Percutaneous Left Atrial Appendage Closure Devices for Stroke Prevention in Atrial Fibrillation

POLICY NUMBER

A.2.02.26

DESCRIPTION

Stroke prevention in patients with atrial fibrillation is an important goal of treatment. Treatment with anticoagulant medications is the most common approach to stroke prevention. Most embolic strokes originate from the left atrial appendage; therefore, occlusion of the left atrial appendage may offer a nonpharmacologic alternative to anticoagulant medications to lower the risk of stroke. Multiple percutaneously deployed devices are being investigated for left atrial appendage closure (LAAC). Two types of left atrial appendage devices (the Watchman and Amplatzer Amulet devices) have approval from the U.S. Food and Drug Administration (FDA) for stroke prevention in patients with atrial fibrillation.

Atrial Fibrillation and Stroke

Atrial fibrillation is the most common type of irregular heartbeat, affecting at least 2.7 million people in the U.S. Risk of atrial fibrillation has been found to be lower in Black, Hispanic and Asian patients relative to White patients, including following adjustment for demographic and atrial fibrillation risk factors. Stroke is the most serious complication of atrial fibrillation. The estimated incidence of stroke in non-treated patients with atrial fibrillation is 5% per year; despite a lower risk of atrial fibrillation, Black and Hispanic patients have an increased risk of stroke compared with White patients. Stroke associated with atrial fibrillation 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 a main goal of atrial fibrillation treatment.

Stroke in atrial fibrillation occurs primarily as a result of thromboembolism from the left atrium. The lack of atrial contractions in atrial fibrillation leads to blood stasis in the left atrium, and this low flow state increases the risk for thrombosis. The area of the left atrium with the lowest blood flow in atrial fibrillation, and, therefore, the highest risk of thrombosis is the left atrial appendage (LAA). It has been estimated that 90% of left atrial thrombi occur in the LAA.

Treatment

PharmacologicThe main treatment for stroke prevention in atrial fibrillation is anticoagulation, which has proven efficacy. The risk for stroke among patients with atrial fibrillation is evaluated using several factors. Two commonly used scores, the CHADS₂ score and the CHA₂DS₂-VAScscore are described in the table below. Warfarin or newer anticoagulant medications, including dabigatran, rivaroxaban, apixaban, and edoxaban are options for stroke prevention. In nonvalvular AF, newer anticoagulants have demonstrated noninferiority to warfarin in clinical trials. While anticoagulation is effective for stroke prevention, it carries an increased risk of bleeding. Also, warfarin requires frequent monitoring and adjustments as well as lifestyle changes. Newer agents do not require the frequent monitoring seen with warfarin therapy. The 2018 American College of Chest Physicians guidelines (updated from 2012) recommend that CHA₂DS₂VASc be used to evaluate stroke risk, and patients initially identified as having a low stroke risk should not be given antithrombotic therapy. In addition, they recommend bleeding risk assessments be given to every patient at every patient contact and that "potentially modifiable bleeding risk factors" should be the initial focus.

CHADS₂ and CHA₂DS₂-VASc Scores to Predict Ischemic Stroke Risk in Patients with Atrial Fibrillation

Bleeding is the primary risk associated with systemic anticoagulation. Risk scores have been developed to estimate the risk of significant bleeding in patients treated with systemic anticoagulation, such as the HAS-BLED score, which has been validated to assess the annual risk of significant bleeding in patients with atrial fibrillation treated with warfarin. The score ranges from 0 to 9, based on clinical characteristics, including the presence of hypertension, renal and liver function, history of stroke, bleeding, labile international normalized ratios, age, and drug/alcohol use. Scores of 3 or greater are considered to be associated with high risk of bleeding, potentially signaling the need for closer monitoring of patients for adverse risks, closer monitoring of international normalized ratios, or differential dose selections of oral anticoagulants or aspirin.

SurgerySurgical removal, or exclusion, of the LAA is often performed in patients with atrial fibrillation who are undergoing open heart surgery for other reasons. Percutaneous left atrial appendage closure (LAAC) devices have been developed as a nonpharmacologic alternative to anticoagulation for stroke prevention in atrial fibrillation. The devices may prevent stroke by occluding the LAA, thus preventing thrombus formation.

Several versions of LAA occlusion devices have been developed. The PLAATO system (ev3 Endovascular) was the first device to be approved by the FDA for LAA occlusion. The device was discontinued in 2007 for commercial reasons, and intellectual property was sold to manufacturers of the Watchman system. The Watchman Left Atrial Appendage System (Boston Scientific) is a self-expanding nickel titanium device. It has a polyester covering and fixation barbs for attachment to the endocardium. Implantation is performed percutaneously through a catheter delivery system, using venous access and transseptal puncture to enter the left atrium. Transesophageal echocardiography and fluoroscopy are used to guide the procedure. Following implantation, patients receive anticoagulation with warfarin or alternate agents for approximately 1 to 2 months. After this period, patients are maintained on antiplatelet agents (i.e., aspirin and/or clopidrogel) indefinitely. The Watchman FLX device is a next-generation Watchman device that is also FDA-approved for LAAC. This device is based on the design of the Watchman device, is fully recapturable and repositionable, and was made to occlude a wider size range of LAA than the original Watchman device. The Amplatzer cardiac plug (St. Jude Medical), is FDA-approved for closure of atrial septal defects, but not for LAAC. A second-generation device developed for the specific indication of LAAC, the Amplatzer Amulet (Abbott), received FDA approval in August 2021. The Amplatzer Amulet consists of a nitinol mesh disc to seal the ostium of the LAA and a nitinol mesh distal lobe, to be positioned within the LAA. The device is preloaded within a delivery sheath. The Percutaneous LAA Transcatheter Occlusion device (ev3) has also been evaluated in research studies but has not received FDA approval.

The Lariat Loop Applicator is a suture delivery device approved by the FDA, intended to close a variety of surgical wounds. It is not specifically approved for LAAC. While the Watchman and other devices are implanted in the endocardium, the Lariat is a non-implant epicardial device.

In September 2021, the FDA sent a letter to healthcare providers indicating that women undergoing percutaneous LAA closure may be at higher risk of adverse procedural outcomes than men. This was based on an analysis of registry data from 49,357 patients who underwent LAA closure with the Watchman device. When adjusted for multiple confounding factors, the study found women were more likely than men to experience any adverse event, major adverse events, and major bleeding. Women also had a significantly higher risk of death (adjusted odds ratio [OR], 2.01; 95% confidence interval [CI] 1.31 to 3.09) but absolute risk was low for both women and men (0.3% vs. 0.1%). In their letter, the FDA stated that they believe the benefits continue to outweigh the risks for approved LAA closure devices when used in accordance with their instructions for use.

Outcome Measures

The optimal study design for evaluating the efficacy of percutaneous LAAC for the prevention of stroke in atrial fibrillation is a randomized controlled trial that includes clinically relevant measures of health outcomes. The rate of ischemic stroke during follow-up is the primary outcome of interest, along with rates of systemic embolization, cardiac events, bleeding complications, and death. For the LAAC devices, the appropriate comparison group could be oral anticoagulation, no therapy (for patients who have a prohibitive risk for oral anticoagulation), or open surgical repair.

Ideally, percutaneous LAAC devices would represent an alternative to oral anticoagulation for the prevention of stroke in patients with atrial fibrillation. However, during the postimplantation period, the LAAC device may be associated with increased thrombogenicity, therefore, anticoagulation is used during the periprocedural period. Most studies evaluating percutaneous LAAC devices have included patients who are eligible for anticoagulation.

In 2002, the PLAATO system (ev3 Endovascular) was the first device to be approved by the FDA for LAA occlusion. The device was discontinued in 2007 for commercial reasons, and intellectual property was sold to manufacturers of the Watchman system.

In 2015, the Watchman™ Left Atrial Appendage Closure Technology (Boston Scientific) was approved by the U.S. Food and Drug Administration (FDA) through the premarket approval process by the Left Atrial Appendage Versus Warfarin Therapy for Prevention of Stroke in Patients with Atrial Fibrillation randomized controlled trial. In 2020, the Watchman FLX device (Boston Scientific) was approved by the FDA based on the single-arm, nonrandomized PINNACLE FLX study. The Amplatzer™ Amulet™ Left Atrial Appendage Occluder (Abbott) received FDA approval in 2021 through the premarket approval process based on results from the Amplatzer Amulet Left Atrial Appendage Occluder Randomized Controlled Trial (Amulet IDE Trial). The Watchman and Amplatzer Amulet devices are indicated to reduce the risk of thromboembolism from the left atrial appendage (LAA) in individuals with nonvalvular atrial fibrillation who:

• Are at increased risk for stroke and systemic embolism based on CHADS₂ or CHA₂DS₂-VASc scores and are recommended for anticoagulation therapy;

• Are deemed by their physicians to be suitable for anticoagulation therapy; and

• Have an appropriate rationale to seek a nonpharmacologic alternative to anticoagulation therapy, taking into account the safety and effectiveness of the device compared to anticoagulation therapy.

FDA product code: NGV.

Several other devices are being evaluated for LAA occlusion, but are not approved in the United States for percutaneous LAAC. In 2006, the Lariat™ Loop Applicator device (SentreHEART [now AtriCure]), a suture delivery system, was cleared for marketing by the FDA through the 510(k) process. The intended use is to facilitate suture placement and knot tying in surgical applications where soft tissues are being approximated or ligated with a pretied polyester suture. The Amplatzer Cardiac Plug device (St. Jude Medical [now Abbott]) and WaveCrest™ (Johnson & Johnson Biosense Webster) have CE approval in Europe for LAAC, but are not currently approved in the United States for this indication.

POLICY

The use of a device with U.S. Food and Drug Administration (FDA) approval for percutaneous left atrial appendage closure (e.g., the Watchman or Amplatzer Amulet) may be considered medically necessary for the prevention of stroke in individuals with atrial fibrillation when the following criteria are met:

• There is an increased risk of stroke and systemic embolism based on CHADS₂ or CHA₂DS₂-VASc score and systemic anticoagulation therapy is recommended; AND

• The long-term risks of systemic anticoagulation outweigh the risks of the device implantation (see Policy Guidelines).

The use of a device with FDA approval for percutaneous left atrial appendage closure (e.g., the Watchman or Amplatzer Amulet) for stroke prevention in individuals who do not meet the above criteria is considered investigational.

The use of other percutaneous left atrial appendage closure devices, including but not limited to the Lariat and Amplatzer Cardiac Plug devices, for stroke prevention in individuals with atrial fibrillation is considered investigational.

POLICY EXCEPTIONS

None 

POLICY GUIDELINES

The coverage guidelines outlined in the Medical Policy Manual should not be used in lieu of the Member's specific benefit plan language.

The balance of risks and benefits associated with percutaneous implantation of the Watchman or Amplatzer Amulet device for stroke prevention, as an alternative to systemic anticoagulation, must be made on an individual basis. 

Bleeding is the primary risk associated with systemic anticoagulation. A number of risk scores have been developed to estimate the risk of significant bleeding in individuals treated with systemic anticoagulation. An example is the HAS-BLED score, which is validated to assess the annual risk of significant bleeding in individuals with atrial fibrillation treated with warfarin. Scores range from 0 to 9, based on a number of clinical characteristics (see the table below).

Clinical Components of the HAS-BLED Bleeding Risk Score

HAS-BLED: Hypertension, Abnormal renal/liver function, Stroke, Bleeding history or predisposition, Labile INR (international normalized ratio), Elderly, Drugs/alcohol concomitantly.

The risk of major bleeding in individuals with scores of 3, 4, and 5 has been reported at 3.74 per 100 patient-years, 8.70 per 100 patient-years, and 12.5 per 100 patient-years, respectively. Scores of 3 or greater are considered to be associated with a high risk of bleeding, potentially signaling the need for closer monitoring of individuals for adverse events, closer monitoring of international normalized ratio, or differential dose selections of oral anticoagulants or aspirin.

Medically Necessary is defined as those services, treatments, procedures, equipment, drugs, devices, items or supplies furnished by a covered Provider that are required to identify or treat a Member's illness, injury or Mental Health Disorders, and which Company determines are covered under this Benefit Plan based on the criteria as follows in A through D:

A.  consistent with the symptoms or diagnosis and treatment of the Member's condition, illness, or injury; and

B.  appropriate with regard to standards of good medical practice; and

C.  not solely for the convenience of the Member, his or her Provider; and

D.  the most appropriate supply or level of care which can safely be provided to Member. When applied to the care of an Inpatient, it further means that services for the Member's medical symptoms or conditions require that the services cannot be safely provided to the Member as an Outpatient.

For the definition of medical necessity, “standards of good medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. BCBSMS makes no payment for services, treatments, procedures, equipment, drugs, devices, items or supplies which are not documented to be Medically Necessary. The fact that a Physician or other Provider has prescribed, ordered, recommended, or approved a service or supply does not in itself, make it Medically Necessary.

Investigative is defined as the use of any treatment procedure, facility, equipment, drug, device, or supply not yet recognized as a generally accepted standard of good medical practice for the treatment of the condition being treated and; therefore, is not considered medically necessary. For the definition of Investigative, “generally accepted standards of medical practice” means standards that are based on credible scientific evidence published in peer-reviewed medical literature generally recognized by the relevant medical community, and physician specialty society recommendations, and the views of medical practitioners practicing in relevant clinical areas and any other relevant factors. In order for equipment, devices, drugs or supplies [i.e, technologies], to be considered not investigative, the technology must have final approval from the appropriate governmental bodies, and scientific evidence must permit conclusions concerning the effect of the technology on health outcomes, and the technology must improve the net health outcome, and the technology must be as beneficial as any established alternative and the improvement must be attainable outside the testing/investigational setting.

POLICY HISTORY

07/29/2011: Approved by Medical Policy Advisory Committee. 

04/26/2012: Policy reviewed; added "percutaneous" to the policy title and policy statement.

07/19/2013: Policy reviewed; no changes to policy statement. Added CPT code 0281T to the Code Reference section.

09/15/2014: Policy reviewed; no changes.

08/18/2015: Code Reference section updated for ICD-10.

02/01/2016: Policy description updated regarding anticoagulant medications and devices. Added policy statement that the use of a device with FDA approval for percutaneous left atrial appendage closure may be considered medically necessary for the prevention of stroke in patients with atrial fibrillation when certain criteria are met. Added policy statement that the use of an FDA-approved device for patients not meeting the criteria is considered investigational. Policy statement revised to state that the use of other percutaneous left atrial appendage closure devices, including but not limited to the Lariat, PLAATO, and Amplatzer devices, for stroke prevention in patients with atrial fibrillation is considered investigational. Policy guidelines updated regarding clinical components of the HAS-BLED bleeding risk score. Added medically necessary and investigative definitions. Code Reference section updated to change "Investigational Codes" to "Medically Necessary Codes." Code Reference section updated to add CPT code 33999 and ICD-10 diagnosis codes I48.0, I48.1, I48.2, and I48.91.

06/06/2016: Policy number A.2.02.26 added.

08/16/2016: Policy description updated. Policy statements unchanged.

12/30/2016: Code Reference section updated to add new 2017 CPT code 33340.

06/19/2017: Policy description updated regarding devices. Policy statements unchanged.

06/12/2018: Policy description updated regarding ischemic stroke risk and outcome measures. Last investigational policy statement updated to remove the PLAATO device. Code Reference section updated to remove deleted CPT code 0281T.

06/05/2019: Policy description updated regarding atrial fibrillation and devices. Policy statements unchanged.

09/23/2019: Code Reference section updated to add new ICD-10 diagnosis codes I48.11, I48.19, I48.20, and I48.21, effective 10/01/2019.

06/16/2020: Policy description updated regarding treatment. Policy statements unchanged.

07/27/2021: Policy description updated regarding treatment and devices. Policy statements unchanged. Policy Guidelines updated to change "Nervous/Mental Conditions" to "Mental Health Disorders" and "Medically Necessary" to "medical necessity." Code Reference section updated to remove deleted ICD-10 diagnosis codes I48.1 and I48.2.

11/01/2022: Policy description updated regarding atrial fibrillation, stroke, surgery, and devices. Policy statements and Policy Guidelines updated to include the FDA-approved Amplatzer Amulet device. Investigational statement regarding the use of other percutaneous left atrial appendage closure devices updated to change "Amplatzer devices" to "Amplatzer Cardiac Plug devices."

06/07/2023: Policy description updated. Policy statements and Policy Guidelines updated to change "patients" to "individuals."

06/12/2024: Policy description and Policy Guidelines updated to change "patients" to "individuals." Policy statements unchanged.

08/08/2025: Policy description updated regarding devices and treatment for atrial fibrillation and stroke. Policy statements unchanged.

SOURCE(S)

Blue Cross Blue Shield Association policy # 2.02.26 

CODE REFERENCE

This may not be a comprehensive list of procedure codes applicable to this policy.

The code(s) listed below are ONLY medically necessary if the procedure is performed according to the "Policy" section of this document. 

Medically Necessary Codes

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