Durable Medical Equipment Section - Wearable Cardioverter-Defibrillators and Automatic External Defibrillators for Home Use

IMPORTANT REMINDER

This Medical Policy has been developed through consideration of medical necessity, generally accepted standards of medical practice, and review of medical literature and government approval status.

Benefit determinations should be based in all cases on the applicable contract language. To the extent there are any conflicts between these guidelines and the contract language, the contract language will control.

The purpose of medical policy is to provide a guide to coverage. Medical Policy is not intended to dictate to providers how to practice medicine. Providers are expected to exercise their medical judgment in providing the most appropriate care.

Description

Sudden cardiac arrest (SCA) is the most common cause of death in patients with coronary artery disease. The automatic implantable cardioverter defibrillator (AICD) has proven effective in reducing mortality for survivors of SCA and for patients with documented malignant ventricular arrhythmias. More recently, the use of AICDs has been potentially broadened by studies reporting a reduction in mortality for patients at risk for ventricular arrhythmias, such as patients with prior myocardial infarction (MI) and reduced ejection fraction. AICDs consist of implantable leads in the heart that connect to a pulse generator implanted beneath the skin of the chest or abdomen. In the past AICD placement required a thoracotomy, but current technology allows implantation with only a minor surgical procedure, with the cardiac leads placed percutaneously. Potential adverse effects of AICD placement are bleeding, infection, pneumothorax, and delivery of unnecessary countershocks.

The wearable cardioverter-defibrillator (WCD) is an external device that is intended to perform the same tasks as an AICD, without requiring any invasive procedures. It consists of a vest that is worn continuously underneath the patient's clothing. Part of this vest is the "electrode belt" that contains the cardiac monitoring electrodes and the therapy electrodes that deliver a countershock. The vest is connected to a monitor with a battery pack and alarm module that is worn on the patient's belt. The monitor contains the electronics that interpret the cardiac rhythm and determine when a countershock is necessary. The alarm module alerts the patient to certain conditions by lights or voice messages. The U.S. Food and Drug Administration (FDA) approved the Lifecor WCD® 2000 system via premarket application approval in December 2001 for "adult patients who are at risk for cardiac arrest and are either not candidates for or refuse an implantable defibrillator."

An automatic external defibrillator (AED) is a compact, portable device that is used to deliver an electrical shock to a victim of SCA. AED units use a microprocessor inside a portable defibrillator to interpret a victim's heart rhythm through adhesive electrodes. The computer recognizes ventricular fibrillation (VF) or ventricular tachycardia (VT) and either advises the operator that electrical defibrillation is needed or automatically delivers a countershock.

Policy/Criteria

Wearable Cardioverter Defibrillators

1. Wearable Cardioverter Defibrillators
   1. Use of wearable cardioverter-defibrillators for the prevention of sudden cardiac death is considered medically necessary as interim treatment  for patients who require an implantable cardioverter defibrillator (ICD) but have a temporary contraindication, such as systemic infection, which is expected to resolve.
   2. Use of wearable cardioverter-defibrillators for the prevention of sudden cardiac death is considered investigational for all other indications including, but not limited to permanent placement or use immediately (i.e. less than 40 days) following an acute myocardial infarction.
2. Automatic external defibrillators for use in the home are considered investigational.

Scientific Background

Wearable Cardioverter Defibrillators

There is general consensus among experts that the appropriate end-point for studies of AICDs is total mortality. (2) There are few peer-reviewed published studies that report on clinical outcomes of WCDs and no studies that evaluate the efficacy of WCDs in reducing mortality compared to alternatives. Only one full-length English manuscript was identified in the peer-reviewed literature. (3) This study included 15 survivors of sudden cardiac arrest (SCA) and evaluated the ability of the WCD to identify and convert arrhythmias induced in the electrophysiology lab. Of the 15 patients, 10 had inducible ventricular tachycardia or ventricular fibrillation. The WCD correctly sensed the arrhythmia in 9 of 10 cases, and delivered a successful countershock in all 9 cases that were detected.

The FDA approved the Lifecor WCD® 2000 system via premarket application approval in December 2001 based on clinical data submitted by the manufacturer (4), which has subsequently been published in the peer-reviewed literature. (11)  This prospective nonrandomized trial using historical controls enrolled 289 patients in one of two categories:

1. Patients who used the WCD as a "bridge" to cardiac transplantation, a circulatory-assist device, or a permanent AICD; and
2. Patients who were post-myocardial infarction (MI) and/or post-coronary artery bypass graft (CABG) surgery and temporarily at high risk for ventricular arrhythmias (due to documented VT or VF during the acute event or due to class III or IV congestive heart failure post-event). These patients wore the WCD for up to 4 months or until implantation of a permanent AICD.

During 901 patient-months of device use, there were 8 episodes of VT/VF detected, with 6 of these successfully treated with countershock. There were 6 unnecessary shocks delivered by the device during this period, for a rate of 0.67% per patient-month (95%CI:0.30-1.35). Using historical controls consisting of patients suffering SCA who called emergency services/911, a "control" rate of 25% success for surviving SCA was obtained. Assuming that the device detected all episodes of VF/VT, the FDA review determined that the device had greater efficacy than the "control" group with 90% confidence.

FDA-labeled indications for the device are adult patients who are at risk for sudden cardiac arrest and either are not candidates for or refuse an implantable defibrillator. However, contraindications to an AICD are few. According to the American Heart Association/American College of Cardiology (AHA/ACC) guidelines on AICD use, the device is contraindicated in patients with terminal illness, with drug-refractory Class IV CHF who are not candidates for transplantation, and in patients with a history of psychiatric disorders that interfere with the necessary care and follow-up post-implantation. (2) It is not known how many patients refuse an AICD after it has been recommended for them.

The WCD avoids potential complications associated with AICD implantation, but complication rates with current techniques are low. In one large trial of AICD versus antiarrhythmic drug therapy (5), complications of AICD implantation in 507 patients included hematomas in 13 (2.6%), bleeding requiring transfusion or reoperation in 6 (1.2%), infection in 10 (2.0%), pneumothorax in 8 (1.6%), and cardiac perforation in 1 (0.2%). Early mortality (within 30 days of the procedure) was not higher for the AICD group (2.4%) as compared to the medication group (3.5%).

The above data establish that the WCD device can detect lethal arrhythmias and can successfully deliver a counter shock in the majority of cases. However, these data do not determine the true efficacy of the device or compare the efficacy to alternative treatment(s). For nearly all patients, the alternative is an AICD, which is currently the “gold-standard” treatment for preventing sudden death. Since complications of AICD placement are low and contraindications few, it is unlikely that the WCD can improve outcomes, even in patient populations for whom the need for an AICD is temporary.

Wearable Cardioverter Defibrillator as an Interim to AICD Placement

A small number of patients who meet criteria for and will benefit from an AICD have infectious processes that are contraindications for implantable devices.(1)  This can either be an infectious process that precludes insertion or can occur when an AICD is removed due to infection and there must be a delay before reinsertion.  In these patients, the WCD is considered medically necessary as an interim treatment. There also are small numbers of patients who meet criteria for AICD placement but who are waiting (and meet criteria for) cardiac transplants and have contraindications for AICD placement.  The contraindications may be due to acute unstable medical problems or to concerns about inserting an AICD in a patient when transplant is imminent. The evidence shows:

1. These patients benefit from the cardioverter-defibrillator
2. The WCD can detect and treat lethal dysrhythmias in these patients

Thus, for these patients the WCD improves outcomes compared to use of no device.  The choice of WCD as interim treatment of AICD is made by weighing the relative benefits and risks of the alternative treatment for individual patients.

An updated search of the MEDLINE database through February 25, 2008 identified no new studies which alter the conclusions reached above.

Automatic External Defibrillators

As with WCDs, the appropriate end-point for studies of AEDs for home use is total mortality. There are few peer-reviewed published studies that report on clinical outcomes of AEDs used in the home setting by lay persons, and no studies that evaluate the efficacy of AEDs in reducing mortality compared to alternatives, e.g., AICDs or emergency treatment by first responders. A search of the MEDLINE database through February 25, 2008 identified only one clinical study in which AEDs were used in the home by trained lay persons. (6) Eisenberg and colleagues studied 97 survivors of out-of-hospital VF; 59 patients received home AEDs, and 38 patients served as a control group. After 57 months, there were 14 out-of-hospital cardiac arrests, 10 in the AED group for which the device was available and 4 in the control group. In the AED group, the device was used in 6 of the 10 occurrences; only 2 of these demonstrated VF. One patient was resuscitated and survived with neurological deficits for several months. There was 1 long-term survivor in the control group. It should be noted that this study was published in 1989, prior to FDA approval of implantable cardioverter defibrillators, which would likely have been appropriate for the patients included in this study. Given improved technology and the small numbers of patients included in this study, it is not possible to draw conclusions from this study concerning the impact of home AEDs on mortality in comparison to current treatments.

There has been particular interest in home AED use in children; however, no published clinical trials were identified in which AEDs were studied in a pediatric population. The same discussion that applies to the home use of AEDs for adults also applies to children with some additional concerns. The use of AEDs in children has traditionally not been recommended for the following reasons:

• the prevalence of ventricular dysrhythmia in pediatric cardiac arrest victims is only 10% to 25%;
• algorithms for electronically identifying ventricular dysrhythmia in children
• requiring defibrillation were not established; and
• it was unknown whether, or what amount of biphasic waveform energy (BTE) used by AEDs is safe and/or effective for children under 8 years old or weighing less than 55 lbs.

In 2001, the FDA approved the first automatic external defibrillator system for use on infants and young children who experience cardiac arrest. (7) AEDs marketed up to 2001 were restricted to use on adults and children over eight years of age. The new device, made by Agilent Technologies, Inc., of Palo Alto, CA, is approved for use on infants and children up to age eight and/or weighing up to 55 lbs. Although a universal algorithm to determine the amount of electric current delivered to the patient was used in the design of the pediatric defibrillator (8), the device was not tested in children prior to its clearance for marketing. Therefore, a condition of approval for the device was to require a follow-up study of up to 50 children worldwide to evaluate how well the device performed in actual use. Results of this study have not been published.

In 2003, an advisory statement on the use of AEDs for children was published by the Pediatric Advanced Life Support Task Force, International Liaison Committee on Resuscitation. (9) Although AED use is now recommended in children aged 1-8 who have no signs of circulation, the Task Force did not address whether or when AEDs should be placed in the home setting.

In 2004, the FDA granted marketing clearance for the over-the-counter sale of the HeartStart Home Defibrillator, which was previously available for home use with a prescription. (10) The FDA based its decision on a review of data submitted by the manufacturer that demonstrated the AED could be used by lay people without medical supervision. Mortality data was not collected.

In 2005, the Canadian Coordinating Office for Health Technology Assessment published an assessment of AEDs in the home setting, including the HeartStart Home Defibrillator, and concluded, “No prospective studies demonstrate that the use of AEDs in the home by untrained persons improves health outcomes.  Further investigation is needed to determine the benefit and harm of AEDs in the home.” (12)

An updated search of the MEDLINE database through February 25, 2008 found no additional studies that would alter the above conclusions concerning the use of AEDs in the home.

References

1. BlueCross BlueShield Association Medical Policy Reference Manual, Policy No. 2.02.15
2. Gregoratos G, Cheitlin MD, Conill A et al. ACC/AHA guidelines for implantation of cardiac pacemakers and arrhythmia devices: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Pacemaker Implantation. J Am Coll Cardiol 1998;31(5):1175-209
3. Auricchio A, Klein H, Geller CJ et al. Clinical efficacy of the wearable cardioverter-defibrillator in acutely terminating episodes of ventricular fibrillation. Am J Cardiol 1998;81(10):1253-6
4. FDA document. Summary of Safety and Effectiveness Data, P010030, Lifecor, Inc, WCD® 2000 System. FDA Web site: www.fda.gov/cdrh/pdf/P010030.html (Verified 2/25/08)
5. AVID Investigators. A comparison of antiarrhythmic-drug therapy with implantable defibrillators in patients resuscitated from near-fatal ventricular arrhythmias. The Antiarrhythmics versus Implantable Defibrillators (AVID) Investigators. N Engl J Med 1997;337(22):1576-83
6. Eisenberg MS, Moore J, Cummins RO, et al. Use of the automatic external defibrillator in homes of survivors of out-of-hospital ventricular fibrillation. Am J Cardiol 1989;63(7):443-6
7. FDA document. 510(k) Premarket Notification Summary, K003819, Agilent Technologies, Heartstream FR2 AEDs with Attenuated Defibrillation Pads, M3870A.  FDA Web site: www.fda.gov/cdrh/pdf/k003819.pdf (Verified 2/25/08)
8. Cecchin F, Jorgenson DB, Berul CI, et al. Is arrhythmia detection by automatic external defibrillator accurate for children?: sensitivity and specificity of an automatic external defibrillator algorithm in 696 pediatric arrhythmias. Circulation 2001;103(20):2483-8
9. Samson RA, Berg RA, Bingham R, et al.; Pediatric Advanced Life Support Task Force; International Liaison Committee on Resuscitation. Use of automated external defibrillators for children: an update: an advisory statement from the pediatric advanced life support task force, International Liaison Committee on Resuscitation. Circulation 2003;107(25):3250-5
10. FDA Document. 510(k) Premarket Notification Summary, K040904, Philips Medical System, Philips HeartStart Home Defibrillator. FDA Web site: www.fda.gov/cdrh/pdf4/k040904.pdf  (Verified 02/25/08)
11. Feldman AM, Klein H, Tchou P et al.  Use of a wearable defibrillator in terminating tachyarrhythmias in patients at high risk for sudden death: results of the WEARIT/BIROAD.  Pacing Clin Electrophysiol  2004;27(1):4-9
12. Murray CL, Steffensen I.  Automated external defibrillators for home use.  Issues Emerg Health Technol  2005;Jun (69):1-4

Cross References

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