Surgery Section - Ventricular Assist Devices and Total Artificial Hearts

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

Ventricular assist devices represent a method of providing temporary mechanical circulatory support for those patients not expected to survive until a heart becomes available for their transplant. The scarcity of donor organs has led to the development of interim interventions, such as mechanical assist devices.

A variety of devices have received approval from the U.S. Food and Drug Administration (FDA), encompassing both biventricular and left ventricular devices, as well as devices that are intended to be used in the hospital setting alone and those that can be used as an outpatient. Devices that can be used in an outpatient setting while the patient awaits a human donor heart include the HeartMate Vented Electric Left Ventricular Assist System® and the Novacor LVAS®. In these two systems, the device is surgically placed entirely within the thoracic and abdominal cavity and connected to the power source by a percutaneous drive line.

Left ventricular assist devices (LVAD) are most commonly used as a bridge to transplantation. More recently, given the success of LVADs for prolonged periods of time, there has been interest in using LVADs as permanent "destination" therapy for patients with end-stage heart disease who are not candidates for human heart transplantation due to age or other comorbidities. In November of 2002, the HeartMate device received FDA approval as destination therapy. World Heart Corp., makers of NovaCor® LVAS, announced in 2003 that it is engaged in clinical trials of NovaCor® VAS as destination therapy.

To date, only pulsatile LVAS devices are FDA approved for long-term use. Non-pulsatile axial flow devices are smaller in size and have other technical advantages over pulsatile models. The Jarvik 2000, a non-pulsatile axial flow blood pump, is in phase I clinical trials. In April 2000, the FDA granted the Texas Heart Institute at St. Luke's Episcopal Hospital in Houston, Texas an investigational device exemption to conduct clinical trials of the Jarvik 2000 in 25 patients as part of phase I clinical trials. The study was expanded to include the Cleveland Clinic. Between March 2000 and February 2002, 20 patients received the device.

Devices have also been designed specifically for short-term use, typically in the post-cardiotomy setting for patients who are unable to be weaned off cardiopulmonary bypass or for "high-risk angioplasty." The Thoratec VAD System® is paracorporeal in that the pump is external and is connected by cannulas to the heart and great vessels. The TandemHeart (CardiacAssist) is another device specifically designed for short-term stabilization of patients in the postoperative setting. This device, which had its three components cleared for marketing through the FDA 510(k) process, is unique in that it allows for percutaneous access through the femoral vein, permitting rapid deployment. In addition, it is the first ventricular assist device that uses continuous axial flow, as opposed to pulsatile flow.

Total artificial hearts, in which the recipient undergoes cardiectomy, represent a natural extension of ventricular assist devices as destination therapy.  In 2004, the CardioWest Total Artificial Heart received FDA approval as a bridge to transplantation.   This device is unique in that a pulsatile biventricular device is placed after the native ventricles are excised.  The labeled indication states that this device should only be used in the inpatient setting.  On September 5, 2006 the first totally implanted artificial heart for patients with advanced heart failure involving both pumping chambers was approved under the Humanitarian Use Device (HUD) provisions of the FDA .  The AbioCor Implantable Replacement Heart, manufactured by Abiomed, Inc. (Danvers, Mass.), is intended for people who are not eligible for a heart transplant and who are unlikely to live more than a month without intervention.  The AbioCor system consists of a two-pound mechanical heart that takes over the pumping function of the diseased heart, which is removed during the implantation procedure; a power transfer coil that powers the system across the skin and recharges the internal battery from the outside; and a controller with an internal battery, which are implanted in the patient’s abdomen.  The controller monitors and controls the functioning of the device, including the pumping rate of the mechanical heart.  The internal battery allows the recipient to be free from all external connections for up to one hour.  The system also includes two external batteries that allow free movement for up to two hours.  During sleep and while batteries are being recharged, the system can be plugged into an electrical outlet.  In order to receive the artificial heart, in addition to meeting other criteria, patients must undergo a screening process to determine if their chest volume is large enough to hold the device.  The current, approved device is too large for about 90% of women and for many men.  Abiomed, Inc. has indicated that initially it would provide the artificial heart at five centers around the country and eventually expand to ten centers equipped to use the device.

Policy/Criteria

Ventricular Assist Devices

Ventricular assist devices may be considered medically necessary for any of the following indications (1-3):

1. As a bridge to transplantation for patients who are currently listed as heart transplantation candidates.
2. For short-term use in the post-cardiotomy setting in patients who are unable to be weaned off cardiopulmonary bypass.
3. As destination therapy in patients meeting all of the following criteria:
   1. End-stage heart failure;
   2. Documented ineligibility for human heart transplantation;
   3. Peak oxygen consumption less than or equal to 14ml/kg; and
   4. One of the following criteria is met:

   1)  NYHA class III or IV* for at least 28 days who have received at least 14 days support with an intraaortic balloon pump or are dependent on IV inotropic agents, with two failed weaning attempts, or

   2)  New York Heart Association (NYHA) class IV* heart failure for at least 60 days

   *NYHA Class III = marked limitation of physical activity; less than ordinary activity leads to symptoms

   NYHA Class IV = inability to carry on any activity without symptoms; symptoms may be present at rest

Use of a non-FDA approved ventricular assist device is considered investigational.

Total Artificial Hearts

1. Total artificial hearts may be considered medically necessary as a bridge to heart transplantation for patients with biventricular failure who are currently listed as heart transplantation candidates and who are not considered candidates for a left ventricular assist device.
2. Total artificial hearts are considered investigational in patients who are currently not listed as candidates for heart transplantation.
3. Use of a non-FDA approved total artificial heart is considered investigational.

Scientific Background

Bridge to Transplant LVADs

The above policy is based on a 1996 BlueCross BlueShield Association Technology Evaluation Center (TEC) assessment (2), which concluded that left ventricular assist devices can provide an effective bridge to transplantation. The TEC assessment concluded that patients receiving a VAD showed both higher survival rates to transplantation and higher one-year post-transplant survival compared to patients who did not receive the device. In addition, overall function as reflected by NYHA classification was improved drastically during the period of LVAD support. Although certain adverse effects were more frequent among LVAD recipients (e.g., thromboembolism, infections), the superior survival to transplant, post-transplant survival and NYHA status suggest that overall, patients who receive LVADs have better health outcomes than patients who do not receive them.

Goldstein and colleagues have published a more recent review, confirming the above analysis. (3) It should be recognized that left ventricular assist devices cannot change the number of patients undergoing heart transplantation due to the fixed number of donor hearts. However, the VAD will categorize its recipient as a high priority heart transplant candidate.

An updated literature search of the MEDLINE database through February 14, 2004 did not identify any articles that alter the above conclusions regarding VAD use as a bridge to transplantation. Published studies continue to report that the use of a VAD does not compromise the success of a subsequent heart transplant. In fact, it may improve post-transplant survival, thus improving the utilization of donor hearts. (4-7) Currently available VADs consist of pulsatile devices that require both stiff power vent lines that perforate the skin and bulky implantable pump chambers. There is considerable research interest in developing non-pulsatile axial flow systems that have the potential for small size and low-noise levels. (8-13)

Bridge to Recovery (Post Cardiotomy) VADs

VAD support was originally indicated for the treatment of postcardiotomy cardiogenic shock in patients who could not be weaned from cardiopulmonary bypass. VAD use in this setting is temporary and brief, lasting between 1.4 and 5.7 days. The overall salvage rate for this indication is low, at approximately 25 percent; however, without VAD support, patients with refractory postcardiotomy cardiogenic shock would experience 100 percent mortality. (14)

LVADs as Destination Therapy

The policy statement regarding LVADs as destination therapy is based on a 2002 TEC assessment (15) that offered the following observations and conclusions:

• The available evidence comes from a single, well-designed and rigorously conducted randomized trial, known as the REMATCH study. (16) The study was a cooperative effort of Thoratec, Columbia University and the National Institutes of Health.
• The randomized trial found that patients with end-stage heart failure who are not candidates for cardiac transplantation have significantly better survival on an LVAD compared with treatment by optimal medical therapy. Median survival was improved by approximately 8.5 months. Serious adverse events were more common in the LVAD group, but these appear to be outweighed by this group's better outcomes on function. NYHA Class was significantly improved, as was quality of life among those living to 12 months.
• LVAD patients spend a greater relative proportion of time inside the hospital than medical management patients do, but the survival advantage would mean a longer absolute time outside the hospital.

An updated search of the MEDLINE database through February 14, 2004 identified no new studies which alter the conclusions reached above.

Total Artificial Hearts

In 2004, the CardioWest Total Artificial heart received FDA approval for use as a bridge to transplant. The approval was based on the results of a nonrandomized, prospective study of 81 patients. (17) Patients had failed inotropic therapy and had biventricular failure and thus were not considered appropriate candidates for an LVAD. The rate of survival to transplant was 79%, which was considered comparable to the experience with LVAD in patients with left ventricular failure. The mean time from entry into the study until transplantation or death was 79.1 days.

Like the Cardiowest, the AbioCor is a pulsatile device, but instead of pneumatic drives, the AbioCor uses an electro hydraulic actuator system.  The current AbioCor device weighs approximately two pounds.  In currently available studies, the AbioCor has only been used as destination therapy for end-stage patients with congestive heart failure.  As of May 2003, implants have been performed in only 11 patients enrolled in the AbioCor clinical trial.  Dowling and colleagues reported on the first seven patients. (18) The 30-day survival rate was 71% compared with the predicted survival rate of 13% with only medical therapy.  At 60 days, 43% were still alive and as of July 2006 two patients were still alive, 234 and 181 days postoperatively and remain hospitalized.  Deaths were due to intraoperative bleeding at the time of implantation, cerebrovascular accidents, pulmonary embolism, and multiorgan failure.  No reports of serious device malfunction have been reported for the seven patients.  Frazier and colleagues reported information on four additional patients receiving the AbioCor.  Using the same inclusion criteria the device supported three patients for greater than 100 days, whereas a fourth patient expired at 53 days.  There were no device related problems reported.  Abiomed’s initial request in 2005 for humanitarian device exemption (HDE) status was denied.  The Circulatory System Devices Panel noted significant concerns regarding anticoagulation and quality of life.  However, in September 2006 Abiomed’s request for HDE status of the AbioCor was approved for use in patients who are not candidates for heart transplant. (20)

October 2007 Update

An updated search of the literature through September 2007 for clinical trial evidence on VADs and total artificial hearts did not return any information that would alter the conclusions of the policy criteria as written.  Therefore the policy is unchanged at this time.

References

1. BlueCross BlueShield Association Medical Policy Reference Manual, Policy No. 7.03.11
2. 1996 TEC Assessment: Ventricular Assist Devices in Bridging to Heart Transplantation
3. Goldstein DJ, Oz MC, Rose EA. Implantable left ventricular assist devices. N Engl J Med 1998;339(21):1522-33
4. Aaronson KD, Eppinger MJ, Dyke DB et al. Left ventricular assist device therapy improves utilization of donor hearts. J Am Coll Cardiol 2002;39(8):1247-54
5. Frazier OH, Rose EA, McCarthy P et al. Improved mortality and rehabilitation of transplant candidates treated with long-term implantable left ventricular assist system. Ann Surg 1995;222(3):327-38
6. Bank AJ, Mir SH, Nguyen DQ et al. Effects of left ventricular assist devices on outcomes in patients undergoing heart transplantation. Ann Thorc Surg 2000;69(5):1369-75
7. Jaski BE, Kim JC, Naftel DC et al. Cardiac transplant outcome of patients supported on left ventricular assist device versus intravenous inotropic therapy. J Heart Lung Transplant 2001;20(4):449-56
8. Wieselthaler GM, Schima H, Lassnigg AM et al. Lessons learned from the first clinical implants of the DeBakey ventricular assist device axial pump: a single center report. Ann Thorac Surg 2001;71(3 Suppl):S139-46
9. Goldstein DJ. Worldwide experience with the MicroMed DeBakey Ventricular Assist Device as a bridge to transplantation. Circulation 2003;108 Suppl 1: II272-7
10. Salzberg S, Lachat M, Zund G, et al. Left ventricular assist device as bridge to heart transplantation--lessons learned with the MicroMed DeBakey axial blood flow pump. Eur J Cardiothorac Surg 2003;24(1):113-8
11. Vitali E, Lanfranconi M, Ribera E, et al. Successful experience in bridging patients to heart transplantation with the MicroMed DeBakey ventricular assist device. Ann Thorac Surg 2003;75(4):1200-4
12. Grinda JM, Latremouille CH, Chevalier P, et al. Bridge to transplantation with the DeBakey VAD axial pump: a single center report. Eur J Cardiothorac Surg 2002;22(6):965-70
13. Frazier OH, Myers TJ, Westaby S, Gregoric ID. Use of the Jarvik 2000 left ventricular assist system as a bridge to heart transplantation or as destination therapy for patients with chronic heart failure. Ann Surg 2003;237(5):631-6
14. Braunwald E, Zipes DP, Libby P, eds. Braunwald: Heart Disease: A Textbook of Cardiovascular Medicine, 6th ed. Philadelphia: W.B. Saunders Company, 2001
15. 2002 TEC Assessment: Left Ventricular assist devices as destination therapy for end-stage heart failure
16. Rose EA, Gelijns AC, Moskowitz AJ et al. Long term mechanical left ventricular assistance for end-stage heart failure. N Engl J Med 2001;345:1435-43
17. Copeland JG, Smith RG, Arabia FA et al. Cardiac replacement with a total artificial heart as a bridge to transplantation. N Eng J Med 2004;351(9):859-67
18. Dowling RD, Gray Jr LA, Etoch SW et al. Initial experience with the AbioCor implantable replacement heart system. J Thoracic Cardiovasc Surg 2004; 127:131-41
19. Frazier OH, Dowling RD, Gray Jr LA et al. The total artificial heart: where we stand. Cardiology 2004; 101:117-21
20. FDA approval letter: www.fda.gov/cdrh/mda/docs/h040006.html  (Verified 9/17/07)

Cross References

Heart Transplant, Regence Medical Policy Manual, Transplant Policy No. 2

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