heart transplantation

Heart transplantation

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A heart transplant is a transplant of a complete human heart. Heart failure (or congestive heart failure) is a condition in which the heart cannot pump enough blood to meet other bodily organs’ needs. People with heart failure should not strain because they are short of breath and tired. They can also have life-threatening irregular heart rhythms.

Last year, more than 41,000 Americans died of congestive heart failure, and as many as 4.8 million of them live with it.

Scientists have made progress in identifying diseases that cause heart failure. Medications for the treatment of congestive heart failure are also being worked on.

Still, when the heart is so damaged that it is impossible to repair, current treatment methods are sometimes unable to alleviate symptoms and prolong life. When all hope of improvement is lost, a more drastic approach should be considered – such as a heart transplant.

In heart transplantation, the diseased heart is removed and replaced with a healthy human heart. In special cases, the diseased heart does not have to be removed, but the surgeon can place a healthy heart next to the diseased one (so-called ‘transplant’ heart transplant) to act as a supplementary pump.

Medical science has made great strides over the past 20 years. Once a science sensation and a science fiction dream, heart transplantation have become a reality today. For those who do not respond to other heart disease treatment types, a heart transplant can be a miracle that will save their lives.

Problems in the first years

The first human heart transplant was performed by Dr. Christian Barnard 3. December 1967 in a celebrated operation in Capetown, South Africa.

In the first years, heart transplants were usually not successful because the patient’s body often ‘rejected’ the new heart. This happened because of the human body’s immune system, made up of white blood cells and other cells that recognize ‘foreign’ material and react to it.

Take the example of a person who cuts a finger. If bacteria enter the incision, white blood cells move toward the incision to destroy them before the infection begins. This is a normal defensive response.

A similar response occurs toward a newly donated heart after a transplant. It is exposed to attacks. At the time of the first proceedings, heart transplantation medical science could not interpret how the body’s immune system ‘sees’ the transplanted heart as foreign. Today, survival rates after heart transplants have gradually improved thanks to an understanding of how the immune system works. 

Today’s heart transplant results

heart transplant pulse

Today heart transplantation is performed in more than 2,300 Americans each year at over 150 heart transplant centers. Over two out of five of these patients are expected to survive for a year, and over seven out of ten will be alive three years after surgery.

  • Heart transplants are performed each year in more than 2,300 Americans.
  • The one-year survival rate is 89%
  • The three-year survival rate is 84%

Patients with the longest survival live more than 20 years after transplantation.

Quality of life also improves dramatically after a heart transplant. Many activities – walking, dancing and even running – can return to normal. Rather, heart transplant recipients competed in a marathon, and one person became a professional athlete (in the Grand Futsal League).

Transplant recipients must take lifelong medications (known as immunosuppressive or anti-rejection drugs) to prevent organ transplant rejection and deal with these drugs’ side effects.

The transplanted heart is ‘denervated’ for at least a year after surgery. This means that it is not connected to the rest of the body via the nervous system. The network of fine nerves broken during the old heart’s removal cannot be reconnected surgically. The denervated heart normally works, which does not cause any recipient problems. However, it can cause a faster pulse after transplantation. A normal resting heart regularly beats 60 to 80 times per minute, while a transplanted heart can beat 130 times per minute.

Indications for heart transplantation

Heart transplantation is performed when congestive heart failure or heart injury cannot be treated by any other medical or surgical method. Heart transplantation is reserved for people at high risk of dying from heart disease within one to two years.

Most patients who undergo a transplant have either of two problems. The first is irreversible heart injury due to the arteries’ calcification (coronary heart disease) and multiple heart attacks. Another problem is heart muscle disease (cardiomyopathy). In this condition, the heart cannot contract normally due to damage to the heart muscle cells.

Sometimes heart transplants are performed in people with other forms of heart disease, and these include the following: 1) heart valve abnormalities that cause damage to the heart muscle; 2) abnormalities of the heart muscle or other structures present at birth (congenital heart defects); or 3) rare conditions such as heart tumors.

Until recently, anti-rejection drugs’ side effects prevented heart transplants in very young or older people. That, however, has changed. Now transplantation can be performed in people of all ages, from newborns to those in their seventies.

The chances of successful heart transplantation, in the long run, depend in part on the extent of damage or disease to other organs that cannot be cured. (This may include a fatal stroke, chronic lung, liver, or kidney disease.) In people with these conditions, transplantation would be of little or no benefit. If the pulmonary arteries’ blood pressure rises too much and cannot be lowered, it can prevent a heart transplant. This is because a normal, gifted heart may be unable to cope with the flow of blood through diseased blood vessels. A ‘transplant’ heart transplant can be applied in such a case.

Other medical issues are also considered when deciding whether a person is a good candidate for a heart transplant. These include a proven active infection, diabetes, or blood clots in the lungs.

As recipients must withstand the emotional burden of transplantation and its consequences, a support network among family members and friends plays an important role. The recipient must also be able to deal with potentially serious drug side effects and the need for lifelong treatment and medical care.

Selection and recruitment of providers

It is estimated that 16,000 people in the United States would benefit from a heart transplant each year. However, only about 2,300 surgeries are performed each year because too few hearts are donated.

All in all, it is a matter of public awareness and legislation. Some families of potential donors refuse to give consent to donate organs to their loved ones because they think they will have to pay the cost of organ harvesting. That is not correct!

Hospitals today are required to develop policies and procedures to explain to families organ donation. Legal provisions for this ‘requested application’ have been adopted in 42 states and in the District of Columbia (DC). Likewise, hospitals with Medicare and Medicaid programs must have written provisions in place to identify potential organ donors and report them to the procurement authority (OPO). Since January 1988. all hospitals must have elaborate policies and procedures in place to identify potential donors. Sometimes the hospital is unable to identify a good donor despite the hospital requirements. If the donation is not requested from the family of a potential donor, and the family would like to give someone else a chance at life, they should consult a doctor or nurse.

When a hospital or OPO as a member of the Unified Organ Donation Network ( United Network for Organ Sharing / UNOS / ) identifies the donor, the person in charge of identifying the donor should do two things: determine whether the donated organ is suitable for transplantation and coordinate the distribution of the organ. However, all this depends on the family of the potential donor. If the family does not allow the use of organs, the organs will not be removed.

Most donors donate multiple organs. For example, the heart, liver, kidneys, pancreas, and lungs can be obtained from the same donor.

Donated hearts are given to patients based on the donor’s blood type and body weight, and the blood type, body weight, disease severity, and geographic location of the potential recipient. All this data is stored in the UNOS computer. Preference is given to seriously ill recipients at the nearest transplant center.

A suitable donor is a young to middle-aged person for whom brain death has been reported based on standard criteria whose heart is still working well. All donors are tested for the presence of hepatitis B and C viruses and human immunodeficiency virus (which causes AIDS). Any evidence of these infections means that the person in question is not eligible as an organ donor.

When the transplant team at the recipient’s hospital receives notification of a suitable heart, they travel quickly to the donor’s hospital. There the heart is taken out and placed in a special cold solution to keep it alive (though not beating). The heart can be disconnected from the donor’s bloodstream in about four hours without losing its ability to function normally. Time, then, is crucial. When the heart is removed, the team returns to their hospital and performs surgery.

The process of donating the heart

  • The potential donor signs the organ donor card.
  • After brain death, contact with the donor’s relatives is made.
  • The closest relative gives consent.
  • The acceptability of the heart, lungs, liver, kidneys, cornea, bone, and skin for possible transplantation is determined.
  • Recipients are identified and prioritized via a local program or UNOS computer.
  • The recipient is notified and admitted to the hospital.
  • Surgical teams from the transplant centers arrive at the donor’s hospital at a pre-arranged time.
  • Surgical removal of the donor’s organs begins.
  • The recipient is brought to the operating room, where the removal of the diseased heart is coordinated with the donor organ’s arrival.

Complications

 Heart transplantation is a treatment method for those people whose life expectancy is minimal and in whom there are no other options. It is not a ‘cure’ because a new heart requires lifelong care. Complications can occur after transplantation. Despite the complications, in most people, the quality of life after transplantation is excellent. Those who worked before a heart transplant usually return to work after a short recovery period.

The most common early complications after heart transplantation are organ rejection and infections. Strict precautions are needed to prevent them from occurring.

All adult patients undergo a heart biopsy procedure, taking small heart tissue pieces. The procedure is performed under local anesthesia, after which a long instrument is inserted through a vein. The pieces of tissue are then examined under a microscope. Identifying the white blood cells that cause the immune response is the only available method to diagnose rejection.

In most cases, doctors may detect rejection before the patient begins to feel unwell or some active sign appears that the heart is not working normally. Rejection is treated by increasing the dose of the immunosuppressive agent. Six to eight months after a heart transplant, the body’s effort to reject the donor’s heart decreases. A certain form of ‘submitting’ a new heart develops. Although anti-rejection drugs should be taken continuously and for life, their dose may be reduced after this high-risk early period. This, in turn, will help eliminate the side effects of these drugs.

Two-thirds of deaths in the first year after transplantation occurs in the first three months. The vast majority of them are caused by early rejection or infection.

Drug side effects

Side effects of anti-rejection medications are common. Corticosteroids, especially prednisone, cause many side effects when given high doses early after transplant surgery. Patients may gain weight, retain fluid, or have an unusual distribution of body fat. (Weight increases more in the abdomen and hips than in the arms and legs.) There may be a strangely rounded shape of the face (moon face), weakening of the skin and hair, diabetes (which often needs to be treated), Gallstones, bone weakness, stunted growth (in children), joint damage, and infections. Often these problems are sought to be reduced by interrupting or lowering the steroid dose.

Azathioprine (Imuran) is another drug given to many organ recipients. It can cause abnormalities in kidney or liver function, and lower white blood cell counts. This, in turn, facilitates the development of infection in the recipient concerned.

Cyclosporine is an immunosuppressive agent. He is partly responsible for the dramatic improvement in survival rates in recent years. Cyclosporine causes an increase in blood pressure (hypertension), which needs to be treated in most cases. Abnormalities of renal and hepatic function may also occur, and these side effects may be alleviated by lowering the dose of the drug. Cyclosporine interacts with many other medicines that the person may be taking, so it should be closely monitored for successful use.

Immunosuppressive therapy

Heart transplant patients receiving immunosuppressive therapy have a higher incidence of cancer than the general population.

Infection is also a major problem after transplantation in all people taking anti-rejection drugs. The reason for this is simple. The same white blood cells that attack the transplanted heart are responsible for removing foreign particles (such as bacteria) from the bloodstream. Thus, measures taken to protect against rejection may increase infection risk. This is especially true in the event of rejection when it is necessary to increase the dose of anti-rejection drugs.

After the first year, the main threat to survival comes from blockages in the arteries of the transplanted heart. Clogged heart vessels generally do not cause chest pain because the heart is not connected to the nervous system. Most centers perform cardiac catheterization and angiogram (examination of the heart and blood vessels using dye) at a certain time after transplantation.

This form of vascular disease develops in about 25 percent of heart transplant patients within three years of transplantation. If this blockage continues, abnormalities in the work of the heart muscle or irregular heartbeat can occur so that another transplant may be considered. Intensive medical research is being conducted to determine the causes of this serious complication and find ways to prevent them.

Heart transplantation in the future

Heart transplantation has seen a dramatic improvement over the last 20 years. It has benefited, extended, and enabled many people to live a more active life. With new scientific advances, long-term survival is becoming increasingly likely.

Medical science has made great strides in diagnosing rejection and developing immunosuppressive drugs. Several new anti-rejection drugs are in the early stages of development. Several new rejection prevention options with fewer side effects are expected to be available soon.

New techniques are also being developed to diagnose rejection without a heart biopsy. Researchers are focusing on blockages in the blood vessels that form in the new heart. They work tirelessly to identify the causes of this serious complication and learn how to treat and prevent it most effectively.

Even if these problems are addressed, the current lack of donated organs prevents a new heart transplant from anyone who needs it. Other methods will be needed. Artificial heart pumps or mechanical support systems could be permanently installed instead of a new heart in some people. Likewise, a better understanding of the immune system may allow physicians to transplant organs of other types (xenotransplant) instead of selectively using human organs. These technologies will be more widely available within the next 20 years.

PROSPECTS FOR THE FUTURE

  • New anti-rejection drugs
  • A better understanding of vascular disease
  • Greater availability of donated organs
  • Other heart replacement options

The research will also focus on identifying people with early heart disease. Better medical treatment may prevent the disease from reaching a point when a heart transplant is needed.

There is still a reason for optimism in cases where this does not happen. As medical scientists become more aware of immune responses, donated organs will be applied with increasing success. In turn, that will result in increasing improvements in heart transplantation.

author

Miko Lamberto

Ja sam nutricionista sa 10 godina iskustva, neke od svojih zapažanja sam preneo u naš blog. Za najnovije vesti i informacije o prirodi i pridonom lečenju nas pratite.

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