A novel device for left atrial appendage exclusion: The third-generation atrial exclusion device

A comparison between stand-alone left atrial appendage occlusion and resection as a method of preventing cardiogenic thromboembolic stroke

OBJECTIVE

The present study evaluated the differences between left atrial appendage occlusion (LAAO) and left atrial appendage resection (LAAR) in terms of the safety and efficacy.

MATERIALS AND METHODS

From January 2018 to August 2022, 94 patients underwent a stand-alone LAAO, and 90 patients underwent stand-alone LAAR in our institution. All of these patients were included in this study. LAAO was performed via left mini-thoracotomy, and LAAR was performed via a left thoracoscopic approach. The patients' characteristics and perioperative and postoperative data were obtained by retrospectively reviewing their medical records.

RESULTS

The mean age of the patients was 72.4 ± 10.2 (LAAO) and 66.2 ± 9.4 (LAAR) years old (P < 0.05). There were no marked differences in the mean duration of atrial fibrillation (AF) or the ratio of AF type between both groups. The average CHA2DS2-Vasc scores were 4.4 ± 1.6 (LAAO) and 2.7 ± 1.8 (LAAR) (P < 0.05), and the average HAS-BLED scores were 2.9 ± 1.0 (LAAO) and 2.2 ± 1.2 (LAAR) (P < 0.05). The mean operation time was 49 ± 20 min (LAAO) and 34 ± 15 min (LAAR) (P < 0.05). No substantial gaps were detected in preoperative echo-graphic findings between the groups. No significant differences were observed in the amount of intraoperative or postoperative bleeding or the rate of intraoperative massive bleeding events between the groups. Successful LAA closure was achieved in all cases in both groups. Approximately 50% of patients underwent concomitant left pulmonary vein isolation (LPVI) during surgery, indicating no significant differences between the groups (P = 0.872). The early mortality rate was 1.04% in the LAAO group and 0% in the LAAR group (P = 0.132). There was no significant difference in the rate of postoperative LAA stump thrombus between the groups (8.5% in the LAAO group and 6.7% in the LAAR group; P = 0.320). The mean follow-up period was 851 ± 500 (6-1618) days in the LAAO group and 1208 ± 357 (49-1694) days in the LAAR group. Postoperative stroke events were detected in 1 patient in each group (P = 0.432). There was no significant difference in the sinus rhythm recovery rate after LPVI between these groups (31.1% in the LAAO group and 28.6% in the LAAR group; P = 0.763).

CONCLUSION

There were no significant differences between LAAO and LAAR in terms of the feasibility and the effectiveness as a method for stroke prophylaxis only to selected patients for both procedures, although further studies including the comparison between groups with the same backgrounds to confirm the authentic differences in the clinical results between these procedures.

Concomitant surgery of minimally invasive direct coronary artery bypass with left atrium appendage closure

Surgical approaches of minimally invasive direct coronary artery bypass and left atrial appendage exclusion are different, and issues may arise in cases of concomitant surgery. Moreover, the safety of concomitant procedures has not been established. A man in his 80s with a history of stroke required minimally invasive coronary artery bypass grafting and left atrial appendage closure for the stenosis of the left anterior descending artery and atrial fibrillation. He suffered from bladder bleeding, which required early reduction of anticoagulant and antiplatelet medication. Therefore, he wished for surgical treatment. A lateral incision was necessary for left atrial appendage closure in minimally invasive surgery. We performed totally endoscopic harvest of the internal thoracic artery without a robotic system. This method allowed the incision to be made more laterally. Combining the endoscopic harvest of the internal mammary artery with left atrial appendage closure via lateral incision may be a reasonable technique.

The left atrial appendage closure by surgery-2 (LAACS-2) trial protocol rationale and design of a randomized multicenter trial investigating if left atrial appendage closure prevents stroke in patients undergoing open-heart surgery irrespective of preoperative atrial fibrillation status and stroke risk

BACKGROUND

Current recommendations regarding the use of surgical left atrial appendage (LAA) closure to prevent thromboembolisms lack high-level evidence. Patients undergoing open-heart surgery often have several cardiovascular risk factors and a high occurrence of postoperative atrial fibrillation (AF)-with a high recurrence rate-and are thus at a high risk of stroke. Therefore, we hypothesized that concomitant LAA closure during open-heart surgery will reduce mid-term risk of stroke independently of preoperative AF status and CHA2DS2-VASc score.

METHODS

This protocol describes a randomized multicenter trial. Consecutive participants ≥18 years scheduled for first-time planned open-heart surgery from cardiac surgery centers in Denmark, Spain, and Sweden are included. Both patients with a previous diagnosis of paroxysmal or chronic AF, as well as those without AF, are eligible to participate, irrespective of their CHA2DS2-VASc score. Patients already planned for ablation or LAA closure during surgery, with current endocarditis, or where follow-up is not possible are considered noneligible. Patients are stratified by site, surgery type, and preoperative or planned oral anticoagulation treatment. Subsequently, patients are randomized 1:1 to either concomitant LAA closure or standard care (ie, open LAA). The primary outcome is stroke, including transient ischemic attack, as assigned by 2 independent neurologists blinded to the treatment allocation. To recognize a 60% relative risk reduction of the primary outcome with LAA closure, 1,500 patients are randomized and followed for 2 years (significance level of 0.05 and power of 90%).

CONCLUSIONS

The LAACS-2 trial is likely to impact the LAA closure approach in most patients undergoing open-heart surgery.

TRIAL REGISTRATION

NCT03724318.

The Strengths and Weaknesses of Left Atrial Appendage Ligation or Exclusion (LARIAT, AtriaClip, Surgical Suture)

Left atrial appendage (LAA) epicardial exclusion has been associated with addressing 2 potential deleterious consequences attributed to the LAA, namely, thrombus formation and an arrhythmogenic contributor in advanced forms of atrial fibrillation. With more than 60 years of history, the surgical exclusion of the LAA has been firmly established. Numerous approaches have been used for surgical LAA exclusion including surgical resections, suture ligation, cutting and non-cutting staples, and surgical clips. Additionally, a percutaneous epicardial LAA ligation approach has been developed. A discussion of the various epicardial LAA exclusion approaches and their efficacy will be discussed, along with the salient beneficial affects on LAA thrombus formation, LAA electrical isolation and neuroendocrine homeostasis.

Left Atrial Appendage Occlusion: Current Stroke Prevention Strategies and a Shift Toward Data-Driven, Patient-Specific Approaches

The left atrial appendage (LAA) is a complex structure with unknown physiologic function protruding from the main body of the left atrium. In patients with atrial fibrillation, the left atrium does not contract effectively. Insufficient atrial and LAA contractility predisposes the LAA morphology to hemostasis and thrombus formation, leading to an increased risk of cardioembolic events. Oral anticoagulation therapies are the mainstay of stroke prevention options for patients; however, not all patients are candidates for long-term oral anticoagulation. Percutaneous occlusion devices are an attractive alternative to long-term anticoagulation therapy, although they are not without limitations, such as peri-implant leakage and device-related thrombosis. Although efforts have been made to reduce these risks, significant interpatient heterogeneity inevitably yields some degree of device-anatomy mismatch that is difficult to resolve using current devices and can ultimately lead to insufficient occlusion and poor patient outcomes. In this state-of-the-art review, we evaluated the anatomy of the LAA as well as the current pathophysiologic understanding and stroke prevention strategies used in the management of the risk of stroke associated with atrial fibrillation. We highlighted recent advances in computed tomography imaging, preprocedural planning, computational modeling, and novel additive manufacturing techniques, which represent the tools needed for a paradigm shift toward patient-centric LAA occlusion. Together, we envisage that these techniques will facilitate a pipeline from the imaging of patient anatomy to patient-specific computational and bench-top models that enable customized, data-driven approaches for LAA occlusion that are engineered specifically to meet each patient's unique needs.

The Strengths and Weaknesses of Left Atrial Appendage Ligation or Exclusion (LARIAT, AtriaClip, Surgical Suture)

Left atrial appendage (LAA) epicardial exclusion has been associated with addressing 2 potential deleterious consequences attributed to the LAA, namely, thrombus formation and an arrhythmogenic contributor in advanced forms of atrial fibrillation. With more than 60 years of history, the surgical exclusion of the LAA has been firmly established. Numerous approaches have been used for surgical LAA exclusion including surgical resections, suture ligation, cutting and non-cutting staples, and surgical clips. Additionally, a percutaneous epicardial LAA ligation approach has been developed. A discussion of the various epicardial LAA exclusion approaches and their efficacy will be discussed, along with the salient beneficial affects on LAA thrombus formation, LAA electrical isolation and neuroendocrine homeostasis.

Standalone epicardial left atrial appendage exclusion for thromboembolism prevention in atrial fibrillation

OBJECTIVES

Most strokes associated with atrial fibrillation (AF) result from left atrial appendage thrombi. Oral anticoagulation can reduce stroke risk but is limited by complication risk and non-compliance. Left atrial appendage exclusion (LAAE) is a new surgical option to reduce stroke risk in AF. The study objective was to evaluate the safety and feasibility of standalone thoracoscopic LAAE in high stroke risk AF patients.

METHODS

This was a retrospective, multicentre study of high stroke risk AF patients who had oral anticoagulation contraindications and were not candidates for ablation nor other cardiac surgery. Standalone thoracoscopic LAAE was performed using 3 unilateral ports access and epicardial clip. Periprocedural adverse events, long-term observational clinical outcomes and stroke rate were evaluated.

RESULTS

Procedural success was 99.4% (174/175 patients). Pleural effusion occurred in 4 (2.3%) patients; other periprocedural complications were <1% each. One perioperative haemorrhagic stroke occurred (0.6%). No phrenic nerve palsy or cardiac tamponade occurred. Predicted annual ischaemic stroke rate of 4.8/100 patient-years (based on median CHA2DS2-VASc score of 4.0) was significantly higher than stroke risk observed in follow-up after LAAE. No ischaemic strokes occurred (median follow-up: 12.5 months), resulting in observed rate of 0 (95% CI 0-2.0)/100 patient-years (P < 0.001 versus predicted). Six all-cause (non-device-related) deaths occurred during follow-up.

CONCLUSIONS

Study proved that a new surgical option, standalone thoracoscopic LAAE, is feasible and safe. With this method, long-term stroke rate may be reduced compared to predicted for high-risk AF population.

Early and Middle-Term Results and Anticoagulation Strategy after Left Atrial Appendage Exclusion Using an Epicardial Clip Device

Objective: The present study aimed to evaluate short- and middle-term results and postoperative anticoagulation of left atrial appendage (LAA) exclusion with an epicardial clip device.

Materials and Methods: From September 2017 to August 2019, 102 patients at our institution underwent epicardial LAA exclusion using the AtriClip device. Anticoagulation therapy was resumed in the very early postoperative period and continued for at least three months after surgery. The patients’ data were obtained by reviewing their medical records retrospectively.

Results: The mean and median durations of follow-up was 510 ± 184 days and 482 days (range, 216–938 days), respectively. Successful LAA exclusion was confirmed in all but one patient. No device-related complications occurred during surgery. Postoperative computed tomography (CT) findings revealed no migration or displacement of the clips in any patient; however, small clots were observed at the LAA stump in seven patients. Stroke-free rate during the follow-up period was 98.9%.

Conclusion: LAA exclusion using the AtriClip device was a feasible treatment method in terms of its early and middle-term safety and efficacy. In addition, our postoperative anticoagulation strategy could be optimal for maximizing the procedure’s merits, although further studies, involving a larger number of patients and longer duration of follow-up, are needed.

Clip-and-loop technique for left atrial appendage occlusion

The left atrial appendage is thought to be responsible for the majority of embolic strokes, and has become an important target in the surgical management of atrial fibrillation. We present an original clip-and-loop technique using an AtriClip via a left minithoracotomy for post-stroke patients with atrial fibrillation. This procedure was performed in 43 cases between March 2018 and January 2020. No patient had a thrombus at the edge of the clip or communication into the left atrial appendage 3 months after surgery. Anticoagulant could be discontinued in all patients. Follow-up at 23 ± 10 months showed no recurrence of stroke.

Evaluation of Local Tissue Reaction After the Application of a 3D Printed Novel Holdfast Device for Left Atrial Appendage Exclusion

The left atrial appendage (LAA) is a small, finger-like extension of the left atrium and its exclusion is used as a treatment strategy to prevent ischemic stroke. Existing holdfast devices may damage the tissue, are unisized and not adjustable. A novel holdfast device for LAA exclusion devoid of these shortcomings was designed and 3D-printed using the Selective Laser Sintering (SLS) technology with polyamide powder and tested it on animal model. We selected the SLS 3D printing technology due to its wid14e availability and low production costs which could provide on-site 3D printing for specific patient. The purpose of this study was to evaluate the biocompatibility of the reported holdfast device and compare the histological results obtained for local tissue reactions to those obtained for an established grafting material. Thirty swine subdivided into two groups were examined. The LAA exclusion device was implanted and was either coated with a polyester vascular implant or not coated at all and the histological response to the device’s presence was evaluated which is a standard approach to test the device biocompatibility. In all cases, complete occlusion was seen without any pathological findings during the incubation time. In both groups, the surface of the atrium under a holdfast device was smooth and shiny and had no clots. The foreign body reaction of the LAA holdfast device made of polyamide powder was insignificantly lower compared to the polyester graft. Thus, it fulfils the parameters of biocompatibility at the highest degree, and makes it suitable material for the manufacturing of LAA holdfast devices.

Left atrial appendage isolation in atrial fibrillation catheter ablation: A meta-analysis

A significant proportion of patients' experience recurrence of atrial fibrillation (AF) despite pulmonary venous isolation (PVI), especially those with persistent AF. Isolation of the left atrial appendage (LAA) may reduce AF recurrence. The aim of this study was to assess the efficacy of LAA isolation in addition to PVI compared with PVI alone. We conducted a comprehensive search of electronic databases, up to April 21st, 2017, for all studies comparing the effect LAA electrical isolation or ligation in addition to PVI, as opposed to PVI alone, on the recurrence of atrial fibrillation after catheter ablation. We used random-effects meta-analysis models to summarize the studies. One RCT and four observational studies enrolling 781 patients were retained. Four studies assessed the added effect of LAA catheter ablation, and one study evaluated the effect of LAA ligation with the aim of LAA electrical isolation. Four studies exclusively enrolled patients with persistent atrial fibrillation and one study predominantly enrolled patients with persistent atrial fibrillation. Follow-up ranged from 12 to 15 months. The addition of LAA isolation to PVI reduced AF recurrence compared with the latter alone (odds ratio (OR) = 0.19; 95% confidence intervals (CI) = 0.10-0.37; P < 0.00001). Left atrial appendage isolation was also associated with a reduction in AF recurrence after repeat ablation (OR = 0.40; CI = 0.25-0.65; P = 0.0003). The addition of LAA isolation to PVI was associated with a decrease in AF recurrence in patients with persistent AF. Further studies are needed to assess the effect on long-term risk of stroke.

Approaches to Left Atrial Appendage Closure: Device Design, Performance, and Limitations

Up to 6.1 million people in the United States have atrial fibrillation (AF), which is associated with an increased risk of stroke. Oral anticoagulants are the mainstay of stroke prevention in AF. For decades, warfarin was the only available drug, fraught with compliance limitations, a narrow therapeutic window, and a high risk of hemorrhage. Pharmacologic developments have produced new anticoagulants that have improved the rates of stroke related to AF; however, they still confer a high risk of bleeding, making them unsuitable for some patients. Studies have shown that roughly 90% of strokes in patients with AF occur in the left atrial appendage (LAA). This understanding has prompted the development and testing of novel percutaneous strategies for LAA closure as an alternative to anticoagulation therapy. The following review examines the relative merits and shortcomings of these strategies and explores future prospects in the prevention of AF-related stroke.

2017 consensus of the Asia Pacific Heart Rhythm Society on stroke prevention in atrial fibrillation

Atrial fibrillation (AF) is the most common sustained arrhythmia, causing a 2-fold increase in mortality and a 5-fold increase in stroke. The Asian population is rapidly aging, and in 2050, the estimated population with AF will reach 72 million, of whom 2.9 million may suffer from AF-associated stroke. Therefore, stroke prevention in AF is an urgent issue in Asia. Many innovative advances in the management of AF-associated stroke have emerged recently, including new scoring systems for predicting stroke and bleeding risks, the development of non-vitamin K antagonist oral anticoagulants (NOACs), knowledge of their special benefits in Asians, and new techniques. The Asia Pacific Heart Rhythm Society (APHRS) aimed to update the available information, and appointed the Practice Guideline sub-committee to write a consensus statement regarding stroke prevention in AF. The Practice Guidelines sub-committee members comprehensively reviewed updated information on stroke prevention in AF, emphasizing data on NOACs from the Asia Pacific region, and summarized them in this 2017 Consensus of the Asia Pacific Heart Rhythm Society on Stroke Prevention in AF. This consensus includes details of the updated recommendations, along with their background and rationale, focusing on data from the Asia Pacific region. We hope this consensus can be a practical tool for cardiologists, neurologists, geriatricians, and general practitioners in this region. We fully realize that there are gaps, unaddressed questions, and many areas of uncertainty and debate in the current knowledge of AF, and the physician׳s decision remains the most important factor in the management of AF.

Novel stroke risk reduction in atrial fibrillation: left atrial appendage occlusion with a focus on the Watchman closure device

Atrial fibrillation (AF) remains an important clinical problem with severe complications such as stroke, which especially harms those with risk factors as calculated by the CHADS2 or CHA2DS2-VASc. Until now, no therapy has proven 100% effective against AF. Since the left atrial appendage (LAA) is the most prominent nonvalvular AF-related thromboembolic source and (novel) oral anticoagulant [(N)OAC] carries the hazard of bleeding, LAA occlusion may be an alternative, especially in patients who are ineligible for (N)OAC therapy. In this review, we discuss several LAA occlusion techniques with a focus on the Watchman device since this device is the most thoroughly studied device of all.

Concomitant Left Atrial Appendage Clipping During Minimally Invasive Mitral Valve Surgery: Technically Feasible and Safe

BACKGROUND

It is believed that most of thrombi form in the left atrial appendage (LAA)before they emboli. Different surgical and percutaneouse approaches were suggested to manage the LAA. In this study we are evaluating the safety of clipping the LAA via minithoractotomy approach.

METHOD

All consecutive patients who had minimally invasive mitral valve surgery with concomitant LAA clipping between December 2012 and February 2014 were included in the study. LAA exclusion was performed using AtriClip® LAA Exclusion System (Cincinnati, Ohio, AtriCure®). The patient s' clinical characteristics, intraoperative complications, and in-hospital coarse were obtained by reviewing the medical records.

RESULT

Total of 22 patients(50% males) were included in the study. The median ages was 66.0 years (IQR: 50.8 to 81.3). Eight(36%) had mitral valve replacement and the rest had mitral repair surgery. Five(23%) patients needed blood product transfusion during the surgery. No clip related bleeding was observed and no perioperative mortality was recorded.

CONCLUSION

During minimally invasive mitral valve surgery, Concomitant exclusion of the left atrial appendage using AtriClip® can be performed rapidly and safely.

Combined Ablation and Exclusion of the Left Atrial Appendage in a Pediatric Patient: A Minimally Invasive Simplified Approach

We present the first reported case of totally video-assisted thoracoscopic surgery for combined ablation and external exclusion without appendectomy of the left atrial appendage. We encourage the use of video-assisted thoracoscopic surgery for a combined procedure of epicardial radiofrequency ablation and external exclusion without appendectomy to achieve a safe and complete electrical isolation of the left atrial appendage in children with focal atrial tachycardia. In our opinion, the external exclusion of the appendage has several advantages: it presents minimal risk of bleeding (especially in the pediatric population), and the clip can be retrieved if the circumflex artery is distorted.

The New 3D Printed Left Atrial Appendage Closure with a Novel Holdfast Device: A Pre-Clinical Feasibility Animal Study

INTRODUCTION

Many patients undergoing cardiac surgery have risk factors for both atrial fibrillation (AF) and stroke. The left atrial appendage (LAA) is the primary site for thrombi formation. The most severe complication of emboli derived from LAA is stroke, which is associated with a 12-month mortality rate of 38% and a 12-month recurrence rate of 17%. The most common form of treatment for atrial fibrillation and stroke prevention is the pharmacological therapy with anticoagulants. Nonetheless this form of therapy is associated with high risk of major bleeding. Therefore LAA occlusion devices should be tested for their ability to reduce future cerebral ischemic events in patients with high-risk of haemorrhage.

AIM

The aim of this study was to evaluate the safety and feasibility of a novel left atrial appendage exclusion device with a minimally invasive introducer in a swine model.

MATERIALS AND METHODS

A completely novel LAA device, which is composed of two tubes connected together using a specially created bail, was designed using finite element modelling (FEM) to obtain an optimal support force of 36 N at the closure line. The monolithic form of the occluder was obtained by using additive manufacturing of granular PA2200 powder with the technology of selective laser sintering (SLS). Fifteen swine were included in the feasibility tests, with 10 animals undergoing fourteen days of follow-up and 5 animals undergoing long-term observation of 3 months. For one animal, the follow-up was further prolonged to 6 months. The device was placed via minithoracotomy. After the observation period, all of the animals were euthanized, and their hearts were tested for LAA closure and local inflammatory and tissue response.

RESULTS

After the defined observation period, all fifteen hearts were explanted. In all cases the full closure of the LAA was achieved. The macroscopic and microscopic evaluation of the explanted hearts showed that all devices were securely integrated in the surrounding tissues. No pericarditis or macroscopic signs of inflammation at the site of the device were found. All pigs were in good condition with normal weight gain and no other clinical symptoms.

CONCLUSION

This novel 3D printed left atrial appendage closure technique with a novel holdfast device was proven to be safe and feasible in all pigs. A benign healing process without inflammation and damage to the surrounding structures or evidence of new thrombi formation was observed. Moreover, the uncomplicated survival and full LAA exclusion in all animals demonstrate the efficacy of this novel and relatively cheap device. Further clinical evaluation and implementation studies should be performed to introduce this new technology into clinical practice.

Percutaneous Left Atrial Appendage Ligation for Stroke Prevention in Atrial Fibrillation

Prevention of thromboembolic complications in atrial fibrillation remains a tremendous clinical challenge. Knowledge that the left atrial appendage (LAA) is the most common anatomical origin of cardioembolic strokes1 has been the main motivation to develop clinical and procedural strategies to exclude the LAA from the circulation, either surgically or percutaneously. This review discusses the rationale behind these strategies, their relative merits, and future prospects for LAA exclusion strategies.

Mechanical closure devices for atrial fibrillation

Atrial fibrillation (AF) is the most commonly sustained arrhythmia and is a major cause of stroke and systemic embolism. Chronic oral anticoagulation reduces this risk, but at the cost of increased bleeding. In addition, a substantial proportion of AF patients who are at moderate-to-high risk for stroke are undertreated due to real or perceived contraindications. The major source of thromboembolism in AF appears to be the left atrial appendage (LAA). Therefore, device closure of the LAA represents a mechanical approach to stroke prevention in AF patients. In this review, we describe the rationale for device closure of the LAA, summarize the current dataset for LAA closure devices, and set forth a framework to help guide patient selection for device therapy.

Managing the Left Atrial Appendage in the Era of Minimally Invasive Surgery

Atrial fibrillation (AF) is the most prevalent arrhythmia encountered in clinical practice with greater than 2.2 million people in the United States being affected. Oral anticoagulant therapy has been used to reduce risk of stroke in patients with nonvalvular AF who are at a high risk of thromboembolism. Alternative treatment strategies to prevent thromboembolism have been tested in patients with AF. This article examines the history of left atrial appendage occlusion and the efficacy of the various surgical techniques and provides a brief overview of the minimally invasive surgical strategy adopted to manage the left atrial appendage.

Left Atrial Appendage Closure for Stroke Prevention: Emerging Technologies

Current anticoagulant therapies aimed at stroke prevention in atrial fibrillation (AF) are increasingly challenged by a complex patient population at significant risk of bleeding. Mounting evidence shows that left atrial appendage (LAA) closure is an effective strategy for reducing stroke risk in patients with nonvalvular AF, without the need for anticoagulation. Several approaches and devices have been developed in recent years, each with their own set of advantages and disadvantages. This article reviews these approaches, identifies pertinent aspects, and outlines necessary or ongoing research in establishing LAA closure as a safe and effective approach to stroke risk reduction.

Guideline for the surgical treatment of atrial fibrillation

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and its prevalence is ∼1-2% of the general population, but higher with increasing age and in patients with concomitant heart disease. The Cox-maze III procedure was a groundbreaking development and remains the surgical intervention with the highest cure rate, but due to its technical difficulty alternative techniques have been developed to create the lesions sets. The field is fast moving and there are now multiple energy sources, multiple potential lesion sets and even multiple guidelines addressing the issues surrounding the surgical treatment of AF both for patients undergoing this concomitantly with other cardiac surgical procedures and also as stand-alone procedures either via sternotomy or via videothoracoscopic techniques. The aim of this document is to bring together all major guidelines in this area into one resource for clinicians interested in surgery for AF. Where we felt that guidance was lacking, we also reviewed the evidence and provided summaries in those areas. We conclude that AF surgery is an effective intervention for patients with all types of AF undergoing concomitant cardiac surgery to reduce the incidence of AF, as demonstrated in multiple randomized studies. There is some evidence that this translates into reduced stroke risk, reduced heart failure risk and longer survival. In addition, symptomatic patients with AF may be considered for surgery after failed catheter intervention or even as an alternative to catheter intervention where either catheter ablation is contraindicated or by patient choice.

Left atrial appendage occlusion: pilot study of a fourth-generation, minimally invasive device

OBJECTIVE

Exclusion of the left atrial appendage is proposed to reduce the risk of stroke in patients with atrial fibrillation. The aim of this study was to evaluate the feasibility and efficacy of a fourth-generation atrial exclusion device developed for minimally invasive applications.

METHODS

The novel atrial exclusion device consists of two polymer beams and two elastomeric bands that connect the two beams at either end. Fifteen mongrel dogs were implanted with the device at the base of the left atrial appendage through a median sternotomy and were evaluated at 30 (n = 7), 90 (n = 6), and 180 (n = 2) days after implantation by epicardial echocardiography, left atrial and coronary angiography, gross pathology, and histology.

RESULTS

Left atrial appendage exclusion was completed without hemodynamic instability. Coronary angiography revealed that the left circumflex artery was patent in all cases. A new endothelial tissue layer developed, as expected, on the occluded orifice of the left atrium.

CONCLUSIONS

This novel atrial exclusion device achieved easy, reliable, and safe exclusion of the left atrial appendage, with favorable histological results in a canine model for up to 6 months. Clinical application could provide a new therapeutic option for reducing the risk of stroke in patients with atrial fibrillation.

Surgery for atrial fibrillation: recent progress and future perspective

Development and introduction of radiofrequency ablation devices allowed the maze procedures to be performed safely and easily, further enabling off-pump pulmonary vein isolation through a mini-thoracotomy or thoracoscope. The effects of the maze procedure include prevention of stroke and other complications related to atrial fibrillation, improved cardiac performance, and relief of symptoms. Indications for the maze procedure have been discussed on the basis of the evidence. Pulmonary vein isolation has been shown to be effective in most patients with paroxysmal atrial fibrillation and can be performed with endocardial catheter ablation and minimally invasive epicardial ablation. These two modalities should be compared in terms of the success rate, occurrence of cerebral microembolic signals, capability of additional lesions indicated for persistent or long-standing persistent atrial fibrillation, and closure of the left atrial appendage. Noncontinuous or nontransmural lines of conduction block as a result of incomplete ablation can result in recurrence of atrial fibrillation and induction of atrial tachycardia. Intraoperative verification of conduction block across the ablation lines is recommended to prevent these complications. Volume reduction of the enlarged left atrium or a boxlesion to isolate the entire posterior left atrium may be effective in patients with a dilated left atrium, but the potentially impaired atrial transport function should be considered. Mapping of active ganglionated plexi and their ablation may improve the outcome of the procedure, but the long-term effect on atrial fibrillation and autonomic nerve activities should be examined.

Exclusion of the left atrial appendage with a novel device: early results of a multicenter trial

OBJECTIVE

Up to 90% of embolic strokes that occur in patients with atrial fibrillation originate from the left atrial appendage. Exclusion of the left atrial appendage during cardiac surgery may decrease the future risk of stroke, especially in patients with atrial fibrillation or at high risk for developing atrial fibrillation. We report the initial results of a multicenter Food and Drug Administration trial to assess the safety and efficacy of a novel left atrial appendage exclusion clip.

METHODS

Patients undergoing elective cardiac surgery via median sternotomy with atrial fibrillation or a Congestive Heart Failure, Hypertension, Age > 75 Years, Diabetes Mellitus, Stroke score greater than 2 were eligible for concomitant AtriClip (Atricure Inc, Westchester, Ohio) device insertion. Device insertion (35, 40, 45, and 50 mm) was performed at any point after sternotomy on or off cardiopulmonary bypass. Safety was assessed at 30 days, and efficacy of left atrial appendage exclusion was assessed at operation (by transesophageal echocardiography) and 3-month follow-up (by computed tomography angiography or transesophageal echocardiography).

RESULTS

A total of 71 patients (mean age, 73 years) undergoing open cardiac surgery at 7 US centers were enrolled in the study. The left atrial appendage in 1 patient was too small and did not meet eligibility criteria; the remaining 70 patients had successful placement of an AtriClip device. Intraprocedural successful left atrial appendage exclusion was confirmed in 67 of 70 patients (95.7%). Although significant adverse events occurred in 34 of 70 patients (48.6%), there were no adverse events related to the device and no perioperative mortality. At 3-month follow-up, 1 patient died and 65 of 70 patients (92.9%) were available for assessment. Of the patients who underwent imaging, 60 of 61 patients (98.4%) had successful left atrial appendage exclusion by computed tomography angiography or transesophageal echocardiography imaging.

CONCLUSIONS

In this small study, safe and atraumatic exclusion of the left atrial appendage can be performed during open cardiac surgery with the AtriClip device with greater than 95% success and appears to be durable in the short term by imaging. Long-term studies are needed to evaluate the efficacy in the prevention of stroke.

Pericardial Free Patch Grafting as a Rescue Technique in Surgical Management of Right Atrial HSA

A 7 yr old, neutered female vizsla underwent an exploratory thoracotomy after diagnosis of recurrent hemorrhagic pericardial effusion and a right auricular mass. Staging tests were negative for metastasis. The patient underwent a right, fourth intercostal thoracotomy, subtotal pericardectomy, right auricular mass excision, and pericardial free patch graft. The patient experienced blood loss during surgery, which required a packed red blood cell transfusion. The patient experienced transient arrhythmias postoperatively, but was discharged from the hospital 48 hr later. Histopathologic diagnosis of the mass was hemangiosarcoma. The patient was treated with carboplatin single-agent chemotherapy and palliative radiation therapy. The patient died at home, presumably from metastatic disease 260 days postoperatively. Surgical mass removal or debulking along with pericardial free patch grafting may be considered as palliative treatment options for dogs diagnosed with right auricular masses. In this case report, other techniques failed to repair the defect in the heart and a free patch graft offered a good rescue procedure with a favorable outcome without the need for inflow and outflow occlusion when used in conjunction with adjunctive therapies.

Management of the left atrial appendage

Surgical and interventional exclusion left atrial appendage (LAA) are becoming important alternatives to oral anticoagulation for stroke prevention in the setting of atrial fibrillation. Herein we present the different approaches (endocardial vs. epicardial) to LAA occlusion. Each approach is depicted in detail and relevant literature is briefly presented.

Left atrial appendage clip occlusion: early clinical results

OBJECTIVE

Atrial fibrillation puts patients at significant risk for embolic stroke originating from the left atrial appendage. Few means are available for safe, effective, and durable left atrial appendage occlusion. A new clip device was evaluated with regard to safety and effectiveness for epicardial left atrial appendage occlusion.

METHODS

Patients with atrial fibrillation undergoing elective cardiac surgery through a median sternotomy were enrolled for concomitant epicardial clip placement. Early postoperative and 3-month follow-up computed tomography studies were used to assess clip stability and left atrial appendage perfusion.

RESULTS

From September 2007 to December 2008, 34 patients underwent successful clip placement. No device-related complications occurred. Operative mortality was 8.8% and not study or device related. Deployment was rapid, and left atrial appendage occlusion was confirmed by intraoperative transesophageal echocardiography in all patients. In addition to excellent clinical outcomes (no stroke/transient ischemic attack), serial computed tomography demonstrated stable clip location and appendage perfusion at 3 months in all patients.

CONCLUSION

Safe, effective, and durable left atrial appendage occlusion can easily be achieved with this new clip. Further trials are necessary to evaluate the role of the left atrial appendage occlusion in stroke prevention.