Transplant Surgery

Transplant Surgery Indian Medical PG Question 1: Acute graft rejection occurs within?

• A. Few minutes
• B. 6-12 months
• C. Few hours
• D. < 6 months (Correct Answer)

Transplant Surgery Explanation: ***< 6 months*** - **Acute graft rejection** typically occurs within the first few **weeks to months** after transplantation due to a T-cell mediated immune response against the donor organ [1]. - While it can manifest at any time, the majority of cases occur within the **first 6 months** post-transplant, making this the most appropriate time frame [1]. *Few minutes* - Rejection presenting within minutes of transplantation is characteristic of **hyperacute rejection**, which is caused by pre-existing **donor-specific antibodies** [1]. - This rapid form of rejection is mediated by **complement activation** and leads to immediate graft failure [1]. *6-12 months* - Rejection occurring in this timeframe might still be acute, but the peak incidence is generally earlier. - Rejection presenting after 6 months is often categorized as **late acute rejection** or may start to transition towards signs of chronic rejection, which occurs over a longer period. *Few hours* - Rejection within a few hours could be a very early form of **acute rejection** or a delayed presentation of **hyperacute rejection** [1]. - However, the classic presentation of acute rejection is more prolonged than a few hours, usually developing over days to weeks. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 241-242.

Transplant Surgery Indian Medical PG Question 2: What is the documented mortality rate for healthy liver donors undergoing donor hepatectomy?

• A. Mortality for donor is 0.6 to 0.8 %
• B. Mortality for donor is 0.5 %
• C. Mortality for donor is 0.2 to 0.4 % (Correct Answer)
• D. Mortality for donor is 1%

Transplant Surgery Explanation: ***Correct: Mortality for donor is 0.2 to 0.4%*** - Studies indicate that the **mortality rate** for healthy liver donors undergoing **donor hepatectomy** is very low, typically ranging from **0.2% to 0.4%**. - This rate reflects the extensive **pre-operative screening** and careful surgical techniques used to ensure donor safety. - Current data from major transplant centers worldwide support this range as the most accurate representation of donor risk. *Incorrect: Mortality for donor is 0.6 to 0.8%* - This range is **higher** than the generally accepted and documented mortality rates for healthy liver donors. - While complications can occur, fatal outcomes are rare, making this percentage an **overestimation** of actual risk. *Incorrect: Mortality for donor is 0.5%* - This mortality rate is also **higher** than the current reported rates for living liver donation in well-established centers. - Continuous advancements in surgical safety and donor selection have driven the mortality rate **below 0.5%** in most high-volume centers. *Incorrect: Mortality for donor is 1%* - A 1% mortality rate for healthy liver donors would be considered **unacceptably high** given the current standards of care. - This percentage severely **overestimates** the actual risks associated with living related liver donation and does not reflect modern surgical outcomes.

Transplant Surgery Indian Medical PG Question 3: Most common malignancy in post-transplant individuals:

• A. Kaposi sarcoma
• B. PTLD
• C. CNS lymphoma
• D. Squamous cell carcinoma of skin (Correct Answer)

Transplant Surgery Explanation: Most common malignancy in post-transplant individuals: ***Squamous cell carcinoma of skin*** - **Squamous cell carcinoma (SCC) of the skin** is the most common malignancy in post-transplant individuals, largely due to **immunosuppression** which impairs immune surveillance against oncogenic viruses and sunlight-induced mutations [1]. - The risk of SCC is significantly increased (up to 65-fold) in transplant recipients, often presenting as **multiple tumors** and exhibiting a more aggressive course than in the general population [2]. *Kaposi sarcoma* - **Kaposi sarcoma (KS)** is associated with **human herpesvirus 8 (HHV-8)** infection and is more common in transplant recipients compared to the general population, but it is not the *most common* malignancy [1]. - While its incidence is increased, it remains less frequent than skin cancers like SCC. *PTLD* - **Post-transplant lymphoproliferative disorder (PTLD)** is a significant complication of organ transplantation, primarily driven by **Epstein-Barr virus (EBV)** infection in the setting of immunosuppression [1]. - PTLD is a serious malignancy, but its overall incidence is less than that of skin cancers. *CNS lymphoma* - **CNS lymphoma** can occur in post-transplant patients, often linked to **EBV infection** and immunosuppression [1]. - Although it is a severe complication, its incidence is considerably lower than that of skin cancers in this population.

Transplant Surgery Indian Medical PG Question 4: A 23-year-old female underwent kidney transplantation and developed acute humoral rejection after 8 days, which was successfully managed with tacrolimus and another drug that suppresses both B and T lymphocytes. What is the drug that targets both B and T lymphocytes by inhibiting de novo synthesis of purines?

• A. Prednisone
• B. Methotrexate
• C. Mycophenolate mofetil (Correct Answer)
• D. Cyclophosphamide

Transplant Surgery Explanation: ***Mycophenolate mofetil*** - This drug inhibits **inosine monophosphate dehydrogenase**, an enzyme crucial for the **de novo synthesis of guanine nucleotides** in lymphocytes. - This selective inhibition effectively suppresses the proliferation and function of both **B and T lymphocytes**, making it a cornerstone in preventing transplant rejection. *Methotrexate* - **Methotrexate** is an **antimetabolite** that primarily inhibits **dihydrofolate reductase**, interfering with DNA synthesis and cell proliferation. - While it has immunosuppressive effects, its primary mechanism in inhibiting purine synthesis is not de novo synthesis in the same manner as mycophenolate mofetil. *Prednisone* - **Prednisone** is a **corticosteroid** that exerts its immunosuppressive effects through broad anti-inflammatory actions, genomic and non-genomic effects, affecting the function of various immune cells. - It does not specifically target **de novo purine synthesis** as its primary mechanism of immunosuppression. *Cyclophosphamide* - **Cyclophosphamide** is an **alkylating agent** that cross-links DNA strands, leading to cell cycle arrest and apoptosis, particularly in rapidly dividing cells like lymphocytes. - While it is a potent immunosuppressant affecting both B and T cells, its mechanism does not involve the inhibition of **de novo purine synthesis**.

Transplant Surgery Indian Medical PG Question 5: What is the consequence of preformed antibodies in organ transplantation?

• A. Delayed T-cell mediated rejection
• B. Long-term graft dysfunction due to chronic inflammation
• C. Post-transplant antibody-mediated rejection
• D. Immediate graft failure due to preformed antibodies (Correct Answer)

Transplant Surgery Explanation: ***Hyperacute rejection*** - This occurs immediately after transplant due to **preformed antibodies** reacting against donor antigens, leading to rapid allograft failure [1]. - It is typically associated with **complement activation** and often results in thrombosis of the graft vessels [1]. *Acute rejection* - Primarily mediated by **T cells** rather than preformed antibodies, occurring days to months after transplantation [2]. - Involves a **cellular immune response**, unlike hyperacute rejection which is antibody-mediated [2]. *Acute humoral rejection* - Also involves antibodies but develops **days to weeks** post-transplant rather than immediately like hyperacute rejection. - This type is characterized by a **specific antibody response** and complement activation, but is not due to preformed antibodies. *Chronic rejection* - A long-term process that develops over months to years due to **persistent immune-mediated injury** to the graft, leading to gradual loss of function. - Involves mechanisms such as **tissue fibrosis and vascular changes**, differing from the immediate action of preformed antibodies in hyperacute rejection. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 241-242. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, p. 242.

Transplant Surgery Flashcard 1 of 5

Question: _____ is the father of modern transplant surgery and performed the first human liver transplant.

Answer: Thomas Starzl

Transplant Surgery Flashcard 2 of 5

Question: The most common intestinal graft is _____ graft

Answer: small bowel

Transplant Surgery Flashcard 3 of 5

Question: Organ implanted in the same anatomic location in the recipient as it was in the donor is known as _____ transplantation

Answer: orthotoptic

Transplant Surgery Flashcard 4 of 5

Question: In a live donor, the renal artery is anastomosed end to _____ with the internal iliac artery

Answer: end

Transplant Surgery Flashcard 5 of 5

Question: Which kidney is taken during donor transplantation? Why? _____

Answer: Left