Destination therapy is a therapy that is final rather than being a transitional stage until another therapy—thus, in transportation metaphor, a destination in itself rather than merely a bridge or road to the destination. The term usually refers to ventricular assist devices or mechanical circulatory support to keep the existing heart going, not just until a heart transplant can occur, but for the rest of the patient's life expectancy. It is thus a course of treatment for severe (e.g.,

NYHA The New York Heart Association (NYHA) Functional Classification provides a simple way of classifying the extent of heart failure. It places patients in one of four categories based on how much they are limited during physical activity; the limitati ...

class IV/ACC stage D)

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, a ...

patients who are not likely candidates for transplant. In contrast, bridge-to-transplant therapy is a way to stay alive long enough, and stay healthy enough, to await transplant while maintaining eligibility for transplant. Heart failure is a leading cause of death in industrialized economies. Among those with serious heart illness some are, for a variety of possible medical circumstances, ineligible for a heart transplant. Destination therapy provides a possibility to extend their lives and improve their quality of life. In addition, destination therapy may in some cases turn out to remedy the condition that excluded transplantation Estimates place the population in the United States that may benefit from destination therapy at 50,000 – 100,000 patients per year. The addressable population outside of the US is thought be similar in size.

Indications

In order for a patient to be recommended for destination therapy with an LVAD, he/she will have presented with end-stage heart failure, and will be ineligible for a transplant due to age, additional health problems, or other complications. In addition, patients may be eligible but are not suitable for heart transplant because they have other circulatory conditions unrelated to the heart.

History

In 2000, the Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure (REMATCH) trial was conducted. REMATCH was a multi-center study supported by the National Heart, Lung, and Blood Institute to compare long-term implantation of left ventricular assist devices with optimal medical management for patients with end-stage heart failure who require, but do not qualify to receive cardiac transplantation. Based on the results of this study, the U.S. Food and Drug Administration (FDA) granted a Premarket Approval for the Thoratec HeartMate XVE LVAD to be used for destination therapy. In addition, the

Centers for Medicare and Medicaid Services The Centers for Medicare & Medicaid Services (CMS), is a federal agency within the United States Department of Health and Human Services (HHS) that administers the Medicare program and works in partnership with state governments to administer M ...

expanded Medicare coverage to include such therapy.As of September 2009, the Thoratec HeartMate XVE is the only FDA-approved device for use specifically as destination therapy. Other devices are currently under investigation for this indication, including the next generation of the device, HeartMate II, which is expected receive FDA-approval in early 2010.

Procedure

Pre-operative

Most LVADs are implanted in scheduled operations and require careful preparation of the patient for surgery, including an assessment by an anesthesiologist. The cardiologist in the coronary care unit (CCU) usually stabilizes and prepares the patient for surgery. Some patients will have invasive monitoring instituted in the CCU and will be supported with inotropes,

vasopressor An antihypotensive agent, also known as a vasopressor agent or simply vasopressor, or pressor, is any substance, whether endogenous or a medication, that tends to raise low blood pressure. Some antihypotensive drugs act as vasoconstrictors to inc ...

s and

IABP The intra-aortic balloon pump (IABP) is a mechanical device that increases myocardial oxygen perfusion and indirectly increases cardiac output through afterload reduction. It consists of a cylindrical polyurethane balloon that sits in the aorta, ...

. In addition, recent laboratory results and assessment of the patient's physical status are required. Patients are typically cross-matched for four units of blood.

Peri-operative

Ventricular assist devices require open-heart surgery for implantation. An incision is made through the breastbone to expose the heart.

Heparin Heparin, also known as unfractionated heparin (UFH), is a medication and naturally occurring glycosaminoglycan. Since heparins depend on the activity of antithrombin, they are considered anticoagulants. Specifically it is also used in the treatm ...

will be given to keep the patients blood from clotting. The blood is rerouted to a heart-lung machine that will pump and oxygenate blood. A pocket for the LVAD is formed in the abdominal wall. A tube is then used to channel blood from the ventricle to the LVAD. Another tube is used to connect the pump to the aorta. When the pump is adequately supporting the heart, the patient will be removed from the heart-lung machine and the chest will be closed.

Post-operative

During the REMATCH trial, several complications were reported for patients who received the LVAD. They reported post-operative pain after LVAD implantation. During an average 400 days of survival, 30 percent of the devices had an internal failure requiring another operation, and almost every patient who had a re-operation did not survive. Other adverse effects included bleeding, infection and lengthened hospital stays. Quality of Life (QoL) measures found that the LVAD group scored better or equal to the medical-therapy management group.

Prognosis

The REMATCH study randomly assigned 129 patients with Class IV end-stage heart failure who were ineligible for cardiac transplantation. Within the study, 68 patients received an LVAD and 61 patients received optimal medical management. Among the patients who received the LVAD, there was a reduction of 48 percent in the risk of death from any cause, compared with the medical-therapy group. Rates of survival among REMATCH study patients: The frequency of serious adverse events in the LVAD group was 2.35 times that in the medical-therapy group, with a predominance of infection, bleeding and malfunction of the device. However, the quality of life was significantly improved at one year in the LVAD group.

References

{{DEFAULTSORT:Destination Therapy Interventional cardiology