Robotically assisted coronary artery bypass grafting: a prospective single center clinical trial.

AIM: This prospective study was performed as a Phase 1 Food and Drug Administration clinical trial to assess the safety and feasibility of robotically assisted coronary artery bypass grafting (CABG). METHODS: Eighteen patients undergoing elective CABG were enrolled in this study. Full sternotomy was performed in 17 of 18 patients, while cardiopulmonary bypass and cardioplegic arrest was used in all cases. Robotically assisted CABG of the left internal thoracic artery (LITA) to the left anterior descending artery (LAD) was performed through three ports using a robotically assisted microsurgical system. Conventional techniques were used to perform all other grafts. Blood flow in the LITA graft was measured in the operating room, and when necessary, angiography was performed. Six weeks after the operation, all patients underwent selective coronary angiography of the LITA graft. RESULTS: Robotically assisted coronary artery anastomoses were successfully completed in all patients. Blood flow through the LITA graft was adequate in 16 of 18 patients (89%). The two inadequate grafts were revised successfully by hand. Six weeks after the operation, angiography demonstrated a graft patency of 100% (13 of 13). Mean follow-up has been over 190 days. All patients remain New York Heart Association Angina Class I. CONCLUSION: Robotic assistance represents an enabling technology that may allow the surgeon to perform endoscopic coronary artery anastomoses. Further clinical trials are needed to explore the clinical potential and value of robotically assisted CABG.     

Prospective clinical trial of robotically assisted endoscopic coronary grafting with 1-year follow-up

OBJECTIVE: To follow up in prospective fashion patients with coronary artery anastomoses completed endoscopically with robotic assistance. The robotic system was evaluated for safety and its effectiveness in completing microsurgical coronary anastomoses. SUMMARY BACKGROUND DATA: Recently there has been an interest in using robotics and computers to enhance the surgeon's ability to perform endoscopic cardiac surgery. This interest has stemmed from the rapid advancement of technology and the desire to make cardiac surgery less invasive. Using traditional endoscopic instruments, it has not been possible to perform coronary surgery. METHODS: Nineteen patients underwent robotically assisted endoscopic coronary artery bypass grafting of the left internal thoracic artery (LITA) to the left anterior descending artery (LAD). Two robotic instruments and one endoscopic camera were placed through three 5-mm ports. A robotic system was used to construct the LITA-LAD anastomosis. All other required grafts were completed by conventional techniques. RESULTS: Seventeen LITA-LAD grafts (89%) had adequate intraoperative flow. The mean LITA-LAD graft flow was 38.5 +/- 5 mL/min. At 8 weeks, LITA-LAD grafts were assessed by angiography and showed 100% patency with thrombolysis in myocardial infarction (TIMI) I flow. At a mean follow-up of 17 +/- 4.2 months, all patients were NYHA class I and there were no adverse cardiac events. CONCLUSIONS: The results from the first prospective clinical trial of robotically assisted endoscopic coronary bypass surgery in the United States showed favorable short-term outcomes with no adverse events. Robotic assistance is an enabling technology allowing the performance of endoscopic coronary anastomoses.     

Robotically enhanced minimally invasive direct coronary artery bypass surgery: a winning strategy?

AIM: Minimally invasive direct coronary artery bypass (MIDCAB) through a small anterolateral thoracotomy on the beating heart can be considered as the better approach for treating isolated lesions on the left anterior descending (LAD) artery. This original MIDCAB procedure, however, involves a larger and often painful thoracotomy due to rib spreading. We describe our experience with robotically enhanced harvesting of one or both internal mammary arteries (IMAs), and with anastomosis performed under direct vision on a beating heart through a very small thoracotomy without rib retraction. METHODS: Between February 2001 and January 2006, 146 consecutive patients underwent robotically enhanced MIDCAB surgery. Perioperative and early follow-up data were analyzed. RESULTS: In all, 144 left and 13 right IMAs were harvested. The mean extubation time was 11.3 h, the mean intensive care (ICU) stay was 30.3 h, the mean hospital stay 8 days. There were no in-hospital deaths, postoperative myocardial infarctions or renal failures. Systematic control angiograms performed in the first 64 patients showed a 96.3% patency rate of the investigated anastomoses. CONCLUSION: Robotically assisted takedown of the IMA and direct off-pump anastomosis through a small anterolateral thoracotomy with no rib retraction appears to be safe, with minimal morbidity, little blood loss, and a reasonable ventilation time, ICU and hospital stay. It is recommended as the preferred method of revascularization for a growing number of indications and certainly an acceptable alternative to percutaneous transluminal coronary angioplasty.     

Transfer of training in robotic-assisted microvascular surgery

BACKGROUND: Transfer of training refers to the ability to transfer acquired skills from one discipline to another. This study aims to determine whether experience in traditional freehand microsurgery facilitates mastery of robotic microsurgery. METHODS: Microsurgical anastomoses of coronary arteries harvested from explanted pig models were used to demonstrate whether prior experience with microsurgery is required in learning robot-assisted microsuturing. Eighty microsurgical anastomoses were performed. Three fully trained vascular surgeons (n = 3) (Group A) and 5 midlevel surgical residents (n = 5) (Group B) performed the anastomoses. Each subject performed 5 freehand and 5 robotic-assisted (Zeus robotic system) anastomoses. Anastomosis time and integrity of anastomoses were recorded, including errors of management (EOM) (breaking suture, breaking knots, breaking or damaging needles). RESULTS: For fully trained surgeons, all anastomoses in the robotic-assisted group were mechanically intact. There was significantly increased anastomosis time with the robot (Robot: 14 minutes, versus freehand: 7.2 minutes, P < 0.01). The robotic-assisted anastomoses were associated with a higher EOM (Robot: 1.2, versus freehand: 0.3, P < 0.01).Surgical trainees had longer anastomosis times with robotic assistance (Robot: 14.8 minutes, versus freehand, 12.7 minutes; P < 0.01) and increased EOM (Robot: 1.6, versus freehand: 1.0; P < 0.05).Overall, surgical trainees and fully trained vascular surgeons had longer anastomotic times with robotic assistance [Robot: 14.0 versus 14.8 minutes; P = not significant (NS)], and EOM (Robot: 1.6, versus freehand: 1.2; P = NS) were not significantly different. CONCLUSION: The technical feasibility of performing a safe and efficient robotic-assisted microsurgical anastomosis in explanted vessels was repeatedly tested and demonstrated in this study within reasonable time required for the anastomosis. Compared with conventional microanastomosis, both fully trained surgeons and residents demonstrated an ability to master the robotically assisted procedure with similarly longer anastomosis times and EOM. This study indicates that robotically assisted microanastomosis can be mastered equally well by surgical trainees and fully trained vascular surgeons.     

Results of a Phase One study on robotically assisted myocardial revascularization on the beating heart

Background

The objective of this study was to evaluate the feasibility of computer assisted myocardial revascularization on the beating heart.

Methods

Ten patients underwent at least one robotically assisted internal mammary artery (IMA) anastomosis utilizing the da Vinci surgical system (Intuitive Surgical, Inc, Mountain View, CA) performed through an open incision as part of standard multivessel off pump revascularization. Following chest closure a selective IMA angiogram was performed to assess patency. Three month follow-up included a stress echocardiogram.

Results

There were 12 anastomoses performed in 10 patients. The average age was 61 years with a mean ejection fraction of 56%. No patient required inotropic support. Eight of 10 patients were found to have fully patent IMA anastomoses by angiogram. One patient was noted to have an occluded left anterior descending coronary artery distal to the anastomosis and one had occlusion at the anastomosis. Both patients had immediate manual revision of the anastomosis. One patient who required anastomotic revision experienced postoperative myocardial infarction and sternal wound infection requiring pectoralis flaps.

Conclusions

Because robotic instrumentation is meant for closed chest procedures, there were major issues with positioning of the robotic arms in this study since the chest was open. Although two patients required anastomotic revision, there were no complications or technical failures related to the robotic system. Thus, based upon this study robotically assisted beating heart revascularization appears to be feasible, safe, and effective. Further evaluation will be necessary to determine the role of robotically assisted totally endoscopic coronary artery bypass on the beating heart in the United States.     

Patency rates of three arterial grafting patterns to the left anterior descending and diagonal coronary arteries in symptomatic patients

BACKGROUND: The use of internal thoracic arteries is an established method for treating coronary artery disease because of their excellent long-term patency rates. However, these results mainly referred to the left internal thoracic artery (LITA) grafted to the left anterior descending coronary artery (LAD). The aim of this study was to compare the patency rate of the LITA after its placement to the diagonal branch. METHODS: A total of 302 patients (median age 65 years) with previous arterial revascularization were retrospectively enrolled in the study. We compared LITA grafts to the LAD with those to the diagonal branch and with sequential LITA grafts to both vessels with respect to the patency rate over a median follow-up of 39 months after prior operation. Angiography was performed for recurrent angina. RESULTS: The average occlusion/stenosis rate of saphenous vein and LITA grafts were 43.1% and 14.1%, respectively (p < 0.0001). Of the 302 patients, 248 had received a single LITA graft to the LAD; 21 patients, a single LITA graft to the diagonal branch; and 33 patients, a sequential LITA graft to both vessels. Thirty-three LITA grafts to the LAD (13.3%), three LITA grafts to the diagonal branch (14.3%), and six sequential LITA grafts to the LAD and the diagonal branch (18.2%) were occluded or stenosed more than 50%, respectively (p = 0.68). Seventy-nine percent of LITA graft stenoses were located at the peripheral anastomosis. CONCLUSIONS: Patency of single LITA grafts to the diagonal branch or sequential LITA grafts to the LAD and diagonal branch were comparable to single LITA grafts to the LAD. Most stenoses of LITA grafts were located at peripheral anastomoses.     

Use of the voice-controlled and computer-assisted surgical system ZEUS for endoscopic coronary artery bypass grafting.

OBJECTIVE: With the aim of performing a completely endoscopic coronary bypass anastomosis, we have undertaken an experimental and clinical study using robotic instrumentation and voice-controlled camera guidance. METHODS: The ZEUS Robotic Surgical System (Computer Motion Inc, Goleta, Calif) consists of three interactive robotic arms and a control unit, allowing the surgeon to move the instrument arms in a scaled down mode. The third arm (AESOP, Computer Motion) positions the endoscope via voice control. PHASE I: In a phantom model, vascular grafts were anastomosed to the left anterior descending coronary artery (LAD) of 50 pig hearts with either 2- or 3-dimensional visualization. PHASE II: In 6 dogs (FBI 20-25 kg) the left internal thoracic artery (LITA) was harvested endoscopically. Then the animals were placed on an endovascular cardiopulmonary bypass system (Port-Access, Heartport, Inc, Redwood City, Calif). Anastomosis of the LITA to the LAD was performed endoscopically with the telemetric ZEUS instruments. Flow rates through the LITA were measured by Doppler analysis. PHASE III: Two patients were operated on with the ZEUS system. After endoscopic harvesting of the LITA and cardiopulmonary bypass with the Port-Access system, the bypass graft (LITA-LAD) was anastomosed endoscopically with the ZEUS system through three thoracic ports. RESULTS: In the dry laboratory, the time range required for the robotically assisted coronary anastomosis was 35 to 60 minutes with 2-dimensional visualization and 16 to 32 minutes with 3-dimensional visualization. In the animal experiments, the median time for endoscopic harvesting of the LITA was 86 minutes (range 56-120 minutes) and for the anastomosis, 42 minutes (range 35-105 minutes); flow rates through the LITA ranged between 22 and 45 mL/min. In the clinical cases, preparation times for the LITA were 83 and 110 minutes, respectively, and anastomosis times, 42 and 40 minutes, respectively. Doppler flow rates measured 125 and 85 mL/min, respectively. Both patients had an uneventful follow-up angiogram and postoperative course. CONCLUSIONS: With sophisticated robotic technology, a completely endoscopic anastomosis of the LITA to the LAD is possible, allowing technically precise operations within acceptable time limits.     

Intraoperative color Doppler ultrasound assessment of LIMA-to-LAD anastomoses in off-pump coronary artery bypass grafting

BACKGROUND: Although techniques for off-pump coronary artery bypass grafting (CABG) are continually being refined, angiographic follow-up studies have indicated a higher rate of anastomoses-related stenoses than expected after traditional on-pump CABG. This study was performed to evaluate the use of intraoperative epicardial color Doppler ultrasound to quality-assess left internal mammary artery (LIMA) to left anterior descending coronary artery (LAD) anastomoses performed on the beating heart. METHODS: Twenty-four LIMA-to-LAD anastomoses were evaluated with real-time epicardial ultrasound imaging using an ultrasound transducer positioned between the paddles of the stabilizer during off-pump procedures. The length of the anastomosis (D(A)), diameters of LIMA (D(M)), LAD at the toe of the anastomosis (D1), and 5 mm distally to the anastomosis (D2) were measured, and the ratios between these variables were calculated. The flow velocity through the anastomoses was visualized by color Doppler coding, and flow was assessed with transit-time flowmetry. RESULTS: The epicardial color Doppler ultrasound allowed accurate assessment of the anastomoses. Twenty-three (96%) of the primary anastomoses were confirmed as patent. Mean ratios of D1/D2, D(A)/D2, and D(M)/D2 were 0.89 +/- 0.13, 3.01 +/- 1.04 and 1.32 +/- 0.32, respectively. One anastomosis had a stenosis more than 50% detected by color Doppler ultrasound. After surgical revision, transit-time flow increased from 22 to 40 ml/min. CONCLUSIONS: Intraoperative color Doppler ultrasound allowed adequate imaging for quality assessment of LIMA-to-LAD anastomoses performed on the beating heart. One anastomosis was revised due to a technical error detected by epicardial color Doppler imaging. Epicardial ultrasound scanning is a valuable tool for intraoperative assessment of LIMA-to-LAD anastomoses during off-pump coronary surgery.     

Beating-heart totally endoscopic coronary artery bypass grafting: Report of a case

This case report presents beating-heart totally endoscopic coronary artery bypass grafting (TECAB) for single-vessel coronary artery disease. A 72-year-old man with isolated left anterior descending (LAD) coronary artery disease was considered eligible for TECAB. Left internal thoracic artery (LITA) mobilization and subsequent off-pump revascularization applying the LITA to the LAD in a closed chest environment was performed using the da Vinci surgical system (Intuitive Surgical, Mountain View, CA, USA). The LITA was first harvested completely in a totally skeletonized fashion through three incisions 1–2 cm long in the left thoracic wall. The LAD was immobilized with the aid of a heart stabilizer. The LITA was then anastomosed to the LAD with 10 interrupted sutures of a Nitinol self-closing S15 U-clip device (Medtronic, Minneapolis, MN, USA) on the beating heart without the use of cardiopulmonary bypass. The time acquired to perform anastomosis was 20 min, and the total operative time was 5 h 34 min. The postoperative course was uneventful and the patient was discharged 5 days after the operation. Beating-heart TECAB was successfully performed for this patient with single-vessel LAD disease. This approach may be an evolutionary step toward beating-heart multivessel TECAB.     

Early results of complete off-pump coronary revascularization using left internal thoracic artery with composite radial artery

Objective: Off-pump coronary artery bypass (OPCAB) using the left internal thoracic artery (LITA) with a composite radial artery (RA) was employed for arterial revascularization in order to minimize neurological complication. Methods: Sixty-one patients underwent OPCAB using the LITA with a composite RA. Angiography was performed in all patients at two weeks postoperatively. Results: The mean number of distal anastomoses was 3.2±0.4 A Y-composite graft was used in 55 patients, and K-composite graft was used in the other 6 patients. There was no hospital death, no neurological complication nor deep sternal infection Furthermore, there was no episode of perioperative myocardial infarction nor hypoperfusion syndrome. Patients have been angina-free during a mean follow-up period of 1 year. The graft patency of the LITA to the left anterior descending artery (LAD) was 100% (61/61 anastomoses). The RA became occluded in 4 patients, and the patency rate was 95.6% (130/136 anastomoses). String or coronary-coronary bypass resulting from flow competition was observed in the LITA of 6 patients and in the RA of 13 patients. The string of the LITA occurred in the segment distal from the anastomosis with the composite RA. The string or coronary-coronary bypass was observed more often in cases in which the recipient coronary artery had less than 75% stenosis. Conclusion: OPCAB using only the LITA with a composite RA can be successfully and safely performed in patients with multivessel disease. Late postoperative follow-up of the flow competition is necessary to delineate the significance of flow competion.     

Early experience of coronary artery bypass grafting with a new self-closing clip device

OBJECTIVE: We are in the midst of development of several new anastomotic devices for use in coronary artery bypass grafting surgery. This study was designed to examine one of these devices (a new self-closing clip) for left internal thoracic artery-left anterior descending coronary artery anastomosis. Its feasibility and the quality of anastomosis were evaluated. METHODS: Fourteen patients who underwent first-time elective coronary artery bypass surgery were enrolled between July and December 2000. The left internal thoracic artery was anastomosed to the left anterior descending coronary artery in an interrupted manner with Coalescent U-clips (Coalescent Surgical, Inc, Sunnyvale, Calif). Immediate patency was checked with a transit-time flowmeter. Selective angiography was performed 6 months after surgical intervention. RESULTS: Five patients underwent on-pump coronary bypass grafting, 9 on the beating heart. One patient was excluded from the study intraoperatively because of a poor target site necessitating a 2-cm-long anastomosis. Left internal thoracic artery-left anterior descending artery anastomoses were created with an average of 11.8 clips in 15.9 minutes. Mean graft flow was 45.6 mL/min. Neither conversion to standard suture technique nor revision of anastomosis was necessary. There tended to be a learning curve in the anastomosis on the beating heart. Postoperative lengths of stay in the intensive care unit and the hospital were 20.7 hours and 3.9 days, respectively. Neither death nor major complication was seen, except for temporary atrial fibrillation in 2 patients. Graft patency at 6 months was 100% (FitzGibbon grade A). CONCLUSION: Left internal thoracic artery-left anterior descending artery anastomoses can be created safely and effectively with new self-closing clips on the beating, as well as the arrested, heart. Midterm patency was shown to be perfect by means of angiography.     

Near infrared fluorescence imaging with ICG in TECAB surgery using the da Vinci Si surgical system in a canine model

Abstract Background: This study assessed the clinical utility of near‐infrared fluorescence imaging using indocyanine green in off‐pump beating heart total endoscopic and robotic‐assisted coronary artery bypass using the fluorescence imaging system for the da Vinci Si on a canine model for vessel identification, graft patency, and correlation of graft patency with ultrasound transit‐time flow measurement probe. Methods: Beating heart total endoscopic robotic‐assisted coronary artery bypass was performed on eight canine using indocyanine green and fluorescence imaging to identify the internal mammary artery prior to harvesting, the coronary vessel anatomy, and the patency of the beating heart total endoscopic coronary artery bypass anastomosis. Three to four injections of indocyanine green with a dose of 1.25 mg to 2.5 mg were administered per animal. Transit‐time flow was measured in each of the dogs. Results: High definition 3D images were obtained. The camera working distance, indocyanine green dosage, internal mammary artery visualization, coronary artery visualization, patency by indocyanine green injection, and patency by transit‐time flow were recorded. Six cases were completed successfully, and all demonstrated correlation between indocyanine green measurements of flow, and the transit‐time flow measurement. Conclusion: Use of near‐infrared fluorescence with indocyanine green was feasible in our study, and would be of great benefit during total endoscopic robotic‐assisted coronary artery bypass using the fluorescence imaging–capable da Vinci Si system to help identify the internal mammary artery, delineate the coronary anatomy, and also determine patency of the anastomoses. This procedure correlated well with transit‐time flow measurement.     

An experimental model of coronary anastomosis without suturing

OBJECTIVE: The aim of the study is to explore the feasibility and mid-term patency of an easier anastomotic technique for Minimally Invasive Direct Coronary Bypass Grafting (MIDCAB). METHODS: Eight mongrel dogs (+/-15 kg) underwent direct anastomosis between the left internal thoracic artery (LITA) and the left anterior descending coronary artery (LAD) via inferior sternotomy on the beating heart. After positioning the graft, the distal part of the LAD was opened to allow retrograde filling of the LITA-graft. The anastomosis was secured by the use of biological glue (BioGlue, Cryolife, Marietta, GA, USA). No intravascular suture material was used. Ischemic time averaged 6 min. The proximal LAD was occluded upstream the arteriotomy. All survivors were angiographically controlled for patency after 6-8 weeks. Consequently, four dogs were sacrificed after 6 weeks and the remaining after 3 months for anatomo-pathological and histological examination by light and electron microscopy of the anastomotic site. RESULTS: All procedures were successful except for one animal that died of uncontrollable bleeding at the anastomotic site. Another sustained post-operative transmural anterior myocardial infarction due to a late graft occlusion. All angiographically controlled grafts were patent with two vascular strings near the anastomotic site. Histology showed early macrophage infiltration into the glue. At post-mortem examination, new endothelialization was noticed in 80% of the cases. However, ultrastructural examination detected marked differences in endothelial fibroblastic lining compared to normal histology. CONCLUSIONS: Good mid-term permeability of the LITA grafts was observed in this new anastomotic technique for MIDCAB in the canine model. Although neo-endothelialization was present in most cases, ultrastructural differences were noticed after 3 months in the neo-intima compared to normal.     

Functional and perfusional assessment with electrocardiograph-gated single photon emission computed tomography after minimally invasive direct coronary artery bypass grafting.

BACKGROUND: Because of limited surgical field, minimally invasive coronary artery bypass grafting (MIDCAB) requires anastomosis to the distal portion of the left anterior descending artery (LAD) of the left internal thoracic artery (LITA) with the heart beating. Though the diameters of these arteries are very small, it is unknown whether blood flow sufficient for the LAD territory is obtained by bypass grafting. METHOD: Eight patients with single-vessel disease of the LAD underwent MIDCAB with the LITA to the LAD and we evaluate the perfusion and function in the LAD territory by quantitative ECG-gated SPECT (QGS) with 99m-technetium sestamibi (MIBI) before and after operation. RESULT: The intraoperatively measured diameters of the LITA and LAD at the site of anastomosis were 1.1+/-0.2 mm and 1.3+/-0.4 mm, respectively. The percentage increases in end-diastolic perfusion, regional ejection fraction and regional wall thickening in the anteroseptal area after MIDCAB were 136.3+/-11.7(p=0.071), 148.4+/-6.6(p=0.007) and 133.0+/-5.6(p=0.029), respectively (paired t-test, mean +/- SD %). Stress-rest MIBI SPECT indicated no ischemia in anteroseptal wall. CONCLUSION: The MIDCAB technique thus appeared to improve perfusion and function in the LAD territory despite bypass to the distal LAD, and ECG-gated MIBI SPECT using QGS software was very useful for evaluating the quality of anastomosis after MIDCAB.     

机器人非体外循环冠状动脉旁路移植术

目的 总结使用da Vinci S机器人系统完成的微创机器人非体外循环冠状动脉旁路移植术(CABG)的技术特点和临床效果.方法 2007年4月至2008年12月,共有56例患者接受微创机器人非体外循环CABG.所有患者术前均有心绞痛症状,冠状动脉造影显示严重的前降支病变,10例患者合并有回旋支或右冠状动脉病变.其中25例患者有心肌梗死病史.心功能(NYHA分级)Ⅱ级45例,Ⅲ级11例,平均射血分数为57%±11%.所有患者肺功能良好,无胸膜炎和左侧胸腔手术史.术前常规行64排CT检查双侧胸廓内动脉(ITA)的解剖情况.共采用三种术式:(1)机器人单侧或双侧ITA游离并同期小切口非体外循环CABG;(2)全机器人非体外循环CABG;(3)对合并有回旋支或右冠状动脉局限性狭窄的患者,接受上述两种术式的一种后行分站式支架置入杂交术.行单支或多支CABG时于左侧胸壁第4肋间做长6 cm的小切121,直视、心脏跳动下行ITA和前降支的吻合;行全机器人非体外循环CABG时无需胸壁切口.术后以冠状动脉造影或64排CT评估桥血管的通畅性,并进行随访.结果 所有患者成功接受了上述手术.术中平均ITA桥血流量为(23.2±16.7)mL/min,无中转开放手术和手术死亡.ITA移植到前降支53例,双支桥3例,其中10例患者旁路移植后接受了回旋支或右冠状动脉的支架植入杂交术.术后复查未见桥血管狭窄或闭塞.结论 微创机器人非体外循环CABG手术效果确实、可靠,不破坏胸腔骨性结构、创伤小,是微创CABG的发展方向之一.     

Facilitated coronary anastomosis using a nitinol U-Clip device: bovine model

OBJECTIVE: The coronary anastomosis is the most difficult part of the coronary bypass procedure, particularly when using a minimally invasive technique. Methods to facilitate coronary anastomosis will make the minimally invasive approach to coronary bypass feasible. We sought preclinical validation and testing of the design and efficacy of a self-closing penetrating clip that can be used to facilitate the creation of graft-to-coronary end-to-side anastomosis. METHODS: The nitinol U-Clip device (Coalescent Surgical, Inc, Sunnyvale, Calif) was used in 13 consecutive calves (63-118 kg). In each animal, the device was (1) used to create an anastomosis of the right internal thoracic artery to a coronary artery with the heart beating and (2) compared to polypropylene suture when used to repair two carotid arteriotomies. Intraoperative, 1-week, 8-week, and 26-week postoperative angiograms and detailed histopathologic examinations were used to evaluate anastomotic patency and healing characteristics. RESULTS: The nitinol U-Clip device successfully created right internal thoracic artery-coronary artery anastomoses and repaired carotid arteriotomy sites in 13 consecutive calves. The clip was precisely placed by means of the integrated suture and needle in a fashion similar to that used for conventional suture. The clip met design specifications by reliable release and automatic closure, thereby eliminating knot tying and assisted suture management. At the time of harvest, angiography showed widely patent coronary anastomoses (FitzGibbon grade A criteria, n = 13) and carotid arteriotomy repair sites (n = 13). Histopathologic evaluation confirmed normal healing with smooth circumferential neointimal resurfacing at the anastomotic and repair sites. CONCLUSIONS: The nitinol U-Clip design and function was validated in the formation of bovine coronary anastomoses on the beating bovine heart with excellent graft patency and healing characteristics. The nitinol U-Clip device tests favorably when compared with conventional sutures in carotid artery repair.     

Unconventional vessel wall apposition in off-pump porcine coronary artery bypass grafting: low versus high graft flow

OBJECTIVE: Facilitated coronary anastomosis techniques may involve unconventional vessel wall apposition in contrast to standard intima-intima apposition. We assessed the patency, anastomotic thrombus formation, and intimal hyperplasia of unconventional intima-adventitia apposition versus conventional suturing techniques in beating heart coronary bypass grafting under low versus high graft flow conditions. METHODS: The intima-adventitia (n = 28) and conventional anastomoses (n = 28) were evaluated intraoperatively (n = 56), at 4 hours (n = 20), and at 5 weeks (n = 36) in a new off-pump low-flow (n = 28) and high-flow (n = 28) porcine bypass model (< or = 15 mL/min and about 60 mL/min, respectively). The anastomoses were assigned to the animals by means of randomized stratification and examined by means of flow measurements, angiography, and histology. RESULTS: Mean graft flows in intima-adventitia and in conventional anastomoses were similar (P =.709). All but 1 of 56 anastomoses (low flow conventional) were fully patent at the time of death. At 4 hours, only small platelet depositions were found at the exposed media and adventitia in the unconventional anastomoses. At 5 weeks, little streamlining intimal hyperplasia was found, which was comparable between the anastomoses (P =.600). CONCLUSIONS: In low-flow conditions (< or = 15 mL/min) unconventional intima-adventitia apposition was not detrimental to the internal thoracic-coronary artery anastomosis in the pig. This finding may expand design strategies of facilitated coronary artery bypass anastomosis techniques.     

Magnetic vascular coupling for distal anastomosis in coronary artery bypass grafting: a multicenter trial

OBJECTIVE: The hand-sewn anastomosis is the "gold standard" for performing coronary artery bypass grafts. However, performing a hand-sewn anastomosis is more demanding and time-consuming when used in less invasive approaches such as small access, totally endoscopic or beating heart surgery. In conjunction with attempts to reduce the surgical trauma of coronary artery bypass grafts by using these less invasive approaches, alternative methods for constructing distal anastomoses should be explored. These data report on predischarge angiographic findings and 30-day clinical follow up of patients who have received a new distal anastomotic device. METHODS: In a multicenter trial, 32 patients (mean age: 65 +/- 9 years; 85% men) requiring multivessel coronary artery bypass surgery had 1 of the anastomoses performed using a novel anastomotic technology. The Magnetic Vascular Positioner System was used in 1 of the bypass grafts and the other bypasses were completed by conventional hand-sewn technique. The Magnetic Vascular Positioner System consists of 4 magnetic, gold-plated implants and 2 delivery devices that facilitate the creation of a functional end-to-side anastomosis. A predischarge angiogram was performed to evaluate graft patency. RESULTS: There were no device-related major adverse events. The application of the Magnetic Vascular Positioner device was successful in 32 of 41 cases (78%). Nine patients were intended for treatment but did not receive the Magnetic Vascular Positioner System. In 5 of the cases the coronary artery was too small; 1 case had a posterior wall plaque in the target artery; and 3 patients had a nonhemostatic anastomosis after coupling of the port and were subsequently converted to hand-sewn anastomoses. The median total Magnetic Vascular Positioner anastomotic time was 137 seconds with a range from 65 to 370 seconds. Overall patency rate of the Magnetic Vascular Positioner anastomosis was 93.5% versus 91.7% (P = not significant) in hand-sewn grafts. One patient (3.1%) died due to low cardiac output but had patent grafts at autopsy. One myocardial infarction (3.1%) occurred the day after a percutaneous transluminal coronary angioplasty of a hand-sewn graft. One prolonged mechanical ventilation (3.1%) was required because of pneumonia and adult respiratory distress syndrome. CONCLUSIONS: Magnetic vascular coupling in coronary surgery is safe and effective and has acceptable early patency rates. This new technique may facilitate beating heart and minimally invasive coronary artery bypass grafts.     

Evaluation of a new device for quick sutureless coronary artery anastomosis in surviving sheep.

OBJECTIVE: A new device for performing quick sutureless vascular anastomosis by means of stent technology has recently been developed by Jomed International, Helsingborg, Sweden. The efficacy of this GraftConnector was studied in a sheep model. METHODS: In adult sheep, a left anterior thoracotomy under the fourth rib extended across the sternum gave good access to the left anterior descending branch (LAD) and the right internal mammary artery (RIMA). On beating hearts, the GraftConnector group had the RIMA connected to the LAD by means of the new device, while the control animals had the same anastomoses sutured with continuous 7-0 polypropylene sutures. The time for completing the anastomosis (ischemic time) was recorded and the blood flow in the RIMA was recorded with the proximal LAD open and closed, respectively. An intra-operative fluoroscopy with contrast injection directly into the graft was done. Finally the proximal LAD was ligated. The surviving animals are to be followed up. RESULTS: Seven (46%) of the 15 animals operated on with the traditional suturing technique and seven (63%) of the 11 GraftConnector sheep survived the procedures and are to be followed up. The 11 anastomoses done with the GraftConnector were completed in 2.41+/-0.2 min, and the 14 anastomoses sutured with continuous suture were completed in 6.93+/-0.419 min (P<0.0001). The RIMA blood-flows in the two groups were comparable and are presented. All the surviving animals had open anastomoses at fluoroscopy. CONCLUSIONS: Quick coronary artery anastomoses without suturing on beating hearts can be completed with the new GraftConnector. The GraftConnector creates reproducible anastomoses in much less time than suturing, the per-operative mortality in the GraftConnector Group was accordingly lower. Long-time follow-up of the patency in surviving animals is pending. The presented device may ultimately permit quick anastomoses endoscopically.     

Factors affecting patency of internal thoracic artery graft: clinical and angiographic study in 1434 symptomatic patients operated between 1982 and 2002.

OBJECTIVE: The purpose is to define factors influencing long-term patency of the internal thoracic artery (ITA) to optimize the operative strategy. METHODS: 1482 left internal thoracic artery (LITA) and 636 right internal thoracic artery (RITA) symptom-directed angiograms were studied in 1434 patients. Data were prospectively collected from patients who had primary coronary artery bypass surgery during the period 1982-2002. The mean age of patients was 59 years; 85% were male. The mean period from operation to re-angiogram was 80 months. LITA was grafted to left anterior descending coronary artery (LAD) in 82% of cases, RITA to right coronary artery (RCA) in 40% and circumflex artery in 35% of cases. Graft failure was defined as > or =80% stenosis. RESULTS: 96.3% of LITA and 88.1% of RITA grafts were patent. No patient variables were significantly associated with graft patency (age, gender, diabetes, hypertension, LVEF, NYHA, AMI). Target coronary artery was associated with patency of both LITA and RITA grafts with maximum patency when grafted to LAD (P = 0.02) RITA had the worst patency to RCA, patency for the left system was identical to LITA. Proximal anastomosis to aorta (free RITA) had significantly better patency when compared with in situ RITA to RCA system (P = 0.005) while similar patency when grafted to left system. ITA diameter and target artery diameter were not associated with graft patency. Recent operations had better RITA patency (P = 0.03). The interval from operation to angiogram was not associated with ITA patency (96% patency for LITA and 88% patency for RITA, remained stable when studied at <1, 1-4, 5-9, 10-14 and >15 years). CONCLUSIONS: Even in a patient cohort that had adverse symptoms, excellent LITA and RITA patency was achieved which almost remained constant through all time intervals studied.