Clinical experience with devices for facilitated anastomoses in coronary artery bypass surgery

Prospective Evaluation of Patency and Early Experience Utilizing an Automated Distal Anastomosis Device (C-Port)

Background

In November 2005, a new automated distal anastomotic device (C-Port) for coronary artery bypass grafting (CABG) was cleared by the FDA for use in the United States. This study represents a prospective evaluation of our early experience using the device with graft patency assessment determined by 64 slice multidetector row computed tomography angiography (64CT).

Materials and Methods

Patients undergoing coronary artery bypass were evaluated preoperatively by cine angiography for possible use of the C-Port system. A final decision for its use was made clinically at operation based on target vessel and vein graft specifications. Patency of the grafts was evaluated at 1 to 7 months (average 91 days) by 64CT with IRB approval and signed informed consent.

Results

The C-Port device was used to form 69 distal anastomoses in 50 patients (46 CABG were performed off pump). There were eight misfires with no adverse effects for an immediate success rate of 88.4%. Thirty-five of 41 patients were available postoperatively for evaluation by 64CT (85.4% follow-up). There was one postoperative death. Seventeen sequential anastomoses were excluded because of inability to reliably evaluate patency by 64CT. Four 64CT scans were uninterpretable. For the remaining 31 patients, 64CT scans were used to evaluate for graft patency. The overall patency rate for all anastomoses was 94.5% (86/91) with selected patency for internal mammary artery of 100% (28/28), for C-Port connectors of 93.3% (42/45), and for hand-sewn venous end-to-side anastomosis of 88.9% (16/18). The difference in patency between C-Port anastomoses and hand sewn was not statistically significant (P = 0.62).

Conclusions

The C-Port system provides reliable and reproducible compliant automated distal venous anastomoses, which results in acceptable patency at intermediate follow-up. With proper training, the learning curve for using this connector system is relatively short and the need to abandon the procedure is low. 64CT is an excellent noninvasive method for cardiac surgeons and their institutions to accurately evaluate their actual surgical results.

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)

The vascular connector, design of a new device for sutureless vascular anastomosis

BACKGROUND

In recent years, several methods and new techniques have been studied and proposed for establishment of sutureless vascular anastomoses, streaming use of sutureless vascular surgery in the future.

PRESENTATION OF THE HYPOTHESIS

The new vascular connector (NVC) is a hypothetical design of a vascular device, proposed for creation and maintenance of sutureless vascular anastomosis. Implication of NVC would introduce a new device and technique in establishment of sutureless vascular anastomosis in which surgical approach is minimized and so post-operation disorders. It would eliminate need for suture; shorten clampage and operation time, consequently reducing stress for both, the surgeon and the patient. It enables the creation of vascular anastomosis fast, simple, safe, reliable, with satisfactory patency and stability of anastomosis.

TESTING THE HYPOTHESIS

Efficacy of NVC needs to be evaluated in further studies, in order to be confirmed for clinical use. The effectiveness of NVC should be verified firstly in vitro and in vivo tests; and by animal experiments. The likelihood of its negative influence in thrombogenicity should be well evaluated.

IMPLICATIONS OF THE HYPOTHESIS

Implication of the new vascular connector (NVC) would be of interest to both patients and the surgeon due to the following main achievements: 1) enables the creation of vascular anastomosis fast and simple, 2) significant shortening of clampage time of blood vessels and operation time-this assumption would be followed by reduced risk of operative and post-operative complications and length of hospital stay or admission to Intensive care unit, 3) safe and reliable, 4) compatible with any blood vessel and standard vascular graft, 5) using the NVC we will reduce in minimum need for replaced blood volume, 6) reduces the cost of treatment. It is anticipated that the NVC would provide shorter operation time and least operative and post-operative complications in creation of sutureless vascular anastomosis.

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.

Neointimal Hyperplasia Associated with the Use of U-Clip

The U-Clip (Coalescent Surgical, Sunnydale, CA USA) allows the surgeon to create an interrupted anastomosis in the same amount of time that is required for a continuous anastomosis with the elimination of knotting. Its use is indicated especially in minimally invasive surgery. We describe a case of a patient in which the proximal anastomosis was performed by interrupted suture with Coalescent U-Clip anastomotic device. Six months later, he presented with stenosis of the anastomosis, and intravascular ultrasound showed anastomotic neointimal hyperplasia.

A stand-up collar around the saphenous vein graft

We present a technique of a stand-up collar around the saphenous vein graft using a pedicled fat pad flap. This procedure is simple and effective to avoid kinking in a graft that was proximally anastomosed with an automatic device and to maintain the graft in its natural position.

A multicenter prospective randomized trial of a second-generation anastomotic device in coronary artery bypass surgery

OBJECTIVE

Our objective was to perform a prospective randomized trial to evaluate the clinical and angiographic outcomes of a second-generation anastomotic device used for saphenous vein grafts.

METHODS

Patients undergoing nonemergency isolated coronary artery bypass grafting at 3 centers from August 2003 to December 2004 with at least 2 saphenous vein grafts were included. The proximal anastomoses were randomized, within each patient, to be constructed by the connector or by suture. One-year graft patency was evaluated by coronary angiography, magnetic resonance imaging, or computed tomography and analyzed on an intent-to-treat basis.

RESULTS

A total of 151 patients (65 +/- 9 years, 87% male) who met inclusion/exclusion criteria were enrolled in the study and were analyzed. A total of 489 grafts were constructed (3.2 +/- 0.5 grafts per patient), including 327 vein grafts randomized to the connector (n = 162) or suture (n = 165). In 162 connector grafts, 151 devices were successfully implanted. Technical issues required explantation of 11 devices intraoperatively. Patency was evaluated in 120 (81%) patients with 260 study grafts. Seventy-four patients with 161 grafts were evaluated by coronary angiography, 31 patients with 69 grafts by magnetic resonance imaging, and 15 patients with 30 grafts by computed tomography. The 1-year patency rate for study grafts constructed with the anastomotic connector was 92.2% (118/128) and for hand-sutured grafts, 91.7% (121/132).

CONCLUSIONS

This prospective multicenter randomized controlled trial demonstrated good in-hospital and late clinical outcomes and excellent 1-year patency for vein grafts anastomosed both by the St Jude Medical second-generation aortic connector system and by hand. The patency of the connector grafts did not differ from that of the hand-sutured grafts.

Hemodynamic Performance of a Sutureless Anastomosis Device (the Graft Connector): A Numerical Study

Sutureless anastomosis devices have been developed to facilitate arterial bypass surgery on the beating heart. However, these devices can significantly alter the hemodynamics at the end-to-side anastomosis and in the host artery, leading to the formation of thrombus or/and intimal hyperplasia (IH). In this study, a numerical analysis was performed on the hemodynamic performance of the Graft Connector (GC), a sutureless anastomosis device, under pulsatile flow conditions. The results showed that blood flow was severely disturbed in the GC model with the formation of vortices and flow stagnation at the bed and the toe, and distal to each of the stent struts, which led to low wall shear stresses and high oscillating shear indices in these regions. This may cause severe IH in the host artery and compromise the performance of the device. Based on the numerical study, suggestions were proposed for the design of the GC to improve its performance.

Initial clinical experience with a new end graft holder for anastomosis in coronary surgery

OBJECTIVE

We assessed the feasibility and effectiveness of a novel end graft holder for coronary artery bypass grafting (CABG) and evaluated anastomotic patency and early clinical results.

METHODS

The end graft holder was applied to 45 consecutive patients. Operative characteristics were off-pump CABG in 22.2%, emergency in 28.9%, and concomitant cardiac surgery in 13.3%.

RESULTS

The device was used safely without graft injury or inadequate gripping on grafts. Postoperative angiography showed that the patency rate of distal anastomosis was 96.7% (arterial, 100%; venous, 94%). All proximal aortic and composite graft anastomoses were patent without stenosis. The rate of 30-day major adverse cardiac and cerebrovascular events was 13.3% (operative deaths, 3; repeated CABG, 1; percutaneous coronary arterial intervention, 1; and cerebral infarction, 1). None of the elective patients died during hospitalization.

CONCLUSION

Our initial clinical experience demonstrated that the new end graft holder was safe, reliable, and effective during CABG. The excellent fixation and visualization of the graft with the device might be particularly beneficial for off-pump CABG or for teaching trainees.

New device for saphenous vein-to-aorta proximal anastomosis without side-clamping

Background

Side clamping to perform saphenous vein-to-aorta proximal anastomosis is a well known cause of cerebral embolization during coronary bypass surgery. Automatic and manual devices have been introduced to avoid aortic clamping and facilitate proximal anastomosis but the manual ones only allow the traditional hand-sewing running suture. Nevertheless, they are not easy to use and very expensive to buy.

Methods

We developed a simple object that helps to perform a manual proximal anastomosis without the need to clamp the side of the aorta. This device is a steel bar which blocks the aortic hole and simultaneously it provides a slit to receive the needle. Through the slit comes out a thin, sharp, straight, but also well directed and predictable jet of blood which could be easily controlled during the suture.

Results

The function of the object is quite different from other devices. Nothing is deployed in the aorta. The object is only placed on the aorta with the small appendage slipped into the hole. The main advantage of the device is that while manipulation of the aorta is avoided no foreign bodies are incorporated in the suture and – most importantly – the aortic intima is not touched at all. The main drawback of the device is the blood jet coming from the slit so that the blood pressure has to be lowered by vasodilators during the anastomosis. Moreover, the suture has to change direction and the needle has to enter the aortic wall first to slip out through the slit.

Conclusion

The object was named "Slit Device" and is not a routine instrument. It would be only an alternative to other anastomotic devices with the same surgical indications. In the case of ascending aortic disease and saphenous vein grafting, the Slit Device avoids aortic clamping thereby preventing atheroembolism and also avoiding the need for hypothermic circulatory arrest in patients with unclampable aorta.

Patency outcomes of aortic connectors

OBJECTIVE

: Controlled outcome analysis of mechanical aortic connectors for proximal saphenous vein bypass graft anastomosis is lacking. We report the clinical and angiographic outcome of patients receiving the Symmetry aortic connector (St. Jude Medical, Inc St. Paul, MN, US) within a multicenter, prospective, randomized study.

METHODS

: Twenty-five patients at 3 study sites received aortic connectors at the time of coronary artery bypass surgery. Protocol-defined angiographic follow-up was completed in 19 of 25 patients (76%) at time-points up to 14 months postoperatively; 32 connector anastomoses were evaluated in these 19 patients. Beating heart surgery was performed in 17 patients, and 2 were performed with cardiopulmonary bypass. Age was 69.7 ± 8.1 year; all patients were males.

RESULTS

: The connector anastomosis patency rate was 15.6% (5/32). There were no deaths during the follow-up period. Four patients (21%) suffered myocardial infarction and 2 additional patients (10.5%) required percutaneous coronary interventions; one of who required 3 percutaneous coronary interventions, the other received one percutaneous coronary intervention.

CONCLUSIONS

: In this nonrandomized cohort of patients, occlusion rate with Symmetry connectors was significantly greater than anticipated. Patients who have received these connectors during coronary artery bypass surgery may require closer follow-up and evaluation. While the manufacturer has stopped producing this device, there has been no recall of the product, clinical support remains ongoing, and next generation connectors have now been marketed. Consideration should be given to discontinuation of the clinical use of Symmetry connectors.

Six-Month Angiographic Follow-Up of the PAS-Port II Clinical Trial

BACKGROUND

The PAS-Port device (Cardica, Redwood City, CA) allows the rapid deployment of a clampless proximal anastomosis between a vein graft and the aorta.

METHODS

Fifty-four patients awaiting elective coronary artery bypass graft surgery were enrolled. Outcome variables were intraoperative device performance, early and 6- month angiographic graft patency, and 12-month clinical follow-up.

RESULTS

Sixty-three PAS-Port devices were deployed in 54 patients. Two deployments were unsuccessful. There were no reoperations for bleeding. Two patients died of causes unrelated to the device. Patency evaluation at discharge was performed by angiogram on 49 implants and computed tomography in 2 implants (86% follow-up). At discharge, all evaluated grafts were patent (100%) and rated Fitzgibbon A. At 6-month follow-up, there was no additional mortality; 47 implants (88% follow-up) were evaluated by angiography (Fitzgibbon O [n = 1], Fitzgibbon B [n = 1], and Fitzgibbon A [n = 45]) and 5 by computed tomography. All grafts but 1 were patent (98.1%). At 12 months, 2 additional patients died of causes unrelated to the PAS-Port implant. Forty-six of 50 alive patients (95.8%) were followed up without any reports of device-related major adverse cardiac events.

CONCLUSIONS

Discharge (100%) and 6-month patency (98%) are excellent; patency and 12 months' clinical follow-up compares favorably with data from historical hand-sewn controls. The PAS-Port system safely allows the clampless creation of a proximal anastomosis.

Symmetry™ Aortic Connector Devices and Acute Renal Injury: A Comparison of Renal Dysfunction After Three Different Aortocoronary Bypass Surgery Techniques

Although the pathogenesis of acute renal injury after cardiac surgery is multifactorial, atherosclerosis of the ascending aorta and embolic burden are strong independent predictors. Use of the Symmetry aortic connector device (ACD) for proximal anastomosis of coronary grafts may reduce ascending aortic atheroembolism. Therefore, we tested the hypothesis that off-pump coronary artery bypass (OPCAB) surgery performed using an ACD is associated with less postoperative renal dysfunction compared with conventional OPCAB or on-pump coronary artery bypass graft (CABG) surgery. Three-thousand-three-hundred consecutive patients undergoing non-emergent aortocoronary bypass surgery were retrospectively divided into three groups by surgical procedure; Group A: OPCAB with ACD (n = 124), Group B: standard OPCAB (n = 313), Group C: on-pump CABG (n = 2863). Postoperative peak fractional change in creatinine compared with baseline was used as a measure of renal outcome. Multivariable analysis did not identify ACD use as an independent predictor of postoperative peak fractional change in creatinine (P = 0.71), although the relationships of several known renal risk factors with postoperative peak fractional change in creatinine were confirmed. We could not find evidence that OPCAB surgery using ACDs reduces acute renal injury compared with standard OPCAB or CABG surgery.

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.

Early clinical results of St. Jude Medical Symmetry aortic connector

An automated anastomosis device named St. Jude Medical symmetry aortic connector has been used worldwide for off-pump coronary artery bypass grafting. However, early graft obstruction was recently reported, and its predictors should be clarified. From April 2002 to March 2004, 38 patients in our institution underwent off-pump coronary artery bypass grafting using the St. Jude Medical Symmetry aortic connector for saphenous vein graft (SVG) procedures; measurement of intraoperative graft flow and postoperative coronary angiography was performed. Early SVG events occurred in 9 (24%) patients: 8 occlusion cases and 1 case of stenosis. Predictors of early SVG events were assessed from a comparative study. Univariate logistic regression identified hyperlipidemia as the only significant predictor of early SVG events (P = 0.02, odds ratio 7.78). Lower SVG flow rate and poor ejection fraction did not show statistical significance (P = 0.09, odds ratio 1.09 and P = 0.09, odds ratio 0.96). The SVG event rate was much higher for the left circumflex branch compared with other locations (31% vs. 9%, P = 0.03) and decreased with increasing aortic connector size (small, 32%; median, 14%; large, 0%). Multivariate analysis did not identify a predictor of SVG events. The aortic connector is associated with a high incidence of early SVG events. Patients should be cautiously selected and the procedure should not be used for left anterior descending coronary artery or culprit lesions.

Clinical and angiographic results after mechanical connection for distal anastomosis in coronary surgery

BACKGROUND

Sutureless anastomotic devices are of increasing interest in cardiovascular surgery. We investigated the stainless steel clip system of St Jude Medical/Anastomotic Technology Group (Maple Grove, Minn) to connect saphenous vein grafts with coronary arteries.

METHODS

Forty-five patients were enrolled in this feasibility study performed on patients who had on-pump coronary artery bypass grafting, but 32 patients only received 1 distal anastomosis with this investigational device (2.5 mm [n = 14] and 2.0 mm [n = 18]). Thirteen were excluded because target vessels were too small, calcified, or tortuous. The system consists of an expandable clip mounted on a balloon catheter; delivery is obtained during balloon inflation. The main differences between the 2.5-mm and 2.0-mm devices are different loading and deployment in smaller coronary arteries for the 2.0-mm device.

RESULTS

A connecting device was deployed on the right coronary artery in 14 patients, the posterior descending branch in 12 patients, the obtuse marginal in 5 patients, and the posterolateral branch in 1 patient. Perfect hemostasis of the sutureless connector anastomosis was obtained in 28 patients. Three connectors were removed because of minor leakage at the connection site, and 1 connector was removed because of mismanipulation after successful deployment. Hand-sewn anastomosis was performed at the same arteriotomy site. Intraoperative flow was assessed by the transit time method and averaged 71 +/- 24 mL/min. One patient died of neurologic injury; the connector was patent at autopsy. One patient had a perioperative myocardial infarction. There was no adverse cardiac event in the remaining patients. All patients underwent clinical follow-up after 6 and 12 months and 35 angiograms were available in 21 patients: after 3 and 6 months, 17 anastomoses were patent and the saphenous vein graft was occluded in 4 patients.

CONCLUSIONS

The coronary connector system from St Jude Medical/Anastomotic Technology Group allows consistently uniform sutureless connection between the saphenous vein graft and coronary artery. Loading and deployment require careful training. This technology is under constant development and may give a significant boost to less invasive coronary revascularization techniques.