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

Immediate stent recoil in an anastomotic vein graft lesion treated by cutting balloon angioplasty

Saphenous vein graft (SVG) anastomotic lesions can have significant fibromuscular hyperplasia and may be resistant to balloon angioplasty alone. Stents have been used successfully to treat these lesions. There are no reports of immediate stent recoil following such treatment in the literature. We describe immediate and persistent stent recoil in an anastomotic SVG lesion even after initial and post-deployment complete balloon dilatation of the stent and its successful treatment by cutting balloon angioplasty.

Combined aortic valve replacement and coronary artery bypass grafting for a calcified ascending aorta

Although a severely calcified ascending aorta is encountered infrequently, it presents formidable problems during cardiac surgery. We describe a case of severe aortic valve stenosis and coronary artery disease combined with a severely calcified ascending aorta. The patient was an 80-year-old man with a calcified ascending aorta. He successfully underwent an aortic valve replacement and a single coronary artery bypass graft (CABG) using a saphenous vein graft with the proximal end connected on a Dacron patch, which was used for aortoplasty of the calcified plate along the aortotomy. These procedures were performed under moderate hypothermia with aortic clamping. This patch aortoplasty can be a useful alternative in cases that require aortotomy and proximal anastomoses of a CABG on a calcified ascending aorta.

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.

Safe introduction and quality control of new methods in coronary surgery

Introduction:

The first part of the paper analyses off pump coronary bypass surgery (OPCAB), which is compared with traditional on-pump procedures (ONCAB). Furthermore ,the paper evaluates the use of a new automatic device for performance of the proximal anastomosis and finally the effect of intracoronary shunt on myocardial ischemia during OPCAB. The main goal of the paper is to demonstrate the importance of careful clinical studies during introduction of the new techniques in cardiac surgery.

Methods:

Statistical analysis was performed on a large clinical database from Buffalo, NY, USA comparing OPCAB and ONCAB. Subsequently, a sequential controlled clinical study compared patients operated with a new automatic connector device to patients operated with classic suture technique. Finally a randomized study was performed to evaluate the effect of the use of an intracoronary shunt during construction of distal anastomosis.

Results:

The studies from Buffalo demonstrated reduced complications rates in high risk patients when OPCAB techniques were used. The use of connector devices in saphenous venous anastomosis was clearly inferior to standard technique. Intracoronary shunt was found to be beneficial by preventing ischemia.

Discussion:

Numerous studies have studied the results of OPCAB vs ONCAB and although results are variable it seems that OPCAB is advantageous in high risk patients, while in low risk patients there are much less if any benefit. The results of the studies of connector devices caused the product to be taken off the market. The value of shunt in OPCAB was clearly demonstrated by the randomized studies.

Conclusion:

The investigations presented in this paper clearly demonstrates the importance of well-designed studies when new surgical methods are introduced. In the present period of rapid technological development, carefully controlled, un-biased clinical trials are crucial to preserve patient safety and avoid unjustified societal cost.

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.

Study of coronary artery bypass using the PAS-Port device: assessment by multidetector computed tomography

OBJECTIVE

The use of automatic anastomotic devices in coronary artery bypass grafting surgery is associated with lower patency rates in comparison to conventional anastomosis methods. This is thought to be caused by graft curvature occurring after closing of the chest wall.

METHODS

We evaluated 39 grafts in 28 patients who underwent off-pump coronary artery bypass surgery using the PAS-Port. After surgery, the proximal anastomotic angle of each stent, graft morphology, and patency were evaluated with axial and sagittal views.

RESULTS

The angle for the left anterior descending coronary artery segment was relatively obtuse on the left side of the ascending aorta, and the graft loop formation was not necessary. The angle for the left circumflex coronary artery segment was significantly acute for anastomosis from the upper left side of the ascending aorta. Because grafts are under the constraints of a large loop, graft length tended to become easily excessive or deficient. The angle for the right coronary artery segment was relatively obtuse. The space on the right side of the heart was so narrow that in some cases we had difficulty setting out the appropriate graft location to prevent graft curvature. No bending or stenosis was present in any graft, showing a patency rate of 100%.

CONCLUSION

The short-term results of coronary bypass grafting using PAS-Port are satisfactory.

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.

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.

Corrosion of stainless steel sternal wire after long-term implantation

A variety of metallic components have been used in medical devices where lifelong durability and physical strength are demanded. To investigate the in vivo changes of implanted metallic medical devices in humans, stainless steel sternal wires removed from patients were evaluated. Stainless steel (316L) sternal wires removed from four patients after 10, 13, 22, and 30 years of implantation were evaluated using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Macroscopically, the removed specimens maintained their metallic luster and color. Under SEM, small holes were observed sporadically at 10 years and they tended to connect in the drawing direction. The longer the implanted duration, the more numerous and deeper were the crevices observed. By EDS, sulfur, phosphorus, and calcium were identified in all areas at 10 years, in addition to the component elements of stainless steel, comprising iron, chromium, nickel, and manganese. Corrosion products observed at 30 years were identified as calcium phosphate. In conclusion, stainless steel sternal wires develop corroded pores that grow larger and deeper with time after implantation; however, the pores remain shallow even after decades of implantation and they may not be a cause of mechanical failure. An amount of metal ions equivalent to the corroded volume must have been released into the human body, but the effect of these metal ions on the body is not apparent.

Long-term outcomes of the symmetry vein graft anastomosis device: a matched case-control analysis

BACKGROUND

The Symmetry Bypass Connector (St. Jude Medical) was developed to rapidly anastomose saphenous vein grafts to the aorta during coronary bypass surgery (CABG) without cross-clamping. Previous uncontrolled studies of this device observed vein graft closures at six months, possibly attributable to neointimal hyperplasia.

METHODS AND RESULTS

To assess the long-term clinical outcomes of the Symmetry device, we performed a retrospective matched case-control analysis of patients who underwent CABG at Duke Medical Center between January 1, 2002 and December 31, 2003. In 121 patients, at least one proximal anastomosis used a Symmetry device. Traditional suture methods were used in 178 control patients, matched by age group, gender, use of cardiopulmonary bypass, and Hannan perioperative risk score. One-year outcomes were compared using the log-rank test and Cox proportional hazards regression models. Major adverse events were more frequent among cases compared with controls. By unadjusted Kaplan-Meier analysis for the composite end point of death, nonfatal myocardial infarction, repeat cardiac catheterization, or repeat CABG, there was a trend towards increased events in the Symmetry device group (P=0.053). No significant differences were detected for stroke, all cause mortality, or the combined end point of death or nonfatal myocardial infarction.

CONCLUSIONS

Use of the Symmetry Bypass Connector was associated with increased risk for major adverse events at 1 year, suggestive of early graft closure. The potential reductions in operative stroke risk (from the elimination of aortic cross-clamping) must be weighed against the potential risk for later adverse events. These findings encourage close follow-up of patients who received this device.

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.

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.

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.

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.

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.