Heart in a Box

A person can become an organ donor after death occurs in one of two ways: brain death or circulatory death. These pathways are similar in certain ways. In both brain and circulatory death:

• The person has experienced a devastating injury or event, such as trauma, stroke or a drug overdose.
• Health care providers have performed all possible medical care to save the person’s life.
• The person is dependent on life support and cannot recover.

But brain death and circulatory death have these significant differences:

• Brain death is the irreversible loss of all functions of the entire brain.
• Circulatory death is irreversible brain damage that does not meet the strict criteria for brain death. With circulatory death, a person may still have minor brainstem function but will not survive.

In conventional heart transplantation, surgeons retrieve hearts from organ donors after brain death (DBD). The organ donor remains on life support as surgeons retrieve the organs that are suitable for transplantation. Life support helps prevent heart damage by supplying oxygen-rich blood to the heart muscle.

If a person meets the criteria described above for circulatory death, their loved ones can decide to proceed with organ donation. The care team helps them plan a compassionate removal of life support. After the organ donor’s heart has stopped for five minutes, physicians make the determination of circulatory death. Surgeons retrieve the organs after that time.

When surgeons bring a donor heart to a recipient, they typically transport the heart in cold storage—such as an ice-filled cooler. Then it's a race against the clock to get the donor heart to the recipient. That's because the longer the heart is outside the body, the higher the chance of tissue damage.

In fact, many donor hearts go unused because they're no longer healthy by the time they reach the recipient's hospital. The heart isn't receiving any blood supply during conventional cold transportation, usually a four-hour window.

The TransMedics Organ Care System (OCS) maintains donor hearts in a warm, living, beating state during transport to help keep them healthy for transplantation. The device pumps fresh donor blood enriched with insulin, vitamins, antibiotics and other substances through the heart to provide oxygen and nutrients during transport.

Also called "heart-in-a-box," the OCS includes technology that allows doctors to monitor the heart's function during transport. Doctors can adjust settings to keep factors such as blood flow at the right levels, maintaining the heart in its best possible condition. With cold transport, doctors can't evaluate donor hearts until they arrive at the recipient's hospital—when it's too late.

For years, organ transplant surgeons have been performing DCD transplantation for other organs, such as the kidneys, liver and lungs. But because the heart isn't receiving oxygen-rich blood during the period required to declare death, the heart has a higher risk for tissue damage. Until now, DCD wasn’t an option for hearts.

Using the OCS to transport hearts retrieved through DCD, more people who desperately need a new heart have access to heart transplantation. DCD heart transplantation, combined with the OCS, could increase the pool of donor hearts—and reduce wait time for a new heart—in important ways:

• The OCS enables donor hearts to be transported farther to reach recipients, reducing the number of donor hearts that become unusable during transport.
• DCD heart retrieval provides donor hearts that might be healthier to begin with since they haven’t gone through the long process of brain death that can damage heart tissue.

In the heart trial, cardiac surgeons at Sentara are hoping to show that DCD heart transplant can be as successful as conventional DBD heart transplants. The key measures are the length of time patients survive after transplantation and how well DCD transplants work compared with DBD transplants.