Final answer:
Patients may require a heart transplant due to conditions such as heart failure and cardiovascular diseases, which compromise the heart's ability to function. Challenges include the immune system rejecting the transplant and the scarcity of donor hearts. New technologies like heart-in-a-box are being tested to increase the number of viable donor hearts.
Step-by-step explanation:
There are several health conditions and issues that can lead to a patient requiring a heart transplant. Heart failure is one major condition where the heart cannot pump with enough force, resulting in inadequate blood flow to sustain body functions. Conditions such as cardiovascular diseases, including heart attack, stroke, and angina, often contribute to the deterioration of heart function. Additionally, certain systemic disorders like diabetes mellitus, infections, and prolonged critical illness can exacerbate cardiac issues, leading to the necessity for a transplant.
Another critical factor is the immune system's potential rejection of the transplanted organ. Genetic differences between the donor's and recipient's tissues, particularly among MHC (HLA) genes, impact the likelihood of rejection. Immunosuppressive therapy is required to mitigate this risk but comes with its challenges, including vulnerability to infections and cancer.
The limited availability of donor hearts is a significant issue. Donor hearts must be used within four hours of procurement, and they can only come from brain-dead individuals. This narrow time frame can cause logistical problems and limit the number of available hearts. However, technologies like the heart-in-a-box system are in development to increase usable donor hearts by 30%, which may improve the survival rates of patients with heart failure.