Recanalization of the left atrial appendage demonstrated by transesophageal echocardiography

The completeness of the left atrial appendage amputation during routine cardiac surgery

BACKGROUND

Left atrial appendage (LAA) is the origin of most heart thrombi which can lead to stroke or other cerebrovascular event in patients with non-valvular atrial fibrillation (AF). This study aimed to prove safety and low complication rate of surgical LAA amputation using cut and sew technique with control of its effectiveness.

METHODS

303 patients who have undergone selective LAA amputation were enrolled in the study in a period from 10/17 to 08/20. The LAA amputation was performed concomitant to routine cardiac surgery on cardiopulmonary bypass with cardiac arrest with or without previous history of AF. The operative and clinical data were evaluated. Extent of LAA amputation was examined intraoperatively by transoesophageal echocardiography (TEE). Six months in follow up, the patients were controlled regarding clinical status and episodes of strokes.

RESULTS

Average age of study population was 69.9 ± 19.2 and 81.9% of patients were male. In only three patients was residual stump after LAA amputation larger than 1 cm with average stump size 0.28 ± 0.34 cm. 3 patients (1%) developed postoperative bleeding. Postoperatively 77 (25.4%) patients developed postoperative AF (POAF), of which 29 (9.6%) still had AF at discharge. On 6 months follow up only 5 patients had NYHA class III and 1 NYHA class IV. Seven patients reported with leg oedema and no patient experienced any cerebrovascular event in early postoperative follow up.

CONCLUSION

LAA amputation can be performed safely and completely leaving minimal to no LAA residual stump.

Left Atrial Appendage Ostial Stenosis: A Case Report and Literature Review

Patient: Female, 34-year-old

Final Diagnosis: Left atrial appendage ostial stenosis

Symptoms: No symptoms

Medication:—

Clinical Procedure: —

Specialty: Cardiology

Surgical techniques for left atrial appendage exclusion

The increasing prevalence of atrial fibrillation with the aging population and its associated major morbidity and mortality due to thromboembolic stroke have resulted in intensive research on stroke prevention or stroke risk reduction strategies. Several surgical techniques for left atrial appendage (LAA) occlusion have evolved over the past decades. Surgeons have been using different techniques leading to highly variable and, in particular, poor data on outcomes. LAA closure is performed either as a concomitant procedure during open-heart surgery or as a stand-alone surgical procedure as part of minimally invasive (mini-thoracotomy or thoracoscopy) arrhythmia surgery. Data on the safety and feasibility of surgical LAA occlusion are derived mainly from nonrandomized case series, observational and cohort studies, or registries with mostly inconclusive and conflicting results. Increased awareness of the high failure rates in attaining complete LAA occlusion, thus avoiding poor surgical techniques (e. g., simple suture ligation, endocardial suturing etc.), and the availability of newer devices (e. g., AtriClip device) have recently led to improved surgical results in the literature. If further validated in large-scale studies, these recent promising developments in the field of surgical LAA treatment seem to offer alternatives for patients ineligible for oral anticoagulation therapy with vitamin K antagonists or newer non-vitamin-K-dependent oral anticoagulants.

Complete Obliteration of the Left Atrial Appendage: An Analysis of Epicardial Excision and Novel Pericardial Patch Exclusion

OBJECTIVE

Conventional epicardial excision is believed to be the most effective method of surgically obliterating the left atrial appendage (LAA), although incomplete resection and residual LAA volume may undermine its effectiveness. We sought to compare the impact of conventional epicardial excision with a novel LAA pericardial patch exclusion on residual LAA volume.

METHODS

We performed LAA obliteration using pericardial patch exclusion, followed by conventional epicardial excision, in 27 cadaveric hearts. After each procedure, residual LAA volume was measured by two different techniques and compared with baseline volume. There was no difference in baseline LAA volume between each procedure.

RESULTS

Procedural success was achieved in all hearts. Conventional epicardial excision left a residual LAA volume of 0.95 mL (24%), as compared with pericardial patch exclusion, which left a residual volume of 0.17 mL (4%, P = 0.0001). Further analysis of fixed and fresh hearts showed that reduction of LAA volume was more pronounced in the fresh hearts, suggesting effectiveness in live patients. Neither technique resulted in any significant change in the endocardial shape of the LAA orifice or injury to the circumflex artery.

CONCLUSIONS

Conventional epicardial excision of the LAA results in significantly more residual LAA volume, which may have important implications in persistent stroke risk. Pericardial patch exclusion seems to achieve near-total elimination of the LAA and may be a superior surgical option.

Surgical Treatment of Atrial Fibrillation

Atrial fibrillation (AF) is the most common chronic arrhythmia in the adult population. Ablation lines have largely replaced the historical and challenging cut and sew techniques. Surgical ablation of AF is commonly performed in cases with other indications for cardiac surgery and less commonly as a stand-alone therapy. Pulmonary vein isolation is the cornerstone of this procedure. Extended left atrial ablation lines may increase efficacy in cases with longstanding persistent or permanent AF. Additional efficacy by adding right atrial ablation is controversial but is often performed in cases undergoing right atrial or atrial septal surgery. Left atrial volume reduction is recommended in cases with large left atria and AF undergoing another cardiac surgery. Arrhythmia recurrence is not uncommon after surgical ablation of AF and varies among studies due to heterogeneity in patient population, lesion set and endpoints. Freedom from AF recurrence was 65-87% at 12 months and 58-70% at 2 years follow-up. Long-term monitoring is recommended due to an increased prevalence of asymptomatic recurrences. The strongest predictors of AF recurrence are longstanding or persistent AF and a large left atrium. The most common mechanisms of recurrence are pulmonary vein reconnection, nonpulmonary vein triggers, and gaps in the ablation lines. About 20% of atrial tachyarrhythmia recurrences are atrial flutter or atrial tachycardia. There are not enough data in the surgical literature to support withdrawal of anticoagulation after surgical AF ablation. Patients selected for stand-alone surgical ablation usually have low risk profiles and low postoperative mortality rates (0.2%).

Clinical Results with Percutaneous Left Atrial Appendage Occlusion

Closure of the left atrial appendage (LAA) in patients with non-valvular atrial fibrillation is associated with reduction in embolic events. There is an initial hazard associated with closure methodologies; once successful closure is achieved, the results appear to be superior to those of anticoagulation. The evidence base is largely limited to the safety and efficacy of LAA occlusion in patients who are candidates for anticoagulation as well, and the risk/benefit ratio of competing closure technologies has not been determined. LAA occlusion plus antiplatelet therapy seems to have an acceptable therapeutic and safety profile.

Left Atrial Appendage Closure with Transcatheter-Delivered Devices

Left atrial appendage (LAA) closure with transcatheter-delivered devices is an evolving story of compelling randomized data and the potential to dramatically reduce the incidence of stroke and improve the quality of life among patients with atrial fibrillation. Oral anticoagulation is the standard of care for stroke prevention in atrial fibrillation but falls short of providing an adequate solution to this common threat when considered from efficacy and safety perspectives. The robust series of Watchman device trials has demonstrated the Watchman device to provide stroke prevention efficacy similar to that of warfarin and by extension provides proof of concept of LAA closure.

Nonpharmacologic stroke prevention in atrial fibrillation

Atrial fibrillation is associated with significant mortality and morbidity. The burden of morbidity in atrial fibrillation is mostly due to stroke, one of the major causes of death and the leading cause of long-term disability. Although highly effective in prevention of thromboembolic stroke, several factors limit utilization of chronic oral anticoagulation therapy. Eradication of atrial fibrillation and restoration of effective atrial contraction by surgical methods, or recently, by percutaneous catheter ablation methods, are two attractive approaches for stroke prophylaxis. Surgical exclusion of the left atrial appendage has generated considerable interest in the past decades and it is now performed routinely during mitral valve surgery in many centers. Recently, minimally invasive and percutaneous methods for the exclusion of left atrial appendage have been introduced. Currently, these approaches are being evaluated in ongoing trials. This review will discuss the current status of nonpharmacologic methods in the prevention of stroke in atrial fibrillation.

Percutaneous Closure of the Left Atrial Appendage

This article reviews the published evidence on stroke prevention with percutaneous closure of the left atrial appendage and provides comparative insight into the various left atrial appendage closure devices currently in development.

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.

Success of surgical left atrial appendage closure: assessment by transesophageal echocardiography

OBJECTIVES

We sought to determine which surgical technique of left atrial appendage (LAA) closure is most successful by assessing them with transesophageal echocardiography (TEE).

BACKGROUND

Atrial fibrillation is a risk factor for stroke, with 90% of clots occurring in the LAA. Several surgical techniques of LAA closure are used to theoretically reduce the stroke risk, with varying success rates.

METHODS

A total of 137 of 2,546 patients who underwent surgical LAA closure from 1993 to 2004 had a TEE after surgery. Techniques consisted of either excision or exclusion by sutures or stapling. The TEE measurements included color Doppler flow in the LAA and interrogation for thrombus. Patent LAA, remnant LAA (residual stump >1 cm), or excluded LAA with persistent flow into the LAA were identified as unsuccessful closure.

RESULTS

Of the 137 patients, 52 (38%) underwent excision and 85 (62%) underwent exclusion (73 suture and 12 stapler). Only 55 of 137 (40%) of closures were successful. Successful LAA closure occurred more often with excision (73%) than suture exclusion (23%) and stapler exclusion (0%) (p < 0.001). We found LAA thrombus to be present in 28 of 68 patients (41%) with unsuccessful LAA exclusion versus none with excision. At time of TEE, 6 patients with successful LAA closure (11%) and 12 with unsuccessful closure (15%) had evidence of stroke/transient ischemic attack (p = 0.61).

CONCLUSIONS

There is a high occurrence of unsuccessful surgical LAA closure. Of the various techniques, excision appears to be the most successful.

Surgical ablation of atrial fibrillation: the Columbia Presbyterian experience

BACKGROUND

The Maze III procedure is an effective surgical treatment for atrial fibrillation (AF). However, it is not widely applied due to its complexity, increased operative times, and the risk of bleeding. Various energy sources have been introduced to simplify the traditional "cut and sew" approach.

METHODS

This study involves patients undergoing surgical atrial fibrillation ablation (SAFA) at a single institution from 1999 to 2005. Type of concomitant procedures, preoperative clinical characteristics, and chronicity of AF were evaluated in overall patient population. Parameters including surgical approach, lesion pattern, and energy source used were collected intraoperatively. Clinical outcomes examined were postoperative rhythm success, stroke, early mortality, and long-term survival.

RESULTS

Three hundred thirty-nine patients were identified. Three hundred twenty-eight (96.8%) patients had associated cardiac disease and underwent concomitant procedures; 75.8% of patients had persistent AF. Energy sources used were microwave (49.8%), radiofrequency (42.2%), and laser (8.0%). In 41.9% of cases a pulmonary vein encircling lesion was the only lesion created. Combination lesion sets were performed in the remaining cases. Rhythm success rates at 3, 6, 12, and 24 months were 74.1%, 68.2%, 74.5%, and 71.1%, respectively. Patients who underwent surgical removal of left atrial appendage by means of stapling or simple excision had no early postoperative stroke. Early mortality was 4.9%. Postoperative survival rates at 1, 3, and 5 years were 89.6%, 83.1%, and 78.0%.

CONCLUSIONS

Surgical ablation of atrial fibrillation is a safe and effective procedure in restoring sinus rhythm with excellent postoperative survival rates. Further advancements in the field will eventually result in minimally invasive procedures with higher success rates.

Impact of maze and concomitant mitral valve surgery on clinical outcomes

We evaluated the usefulness of the maze procedure among patients with atrial fibrillation undergoing mitral valve surgery. Seven matched-controlled and four randomized trials were identified from Medline English language papers (1995 to 2005). After 2 to 8 years of follow-up in matched-controlled studies, odds ratio and 95% confidence interval (CI) for atrial fibrillation free, embolic events free, and long-term survival for those treated with maze were 12.51 (95% CI: 9.18 to 17.03), 9.35 (95% CI: 5.11 to 17.13), and 2.27 (95% CI: 1.21 to 4.27), respectively. Correspondingly, after 1 to 1.5 years of follow-up in randomized trials, they were 9.01 (95% CI: 4.21 to 19.3), 5.19 (95% CI: 0.50 to 53.6), and 0.49 (95% CI: 0.12 to 1.93), respectively. The addition of the maze procedure to mitral valve surgery was more likely to maintain patients in sinus rhythm and may lower embolic events, including stroke, but did not necessarily improve long-term survival.

Surgical Closure of the Left Atrial Appendage – A Beneficial Procedure?

BACKGROUND

Closure of the fibrillating left atrial appendage (LAA) has been recommended during valve surgery to decrease the risk of arterial embolism. However, patients undergoing surgical LAA closure have not systematically been reevaluated for complete LAA obliteration.

METHODS AND RESULTS

During a 12-month period, we studied 6 consecutive patients with paroxysmal (n = 3) or permanent (n = 3) atrial fibrillation who underwent surgical LAA closure at the time of valve surgery. Transesophageal echocardiography (TEE) performed 23-159 days (mean 51) postoperatively demonstrated complete LAA closure in only 1 patient. In 5 patients, incomplete LAA closure was found due to disruption of the closure line. The size of the residual LAA orifice ranged from 3 to 20 mm. There was a high flow velocity at the LAA orifice (0.33-2.2 m/s), whereas flow in the LAA body was low (<0.2 m/s). Spontaneous echocardiographic contrast (SEC) in the LAA had newly developed (n = 3) or was much more intense than preoperatively (n = 2). Despite therapeutic anticoagulation 2 patients showed a LAA thrombus which had not been present on the preoperative TEE, and 1 patient with SEC suffered a stroke 4 weeks after attempted LAA closure.

CONCLUSION

Surgical LAA closure was incomplete in most patients, resulting in blood stagnation and an increased likelihood of clot formation. Incomplete surgical LAA closure, therefore, may promote rather than reduce the risk of stroke. Intraoperative TEE is mandatory to verify complete LAA obliteration.

Nonobstructive membranes of the left atrial appendage cavity: report of three cases

A membranous structure causing functional stenosis at the mouth of the left atrial appendage (LAA) has been reported. In this study we describe the presence of nonobstructive membranes traversing the cavity of the LAA found incidentally on transesophageal echocardiography (TEE).

Thromboembolus from a ligated left atrial appendage

The left atrial appendage of patients with mitral valve disease is commonly a source of thromboembolus and is often ligated during mitral valve surgery to diminish this risk. However, ligation is often incomplete. We describe a patient with a stroke whose only source of embolus was an incompletely ligated left atrial appendage. Attempts to exclude the left atrial appendage from the arterial circulation by suture ligation may not decrease the risk of thromboemboli and instead may increase such risk.

Surgical left atrial appendage ligation is frequently incomplete: a transesophageal echocardiograhic study

OBJECTIVES

This study sought to determine the incidence of incomplete ligation of the left atrial appendage (LAA) during mitral valve surgery.

BACKGROUND

Ligation of the LAA to prevent future thromboembolic events is commonly performed during mitral surgery. However, success in completely excluding the appendage from the circulation has never been systematically assessed.

METHODS

Using transesophageal Doppler echocardiography, we studied 50 patients who underwent mitral valve surgery and ligation of the LAA. Thirty patients were studied immediately postoperative, and 20 patients were studied 6 days to 13 years after surgery. Incomplete ligation was detected by demonstrating a color jet traversing the separation between the left atrial body and appendage.

RESULTS

Transesophageal echocardiography detected incomplete LAA ligation in 18 of 50 (36%) patients. The incidence of incomplete ligation was not significantly different between patients studied immediately postoperative and patients studied at various times after surgery. Type of mitral surgery (repair vs. replacement), operative approach (sternotomy vs. port access), left atrial size or degree of mitral regurgitation did not significantly correlate with the incidence of incomplete appendage ligation. However, the power to detect a significant difference in left atrial size was only 64%. Spontaneous echo contrast or thrombus was identified within appendages in 9 of 18 (50%) patients with incomplete ligation, while 4 of these 18 (22%) patients had thromboembolic events.

CONCLUSIONS

Surgical LAA ligation is frequently incomplete. The similar incidence of incomplete ligation detected immediately postoperative and at various times thereafter suggest that this results from an intraoperative phenomenon rather than from gradual dehiscence of sutures over years. The incidence of incomplete left atrial ligation was unrelated to type of surgery, surgical approach, left atrial size or degree of mitral regurgitation. Residual communication between the incompletely ligated appendage and the left atrial body may produce a milieu of stagnant blood flow within the appendage and be a potential mechanism for embolic events.

Left atrial appendage stenosis

Narrowing at the mouth of the left atrial appendage has been reported after partial surgical ligation of the appendage. This report describes a patient, without prior cardiac surgery, who had an anatomic narrowing at the opening of the left atrial appendage demonstrated by 2-dimensional, Doppler, and color Doppler echocardiography.

Large gradient across a partially ligated left atrial appendage

The left atrial appendage is frequently ligated during mitral valve surgery to decrease the future risk of embolic events. The postoperative detection of a partially occluded left atrial appendage has previously been reported with the use of transesophageal echocardiography. We describe an unusual case in which Doppler echocardiography demonstrated a remarkably high-velocity jet emanating from a partially ligated left atrial appendage.