Laser-assisted Vascular Anastomosis Research Articles

A novel technique for laser-assisted revascularization: an in vitro pilot study.

The common limitation of surgical revascularization procedures for severe tissue ischemia due to cardiovascular diseases is the need to interrupt blood flow during the intervention. We aim to introduce a new technique that allows a sutureless, non-occlusive revascularization. A 3-step technique was developed using rabbit's aorta to simulate a side-to-side anastomosis model. It enables the creation of a bypass circuit for revascularization. The first step was the soldering of 2 vessels in a side-to-side fashion based on the laser-assisted vascular anastomosis (LAVA) principle using a diode laser emitting irradiation at 810 nm with an albumin-based solder patch between them, followed by the creation of a channel within the patch using either a holmium-doped yttrium aluminum garnet laser (Ho:YAG) at λ = 2100 nm or a xenon-chloride excimer laser (XeCl) at λ = 308 nm. Thereby, a bypass circuit was created, thus allowing a non-ischemic revascularization. The system was deemed functional when a flow was observed across the anastomosis. The highest average tensile strength recorded after side-to-side LAVA using a diode laser power of 3.2 W for 60 s was 2278.6 ± 800 mN (n = 20). The Ho:YAG laser created the channels with less tension on the anastomosis than the excimer laser. Histological analysis showed limited thermal damage and good patch-tissue adaptation. The preliminary results of this feasibility study outline the foundations for an entirely sutureless laser-assisted revascularization procedure. The next studies will evaluate the rheological parameters across the bypass circuit to optimize the post-anastomotic flow.

Laser-Assisted Microvascular Anastomosis of Free Flaps in Reconstruction of Orofacial Defects: A Comparative Study Among Conventional Methods and Diode Laser Anastomosis.

The key role played by anastomosis determines the outcome of any free flap surgery. Besides many methods, the application of LASERS for performing microvascular anastomosis gaining popularity in recent times. The ease of application, utilizing lesser time for performing anastomosis than the conventional methods and minimal injury to the vessel layers, are contributing factors to the success of free flap surgery. Laser-assisted vascular anastomosis (LAVA) fulfills the criteria of lesser vessel wall damage and faster anastomosis and thus resulting in reduced flap ischemic time and overall outcome of the surgery. A prospective randomized case-control trial comparing conventional suturing methods (group I) with Laser-assisted vascular anastomosis (group II) on free flaps were performed for the reconstruction of orofacial defects. The parameters assessed for evaluation were anastomotic time, ischemic time and vessel patency following anastomosis. Student's t test and Fisher's exact tests were implied for statistical analysis. The mean time taken for anastomosis was 19.75min in the conventional group and 3.86min in LAVA anastomosis. This difference was found to be extremely statistically significant (p < 0.00001). The mean ischemic time of the free flap harvested was 384.87min in group I and 138.7min in group II. This difference was also found to be extremely statistically significant (p < 0.00001). The average anastomosis time for LAVA group was considerably reduced and total ischemic time was considerably less with successful uptake of the flap. In LAVA group, the post-operative complication was less when compared to the conventional anastomosis technique.

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

AimThe aim of the study is to compare the advantages and disadvantages of non-suturing anastomotic methods over conventional microsuturing for microvascular venous anastomosis. Materials and methodsAll patients reporting to the institute for hard and soft tissue reconstruction (Primary/secondary) were enrolled in the study. Patients with systemic comorbidities, peripheral vascular diseases, or anatomical aberration of the indicated donor site were excluded from the study. The patients selected for the study were randomly allocated to five groups of different techniques of venous anastomosis, namely Group I (conventional microsuturing), II (fibrin sealant reinforced microsuturing), III (couplers), IV (staplers), V (Laser Assisted Vascular Anastomosis (LAVA)). Intraoperative anastomotic time, flap ischaemic time, patency and leakage were the parameters that were assessed for all five groups. Results80 Patients were randomly allocated to five groups and each group comprised 16 patients. The mean ischaemic time and standard deviation of Group I and Group II were 256.19 ± 10.622 min and 255.19 ± 11.083 min, and for groups III, IV, and V were 193.38 ± 9.972 min, 139.06 ± 6.413 min, and 139.31 ± 6.364 min respectively (p < 0.001). Mean anastomotic time and standard deviation were 19.813 ± 1.5366 min in Group I and 20.281 ± 1.6514 min in Group II. The non-sutured anastomosis groups III, IV, and V showed a mean anastomotic time of 5.375 ± 0.9876 min, 4.175 ± 0.7664 min, and 3.856 ± 0.867 min respectively (p value < 0.001). In Groups I and II, 18.8% of patients had delayed patency and in Groups III, IV and V, immediate patency was observed in all subjects (p value 0.030). In Groups I and II, 18.8% and 6.3 % of patients respectively had leakage, whereas all patients in Groups III, IV, V had no leakage from the anastomotic site (p value 0.119). ConclusionBased on the results of the study, non-suturing techniques should be preferred over microsuturing technique whenever appropriate for venous anastomosis.

Sutureless Microvascular Anastomosis: Literature Review

Traditionally, suturing techniques have been the mainstay for microvascular anastomoses, but owing to its technical difficulty and labour intensity, considerable work has gone into the development of sutureless microvascular anastomoses. In this review, the authors take a brief look at the developments of this technology through the years, with a focus on the more recent developments of laser-assisted vascular anastomoses, the unilink system, vascular closure staples, tissue adhesives, and magnets. Their working principles, with what has been found concerning their advantages and disadvantages are discussed.

Electrospinning of highly concentrated albumin patches by using auxiliary polymers for laser-assisted vascular anastomosis

Background and objective. Electrospun meshes have been extensively investigated for tissue engineering and drug delivery. The application of this technology is of interest for laser-assisted vascular anastomosis (LAVA) due to the possibility to bind and stabilize macromolecules in fibers. Materials and methods. We prepared bovine serum albumin (BSA) blend microfibers from the auxiliary proteins polyethylene oxide (PEO), polycaprolactone (PCL), polyvinyl alcohol (PVA) and gelatin. The thickness and weight of the resulting patches were measured and the morphological characteristics were observed by scanning electron microscopy. Thereafter, layered patches were prepared by spinning the BSA/polymer layer on top of a light absorbing layer made of indocyanine green and PCL. The effect of the material composition of the electrospun patches on the behavior during LAVA, the bonding strength and the resulting thermal damage were investigated. Results. The bonding strength of the tissue fusion increased with higher BSA amounts in the patch. By using PEO, a ratio of 85/15 (w/w) of BSA/PEO was stable during electrospinning, leading to a shear strength that was similar to patches that were soaked in liquid BSA (20.7 ± 4.1 mN mm−2 and 20.3 ± 4.1 mN mm−2, respectively). The handling during LAVA was however drastically improved by using a layered patch made from BSA/PEO. Thermal damage was similar compared to previous solder materials. Conclusion. This study investigated the maximum amount of BSA possible in electrospun polymer fibers made from PEO, PCL, PVA and gelatin. Both, the process of electrospinning and the performance during ex vivo LAVA, makes the BSA/PEO blend a promising material for LAVA.

Binding of indocyanine green in polycaprolactone fibers using blend electrospinning for in vivo laser-assisted vascular anastomosis.

The clinical application of laser-assisted vascular anastomosis is afflicted by unreliable and low bonding strengths as well as tedious handling during microvascular surgery. The challenge to be met arises from the flow-off of the chromophore during soldering that changes the absorption and stains the surrounding tissue, leading to an uncontrollable thermal damage zone. In this study, we investigated the feasibility to produce an indocyanine green (ICG)-loaded patch by electrospinning and tested its applicability to both in vitro and in vivo microvascular laser soldering. A blend of polycaprolactone and ICG was electrospun to produce a pliable patch. Prior to soldering, the patch was soaked in 40% wt. bovine serum albumin solution. The solder patch was wrapped in vitro around blood vessel stumps of rabbit aortas. An intraluminal balloon catheter enabled an easy alignment and held the setup in place. The soldering energy was delivered via a diffusor fiber from the vessel lumen using a diode laser at 810 nm. During the procedure, the surface temperature was observed with an infrared camera. Afterward, samples were embedded in methylmethacrylate and epon to study thermal damage. The quality of the fusion was assessed by measuring the tensile strength. After in vitro tests with rabbit aortas, eight large white pigs were subjected to an acute in vivo experiment, and the artery of the latissimus dorsi flap was anastomosed to the distal femoral artery. The ICG-loaded patch, produced by electrospinning, has a thickness of 279 ± 62 μm, a fiber diameter of 1.20 ± 0.19 μm, and an attenuation coefficient of 1,119 ± 183 cm-1 at a wavelength of 790 nm. The patch was pliable and easy to handle during surgery. No leakage of the chromophore was observed. Thermal damage was restricted to the Tunica adventitia and Tunica media and the area of the vessel wall that was covered with the patch. Six pigs were successfully treated, without any bleeding and with a continuous blood flow. The in vivo flap model yielded a similar tensile strength compared to in vitro laser-assisted vascular anastomoses (138 ± 52 vs. 117 ± 30 mN/mm2 ). Our study demonstrated the applicability of the ICG-loaded patch for laser-assisted vascular anastomosis. By using electrospinning, ICG could be bound to polymer fibers, avoiding its flow-off and the staining of the surrounding tissue. This patch demonstrated several advantages over liquid solder as it was easier to apply, ensured a high and reliable bonding strength while maintaining a constant concentration of ICG concentration during the surgery. Lasers Surg. Med. 49:928-939, 2017. © 2017 Wiley Periodicals, Inc.

Endoluminal laser-assisted vascular anastomosis-an in vivo study in a pig model.

Microvascular surgery is time consuming and requires high expertise. Laser-assisted vascular anastomosis (LAVA) is a promising sutureless technique that has the potential to facilitate this procedure. In this study, we evaluate the handling of our soldering material and the 1-week patency rate in a porcine model. Six pigs were subjected to LAVA. For each pig, the saphenous artery on one side was transected while the contralateral side was used as control. A porous polycaprolactone scaffold soaked in 40% (w/w) bovine serum albumin solution in combination with 0.1% (w/w) indocyanine green was wrapped at the anastomosis site and at the control site. Both sides were then soldered with a diode laser coupled into a light diffuser fiber emitting radiation with a wavelength of 808nm and a power of 2-2.2W. Vessels were successfully soldered with a 100% immediate patency rate. The 1-week patency rate was 83% for the anastomoses versus 67% for the control side. Vessels irradiated for 80 to 90s tended to maintain the highest patency rate. Macroscopically, there was no difference between the two sides. The patch was easy to handle provided that the environment could be kept dry. This study shows the potential and the limitations of endoluminal LAVA as a one-step procedure without the use of stay sutures. Further studies are needed to improve the soldering material, the long-term patency rate, and standardized irradiation parameters. The long-term effects of laser soldering on the vessel wall remain to be determined.

Ex vivo proof-of-concept of end-to-end scaffold-enhanced laser-assisted vascular anastomosis of porcine arteries

The low welding strength of laser-assisted vascular anastomosis (LAVA) has hampered the clinical application of LAVA as an alternative to suture anastomosis. To improve welding strength, LAVA in combination with solder and polymeric scaffolds (ssLAVA) has been optimized in vitro. Currently, ssLAVA requires proof-of-concept in a physiologically representative ex vivo model before advancing to in vivo studies. This study therefore investigated the feasibility of ex vivo ssLAVA in medium-sized porcine arteries. Scaffolds composed of poly(ε-caprolactone) (PCL) or poly(lactic-co-glycolic acid) (PLGA) were impregnated with semisolid solder and placed over coapted aortic segments. ssLAVA was performed with a 670-nm diode laser. In the first substudy, the optimum number of laser spots was determined by bursting pressure analysis. The second substudy investigated the resilience of the welds in a Langendorf-type pulsatile pressure setup, monitoring the number of failed vessels. The type of failure (cohesive vs adhesive) was confirmed by electron microscopy, and thermal damage was assessed histologically. The third substudy compared breaking strength of aortic repairs made with PLGA and semisolid genipin solder (ssLAVR) to repairs made with BioGlue. ssLAVA with 11 lasing spots and PLGA scaffold yielded the highest bursting pressure (923 ± 56 mm Hg vs 703 ± 96 mm Hg with PCL ssLAVA; P = .0002) and exhibited the fewest failures (20% vs 70% for PCL ssLAVA; P = .0218). The two failed PLGA ssLAVA arteries leaked at 19 and 22 hours, whereas the seven failed PCL ssLAVA arteries burst between 12 and 23 hours. PLGA anastomoses broke adhesively, whereas PCL welds failed cohesively. Both modalities exhibited full-thickness thermal damage. Repairs with PLGA scaffold yielded higher breaking strength than BioGlue repairs (323 ± 28 N/cm(2) vs 25 ± 4 N/cm(2), respectively; P = .0003). PLGA ssLAVA yields greater anastomotic strength and fewer anastomotic failures than PCL ssLAVA. Aortic repairs with BioGlue were inferior to those produced with PLGA ssLAVR. The results demonstrate the feasibility of ssLAVA/R as an alternative method to suture anastomosis or tissue sealant. Further studies should focus on reducing thermal damage.

Optimization of Suture-Free Laser-Assisted Vessel Repair by Solder-Doped Electrospun Poly(ε-caprolactone) Scaffold

Poor welding strength constitutes an obstacle in the clinical employment of laser-assisted vascular repair (LAVR) and anastomosis. We therefore investigated the feasibility of using electrospun poly(ε-caprolactone) (PCL) scaffold as reinforcement material in LAVR of medium-sized vessels. In vitro solder-doped scaffold LAVR (ssLAVR) was performed on porcine carotid arteries or abdominal aortas using a 670-nm diode laser, a solder composed of 50% bovine serum albumin and 0.5% methylene blue, and electrospun PCL scaffolds. The correlation between leaking point pressures (LPPs) and arterial diameter, the extent of thermal damage, structural and mechanical alterations of the scaffold following ssLAVR, and the weak point were investigated. A strong negative correlation existed between LPP and vessel diameter, albeit LPP (484 ± 111 mmHg) remained well above pathophysiological pressures. Histological analysis revealed that thermal damage extended into the medial layer with a well-preserved internal elastic lamina and endothelial cells. Laser irradiation of PCL fibers and coagulation of solder material resulted in a strong and stiff scaffold. The weak point of the ssLAVR modality was predominantly characterized by cohesive failure. In conclusion, ssLAVR produced supraphysiological LPPs and limited tissue damage. Despite heat-induced structural/mechanical alterations of the scaffold, PCL is a suitable polymer for weld reinforcement in medium-sized vessel ssLAVR.

Suture-free laser-assisted vessel repair using CO2 laser and liquid albumin solder

Numerous studies have shown that the use of proteinic solders during laser-assisted vascular anastomosis (LAVA) and repair (LAVR) can significantly increase welding strength, but these studies combined solder-mediated LAVA/R with the use of stay sutures, thereby defeating its purpose. In an in vitro study, we examined the leaking point pressures (LPPs) and histological damage profile of porcine carotid arteries following albumin solder-mediated CO(2) LAVR without the use of sutures. Longitudinal arteriotomies (9.1+/-0.8 mm in length) were sheathed with 25% liquid bovine serum albumin solder, and LAVR was performed using a micromanipulator-controlled CO(2) laser operating at 170-mW power and 1.25-mm spot size in continuous wave mode. The welding regime consisted of a transversal zigzag pass followed by one or two longitudinal zigzag passes, producing an irradiance of 13.9 W/cm(2) and energies of 10.5 J and 11.3 J per mm weld, respectively. LPPs were measured by the fluid infusion technique, and histological analysis was performed with light, fluorescence, and polarization microscopy. The LPP of the two-pass welds was 351+/-158 mmHg versus 538+/-155 mmHg for the three-pass welds. Thermal damage was confined primarily to the adventitial layers, with limited heat diffusion into the media below the solder around the coaptation interface.

Laser-assisted vascular end to end anastomosis of elastin heterograft to carotid artery with an albumin stent: a preliminary in vivo study.

Laser-assisted end to end vascular anastomosis of an elastin heterograft to native artery may prevent problems associated with currently available vascular synthetic grafts and conventional suture anastomosis. A total of 21 anastomoses in the carotid arteries of 7 domestic swine were performed with an 800 nm laser and an albumin stent plus solder. There were 5 artery to artery and 16 elastin heterograft to native artery anastomoses. Operative parameters, vascular patency, and histology of the anastomoses were evaluated. Out of 21 anastomoses, 16 were patent for 3 hours. One artery to artery anastomosis was thrombosed and four elastin heterograft to artery anastomoses were excluded from the study due to heterograft burst. The average amount of applied energy was 212 J for artery to artery anastomosis and 273 J for elastin heterograft to native artery. Histology shows coagulative necrosis of the adventitia, hypereosinophilic contraction band in the media of native arteries and no changes in elastin heterografts. Laser-assisted vascular anastomosis (LAVA) of elastin heterograft to medium size vessel using an albumin stent is feasible. Chronic studies are warranted to determine long-term patency and histology of the LAVA.

Optimal dye concentration and irradiance for laser-assisted vascular anastomosis.

This investigation was done in order to find optimal indocyanine green (ICG) concentration and energy irradiance in laser vascular welding. Many studies have shown that laser tissue welding with albumin solder/ICG may be an effective technique in surgical reconstruction. However, there are few reports regarding optimal laser settings and concentrations of ICG within the albumin solder in laser-assisted vascular anastomosis. Porcine carotid artery strips (n = 120) were welded in end-to-end by diode laser with 50% albumin solder of 0.01, 0.1, and 1.0 mM ICG at irradiance of 27.7, 56.7, and 76.9 W/cm(2), respectively. Temperature was measured by inserting thermocouples outside and inside the vessel. Tensile strength and histology were studied. Temperature and strength of the anastomosis significantly decreased (all p < 0.05) with increasing ICG concentration at 56.7 W/cm(2). Histological study showed minimal thermal injury limited to adventitia and no appreciable difference between all groups. ICG concentration within solder is the most important factor affecting both vascular temperature and tensile strength. The optimal balance between strength and minimal thermal injury may be achieved primarily at 56.7 W/cm(2) and 0.01 mM ICG.

Methylene blue based protein solder for vascular anastomoses: an in vitro burst pressure study.

Attempts at sutureless anastomoses have used protein-based solders containing chromophores [Oz et al., J Vasc Surg 1990;11:718; Poppas et al., J Urol 1998150:1052] to enhance the strength of laser anastomoses. Reports have described the use of indocyanine green [Oz et al., Surg Forum 1989;316.], fuschin, and fluorescein isothiocyanate as chromophores [Chuck et al. , Lasers Surg Med 1989;9:471; Vance et al., Lasers Med Sci 1988;3:219]. Methylene blue (MB) is a chromophore with absorption peaks in the 600-700 nm region whose use has not been reported in laser-assisted vascular anastomoses. Therefore, we set out to produce and characterise a MB-containing protein solder. The absorption and burst pressure characteristics have been investigated and described as well as a brief review of the chemical and biological properties of MB. The MB and porcine serum albumin (PSA)-based solder was produced and used to form end-to-end anastomoses in porcine splenic arteries. The solder was activated using a laser diode emitting at 670 nm. The burst pressures of the anastomoses were tested, and the results analysed as a function of MB concentration and absorption. In addition, the relationship between MB concentration and absorption was examined. A dose-response relationship was found between the measured absorption of the solder and the burst pressure of the anastomoses formed. Burst pressures exceeding physiological levels were found. Changes in MB concentration revealed a marked negative deviation from Beer's law at 670 nm, owing to the monomer-dimer-trimer equilibria. PSA with MB solder is able to form high-quality end-to-end anastomoses, with immediate burst pressure profiles similar to those previously described for sutured [Quigley et al., Microsurgery 1985;6:229], lasered [Quigley et al., Microsurgery 1985;6:229], and soldered anastomoses [Small et al., J Clin Laser Med Surg 1997;15:205]. The relationship between burst pressure strength and chromophore absorption is discussed.

Comparison of laser vascular welding, interrupted sutures, and continuous sutures in growing vascular anastomoses

The argon laser-assisted vascular anastomosis may solve the problems of conventional sutured anastomosis, such as vascular stenosis and arrest of growth owing to a foreign-body reaction to suture material. Twelve argon laser-assisted vascular anastomoses, seven conventional anastomoses with interrupted sutures, and five conventional anastomoses with continuous sutures were performed in 12 young mongrel dogs. Five months later, the external diameter at the anastomosis had increased 70.5% in the laser group, 67.0% in the interrupted suture group, and 22.9% in the continuous suture group. Histological examination of the laser-assisted anastomoses showed almost complete healing, with no granulomatous response around the anastomotic site. In the interrupted suture group, marked scaring and foreign body reactions were observed on the vessel wall at the site of the anastomosis. The continuous suture group showed more remarkable disorientation of the vascular layer and intimal hyperplasia than the interrupted suture group. Vascular anastomosis using the argon laser offers advantages over the conventional procedure in growing vessels.

肝臓外科におけるレーザー血管吻合

ラット70%肝切除が, 動脈吻合部創傷治癒に及ぼす影響を顕微鏡下に行ったレーザー吻合と従来の手縫い吻合とで比較検討した。レーザー吻合は, 吻合部耐圧力, 動脈瘤出現率において手縫い吻合と有意差無く, 吻合部石灰化出現率に関しては, レーザー吻合の方が有意に低値を示した。以上の結果より, レーザー吻合は, 拡大肝切除術時においても血管吻合の有用なオプションの一つになりうると推察された。レーザー吻合を肝臓外科手術, 特に肝臓移植に導入するにあたっては, 口径, 壁の厚さ, 性状の違う血管の吻合をいかに行うかという問題の解決が必要である。

組織コラーゲン動態から見たレーザー血管吻合部の創傷治癒

レーザー血管吻合部の創傷治癒を客観的に評価するために, 健康雑種成犬の総頸動脈に作製した吻合部のコラーゲン量, 非コラーゲン蛋白質量およびコラーゲン濃度を, 色素結合法により測定し, 手縫い吻合部を対照にその経時的 (直後, 7日, 15日, 30日, 60日, 90日, 各=5) 変化を観察した。レーザー吻合部では, コラーゲン量およびコラーゲン濃度が吻合後急増し, 15日をピークに30日以降吻合直後の値に回復した。手縫い吻合部においては, 漸増し, 60日まで高値を持続した。その結果, レーザー血管吻合では, 手縫い吻合よりも良好で早い創傷治癒が得られた。

A comparison of absorbable suture and argon laser welding for lateral repair of arteries

Conventional vascular anastomoses between autogenous vessels are performed with nonabsorbable sutures. Recently, use of absorbable sutures and laser-assisted vascular anastomoses has been advocated because of their improved healing characteristics. This study compared arterial repairs with the argon laser, absorbable suture, and nonabsorbable suture for technical characteristics including additional suture and overall success rates, burst strength, and cost. Absorbable and nonabsorbable suture closures were comparable with respect to technique, but laser-assisted vascular anastomosis was technically more demanding and required almost twice as much time for completion. The argon laser successfully closed only 58.6% of the arteriotomies, and 90% of the closures required additional sutures for complete hemostasis. All sutured arteriotomies were successfully completed by use of either absorbable or nonabsorbable suture. Burst strength was similar for all groups, but was uniformly greater than 300 mm Hg for sutured repairs, whereas two of five laser-assisted closures burst below 300 mm Hg. Finally, costs for purchasing ($35,000) and operating ($300/hr.) an argon laser make laser-assisted vascular anastomosis much more expensive than sutured repair. These data suggest argon laser-assisted vascular anastomoses are more technically demanding, less successful, and more expensive than conventional sutured anastomoses when evaluated in large caliber arteries in a canine model. Absorbable suture, however, is comparable to conventional nonabsorbable sutured arterial repairs in expense, handling characteristics, and success rates with the added advantage of eliminating permanent foreign body in the arterial wall when it is absorbed.

Internal Mammary Coronary Artery Anastomosis by Co2Laser: An Acute Experimental Study

This study was designed to determine the feasibility of anastomosing the internal mammary artery (IMA) and coronary artery with a carbon dioxide laser in a canine model. Twenty-two mongrel dogs were randomly assigned to two groups: group I (n = 11) underwent laser-assisted vascular anastomosis (LAVA) of the left IMA to the left anterior descending (LAD) coronary artery, whereas in group II (n = 11) the anastomosis was done with the conventional technique (handsewn). Laser methodology was used to micro-weld vessels utilizing a power of 200 mW with a spot size of 500 mu, producing an effective power density of 102 W/cm2 and energy fluence of 9,172 joules/cm2 in a continuous mode at a distance of 2 cm. The short-term patency rate, measured at 2 hours after completion of the anastomosis, was 100% in both groups. The time required to perform the LAVA in group I was significantly shorter than group II (6.27 +/- 0.47 vs 11.6 +/- 0.67 min, p less than 0.05). The mean anastomotic bursting pressure in group I was significantly lower compared to group II (348 +/- 8 vs 402 +/- 9 mmHg, p less than 0.05). Histologic evaluation of all vessels showed moderate thermal injury of the adventitia and media in the laser group. Scanning electron microscopy exhibited a smooth anastomotic area in group I, whereas endothelial and perianastomotic changes with multiple needle craters occurred in group II (conventional anastomosis).(ABSTRACT TRUNCATED AT 250 WORDS)

Microvascular end-to-side arterial anastomosis using the Nd

End-to-side, laser-assisted vascular anastomosis (LAVA) using a Nd: YAG laser was successfully performed on rat carotid arteries. A midline neck incision allowed isolation and approximation of both carotid arteries in an end-to-side fashion using four 10-0 nylon stay sutures. The laser parameters used for vessel fusion were 0.3-second 5-W pulses at a spot size of 600 microns. Anastomoses were analyzed at various time intervals from 1 day to 6 months by angiogram and histological examination. The anastomotic patency was 86%. Aneurysm formation occurred in 23%. Histological examination revealed an acute/subacute transmural injury both at the anastomotic site and several hundred microns away, with delayed re-endothelialization and some attempt at muscular and elastic regeneration. Histological assessment of the aneurysms demonstrated a total loss of the internal elastic lamina and muscularis. A brief discussion comparing Nd: YAG LAVA to other LAVA techniques follows.

Microvascular End-to-Side Arterial Anastomosis Using the Nd: YAG Laser

Abstract End-to-side, laser-assisted vascular anastomosis (LAVA) using a Nd:YAG laser was successfully performed on rat carotid arteries. A midline neck incision allowed isolation and approximation of both carotid arteries in an end-to-side fashion using four 10-0 nylon stay sutures. The laser parameters used for vessel fusion were 0.3-second 5-W pulses at a spot size of 600 Mm. Anastomoses were analyzed at various time intervals from 1 day to 6 months by angiogram and histological examination. The anastomotic patency was 86%. Aneurysm formation occurred in 23%. Histological examination revealed an acute/subacute transmural injury both at the anastomotic site and several hundred microns away, with delayed re-endothelialization and some attempt at muscular and elastic regeneration. Histological assessment of the aneurysms demonstrated a total loss of the internal elastic lamina and muscularis. A brief discussion comparing Nd:YAG LAVA to other LAVA techniques follows.