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

Risk factors, clinical implications, and management of peridevice leak following left atrial appendage closure: A systematic review

BACKGROUND

Left atrial appendage closure (LAAC) is a treatment modality for stroke prevention in patients with atrial fibrillation (AF). One of the potential complications of LAAC is a peri-device leak (PDL), which could potentially increase the risk of thromboembolism formation.

METHODS

This systematic review was done according to PRISMA guidelines. Using four databases, all primary studies through April 2022 that met selection criteria were included. Outcomes of interest were studies reporting on PDL characteristics, risk factors and management.

RESULTS

A total of 116 studies met selection criteria (97 original studies and 19 case reports/series). In the original studies (n = 30,133 patients), the weighted mean age was 72.0 ± 7.4 years (57% females) with a HAS-BLED and CHA2DS2-VASc weighted means of 2.8 ± 1.1 and 3.8 ± 1.3, respectively. The most common definition of PDL was based on size; 5 mm: major, 3-5 mm: moderate, < 1 mm minor, or trivial. Follow up time for PDL detection was 7.15 ± 9.0 months. 33% had PDL, irrespective of PDL severity/size, and only 0.9% had PDL of greater than 5 mm. The main risk factors for PDL development included lower degree of over-sizing, lower left ventricular ejection fraction, device/LAA shape mismatch, previous radiofrequency ablation, and male sex. The most common methods to screen for PDL included transesophageal echocardiogram and cardiac CT. PDL Management approaches include Amplatzer Patent Foramen Ovale occluder, Hookless ACP, Amplatzer vascular plug II, embolic coils, and detachable vascular coils; removal or replacement of the device; and left atriotomy.

CONCLUSION

Following LAAC, the emergence of a PDL is a significant complication to be aware of. Current evidence suggests possible risk factors that are worth assessing in-depth. Additional research is required to assess suitable candidates, timing, and strategies to managing patients with PDL.

Is It Safe to Preserve Left Atrial Appendage During Maze Procedure?

BACKGROUND AND OBJECTIVES

The left atrial appendage (LAA) can contribute significantly to LA mechanical contraction. Nevertheless, the preventive effect of LAA occlusion during the maze procedure against cerebral infarction remains controversial. In this study, we compared the surgical, cardiac hemodynamic, and neurologic outcomes between LAA preservation and occlusion performed during the maze procedure.

METHODS

Between January 2015 and August 2021, 252 patients underwent the maze procedure using cryoablation at our medical center. After excluding patients according to our exclusion criteria (i.e., mechanical prosthesis implantation, preexisting LAA thrombus), LAA was preserved in 113 patients (non-occlusion group) and occluded in 75 patients (occlusion group). Outcomes were compared using propensity score matching (PSM).

RESULTS

PSM did not reveal significant intergroup differences in baseline characteristics between the non-occlusion (n=53) and occlusion (n=53) groups. During a median follow-up of 44 months, 2 patients in the non-occlusion group (3.8%) experienced ischemic strokes. There was no significant difference in the rate of freedom from stroke (p=0.19) and major adverse cardiac events (p=0.43) between the 2 groups. Through echocardiography at 1-year follow-up, a statistically significant difference in LA mechanical contraction was observed between the non-occlusion group and occlusion group (24 of 33 [72.7%] vs. 18 of 37 [48.6%], respectively; p=0.04).

CONCLUSIONS

In this study, preservation of the LAA during the maze procedure resulted in better LA function than LAA occlusion, with similar rates of stroke.

Left Atrial Appendage Occlusion for Stroke Prevention in Nonvalvular Atrial Fibrillation

The majority of embolic strokes in patients with nonvalvular atrial fibrillation are caused by thrombi in the left atrial appendage. It is projected that strokes related to atrial fibrillation will markedly increase in the future unless effective mitigation strategies are implemented. Systemic anticoagulation has been known to be highly effective in reducing stroke risk in patients with atrial fibrillation. However, bleeding complications and nonadherence are barriers to effective anticoagulation therapy. Surgical and percutaneous left atrial appendage occlusion devices are nonpharmacologic strategies to mitigate the challenges of drug therapy. We present a contemporary review of left atrial appendage occlusion for stroke prevention in nonvalvular atrial fibrillation. A thorough review of the history of surgical and percutaneous left atrial appendage occlusion devices, recent trials, and US Food and Drug Administration milestones of current left atrial appendage occlusion devices are discussed.

Impact of Left Atrial Appendage Exclusion on Short-Term Outcomes in Isolated Coronary Artery Bypass Graft Surgery

BACKGROUND

The objective of this study was to evaluate the impact of left atrial appendage (LAA) exclusion on short-term outcomes in patients with atrial fibrillation undergoing isolated coronary artery bypass graft surgery.

METHODS

We queried the 2010 to 2014 National Readmissions Database for patients who underwent coronary artery bypass graft repair with and without LAA ligation by using International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes (International Classification of Diseases, Ninth Revision, Clinical Modification: 36.1xx). Only patients with a history of atrial fibrillation were included in our analysis. The primary outcome of our study was 30-day readmissions following discharge. Secondary outcomes were in-hospital mortality and stroke. To assess the postoperative outcomes, we used multivariate logistic regression models to adjust for clinical and demographic covariates.

RESULTS

In total, we analyzed 253 287 patients undergoing coronary artery bypass graft surgery, 7.0% of whom received LAA closure. LAA exclusion was associated with a greater risk of postoperative respiratory failure (8.2% versus 6.2%, P<0.0001) and acute kidney injury (21.8% versus 18.5%, P<0.0001), but it did not significantly change the rate of blood transfusions or occurrence of cardiac tamponade. LAA exclusion was associated with a nonsignificant reduction in stroke (7.9% versus 8.6%, P=0.12), no difference in in-hospital mortality (2.2% versus 2.2% P=0.99), and a greater risk of 30-day readmission (16.0% versus 9.6%, P<0.0001). After covariate adjustment, LAA ligation remained a significant predictor of 30-day readmission (odds ratio, 1.640 [95% CI, 1.603-1.677], P<0.0001).

CONCLUSIONS

LAA exclusion during isolated coronary artery bypass graft surgery in patients with atrial fibrillation is associated with a higher rate of 30-day readmission. Postoperative measures to mitigate the loss of the hormonal and hemodynamic effects of the LAA may increase the therapeutic benefit of this procedure.

Exclusion versus preservation of the left atrial appendage in rheumatic mitral valve surgery

OBJECTIVES

This study aimed to evaluate the impact of left atrial appendage exclusion on clinical outcomes in patients with atrial fibrillation (AF) undergoing rheumatic mitral surgery.

METHODS

We retrospectively reviewed 1226 consecutive patients with AF (54.5±11.6 years; 68.2% females) who underwent rheumatic mitral valve (MV) surgery from 1997 to 2016. The left atrial appendage was preserved in 836 (68.2%) and excluded in 390 (31.8%) patients. Surgical AF ablation was performed in 506 (60.5%) and 304 (77.9%) patients with preserved and excluded left atrial appendage, respectively. For baseline adjustment, propensity matching was used.

RESULTS

During a median follow-up of 63.4 months (IQRs, 20-111 months), there were no significant intergroup differences in the risks of mortality (2.77% vs 3.03%/patient-years) and thromboembolic events (0.91% vs 1.02%/patient-years). In the 258 pairs of propensity-score matched patients, death (2.77% vs 3.03%/patient-years) and thromboembolism (1.36% vs 0.82%/patient-years) outcomes were comparable for both groups. In a subgroup undergoing ablation (n=810), there were no significant differences in the adjusted risks of death (HR, 0.67; 95% CI, 0.34 to 1.32) and thromboembolism (HR, 0.47; 95% CI, 0.18 to 1.26). In a subgroup not undergoing ablation (n=416), however, left atrial appendage preservation tended to have higher adjusted risks for death (HR, 2.24; 95% CI, 0.98 to 5.13) and thromboembolism (HR, 4.41; 95% CI, 0.97 to 20.1).

CONCLUSIONS

Left atrial appendage preservation did not seem to have greater risks of adverse clinical events in patients with AF undergoing rheumatic MV surgery particularly when ablation procedure is combined.

Pericardial patch closure of left atrial appendage orifice

Seven patients underwent pericardial patch closure of the left atrial appendage orifice in our clinic. Usually 5-to-7 U-sutures with 4-0 prolene were placed to the left atrial appendage orifice. These sutures were stretched out to measure exact sizes of the left atrial appendage orifice. Then, U-sutures were passed through the pericardial patch which was treated with glutaraldehyde. Pericardium was placed over the left atrial appendage orifice through the left atrium and stay sutures were tied. The upper suture was continuously sutured along the border of the orifice clockwise and tied to the lower suture. The lower suture was continuously sutured in a counter-clockwise direction and tied to the upper suture. Then, mitral valve surgery (repair or replacement) was performed.

Current State of Surgical Left Atrial Appendage Exclusion: How and When

Left atrial appendage exclusion is efficacious for stroke prophylaxis in patients with atrial fibrillation. Surgical excision provides reliable left atrial appendage exclusion, whereas surgical occlusion does not. Specifically, 2-layer internal suture ligation has a high failure rate. Left atrial appendage exclusion concomitant to another cardiac surgical procedure is indicated in patients with atrial fibrillation but not in patients without baseline atrial fibrillation. Studies currently underway will further define the role of concomitant surgical left atrial appendage exclusion, especially for the population without baseline atrial fibrillation but at high risk of developing postoperative atrial fibrillation.

Cardiovascular Therapies Targeting Left Atrial Appendage

Left atrial appendage (LAA) closure has evolved as an effective strategy for stroke prevention in patients with atrial fibrillation who are considered suitable for oral anticoagulation. There is strong evidence based on randomized clinical trials with 1 percutaneous device, as well as a large registry experience with several devices, regarding the safety and efficacy of this strategy. In addition, there is encouraging data regarding the effect of epicardial LAA closure on decreasing arrhythmia burden and improvements in systemic homeostasis by neurohormonal modulation. However, there are several unresolved issues regarding optimal patient selection, device selection, management of periprocedural complications including device-related thrombus, residual leaks, and pericarditis. In this review, we summarize the rationale, evidence, optimal patient selection, and common challenges encountered with mechanical LAA exclusion.

The Treatment of Left Atrial Appendage Aneurysm by a Minimally Invasive Approach

Left atrial appendage (LAA) aneurysm is a rare, pathologic condition that may lead to atrial tachyarrhythmia or thromboembolic events. A 49-year-old man presented with aggravated palpitation and dizziness. He suffered from refractory atrial fibrillation despite a previous history of radiofrequency catheter ablation. Echocardiography revealed a 57-mm LAA aneurysm. Surgical ablation was performed through a right mini-thoracotomy, and the LAA aneurysm was obliterated with a 50-mm AtriClip (Atricure Inc., Westchester, OH, USA). However, follow-up computed tomography showed residual communication, so the patient is still taking warfarin. We report that a minimally invasive strategy for treating LAA aneurysm can be considered, but incomplete closure may occur; thus, caution is needed.

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.

Incomplete Closure of the Left Atrial Appendage: Implication and Management

Incomplete left atrial appendage closure (LAAC) occurs in ∼30-40 % of cases following both surgical and percutaneous closure methods. Incomplete surgical LAAC may further be classified as incompletely surgically ligated LAA (ISLL) or LAA stump. ISLL is associated with a significantly increased risk of thrombus formation/thromboembolism. Moreover, this risk is highest in the absence of oral anticoagulation (OAC) and inversely correlates with the size of the ISLL neck. Not only routine screening for ISLL seems critical, but also long-term OAC should strongly be considered in this high-risk cohort. Alternatively, complete endocardial occlusion using a surrogate method may represent a reasonable option, particularly in those intolerant to long-term OAC therapy. Although thrombus formation/thromboembolic events have also been described in patients with incomplete LAAC following percutaneous occlusion, an association between the two remains less clear. However, given the rise and growing interest in percutaneous LAAC methods, additional research in this area is clearly warranted.

Predictors of thrombus formation after percutaneous left atrial appendage closure using the WATCHMAN device

Percutaneous left atrial appendage (LAA) closure using the WATCHMAN device is a novel option for prevention of stroke associated with atrial fibrillation. However, device-related thrombus (DRT) formation is a concern after WATCHMAN implantation and the predictors of DRT still remain unclear. We aimed to clarify the predictors of DRT after WATCHMAN implantation by analyzing 78 patients (50 males, 72 ± 8 years, average CHA2DS2-VASc score of 4.3 + 1.8) who had undergone WATCHMAN implantation. WATCHMAN was successfully implanted in all patients and four (5%) developed DRT. Patients with DRT were more often female (75 vs. 34%, p = 0.094). CHA2DS2-VASc score was higher for patients with DRT (6.3 ± 2.5 vs. 4.2 ± 1.7, p = 0.022). Chronic kidney disease (100% vs. 43%, p = 0.024) and deep implantation of the device, which was defined as implant position below the LAA ostial plane (75 vs. 24%, p = 0.026), were more common in patients with DRT. HAS-BLED score (4.5 ± 1.0 vs. 3.5 ± 1.1, p = 0.074) was higher and oral anticoagulants (50 vs. 84%, p = 0.086) were less commonly prescribed for patients with DRT. Multivariable logistic regression analysis showed that higher CHA2DS2-VASc score (p = 0.022, OR 2.8) and deep implantation (p = 0.032, OR 24.7) were associated with DRT. These results suggest the possible role of CHA2S2-VASc scores and implantation depth in the development of DRT after percutaneous LAA closure using the WATCHMAN device.

Epicardial left atrial appendage closure-comparison of surgical techniques in an ex vivo model

BACKGROUND

Formation of clots in the left atrial appendage (LAA) may lead to embolism and consecutive cerebral stroke. This risk is reduced by closure and resection. To address the efficacy of surgical LAA closure, resilience to pneumatic pressure was studied. Different surgical techniques were compared in an experimental model.

METHODS

From freshly slaughtered pigs cardiopulmonary preparations were taken. The left atrium was clamped airtight and the LAA was cannulated. Via a manually operated pump pressure was applied and a digital pressure gauge was connected. Four groups (each n=12) with different epicardial closures were studied: (I) purse string; (II) single layered continuous suture; (III) double layered suture; (IV) surgical stapler. A nonparametric test was used for group comparisons of mean burst pressures (mmHg). Statistical significance was defined at P<0.05.

RESULTS

Mean burst pressures in group 1 amounted to 97.1±13.0 mmHg, in group 2 to 105.5±13.3 mmHg, in group 3 to 124.6±14.2 mmHg and in group 4 to 136.6±12.5 mmHg. Excepting differences between groups 1 and 2 comparisons between groups were significantly different.

CONCLUSIONS

In an ex vivo model surgical staplers and double layered hand crafted sutures proved well suitable for closure of the LAA. They were significantly superior to single layered sutures in terms of resilience to pneumatic pressure. This may be relevant to durability and should be discussed with regard to clinical choice.

Pneumatic Burst Pressures After Inverted Closure of the Left Atrial Appendage: An Ex Vivo Model

BACKGROUND

The left atrial (LA) appendage (LAA) is the main source of thromboembolism in atrial fibrillation. This study addressed initial pressure resistance of surgical LAA closures.

METHODS

In an experimental model, pneumatic pressure resistances of different surgical closure techniques were examined, and variations in technique and access were studied. In preparations of the LA from freshly slaughtered pigs, pneumatic pressure was applied to the LAA. Burst pressures (mbar) of various closure techniques (n = 12 specimens per group) were measured: (1) epicardial double-layer suture, (2) epicardial stapler closure (staple height 2 mm), (3) epicardial stapler closure (staple height 4, 4.5, and 5 mm), (4) endocardial inverse double-layer suture, (5) endocardial inverse stapler seam (staple height 2 mm), and (6) endocardial inverse stapler seam (staple height 4, 4.5, and 5 mm).

RESULTS

The mean burst pressure in group 1 was 175.5 ± 19.35 mbar. There was no significant difference compared with group 2 (174.5 ± 28.45 mbar) or group 3 (176 ± 27.69 mbar). Group 4 scored significantly higher than all other groups (198.9 ± 18.35 mbar). Burst pressures in group 5 (136.2 ± 16.68 mbar) were significantly lower than in group 4 and in group 6 (165.1 ± 21.94 mbar), but the differences between groups 5 and 6 were also significant.

CONCLUSIONS

In an ex vivo model, double-layer suturing of the inverted LAA from an internal LA access led to higher burst pressures compared with epicardial suturing and with both endocardial and epicardial stapled closures.

Device-associated thrombus formation after left atrial appendage occlusion: A systematic review of events reported with the Watchman, the Amplatzer Cardiac Plug and the Amulet

OBJECTIVES

This study aimed to provide a systematic review of device-associated thrombosis (DAT) after left atrial appendage occlusion (LAAO) with the Watchman, Amplatzer Cardiac Plug, and Amulet devices.

BACKGROUND

DAT is known as a complication of LAAO but data about its clinical impact is scarce.

METHODS

A systematic review of studies evaluating the incidence, treatment and clinical implications of DAT from January 2008 to September 2015 was conducted.

RESULTS

A total of 30 studies describing DAT events were included in the analysis. The overall incidence of DAT was 3.9% (82 DAT for 2118 implanted devices). The median time from procedure to diagnosis of DAT was 1.5 months (IQR: 0-2.9). Most cases were diagnosed with transesophageal echocardiogram (TEE). The treatment consisted of low molecular weight heparin (LMWH) in 45.5% of cases, and oral anticoagulation (OAC) or other treatment modalities in 54.5%. Complete thrombus resolution was achieved in 95.0% of cases (100% with LMWH and 89.5% with OAC). Treatment duration varied greatly with a median treatment duration of 45 days (IQR: 14-135). Clinical events related to DAT consisted of neurologic events namely two transient ischemic attacks (2.4%) and four ischemic strokes (4.9%).

CONCLUSIONS

DAT is an infrequent complication of percutaneous LAAO. It occurs mainly early after the procedure and is associated with a low rate of neurological complications. In the majority of cases, diagnosis is made during follow-up imaging with TEE. Anticoagulation treatment seems to be safe and highly effective. Further studies are needed to evaluate the optimal management of DAT. © 2017 Wiley Periodicals, Inc.

Left atrial appendage occlusion in atrial fibrillation for stroke prevention: A systemic review

BACKGROUND

Atrial fibrillation (AF) is an arrthymia characterized by increased risk of ventricle arrthymias and thromboembolism especially ischemic stroke. Most thrombus originated in the left atrial appendage, thus left atrial occlusion (LAAO) may be an effective alternative for stroke prevention in atrial fibrillation.

OBJECTIVE

To assess the effect and safety of left atrial occlusion for stroke prevention in atrial fibrillation.

METHODS AND RESULTS

We searched Pub Med, CENTRAL in The Cochrane Library, Embase, CBM-Disk, CNKI for published trials, ClinicalTrials.gov, ISI Proceedings for conference abstracts, and WHO International Clinical Trial registration Platform for ongoing studies. The search results were extracted, and then the quality of included studies was assessed. By RevMan 5.3, meta analysis was used if there was low heterogeneity. Three randomized controlled clinical trials involving 1165 participants were included (percutaneous 1114 in 2 trials, surgical 51 in 1 trial). The current data suggest that left atrial occlusion may be as efficacious as warfarin in stroke prevention (RR 0.78 [0.33, 1.84]) and mortality reduction (RR 0.68 [0.40, 1.16]) for AF.

CONCLUSION

In contrast to warfarin left atrial occlusion with Watchman device may have the same effectivity in stroke reduction. Surgical LAAO may also get positive outcomes compared with warfarin, but owing to the small sample size the evidence is less powerful. Total outcomes of percutaneous and surgical LAAO support this approach.

Early results with the LARIAT device for left atrial appendage exclusion in patients with atrial fibrillation at high risk for stroke and anticoagulation

OBJECTIVES

To evaluate early outcomes of left atrial appendage (LAA) closure via a percutaneous LAA ligation approach with the SentreHeart LARIAT(™) snare device.

BACKGROUND

Atrial fibrillation increases the risk of stroke 4-5 fold, which can have devastating outcomes. Exclusion of the LAA is believed to decrease the risk of embolic stroke.

METHODS

Twenty-seven patients with atrial fibrillation, a high risk of stroke, and contraindication or intolerance for anticoagulation therapy underwent percutaneous ligation of the LAA with the LARIAT device. Initial LAA closure was confirmed with TEE and contrast fluoroscopy.

RESULTS

The acute procedural success was 92.6%. One patient sustained a perforation of the LAA and was treated conservatively. The patient underwent LAA closure surgically the next day. In one patient the attempt to advance the LARIAT over the LAA was unsuccessful. Patients were followed for a mean of 4 months. Preserved LAA closure was confirmed with a 45 day follow-up TEE in 22 of 25 patients completing the procedure. Peri-operative complications included three cases of pericarditis and one case of a periprocedural CVA due to thrombus formation on the transseptal sheath. During follow-up, there was one stroke thought to be noncardioembolic and one pleural effusion. There were no deaths.

CONCLUSIONS

These results show that percutaneous LAA exclusion can be achieved successfully with an acceptable rate of periprocedural and short-term complications. Further studies and longer follow-up are needed to determine whether LAA exclusion lowers the long-term risk of thromboembolic events in patients with AF and contraindications to anticoagulation.

Left atrial appendage exclusion for prevention of stroke in atrial fibrillation: review of minimally invasive approaches

Stroke prevention is of vital importance in the management of atrial fibrillation (AF), though the proven strategy of systemic anticoagulation for thromboembolic prophylaxis is underutilized for a variety of reasons. The left atrial appendage (LAA) has long been suspected as the principal source of arterial emboli, particularly in nonvalvular AF, and a variety of techniques for its exclusion from the circulation have been developed. This review highlights the history of the LAA as a target of intervention, and the parallel advances in three minimally invasive strategies for its exclusion: percutaneous occlusion of the LAA orifice from within the left atrium, closed-chest ligation via a percutaneous pericardial approach, and minimally invasive thoracoscopic surgery. While further study is necessary, available evidence suggests that effective LAA exclusion is becoming a viable alternative to anticoagulation for stroke prevention in nonvalvular AF.

Incomplete left atrial appendage occlusion and thrombus formation after Watchman implantation treated with anticoagulation followed by further transcatheter closure with a second-generation Amplatzer Cardiac Plug (Amulet device)

We report a case of incomplete left atrial appendage (LAA) closure after Watchman device (Atritech, Boston Scientific, Natrick, MA) implantation which subsequently developed a thrombus 3 years after the initial procedure. The thrombus resolved after a short period of anticoagulation with warfarin, and the LAA was successfully occluded with a second-generation Amplatzer Cardiac Plug (Amulet device, AGA, St Jude Medical, Minneapolis, MN). Incomplete LAA closure may be associated with increased risk of thrombus formation and further closure with a second device after a course of anticoagulation may be a reasonable and feasible strategy. © 2014 Wiley Periodicals, Inc.

Left atrial appendage resection versus preservation during the surgical ablation of atrial fibrillation

BACKGROUND

Left atrial appendage (LAA) resection during the Maze procedure may decrease thromboembolic risks, but its preservation may improve left atrial contractile function. This study compared the clinical effects of LAA resection and preservation after the Maze procedure.

METHODS

A retrospective review was made of 379 patients (mean age 53.3 ± 12.6 years, 244 females) who underwent the cryo-Maze procedure in conjunction with mitral surgery from 1999 to 2011. The LAA was resected in 187 patients (resection group) but preserved in 192 patients (preservation group). Outcomes were compared using a propensity score study design based on 20 baseline characteristics to obtain well-matched patient pairs.

RESULTS

Propensity score matching yielded 119 pairs of patients in whom there were no significant differences in baseline profiles between the two groups. During a mean follow-up of 3.1 ± 2.8 years, there were 16 deaths, 6 cases of stroke, and 39 cases of atrial fibrillation recurrence. There were no significant differences in stroke-free survival (p = 0.88) and freedom from AF while off antiarrhythmic drugs (p = 0.46) between the two groups. On serial echocardiographic assessments, patients in the preservation group showed a higher transmitral A-wave velocity (peak atrial contraction wave velocity; p = 0.47, 0.020, and 0.001 at 3, 6, and 12 months, respectively) and lower E/A ratio (peak early filling wave [E-wave] velocity / A-wave velocity; p = 0.34, 0.065, and 0.001 at 3, 6, and 12 months, respectively) at each timepoint compared with the resection group.

CONCLUSIONS

Preservation of the LAA during the Maze procedure resulted in similar clinical and rhythm outcomes, but LA contractile function superior to that of LAA resection.

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.

Transcatheter left atrial appendage occlusion

Occlusion of the left atrial appendage (LAA) may reduce the risk of stroke in patients with atrial fibrillation (AF). Trials comparing LAA occlusion to warfarin anticoagulation in patients with nonvalvular AF showed a reduction in hemorrhagic stroke, although an increase in safety events due to procedural complications. Long-term follow-up suggests possible superiority of LAA occlusion due to fewer strokes and bleeding events. The superior dosing and safety profiles of the novel oral anticoagulants raise the accepted threshold for safety and efficacy of LAA occlusion procedures, and underscore the need for randomized studies comparing LAA occlusion with these newer anticoagulants.

[Surgical closure of the left atrial appendage in patients with atrial fibrillation. Indications, techniques and results]

Cardiac embolisation in patients with atrial fibrillation accounts for the most serious complication of cerebral infarction. The left atrial appendage resembles the origin of these cardiac emboli in the majority of cases, although other anatomical areas of the left atrium might also be prerequisites for thrombus formation. Surgical closure of the left atrial appendage during an ablation therapy incorporates the theoretical possibility of reducing the rate of cardiac cerebral infarction. In order to achieve closure, different surgical strategies exist: either exclusion by over-sewing or snaring or excision by using scissors or a stapling device. All therapies incorporate pros and cons. One of the major complications and most feared side-effect is the recanalisation of a formerly closed left atrial appendage, especially in a thrombus filled left atrial appendage cavity. But also reopening of the formerly closed orificium and still existing remnants with communication to the left atrium might stand for an increased risk. Due to the good results of left atrial appendage excision, this surgical therapy at the moment presents the surgical gold standard, as this therapy is recommended in the updated ESC guidelines for the management of atrial fibrillation. If excision of the left atrial appendage will reduce the risk of cardiac embolisation needs to be examined in large prospective-randomized trials with a controlled systemic follow-up. So far, excision of the left atrial appendage as an alternative to oral anticoagulation, especially in patients with atrial fibrillation, is not recommended.

Stroke prevention in atrial fibrillation: atrial appendage closure

The left atrial appendage (LAA) is the primary nonvalvular cause of cardioembolic stroke in patients with atrial fibrillation (AF). Warfarin and direct thrombin inhibitors such as dabigatran are presumed to prevent formation of LAA thrombus, and are first-line treatments to prevent ischemic stroke in AF. However, these medications carry many contraindications such as hemorrhage, and can interact with many drugs and supplements. Epicardial and endovascular techniques for occlusion of LAA are being explored, whether to mitigate the need for anticoagulation in patients at risk of bleeding or as a first-line therapy to reduce the risk of thromboembolic stroke. The purposes of this article are to 1) review the LAA structure and its potential contribution to ischemic stroke; 2) discuss the results of surgical and endovascular trials of LAA occlusion on risk of stroke and adverse events in AF patients; and 3) present early data on devices in development.

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.

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.

Serious Complications from Dislocation of a Watchman Left Atrial Appendage Occluder

Left atrial appendage (LAA) elimination is regarded to protect patients with atrial fibrillation (AF) from stroke or embolism. The Watchman occluder is a device for percutaneous LAA occlusion and is at present investigated in the PROTECT AF trial. In a 78-year-old man, embolization of the Watchman device occurred 10 minutes after implantation. At emergency cardiac surgery, the device was removed from the aortic valve and an aortic bioprosthesis and a pacemaker had to be implanted. One year postoperatively, he still suffers from heart failure. This case shows that percutaneous LAA occlusion may result in serious complications.