Clinical, angiographic, and interventional follow-up of patients with aortic-saphenous vein graft connectors

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.

Avoidance of aortic side-clamping for proximal bypass anastomoses: better short-term outcome?

OBJECTIVES

The benefit of off-pump coronary artery bypass (OPCAB) surgery may be reduced by strokes caused by microemboli produced after aortic side-clamping for proximal bypass anastomoses. The Heartstring device allows constructing proximal bypass anastomoses without side-clamping of the aorta.

METHODS

This retrospective study describes 260 consecutive patients who underwent OPCAB surgery; 442 proximal anastomoses were performed with the Heartstring device in this series. Ten percent of the patients were randomly sampled before discharge to undergo a coronary angiogram for assessment of graft patency.

RESULTS

Intraoperative Doppler measurements confirmed regular bypass function. Early mortality occurred in 4 patients (1.5%), and stroke occurred in 2 patients (0.8%). Device-related bleeding was negligible, and there were no cases of aortic dissection. Perioperative ischemia occurred in 8 patients (3.1%). Predischarge coronary angiography evaluations in 25 of the patients (of 260) showed that all 42 Heartstring-assisted anastomoses (of 442) were patent.

CONCLUSIONS

Clampless performance of proximal bypass anastomoses combined with OPCAB is associated with a very low incidence of stroke complications. Short-term follow-up has shown excellent results regarding bypass patency and other adverse events. Prospective randomized trials are required to confirm the advantage of this technique.

Sutureless proximal anastomosis using the PAS-Port system: six-month patency and five-year follow-up in "all-comers"

BACKGROUND

The PAS-Port system (Cardica, Inc, Redwood City, CA) was used routinely for patients undergoing coronary surgery with at least one venous graft. Graft patency and clinical results were evaluated, respectively, at 6 months and 5 years after surgery.

METHODS

A total of 100 patients (82 males, 18 females; mean age 68.9 ± 12 years) underwent coronary bypass surgery with at least one PAS-Port anastomosis (total number of PAS-Port implants: n = 117). At 6 months after surgery all patients were followed up clinically and 86 patients with 101 PAS-Port implants underwent either a multidetector computed tomographic scan or coronary angiography. Actuarial freedom from MACCE (major adverse cardiac and cerebrovascular events) was assessed at 5 years after surgery.

RESULTS

Six-month PAS-Port patency was 88%. The inner diameter of the graft at the implant site (measured in 26 patients) did not reveal any pathologic narrowing (mean inner diameter 3.1 ± 0.6 mm). At 5 years, freedom from overall MACCE was 79% ± 5% and freedom from PAS-Port target vessel revascularization was 94% ± 6%.

CONCLUSIONS

The routine use of PAS-Port was associated with good vein graft patency at 6 months and a low incidence of MACCE at 5 years after surgery. No evidence of implant-related graft stenosis was detected.

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.

Nitinol in Magnetic Resonance Imaging

Surgical and interventional instruments as well as implants can cause significant magnetic resonance image (MRI) artifacts. The artifacts can be used to visualize instruments, cannulae, guide wires, catheters during interventional MRI and Nitinol devices have proven to be useful for MRI procedures. Diagnostic imaging is often compromised in the area of an implant. Complete vanishing of signals occurs in close proximity or inside implants. The paper presents a fundamental evaluation of MRI artifact of Nitinol devices such as Stents, Vena Cava Filter, heart defect closure devices, cannulae, guide wire, localizer, anastomosis device, etc. in a 1.0 Tesla magnetic field. The American Society for Testing Materials (ASTM) recommendations for selection of sequences and test setup were used but the results of this paper are not sufficient for FDA approval.

Spyder Aortic Connector System in Off-Pump Coronary Artery Bypass Surgery

PURPOSE

The Spyder aortic connector (Medtronic, Minneapolis, MN) is a new, promising connector device and its safety and efficacy have been evaluated in this study.

DESCRIPTION

Twenty-two patients were randomized to proximal vein graft anastomosis with the Spyder aortic connector (Medtronic) or hand-sewn technique.

EVALUATION

Twenty patients underwent multi-detector computed tomographic scans of the chest 6 months after surgery to evaluate vein graft patency. We have failed to successfully deploy three Spyder connector devices. Thus in this study we have evaluated the graft patency of 19 hand-sewn grafts and of 19 vein grafts anastomosed with the Spyder anastomotic device. Three vein grafts whose proximal anastomosis was accomplished with the Spyder anastomotic connector were occluded and all hand-sewn vein grafts were patent (16% vs 0%; p = 0.23). Stenosis of the proximal anastomosis was observed in seven vein grafts (37%), accomplished with the Spyder anastomotic connector, and in one (5%) hand-sewn vein graft (p = 0.042).

CONCLUSIONS

The results of this study suggest that the use of the Spyder aortic connector device is associated with suboptimal 6-month graft patency.

Forty-one-month follow-up of the Symmetry aortic connector system for proximal venous anastomosis

OBJECTIVE

Results of short- and midterm follow-up studies of the patency rate of the Symmetry aortic connector systems (St Jude Medical, Inc, Minneapolis, Minn) are controversial. Long-term follow-up studies are still lacking (so far, the longest mean follow-up period was 19 months). The aim of our study was (1) to evaluate the patency rate of this device over a longer time-period and (2) to analyze risk factors for graft occlusion.

METHODS

Between November 2000 and July 2003, 76 Symmetry aortic connector systems were implanted in 42 patients. At follow-up, 24 patients with 44 mechanical connectors were studied with 64-slice cardiac computed tomography. Eight patients had died previously, 6 patients refused to undergo a computed tomographic scan, and 4 patients had to be excluded because of impaired renal function.

RESULTS

From a total of 44 mechanical connectors studied, 24 (55%) were occluded, 20 (45%; confidence intervals 31%-61%) were patent, and 7 of these grafts showed stenosis in the area of the connector. Mean follow-up was 41 +/- 10 months (18-52 months). Sex, age, left main stenosis, hyperlipidemia, hypertension, renal failure, target vessel, stenosis of the target vessel, diameter of the target vessel, type of surgical intervention, diabetes, ejection fraction, postoperative anticoagulation regimen, and the connector size showed no significant influence on the bypass graft patency (P > .05). The bypass graft flow was recognized to be the only risk factor for bypass graft occlusion (P = .0256).

CONCLUSION

Midterm follow-up data show a high number of occluded Symmetry aortic connector system vein grafts. On the basis of these observations, the use of the connector was abandoned at our institution.

Mid-term follow up of patients using the St. Jude Medical Aortic Connector System for proximal vein graft in CABG

The aortic connector system may reduce stroke during proximal venous anastomosis. However, the overall anastomotic patency rate has been generally reported to be low. From October 2002 to March 2004, 68 patients who received proximal anastomosis using the St. Jude Aortic Connector System were included in the study. There were 47 men and 21 women and their mean age was 65.68+/-6.68 yr old (52 to 85 yr). Grafts were evaluated by coronary angiography or multi-slice 16 channel 3-D CT at 6 days and at 6 months postoperatively. In the immediate postoperative period, no stenosis was observed by either angiography (n=22) or 3D CT (n=46). At 6-month postoperatively, we performed either angiography (n=7) or 3-D CT (n=52). Of these patients, 5 patients showed graft stenosis in the midportion, and 3 in the ostium. There were no stroke. Simple, and effective proximal anastomosis with good protection from cerebrovascular accident was achieved especially when calcification or atheromatous plaque was observed at the ascending aorta in the operation room. However, our mid term patency results raise concerns related to venous graft stenosis in the midportion. Therefore, longer follow up is recommended.

Prospective, Randomized Study on the Use of the Cardica PAS-Port Aortic Connector System in Off-Pump Coronary Artery Bypass Surgery

BACKGROUND

The use of aortic connector devices for proximal vein graft anastomosis has been shown to be associated with a relevant rate of early graft complications. Cardica PAS-Port is a new aortic connector whose preliminary clinical results seem promising. The safety and efficacy of this aortic connector device have been evaluated in this prospective, randomized study.

MATERIAL AND METHODS

Twenty-four patients were randomized to receive proximal aorta-vein graft anastomosis with either the Cardica PAS-port aortic connector or by the hand-sewn technique. Twenty-three patients underwent multidetector computed tomographic scan (MDCT) of the chest 6 months after surgery to evaluate graft patency.

RESULTS

All aortic connector devices (18) were successfully deployed and 31 proximal anastomoses were performed by the hand-sewn technique. MDCT showed that 6-month freedom from vein graft complication was 22.2% in the PAS-Port group and 58.1% in the hand-sewn group (P = .04). Four vein grafts (22.2%) anastomosed with the PAS-Port and 2 hand-sewn vein grafts (6.5%) were occluded (P = .10). The use of the PAS-Port aortic connector was also predictive of any vein graft complication when adjusted for vein graft flow (P = .01; OR 8.64, 95% CI 1.66-45.00) and for peripheral resistance units (P = .02; OR 6.14, 95% CI 1.33-28.43).

CONCLUSIONS

The results of this prematurely stopped, prospective, randomized study suggest that the use of PAS-Port aortic connector device is associated with a higher rate of early vein graft complications than the hand-sewn technique.

Treatment of ischemic stroke complicating cardiac catheterization with systemic thrombolytic therapy

Ischemic stroke is a rare but serious complication of cardiac catheterization. We report a case in which systemic thrombolytic therapy was successfully utilized in treating a patient with a cerebellar stroke, leading to obtundation during elective cardiac catheterization. Underlying bilateral vertebrobasilar disease with thrombotic embolization to the basilar artery was postulated to be the pathophysiological basis for the stroke and subsequent success of thrombolytic treatment in this patient. As the consequences of this rare complication are severe, systemic thrombolytic therapy should be considered for patients suffering an acute ischemic stroke during cardiac catheterization or percutaneous coronary intervention.

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.

Clampless Anastomosis: Novel Device for Clampless Proximal Vein Anastomosis in OPCAB Surgery--The Initial Spyder Experience

The Spyder is a novel device that enables the attachment of a vein to the aorta by compliant, interrupted anastomosis; this minimizes aortic manipulation during off pump-coronary artery bypass (OPCAB) surgery. Its use may reduce transcranial Doppler signals recorded during CABG. We performed 250 anastomoses in 160 OPCAB cases in many centers and recorded efficiency and efficacy data. There were no adverse events noted during the operative period. In a subset of patients in one center, flow (n = 48) and transcranial Doppler signals (n = 22) were measured. We found the device to be a useful adjunct for minimally invasive CABG surgery.

Early and midterm patency of the proximal anastomoses of saphenous vein grafts made with a Symmetry Aortic Connector System

OBJECTIVE

The purpose of this study was to investigate (1) the early and midterm patency rates in saphenous vein grafts that were anastomosed with the Symmetry Aortic Connector System (St Jude Medical, Inc, St Paul, Minn) and (2) risk factors for graft occlusion.

METHODS

Thirty-one patients underwent off-pump coronary artery bypass grafting for proximal saphenous vein graft anastomoses with the aortic connector system. Intraoperative graft flow was studied with transit time flowmetry, and angiography was performed before discharge in 29 cases. Midterm (at least 1 year after the operation) saphenous vein graft patency was assessed by coronary angiography or 3-dimensional coronary computed tomography in 27 cases.

RESULTS

Postoperative angiography demonstrated a 100% patency rate and no significant stenosis at the connector-anastomosed sites. The 1-year patency rate of the saphenous vein grafts with the aortic connector system was 92.6%, with 2 cases of saphenous vein graft occlusion. Both of these cases had low graft flow and poor left ventricular function documented during the operation.

CONCLUSION

Once surgical errors had been ruled out, the 1-year patency rate of proximal saphenous vein grafts anastomosed with the aortic connector system was favorable. Poor left ventricular function and low graft flow during the operation were risk factors for midterm graft occlusion. Selection of the target vessel and its runoff may also be an important determinant of long-term patency.

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.

Coronary Artery Bypass Grafts: Assessment with Multidetector CT in the Early and Late Postoperative Settings

Coronary artery bypass graft (CABG) surgery is the standard of care in the treatment of advanced coronary artery disease. It is well known that the long-term clinical outcome after myocardial revascularization depends on the patency of the bypass grafts. In the past, invasive coronary angiography was used to assess the status of the grafts and check for graft occlusion. Recently, computed tomography (CT), particularly multidetector CT with electrocardiographic gating, has emerged as an important diagnostic tool for evaluation of CABGs in both the early (< or =1 month) and late (>1 month) postoperative settings. A variety of postoperative complications may manifest as dyspnea and chest pain, thereby mimicking recurrent angina secondary to graft occlusion. Owing to its improved spatial resolution compared with that of earlier-generation CT scanners and its ability to produce three-dimensional and multiplanar images, multidetector CT has assumed an integral role in characterization of graft patency while allowing investigation of alternative postoperative complications. In addition, the expanded capabilities of volumetric imaging may provide valuable information in preoperative planning for repeat CABG surgery.

Five year clinical effect of coronary stenting and coronary artery bypass grafting in renal insufficient patients with multivessel coronary artery disease: insights from ARTS trial

AIMS

To compare coronary stent implantation and bypass surgery for multivessel coronary disease in patients with renal insufficiency.

METHODS AND RESULTS

In the ARTS trial, 142 moderate renal insufficient patients (Ccr<60 mL/min) with multivessel coronary disease were randomly assigned to stent implantation (n=69) or CABG (n=73). At 5 years, there was no significant difference between the two groups in terms of mortality (14.5% in the stent group vs. 12.3% in the CABG group, P=0.81), or combined endpoint of death, cerebrovascular accident (CVA), or myocardial infarction (MI) (30.4% in the stent group vs. 23.3% in the CABG group, P=0.35). Among patients who survived without CVA or MI, 18.8% in the stent group underwent a second revascularization procedure when compared with 8.2% in the surgery group (P=0.08). The event-free survival at 5 years was 50.7% in the stent group and 68.5% in the surgery group (P=0.04).

CONCLUSION

At 5 years, the differences in mortality and combined incidence of death, CVA, and MI between coronary stenting and surgery did not reach statistically significant level. However, the occurrence of MACCE in the stent group was higher than in the CABG group, mainly driven by the higher incidence of repeat revascularization in the stent group.

A novel device for clampless proximal anastomosis in OPCAB surgery: the IPAD

The Coalescent IPAD (Coalescent Surgical, Sunnyvale, CA, USA) is a novel device that enables creation of a compliant proximal vein anastomosis to the aorta during off-pump coronary artery bypass (OPCAB) surgery while reducing the risk of cerebrovascular emboli and early stenosis. We performed IPAD-created anastomoses in 76 patients having standard OPCAB surgery. Following the procedures, no patients developed myocardial infarctions or reported angina, suggesting patency of the vein grafts to be of high quality. We found the device to be a useful adjunct for minimally invasive CAB graft surgery.

A new mechanical connector for distal coronary artery anastomoses in coronary artery bypass grafting: A randomized, controlled study

OBJECTIVE

A new mechanical anastomotic device was evaluated, aiming at its future use in minimally invasive techniques or limited access surgery in patients undergoing coronary artery bypass grafting.

METHODS

Between April and December 2002, a total of 60 patients scheduled for elective multivessel bypass grafting were randomly assigned. One vein graft-coronary artery anastomosis per patient was either performed with the St Jude Medical ATG coronary connector system (n = 30; St Jude Medical Inc, St Paul, Minn) or hand sewn (n = 30). Selective coronary angiography or coronary magnetic resonance imaging of the studied graft and vessel was included in the 6-month follow-up.

RESULTS

Twenty-eight of the connectors were successfully implanted. Two patients were excluded from the study because of conversion to hand-sewn anastomoses. Six connector-made anastomoses were bleeding at the anastomotic site. At the time of follow-up (190 postoperative days), all control anastomoses and grafts were patent, whereas 26% of the connector anastomoses were occluded. One graft in each group was patent but with stenosis.

CONCLUSION

The St Jude Medical ATG coronary connector system for distal anastomoses represents a new concept for sutureless anastomoses in cardiac surgery. This randomized, controlled study shows lower graft patency for anastomoses performed with the connector than for hand-sewn control anastomoses. It illustrates the importance of controlled studies when evaluating new technical equipment in medicine.

Prospective Evaluation of the St. Jude Medical Aortic Connector for Aortic-to-Autologous Vessel Graft Anastomoses

BACKGROUND

: Evolving technologies of proximal anastomosis devices meet the endeavor of surgeons to minimize manipulation of the ascending aorta during surgical myocardial revascularization. The objective of this study was to compare the patency rate of the saphenous vein coronary bypass grafts in which the proximal anastomoses were performed with automatic connector devices to the suture technique.

METHODS

: From September 2002 through July 2003, 86 patients underwent coronary artery bypass grafting with at least 1 vein graft anastomosed to the ascending aorta with the Symmetry G2 connector. Six-month clinical and angiographic follow-up, including Core-Lab quantitative coronary angiography (QCA) and corrected TIMI frame count (CTFC), was performed.

RESULTS

: Eighty patients had at least 1 connector successfully implanted. Freedom from MACE (cardiac mortality myocardial infarction and target vessel reintervention) was 72/80 (90%). Six patients underwent a target vessel reintervention on the connector grafts. Six-month (mean 193 ± 36 days) angiography patency rates for the connector grafts were 72/81 (88.89%), 37/40 (92.5%) in sutured grafts, and 60/62 (96.8%) in arterial grafts. By QCA, 64/65 (98.5%) patent connector-grafts were free from more than 50% stenosis (1 connector-graft with a 51% stenosis). CTFC showed 65/65 (100%) patent connector-grafts with nonrestrictive flow.

CONCLUSIONS

: Saphenous vein grafts anastomosed to the aorta with the Symmetry G2 connector have early and midterm patency rates comparable to the conventional sutured anastomoses. These results support the efficiency of the second generation of symmetry aortic connectors.

Intraoperative and intermediate-term angiographic results of coronary artery bypass surgery with Symmetry proximal anastomotic device

OBJECTIVE

The objective of this study was to investigate the patency in saphenous vein coronary bypass grafts in which the proximal anastomoses were performed with automatic connector devices or with a traditional suture technique.

METHODS

Forty-six patients underwent coronary artery bypass grafting without cardiopulmonary bypass by using one thoracic graft and one or more saphenous vein grafts. Grafts were attached to the aorta with a Symmetry connector (St Jude Medical, Inc, St Paul, Minn) in 23 patients, and partial occlusion of the aorta and sutured anastomoses were used in 23 other patients. Grafts were studied intraoperatively with transit time flowmetry and angiography and revised if necessary. Angiography was repeated after 3 to 5 months.

RESULTS

Intraoperative graft patency did not differ between the 2 groups. Follow-up angiography demonstrated excellent thoracic graft patency. Vein graft patency decreased to 50% in the Symmetry group, whereas it was 90% in the suture group ( P = .01). Twenty-five percent of the Symmetry grafts had significant stenosis in the connector.

CONCLUSION

Saphenous vein grafts anastomosed to aorta with the Symmetry proximal connector have low intermediate patency compared with those with traditionally sutured anastomoses. We do not recommend the routine use of this device in coronary artery bypass operations.

Virchow Triad, but Not Use of an Aortic Connector Device, Predicts Early Graft Failure after Off-Pump Coronary Bypass

The risk of early thrombosis of coronary artery bypass (CAB) grafts may be increased after off-pump CAB, particularly after the use of an aortic connector device (ACD) to perform the proximal aortosaphenous anastomosis. We have been investigating tools that quantify the risk of early vein graft thrombosis after off-pump CAB on the basis of the Virchow triad of hypercoagulability, endothelial disease, and low conduit flow. These tools were applied in this prospective trial of a heterogeneous group of patients with varying degrees of aortic disease and who received the Symmetry ACD. After controlling for the Virchow risk factor triad, we hypothesized that the ACD does not independently influence graft thrombosis. There was no statistically significant difference in the early thrombosis rates of vein grafts connected with an ACD versus hand-sewn grafts (6.7% versus 6.5%). We found a wide range of graft flow measurements, platelet function, and vein endothelial phenotypes in patients with traditionally hand-sewn vein grafts and with grafts connected with an ACD in patients with a wide range of ascending aortic atherosclerosis. The perioperative combination of platelet hyperreactivity, marginal graft flow, and endothelial disease proved to be highly predictive of early graft failure as seen with postoperative computed tomographic angiography.

Flow dynamics of the St Jude Medical Symmetry aortic connector vein graft anastomosis do not contribute to the risk of acute thrombosis

BACKGROUND

The efficacy of the St Jude Medical Symmetry aortic connector (St Jude Medical, Inc, St Paul, Minn) for coronary artery bypass is currently debated. Potential drawbacks are the biocompatibility of the endoluminal device, the need for graft manipulation during the procedure, and the 90 degrees offset of the vein graft from the ascending aorta, which may induce graft kinking and abnormal fluid dynamics. In this article, a computational approach was designed to investigate the fluid dynamics pattern at the proximal graft.

METHODS

Four models of hand-sewn anastomoses and two models of automated anastomoses were constructed; a finite volume technique was used to simulate realistic graft fluid dynamics, including aortic compliance and proper aortic and graft flow rates. The anastomosis geometry performance was analyzed by calculating time-averaged wall shear stress and the oscillating shear index at the toe and heel regions of the proximal graft.

RESULTS

Time-averaged wall shear stress was significantly lower in the hand-sewn anastomosis models than in the two models that simulated the use of the aortic connector (0.38 +/- 0.07 Pa vs 1.32 +/- 0.4 Pa). Higher oscillating shear index values were calculated in the hand-sewn anastomosis models (0.15 +/- 0.02 Pa vs 0.06 +/- 0.02 Pa).

CONCLUSIONS

Automated anastomosis geometry is associated with less critical fluid dynamics than with conventional hand-sewn anastomosis: the shape of the proximal graft induces more physiological wall shear stresses and less oscillating flow, suggesting a lower risk of atherosclerotic plaque and intimal hyperplasia as compared with conventional anastomosis geometry. Therefore, the reported early thrombosis and late failure of the St Jude Medical aortic connector anastomoses are not related to unfavorable fluid dynamics.

Initial experience with the Heartstring proximal anastomotic system

OBJECTIVE

Manipulation of the aorta has been shown to be associated with postoperative neurologic events after surgical myocardial revascularization when the aorta is diseased. The Heartstring proximal anastomotic system (Guidant, Indianapolis, Ind) is a device designed to assist in the performance of proximal anastomoses with minimal aortic manipulation. We describe our initial experience with this product.

METHODS

Twelve patients with a diseased aorta who underwent off-pump myocardial revascularization and had their proximal anastomoses performed with the Heartstring device were studied for operative and postoperative outcomes and surgical technique.

RESULTS

The mean age of the patients was 76 +/- 7 years. The estimated EuroSCORE perioperative mortality was 12% +/- 8%. The median number of distal anastomoses was 3. In all patients, a saphenous vein graft was anastomosed to the aorta using the Heartstring device. In 5 patients, the radial artery was used as a conduit and connected proximally to a left internal thoracic artery as a Y graft, to a saphenous vein graft as a "horseshoe," or on the hood of a saphenous vein graft. The operative and postoperative courses were uneventful. Three seals developed cracks and were not used. One seal developed an unravel in its periphery but was used successfully.

CONCLUSIONS

The Heartstring proximal anastomotic system is a device that allows the surgeon to perform standard proximal clampless anastomoses. Elderly patients with a diseased aorta may benefit from this device.

Sutureless Videoendoscopic Thoracic Aorta to Iliac Artery Bypass: The Easiest Approach to Occlusive Aorto-iliac Diseases

OBJECTIVE

We designed an animal study to determine the feasibility of videoendoscopic thoracic aorta to iliac artery bypass using a sutureless anastomotic device for proximal anastomosis construction.

METHODS

In 12 pigs the descending thoracic aorta was exposed using the thoracoscopic technique. A 4 mm PTFE thin wall graft was used as conduit. The proximal anastomosis was constructed using a mechanical device for sutureless anastomosis inserted through the camera port incision. The prosthesis was passed through the diaphragm in the retroperitoneal space and the distal anastomosis was done with running suture.

RESULTS

The operation was successfully completed in 11 animals. One animal died due to hemorrage during anastomosis construction. Mean graft flow was 144 ml/min (range 88-167 mmHg). The angiogram showed no graft kinking or stenosis. Total operative time was 58 min (range 47-68 min).

CONCLUSIONS

This approach allows quick and excellent exposure of the entire descending thoracic aorta. The use of the sutureless device to perform the proximal anastomosis dramatically reduces the technical demands of this procedure and could avoid an aortic clamp.

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

Recent developments in minimally invasive coronary artery surgery have been driven by the introduction of new technologies which should facilitate precise surgical maneuvers on the beating heart within confined spaces. Such technologies include coronary stabilizer systems, cardiac positioning vacuum-assisted devices, and telemanipulative systems. Despite these developments, standard suturing techniques using running polypropylene material remains a limiting factor in the surgeon's ability to perform complete revascularization with high quality anastomoses through minimal approaches to the chest cavity. Clinical validation of proximal and distal anastomotic devices has the potential to substantially improve and perhaps revolutionize minimally invasive coronary surgery. Ideal characteristics of such devices would include applicability to all conduit types, all coronary sizes, interchangeable proximal/distal sequencing of the anastomosis, and safe bail out for device malfunction. However there is an urgent need to define the performance objectives of such systems as well as the general criteria for proper and comparable evaluation and validation of different systems in animal models and subsequently in controlled prospective clinical studies. This review summarizes the most interesting systems available in both experimental and clinical settings.

Severe ostial saphenous vein graft disease leading to acute coronary syndromes following proximal aorto-saphenous anastomoses with the symmetry bypass connector device

The Symmetry Bypass Connector (St. Jude Medical, St. Paul, Minnesota) is a nitinol, star-shaped device that was designed to facilitate placement of sutureless aorto-saphenous anastomoses during off-pump coronary artery bypass graft surgery (CABG). Although the device is approved for clinical use in Europe and the U.S., its short- and long-term safety and efficacy are not established. We report on 5 of 121 patients undergoing CABG who presented with an acute coronary syndrome two to five months following placement of this device. In each patient, all saphenous vein grafts (SVGs) placed (n = 11) with the device were totally occluded (n = 6) or compromised by ostial stenoses (n = 5). Treatment consisted of repeat CABG in one patient and percutaneous coronary intervention (PCI) in four patients with cutting balloon atherotomy and stenting. Following PCI, two of four patients presented again within two months with near-occlusive ostial restenosis in all stents placed. Intracoronary ultrasound showed severe neointimal hyperplasia, but only at the proximal interface of the device and stent. One patient was treated with brachytherapy in two SVGs but had a recurrence four months later and was treated with drug-eluting stents in both restenotic segments. Recalcitrant neointimal hyperplasia is postulated to be involved in the pathogenesis of anastomotic device stenosis, possibly similar to in-stent restenosis. Prospective randomized clinical trials are needed to assess the clinical safety and efficacy of this device. Pending such studies, consideration should be given in limiting its use to cases of unacceptably high risk of stroke during aortic cross-clamping. Dual antiplatelet agents, evaluation for ischemia, and close follow-up are warranted in patients that have already received the device.