Medical Policy

Policy Num:       07.001.168
Policy Name:     Surgical Left Atrial Appendage Occlusion Devices for Stroke Prevention in Atrial Fibrillation
Policy ID:          [07.001.168][Ac / B / M / P ][7.01.172]

Last Review:       September 7, 2022
Next Review:      September 7, 2023
Issue:                   9:2022

Related Policies:
2.002.034 - Percutaneous Left Atrial Appendage Closure Devices for Stroke Prevention in Atrial Fibrillation

Surgical Left Atrial Appendage Occlusion Devices for Stroke Prevention in Atrial Fibrillation

Summary

Description

Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. Stroke associated with AF is primarily embolic, tends to be more severe than the typical ischemic stroke, and causes higher rates of mortality and disability. As a result, stroke prevention is one of the main goals of AF treatment. Treatment with anticoagulant medications is a first-line approach to stroke prevention in individuals with AF, although occlusion of the left atrial appendage (LAA) may offer a non-pharmacological alternative to anticoagulant medications for those with a contraindication or intolerance to long-term anticoagulant use or with poor anticoagulant adherence. Multiple surgical techniques may be used to excise or occlude the LAA. One device, the AtriClip Left Atrial Appendage Exclusion System, has approval from the U.S. Food and Drug Administration for surgical LAA occlusion for stroke prevention in patients with AF.

Summary of Evidence

For individuals with AF at increased risk for embolic stroke undergoing LAA occlusion with an AtriClip device concomitant with open or thoracoscopic cardiac surgical procedures, the evidence includes a randomized controlled trial (RCT), a controlled observational study, and case series. Relevant outcomes are ischemic stroke, cardiac events, and mortality. Although evidence from several systematic reviews and a large (N>10,000) observational study found surgical LAA occlusion associated with a reduction in the risk of stroke without an increase in the risk of adverse events, direct evidence specifically comparing the AtriClip Left Atrial Appendage Exclusion System with anticoagulation, another surgical occlusion method, or no occlusion is limited. LAA occlusion was associated with a reduced risk of stroke versus no occlusion in the Left Atrial Appendage Occlusion Study (LAAOS) III trial, but the trial was not designed to specifically assess the net health benefit of LAA occlusion with an AtriClip device. A retrospective database study that compared the AtriClip device with no occlusion found that AtriClip placement was associated with a lower risk of ischemic stroke, which was not statistically significant, and a reduced risk of thromboembolism that was of marginal statistical significance. Large (N>100) case series of AtriClip device use with 2- to 3- years follow-up reported stroke rates ≤1% in the postoperative period and ≤2% in the long-term follow-up. Well-designed RCTs with follow-up of 1 year or more comparing the AtriClip device with anticoagulation, other surgical occlusion methods, and/or no occlusion are needed to provide adequate evidence for assessment of net health benefit. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

For individuals with AF at increased risk for embolic stroke undergoing LAA occlusion with an AtriClip device as a stand-alone procedure, the evidence includes a controlled observational study and case series. Relevant outcomes are ischemic stroke, cardiac events, and mortality. One small (N=40) industry sponsored retrospective observational study reported that use of the AtriClip device as a stand-alone procedure resulted in similar outcomes compared to percutaneous LAA occlusion. This evidence is too limited to draw definitive conclusions. Well-designed RCTs with follow-up of 1 year or more comparing stand-alone AtriClip device placement with percutaneous LAA occlusion are needed to provide adequate evidence for assessment of net health benefit. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

Additional Information

Not applicable.

Objective

The objective of this evidence review is to evaluate whether surgical occlusion of the left atrial appendage with an AtriClip device improves the net health outcome in individuals with atrial fibrillation at increased risk for embolic stroke.

Policy Statements

The use of surgical left atrial appendage occlusion devices, including the AtriClip device, for stroke prevention in individuals with atrial fibrillation undergoing open or thoracoscopic cardiac procedures is considered investigational.

The use of surgical left atrial appendage occlusion devices, including the AtriClip device, for stroke prevention as a stand-alone procedure for stroke prevention in individuals with atrial fibrillation is considered investigational.

Policy Guidelines

Coding

See the Codes table for details.

Benefit Application

BlueCard/National Account Issues

State or federal mandates (eg, Federal Employee Program) may dictate that certain U.S. Food and Drug Administration‒approved devices, drugs, or biologics may not be considered investigational, and thus these devices may be assessed only by their medical necessity.

Background

Atrial Fibrillation

Nonvalvular atrial fibrillation (AF) is the most common type of cardiac arrhythmia, affecting at least 2.7 million people in the United States. The risk of AF has been found to be lower in Black, Hispanic, and Asian patients relative to White patients, following adjustment for demographic and AF risk factors.[Dewland TA, Olgin JE, Vittinghoff E, et al. Incide.... 128(23): 2470-7. PMID 24103419][Mou L, Norby FL, Chen LY, et al. Lifetime Risk of.... 11(7): e006350. PMID 30002066] AF is typically described according to frequency and duration and includes paroxysmal (duration up to 1 week), persistent (>1 week), long-term persistent (>1 year), or permanent (normal sinus rhythm cannot be restored despite treatment).[Nesheiwat Z, Goyal A, Jagtap M. Atrial Fibrillatio.... Publishing; November 28, 2021.] Stroke is the most serious complication of AF. The estimated incidence of stroke in non-treated patients with AF is 5% per year. Despite a lower risk of AF, Black and Hispanic patients have an increased risk of stroke compared with White patients.[Gardener H, Sacco RL, Rundek T, et al. Race and Et.... 1(4): 1064-1069. PMID 32078475][Guo J, Gabriel N, Magnani JW, et al. Racial and Ur.... 2021; 9: 780185. PMID 34805085] Although this paradox may be partially attributable to clinical factors (e.g., congestive heart failure, hypertension, type 2 diabetes), Black and Hispanic patients with AF are less likely than White patients to receive stroke prevention therapy.[Tamirisa KP, Al-Khatib SM, Mohanty S, et al. Racia.... ppl): S137-S148. PMID 34993443] Stroke associated with AF is primarily thromboembolic, tends to be more severe than the typical ischemic stroke, and causes higher rates of mortality and disability. As a result, stroke prevention is one of the main goals of AF treatment.

Stroke Prevention

The risk for stroke among patients with AF is evaluated using several factors. Two commonly used scores, the CHADS₂ score and the CHA₂DS₂-VASc score are described in Table 1:

Table 1. CHADS₂ and CHA₂DS₂-VASc Scores to Predict Ischemic Stroke Risk in Patients With Atrial Fibrillation

Adapted from Lip et al (2018)[Lip GYH, Banerjee A, Boriani G, et al. Antithrombo.... 4(5): 1121-1201. PMID 30144419] and January et al (2014)[January CT, Wann LS, Alpert JS, et al. 2014 AHA/AC.... ; 64(21): e1-76. PMID 24685669]

Stroke in AF occurs primarily as a result of thromboemboli from the left atrium. The erratic atrial contractions in AF lead to blood stasis in the left atrium, and this low flow state increases the risk for thrombosis. The first-line treatment for stroke prevention in AF is long-term anticoagulation, which has proven efficacy.[Collado FMS, Lama von Buchwald CM, Anderson CK, et.... 10(21): e022274. PMID 34668395] Warfarin, a vitamin K antagonist, is the predominant agent in clinical use. Several newer direct oral anticoagulant (DOAC) agents, including dabigatran, rivaroxaban apixaban, and edoxaban, have received U.S. Food and Drug Administration (FDA) approval for stroke prevention in nonvalvular AF and have demonstrated noninferiority to warfarin in clinical trials. Warfarin requires frequent monitoring and adjustments as well as lifestyle changes; DOACs do not require the frequent monitoring seen with warfarin therapy. While anticoagulation is effective for stroke prevention, it carries an increased risk of bleeding. Reversal agents can be used to counter the effects life-threatening bleeding in individuals using warfarin or DOAC therapy. Such agents carry their own risk of inducing life-threatening thrombosis. For individuals with AF who have a contraindication to warfarin and DOACs, dual antiplatelet therapy with aspirin and clopidogrel is an option for stroke prevention, though it is less protective than either warfarin or DOACs.

The area of the left atrium with the lowest blood flow in AF, and therefore the highest risk of thrombosis, is the left atrial appendage (LAA). The LAA is a small extension of the left atrium that can vary widely in both size and shape (morphology). LAA morphologies are described according to their appearance and include: the chicken wing, which is the most common morphology and features a prominent bend in the dominant lobe; the cactus, characterized by a dominant central lobe with superior and inferior secondary lobes; the windsock, which features one dominant lobe; and the cauliflower, which is the least common morphology and features numerous lobes with none being dominant. It has been estimated that over 90% of left atrial thrombi occur in the LAA. Surgical removal or exclusion of the LAA is often performed in patients with AF who are undergoing open heart surgery. Surgical techniques to exclude the LAA include resection or occlusion through stapling or clipping.[Collado FMS, Lama von Buchwald CM, Anderson CK, et.... 10(21): e022274. PMID 34668395][Rosati F, de Maat GE, Valente MAE, et al. Surgical.... (10): 2865-2872. PMID 34288215]

Percutaneous LAA occlusion is discussed in policy 2.02.26.

Regulatory Status

In June 2010, the AtriClip LAA Exclusion System (Atricure) was cleared for marketing by the U.S. Food and Drug Administration (FDA) through the 510(k) process (K093679). The FDA determined that this device was substantially equivalent to existing devices for occlusion of the LAA. The AtriClip has gone through numerous iterations since 2010, primarily relating to changes in the clip material composition and refinements of the clip applicator. The current FDA cleared indication is unchanged from the original 2010 indication, which states that the AtriClip is indicated for "exclusion of the LAA, performed under direct visualization, in conjunction with other cardiac surgical procedures."[U.S. Food and Drug Administration. AtriClip LAA Ex.... ystem. Accessed June 27, 2022.] The FDA clearance documentation notes that direct visualization “requires that the surgeon is able to see the heart directly, with or without assistance from a camera, endoscope, etc. or other appropriate viewing technologies." As of 2022, AtriCure markets 7 different versions of the AtriClip device, whose use varies according to LAA size and type of concomitant surgical procedure.[AtriCure. AtriClip LAA Exclusion System. Accessed.... ystem. Accessed June 27, 2022.]

Rationale

This evidence review was created in June 2022 with a search of the PubMed database. The most recent literature update was performed through June 15, 2022.

Evidence reviews assess the clinical evidence to determine whether the use of a technology improves the net health outcome. Broadly defined, health outcomes are length of life, quality of life, and ability to function including benefits and harms. Every clinical condition has specific outcomes that are important to patients and to managing the course of that condition. Validated outcome measures are necessary to ascertain whether a condition improves or worsens; and whether the magnitude of that change is clinically significant. The net health outcome is a balance of benefits and harms.

To assess whether the evidence is sufficient to draw conclusions about the net health outcome of a technology, 2 domains are examined: the relevance and the quality and credibility. To be relevant, studies must represent one or more intended clinical use of the technology in the intended population and compare an effective and appropriate alternative at a comparable intensity. For some conditions, the alternative will be supportive care or surveillance. The quality and credibility of the evidence depend on study design and conduct, minimizing bias and confounding that can generate incorrect findings. The randomized controlled trial (RCT) is preferred to assess efficacy; however, in some circumstances, nonrandomized studies may be adequate. Randomized controlled trials are rarely large enough or long enough to capture less common adverse events and long-term effects. Other types of studies can be used for these purposes and to assess generalizability to broader clinical populations and settings of clinical practice.

Population Reference No. 1 Policy Statement

Surgical Left Atrial Appendage Occlusion with the AtriClip Device Concomitant with an Open or Thoracoscopic Cardiac Procedure

Clinical Context and Therapy Purpose

The purpose of surgical left atrial appendage (LAA) occlusion with the AtriClip device in patients with atrial fibrillation (AF) at risk for embolic stroke is to provide a treatment option that is an alternative to or an improvement on existing therapies.

Use of anticoagulants is the first-line therapy for the reduction of the risk of stroke in individuals with AF. Surgical occlusion of the LAA with AtriClip may be a treatment option for those with contraindications or intolerance to anticoagulants, or in those with poor anticoagulant adherence.

The following PICO was used to select literature to inform this review.

Populations

The relevant population(s) of interest are individuals with AF at increased risk for embolic stroke undergoing LAA occlusion concomitant with open or thoracoscopic cardiac surgical procedures.

Interventions

The therapy being considered is surgical LAA occlusion with the AtriClip device.

The efficacy of surgical LAA occlusion performed in conjunction with other cardiac procedures has been assessed in several systematic reviews and a large (N>10,000) observational study, which have generally found surgical LAA occlusion to be associated with a reduction in the risk of stroke or systemic embolism without an increased risk of post-procedural complications.[Ando M, Funamoto M, Cameron DE, et al. Concomitant.... ): 1071-1080.e2. PMID 29628346][Atti V, Anantha-Narayanan M, Turagam MK, et al. Su.... 10(11): 242-249. PMID 30510641][Ibrahim AM, Tandan N, Koester C, et al. Meta-Analy.... 4(8): 1218-1225. PMID 31474327][Friedman DJ, Piccini JP, Wang T, et al. Associatio.... 319(4): 365-374. PMID 29362794] This review focuses on surgical LAA occlusion with AtriClip. This review does not consider the net health benefit of surgical LAA occlusion in general, nor does it address the net health benefit of surgical LAA occlusion techniques other than AtriClip placement.

Comparators

The following therapies are currently being used for the prevention of stroke in individuals with AF at increased risk for embolic stroke: anticoagulation therapy, other surgical LAA occlusion methods, and no occlusion.

Warfarin is the predominant anticoagulant agent in clinical use. Several newer anticoagulant medications, including dabigatran, rivaroxaban apixaban, and edoxaban have received U.S. Food and Drug Administration (FDA) approval for stroke prevention in nonvalvular AF and have demonstrated noninferiority to warfarin in clinical trials. Warfarin requires frequent monitoring and adjustments as well as lifestyle changes; DOACs do not require the frequent monitoring seen with warfarin therapy. While anticoagulation is effective for stroke prevention, it carries an increased risk of bleeding. Reversal agents can be used to counter the effects of life-threatening bleeding in individuals using warfarin or DOAC therapy. Such agents carry their own risk of inducing life-threatening thrombosis.

Surgical LAA occlusion methods other than the AtriClip device include epicardial stapling and excision and suture closure.

Outcomes

The general outcomes of interest are overall survival, morbid events, and treatment-related morbidity. The primary outcome of interest is the rate of ischemic stroke during follow-up, along with rates of systemic embolization, cardiac events, and mortality. Surgical success, defined as complete LAA occlusion, is not a direct health outcome, although evidence on surgical success is reported here as incomplete LAA occlusion, which may be associated with an increased risk of stroke.[Aryana A, Singh SK, Singh SM, et al. Association b.... ; 12(7): 1431-7. PMID 25998141]

Follow-up of 6 to 12 months or longer is required to assess outcomes.

Study Selection Criteria

Methodologically credible studies were selected using the following principles:

• To assess efficacy outcomes, comparative controlled prospective trials were sought, with a preference for RCTs;

• In the absence of such trials, comparative observational studies were sought, with a preference for prospective studies.

• To assess long-term outcomes and adverse events, single-arm studies that capture longer periods of follow-up and/or larger populations were sought.

• Consistent with a 'best available evidence approach,' within each category of study design, studies with larger sample sizes and longer durations were sought.

• Studies with duplicative or overlapping populations were excluded.

Review of Evidence

A number of studies were excluded from this evidence review because they did not specifically assess surgical LAA occlusion with the Atriclip device.[Abrich VA, Narichania AD, Love WT, et al. Left atr.... 53(3): 285-292. PMID 30267182][Blackshear JL, Johnson WD, Odell JA, et al. Thorac.... 42(7): 1249-52. PMID 14522490][Friedman DJ, Piccini JP, Wang T, et al. Associatio.... 319(4): 365-374. PMID 29362794][Fu M, Qin Z, Zheng S, et al. Thoracoscopic Left At.... ; 123(1): 50-56. PMID 30385030][Inoue T, Suematsu Y. Left atrial appendage resecti.... 8; 54(1): 78-83. PMID 29370349][Jiang S, Zhang H, Wei S, et al. Left atrial append.... (12): 3395-3402. PMID 32939788][Kewcharoen J, Shah K, Bhardwaj R, et al. Surgical.... 45(4): 567-570. PMID 35199863][Ohtsuka T, Nonaka T, Hisagi M, et al. Thoracoscopi.... 5(9): 1314-1320. PMID 29803851][Park-Hansen J, Holme SJV, Irmukhamedov A, et al. A.... 2018; 13(1): 53. PMID 29792215][Yao X, Gersh BJ, Holmes DR, et al. Association of.... (20): 2116-2126. PMID 29800182]

Systematic Reviews

Toale et al (2019)[Toale C, Fitzmaurice GJ, Eaton D, et al. Outcomes.... 29(5): 655-662. PMID 31292605] conducted a systematic review assessing outcomes of LAA occlusion using the AtriClip device in individuals with AF either as a concomitant or stand-alone procedure. The review included 11 uncontrolled cohort studies and case series with a total population of 922 individuals (n ranged from 5 to 291; median n=40). Follow-up among the included studies ranged from time of hospital discharge to 4 years (median 1 year). Results from the largest studies (N>100) with the longest duration (>1 year) are discussed below (see Case Series section). The review found a surgical success rate of 97.8% (902/922) based on varying methods of assessing occlusion completion. When stratified according to surgical approach, success rates were slightly lower for AtriClip placement via a thoracoscopic approach (4 studies; 95.3%) than for an open approach (7 studies; 99.2%). This difference was statistically significant (p=.0002). At least one of the thoracoscopic studies[Kurfirst V, Mokracek A, Canadyova J, et al. Epicar.... 7; 25(1): 37-40. PMID 28369643] attributed their lower success rate to a learning curve associated with AtriClip placement (see Case Series, below). In the ≤30 day postoperative period, 20 individuals underwent surgical revision due to bleeding, 4 had a postoperative ischemic stroke and there were 29 deaths. In follow-up >6 months, there were 5 cases of ischemic stroke, and 42 deaths. Among 798 individuals with data, 477 (60%) had discontinued anticoagulant use.

Randomized Controlled Trials

Whitlock et al (2021)[Whitlock RP, Belley-Cote EP, Paparella D, et al. L.... (22): 2081-2091. PMID 33999547] reported the results of The Left Atrial Appendage Occlusion Study (LAAOS) III that randomized 4,811 individuals to LAA occlusion or no occlusion scheduled to undergo to cardiac surgery (Table 2). Following post-randomization exclusions prior to surgery, 2,379 individuals were included in the occlusion group and 2,411 were included in the no occlusion group (N=4,770). Demographic and clinical characteristics for the intervention and control groups were similar at baseline. Indications for cardiac surgery included isolated coronary artery bypass graft (CABG; 21%), isolated valve replacement (23%), or other cardiac surgical procedures (55%). Thirty-three percent of the enrolled population underwent surgical ablation for AF. Data on occlusion method were reported for 71% (1,685/2,379) of those randomized to the occlusion group. Occlusion method was selected by the treating surgeon. Among those with data regarding the occlusion method, 15% underwent LAA occlusion with an epicardial closure device (e.g., AtriClip). The primary outcome was the incidence of ischemic stroke or systemic arterial embolism. The results of the trial are summarized in Table 3. At a mean 3.8 years follow-up, occlusion was associated with a significant reduction in risk of the primary outcome when compared with no occlusion, without an increased risk of post-procedural bleeding or mortality. Occlusion appeared to result in greater risk reduction among those using either DOAC (hazard ratio [HR], 0.54; 95% CI 0.34 to 0.86) or vitamin K antagonist therapy (HR, 0.62; 95% CI, 0.39 to 1.00) at baseline than in those not on anticoagulant therapy (HR, 0.79; 95% CI, 0.56 to 1.12). Anticoagulant use was 83% in the occlusion group and 81% in the no occlusion group at the time of hospital discharge, and the majority of study participants in both groups continued to use anticoagulants at 1- (80% and 79%), 2- (77% and 78%), and 3-year follow-up (75% and 78%). There was no subgroup analysis by occlusion method. Reporting of harms after the perioperative period was limited, but the risk of a major bleeding event (HR, 0.93; 95% CI 0.78 to 1.11), hospitalization for heart failure (HR, 1.13; 95% CI, 0.92 to 1.40), and myocardial infarction (HR, 0.82; 95% CI, 0.57 to 1.18) were similar between occlusion and no occlusion groups.

Table 2. Summary of Key RCT Characteristics

AF: atrial fibrillation; DOAC: direct-acting oral anticoagulant; LAA: left atrial appendage; NR: not reported; RCT: randomized controlled trial.a Data on occlusion method were reported for 1,685 (of 2,379) study participants

Table 3. Summary of Key RCT Results

CI: confidence interval; HR: hazard ratio; OR: odds ratio; RCT: randomized controlled trial; RR: relative risk.a Reoperation within 48 hours of initial surgery

Study relevance and design and conduct limitations are summarized in Tables 4 and 5. The purpose of the study limitations tables is to display notable limitations identified in each study. This information is synthesized as a summary of the body of evidence following each table and provides the conclusions on the sufficiency of evidence supporting the position statement.

The LAAOS III trial had some other important limitations not captured in Tables 4 and 5. Only 15% underwent LAA occlusion with an epicardial closure device (e.g., AtriClip). No subgroup analysis was conducted according to occlusion method. According to the study's authors, this was due to the lack of randomization for occlusion method. Consequently, the study authors noted "we cannot discern from our results whether all surgical closure methods are comparable" and no conclusions about the effectiveness of AtriClip placement relative to other occlusion methods can be drawn from the trial. In addition, due to the lack of an anticoagulant control group, no conclusions can be drawn from the trial about the comparative effectiveness of AtriClip versus first-line therapy (anticoagulants). The fact that ≥75% of study participants were still using anticoagulants up to 3 years following LAA occlusion also limits the applicability of the study results for those individuals with AF and a contraindication to anticoagulant use.

Table 4. Study Relevance Limitations

The study limitations stated in this table are those notable in the current review; this is not a comprehensive gaps assessment. a Population key: 1. Intended use population unclear; 2. Study population is unclear; 3. Study population not representative of intended use; 4, Enrolled populations do not reflect relevant diversity; 5. Other.b Intervention key: 1. Not clearly defined; 2. Version used unclear; 3. Delivery not similar intensity as comparator; 4. Not the intervention of interest (e.g., proposed as an adjunct but not tested as such); 5: Other.c Comparator key: 1. Not clearly defined; 2. Not standard or optimal; 3. Delivery not similar intensity as intervention; 4. Not delivered effectively; 5. Other.d Outcomes key: 1. Key health outcomes not addressed; 2. Physiologic measures, not validated surrogates; 3. Incomplete reporting of harms; 4. Not establish and validated measurements; 5. Clinically significant difference not prespecified; 6. Clinically significant difference not supported; 7. Other.e Follow-Up key: 1. Not sufficient duration for benefit; 2. Not sufficient duration for harms; 3. Other.

Table 5. Study Design and Conduct Limitations

The study limitations stated in this table are those notable in the current review; this is not a comprehensive gaps assessment.a Allocation key: 1. Participants not randomly allocated; 2. Allocation not concealed; 3. Allocation concealment unclear; 4. Inadequate control for selection bias; 5. Other.b Blinding key: 1. Participants or study staff not blinded; 2. Outcome assessors not blinded; 3. Outcome assessed by treating physician; 4. Other.c Selective Reporting key: 1. Not registered; 2. Evidence of selective reporting; 3. Evidence of selective publication; 4. Other.d Data Completeness key: 1. High loss to follow-up or missing data; 2. Inadequate handling of missing data; 3. High number of crossovers; 4. Inadequate handling of crossovers; 5. Inappropriate exclusions; 6. Not intent to treat analysis (per protocol for noninferiority trials); 7. Other.e Power key: 1. Power calculations not reported; 2. Power not calculated for primary outcome; 3. Power not based on clinically important difference; 4. Other.f Statistical key: 1. Analysis is not appropriate for outcome type: (a) continuous; (b) binary; (c) time to event; 2. Analysis is not appropriate for multiple observations per patient; 3. Confidence intervals and/or p values not reported; 4. Comparative treatment effects not calculated; 5. Other.

The AtriClip® Left Atrial Appendage Exclusion Concomitant to Structural Heart Procedures (ATLAS) RCT compared the AtriClip device (n=376) with medical management (standard of care anticoagulant therapy; n=186) in individuals undergoing a valve or CABG procedure.[AtriClip Left Atrial Appendage Exclusion Concomita.... ATLAS). Accessed July 6, 2022.] The study population did not have a history of AF, but had CHA₂DS₂-VASc ≥2 (mean score, 3.4). The study completion date was June 2019. Full study results have not been published, but some 1 year results have been reported on ClinicalTrials.gov. Rates of postoperative AF were similar between AtriClip (47.3%) and medical management (40.3%) groups. Rates were also similar between groups (8.5% vs. 8.6%) for a composite outcome that included thromboembolic and hemorrhagic events (e.g., ischemic or hemorrhagic stroke, transient ischemic attack [TIA], peripheral ischemia, bleeding event). The rate of all-cause mortality in the AtriClip group (5.32%) was more than double that in the medical management group (2.15%). Full publication of these results would provide direct evidence on the effectiveness of AtriClip versus standard of care management with anticoagulation therapy.

Nonrandomized Studies

A retrospective database study conducted by Soltesz et al (2021)[Soltesz EG, Dewan KC, Anderson LH, et al. Improved.... 6(4): 1201-1208. PMID 33491275] compared outcomes in 931 Medicare patients who underwent concomitant CABG and LAA occlusion with AtriClip with 3,279 patients who underwent CABG only without AtriClip placement (Table 6). The study was funded by the AtriClip manufacuter and was designed to assess both health outcomes and resource utilization. Anticoagulant use was not reported and it is unclear if baseline use was similar between the 2 groups. Surgical LAA occlusion with AtriClip was associated with a lower risk of thromboembolism, and a nonsignificant reduction in risk of ischemic stroke. There was no difference between AtriClip occlusion and no occlusion groups in post-surgical mortality (≤90 days), but LAA occlusion with AtriClip was associated with a lower risk of death >90 days post-surgery (Table 7).

Table 6. Summary of Key Observational Comparative Studies

AF: atrial fibrillation; CABG: coronary artery bypass graft; LAA: left atrial appendage.

Table 7. Summary of Key Observational Comparative Study Results

CI: confidence interval; HR: hazard ratio; NR: not reported; sHR: subhazard ratioa Proportions represent annual risk, not absolute event rates

Case Series

As noted above, the 2019 Toale et al[Toale C, Fitzmaurice GJ, Eaton D, et al. Outcomes.... 29(5): 655-662. PMID 31292605] systematic review included 11 uncontrolled cohort studies or case series of AtriClip placement either as a concomitant or stand-alone procedure. Of the 11 studies in the review, 2 studies[Caliskan E, Sahin A, Yilmaz M, et al. Epicardial l.... 0(7): e105-e114. PMID 29016813][Kurfirst V, Mokracek A, Canadyova J, et al. Effect.... ugust 2017; 59(4): e376-e380. ] included >100 individuals who had AtriClip placement concomitant to cardiac surgery with follow-up of a year or more (Table 8). Both studies found AtriClip placement associated with successful occlusion rates ≥98% and stroke rates ≤1% in the postoperative period and ≤2% in the long-term follow-up (Table 9). Kurfirst et al (2017)[Kurfirst V, Mokracek A, Canadyova J, et al. Effect.... ugust 2017; 59(4): e376-e380. ] attributed their less than 100% success rate to a learning curve associated with AtriClip placement; 2 of the 3 failures were among the first 10 cases receiving AtriClip placement.

Table 8. Summary of Key Case Series Characteristics

AF: atrial fibrillation; CABG: coronary artery bypass graft; DOAC: direct-acting oral anticoagulants; NR: not reported.a 4.5% (7/155) underwent AtriClip placement as a stand-alone procedure

Table 9. Summary of Key Case Series Results

NR: not reported.

Section Summary: Surgical Left Atrial Appendage Occlusion with the AtriClip Device Concomitant With an Open or Thoracoscopic Cardiac Procedure

Evidence comparing surgical LAA occlusion with an AtriClip device with anticoagulation, another surgical occlusion method, or no occlusion in individuals undergoing concomitant cardiac procedures is limited. LAA occlusion was associated with a reduced risk of stroke versus no occlusion in the LAAOS III trial, but the trial was not designed to assess the net health benefit of LAA occlusion with an AtriClip device specifically, nor was it designed to assess whether surgical LAA occlusion is suitable as a replacement for long-term anticoagulant use. An industry sponsored retrospective database study that compared LAA occlusion with AtriClip with no occlusion found that AtriClip placement was associated with a lower risk of ischemic stroke that was not statistically significant, and a reduced risk of thromboembolism that was of marginal statistical significance. Large (N>100) case series with 2- to 3- years follow-up reported stroke rates ≤1% in the postoperative period and ≤2% in the long-term follow-up. Well-designed RCTs with follow-up of 1 year or more comparing AtriClip with anticoagulation, another surgical occlusion method, and/or no occlusion are needed to provide adequate evidence for assessment of net health benefit.

For individuals with AF at increased risk for embolic stroke undergoing LAA occlusion with an AtriClip device concomitant with open or thoracoscopic cardiac surgical procedures, the evidence includes a RCT, a controlled observational study, and case series. Relevant outcomes are ischemic stroke, cardiac events, and mortality. Although evidence from several systematic reviews and a large (N>10,000) observational study found surgical LAA occlusion was associated with a reduction in the risk of stroke without an increase in the risk of adverse events, direct evidence specifically comparing the AtriClip Left Atrial Appendage Exclusion System with anticoagulation, another surgical occlusion method, or no occlusion is limited. LAA occlusion was associated with a reduced risk of stroke versus no occlusion in the LAAOS III trial, but the trial was not designed to specifically assess the net health benefit of LAA occlusion with an AtriClip device. A retrospective database study that compared the AtriClip device with no occlusion found that AtriClip placement was associated with a lower risk of ischemic stroke, which was not statistically significant, and a reduced risk of thromboembolism that was of marginal statistical significance. Large (N>100) case series of AtriClip device use with 2- to 3- years follow-up reported stroke rates ≤1% in the postoperative period and ≤2% in the long-term follow-up. Well-designed RCTs with follow-up of 1 year or more comparing the AtriClip device with anticoagulation, other surgical occlusion methods, and/or no occlusion are needed to provide adequate evidence for assessment of net health benefit. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

Population Reference No. 2 Policy Statement

Surgical Left Atrial Appendage Occlusion with the AtriClip Device as a Stand-Alone Procedure

Clinical Context and Therapy Purpose

The purpose of surgical LAA occlusion with AtriClip in patients with AF at risk for embolic stroke is to provide a treatment option that is an alternative to or an improvement on existing therapies.

As noted above, use of anticoagulants is the first-line therapy for the reduction of the risk of stroke in individuals with AF. Surgical occlusion of the LAA with AtriClip may be a treatment option for those with contraindications or intolerance to anticoagulants, or in those with poor anticoagulant adherence.

The following PICO was used to select literature to inform this review.

Populations

The relevant population(s) of interest are individuals with AF at increased risk for embolic stroke undergoing LAA occlusion as a stand-alone procedure.

Interventions

The therapy being considered is surgical LAA occlusion with the AtriClip device.

The efficacy of surgical LAA occlusion performed in conjunction with other cardiac procedures has been assessed in several systematic reviews and a large (N>10,000) observational study, which have generally found surgical LAA occlusion to be associated with a reduction in the risk of stroke or systemic embolism without an increased risk of post-procedural complications.[Ando M, Funamoto M, Cameron DE, et al. Concomitant.... ): 1071-1080.e2. PMID 29628346][Atti V, Anantha-Narayanan M, Turagam MK, et al. Su.... 10(11): 242-249. PMID 30510641][Ibrahim AM, Tandan N, Koester C, et al. Meta-Analy.... 4(8): 1218-1225. PMID 31474327][Friedman DJ, Piccini JP, Wang T, et al. Associatio.... 319(4): 365-374. PMID 29362794] This review focuses on surgical LAA occlusion with AtriClip. This review does not consider the net health benefit of surgical LAA occlusion in general, nor does it address the net health benefit of surgical LAA occlusion techniques other than AtriClip placement.

Comparators

The following therapies are currently being used for the prevention of stroke in individuals with AF at increased risk for embolic stroke: anticoagulation therapy or percutaneous LAA occlusion.

Warfarin is the predominant anticoagulant agent in clinical use. Several newer anticoagulant medications, including dabigatran, rivaroxaban apixaban, and edoxaban have received U.S. FDA approval for stroke prevention in nonvalvular AF and have demonstrated noninferiority to warfarin in clinical trials. Warfarin requires frequent monitoring and adjustments as well as lifestyle changes; DOACs do not require the frequent monitoring seen with warfarin therapy. While anticoagulation is effective for stroke prevention, it carries an increased risk of bleeding. Reversal agents can be used to counter the effects of life-threatening bleeding in individuals using warfarin or DOAC therapy. Such agents carry their own risk of inducing life-threatening thrombosis.

Percutaneous LAA occlusion devices have been developed as a nonpharmacologic alternative for stroke prevention in AF. These devices are delivered through a catheter guided by transesophageal echocardiography or fluoroscopy. Percutaneous LAA occlusion requires the use of anticoagulation therapy during the perioperative period, followed by antiplatelet therapy. Percutaneous LAA occlusion devices are further discussed in policy 2.02.26.

Outcomes

The general outcomes of interest are overall survival, morbid events, and treatment-related morbidity. The primary outcome of interest is the rate of ischemic stroke during follow-up, along with rates of systemic embolization, cardiac events, and mortality. Surgical success, defined as complete LAA occlusion, is not a direct health outcome, although evidence on surgical success is reported here as incomplete LAA occlusion may be associated with an increased risk of stroke.[Aryana A, Singh SK, Singh SM, et al. Association b.... ; 12(7): 1431-7. PMID 25998141]

Follow-up of 6 to 12 months or longer is required to assess outcomes.

Study Selection Criteria

Methodologically credible studies were selected using the following principles:

• To assess efficacy outcomes, comparative controlled prospective trials were sought, with a preference for RCTs;

• In the absence of such trials, comparative observational studies were sought, with a preference for prospective studies.

• To assess long-term outcomes and adverse events, single-arm studies that capture longer periods of follow-up and/or larger populations were sought.

• Consistent with a 'best available evidence approach,' within each category of study design, studies with larger sample sizes and longer durations were sought.

• Studies with duplicative or overlapping populations were excluded.

Review of Evidence

Nonrandomized Studies

Branzoli et al (2022)[Branzoli S, Guarracini F, Marini M, et al. Heart T.... 29 2021; 11(1). PMID 35011916] conducted a retrospective cohort study of 40 individuals with AF and a contraindication to anticoagulant use managed by a Heart Team. Participants had a mean age of 74 years, 35% were female and had a mean CHA₂DS₂VASc score of 5.1 at baseline. Between 2017 and 2020, 20 individuals underwent surgical (thoracoscopic) LAA occlusion with the AtriClip device and 20 received percutaneuous LAA occlusion with the Watchman device. Perioperative outcomes (procedure duration, length of hospital stay) were similar between groups with no serious adverse events or deaths. At a mean follow-up of 33 months, there were no instances of hospitalization due to cardiovascular or neurological events in either group.

Case Series

Cartledge et al (2022),[Cartledge R, Suwalski G, Witkowska A, et al. Stand.... 34(4): 548-555. PMID 34871377] and Franciulli et al (2020)[Franciulli M, De Martino G, Librera M, et al. Stan.... 15(6): 541-546. PMID 33048625] reported on the use of AtriClip as a stand-alone LAA occlusion procedure in individuals at high-risk of stroke (Table 10). In both studies, AtriClip placement was achieved via a thoracoscopic approach. LAA occlusion was successful in nearly all cases, with few post-procedural events. No incidence of stroke was reported in either study after 6-months or 1-year follow-up (Table 11). There were 6 deaths in the Cartledge et al study after 1-year, but study authors deemed none device or procedure related.

Table 10. Summary of Key Case Series Characteristics

AF: atrial fibrillation; TIA: transient ischemic attack

Table 11. Summary of Key Case Series Results

NR: not reported

Section Summary: Surgical Left Atrial Appendage Occlusion with the AtriClip Device as a Stand-Alone Procedure

Evidence on surgical LAA occlusion with the AtriClip device as a stand-alone procedure is limited. One small (N=40) retrospective observational study found use of AtriClip as a stand-alone procedure resulted in similar outcomes as percutaneous LAA occlusion; the evidence is too limited to draw definitive conclusions. Well-designed RCTs with follow-up of 1 year or more comparing AtriClip LAA occlusion with anticoagulants or percutaneous LAA occlusion are needed to provide adequate evidence for the assessment of net health benefit. The ongoing SALAMANDER study (NCT05144958; completion anticipated in 2025) should provide direct comparative evidence of stand-alone AtriClip LAA occlusion with percutaneous occlusion when published.

For individuals with AF at increased risk for embolic stroke undergoing LAA occlusion with an AtriClip device as a stand-alone procedure, the evidence includes a controlled observational study and case series. Relevant outcomes are ischemic stroke, cardiac events, and mortality. One small (N=40) industry sponsored retrospective observational study reported that use of the AtriClip device as a stand-alone procedure resulted in similar outcomes compared to percutaneous LAA occlusion. This evidence is too limited to draw definitive conclusions. Well-designed RCTs with follow-up of 1 year or more comparing stand-alone AtriClip device placement with percutaneous LAA occlusion are needed to provide adequate evidence for assessment of net health benefit. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

Summary of Evidence

For individuals with AF at increased risk for embolic stroke undergoing LAA occlusion with an AtriClip device concomitant with open or thoracoscopic cardiac surgical procedures, the evidence includes a RCT, a controlled observational study, and case series. Relevant outcomes are ischemic stroke, cardiac events, and mortality. Although evidence from several systematic reviews and a large (N>10,000) observational study found surgical LAA occlusion was associated with a reduction in the risk of stroke without an increase in the risk of adverse events, direct evidence specifically comparing the AtriClip Left Atrial Appendage Exclusion System with anticoagulation, another surgical occlusion method, or no occlusion is limited. LAA occlusion was associated with a reduced risk of stroke versus no occlusion in the LAAOS III trial, but the trial was not designed to specifically assess the net health benefit of LAA occlusion with an AtriClip device. A retrospective database study that compared the AtriClip device with no occlusion found that AtriClip placement was associated with a lower risk of ischemic stroke, which was not statistically significant, and a reduced risk of thromboembolism that was of marginal statistical significance. Large (N>100) case series of AtriClip device use with 2- to 3- years follow-up reported stroke rates ≤1% in the postoperative period and ≤2% in the long-term follow-up. Well-designed RCTs with follow-up of 1 year or more comparing the AtriClip device with anticoagulation, other surgical occlusion methods, and/or no occlusion are needed to provide adequate evidence for assessment of net health benefit. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

For individuals with AF at increased risk for embolic stroke undergoing LAA occlusion with an AtriClip device as a stand-alone procedure, the evidence includes a controlled observational study and case series. Relevant outcomes are ischemic stroke, cardiac events, and mortality. One small (N=40) industry sponsored retrospective observational study reported that use of the AtriClip device as a stand-alone procedure resulted in similar outcomes compared to percutaneous LAA occlusion. This evidence is too limited to draw definitive conclusions. Well-designed RCTs with follow-up of 1 year or more comparing stand-alone AtriClip device placement with percutaneous LAA occlusion are needed to provide adequate evidence for assessment of net health benefit. The evidence is insufficient to determine that the technology results in an improvement in the net health outcome.

Supplemental Information

The purpose of the following information is to provide reference material. Inclusion does not imply endorsement or alignment with the evidence review conclusions.

Practice Guidelines and Position Statements

Guidelines or position statements will be considered for inclusion in ‘Supplemental Information' if they were issued by, or jointly by, a US professional society, an international society with US representation, or National Institute for Health and Care Excellence (NICE). Priority will be given to guidelines that are informed by a systematic review, include strength of evidence ratings, and include a description of management of conflict of interest.

American Heart Association et al

In 2019, the American Heart Association, in conjunction with the American College of Cardiology and the Heart Rhythm Society, issued a focused update of their 2014 joint guideline on the management of individuals with atrial fibrillation (AF).[January CT, Wann LS, Calkins H, et al. 2019 AHA/AC.... 16(8): e66-e93. PMID 30703530] The focused update states that "surgical occlusion of the LAA may be considered in patients with AF undergoing cardiac surgery as a component of an overall heart team approach to the management of AF" (Class IIB [weak evidence of benefit outweighing risk]; Level B-NR [moderate-quality evidence from nonrandomized studies or meta-analyses of those studies]). No recommendation was made regarding the method of surgical LAA occlusion.

American College of Chest Physicians

Guidance from the American College of Chest Physicians in 2018[Lip GYH, Banerjee A, Boriani G, et al. Antithrombo.... 4(5): 1121-1201. PMID 30144419] recommends:

• In patients with AF at high risk of ischemic stroke who have absolute contraindications for oral anticoagulants (OAC), we suggest using LAA occlusion (weak recommendation, low quality evidence).
• In AF patients at risk of ischemic stroke undergoing cardiac surgery, we suggest considering surgical exclusion of the LAA for stroke prevention, but the need for long-term OAC is unchanged (weak recommendation, low quality evidence).

Neither statement recommends a specific occlusion method or approach.

U.S. Preventive Services Task Force Recommendations

No U.S. Preventive Services Task Force (USPSTF) recommendations for surgical LAA occlusion have been identified.

Medicare National Coverage

There is no national coverage determination. In the absence of a national coverage determination, coverage decisions are left to the discretion of local Medicare carriers.

Ongoing and Unpublished Clinical Trials

Some currently unpublished trials that might influence this review are listed in Table 12.

Table 12. Summary of Key Trials

NCT: national clinical trial.a Denotes industry-sponsored or cosponsored trial.

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Codes

Applicable Modifiers

Policy History