Left atrial appendage exclusion and the risk of thromboembolic events following mitral valve surgery

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.

Management of atrial fibrillation in rheumatic heart disease

Rheumatic heart disease (RHD) is the underlying cause of a significant proportion of atrial fibrillation (AF) in the low- and middle-income countries, while nonvalvular AF is the most common cause of AF in high-income countries. RHD is also common among African Americans, migrants, and the indigenous population of high-income countries. The onset of AF in RHD patients is a clinical marker of worse outcomes and is associated with significant morbidity and mortality. Despite RHD being a major cause of morbidity and mortality in the young in many parts of the world, it is often neglected by policymakers, the media, and even the medical fraternity. Stroke risk assessment using various risk scores has not been systematically evaluated in rheumatic AF patients. Rate control may not be ideal for symptom control in rheumatic AF patients considering the young age and an active lifestyle. There is limited information regarding the nonpharmacological management of rheumatic AF. The current management guidelines based on nonvalvular AF do not apply to rheumatic AF patients who are often younger, are women, and have fewer comorbidities. This review critically looks at specific areas such as stroke prevention with reference to direct oral anticoagulants, cardioversion, rate and rhythm control strategies, and the role of nonpharmacological methods in rheumatic AF management. Future recommendations must be cognizant of local health care systems and resourcing considering the geographic distribution of the disease.

Routine left atrial appendage occlusion in patients undergoing cardiac surgery: a narrative review

PURPOSE OF REVIEW

New evidence suggests a greater prevalence of protracted postoperative atrial fibrillation (POAF) than previously recognized. The left atrial appendage (LAA) is the most common source of embolism in patients with nonvalvular atrial fibrillation. In this review, we ask whether there is evidence to support routine LAA occlusion (LAAO) in patients without preexisting atrial fibrillation undergoing cardiac surgery.

RECENT FINDINGS

Overall, available studies are small, inconsistent and have varying proportions of patients with and without preexisting atrial fibrillation. There is considerable discrepancy with respect to the efficacy of LAAO in reducing the risk of POAF-related stroke. Only one study reported a lower rate of stroke in the LAAO group compared with no LAAO. Two studies included a subgroup analysis of patients that developed POAF and report a significantly higher rate of stroke in patients that developed POAF and did not undergo LAAO. There are three clinical trials ongoing that are investigating prophylactic LAAO in patients undergoing cardiac surgery: ATLAS, LAA-CLOSURE and LAACS-2.

SUMMARY

There is currently insufficient evidence to recommend routine addition of LAAO to lower the risk of postoperative stroke. Ongoing clinical trials will provide important insight into the role of routine LAAO in all patients undergoing cardiac surgery.

The 2020 Canadian Cardiovascular Society/Canadian Heart Rhythm Society Comprehensive Guidelines for the Management of Atrial Fibrillation

The Canadian Cardiovascular Society (CCS) atrial fibrillation (AF) guidelines program was developed to aid clinicians in the management of these complex patients, as well as to provide direction to policy makers and health care systems regarding related issues. The most recent comprehensive CCS AF guidelines update was published in 2010. Since then, periodic updates were published dealing with rapidly changing areas. However, since 2010 a large number of developments had accumulated in a wide range of areas, motivating the committee to complete a thorough guideline review. The 2020 iteration of the CCS AF guidelines represents a comprehensive renewal that integrates, updates, and replaces the past decade of guidelines, recommendations, and practical tips. It is intended to be used by practicing clinicians across all disciplines who care for patients with AF. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) system was used to evaluate recommendation strength and the quality of evidence. Areas of focus include: AF classification and definitions, epidemiology, pathophysiology, clinical evaluation, screening and opportunistic AF detection, detection and management of modifiable risk factors, integrated approach to AF management, stroke prevention, arrhythmia management, sex differences, and AF in special populations. Extensive use is made of tables and figures to synthesize important material and present key concepts. This document should be an important aid for knowledge translation and a tool to help improve clinical management of this important and challenging arrhythmia.

Surgical left atrial appendage occlusion in patients with atrial fibrillation undergoing mechanical heart valve replacement

BACKGROUND

Surgical left atrial appendage occlusion (SLAAO) may be associated with a lower risk of thromboembolism in patients with atrial fibrillation undergoing cardiac surgery. However, evidence regarding the effectiveness of SLAAO in patients undergoing mechanical heart valve replacement (MHVR) is lacking. Therefore, we aimed to evaluate the association between SLAAO and the cardiovascular outcomes in patients with atrial fibrillation undergoing MHVR.

METHODS

We retrospectively analyzed data for 497 patients with atrial fibrillation; 27.6% of the patients underwent SLAAO, and the remainder of the patients did not (No-SLAAO group). The primary outcome was a composite of ischemic stroke, systemic embolism, and all-cause mortality. Cumulative event-free survival rates were estimated using Kaplan-Meier curves, and we performed multivariate Cox analyses to evaluate the association between SLAAO and outcomes. We used one-to-one propensity score matching to balance patients' baseline characteristics, and analyzed 120 matching pairs.

RESULTS

Five patients died within 30 days postoperatively, and there were no significant differences between the two groups regarding in-hospital complications (all P > 0.05). After a median follow-up of 14 months, 14 primary events occurred. Kaplan-Meier curves showed no difference in the cumulative incidence of freedom from the primary outcome (log-rank P = 0.830), hemorrhagic events (log-rank P = 0.870), and the secondary outcome (log-rank P = 0.730), between the two groups. Multivariable Cox proportional hazards regression analysis showed no association between SLAAO and any outcome (all P > 0.05). After propensity score matching, cardiopulmonary bypass time and aortic cross-clamp time, and the postoperative length of stay were significantly longer in the SLAAO group (all P < 0.05); results were similar to the unadjusted analyses.

CONCLUSIONS

Concomitant SLAAO and MHVR was associated with longer length of stay, and cardiopulmonary bypass time and aortic cross-clamp time, but was not associated with additional protective effects against thromboembolic events and mortality during the 14-month follow-up.

Meta-Analysis Evaluating Outcomes of Surgical Left Atrial Appendage Occlusion During Cardiac Surgery

Surgical left atrial appendage occlusion (S-LAAO) has become a common procedure performed in patients undergoing cardiac surgery; however, evidence to support this procedure remains inconclusive. This meta-analysis aims to assess the efficacy of S-LAAO in terms of ischemic stroke, postoperative atrial fibrillation, and all-cause mortality. A thorough literature review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. We identified 10 relevant studies for our meta-analysis. It included 6,779 patients who underwent S-LAAO and 6,573 who did not undergo LAAO. In terms of ischemic stroke, the S-LAAO cohort had a lower events (pooled odds ratio [OR] 0.655 (0.518 to 0.829), p = 0.0004) compared with the non-LAAO cohort. S-LAAO cohort also had lower events of all-cause mortality (pooled OR 0.74 (95% confidence interval 0.55 to 0.99), p = 0.0408) when compared with the non-LAAO cohort. In regards to postoperative atrial fibrillation, there was no difference between the 2 groups (pooled OR 1.29 (95% confidence interval 0.81 to 2.06), p = 0.2752). In conclusion, S-LAAO was associated with lower events of ischemic stroke or systemic embolism and all-cause mortality when compared to the non-LAAO group.

Does Left Atrial Appendage Amputation During Routine Cardiac Surgery Reduce Future Atrial Fibrillation and Stroke?

Purpose of Review

Stroke is the most feared complication of atrial fibrillation. To prevent stroke, left atrial appendage exclusion has been targeted, as it is the prevalent site for formation of heart thrombi during atrial fibrillation.

We review the historic development of methods for exclusion of the left atrial appendage and the evidence to support its amputation during routine cardiac surgery.

Recent Findings

Evidence is not yet sufficient to routinely recommend left atrial exclusion during heart surgery, despite a high prevalence of postoperative atrial fibrillation. Observational studies indicate that electrical isolation of scarring from clip or suture techniques reduces the arrhythmogenic substrate.

Summary

Randomized studies comparing different methods of closure of the left atrial appendage before amputation do not exist. Such studies are therefore warranted, as well as studies that can elucidate whether amputation is superior to leaving the left atrial appendage stump. Potentially, thrombogenic remaining pouch after closure should be addressed.

Evaluation of anticoagulation use and subsequent stroke in patients with atrial fibrillation after empiric surgical left atrial appendage closure: A retrospective case-control study

BACKGROUND

Surgical exclusion of the left atrial appendage (LAA) can be performed at the time of cardiac operation as a potential modality to decrease cardioembolic risk attributable to atrial fibrillation (AF), but it remains unclear if this decreases stroke incidence. Furthermore, it is not known whether LAA exclusion impacts the decision to discontinue anticoagulation impacting subsequent stroke risk.

HYPOTHESIS

LAA exclusion does not significantly alter subsequent anticoagulation use or stroke incidence.

METHODS

We studied 124 patients from Olmsted County with prior history of AF who underwent cardiac surgery at our institution between 1993 and 2015. Patients were divided into two groups on the basis of LAA exclusion and matched (1:1) according to 16 pretreatment variables using propensity scores obtained from a logistic regression model. Outcome data collected through chart review for survival, stroke, and the presence and duration of anticoagulation were compared between groups.

RESULTS

The proportion of patients receiving anticoagulation at discharge and at 5 years was not significantly different between patients who underwent LAA exclusion and those who did not; 90% vs 81%, P = 0.156, 48% vs 49%, P = 0.722, respectively. On Kaplan-Meier analysis there were no significant differences in time free from stroke between cases and controls. Patients discharged on oral anticoagulation (OAC) had significantly lower risk of stroke (HR = 0.19, 95% confidence interval [CI] = 0.06-0.59, P = 0.004), independent of whether LAA closure was used.

CONCLUSION

LAA exclusion did not appear to reduce early or late stroke. Only OAC was associated with a reduction in stroke risk, underscoring the need for continued anticoagulation in high-risk patients.

Impact of Left Atrial Appendage Exclusion on Cardiovascular Outcomes in Patients With Atrial Fibrillation Undergoing Coronary Artery Bypass Grafting (From the National Inpatient Sample Database)

Left atrial appendage (LAA) exclusion is performed by some surgeons in patients with atrial fibrillation (AF) who undergo coronary artery bypass grafting (CABG). However, the available evidence regarding the efficacy and safety of this procedure remains mixed. We queried the Nationwide Inpatient Survey Database for the 10-year period from 2004 to 2013. Using International Classification of Diseases, Ninth Edition, Clinical Modification diagnosis codes, we identified patients who had a diagnosis of AF and underwent a primary procedure of CABG with or without LAA exclusion. We then performed a 1:5 matching based on the CHA₂DS₂VASc score between patients who got LAA exclusion and those who did not (control group). The primary outcome was the incidence of in-hospital cerebrovascular events, whereas the secondary outcomes included in-hospital bleeding events, pericardial effusion, cardiac tamponade, postoperative shock, and mortality. Our analysis included a total of 15,114 patients. Patients who underwent LAA exclusion had significantly less incidence of cerebrovascular events (2.0% vs 3.1%, p = 0.002). However, LAA exclusion group had higher incidences of bleeding events (36.4% vs 21.3%, p <0.001), pericardial effusion (2.7% vs 1.2%, p <0.001), cardiac tamponade (0.6% vs 0.2%, p <0.001), and postoperative shock (1.2% vs 0.4%, p <0.001). LAA exclusion was associated with higher in-hospital mortality (1.6% vs 0.3%, p <0.001). Multivariate regression analysis showed that LAA exclusion was significantly associated with lower cerebrovascular accident events and higher in-hospital mortality. In conclusion, LAA exclusion in patients with AF undergoing CABG might be associated with a lower incidence of in-hospital cerebrovascular events. This benefit is offset by a higher incidence of higher bleeding events, pericardial effusion, cardiac tamponade, postoperative shock, and in-hospital mortality.

Cardiovascular Outcomes With Surgical Left Atrial Appendage Exclusion in Patients With Atrial Fibrillation Who Underwent Valvular Heart Surgery (from the National Inpatient Sample Database)

Left atrial appendage (LAA) exclusion is a commonly performed procedure to reduce the embolic events in patients with atrial fibrillation (AF) who underwent cardiac surgeries. Our study aimed to evaluate the in-hospital outcomes of LAA exclusion in patients with AF who underwent valvular heart surgeries. We queried the Nationwide Inpatient Sample Database from 1998 to 2013 for patients with the International Classification of Diseases, Ninth Edition, Clinical Modification, diagnosis codes for AF and underwent any valvular heart surgery. We then performed a case-control matching based on the CHA₂DS₂VASc score for those who underwent LAA exclusion versus those who did not. Primary outcome was the incidence of in-hospital cerebrovascular events, whereas the secondary outcomes included all-cause mortality, length of hospital stay, and bleeding. Our analysis included 1,304 patients. Patients who underwent LAA exclusion had significantly less incidence of cerebrovascular events (2.5% vs 4.6%, p = 0.04), in-hospital death (1.5% vs 4.9%, p = 0.001), and shorter hospital stay (10.5 vs 12.9 days, p <0.01). The LAA exclusion cohort had more incidence of pericardial effusion (1.3% vs 0.5%, p = 0.04) but no difference in bleeding events (p = 0.55). In conclusion, in patients with AF who underwent valvular surgeries, LAA exclusion may be associated with lower in-hospital cerebrovascular events and mortality and shorter hospital stay.

Impact of Left Atrial Appendage Closure During Cardiac Surgery on the Occurrence of Early Postoperative Atrial Fibrillation, Stroke, and Mortality: A Propensity Score-Matched Analysis of 10 633 Patients

BACKGROUND

Prophylactic exclusion of the left atrial appendage (LAA) is often performed during cardiac surgery ostensibly to reduce the risk of stroke. However, the clinical impact of LAA closure in humans remains inconclusive.

METHODS

Of 10 633 adults who underwent coronary artery bypass grafting and valve surgery between January 2000 and December 2005, 9792 patients with complete baseline characteristics, surgery procedure, and follow-up data were included in this analysis. A propensity score-matching analysis based on 28 pretreatment covariates was performed and 461 matching pairs were derived and analyzed to estimate the association of LAA closure with early postoperative atrial fibrillation (POAF) (atrial fibrillation ≤30 days of surgery), ischemic stroke, and mortality.

RESULTS

In the propensity-matched cohort, the overall incidence of POAF was 53.9%. In this group, the rate of early POAF among the patients who underwent LAA closure was 68.6% versus 31.9% for those who did not undergo the procedure (P<0.001). LAA closure was independently associated with an increased risk of early POAF (adjusted odds ratio, 3.88; 95% confidence interval, 2.89-5.20), but did not significantly influence the risk of stroke (adjusted hazard ratio, 1.07; 95% confidence interval, 0.72-1.58) or mortality (adjusted hazard ratio, 0.92; 95% confidence interval, 0.75-1.13).

CONCLUSIONS

After adjustment for treatment allocation bias, LAA closure during routine cardiac surgery was significantly associated with an increased risk of early POAF, but it did not influence the risk of stroke or mortality. It remains uncertain whether prophylactic exclusion of the LAA is warranted for stroke prevention during non-atrial fibrillation-related cardiac surgery.

Percutaneous balloon mitral valvuloplasty and closure of the left atrial appendage: Synergy of two procedures in one percutaneous intervention

Mitral stenosis (MS) is frequently associated with the development of atrial fibrillation (AF) as a consequence of hemodynamic and inflammatory changes in the left atrium. Both conditions predispose to thrombus formation, with frequent involvement of the left atrial appendage (LAA), and consequent increase in the incidence of systemic thromboembolic events. Percutaneous mitral valvuloplasty (PMV) reduces the risk of thromboembolism in patients with significant mitral stenosis. Percutaneous LAA closure is also associated with a reduction in thromboembolic risk in patients with AF, but there are no data regarding the use of this technique in patients with significant mitral valve disease. We report the case of a 57-year-old-woman with significant MS and permanent AF, in New York Heart Association functional class II, who despite adequate oral anticoagulation with acenocoumarol, presented several clinical episodes of systemic thromboembolism in the last four years. It was decided to perform a combined percutaneous procedure, including both PMV and percutaneous LAA closure with the Amplatzer Cardiac Plug device. No significant acute complications occurred and the patient was discharged on indefinite treatment with acenocoumarol associated with aspirin 100 mg/d for three months. After a one-year follow-up, there have been no new embolic episodes or other complications.

Surgical perspectives in the management of atrial fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia and a huge public health burden associated with significant morbidity and mortality. For decades an increasing number of patients have undergone surgical treatment of AF, mainly during concomitant cardiac surgery. This has sparked a drive for conducting further studies and researching this field. With the cornerstone Cox-Maze III “cut and sew” procedure being technically challenging, the focus in current literature has turned towards less invasive techniques. The introduction of ablative devices has revolutionised the surgical management of AF, moving away from the traditional surgical lesions. The hybrid procedure, a combination of catheter and surgical ablation is another promising new technique aiming to improve outcomes. Despite the increasing number of studies looking at various aspects of the surgical management of AF, the literature would benefit from more uniformly conducted randomised control trials.

Variations in Anticoagulation Practices Following the Maze Procedure

The current real-world anticoagulation practices following left atrial appendectomy in the context of the Maze procedure are unknown. This is a cohort study of all patients who underwent the Maze procedure with amputation of the left atrial appendage from June 2005 to November 2012. Data was prospectively collected at regular intervals with an interview and Holter monitoring. All patients received anticoagulation for 3 months. Those then kept on anticoagulation and those for whom anticoagulation was stopped were compared in terms of death, bleeding and incidence of stroke. In total, there were 113 patients, of whom 66 were treated with anticoagulation (Group A) and 47 were not (Group B). There were no significant baseline differences between the two groups, including the presence of atrial fibrillation (A:19.7%, B:10.6%, p=0.30), CHADS2 score (A:1.41±1.05, B:1.15±1.08, p=0.19), and left atrial size (A:48.3±7.1mm, B:47.6±7.8 mm, p=0.57). There were 275 patient-years of follow-up, with an average of 2.43 years per patient. Only two patients experienced strokes, both in Group A (p=0.27). Of the 5 bleeding events, 4 occurred in the first 3 months while on anticoagulation and the remaining event occurred in Group A at 3 years post-operatively (p=0.10). No standardized approach to anticoagulation after the Maze procedure is apparent in real-world practice in an urban Canadian setting. Patients who undergo the Maze procedure with amputation of the left atrial appendage are at a low risk of stroke, but the optimal anticoagulation strategy requires further investigation.

Efficacy of Oral Anticoagulation in Stroke Prevention among Sinus-Rhythm Patients Who Lack Left Atrial Mechanical Contraction after Cryoablation

The customary recommendation is that oral anticoagulation be withdrawn a few months after cryoablation for atrial fibrillation, independently of left atrial mechanical contraction in patients in sinus rhythm. Recently, a 5-fold increase in stroke has been described in sinus-rhythm patients who lack atrial mechanical contraction. One aim of this study was to evaluate the efficacy of oral anticoagulation in preventing postoperative stroke in such patients. This prospective study divided 154 sinus-rhythm patients into 2 groups, depending on the presence (108 patients) or absence (46 patients) of left atrial mechanical contraction at 6 months after surgery, and monitored them annually for 5 years. Those without left atrial contraction were maintained on acenocumarol. The primary endpoint was the occurrence of ischemic stroke. The median follow-up period was 29 ± 16 months; 4 patients (2.5%), all belonging to the group with preserved atrial contraction, had ischemic stroke; the group of patients without left atrial contraction had no episodes of stroke during follow-up. Logistic binary regression analyses showed no evidence of factors independently predictive of stroke. Among anticoagulated patients in sinus rhythm without left atrial contraction, we found the incidence of stroke to be zero. In a small, nonrandomized group such as this, we cannot discount the element of chance, yet we suggest that maintaining anticoagulation might lower the incidence of stroke in this population.

Rationale and design of the Left Atrial Appendage Occlusion Study (LAAOS) III

BACKGROUND

Occlusion of the left atrial appendage (LAA) is a promising approach to stroke prevention in atrial fibrillation (AF). However, evidence of its efficacy and safety to date is lacking. We herein describe the rationale and design of a definitive LAA occlusion trial in cardiac surgical patients with AF.

METHODS

We plan to randomize 4,700 patients with AF in whom on-pump cardiac surgical procedure is planned to undergo LAA occlusion or no LAA occlusion. The primary outcome is the first occurrence of stroke or systemic arterial embolism over a mean follow-up of four years. Other outcomes include total mortality, operative safety outcomes (chest tube output in the first post-operative 24 hours, rate of post-operative re-exploration for bleeding in the first 48 hours post-surgery and 30-day mortality), re-hospitalization for heart failure, major bleed, and myocardial infarction.

RESULTS

Left Atrial Appendage Occlusion Study (LAAOS) III is funded in a vanguard phase by the Canadian Institutes for Health Research (CIHR), the Canadian Network and Centre for Trials Internationally, and the McMaster University Surgical Associates. As of September 9, 2013, 162 patients have been recruited into the study.

CONCLUSIONS

LAAOS III will be the largest trial to explore the efficacy of LAA occlusion for stroke prevention. Its results will lead to a better understanding of stroke in AF and the safety and efficacy of surgical LAA occlusion.

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.

Surgical strategies and devices for surgical exclusion of the left atrial appendage: a word of caution

In patients with chronic atrial fibrillation, 90% of clots are located in the left atrial appendage (LAA). Therefore, LAA exclusion is a means of preventing thrombus formation and subsequent thromboembolic events in these patients. The LAA can be excluded from the systemic circulation via surgical, percutaneous, or thoracoscopic approaches. The surgical aim is complete obliteration of the appendage without a significant increase in either postoperative complications (bleeding, arrhythmias) or recurrence. We discuss the current surgical techniques available for LAA obliteration and review their results.

Surgical Atrial Fibrillation Ablation: An Electrophysiologist's Perspective

The experience and insight obtained during surgical ablation of all types of arrhythmias was formative for electrophysiology and catheter ablation. The early surgical ablation experience provided proof of concept as well direct operative observation of anatomy and pathophysiologic mechanisms. For atrial fibrillation (AF), surgical ablation anticipated many of the problems that catheter ablation subsequently encountered, although these lessons were not promptly appreciated. Rather than competition, greater cooperation and communication between surgeons and electrophysiologists in the future would be more likely to enhance understanding of the underlying pathophysiology of AF.

Left atrial appendage occlusion by invagination and double suture technique

Left atrial appendage (LAA) plays a crucial role as a source of atrial thrombus in patients with atrial fibrillation (AF). Thus, the need to close LAA becomes evident in patients with AF who undergo concomitant mitral valve surgery. Unfortunately, it has been reported a high rate of unsuccessful LAA occlusion, regardless of the technique employed.We propose a safe and simple method for LAA occlusion consisting in invagination of the appendage into the left atrium, followed by two sutures (purse string suture around the base of the LAA and a reinforce running suture).

Catheter-based left atrial appendage occlusion procedure: role of echocardiography

Atrial fibrillation is a common, clinically significant arrhythmic disorder that results in increased risk of morbidity and mortality in affected patients. Atrial fibrillation is more prevalent among men compared with women and the risk for developing atrial fibrillation increases with advancing age. Ischaemic stroke is the most common clinical manifestation of embolic events from atrial fibrillation. While anticoagulation treatment is the preferred treatment, unfortunately, many patients have contraindications for anticoagulation treatment making this option unavailable to them. Previous data have shown that most thrombi that form in association with non-valvular atrial fibrillation occur in the left atrial appendage (LAA). It has been suggested that isolating the LAA from the body of the left atrium might reduce the risk of embolic events and that LAA obliteration may be a treatment option for patients with atrial fibrillation who are not candidates for anticoagulation treatment. Several procedures have been developed for isolation of the LAA, including surgical procedures as well as catheter-based ones. In this paper, we will review the currently available techniques, emphasizing the catheter-based ones. We will examine the increasing role of real-time three-dimensional transoesophageal echocardiography for appropriate screening and patient selection for these procedures, intra-procedural guidance, and follow-up care.

Non-pharmacologic management of atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice today. Contemporary medical treatment options include atrioventricular nodal blocking agents to control heart rates during AF, antiarrhythmic drugs aimed at maintaining normal sinus rhythm, and anticoagulation therapies to reduce stroke risk. Invasive treatment of AF has emerged because of the toxicities and lack of long-term efficacy of available antiarrhythmic medications along with the lack of improvement in symptoms for rate-controlled patients. The investigators review the evolution of the current catheter-delivered AF procedures, starting with surgical maze up to and including left atrial appendage occlusion devices. Individual catheter ablation targets, anatomic and electrophysiologic, are discussed, with a particular focus on the use of an incremental ablation target strategy dependent on the type of AF being treated. In conclusion, the history of invasive AF therapy provides a basic understanding of contemporary ablation strategies and a backdrop for the cutting-edge rhythm and stroke prevention therapies of today.

[Techniques for occlusion of the left atrial appendage: chances and risks]

Atrial fibrillation causes 15-20% of ischemic strokes and the overall risk of stroke in patients with non-valvular atrial fibrillation is about 5% per year globally. Warfarin has long been the cornerstone for decreasing risks of stroke in patients with atrial fibrillation and its efficacy has been well established. However, 14-44% of patients with atrial fibrillation who are at risk of stroke are ineligible for anticoagulation therapy, mostly owing to the risks of major bleeding and falls. Occlusion of the left atrial appendage (LAA) appears to be an interesting new tool to prevent thromboembolic events in selected cases. In addition to surgical techniques, percutaneous transcatheter approaches have been introduced to occlude the LAA. Recent results indicate non-inferiority of mechanical occlusion of the LAA in comparison to warfarin therapy.

Histologic evaluation of stapled right atrial appendages with fabric buttressing

OBJECTIVE

The aim of this study was to histologically evaluate the importance of using buttressing materials in stapling the atrial appendages.

METHODS

We stapled the right atrial appendage with a commercial apparatus in 11 mongrel dogs. To evaluate the efficiency of using a buttressing material as an adjunct to stapling, we conducted 30-day studies without (group A: n = 2) or with buttressing material (group B: n = 3) and 90-day studies without (group C: n = 3) or with buttressing material (group D: n = 3) and thereafter made assessments using Doppler echocardiography and performed histologic analyses on all stapled appendages.

RESULTS

During surgery, blood oozing from the stapling sites was observed in four of five cases of groups A and C; with buttressing, there was no oozing in groups B and D. In groups A and B, we observed the myocardium of the appendage being focally replaced with fibrous tissue. Myocardium in group C was infiltrated diffusely with loose fibrous tissue and in group D had been almost completely replaced with fibrous tissue.

CONCLUSIONS

The buttressing material was useful not only in preventing oozing but also likely promoting the growth of fibrous tissue in the right atrial appendage.

Percutaneous closure of left atrial appendage to prevent embolic events in high-risk patients with chronic atrial fibrillation

BACKGROUND

Percutaneous closure of the left atrial appendage (LAA) is a novel alternative for the treatment of patients with atrial fibrillation (AF) and with a high risk of stroke who are not eligible for long-term anticoagulation therapy. The aim of this study was to asses the safety, feasibility, and long-term efficacy of this procedure.

METHODS

From July 2004 to June 2007, 20 patients (13 male, mean age 69 +/- 8 years) with non-valvular AF (NV-AF) underwent LAA percutaneous closure using the PLAATO system, implanted through a transeptal access. All patients had contraindications to anticoagulant therapy and were at high risk for cardioembolic stroke (mean CHADS(2) score 3 +/- 1.2). A trans-thoracic echocardiogram was performed at 1, 3, and every 6 months after the procedure, whereas a trans-oesophageal echocardiogram (TOE) was scheduled at 6 months. After 24 months, a phone interview was obtained.

RESULTS

All procedures were successfully performed in 18 patients. In two patients, LAA closure was not feasible for the presence of a multilobed LAA. Two patients underwent percutaneous closure of patent foramen ovale in the same session. In one patient, the procedure was complicated by cardiac perforation with pericardial effusion, treated with pericardiocentesis. At a mean follow up of 40 +/- 10 months, no embolic events occurred. One patient died, after 36 months, for gastric cancer. TOE examination showed the complete exclusion of the LAA in all patients.

CONCLUSIONS

Percutaneous closure of LAA is safe and efficacious to prevent stroke in patients with NV-AF at high risk for cardioembolic events, with contraindications to anticoagulant therapy.

Left atrial appendage can still cause clinical events after ligation

We present a 71-year-old female patient with transient ischaemic attack. A thrombus located at the stump of previously ligated left atrial appendage was suspected as the cause of event.