Heart-Lung Transplantation

Excerpt

Pioneered in the 1960s and successfully implemented in the 1980s, with a declining number of candidates since the 1990s, simultaneous heart and lung transplantation is only indicated for patients in the end stages of both cardiac and pulmonary failure. Suppose only 1 of the 2 thoracic organ systems has irreversibly failed, and the other is salvageable. In that case, most treatment centers forego dual transplants as the risk-benefit analyses suggest salvage should be attempted, and only the irreversibly failed organ should be replaced. This strategy spares the patient the cumulative risk of 2 simultaneous transplants, shortens their time on the waiting list, and allocates more organs to more patients. Therefore, in the current era, most patients are preferentially placed as candidates for either lung transplant or advanced heart failure therapies, including mechanical circulatory support and heart transplant.

In 2014, the United Network for Organ Sharing initiated a critical review of its heart transplantation donor allocation policy. This review was driven by several factors, including a growing imbalance between organ availability and demand, high mortality rates among the sickest patients on the waitlist, and an increase in candidates being bridged to transplant with left ventricular assist devices. The thoracic subcommittee expanded the number of priority tiers to 6 in the revised allocation policy to address these concerns, allowing for more precise risk stratification and reducing the need for status exceptions. While the subcommittee considered posttransplant survival, the main goal of the new system was to reduce mortality among waitlisted patients.

Allocation Tiers and Descriptions

Tier 1

1. Veno-arterial extracorporeal membrane oxygenation

2. Nondischargeable biventricular assist device (BiVAD)

3. Mechanical circulatory support (MCS) with arrhythmia

Tier 2

1. Dischargeable right ventricular assist device/BiVAD

2. Nondischargeable left ventricular assist devices (LVAD)

3. Intraaortic balloon pump or other percutaneous MCS

4. MCS with malfunction

Tier 3

1. Continuous intravenous (IV) inotropes with hemodynamic monitoring

2. 30-day exception period for LVAD

3. MCS with complications

Tier 4

1. Continuous IV inotropes without hemodynamic monitoring

2. Stable LVAD

3. Congenital heart disease

4. Restrictive cardiomyopathy

5. Retransplantation

Tier 5

1. Multiorgan transplant

Tier 6

1. All other candidates

Despite the advancements in organ transplantation and donor allocation strategies, heart-lung transplantation remains a rare and complex procedure, with only about 100 new cases reported annually. The challenges associated with patient selection, donor availability, and postoperative management necessitate a highly coordinated and multidisciplinary approach. Given the limited number of cases and stringent indications, healthcare professionals must stay informed about evolving guidelines, allocation policies, and therapeutic alternatives. This introduction aims to provide a comprehensive understanding of the unique considerations and current state of heart-lung transplantation, serving as a foundation for in-depth discussions on patient management, surgical techniques, and long-term outcomes in this niche area of transplant medicine.