization, shunts, or perfusion bridges. Animals were divided into 2 groups. Seventeen pigs underwent right internal thoracic artery to right coronary artery bypass grafting through a median sternotomy (group 1) with a novel magnetic vascular positioning system (MVP system; Ventrica, Inc, Fremont, Calif). Twenty-two pigs underwent left internal thoracic artery to left anterior descending artery grafting with the MVP anastomotic device through a left anterior minithoracotomy (group 2). This system consists of 2 pairs of elliptical magnetic implants and a deployment device. One pair of magnets forms the anastomotic docking port within the graft; the other pair forms an identical anastomotic docking port within the target vessel. The anastomosis is created when the 2 docking ports magnetically couple. Anastomotic patency was evaluated by means of angiography during the first postoperative week and at 1 month. Histologic studies were performed at different time points as late as 6 months. RESULTS: Right internal thoracic artery to right coronary artery anastomoses and left internal thoracic artery to left anterior descending artery anastomoses were successfully performed with the system in all animals. The self-adherent and self-aligning properties of the implants allowed for immediate and secure approximation of the arteries (total anastomotic time between 2-3 minutes). Anastomoses were constructed without a stabilization platform. Five nondevice-related deaths occurred postoperatively. One-week angiography, performed in 35 surviving animals, showed a patent graft and anastomosis in all cases. The patency rate at 1 month was 97% (33/34). Histologic studies as late as 6 months demonstrated neointimal coverage of the magnets without any significant luminal obstruction. Histology also confirmed the presence of viable tissue between magnets. CONCLUSION: The MVP anastomotic system uses magnetic force to create rapid and secure distal coronary artery anastomoses, which might facilitate minimally invasive and totally endoscopic coronary artery bypass surgery.     

Argon laser-assisted anastomoses in medium-size vessels: one-year follow-up

Laser-assisted anastomosis of medium-size vessels can be performed with satisfactory short-term patency. This study was undertaken to evaluate patency and structural integrity up to 1 year. An argon laser was used to make bilateral femoral arteriovenous anastomoses in 12 dogs compared to conventional suture method in another 8 dogs. These anastomoses were evaluated for patency and aneurysm formation at 1 hour; 1, 2, 4, and 8 weeks; and 12 months after surgery. All anastomotic sites were patent and without aneurysmal change or luminal narrowing at all harvesting intervals. Histologic examination revealed that within 1 month laser anastomotic sites were almost completely healed and without intimal hyperplasia. In suture anastomoses, foreign-body reaction remained evident up to 1 year. Use of the argon laser for medium size vessel anastomoses resulted in excellent patency without aneurysm formation or intimal hyperplasia even in the long term. These data suggest promising clinical applications.     

Remote distal arteriovenous fistula to improve infrapopliteal bypass patency

The results of the use of prosthetic materials for femorocrural bypass surgery have been less than optimal. The creation of a distal anastomotic arteriovenous fistula to augment blood flow and velocity through the graft is well known. However, it may create turbulence at the anastomosis and steal blood flow away from the distal artery. A canine model was developed to evaluate the effect of fistula size on graft/arterial hemodynamics. In 16 patients we have constructed a distal arteriovenous fistula, which is remote from the distal anastomosis, and we studied the effect of such fistulas on bypass patency and distal arterial hemodynamics. Patients selected for this procedure had multiple previously failed reconstructions and limb-threatening ischemia and did not have usable autogenous vein. Femorotibial bypass graft reconstructions were performed with polytetrafluoroethylene followed by the creation of a side-to-side arteriovenous fistula 5 to 15 cm below the distal anastomosis in the same artery and accompanying veins. We have achieved a 1-year patency of 67% with a 75% limb salvage rate. We also serially measured blood flow and velocity within the bypass, the arteriovenous fistula, and the distal outflow vessel using duplex scanning after surgery. Mean estimated blood flow through the bypass during the immediate postoperative period was 264 ml/min, the arteriovenous fistula was 157 ml/min, and the distal artery was 19 ml/min. Unlike an arteriovenous fistula created at the distal anastomosis, a remote distal arteriovenous fistula not only increases graft blood flow but also augments native arterial blood flow between the distal anastomosis and fistula and thus may improve distal limb perfusion.     

A new method of vascular anastomosis by CO2 laser: experimental and clinical study

It is difficult to maintain the long-term patency after conventional anastomosis especially for the small caliber vessels. Since 15 years we have performed aortocoronary bypass with suture materials for the patients with ischemic heart disease. There are some problems in maintaining the long-term patency of the bypass grafts. Low energy CO2 laser was utilized to make vascular anastomosis with a few stay sutures. Vascular anastomoses (side-to-side, end-to-end, end-to-side) were carefully made by CO2 laser in the regions of the femoral arteries and veins, the carotid arteries and jugular veins in dog. A-C bypass was also successfully carried out between the internal mammary artery and the left anterior descending artery under the beating heart in experiment. Outputs of 20-40 mW and irradiation times of 6-12 sec/mm were optimal conditions for anastomosis of the small caliber vessels. There were no problems in the intensity and the healing of the anastomotic sites in comparison with the conventional suture method. On the basis of these excellent experimental results a low energy CO2 laser was employed clinically for vascular anastomosis of the peripheral vessels in 28 patients with angina pectoris or chronic renal failure and cardiac failure. There were no complications such as bleeding and suture line aneurysm after surgery. In conclusion, vascular anastomosis by laser might be recommended in performing with safety and rapidity for small caliber vessels.     

Arterial end-to-side anastomosis with the UNILINK system

A new technique for mechanical end-to-side anastomoses using the UNILINK anastomotic system is presented. The technique, based on the concept of vessel wall eversion over paired ring pins, is described as is a new device for vessel expansion. To evaluate the technique of end-to-side anastomosis, we detached the left renal artery in 18 rabbits and then reanastomosed them end-to-side to the aorta using the UNILINK anastomotic system. Renal blood flow was evaluated before and after anastomoses with a laser Doppler flowmeter. Animals were separated into three groups of 6 and were killed at 24 hours, 2 weeks, and 16 weeks, respectively. To evaluate the acute effects of vessel expansion, 7 additional rabbits underwent expansion of the aorta without subsequent anastomosis. All vessels were evaluated with light and scanning electron microscopy. A patency rate of 100% was achieved in the 18 animals; histological changes at the anastomotic site were comparable to those described previously for this mechanical anastomotic system. The animal model demonstrates that it is both technically possible and efficacious to perform end-to-side anastomoses of arteries with the UNILINK anastomotic system.     

One year results of sequential mammary artery anastomoses. 120 clinical cases. Angiographies: 71 patients]

From 1985 to november 1989, 270 patients underwent sequential anastomosis with left internal mammary artery (LIMA) on left descending artery (LDA) and diagnonal artery (DA). The first 120 cases have 100% one year follow-up. The perioperative status was: angina stage III or IV: 59%; myocardial infarction (MI): 45%, stenosis of 3 vessels: 52.5%; stenosis of main coronary artery: 10.8%. 2.25 anastomoses were performed per patient. Side-to-side anastomosis (kissing) were not diamond anastomoses but axial and longitudinal. The use of fibrin gllude provides regular curves of the graft between anastomosis. Mortality was 0.8%, morbidity was: MI: 4.2% (2 small infarcts in anterior vessels, 3 others in non-grafted vessels); mediastinitis: 1%; severe bleeding (reoperation): 1%. At one year 93% of patients are free from angina and 71 patients underwent angiographic assessment (145 LIMA anastomosis). Results are as follow: side-to-side anastomosis patency: 98.5%; distal anastomosis obliteration: 3%; LDA anastomosis patency: 95.7% overall sequential anastomosis patency: 97.6%. These results have led our cardiologist in Brest to naturally prefer a surgical approach than percutaneous angioplasty when LDA and DA are involved.     

A new technique for anastomosing veins to small-caliber arteries

A new technique of arteriovenous anastomosis is presented which lessens the complication of intravascular turbulence and thrombosis seen with elongated and narrow anastomotic segments. The axillary artery and jugular vein were anastomosed in 10 ZBZ-Cara rats using microsurgical techniques. The jugular vein was prepared as a tubular structure facilitating two end-to-end anastomoses rather than the customary end-to-side technique. Angiographic patency was demonstrated at 3 weeks in 10/10 rats. Two of ten anastomotic segments were considered quite narrow; however, angiographic demonstration of flow was excellent.     

Double-donor, single-lumen, end-to-side anastomosis

One of the major problems in extracranial-intracranial bypass procedure is the inadequate caliber of the superficial temporal artery branches. In this study, a new end-to-side anastomosis technique that permits two small caliber arteries to be used as a single donor vessel is presented. The external and internal branches of the right common carotid artery were modified to provide a single lumen, and an end-to-side anastomosis was performed between these vessels and the contralateral common carotid artery in 10 rats. One week after the operation, angiography was performed and the patency of anastomoses was demonstrated in 9 of 10 rats.     

Magnamosis: magnetic compression anastomosis with comparison to suture and staple techniques

Purpose

An ideal anastomosis between hollow viscera should be easily performed, strong, and operator independent. We hypothesized that transluminal attraction between magnets in the intestine could be harnessed to create an intestinal compression anastomosis (magnamosis) with these characteristics. We further hypothesized that variation of attraction force and geometry of compression would affect the quality of the intestinal anastomosis.

Methods

We designed a self-orienting device composed of 2 neodymium-iron-boron magnets affixed to polytetrafluoroethylene moldings. Two topologies were evaluated: one designed with ‘uniform’ compression and the other with ‘gradient’ compression. Sixteen young adult pigs (Sus scrofa) underwent laparotomy with creation of a magnetic side-to-side anastomosis: 8 with the uniform device and 8 with the gradient device. Each also had a stapled anastomosis, and 5 had an additional hand-sutured anastomosis. Animals were euthanized at 1, 2, and 3 weeks after operation, then anastomoses were compared on the basis of gross appearance, histology, functional radiography, and mechanical integrity.

Results

All magnetic devices formed patent anastomoses without leak. One stapled anastomosis resulted in a contained leak. Mechanical integrity of magnetic anastomoses was not statistically significantly different from staple or suture counterparts, and there was a trend toward greater strength with magnetic anastomoses. Comparison between device types revealed the gradient device trended toward greater strength and earlier patency (67% vs 33% at 1 week). There was no evidence of stenosis, and histologic examination demonstrated tissue remodeling with mucosal and serosal apposition across the magnamoses.

Conclusions

The magnetic compression anastomosis (magnamosis) device is a safe and effective means of sutureless full-thickness intestinal anastomosis with serosal apposition in a pig model. Gradient compression is superior to uniform compression. This technique is compatible with endoscopic and natural orifice approaches.     

Butylcyanoacrylate adhesives in microvascular surgery: an experimental pilot study

An investigation was undertaken to examine the effects of the butylcyanoacrylate adhesives (Histoacryl) on vascular tissue. Using a rat femoral artery model, 18 vessels were prepared. End-to-end anastomoses were completed using three stay sutures of 10-0 nylon inserted at 120 degrees intervals around the vessels, followed by direct application of Histoacryl glue. Results showed a patency rate of 73 percent, the vessels being inspected between two and 14 weeks after anastomosis. Histological examination of the vessels showed an early marked foreign body granulomatous response with giant cell formation, and later extreme thinning of the vessel wall, splitting of the elastic lamina, and calcification of the media. It was concluded that the histologic results of butylcyanoacrylate tissue adhesives on the vessel wall preclude their use on human subjects.     

Technique to re-establish continuity of the recipient artery after end-to-end anastomoses in cross-leg free flap procedure

In this report, a simple technique is described to restore the continuity of the recipient artery in cross-leg free flap procedure after end-to-end anastomoses. In the first stage, the latissimus dorsi flap was revascularized by end-to-end anastomosis between the posterior tibial artery of the noninjured leg and the thoracodorsal artery of the flap. After 4 weeks of neovascularization period, in the second stage when the pedicle was to be divided, the thoracodorsal artery was dissected until its bifurcation in the muscle, transected, and rerouted to the distal ligated end of the posterior tibial artery, accomplishing a simple end-to-end anastomosis between these two vessel ends. Thus, the continuity of the recipient artery was re-accomplished by replacing the normally discarded segment of the flap's arterial pedicle as an arterial graft, the patency of which was demonstrated clinically and by Doppler examination. The authors believe that this technique provides further benefit to the patient by accomplishing vascular flow through a major lower limb artery when the reconstructive pathway involves an end-to-end anastomosis in a cross-leg free flap procedure.     

A new probe for the anastomosis of small vessels.

We developed new probes with three varying sizes (phi1.0, 1.5 and 2.0 mm) with a trench for guiding the needle which made small vessel anastomoses easy and suture placement accurate with clear identification of the vessel lumen. We evaluated the efficiency of these probes on anastomoses using the bilateral common carotid arteries of cadaver rabbits. The anastomosis time of end-to-side anastomosis was shortened by using the probe from 20.2+/-3.3 to 15.4+/-2.6 min, and of side-to-side anastomosis from 20.2+/-1.3 to 16.0+/-1.2 min. Of the 5 end-to-side anastomoses without the probe, there was one deformity of the anastomoses site and of the 5 side-to-side anastomoses without the probe, there was one stenosis of the anastomosis. There were neither deformity nor stenosis of the 10 anastomoses of 5 end-to-side and 5 side-to-side anastomoses with the probes. In conclusion, the probe with a trench for guiding the needle made small vessel anastomoses easy.     

Optimal patency rates obtained in coronary artery grafting with circular vein grafts.

Twenty-two patients underwent coronary artery grafting with a circular vein graft comprising four or five distal coronary anastomoses. Postoperative angiographic evaluation showed patency in 90 (95.7 percent) of the 94 coronary anastomoses fashioned in this manner. All four occlusions occurred in the one patient whose graft comprised five anastomoses and was occluded beyond the first anastomosis on the right coronary artery (RCA). Eleven of the 94 anastomoses were made onto arteries with limited runoff. Blod flow averaged 214 ml. per minute (range 130 to 320) in the main portion of the graft and 59 ml. per minute (range 35 to 100) in the most distal segment. Flow doubled (averaged 403 ml. per minute) in the 11 grafts injected with papaverine. The technique of circular vein grafting is described in detail and potential pitfalls are outlined. The reasons for the high early patency rate are believed to be the following: (1) high flow in the proximal segment of the graft insuring patency of said segment, (2) termination on the left anterior descending (LAD) coronary artery providing good distal flow and patency. (3) diamond-shaped side-to-side anastomoses (SSA's) preventing angulation of the graft at these crucial points, and (4) nearly equidistant anchoring at the site of the multiple anastomoses giving the graft a smooth, even contour.     

Complete arterial coronary revascularisation using radial artery conduit for double thoracic artery inlet flow: arterial sling operation.

BACKGROUND: Coronary artery bypass graft surgery with arterial revascularisation of all diseased coronary vessels is considered highly efficient because arterial grafts have an excellent long-term patency compared with venous grafts. However, problems to reach the infero-lateral wall with the in situ internal thoracic arteries usually require alternative techniques. We present the first results of a new surgical principle using a free radial artery segment to complete the arterial coronary revascularisation and concomitantly connect the internal thoracic arteries. METHODS: In patients referred for coronary bypass surgery and three-vessel disease an end-to-end anastomosis of the right internal thoracic artery and the radial artery segment preceded cardiopulmonary bypass, during which side-to-side anastomoses of the radial artery segment were used to revascularise stenotic branches of the right coronary and circumflex arteries. The left internal thoracic artery was used for revascularisation of stenotic branches of the left anterior descending artery, and finally an end-to-side anastomosis of the radial artery segment to the left internal thoracic artery was performed. Coronary artery blood flow was measured in 41 patients with Doppler flow probe. RESULTS: One hundred and ninety-two coronary anastomoses (an average of 4.2 per patient) were performed in 46 patients. We measured a mean total blood flow in the arterial sling graft of 104ml/min (range 35-221ml/min), compared with 69 and 68ml/min of the single inlet right and left internal thoracic arteries, respectively (P<0.01). Flow capacities of 104 and 120ml/min of the right and left internal thoracic arteries were measured during clamp of both the aorta and the contralateral internal thoracic artery. The mean crossclamp duration was 77min (range 51-113min). Postoperative angiography demonstrated patent graft anastomoses to all coronary arteries. There were no perioperative deaths or myocardial infarctions. One patient had a minor postoperative stroke. DISCUSSION: Complete arterial revascularisation can be achieved by the arterial sling operation with an acceptable crossclamp time and a high early rate of graft patency. The double arterial inlet provides a 50% higher blood flow to the beating heart and two-fold increase in the flow reserve compared with a single inlet. Although further research including long-term follow-up of this new principle is required, the present findings seem promising and suggest that the arterial sling operation has a potential role for complete arterial coronary revascularisation.     

Evaluation of an absorbable ring for vascular anastomosis.

An absorbable ring for vascular anastomosis was developed, composed of a copolymer of L-lactic acid and glycolic acid (7:3 mole percent). It has an external diameter of 3.0 mm, a thickness of 1.0 mm, and an inner diameter of 1.0 mm, with six stainless steel pins and six opposed holes. With this ring, femoral artery anastomoses were performed in 27 rabbits. One, 2, 6, and 30 weeks after anastomosis, the femoral artery was harvested and patency was evaluated by light and scanning electron microscopy. Absorption of the ring occurred within 30 weeks. Of the 27 animals, the anastomosed vessel was patent in 24 cases, for a patency rate of about 89 percent. Vascular anastomosis with the absorbable ring is useful, and the device may compensate for some of the drawbacks of manual suturing and the conventional non-absorbable ring.     

Increasing vessel diameter with the open Y technique for diameter discrepancy

Free tissue transfers have increasingly become the mainstay of plastic surgery for the last two decades. Size discrepancy between the vessels in microsurgery is frequently encountered in clinical practice and may potentially be an important factor in the patency of the anastomosis. A rat model has been devised to improve the diameter discrepancy in microvascular anastomosis. Twenty Wistar rats have been used for this purpose. The external jugular vein was cut 1 mm distally from the bifurcation of the anterior and posterior facial veins. Both legs of the resultant Y-shaped vessel were united after inserting microscissors from one leg and exiting from the other. Performing an end-to-end anastomosis between the vein, which acquired an increased diameter as a result of this procedure, and the carotid artery prepared in the neck, helped to create an arteriovenous shunt. Patency was assessed in the operated rats 2 weeks later. In order to achieve a better understanding of the advantages of this technique, another study was carried out. In this subsequent study, specimens were collected from fresh sheep cadavers, including the brachiocephalic trunk, right common carotid, and right subclavian arteries. Different specimens were compared from each of the vessels and also from each of the subclavian and carotid arteries after they were joined together with the open Y technique and increased diameters of the vessels are obtained. As a result, the authors demonstrated that size discrepancy between the vessels was decreased, patency with a percentage of 94.1 was obtained, and when specimens from the fresh cadavers were evaluated, a reasonable gain was achieved. (p < 0.0001).     

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.     

Treatment of vertebral artery aneurysms with posterior inferior cerebellar artery-posterior inferior cerebellar artery anastomosis combined with parent artery occlusion

BACKGROUND: In patients with aneurysms that involve the origin of the posterior inferior cerebellar artery (PICA) and require occlusion of the vertebral artery (VA), revascularization of the PICA is commonly performed. We present six patients with dissecting VA aneurysms who underwent PICA-PICA anastomosis combined with parent artery occlusion. METHODS: After a lower lateral suboccipital craniectomy and partial resection of the jugular tubercle, anastomoses were performed in a side-to-side fashion at the posterior medullary segment of the PICA. The VA was subsequently occluded by clipping proximal and distal to the aneurysm, and the PICA was occluded by clipping distal to the aneurysm. RESULTS: Postoperative cerebral angiography demonstrated patency of the anastomosis and regression of the aneurysm in five of six patients. The remaining patient experienced hemorrhage from contralateral VA dissection and subsequently died. One patient experienced myopathy of the lower extremities secondary to intraoperative fixed board compression and developed permanent lower extremity muscular weakness. The remaining four cases experienced no new neurologic deficits. CONCLUSION: PICA-PICA anastomosis is a useful procedure for reconstruction of the PICA when parent vessel occlusion or trapping is necessary to exclude a VA aneurysm involving the origin of the PICA.     

Utility and limitation of sequential saphenous vein graft for complete revascularization in coronary artery surgery

Multiple bypass grafting in complete myocardial revascularization requires frequently the use of sequential saphenous vein grafts as well as arterial grafts. To expect the favorable good clinical results of revascularization, therefore, refined surgical technique for saphenous vein grafting and proper selection of suitable coronary arteries for bypass are important. Between January 1989 and April 1990, 91 patients underwent CABG utilizing internal thoracic arteries (ITA) in 79% and SVG in 99% of the patients with an average of 3.3 anastomoses per patients. Postoperative angiography was performed 4 or 8 weeks after surgery. Early patency rates were 92% (204/221) in overall anastomotic sites, 96% (52/54) in ITA and 91% (152/167) in SVG respectively. There was no difference in patency rates between individual (90%) and sequential (92%) grafts. In sequential grafting, however, patency rate of side-to-side anastomosis was higher than that of end-to-side anastomosis. Patency rates of the grafts were also evaluated in terms of the sizes of coronary arteries and intraoperative graft flows. These studies lead to the following conclusions: In individual grafting, the acceptable patency rate can be expected when the graft flow exceeds 30 ml/min even if the internal diameter of coronary artery is less than 1.5 mm. In sequential grafting, on the other hand, a diameter more than 1.5 mm is desirable for the coronary artery at the site of end-to-side anastomosis.