A medical graft is living tissue, such as an organ or skin, moved from a donor to a recipient to replace or repair damaged tissue. The process of these new cells integrating and starting to work is called engraftment. For instance, in a bone marrow transplant, the donated cells start to produce new blood cells. Graft failure occurs when this process does not happen, or when the graft stops working later on. This can range from the graft not working from the moment of transplant to it slowly losing function over time.
Mechanisms of Graft Failure
A primary cause of graft failure is immune-mediated rejection, where the recipient’s immune system identifies the new tissue as foreign and attacks it. Hyperacute rejection occurs within minutes to hours of the transplant and is caused by pre-existing antibodies in the recipient. This type of rejection is now less common due to improved screening before transplantation.
Acute rejection is a common immune response that happens within the first few weeks to months after the transplant. Chronic rejection is a slower process that occurs over months or years. This gradual deterioration of the graft’s function is a leading cause of long-term transplant failure, seen in conditions like cardiac allograft vasculopathy (CAV), where a transplanted heart’s arteries slowly thicken.
Technical failures related to the surgery itself can also lead to graft failure. The formation of blood clots in the vessels supplying the new organ, a condition known as vascular thrombosis, can cut off blood flow and cause the tissue to die. Issues with the surgical connections between the recipient’s body and the new graft can also disrupt function.
A graft may also experience primary non-function, meaning it never starts to work after being transplanted, which can be due to factors inherent to the donor organ. Finally, the original disease that made the transplant necessary can return and attack the new graft. This recurrence of disease can lead to the eventual failure of the transplanted tissue.
Identifying Graft Failure
General symptoms of graft failure may include a feeling of discomfort, fever, and flu-like symptoms. Pain, tenderness, or swelling in the specific area of the transplant is also a common indicator.
Other symptoms are specific to the type of graft. For a kidney graft, signs of failure might include decreased urine output or swelling in the legs and ankles. For a liver graft, a person might experience jaundice, a yellowing of the skin and eyes, or abdominal bloating. Heart transplant symptoms could manifest as heart failure, with generalized swelling and shortness of breath.
To confirm a suspected graft failure, medical professionals use several diagnostic procedures. Blood tests monitor the function of the transplanted organ by measuring specific markers, like creatinine levels after a kidney transplant. Imaging studies, such as an ultrasound, are used to visualize the graft and check for proper blood flow.
The most definitive way to diagnose graft failure, particularly when rejection is suspected, is through a biopsy. This procedure involves taking a small sample of tissue from the transplanted organ to be examined under a microscope. This allows doctors to see direct evidence of damage or rejection and helps them determine the best course of action.
Medical Interventions for a Failing Graft
When a graft begins to fail due to immune rejection, the goal is to stop the body’s attack and preserve its function. The main approach involves adjusting the patient’s medication. Immunosuppressive drugs, prescribed to every transplant recipient, may be increased or changed. These medications must be taken for the life of the graft to manage the immune system’s response.
It is also important to address underlying issues that could contribute to the graft’s decline. This includes treating any infections that may have developed, as they can put additional stress on the body and the transplanted organ. A thorough evaluation is conducted to identify and manage such complications.
If the failure is due to a technical or structural problem, different interventions may be required. If a blood clot is obstructing blood flow, a procedure might be used to remove the clot and restore circulation. Similarly, if there is a problem with one of the surgical connections, another operation may be necessary to repair it.
The specific course of action depends on the cause and severity of the failure. The medical team works to stabilize the patient and the graft, with the hope of returning the transplanted organ to a state of normal function.
Outcomes After Graft Failure
When a graft cannot be saved, the focus of care shifts to managing the patient’s health and considering future options. The failed graft may need to be surgically removed, especially if it is causing pain, fever, or other symptoms that pose a risk to the patient’s well-being.
Following the loss of graft function, the patient will return to the therapies they were on before the transplant. For someone with a failed kidney graft, this means going back on dialysis. For a patient whose transplanted heart has failed, they will require medical support for heart failure while other options are considered.
After a graft has failed, the possibility of a second transplant, or re-transplantation, is often explored. This can be a viable path forward, offering another chance at a life free from the underlying disease. The evaluation for a second transplant can be more complex than the first, but it remains a common treatment for graft failure. A subsequent transplant may use cells from the original donor or from a new donor.