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

A Novel Vascular Anastomotic Coupling Device for End-to-End Anastomosis of Arteries and Veins

OBJECTIVE

Hand-sutured (HS) techniques remain the gold standard for most microvascular anastomoses in microsurgery. HS techniques can result in endothelial lacerations and back wall suturing, leading to complications such as thrombosis and free tissue loss. A novel force-interference-fit vascular coupling device (FIF-VCD) system can potentially reduce the need for HS and improve end-to-end anastomosis. This study aims to describe the development and testing of a novel FIF-VCD system for 1.5 to 4.0 mm outside diameter arteries and veins.

METHODS

Benchtop anastomoses were performed using porcine cadaver arteries and veins. Decoupling force and anastomotic leakage were tested under simulated worst-case intravital physiological conditions. The 1.5 mm FIF-VCD system was used to perform cadaver rat abdominal aorta anastomoses.

RESULTS

Benchtop testing showed that the vessels coupled with the FIF-VCD system could withstand simulated worst-case intravital physiological conditions with a 95% confidence interval for the average decoupling force safety factor of 8.2 ± 1.0 (5.2 ± 1.0 N) and a 95% confidence interval for the average leakage rate safety factor of 26 ± 3.6 (8.4 ± 0.14 and 95 ± 1.4 μL/s at 150 and 360 mmHg, respectively) when compared to HS anastomotic leakage rates (310 ± 14 and 2,100 ± 72 μL/s at 150 and 360 mmHg, respectively). The FIF-VCD system was successful in performing cadaver rat abdominal aorta anastomoses.

CONCLUSION

The FIF-VCD system can potentially replace HS in microsurgery, allowing the safe and effective connection of arteries and veins. Further studies are needed to confirm the clinical viability and effectiveness of the FIF-VCD system.

Clinical application of magnetic anchor technique in laparoscopic cholecystectomy: the first retrospective study in China

Background and objectives

Magnetic anchor technique (MAT) is frequently used in laparoscopic cholecystectomy. However, there are few reports on its clinical application in China. In this study, we retrospectively analyzed the clinical application of MAT in laparoscopic cholecystectomy in China.

Materials and methods

25 patients (4 males, 21 females) who underwent laparoscopic cholecystectomy assisted by MAT at the First Affiliated Hospital of Xi'an Jiaotong University were enrolled from November 2020 to March 2021. Their records were retrospectively analyzed. The magnetic anchor device was independently designed and developed by the authors and consisted of the anchor magnet and magnetic grasping apparatus. Surgical time, intraoperative blood loss, intraoperative accidents, operator experience, postoperative incision pain score, postoperative complications, and other indicators were evaluated and analyzed.

Results

All patients successfully underwent laparoscopic cholecystectomy, including 3 cases of MAT-assisted transumbilical single-port LC, 16 cases of MAT-assisted 2-port LC and 6 cases of conventional 3-port LC. The median operation time was 50 min (range 30-95 min); intraoperative bleeding was less than 30 ml. The median score of surgical incision on day 1 and 3 after the operation was 3 (range 1-4) and 1 (range 1-3), respectively. All patients had no intraoperative bile duct injury, vascular injury, postoperative bleeding, bile leakage, biliary stricture and other complications. No adverse events (such as injury to adjacent organs or failure of the magnetic anchor device) occurred either during or after the operation.

Conclusions

The MAT-assisted laparoscopic cholecystectomy appears to be safe, feasible and effective and exhibits unique assistance in transumbilical single-port laparoscopic cholecystectomy.

Magnetic compression anastomosis for sigmoid stenosis treatment: A case report

BACKGROUND

Endoscopic balloon dilation is a minimally invasive treatment for colorectal stenosis. Magnetic compression anastomosis can be applied against gastrointestinal anastomosis. When combined with endoscopy, it offers a unique approach to the recanalization of colorectal stenosis.

CASE SUMMARY

We have reported here the case of a 53-year-old female patient who underwent a descending colostomy due to sigmoid obstruction. Postoperative fistula restoration was not possible in her due to sigmoid stenosis. Accordingly, endoscopic-assisted magnetic compression anastomosis for sigmoid stenosis was performed, and the sigmoid stenosis was recanalized 15 d after the surgery. Subsequently, a reduction colostomy was successfully performed after 10 d.

CONCLUSION

This case report proposes a novel minimally invasive treatment approach for colorectal stenosis.

Primary animal experiment to test the feasibility of a novel Y-Z magnetic hepatic portal blocking band

BACKGROUND

Hepatic portal blood flow occlusion is a common technique for reducing hepatic hemorrhage during hepatectomy. We designed a novel Y-Z magnetic hepatic portal blocking band (Y-Z MHPBB) based on the principle of magnetic compression technique.

AIM

To introduce the Y-Z MHPBB device and verify the feasibility of this device for hepatic portal blood flow occlusion in dogs.

METHODS

Ten beagles were randomly divided into the experimental group and control group. The operation time, intraoperative blood loss, the number of portal blood flow occlusions, the total time spent on adjusting the blocking band, and the average time spent on adjusting the blocking band were recorded. The surgeons evaluated the feasibility and flexibility of the two portal occlusion devices.

RESULTS

Laparoscopic hepatectomy was successfully performed in both the experimental group and control group. There was no statistical difference between the two groups in the operation time, intraoperative blood loss, and the number of hepatic portal blood flow occlusions. With respect to the total time spent on adjusting the blocking band and the average time spent on adjusting the blocking band, the experimental group showed significantly better outcomes than the control group, with a statistical difference (P < 0.05). The operators found that the Y-Z MHPBB was superior to the modified T-tube in terms of operational flexibility.

CONCLUSION

The Y-Z MHPBB seems to be an ingenious design, accurate blood flow occlusion effect, and good flexibility; and it can be used for hepatic portal blood flow occlusion during laparoscopic hepatectomy.

A systematic review of sutureless vascular anastomosis technologies

Vascular anastomoses typically involve a handsewn technique requiring significant surgical training, expertise, and time. The aim of our systematic review was to identify and describe sutureless vascular anastomosis techniques. We performed a systematic review of all sutureless vascular anastomosis technologies published in MEDLINE, PubMed, Embase, CINAHL, Cochrane, Web of Science, and Scopus Library databases and a patent review using US Patent and Trade Office Application, US Patent and Trademark Office Patent, Google Patents, Lens, Patent Quality Through Artificial Intelligence, SureChEMBL, and E-Space Net. Data from inclusion studies and patents published between January 1, 1980 and July 15, 2021 were abstracted to describe their category, anastomosis type and configuration, study types, and advantages and disadvantages encountered with each technology. Two hundred eleven original studies and 475 patents describing sutureless vascular anastomosis technologies were identified. In the literature, stents/stent-grafts/grafts (n = 61), lasers (n = 53), and couplers (n = 27) were the predominant device categories. In the patent review, adhesive technologies (n = 103), stents/stent-grafts/grafts (n = 68), and mechanical connectors (n = 61) predominated. The majority of studies involved in vivo animal studies (n = 193); 32.2% (n = 68) of investigations involved human trials; and 17.9% (n = 85) of patent technologies were approved by the US Food and Drug Administration. The main advantages described for sutureless anastomosis technologies included faster procedure time and greater patency rates compared with handsewn anastomoses. The main disadvantages included reduced vessel compliance, stenosis, leakage, and device costs. The appeal of sutureless technology is substantiated by numerous animal trials, but their use in humans remains limited. This may be a reflection of strict regulatory criteria and/or vascular complications associated with currently available technologies.

A different technique for sutureless coronary bypass grafting

Introduction

Many coronary anastomotic devices have been designed to replace manual stitching in coronary surgery; however, interestingly, none of them became widespread. Our aim was to work out an easy and fast endoluminal vessel-to-vessel stent bridge distal anastomotic technique.

Materials and methods

Ten coronary arteries of eight fresh human hearts were used in this study. The anastomosis was performed with the implantation of a graft vessel into the lumen of the coronary artery by performing stent fixation. The technique is described and photo documented in detail. The durability and the conductibility of the anastomosis were examined with intraluminal endoscopy, functional streaming test, and a coloring of the vessels.

Results

The anastomosis had great results in all cases. Obstruction, dissection, or dislocation of the vessels was not observable.

Conclusions

This study confirmed the ex-vivo feasibility of the described technique. This method can be an easy, fast, and reliable method applied in the endoscopic distal coronary artery anastomosis surgery. The development of stents adapted to this method and the in-vivo testing of this technique are necessary for the future.

Multicenter Assessment of Grafts in Coronaries: Midterm Evaluation of the C-Port Device (the MAGIC Study)

OBJECTIVE

The commercially available C-Port distal anastomotic device (Food and Drug Administration cleared in 2007) is an automated miniature vascular stapler that performs the coronary anastomosis. This prospective multicenter registry sought to evaluate midterm patency using this device compared with hand-sewn grafts.

METHODS

Patients receiving at least one C-Port anastomosis during coronary artery bypass grafting surgery were enrolled at eight sites. Of the 117 patients enrolled, 78 patients (67%) with 104 C-Port vein grafts completed the study to patency assessment via computed tomography angiography. Clinical follow-up and index graft patency (Gated 64-slice computed tomography scan) were performed at least 12 months postoperatively. The primary efficacy endpoint was patency compared with the peer-reviewed results from the PRoject of Ex-vivo Vein graft ENgineering via Transfection IV (PREVENT IV) trial.

RESULTS

The patient population was consistent with the PREVENT IV placebo cohort. The mortality at 12 months was 0.85% (1/117). The major cardiac morbidity rate was 3.4% (4/117). The C-Port vein graft occlusion rate was 16.3% (17/104) compared with 26.6% (597/2242) in the PREVENT IV trial (P = 0.011). Within this study, C-Port graft occlusion rates were not significantly different from the hand-sewn grafts (P = 0.821).

CONCLUSIONS

The C-Port device is safe and effective in creating the distal anastomosis with equivalent patency rates to hand-sewn grafts at 12 months. When compared with hand-sewn anastomoses from a recent large prospective trial, the C-Port device demonstrated a statistically significant reduction in midterm graft occlusion. Further studies are required to evaluate its effect in less invasive coronary surgery.

The C-Port Distal Coronary Anastomotic Device Is Comparable With a Hand-Sewn Anastomosis: Human Histological Case Study

Coronary artery bypass surgery is most commonly performed using a hand-sewn technique with a continuous monofilament suture. The C-Port distal anastomotic device is a miniature stapler designed to create an arteriotomy and attach the graft to the coronary artery all in one step. It is the only distal coronary anastomotic device currently approved for clinical use and can be useful in facilitating less invasive coronary surgery. This report examines the histological attributes of such an anastomosis in a patient who underwent heart transplantation approximately 1 year after robotic totally endoscopic stapled coronary bypass using the C-Port anastomotic device. There have been no previous reports of histological examination of this type of bypass graft in humans in the literature. We found that the C-Port single-shot stapled coronary anastomotic device had a similar histological appearance to a traditional hand-sewn technique using monofilament suture. The amount of inflammation around the anastomosis using the two techniques was found to be comparable in this histological case study in an explanted human heart. There was no evidence of increased neointimal hyperplasia. These findings add to the already known equivalent clinical patency rates of the C-Port device in coronary bypass procedures.

Does the Ventrica Magnetic Vascular Positioner (MVP®) for Coronary Artery Bypass Grafting Significantly alter Local Fluid Dynamics? a Numeric Study

Objective

Automatic devices have been recently introduced to make the anastomosis procedure quick and efficient when creating a coronary bypass on the beating heart. However, the implantation of these devices could modify the graft configuration, consistently affecting the hemodynamics usually found in the traditional anastomosis. As local fluid dynamics could play a significant role in the onset of vessel wall pathologies, in this article a computational approach was designed to investigate flow patterns in the presence of the Ventrica magnetic vascular positioner (Ventrica MVP®) device.

Methods

A model of standard hand-sewn anastomosis and of automated magnetic anastomosis were constructed, and the finite volume method was used to simulate in silico realistic graft hemodynamics. Synthetic analytical descriptors - i.e., time-averaged wall shear stress (TAWSS), oscillating shear index (OSI) and helical flow index (HFI) - were calculated and compared for quantitative assessment of the anastomosis geometry hemodynamic performance.

Results

In this case study, the same most critical region was identified for the 2 models as the one with the lowest TAWSS and the highest OSI (TAWSS=0.229, OSI=0.255 for the hand-sewn anastomosis; TAWSS=0.297, OSI=0.171 for the Ventrica MVP®). However, the shape of the Ventrica MVP® does not induce more critical wall shear stresses, oscillating flow and damped helicity in the graft fluid dynamics, as compared with conventional anastomosis.

Conclusions

We found that the use of the Ventrica MVP® for the case study under investigation was not associated with more critical fluid dynamics than with conventional hand-sewn anastomosis. Thereby, the device could facilitate beating heart and minimally invasive coronary artery bypass grafting without increasing local hemodynamic-related risks of failure. (Int J Artif Organs 2007; 30: 628–39)

Total Arterial Minimally Invasive Direct Coronary Artery Bypass Surgery Facilitated by the Trinity Clip Connector

OBJECTIVE

This pilot study evaluated the feasibility of total arterial minimally invasive direct coronary artery bypass surgery by using the Trinity Clip anastomotic connector in an acute porcine model.

METHODS

In 3 pigs, the left and right internal thoracic arteries (LITA and RITA) were harvested conventionally and the chest closed subsequently. After a left lateral thoracotomy, the coronary target was positioned and stabilized by an endo-starfish and octopus. A free RITA-to-LITA y-graft, with a LITA-to-left anterior descending coronary artery (LAD) and a free RITA-to-obtuse marginal or posterolateral or posterior descending artery, was constructed using the Trinity Clip. Patency was assessed with angiography (n = 3 anastomoses).

RESULTS

The anastomotic procedure was feasible via a small lateral thoracotomy, with a fast construction of the y-graft, and successful application of the mounted complex (ie, graft, connector, and laser, temporarily fixated by a fixation clip) onto the LAD. Access to the obtuse marginal artery, posterolateral artery, and posterior descending artery was possible, with successful construction, resulting in patent anastomoses.

CONCLUSIONS

This experimental pilot study demonstrates the feasibility of the anastomotic technique in a total arterial minimally invasive direct coronary artery bypass approach. Revascularization of the anterior, lateral, and inferoposterior regions of the heart is possible. However, visibility during the introduction of the connector was limited, and videoscopic assistance is essential to allow for successful construction. The anastomotic technique has potential to facilitate minimally invasive coronary bypass surgery.

A Laser-Assisted Anastomotic Technique: Feasibility on Human Diseased Coronary Arteries

OBJECTIVE

Atherosclerotic disease might hamper the efficacy of the Excimer laser-assisted Trinity Clip anastomotic connector in coronary arteries. Therefore, its efficacy was evaluated on human diseased coronary arteries (study 1). In addition, the acute laser effects onto the coronary wall were assessed (study 2).

METHODS

Thirty-eight anastomoses were constructed on ex vivo human hearts. Atherosclerosis was histopathologically determined and subsequently related to the success of the technique (ie, connector positioning and laser punching; study 1). In addition, 20 anastomoses were constructed in an ex vivo (porcine, n = 8) and an in vivo [rabbit (n = 9) and porcine (n = 3)] model. Subsequently, the coronary was histologically studied on the presence of laser-induced damage (study 2).

RESULTS

In 13 of 38 anastomoses (study 1), the connector was malpositioned, 3 because of a severely diseased coronary wall and 10 because of an inner diameter less than the intended target range. The laser-punch success rates on coronary arteries with an early and advanced lesion were 100% (16/16) and 89% (8/9; lesions were located in the inferolateral wall), respectively. In one case, an advanced lesion (ie, fibrocalcified plaque) was located in the superolateral wall and caused a laser-punch failure. No histological signs of laser-induced damage were observed, in case of correct use (study 2).

CONCLUSIONS

This study demonstrates the feasibility of an anastomotic connector on human diseased coronary arteries and shows that lasering does not induce coronary wall damage. However, careful selection of the coronary, regarding the target inner diameter and disease status, will prevent construction failures. This connector could facilitate less invasive coronary artery bypass grafting.

Optimization and Evaluation of a Vascular Coupling Device for End-to-End Anastomosis: A Finite-Element Analysis

Currently, end-to-end anastomosis of blood vessels is performed using suturing, which is time consuming, expensive, and subject to large degrees of human error. One promising alternative is a ring–pin coupling device. This device has been shown to be useful for venous anastomosis, but lacks the versatility necessary for arterial applications. The purpose of this study was to optimize a vascular coupling design that could be used for arteries and veins of various sizes. To achieve this, finite-element (FE) analysis was used to simulate the vessel–device interaction during anastomosis. Parametric simulations were performed to optimize the number of pins, the wing pivot point, and the pin offset of the design. The interaction of the coupler with various blood vessel sizes was also evaluated. Maximum strain in the vessel wall increased with the number of pins. The positions of the wings and pins were also important in dictating maximum strain, and improper dimensions lead to failure of the installation process. Extra force applied to the distal end of the vessel, or a supplementary tool, will be required during the coupler installation process to prevent vessels less than 3 mm inner diameter (0.5 mm wall thickness) from slipping off the coupler.

A New Vascular Coupler Design for End-to-End Anastomosis: Fabrication and Proof-of-Concept Evaluation

Traditional hand-suturing for vascular connection techniques is time consuming, expensive, and requires highly complex instruments and technical expertise. The aim of this study is to develop a new vascular coupler that can be used in end-to-end anastomosis surgery in an easier and more efficient way for both arteries and veins. The vascular coupler has four rotatable wings and one translatable spike in each wing. Prototypes were manufactured using polytetrafluoroethylene (PTFE) and high-density polyethylene (HDPE). A set of installation tools was designed to facilitate the anastomosis process. Proof-of-concept testing with the vascular coupler using plastic tubes and porcine cadaver vessels showed that the coupler should work as designed. A simplified finite element (FE) model assisted in the evaluation of the tearing likelihood of human vessels during installation of the coupler. Results of tests on the coupler showed that the vascular coupler could be efficiently attached to blood vessels, did not leak after the anastomosis was performed, had sufficient joint strength, and had little impact on flow in the vessel. The entire anastomosis process can be completed in 3 min when using the vascular coupler to join porcine cadaver vessels.

A systematic review of the safety and efficacy of distal coronary artery anastomotic devices

Interest in minimally invasive and off-pump cardiac surgical techniques has promoted the development of automated distal anastomotic devices (DADs) to facilitate construction of coronary artery anastomosis. Several DADs have been proposed for potential use in coronary surgery. However, a number of technical failures and uncertainty around both short-term morbidity and long-term patency have limited the generalized uptake of these devices. A systematic literature search identified 28 studies, incorporating 970 patients who underwent coronary artery bypass grafting using a DAD. Eight different devices were identified including Heartflo, St Jude, U-clip, vessel closure system, C-port, magnetic vascular positioner and coronary anastomosis coupler. Thirty-day mortality, cardiac-specific mortality and myocardial infarction were equal between DADs and hand-sewn cases (1.3, 0.3 and 0.8%, respectively). The overall proportion of postoperative haemorrhage was higher in the anastomotic device group (2.3%) than in the group with hand-sewn anastomoses (1.5%) although not statistically significant. Overall graft patency was 97.2% at <1 month, 94.6% at 1-3 months and 92.3% at >3 months. Of the currently available systems, the U-clip device was found to provide the best overall postoperative outcomes, which included a patency of 96.1% at >3months. The current literature is limited by its predominantly observational study design and lack of directly comparative studies. Furthermore, inter-study variation in patient selection, anticoagulation strategies and follow-up periods prevents quantitative comparison. Future research necessitates multicentre randomized, controlled studies to provide a direct comparison of current and future anastomotic device systems with established hand-sewn techniques in both the short and long term.

Design, fabrication, and testing of a novel end-to-end vascular coupling system

Microvascular anastomosis is common and necessary during reconstructive and free tissue transfer surgeries. Traditional hand suturing techniques are time consuming, subject to human error, and require complex instruments. Prior attempts including staples, ring-pin devices, cuffing devices, and clips were either more cumbersome, were unable to maintain a tight seal, or did not work for both arteries and veins. To provide a more efficient and reliable vessel anastomosis, a pin-free vascular coupling system that can be used for both arteries and veins was designed and manufactured. A set of corresponding instruments were developed to facilitate the anastomosis process. Both bench testing and ex vivo testing were performed to evaluate the operating abilities of the vascular coupling system. Preliminary studies were performed on cadaver pigs.

Evaluation of a novel laser-assisted coronary anastomotic connector - the Trinity Clip - in a porcine off-pump bypass model

To simplify and facilitate beating heart (i.e., off-pump), minimally invasive coronary artery bypass surgery, a new coronary anastomotic connector, the Trinity Clip, is developed based on the excimer laser-assisted nonocclusive anastomosis technique. The Trinity Clip connector enables simplified, sutureless, and nonocclusive connection of the graft to the coronary artery, and an excimer laser catheter laser-punches the opening of the anastomosis. Consequently, owing to the complete nonocclusive anastomosis construction, coronary conditioning (i.e., occluding or shunting) is not necessary, in contrast to the conventional anastomotic technique, hence simplifying the off-pump bypass procedure. Prior to clinical application in coronary artery bypass grafting, the safety and quality of this novel connector will be evaluated in a long-term experimental porcine off-pump coronary artery bypass (OPCAB) study. In this paper, we describe how to evaluate the coronary anastomosis in the porcine OPCAB model using various techniques to assess its quality. Representative results are summarized and visually demonstrated.

Anastomotic devices for coronary artery bypass grafting

With the advent of off-pump and minimally invasive coronary artery bypass grafting, efforts to facilitate construction of the graft to coronary anastomosis have increased. As a result, a number of anastomotic devices have been developed. While the ideal anastomotic device should be easy to use, produce a geometrically optimal anastomosis with minimal endothelial damage and minimal blood-exposed nonintimal surface, a number of design constraints apply. This review collects the available preclinical and clinical data for some of the devices, with special regard as to surgical outcome, patency rate and the need for additional perioperative anticoagulation treatment.

The nonocclusive laser-assisted coronary anastomotic connector in an off-pump porcine bypass model

OBJECTIVES

To facilitate minimally invasive coronary artery bypass grafting, a simplified alternative for hand-sutured anastomoses must be developed. We assessed the feasibility and anastomotic healing of the ameliorated Excimer laser-assisted nonocclusive anastomosis coronary prototype connector in an acute rabbit study (study 1) and in a long-term porcine off-pump coronary bypass study (study 2).

METHODS

Eighteen anastomoses were constructed on the abdominal aorta of the rabbit. In the porcine model, 15 left internal thoracic artery to left anterior descending coronary artery bypasses were evaluated intraoperatively and at 4 hours, 4 and 10 days, 2, 3, and 5 weeks, and 6 months (each n = 2 anastomoses). The anastomoses were examined by angiography, flow measurements, fractional flow reserve, coronary flow reserve, histologic features, and scanning electron microscopy.

RESULTS

In study 1, all 18 anastomoses were patent and resisted supraphysiologic pressures (n = 12, 300 mm Hg). In study 2, the connector enabled nonocclusive and fast (7.7 ± 2.2 minutes, mean ± standard deviation) anastomosis construction. All but 1 of 15 anastomoses (owing to a technical error) were fully patent (FitzGibbon grade A) at follow-up. Histologic examination and scanning electron microscopy demonstrated complete endothelialization of the anastomoses at 10 days. At 6 months, no flow-limiting but streamline-covering intimal hyperplasia was shown (fractional flow reserve, 0.93 ± 0.07 mean ± standard deviation).

CONCLUSIONS

The new nonocclusive coronary connector is easy to use, and the long-term results suggest favorable healing and remodeling in the porcine model. After downsizing, this anastomotic device, with its emphasis on zero ischemia and simplified prebounding of vessel walls, has intrinsic potential for minimally invasive off-pump coronary artery bypass surgery.

Nonsuture anastomosis of arteries and veins using the magnetic pinned-ring device: a histologic and scanning electron microscopic study

BACKGROUND

The goal of this study was to evaluate the performance of the magnetic pinned-ring device for nonsuture vascular anastomosis.

METHODS

The magnetic pinned-ring device consists of paired magnetic rings that are coated with titanium nitride and embedded in a polypropylene shell; the rings are equipped with alternately spaced holes and titanium pins. The vascular anastomosis procedure using the novel magnetic pinned-ring device was performed on 14 mongrel dogs, and the traditional hand-sewing technique was used on 14 additional dogs. In situ end-to-end anastomoses were performed in the femoral artery and the inferior vena cava. Patency was confirmed through ultrasonographic scans at different time points as late as 24 weeks after surgery. Gross observation, histological staining, and scanning electron microscopy were used to evaluate the results at 24 weeks postoperatively.

RESULTS

The time required to perform the vascular anastomosis was significantly shorter for the magnetic device than for hand sewing. A continuity of re-endothelialization was confirmed in all anastomotic stomas after 24 weeks, and neither formation of aneurysms nor thickening of the vascular wall was noted. The re-endothelialization was smooth at the anastomotic site of the magnetic device, whereas hand sewing resulted in rough and uneven re-endothelialization and the presence of visible sutures. Moreover, the endothelial cells were regularly arranged at the anastomotic site of the magnetic device, whereas different-sized and irregularly aligned endothelial cells were present at the hand-sewn anastomotic site. Use of the magnetic device was associated with significantly decreased deposition of fibrotic collagen and depressed infiltration of inflammatory cells compared with use of the hand-sewing technique.

CONCLUSIONS

The magnetic pinned-ring device offers a simple, fast, reliable, and efficacious technique for nonsuture vascular anastomosis. Use of this device shortens operation time, maintains a high patency rate, and improves the healing of vascular tissue.

A new nonocclusive laser-assisted coronary anastomotic connector in a rabbit model

OBJECTIVE

The Excimer laser-assisted nonocclusive anastomotic technique is a nonocclusive, facilitated bypass technique that is currently Conformité Européenne and Food and Drug Administration approved for clinical application in neurosurgery. In the present study, we assessed the safety and feasibility of a newly developed Excimer laser-assisted nonocclusive anastomosis-based prototype coronary anastomotic connector in an acute rabbit abdominal aortic bypass model before application in experimental coronary bypass surgery. In addition, 2 sealants were tested to facilitate anastomotic hemostasis in the current device prototype.

METHODS

A total of 40 anastomoses were constructed on the abdominal aorta (3.5 mm outer diameter) of 10 rabbits. The anastomotic circumference was sealed by a surgical sealant to obtain complete hemostasis (BioGlue vs TachoSil). The anastomoses were evaluated by flow measurements construction time, hemostasis, histologic analysis, and burst pressure testing.

RESULTS

The connector enabled a nonocclusive and fast (6.0 ± 1.7 minutes, mean ± SD [including sealing]) anastomosis construction and complete hemostasis in 95% (35/37). Sealing with BioGlue was faster than with TachoSil (19% vs 53% of construction time). Despite technical imperfections (7/40 failures to completely retrieve the flap by the laser), all 40 anastomoses were patent, showed reproducible construction with intima-adventitia apposition, streamlining thrombus coverage of the intraluminal laser rim, and no vessel wall damage. All anastomoses resisted ex vivo supraphysiologic pressures (> 300 mm Hg).

CONCLUSIONS

The results of the present study have demonstrated that the Excimer laser-assisted nonocclusive anastomotic connector is safe and reliable and can be efficiently applied in an acute rabbit abdominal aortic bypass model. Provided the limitations can be addressed, this easy-to-use and nonocclusive technique has the potential to facilitate minimally invasive coronary bypass surgery.

Totally Endoscopic Magnetic Enteral Bypass by External Guided Rendez-Vous Technique

Objective. This study aimed to assess the feasibility of a totally endoscopic enteral bypass using a self-orienting, dual ring, magnetic anastomosis system (MAGNAMOSIS) guided by a magnetic tracking system (3D METRIS). Materials and methods. In an anesthetized pig, 2 endoscopes were advanced, one each into the stomach and the colon. Both endoscopes were equipped with a MAGNAMOSIS ring secured with an endoscopic snare and a 3D METRIS within one working channel. The whole procedure was followed laparoscopically. The tracking system guided tips of endoscopes to a “rendez-vous” location between the colon and stomach. Results. MAGNAMOSIS magnets automatically joined in the correct configuration when guided to within 2 cm of each other. At necropsy, magnetic rings were secure without entrapment of excess bowel or mesentery. Conclusion. An endoscopic enteral bypass with magnetic anastomosis and magnetic tracking device was feasible. More accurate tracking and advanced techniques could enable endoscopic bypasses at multiple sites in the gastrointestinal tract.

Retraction by surface ferromagnetisation of target tissues: preliminary studies on feasibility of magnetic retraction for endoscopic surgery

BACKGROUND

Magnetic retraction has potential advantages over existing direct physical retraction means (e.g., forceps) in terms of providing complete atraumatic retraction, avoiding tumour cell exfoliation as well as offering the possibility of noncontact retraction. This paper describes a pilot study of surface magnetic retraction of the gastric mucosa to facilitate resection.

METHODS

Fifteen porcine stomach specimens were used in this pilot study. The uniaxial tensile properties of retracted mucosa were initially studied using a tensiometer. Magnetic media of ferromagnetic microparticles (stainless steel 410) dispersed in cyanoacrylate liquid were prepared at four different concentrations, and a neodymium permanent magnet was used to magnetically retract the media. The media was finally surface-glued to the target mucosa for performing a simulated surgical procedure.

RESULTS

The force measurement data show that the retraction forces increased as the concentrations of microparticles and magnetic media volumes increased. A magnetic media concentration of 2 g/mL was most suitable since it offered sufficient retraction force from a small volume of applied media, e.g., the observed magnetic forces exerted on 50 microL of media were 1.42 N by a 3-mm magnet and 3.75 N by a 6-mm magnet, respectively, both being more than sufficient for the mucosal retraction. The additional forces required for dissection with four alternative instruments, i.e., electrosurgery hook, snares, scalpel or scissors, were also measured, e.g., the total force required to retract up to 10 mm and resect the mucosa with snares was 0.36 +/- 0.17 N. In a simulated surgical procedure (resection of gastric mucosa with glued magnetic medium) retraction by the magnet allowed resection of the tented mucosa by an electrosurgical snare.

CONCLUSION

Surface ferromagnetisation of target mucosal tissues could enable magnetic retraction for endoscopic surgery.

Revival of the side-to-side approach for distal coronary anastomosis

Side-to-side anastomosis was employed by just ten proportional stitches while performing distal anastomosis during coronary artery surgery. This technique is simple and quick. Here this simple technique is described in detail and the postoperative status of grafted conduits is reported.

Coronary artery bypass with the use of a magnetic distal anastomotic device: surgical technique and preliminary experience

BACKGROUND

At present there is little reported experience in the application of new technology in the performance of distal coronary anastomoses in the clinical setting. The aim of our study was to evaluate the feasibility of using the Ventrica magnetic vascular positioner (MVP) device for left internal thoracic artery (LITA)-to-left anterior descending (LAD) coronary anastomosis.

METHODS

We present our preliminary experience of the first 14 coronary artery cases performed in the United Kingdom from April 2003 to December 2003. The selection criteria, surgical technique, clinical outcome, advantages or disadvantages, and future implications are all discussed.

RESULTS

The device was used in 12 patients for LITA-to-LAD anastomosis and in 2 patients for the proximal anastomosis of a radial artery Y-graft from the LITA to the circumflex territories. The first 3 patients underwent coronary artery bypass graft with the use of cardiopulmonary bypass, and the remaining 9 underwent surgery performed using an off-pump coronary artery bypass technique. No mortality or device-related events were observed in these patients. The anastomosis time in our series was 5.6 +/- 1.99 minutes, and the blood loss was 914 +/- 234 mL. The mean length of stay was 5.8 +/- 1.16 days.

CONCLUSION

The MVP system is a novel distal coronary anastomotic device that is quick, simple, and effective, producing consistently reliable coronary anastomoses in a wide variety of coronary bypass procedures. Early results are encouraging, and further studies are required in order to evaluate long-term efficacy of this system in the rapidly changing world of coronary revascularization.

Experimental Study of Aortic Anastomosis Using a Circular Stapling Device in the Porcine Model

OBJECTIVES

The aim of this study was to assess the strength (pressure resistance) and histological findings of aortic anastomoses performed using a circular stapling device.

MATERIALS AND METHODS

A circular stapling device was used for anastomosing a porcine aorta and a Dacron graft. The maximum pressure resistance of the anastomotic site of a porcine aortic specimen and a Dacron graft was examined (n=10). A porcine aorta with Dacron graft was anastomosed to a beating heart, and pressure overload was induced by adrenaline (n=5). Specimens of the anastomotic sites were harvested after 14 days and examined histologically.

RESULTS

The maximum pressure resistance of the anastomotic site was 427.3+/-34.4 (375-511) mmHg. No anastomotic sites leaked as a result of pressure overloading at 227.6+/-21.1 (201-260) mmHg. Histologically, good incorporation and cell coverage were observed, and the inner surfaces of the anastomotic sites were smooth and without stenoses.

CONCLUSIONS

Aortic anastomosis using a circular stapling device is feasible and worthy of further investigation.

The Cardica C-Port System: Clinical and angiographic evaluation of a new device for automated, compliant distal anastomoses in coronary artery bypass grafting surgery—A multicenter prospective clinical trial

OBJECTIVES

The C-Port System (Cardica, Inc, Redwood City, Calif) integrates in one tool all functions necessary to enable rapid automated distal coronary anastomoses. The goal of this prospective, nonrandomized, and multicenter study is to determine the safety and efficacy of this novel anastomotic system.

METHODS

Five centers enrolled 133 patients awaiting elective coronary artery bypass grafting surgery. Outcome variables were intraoperative device performance, incidence of device-related adverse events, predischarge and 6-month angiographic graft patency, and 12-month clinical outcome. Independent core laboratories performed qualitative and quantitative angiographic and computed tomographic assessments.

RESULTS

The C-Port was used to perform a vein-to-coronary anastomosis in 130 patients. Intraoperative conversion to a hand-sewn anastomosis was necessary in 11 patients because of inadequate target site preparation, inappropriate target vessel selection, or both. Inadequate blood flow related to poor runoff required conversion in 3 additional patients. Three patients died before discharge of causes unrelated to the device. At discharge, 113 patients had a C-Port implant in place, and 104 C-Port anastomoses were studied by means of angiography, resulting in 100 FitzGibbon A, 3 FitzGibbon B, and 1 FitzGibbon 0 classifications. At 6 months, one additional patient died of a device-unrelated cause, and 98 patients were evaluated by means of angiography (n = 89). Overall patency (FitzGibbon A) was 92.1%. Three C-Port anastomoses were rated FitzGibbon B, and 4 were rated FitzGibbon 0. At 12 months, 107 (98.2%) of 109 alive patients were followed up, without any reports of device-related major adverse cardiac events.

CONCLUSIONS

The C-Port System allows for a rapid, reliable, and compliant distal anastomosis and yields favorable 6-month angiographic and 12-month clinical results when compared with published studies.

Magnetic Vascular Port in minimally invasive direct coronary artery bypass grafting

BACKGROUND

Minimally invasive direct coronary artery bypass grafting (MIDCAB) is a well-established operative procedure. However, it is technically demanding and is therefore somewhat underused. We evaluated the clinical and angiographic outcome of patients undergoing a MIDCAB procedure with the Ventrica Magnetic Vascular Port (MVP) system.

METHODS AND RESULTS

A Ventrica MVP system was used in 10 of 11 selected MIDCAB patients. The system consists of 6 magnetic clips, with 3 clips forming a set. One magnetic clip set is positioned at the arteriotomy of the target artery and of the bypass graft using a preloaded delivery system. These ports then form an anastomosis by magnetic coupling. The mean age of the 10 patients (6 male) was 60.3+/-11.0 years. Three patients had an angiogram at the time of discharge and 8 returned for a 6-month angiogram. The total procedure time was 128.2+/-12.2 minutes. The mean anastomotic time was 199 seconds. The mean ischemic time during the anastomosis was 146+/-146 seconds. There were no in-hospital complications and no device-related adverse events. All 3 predischarge and all 8 6-month angiograms showed patent anastomoses.

CONCLUSIONS

The magnetic vascular port facilitates the MIDCAB procedure significantly and reduces the ischemic time during the anastomosis. This minimally invasive procedure has the potential to be an alternative to percutaneous transluminal coronary angioplasty and stenting in proximal left anterior descending (LAD) stenosis. It may expand the acceptance of hybrid procedures in which a left internal mammary artery (LIMA)-to-LAD graft optimally supplies the anterior wall and the septum while the circumflex and right coronary artery may be treated interventionally.

Initial Experience of an Automated Anastomotic Distal Device in Off-Pump CABG

BACKGROUND

Recent progress in minimally invasive technology in the field of coronary artery bypass grafting (CABG) stimulates interest in anastomotic devices used to facilitate distal coronary anastomosis. We assessed the feasibility of the automated anastomotic distal device (AADD) on arterial grafts in patients who underwent off-pump CABG (OPCAB) and evaluated the early anastomotic patency and clinical results of the AADD based on an elliptical nitinol ring with attached 8 pins.

METHODS

Fourteen patients scheduled for multivessel OPCAB using arterial grafts between August 2003 and February 2004 were studied. Among 19 patients enrolled, 5 patients were excluded: 2 patients because of failure of graft flaring onto the implant pins, 2 because of small and diseased target coronary artery (<1.5 mm in diameter), and 1 because of conversion to cardiopulmonary bypass. The distal anastomosis using the AADD was performed for the nondominant coronary artery.

RESULTS

The total number of distal anastomoses was 48 (34 hand-sewn sutures and 14 AADD sutures), and the average number of distal anastomoses per patient was 3.4 +/- 1.0. The grafts used for the AADD were right gastroepiploic artery (RGEA) in 10 patients, saphenous vein anastomosed to the end of the RGEA in 2 patients, and internal thoracic artery in 2 patients. The average time required for distal anastomosis using the AADD (from arteriotomy to anastomosis completion) was 2.9 +/- 0.7 minutes (range, 1.5-4 minutes). The mean flow and pulsatility index of the AADD grafts measured intraoperatively by transit time flow measurement were 20.0 +/- 10.3 mL/min and 2.4 =/- 1.2, respectively. Early postoperative coronary angiographies demonstrated widely patent grafts in 32 of 34 hand-sewn anastomoses and 13 of 14 AADD sutures. There were no adverse events related to the use of the device.

CONCLUSIONS

Our initial experience demonstrated that distal anastomosis using the AADD was feasible in most of the patients who underwent OPCAB using arterial grafts. Distal anastomosis using the AADD had the advantage of shortening the actual suturing duration and might provide a method for standardizing the anastomotic procedure.