Heart transplantation

Indications & Contraindications - The Gatekeepers' List

• Indications: Generally, end-stage heart disease with <1 year life expectancy.

  • Refractory cardiogenic shock, NYHA Class III-IV HF
  • Intractable angina or malignant arrhythmias
  • LVEF <20%
  • Peak VO₂ <14 mL/kg/min

• Contraindications:

  • Absolute:
    • Active malignancy
    • Severe, irreversible pulmonary hypertension (PVR >5 Wood units)
    • Irreversible end-organ damage (e.g., liver, kidney)
    • Active systemic infection
  • Relative:
    • Age >70
    • Poorly controlled diabetes
    • Active substance abuse
    • Psychosocial instability

⭐ Exam Favorite: Irreversible pulmonary hypertension (high Pulmonary Vascular Resistance) is a critical absolute contraindication, as the donor right ventricle is not accustomed to high afterload and will fail.

Donor-Recipient Matching - The Perfect Match

Key matching criteria aim to minimize rejection and maximize graft survival.

• ABO Blood Group: Must be identical or compatible.
• Panel Reactive Antibody (PRA): Screens for pre-formed HLA antibodies. A high PRA indicates sensitization, making matching difficult.
• Size Match: Donor weight should be within 30% of the recipient's weight.

⭐ Cytomegalovirus (CMV) status is critical. A CMV-negative recipient should ideally receive a CMV-negative heart to prevent primary infection, a major cause of post-transplant morbidity.

Surgical Procedure - The New Engine Swap

• Standard Approach: Median sternotomy & initiation of cardiopulmonary bypass (CPB).
• Orthotopic Transplant (Biatrial Technique): Recipient's heart is explanted, leaving posterior walls of the atria with vena cavae and pulmonary veins intact.
• Anastomosis Sequence: Left atrium → Right atrium → Pulmonary artery → Aorta.

⭐ EKG Finding: The recipient's native sinoatrial (SA) node remnant can remain functional, leading to two P-waves (one from donor, one from recipient) on post-op EKG.

Immunosuppression & Rejection - Taming the Defenses

• Induction Therapy: Basiliximab (IL-2R antagonist) at time of transplant.

• Maintenance (Triple Drug Regimen):

  • Calcineurin Inhibitor (CNI): Tacrolimus (preferred) or Cyclosporine.
  • Antiproliferative: Mycophenolate Mofetil (MMF) or Azathioprine.
  • Corticosteroids: Prednisone, with gradual taper.

• Types of Rejection:

  • Hyperacute: Minutes; pre-formed antibodies; causes thrombosis.
  • Acute Cellular: 1-12 weeks; T-cell mediated; diagnosed via biopsy.
  • Antibody-Mediated (AMR): Can occur anytime; donor-specific antibodies (DSAs).
  • Chronic: >1 year; leads to Cardiac Allograft Vasculopathy (CAV).

⭐ Endomyocardial biopsy is the gold standard for monitoring and diagnosing acute cardiac allograft rejection, revealing lymphocytic infiltrate and myocyte damage.

Complications & Prognosis - The Long Road Ahead

• Infection: Highest risk in first year. Prophylaxis is key.
  • Timeline: Bacterial (early) → Opportunistic (CMV, Pneumocystis) → Fungal (late).
• Malignancy: Due to ↓ immune surveillance.
  • Most common: Skin cancers (Squamous Cell > Basal Cell).
  • Post-transplant Lymphoproliferative Disorder (PTLD), often EBV-driven.
• Graft Failure:
  • Acute/chronic rejection.
  • Cardiac Allograft Vasculopathy (CAV).

⭐ Cardiac Allograft Vasculopathy (CAV) is a diffuse, accelerated form of coronary artery disease and the leading cause of graft failure >1 year post-transplant.

• Prognosis: Median survival is ~12-13 years. 1-year survival >85%.

High‑Yield Points - ⚡ Biggest Takeaways

• Orthotopic transplantation is the standard for end-stage heart failure refractory to medical therapy.
• Key contraindications include irreversible pulmonary hypertension, active malignancy, and systemic infection.
• Endomyocardial biopsy is the gold standard for diagnosing acute cellular rejection.
• Cardiac Allograft Vasculopathy (CAV) is a major long-term cause of graft failure, presenting as diffuse coronary stenosis.
• Lifelong triple-drug immunosuppression increases risk of infection (CMV) and malignancy.
• The denervated donor heart has a higher resting heart rate and is unresponsive to atropine.