Heart Transplantation

Introduction:
A heart transplant is an operation in which a failing, diseased heart is replaced with a healthier, donor heart. Heart transplant is a treatment that’s usually reserved for people who have tried medications or other surgeries, but their conditions haven’t improved sufficiently.

While a heart transplant is a major operation, medical technology has improved greatly since the first heart transplant in 1967, and your chance of survival is higher than ever.

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(Diagram illustrating the placement of a donor heart in an orthotopic procedure. Notice how the back of the patient’s left atrium and great vessels are left in place).

When faced with a decision about having a heart transplant, know what to expect of the heart transplant process, the surgery itself, potential risks and follow-up care.

The most common procedure is to take a working heart from a recently deceased organ donor (allograft) and implant it into the patient. The patient’s own heart may either be removed (orthotopic procedure) or, less commonly, left in to support the donor heart (heterotopic procedure). It is also possible to take a heart from another species (xenograft), or implant a man-made artificial one, although the outcome of these two procedures has been less successful in comparison to the far more commonly performed allografts.

Cardiac transplantation is a widely accepted therapy for the treatment of end-stage congestive heart failure. Most candidates for cardiac transplantation have not been helped by conventional medical therapy and are excluded from other surgical options because of the poor condition of the heart. About 45% of the candidates have ischemic cardiomyopathy; however, this percentage is rising because of the increase in coronary artery disease in younger age groups. Of the candidates, 54% have some form of dilated cardiomyopathy, which often has an unclear origin. The remaining 1% of candidates fall into the category of other diseases, including congenital heart disease, that are not amenable to surgical correction.

Candidacy determination and evaluation are key components of the process, as is postoperative follow-up care and immunosuppression management. Proper execution of these steps can culminate in an extremely satisfying outcome for both the physician and patient.

Why it’s done:-
Heart transplants are performed when other treatments for heart problems haven’t worked, leading to heart failure. In adults, heart failure can be caused by:

*Coronary artery disease
*Cardiomyopathy
*Valvular heart disease
*Congenital heart defect — a heart problem you’re born with
*Failure of a previous heart transplant

In children, heart failure is most often caused by a congenital heart defect.

A heart transplant isn’t the right treatment for everyone, however. Certain factors may mean you’re not a good candidate for a heart transplant. While each case is considered individually by a transplant center, factors that could prevent you from having a heart transplant include:

*Being age 65 or older
*Having another medical condition that could shorten life, regardless of receiving a donor heart
*Poor blood circulation
*Personal medical history of cancer
*Being unwilling or unable to make lifestyle changes necessary to keep your donor heart healthy

Specific indications:-

*Dilated cardiomyopathy
*Ischemic cardiomyopathy
*Congenital heart disease for which no conventional therapy exists or that conventional therapy has failed
*Ejection fraction less than 25%
*Intractable angina or malignant cardiac arrhythmias for which conventional therapy has been exhausted
*Pulmonary vascular resistance of less than 2 Wood units
*Age younger than 65 years

Ability to comply with medical follow-up care.

History
The first heart transplanted into a human occurred in 1964 at the University of Mississippi Medical Center in Jackson, Mississippi when a team led by Dr. James Hardy transplanted a chimpanzee heart into a dying patient. The heart beat for 70 minutes before stopping. Dr. Hardy had performed the first human lung transplant the previous year. [1] The first human to human heart transplant was performed by cardiac surgeon Christiaan Barnard at Groote Schuur Hospital in December 1967. The patient was Louis Washkansky of Cape Town, South Africa, who lived for 18 days after the procedure before dying of pneumonia. The donor was Denise Darvall, who was rendered brain dead in a car accident.

The first successful United States heart transplant was done at Stanford University by doctor Norman Shumway in January, 1968. Subsequently, another transplant was done at St. Lukes hospital in Houston Texas by Denton Cooley in June 1968. The donor was a teenage suicide victim (who had had an aortic coarctation repaired as a young child, also by Dr. Cooley) and the recipient, Mr. Thomas, had terminal severe cardiomyopathy. He survived 8 months before dying of rejection of the transplanted heart. A series of five subsequent heart transplants were done that month by Dr. Cooley followed by a number of transplants in Houston that year before the program was canceled, leaving only Norman Shumway at Stanford University doing heart transplants and research on the rejection phenomenon.

On 27 April 1968, French surgeon Christian Cabrol performed the first European heart transplantation in the Paris Pitié-Salpêtrière Hospital. The patient was a 66 year old man, Clovis Roblain, who survived 53 hours before dying of a pulmonary embolism.

In 1984, at two years old, Elizabeth Craze became the youngest surviving heart transplant patient.

The concept of heart transplantation dates back to at least 400 AD in China. The book of Liezi tells a story of Bian Que exchanging the hearts of two warriors to balance their personal characteristics.

Risk Factors:

Although receiving a donor heart can save your life, having a heart transplant has many risks. The most significant risk is your body rejecting the donor heart.

Rejection of the donor heart
Your immune system may see your donor heart as a foreign object that’s not supposed to be in your body. If this happens, your immune system will try to attack your donor heart. Although all people who receive a heart transplant receive immunosuppressants — medications that suppress the activity of your immune system — nearly 25 percent of heart transplant recipients still have some signs of rejection during the first year after transplantation.

To determine whether your body is rejecting the new heart, you’ll have frequent biopsy tests for several months after your transplant. During the biopsy, a tube is inserted into a vein in your neck or groin and directed to your heart. A biopsy device is run through the tube to extract a tiny sample of heart tissue, which is examined in a lab. Because rejection is most likely to occur in the early weeks and months after heart transplantation, the frequency of heart biopsies is greatest during this early period. It’s possible you’d have signs or symptoms that your body is rejecting your donor heart. These signs and symptoms could include:

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*Shortness of breath
*Fever
*Weight gain due to water retention
*Not urinating as much as usual
*Fatigue

Additional risks :-
Other risks following your heart transplant include:

*Problems with your arteries. After your transplant, it’s possible the walls of the arteries in your heart could thicken and harden, leading to cardiac allograft vasculopathy (CAV). This can make blood circulation through your heart difficult and can cause a heart attack, heart failure, heart arrhythmias or sudden cardiac death.

*Medication side effects. The immunosuppressants you’ll need to take for the rest of your life can cause serious kidney damage and other problems.

*Cancer. Immunosuppressants can also increase your cancer risk. Taking these medications can put you at a greater risk of skin and lip tumors and non-Hodgkin’s lymphoma, among others.

*Infection. Immunosuppressants decrease your body’s ability to fight infection. Many people who have heart transplants have an infection that requires them to be admitted to the hospital the first year after their transplant.

Procedures:-

Pre-operative
A typical heart transplantation begins with a suitable donor heart being located from a recently deceased or brain dead donor. The transplant patient is contacted by a nurse coordinator and instructed to attend the hospital in order to be evaluated for the operation and given pre-surgical medication. At the same time, the heart is removed from the donor and inspected by a team of surgeons to see if it is in a suitable condition to be transplanted. Occasionally it will be deemed unsuitable. This can often be a very distressing experience for an already emotionally unstable patient, and they will usually require emotional support before being sent home. The patient must also undergo many emotional, psychological, and physical tests to make sure that they are in good mental health and will make good use of their new heart. The patient is also given immunosuppressant medication so that their immune system will not reject the new heart.

Operative
Once the donor heart has passed its inspection, the patient is taken into the operating room and given a general anesthetic. Either an orthotopic or a heterotopic procedure is followed, depending on the condition of the patient and the donor heart.

Orthotopic procedure
The orthotopic procedure begins with the surgeons performing a median sternotomy to expose the mediastinum. The pericardium is opened, the great vessels are dissected and the patient is attached to cardiopulmonary bypass. The failing heart is removed by transecting the great vessels and a portion of the left atrium. The pulmonary veins are not transected; rather a circular portion of the left atrium containing the pulmonary veins is left in place. The donor heart is trimmed to fit onto the patients remaining left atrium and the great vessels are sutured in place. The new heart is restarted, the patient is weaned from cardiopulmonary bypass and the chest cavity is closed.

Heterotopic procedure
In the heterotopic procedure, the patient’s own heart is not removed before implanting the donor heart. The new heart is positioned so that the chambers and blood vessels of both hearts can be connected to form what is effectively a ‘double heart’. The procedure can give the patients original heart a chance to recover, and if the donor’s heart happens to fail (eg. through rejection), it may be removed, allowing the patients original heart to start working again. Heterotopic procedures are only used in cases where the donor heart is not strong enough to function by itself (due to either the patients body being considerably larger than the donor’s, the donor having a weak heart, or the patient suffering from pulmonary hypertension).

Post-operative
The patient is taken into ICU to recover. When they wake up, they will be transferred to a special recovery unit in order to be rehabilitated. How long they remain in hospital post-transplant depends on the patient’s general health, how well the new heart is working, and their ability to look after their new heart. Doctors typically like the new recipients to leave hospitals soon after surgery because of the risk of infection in a hospital (typically 1 – 2 weeks without any complications). Once the patient is released, they will have to return to the hospital for regular check-ups and rehabilitation sessions. They may also require emotional support. The number of visits to the hospital will decrease over time, as the patient adjusts to their transplant. The patient will have to remain on lifetime immunosuppressant medication to avoid the possibility of rejection. Since the vagus nerve is severed during the operation, the new heart will beat at around 100 bpm until nerve regrowth occurs.

Living organ’ transplant
Doctors made medical history in February 2006, at Bad Oeynhausen Clinic for Thorax- and Cardiovascular Surgery, Germany, when they successfully transplanted a ‘beating heart’ into a patient.Normally a donor’s heart is injected with potassium chloride in order to stop it beating, before being removed from the donor’s body and packed in ice in order to preserve it. The ice can usually keep the heart fresh for a maximum of four to six hours with proper preservation, depending on its starting condition. Rather than cooling the heart, this new procedure involves keeping it at body temperature and hooking it up to a special machine called an Organ Care System that allows it to continue beating with warm, oxygenated blood flowing through it. This can maintain the heart in a suitable condition for much longer than the traditional method.

Prognosis:-

The prognosis for heart transplant patients following the orthotopic procedure has greatly increased over the past 20 years, and as of 11 August 2006, the survival rates were as follows.[8]

*1 year: 86.1% (males), 83.9% (females)
*3 years: 78.3% (males), 74.9% (females)
*5 years: 71.2% (males), 66.9% (females)

In a November 2008 study conducted on behalf of the U.S. federal government by Dr. Eric Weiss of the Johns Hopkins University School of Medicine, it was discovered that heart transplants- all other factors being accounted for- work better in same-sex transplants (male to male, female to female). However, due to the present acute shortage in donor hearts, this may not always be feasible.

As of the end of 2007, Tony Huesman is the world’s longest living heart transplant patient, having survived for 29 years with a transplanted heart. Huesman received a heart in 1978 at the age of 20 after viral pneumonia severely weakened his heart. The operation was performed at Stanford University under American heart transplant pioneer Dr. Norman Shumway, who continued to perform the operation in the U.S. after others abandoned it due to poor results.. Another noted heart transplant recipient, Kelly Perkins, climbs mountains around the world to promote positive awareness of organ donation. Perkins is the first heart transplant recipient to climb to the peaks of Mt. Fuji, Mt. Kilimanjaro, the Matterhorn, Mt. Whitney, and Cajon de Arenales in Argentina in 2007, 12 years after her transplant surgery. Dwight Kroening is yet another noted recipient promoting positive awareness for organ donation. Twenty two years after his heart transplant, he is the first to finish an Ironman competition.  Fiona Coote was the second Australian to receive a heart transplant in 1984 (at age 14) and the youngest Australian. At 24 years since her transplant she is also a long term survivor and is involved in publicity and charity work for the red cross, and promoting organ donation in Australia.

The record for heart transplant longevity in a senior recipient may go to Edward Daunheimer of Newburyport, Massachusetts, who received his heart on 19 February 1997 at the Tufts New England Medical Center at the age of 65 (the upper age limit for heart transplants). Mr. Daunheimer has so far lived a healthy life for 12 years with his new heart, defying statistical probabilities by a large margin.

Expected results:-
Most people who receive a heart transplant enjoy a high quality of life. They can return to work within three to six months of a heart transplant and have few activity restrictions.

Recipient survival rates vary based on a number of factors, but overall the survival rate is nearly 90 percent after one year and 72 percent after five years.

What if your new heart fails?
Heart transplants aren’t successful for everyone. Your new heart may fail because of organ rejection or because of the development of valvular heart disease or coronary artery disease. Should this happen, your doctor may recommend adjusting your medications or in more extreme cases, another heart transplant.

In some cases, additional treatment options are limited and you may choose to discontinue treatment. Discussions with your heart transplant team, physician and family should address your expectations and preferences for treatment, emergency care and end-of-life care.

Resources:-
http://emedicine.medscape.com/article/429816-overview
http://en.wikipedia.org/wiki/Heart_transplantation
http://www.mayoclinic.com/health/heart-transplant/

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