Study on microvascular anastomosis of arteries with absorbable polyglyconate suture

A synthetic, monofilament, slowly absorbing suture material, polyglyconate suture was tested to determine its suitability for use in microarterial anastomoses under ordinary tension and under undue tension. Microvascular repair of 34 rat femoral arteries averaging 0.63 mm in diameter using 8–0 polyglyconate suture on an atraumatic needle gave an immediate patency rate of 100% and a late patency rate of 94.1% after 1 to 24 weeks. Microanastomoses of 30 rabbit femoral arteries averaging 1.43 mm in diameter using 8–0 polyglyconate suture on an atraumatic needle gave an immediate patency rate of 100% and a late patency rate of 96.7% when a vessel segment of 3 to 7 mm was resected. Morphological studies included light microscopy and scanning electron microscopy. The results showed that polyglyconate suture retains tensile strength for an adequate period to allow vascular healing and causes a less pronounced tissue response than nonabsorbable nylon suture. Complete absorption of the suture material was followed by a complete regeneration of the vessel wall. These results demonstrated that absorbable polyglyconate suture might be suitable for microvascular anastomosis of arteries under ordinary tension and under tension to a certain degree. © 1995 Wiley-Liss, Inc.     

微小血管端端连续吻合与间断吻合的比较研究

目的 评价 0．7－2mm的血管用连续端端吻合法的价值。方法 对45只成年免及30只成年鼠,随机分成外径为0．8mm（x^-,下同）、1．5mm、1．9mm的动脉组和外径为2．1mm、1．1mm的静脉组,共5组。每组动物一侧用端端连续吻合,中一侧用间断吻合。术后1、2、4周,各组选5只实验动物,行勒血试验、血管造影和组织学检查。结果 与血管间断吻合相比,血管连续吻合的时间能降低47％－22％（P＜0．01）。血管吻合的通畅率、血栓形成、以及血管内膜的修复,两者差异无显著性意义（P＞0．05）。结论 与间断吻合技术相比,连续端端合外径为0．7mm-2.2mm的血管,能明显节省吻合时间。     

Comparison of continuous and interrupted suture techniques in microvascular anastomosis.

We evaluated the efficacy of the continuous suture technique (CST) in arteries and veins with varying external diameters (ED). In study 1 a direct end-to-end anastomosis was performed in 5 groups of animals (n = 15 in each group): group 1, rabbit carotid artery (ED, 1.8-2.0 mm); group 2, rabbit femoral artery (ED, 1.4-1.6 mm); group 3, rat femoral artery (ED, 0.7-0.9 mm); group 4, rabbit femoral vein (ED, 2.0-2.2 mm); and group 5, rat femoral vein (ED, 1.0-1.2 mm). In study 2 a graft from the femoral vein was interposed into the carotid artery, with a ratio of the diameter of graft to artery of 1.3:1 in the rats (group 6, n = 12) and 1:1 in the rabbits (group 7, n = 12). In each animal the vessel on one side was repaired using CST and the opposite vessel using the interrupted suture technique. Vessel samples were harvested 1, 2, and 4 weeks after anastomosis. The CST significantly reduced anastomosis time by up to 47% in arteries and 41% in veins. Bleeding time and blood loss were also significantly reduced with CST. Similar results were found in study 2. The total thrombosis rate was 8%, but no significant patency difference was noted between the CST and the interrupted suture technique in any vessel category. We conclude that the CST is a reliable and time-saving procedure in microvascular anastomosis of arteries with diameters greater than 0.7 mm and of veins with diameters greater than 1.0 mm.     

Does the nicotine patch help in the postoperative period for arterial vessel repair?

This study attempts to determine whether a nicotine patch will affect the patency rate of the femoral artery anastomosis in a smoking rat model. Twenty-four rats underwent a smoking protocol of 4 weeks of exposure to cigarette smoke in a smoking chamber at 1 hour per day, using a 1:10 dilution of unfiltered cigarette smoke. Each rat then underwent a femoral artery transaction and anastomosis. Postoperatively, the rats were divided into two groups of 12. Group I had no postoperative smoking or nicotine therapy. Group II had nicotine patch treatment only. The femoral artery was evaluated for flow 7-days postoperatively. At the time of anastomosis, the femoral arteries were smaller in diameter, averaging 0.5 mm (0.4-0.7 mm) as opposed to the normal 0.75-1 mm. All anastomoses were patent at 5 min when the wound was closed. No difference in patency rate occurred with the use of the nicotine patch.     

The ring technique for end-to-side microvascular anastomosis

The ring technique for end-to-side microvascular anastomosis employs a resorbable polyglycolic acid ring to prevent stenosis and spasm at the anastomotic site. In 20 rats, the ring technique was compared with the conventional technique for constructing end-to-side anastomoses between the femoral (0.9-1.1 mm) and superficial epigastric (0.3-0.4 mm) arteries. The ring technique proved superior to the conventional end-to-side technique both in speed of execution and in patency at 3-4 weeks (100% vs 70%). Grossly and microscopically, the ring was completely resorbed at 3 wk.     

Arterial anastomosis using the telescoping method and an elastomeric adhesive

We experimentally studied a new technique for anastomosis of small arteries which involves the telescoping method and a surgical adhesive with the objective of examining its clinical potential. This technique was applied to the unilateral femoral arteries of 27 mongrel dogs. After division of the artery, the distal artery was incised longitudinally, and the proximal end was invaginated into the opened artery. One stay suture and the elastomeric adhesive PUP201 were placed in the anastomotic site. The bursting and tensile strength and the patency were examined, and a histopathological study was performed at various intervals up to 1 year after the operation. The bursting strength exceeded 500 mm Hg. The patency rate of the anastomosed arteries was 100%. The mean percentage of stenosis to diameter of the proximal normal lumen was 20% one year after operation. The luminal surface of the anastomosed line was healed smoothly, and thrombi between the telescoped arteries were replaced by elastofibrotic union. In conclusion, small arterial anastomosis using the telescoping method and an elastomeric adhesive is easy and safe and provides good patency.     

Effect of inflow and outflow sites on the results of tibioperoneal vein grafts

We have reviewed our experience with the tibial vessel bypass operation and have found the overall patency and limb salvage rates to be acceptable. Patients were divided into two groups based on the site of the proximal anastomosis. In Group I, the proximal anastomosis was at the common femoral artery and in Group II, the proximal anastomosis was at the distal superficial femoral artery or the popliteal artery. The patients in the two groups were similar with regard to indications for operation, age, and sex. However, in Group I, 35 percent of the patients were diabetic and in Group II, 74 percent of the patients were diabetic. In the Group I patients, the 72 month graft patency rate was 65 percent with a limb salvage rate of 75 percent. In the Group II patients, the 72 month patency rate was 81 percent with a limb salvage rate of 89 percent. Some possible explanations for this slightly better result in Group II patients are discussed. All tibial bypasses were divided into three groups based on the recipient tibial artery. Analysis revealed that the 72 month patency rates were as follows: the anterior tibial artery 63 percent, the posterior tibial artery 81 percent, and the peroneal artery 80 percent. These differences were not significant but indicate, as others have recently pointed out, that the peroneal artery is indeed an acceptable recipient artery for tibial bypass surgery.     

Experimental study of hollow, absorbable polyglycolic acid tube as stent for vasovasostomy

Bilateral vasovasostomy in 16 rats permitted evaluation of a microsurgical technique using an original absorbable hollow stent made of polyglycolic acid. Advantages of this stent included ease of anastomosis, maintenance of luminal patency, satisfactory approximation of vasal ends, and reduction of perivasal inflammation possibly due to reduction of extravasation of sperm. Absorbable stents were eliminated within four weeks of placement, and patency was confirmed by histologic studies performed two, four, and six weeks after vasovasostomy.     

The effects of suturing technique and vessel size on patency after microarterial repair.

According to most of the literature, sutures for microarterial repair must include the intima to prevent an "intimal flap" and occlusion of the anastomosis. Some authors have said that vessel diameter affects patency rate. This study was designed to evaluate these two statements. The femoral arteries (about 1.0 mm in diameter), the epigastric arteries (about 0.5 mm), and the central ear arteries (about 0.5 mm) of rabbits were studied. Alternate arteries were repaired using conventional suturing techniques or sutures which included the adventitia and media but excluded the intima. The patency rate in the 1 mm or 0.5 mm vessels was not affected by inclusion or exclusion of the intima from the microarterial repair. The patency rate for conventionally repaired arteries 1 mm in diameter was significantly higher than that for 0.5 mm arteries.     

The use of long synthetic microvascular grafts to vascularise free flaps in rabbits

A 5 cm length of 2 mm internal diameter (i.d.) synthetic, expanded polytetrafluoroethylene (PTFE, or Gore-Tex) vascular graft was used to connect 25 rabbit inferior epigastric flaps to the contralateral femoral vessels. In 15 animals an expanded PTFE graft connected the opposite femoral artery to the flap while the ipsilateral venous drainage remained intact. In the remaining 10 animals an expanded PTFE graft was used to replace the venous drainage of the flap and connected to the opposite femoral vein while the ipsilateral femoral artery supplied the flap. Flap survival and graft patency were evaluated over 3 weeks. Ten of 15 flaps with intra-arterial grafts survived at 3 weeks (67%). Only 27% (4/15) of their supplying grafts remained patent for 3 weeks, although 67% (10/15) were patent at 10 days. All 10 flaps, where expanded PTFE grafts replaced venous outflow, failed within 36 hours. At exploration these grafts were thrombosed or collapsed. In conclusion, currently available 2 mm (i.d.) expanded PTFE vascular graft cannot maintain patency in a low blood flow circulation supplying an isolated free flap.     

Assessment of the microsurgical skills: 30 minutes versus 2 weeks patency

The aim of this study is to evaluate the amount of training needed by a trainee, with no background in microsurgery, in order to achieve proper skills for microvascular anastomosis. A protocol based on the rat femoral artery was established to provide a quantitative representation. Five inexperienced subjects started performing microvascular anastomosis. Patency was assessed at 30 min. The final assessment was performed at 2 weeks when rats were reoperated and the patency below the anastomosis was checked. The experiment was discontinued for one subject when he/she succeeded to have two series of four anastomosis with 100% patency at 2 weeks. The results were: 47.5% patency rate at 30 min and 7.5% at 2 weeks (series 1-2); 67.5 and 32.5% (3-4); 82.5 and 35% (5-6); 100 and 70% (7-8); 100 and 87.5% (9-10). Two trainees obtained 100% patency at 2 weeks after series 9-10. Other three needed two more series. There is a significant statistic difference (P < 0.01) between the results at 30 min and 2 weeks for the series (1-2, 3-4, 5-6, 7-8). The patency rate at 2 weeks reflects in a better way the microsurgical skills of a trainee. For long term functioning anastomosis, the training period needs an extension beyond that necessary for 100% patency at 30 min.     

New microvenous anastomosis model for microsurgical training: external jugular vein

In microsurgical training, the femoral vein is used frequently for a microvenous anastomosis model. But the femoral vein in the rat does not completely simulate the human vein because of its thin wall, fragility, and tendency to collapse. These anatomic characteristics cause some difficulty in carrying out anastomoses in microsurgery training particularly for beginners. The authors propose the external jugular vein of the rat for microsurgical training in microvenous anastomoses. In 10 Wistar rats, the anatomy of the external jugular vein was studied by dissection and histology. Anatomic dissections demonstrate that the external jugular vein has an average diameter of 1.9 mm (range: 1.6 to 2.1 mm) without tendency to collapse. The vein is easily dissected without any accompanying anatomic structure for an average segment of 45 mm, allowing effortless approximator clamp placement. Comparison of its cross section with that of the femoral vein and other previously described models by light microscopy and scanning electron microscopy reveals a larger diameter and much thicker vessel wall with a prominent tunica media and adventitia. Based on the anatomic findings in 20 rats, the external jugular vein was anastomosed with end-to-end standard microsurgical technique using 8-0 (n = 10) and 10-0 (n = 10) nylon sutures. Results indicate a 100 percent patency rate immediately after the anastomosis for the two subgroups and 100 percent and 90 percent patency rates 1 week after the procedure for the 10-0 and 8-0 nylon suture groups, respectively. This model presents some advantages: the vein is easily dissected with the naked eye without using the operating microscope because it is the largest vein among the superficially located veins in the rat, and has a thick vessel wall without tendency to collapse. The operative area allows for training inbilateral microsurgical anastomoses using a single skin incision and is safe from autocannibalization. The model simulates clinical microvenous anastomosis better because of its similarities to human large diameter flap veins.     

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.     

An absorbable pinned-ring device for microvascular anastomosis of vein grafts: experimental studies

In the rabbit, posterior facial vein segments were grafted to the femoral arteries using either conventional suture technique or a mechanical absorbable pinned-ring device. The purpose of this study was to compare patency rates and anastomotic times for the two different methods. The anastomoses were evaluated macroscopically and using light and scanning electron microscopy. The grafts anastomosed with the absorbable rings exhibited 100% patency, while only 83% of the sutured grafts were patent. The mean anastomotic time using the mechanical pinned-ring device was 18.1 min (range 9.8-30 min). The conventionally sutured anastomoses were completed in a mean time of 60 min (range 50-75 min). The experiment has confirmed that the absorbable pinned-ring device provides a safe and fast way to perform microvascular anastomosis.     

Eversion endarterectomy of the superficial femoral artery and end-to-side anastomosis to the deep femoral artery: An alternative to extended profundoplasty

The success of aortofemoral reconstruction in patients with superficial femoral artery occlusion depends on the restoration of a satisfactory pulsatile flow to the deep femoral artery. In 18 patients with multilevel disease, widespread involvement of the deep femoral artery, and poor distal outflow, we performed an eversion endarterectomy of the proximal segment of the superficial femoral artery and constructed an end-to-side anastomosis between this segment and the distal deep femoral artery. In 10 patients, the reconstruction was performed after thrombectomy of the occluded aortofemoral graft, and in 8 the two reconstructions were simultaneous. The actuarial patency rate was 93.5 percent at 1 year and 75.2 percent at 5 years. Four late femorodistal bypasses were performed that gave an actuarial limb salvage rate of 68.8 percent at 1 year and 61.6 percent at 5 years. In selected cases, this technique is a valid alternative to an extended profundoplasty or to a femorodistal bypass.     

Perioperative dilation for vessel-size discrepancy using a percutaneous transluminal angioplasty catheter

The problem of vessel-size discrepancy is still unsolved in microvascular-free tissue transfers. In an effort to develop a technique perioperatively to dilate smaller vessel diameters, the authors utilized a catheter customarily used in coronary angioplasties, the percutaneous transluminal coronary angioplasty (PTCA) catheter. Twenty New Zealand rabbits were divided into two groups: Group 1 consisted of 14 experimental animals; Group 2 of six control animals. In both groups, a segmental defect of 2 cm was created in the proximal portion of the femoral artery just below the inguinal ligament, where the vessel diameter is 2.0+/-0.1 mm. In Group 1 animals, an arterial graft was harvested from the superficial femoral artery in the contralateral lower extremity, where the vessel diameter is 1.0+/-0.1 mm. The arterial graft along its entire length was dilated, using a PTCA catheter up to 2 mm in diameter. The duration of dilation was 3 min with pressure applied at 2.5 atm. Before and following dilation, sections were obtained from both ends of the graft for histologic comparison. The grafts were then interposed within the defect and microvascular anastomoses were performed. In the control group, an arterial graft of the same length as in the experimental group was harvested from the contralateral upper femoral region, where the vessel diameter is 2.0+/-0.1 mm. These grafts were then interposed within the defect and microsurgically anastomosed. Seven days later, the patency of the anastomoses was evaluated in both groups. In 13 of 14 rabbits in the experimental group, the anastomoses were patent and the arterial grafts maintained their dilated diameters (2 mm). In all six control animals, the anastomoses were patent. A statistical comparison of vessel patency using Fischer's exact chi-square test showed no significant differences between the experimental and control groups (p = 0.7). Histologically, the dilated arteries demonstrated intact endothelial layers.     

Micro-arterial anastomosis using only two sutures and an autogenous cuff

Microvascular anastomosis using only two sutures and an autogenous cuff was carried out in an experimental model of Wistar albino rats. 40 femoral and 40 epigastric arteries were used for this cuff technique and compared with conventional technique in the same number of vessels. The cuff technique is simple, quick, causes less trauma to the vessel wall and gives a good patency rate. Anastomosis of an artery 0.5mm in diameter is very easy with the cuff technique (98% patency) which remains difficult using conventional technique (0% patency). The disadvantage of this technique may be leakage of blood just after releasing the clamps due to restoration of blood flow, but this is easily controlled within few minutes by mild compression.     

Dialysis fistulae patency and preoperative diameter ultrasound measurements.

BACKGROUND: This study was designed to investigate the possibility of defining a vascular diameter with a practical cut-off point, which predicts a successful patency for radiocephalic arteriovenous fistulae in dialysis patients. METHODS: This is a retrospective analysis of prospectively gathered data. Consecutive patients (n=148) with chronic renal failure, needing vascular access for haemodialysis, were included if they underwent duplex ultrasound examination to evaluate preoperatively the vascular status and diameters for radiocephalic arteriovenous fistulae (RCAVF) construction. The associations between the diameter of the radial artery and cephalic vein and primary failure at six weeks, primary and secondary patency at one year were investigated. RESULTS: There was no significant association between either radial artery diameter or dilated cephalic vein diameter and primary failure. There was an association between radial artery diameter and primary patency (Overall P=0.042). Males had a significantly larger mean radial artery diameter than females (P=0.005). Gender did not influence primary patency. CONCLUSION: We recommend using radial artery diameters of > or = 2.1 mm and < or = 2.5 mm for RCAVF construction, this diameter category having the highest patency at 1 year. A single cut-off guideline cannot be recommended.     

One millimetre polytetrafluoroethylene (Gore-Tex) as a microvascular prosthesis: technique and early patency

We have described a technique for grafting 1 mm internal diameter polytetrafluoroethylene (Gore-Tex) to the rat femoral artery. By spatulating the ends of the recipient artery and completing the proximal anastomosis before commencing the distal one, gentle and accurate suture placement is assured. At a mean of 40 days postoperatively (range 35-42 days) 16 of 20 Gore-Tex grafts (80%) were patent compared with 17 of 20 autogenous femoral vein grafts (85%). Examination of the prosthetic grafts by light microscopy and scanning electron microscopy showed incomplete development of a cellular lining and some areas of neo-intimal hyperplasia. One millimetre Gore-Tex provides excellent early patency as a microvascular graft in this experimental setting but long term patency is still undetermined.     

Lack of diameter effect on short-term patency of size-matched Dacron aortobifemoral grafts.

This study examined the relationship between graft diameter and subsequent patency in 79 patients who received Dacron aortobifemoral bypass grafts for aortoiliac occlusive disease between 1985 and 1989. Sixty-five percent of these patients were men, 25% were diabetic, and 94% were smokers, with an average age of 62 years. Patients were followed for a mean interval of 24 months. Life-table survival was 92% at 3 years. All surviving patients showed "significant" postoperative improvement by use of Society for Vascular Surgery/International Society for Cardiovascular Surgery combined clinical and vascular laboratory criteria. There were three early and five late graft thromboses. Primary and secondary life-table patencies were 85% and 92%, respectively, at 3 years. Dacron bifurcation grafts were selected to match the size of native arteries. Patients receiving small diameter grafts, defined as 12 mm (n = 9) and 14 mm (n = 39), were compared with patients receiving large diameter grafts of 16 mm (n = 26) and 18 mm (n = 5). Small diameter grafts were more likely to be used in women (p less than 0.01), but patient groups were otherwise comparable with respect to age, smoking history, diabetes, outflow status, operative indications, type of proximal anastomosis (end-to-end or end-to-side), location of distal anastomosis (common femoral vs deep femoral), type of graft construction (knitted vs woven), and functional result. Graft diameter did not influence life-table patency, which was 84% for small and 87% for large diameter grafts at 3 years (p = 0.74). Furthermore, none of the other variables listed above influenced graft patency.(ABSTRACT TRUNCATED AT 250 WORDS)