Heterotopic heart transplantation

Heterotopic Heart Transplantation (HHT), also known as a "piggyback" heart transplant, is a complex surgical procedure in which a donor heart is transplanted alongside the patient's existing heart. Unlike the more common orthotopic heart transplantation, where the diseased heart is completely removed and replaced, in heterotopic transplantation, the patient retains their original heart. This procedure is considered in specific cases where the patient's heart retains some functional capacity or in situations where the donor heart might not be strong enough to work alone due to size mismatch or other factors.

Indications

Heterotopic heart transplantation is indicated in patients with severe heart failure when a traditional heart transplant is not viable. Indications include:

• High pulmonary vascular resistance (PVR) that might overwhelm a new, solitary donor heart.
• Size mismatches between donor and recipient where a donor heart is too small.
• Specific cases of complex congenital heart disease where removal of the native heart is not feasible.

Procedure

During a heterotopic heart transplantation, the surgeon makes an incision in the chest to expose the heart. The donor heart is then positioned so that its right atrium is connected to the right atrium of the recipient's heart, and its left atrium is connected to the left atrium of the recipient's heart. The aortas and pulmonary arteries of both hearts are also connected. This configuration allows both hearts to share the workload of pumping blood throughout the body.

Advantages and Disadvantages

Advantages

• Provides a backup support if the donor heart fails.
• Allows for a gradual transition and adaptation of the donor heart to the recipient's body.
• May be beneficial in cases of high PVR, as the native heart can help support the circulation.

Disadvantages

• Increased risk of infection due to the complexity of the surgery.
• Requires careful management of two hearts, which can complicate post-operative care.
• Potential for rejection of the donor heart, while the diseased heart continues to deteriorate.

Post-operative Care

Post-operative care for patients undergoing heterotopic heart transplantation involves close monitoring of heart function, rejection surveillance, and management of immunosuppressive medications to prevent rejection of the donor heart. Patients will also require lifelong follow-up with a cardiologist specialized in heart transplantation.

Prognosis

The prognosis for patients undergoing heterotopic heart transplantation varies depending on the underlying heart condition, the patient's overall health, and how well the body accepts the donor heart. While this procedure can extend life expectancy and improve quality of life, it is generally considered a more complex and less preferred option compared to orthotopic transplantation.

See Also

• Heart transplantation
• Cardiac surgery
• Congenital heart defect
• Heart failure